Catalysts for olefin polymerization

Abstract

The disclosure relates to a metallocene complex of formula (I) wherein Mt is Zr or Hf; X is a sigma ligand; R1 are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2 and R2' are each independently a C1-C10-hydrocarbyl, provided that at least one of R2 and R2' is an alpha-branched C3-C10-hydrocarbyl; n are each independently, same or different from each other, an integer from 1 to 5; R3 and R4 are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, -OR31, SR31, or N(R31)2,with R31 being C1-C10-hydrocarbyl, whereby at least one R3 per phenyl group and at least one R4 is not H; R5 and R6 are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7 carbocycle; R51' is C1-C10-hydrocarbyl; and R6' is C(R61)3, with R61 being linear or branched C1-C6-alkyl.

Description

[0001] CATALYSTS FOR OLEFIN POLYMERIZATION FIELD OF THE DISCLOSURE The present disclosure relates to new indenyl and indacenyl ligands, bisindenyl ligands comprising said indenyl and / or indacenyl ligands, complexes thereof, and catalysts comprising those complexes. The present disclosure also relates to the use of the new bisindenyl metallocene catalysts for the production of polypropylene homopolymers or propylene copolymers, especially with ethylene, in particular heterophasic polypropylene (hPP), with high activity levels, high molecular weight, and hence low MFR, and with ideal melting points. The catalysts are especially useful in the manufacture of propylene ethylene copolymers as they exhibit remarkable catalyst activity in such polymerizations. BACKGROUND OF THE DISCLOSURE Metallocene catalysts have been used to manufacture polyolefins for many years. Countless academic and patent publications describe the use of these catalysts in olefin polymerization. Metallocenes are now used industrially and polyethylenes and polypropylenes in particular are often produced using cyclopentadienyl based catalyst systems with different substitution patterns. WO2001048034 describes C1-symmetric bisindenyl complexes bearing one 2-isopropyl substituent. Such catalysts produce relatively high melting hPP (156 - 159 °C), but the catalysts have very low activities. In addition, the synthesis yields of the metallocenes are quite low and of low isomeric purity. WO2018091684 describes C2-symmetric rac-Me2Si(2-Me-4-(3,5-Me2Ph)-5-OMe-6-tBu- Ind)2ZrCl2 complex, that produces hPP with low Tm of 150-151 °C. WO2007116034 describes C2-symmetric complexes bearing 5-methoxy substituents and 6-tert-butyl substituents and linear 2-substituents. Such catalysts produce relatively low melting hPP of 148 to 150 °C. WO2005058916 describes a series of C1-symmetric bisindenyl complexes combining one 2-iso-propyl-4-aryl-indenyl ligand and one 2-methyl-4-aryl-indacenyl ligand. While Tmof hPP is somewhat high varying from 152 to 160°C, catalyst activities are invariably low. WO0202576 describes the C2-symmetric rac-Me2Si(2-iPr-4-(3,5-Me2Ph)-ind)2ZrCl2. This complex provides a catalyst of very low activity and hPP of relatively low Tmof 152 to 154°C). The teaching from this patent is that iPr groups lower catalyst activity without increasing hPP Tm.

[0002] Sensitivity: Internal EP1421090 describes C2-symmetric rac-Me2Si(2-iPr-4-(2-R-Ph)-ind)2ZrCl2. These complexes provide catalysts of very low activity although hPP Tmis relatively high (157- 159°C). While these prior art catalysts have their advantages, they lack in either activity or isoselectivity or both, in particular in the absence of borate containing cocatalyst, generating hPP with a relatively low melting and crystallisation temperature due to the formation of insertion regiodefects in the PP chains. The present inventors thus sought new metallocenes, which are able to provide high activity, especially in the case of the homopolymerization of propylene or in the case of copolymerization between propylene and ethylene. The desired catalysts should also have improved performance in the production of high melting temperature and high molecular weight polypropylene homopolymers. The desired catalysts should also have improved performance in the production of propylene-ethylene copolymers, for instance having high activity for high Mw copolymer products. The desired catalysts should also provide propylene-ethylene copolymers having high molecular weight. Equally important, it is desired that the new metallocene catalyst complexes can be produced with improved selectivity of the complex synthesis towards the desired anti- isomer by a simpler and higher yield synthesis than known metallocene catalyst complexes. BRIEF DESCRIPTION OF THE DISCLOSURE An object of the present disclosure is to provide new ligands, metallocene complexes, and hence catalysts that overcome the problems of the catalysts of the prior art. The object of the disclosure is achieved by metallocene complexes of formula (I), polymerization catalyst comprising said metallocene complex of formula (I), and process for polymerization of polypropylene optionally with comonomers which are characterized by what is stated in the independent claims. The preferred embodiments of the disclosure are disclosed in the dependent claims. It was surprisingly found that specific modification of C1-symmetric metallocenes incorporating alpha-branched alkyl substituent on one of the 2-positions of the ligand, preferably on the 2-position of the alkoxy indenyl ligand, in combination with specific substitution of the other ligand positions provide desired properties. The identified metallocene complexes when included in a polymerization catalyst, preferably supported catalyst system, composed of the said specific class of metallocene

[0003] Sensitivity: Internal complexes in combination with an aluminium containing cocatalyst have improved polymerization behavior, higher catalyst productivity, improved performance in the production of propylene homopolymers, propylene random copolymers and heterophasic propylene copolymers compared to systems known in the art, enabling the production of propylene-ethylene copolymers of high Mw, thus being ideal for the production of propylene random copolymers, especially propylene-ethylene random copolymers, as well as heterophasic propylene copolymers. The specific catalyst system gives a higher flexibility / freedom in the design of propylene polymers than prior art catalyst systems. An advantage of the disclosure is that these metallocenes, in particular upon MAO activation, allow the production of propylene polymers having high isotacticity, that is, produce homopolymer polypropylene (hPP) with higher Tm. In particular, the anti / syn ratio in the metallocene synthesis increases with the size of this substituent. BRIEF DESCRIPTION OF THE DRAWINGS In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which Figure 1 shows melting point of hPP as a function of MFR2. DEFINITIONS Throughout the description, the following definitions are employed: The term “C1-C20-hydrocarbyl” includes C1-C20-alkyl, C2-C20-alkenyl, C2-C20-alkynyl, C3-C20- cycloalkyl, C3-C20-cycloalkenyl, C6-C20-aryl, C7-C20-alkylaryl, and C7-C20-arylalkyl groups or of course mixtures of these groups such as cycloalkyl substituted by alkyl. Unless otherwise stated, preferred C1-C20-hydrocarbyl groups are C1-C20-alkyl, C4-C20-cycloalkyl, C5-C20-cycloalkyl-alkyl groups, C7-C20-alkylaryl groups, C7-C20-arylalkyl groups, and C6-C20- aryl groups, especially C1-C10-alkyl groups, C6-C10-aryl groups, and C7-C12-arylalkyl groups, e.g. C1-C8 alkyl groups. Most especially preferred hydrocarbyl groups are methyl, ethyl, propyl, isopropyl, tert-butyl, isobutyl, C5-C6-cycloalkyl, cyclohexylmethyl, phenyl, and benzyl. The term “C1-C10-hydrocarbyl” includes C1-C10-alkyl, C2-C10-alkenyl, C2-C10-alkynyl, C3-C10- cycloalkyl, C3-C10-cycloalkenyl, C6-C10-aryl, C7-C10-alkylaryl, and C7-C10-arylalkyl groups or of course mixtures of these groups such as cycloalkyl substituted by alkyl. Unless otherwise stated, preferred C1-C10-hydrocarbyl groups are C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl groups, C7-C10-alkylaryl groups, C7-C10-arylalkyl groups, and C6-C10- aryl groups, especially C1-C6-alkyl groups, C6-aryl groups, and C7-C10-arylalkyl groups, e.g.

[0004] Sensitivity: Internal C1-C6-alkyl groups. Most especially preferred hydrocarbyl groups are methyl, ethyl, propyl, isopropyl, tert-butyl, isobutyl, C5-C6-cycloalkyl, cyclohexylmethyl, phenyl, and benzyl. It is to be noted that linear and branched hydrocarbyl groups cannot contain cyclic units. Aliphatic hydrocarbyl groups cannot contain aryl rings. The term “heteroatoms of Group 14-16 of the Periodic Table” includes for example Si, N, O or S. The term “C4-C8-ring” as used herein in connection to -R1 2Si-, refers to cyclic groups containing 4 to 8 carbon atoms and a Si atom and includes for example silacycloalkanediyls, such as silacyclobutane, silacyclopentane, or 9-silafluorene. The term “halogen” includes fluoro, chloro, bromo, and iodo groups, especially chloro or fluoro groups, when relating to the complex definition. The oxidation state of the metal ion is governed primarily by the nature of the metal ion in question and the stability of the individual oxidation states of each metal ion. It is appreciated that in the complexes of the invention, the metal ion is coordinated by ligands X to satisfy the valence of the metal ion and to fill its available coordination sites. The nature of these sigma-ligands can vary greatly. The numbering of these rings will be evident from the structures indicated herein. Catalyst activity is defined in this application to be the amount of polymer produced / g catalyst / h. Catalyst metal activity is defined here to be the amount of polymer produced / g Metal / h. The term productivity is also sometimes used to indicate the catalyst activity although herein it designates the amount of polymer produced per unit weight of catalyst. The term “molecular weight” is used herein to refer to weight average molecular weight Mw unless otherwise stated DETAILED DESCRIPTION OF THE DISCLOSURE This invention relates to a series of new ligands, metallocene complexes, and hence catalysts that are ideal for the polymerization of propylene. Metallocene catalyst complexes The metallocene catalyst complexes of the invention are asymmetrical. Asymmetrical means simply that the two ligands forming the metallocene are different, that is, each ligand bears a set of substituents that are chemically different. The metallocene complexes of the invention are preferably chiral, racemic, bridged bisindenyl C1-symmetric metallocenes in their anti-configuration. Although the complexes

[0005] Sensitivity: Internal of the invention are formally C1-symmetric, the complexes ideally retain a pseudo-C2- symmetry since they maintain C2-symmetry in close proximity of the metal center although not at the ligand periphery. By nature of their chemistry both anti and syn enantiomer pairs (in case of C1-symmetric complexes) are formed during the synthesis of the complexes. For the purpose of this invention, racemic-anti means that the two indenyl ligands are oriented in opposite directions with respect to the cyclopentadienyl-metal-cyclopentadienyl plane, while racemic-syn means that the two indenyl ligands are oriented in the same direction with respect to the cyclopentadienyl-metal-cyclopentadienyl plane, as shown in the scheme below. Racemic Anti Racemic Syn Preferred metallocene catalyst complexes are in the anti-configuration. The metallocene complexes of the invention are preferably employed as the racemic-anti- isomers. Ideally, therefore at least 95 mol%, such as at least 98 mol%, especially at least 99 mol% of the metallocene catalyst complex is in the racemic anti-isomeric form. The present metallocene catalyst complexes require the combination of three distinctive features of the ligand framework: 1: an indacenyl ligand with 4,8-diaryl substitution, 2: a 5-alkoxy indene, preferably methoxy indene, with 6-tertiary hydrocarbyl, preferably tertiary alkyl, substituent, and 3: at least one alpha-branched alkyl substituent on one of the 2-positions of the ligand, preferably on the 2-position of the alkoxy indenyl ligand. It is to be noted that only one feature (as in example 1 in WO2005058916, having one 2- isopropyl group on the indenyl ligand) or two (as in the metallocene of example 5 in WO2005058916, with both a 4,8-diaryl substitution on indacenyl and a 2-isopropyl group on the indenyl ligand) are not enough to realize the present invention.

[0006] Sensitivity: Internal In fact, both the anti / syn ratio and the isolated yield of the anti-isomer of the metallocenes in example 1 and in example 5 of WO2005058916 are far below those obtained through the substitution pattern (3 features) of the present invention (see Table 1 below): Table 1 Ex.1 in Ex 5 in metallocene WO2005058916 WO2005058916 anti / syn ratio n.a. (mix) 61:39 isolated anti 14 3.5 isomer yield The present invention accordingly relates to metallocene complexes of formula (I) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C -C -hydrocarbyl, pro 2 1 10 vided that at least one of R and R2’ is an alpha-branched C3-C10-hydrocarbyl; n are each independently, same or different from each other, an integer from 1 to 5;

[0007] Sensitivity: Internal R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, -OR31, SR31, or N(R31)2, with R31 being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R5and R6are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7- carbocycle; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl. For the above-defined metallocene complexes of formula (I), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6-alkoxy, or R´ group, with R´ being C1-C6-alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both are C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2and R2’ are each independently, same of different from each other, alpha- branched C3-C10-hydrocarbyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or a C6-C9-aryl, provided that at least one of R2and R2’ is alpha- branched C3-C9-hydrocarbyl; more preferably R2and R2’are each independently, same or different from each other, alpha-branched C3-C6-alkyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or C6-C9-aryl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclohexyl, or phenyl, more preferably R21

[0008] Sensitivity: Internal being H or linear or branched C1-C3-alkyl, provided that at least one of R2and R2’ is alpha- branched C3-C6-alkyl. Preferably, R2and R2’ are different and one, preferably R2’, is alpha-branched C3-C10- hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2, and the other, preferably R2, is a CH2-R21-group, with R21being H or C1-C6-alkyl, more preferably H or linear C1-C3-alkyl, most preferably methyl. Preferably R2is CH2-R21, with R21being H or linear C1-C6-alkyl, such as methyl, ethyl, n- propyl, n-butyl, more preferably R21being H or linear C1-C3-alkyl, even more preferably, R2 is methyl or ethyl, most preferably methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably R2’is alpha- branched C3-C6-alkyl, even more preferably R2’is CH(CH3)2. It is preferred that R2is methyl and R2’is alpha-branched C3-C6-alkyl; more preferably, R2 is methyl and R2’is alpha-branched C3-C6-alkyl, most preferably R2is methyl and R2’is CH(CH3)2. It is preferred that each n is independently, same or different from each other, an integer from 1 to 3, such as 1, 2 or 3. Preferably, the R3and R4substituents of the respective phenyl ring are in the 3-, 4-, and / or 5-position of the ring, whereby the 1-position is attached to the indenyl ring. It is for example possible that the phenyl ring is substituted in the para position i.e. 4´ position only, like 4´-tert-butyl phenyl, or di-substituted in the meta positions, i.e.3´ and 5´ position, like 3´,5´-dimethylphenyl or 3´,5´-ditert-butylphenyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings carrying the R3and R4substituents have different substitution patterns. It is therefore preferred when n is 1, the only R3and / or R4group, respectively, is preferably in the para position. If n is 2, then the two R3and / or R4groups, respectively are preferably in the meta positions. Preferably R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, linear or branched C1-C4-alkyl, or –OR31, with R31being C1-C4-hydrocarbyl, even more preferably, each R3and R4are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert- butyl, or methoxy, especially hydrogen, methyl, or tert-butyl, whereby at least one R3per phenyl group and at least one R4is not H.

[0009] Sensitivity: Internal Preferably R5and R6form together (R56)m, wherein each (R56)mis independently -CH2-, - CHR*-, or -C(R*)2- group, with R* being C1-C2-alkyl, preferably methyl, and m being 3 to 5, preferably 3 to 4; more preferably each (R56)mis -CH2-, with m being and integer from 3 to 5, preferably 3 or 4, most preferably 3. As noted above, R51’ is C1-C10-hydrocarbyl, for example, linear or branched C1-C10- hydrocarbyl. Preferably R51’ is linear or branched C1-C6-alkyl, such as methyl, ethyl, n- propyl, i-propyl, n-butyl, i-butyl, sec-butyl, or tert-butyl, C7-C10-arylalkyl, C7-C10-alkylaryl, or C6-C10-aryl, more preferably linear C1-C6-alkyl, branched C3-C6–alkyl, or C6-aryl, even more preferably linear C1-C4-alkyl, yet even more preferably methyl or ethyl, and most preferably methyl. Preferably R6’ is C(R61)3, with R61’being linear C1-C3-alkyl; more preferably methyl. Thus advantageously, R6’ is tert-butyl. Viewed from another aspect the invention provides a metallocene catalyst complex of formula (I-a) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form, together with the Si atom they are attached to, a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2 and R2’ is an alpha-branched C3-C10-hydrocarbyl;

[0010] Sensitivity: Internal R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, -OR31, SR31, or N(R31)2, with R31 being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R5and R6are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7- carbocycle; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl. For the above-defined metallocene complexes of formula (I-a), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I-a) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6-alkoxy, or R´, with R´ being C1-C6-alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both are C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2and R2’ are each independently, same of different from each other, alpha- branched C3-C10-hydrocarbyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or a C6-C9-aryl, provided that at least one of R2and R2’ is alpha- branched C3-C9-hydrocarbyl; more preferably R2and R2’are each independently, same or different from each other, alpha-branched C3-C6-alkyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or C6-C9-aryl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclohexyl, or phenyl, more preferably R21Sensitivity: Internal being H or linear or branched C1-C3-alkyl, provided that at least one of R2and R2’ is alpha- branched C3-C6-alkyl. Preferably, R2and R2’ are different and one, preferably R2’, is alpha-branched C3-C10- hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2, and the other, preferably R2, is CH2-R21, with R21being H or C1-C6-alkyl, more preferably H or linear C1-C3-alkyl, most preferably methyl. Preferably R2is CH2-R21, with R21being H, linear C1-C6-alkyl, such as methyl, ethyl, n- propyl, n-butyl, more preferably R21being H or linear C1-C3-alkyl, even more preferably, R2 is methyl or ethyl, most preferably methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably R2’is alpha- branched C3-C6-alkyl, even more preferably R2’is CH(CH3)2. It is preferred that R2is methyl and R2’is alpha-branched C3-C6-alkyl; more preferably, R2 is methyl and R2’is alpha-branched C3-C6-alkyl, most preferably R2is methyl and R2’is CH(CH3)2. Preferably R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, a linear or branched C1-C4- alkyl, or -OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, each R3and R4are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert- butyl, or methoxy, especially hydrogen, methyl, or tert-butyl, whereby at least one R3per phenyl group and at least one R4is not H. Preferably, the R3and R4substituents of the respective phenyl ring are in the 3-, 4-, and / or 5-position of the ring, whereby the 1-position is attached to the indenyl ring. It is for example possible that the phenyl ring substituted in the para position i.e.4´ position only, like 4´-tert.-butyl phenyl, or di-substituted in the meta positions, i.e.3´ and 5´ position, like 3´,5´-dimethylphenyl or 3´,5´-ditert.-butylphenyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings have different substitution patterns. It is therefore preferred if one or two R3and / or R4groups is H. If two R3and / or R4groups are H then the remaining R3and / or R4group, respectively, is preferably in the para position. If one R3and / or R4group is H then the remaining R3and / or R4groups are preferably in the meta positions. Advantageously one or two R3per phenyl group are not H, more preferably on both phenyl groups the R3are the same, like 3´,5´-di-methyl or 4´- tert-butyl for both phenyl groups. Sensitivity: Internal For the indenyl moiety preferably one or two R4on the phenyl group are not H, more preferably two R4are not H, and most preferably these two R4are the same like 3´,5´-di- methyl or 3´,5´-di-tert-butyl. Preferably R5and R6form together (R56)m, wherein each (R56)mis independently -CH2-, - CHR*-, or -C(R*)2-, with R* being C1-C2-alkyl, preferably methyl, and m being 3 to 5, preferably 3 to 4; more preferably each (R56)mis -CH2-, with m is 3 to 5, preferably 3 to 4, most preferably 3. As noted above, R51’ is C1-C10-hydrocarbyl, for example, linear or branched C1-C10- hydrocarbyl. Preferably R51’ is linear or branched C1-C6-alkyl, such as methyl, ethyl, n- propyl, i-propyl, n-butyl, i-butyl, sec-butyl, or tert-butyl, C7-C10-arylalkyl, C7-C10-alkylaryl, or C6-C10-aryl, more preferably linear C1-C6-alkyl, branched C3-C6–alkyl, or C6-aryl, even more preferably linear C1-C4-alkyl, yet even more preferably methyl or ethyl, and most preferably methyl. Preferably R6’ is C(R61)3, with R61’being linear C1-C3-alkyl; more preferably methyl. Thus advantageously, R6’ is tert-butyl. Viewed from another aspect the invention provides a metallocene catalyst complex of formula (l-b) wherein Mt is Zr or Hf: X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; Sensitivity: Internal R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2 and R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or –OR31, with R31being C1-C10- hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R5and R6are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7carbocycle. For the above-defined metallocene complexes of formula (I-b), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I-b) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6-alkoxy, or R´, with R´ being C1-C6-alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both are C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2and R2’ are each independently, same of different from each other, alpha- branched C3-C10-hydrocarbyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or a C6-C9-aryl, provided that at least one of R2and R2’ is alpha- branched C3-C9-hydrocarbyl; more preferably R2and R2’are each independently, same or different from each other, alpha-branched C3-C6-alkyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or C6-C9-aryl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclohexyl, or phenyl, more preferably R21being H or linear or branched C1-C3-alkyl, provided that at least one of R2and R2’ is alpha- branched C3-C6-alkyl. Sensitivity: Internal Preferably, R2and R2’ are different and one, preferably R2’, is alpha-branched C3-C10- hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2, and the other, preferably R2, is CH2-R21-, with R21being H or C1-C6-alkyl, more preferably H or linear C1-C3-alkyl, most preferably methyl. Preferably R2is CH2-R21, with R21being H, linear C1-C6-alkyl, such as methyl, ethyl, n- propyl, n-butyl, more preferably R21being H or linear C1-C3-alkyl, even more preferably, R2 is methyl or ethyl, most preferably methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably R2’is alpha- branched C3-C6-alkyl, even more preferably R2’is CH(CH3)2. It is preferred that R2is methyl and R2’is alpha-branched C3-C6-alkyl; more preferably, R2is methyl and R2’is alpha-branched C3-C6-alkyl, most preferably R2is methyl and R2’is CH(CH3)2. Preferably R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, a linear or branched C1-C4- alkyl, or -OR31, with R31being a C1-C 4-hydrocarbyl. Even more preferably, each R3and R4are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert- butyl, or methoxy, especially H, methyl, or tert-butyl, whereby at least one R3per phenyl group and at least one R4is not H. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings have different substitution patterns. It is therefore preferred if one or two R3and / or R4groups per phenyl group is H. If two R3and / or R4groups are H then the remaining R3and / or R4group, respectively, is preferably in the para position. If one R3and / or R4group is H then the remaining R3and / or R4groups are preferably in the meta positions. Advantageously one or two R3per phenyl group are not H, more preferably on both phenyl groups the R3are the same, like 3´,5´-di-methyl or 4´- tert-butyl for both phenyl groups. For the indenyl moiety preferably one or two R4on the phenyl group are not H, more preferably two R4are not H, and most preferably these two R4are the same like 3´,5´-di- methyl or 3´,5´-di-tert-butyl. Preferably R5and R6form together (R56)m, wherein each (R56)m is independently -CH2-, - CHR*-, or -C(R*)2-, with R* being C1-C2-alkyl, preferably methyl, and m being 3 to 5, preferably 3 to 4; more preferably each (R56)m is -CH2-, with m is 3 to 5, preferably 3 to 4, most preferably 3. Sensitivity: Internal Viewed from another aspect the invention provides a metallocene catalyst complex of formula (I-c) (I-c) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10- hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl. For the above-defined metallocene complexes of formula (I-c), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I-c) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6-alkoxy, or R´, with R´ being C1-C6-alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or Sensitivity: Internal methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both are C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2and R2’ are each independently, same of different from each other, alpha- branched C3-C10-hydrocarbyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or a C6-C9-aryl, provided that at least one of R2and R2’ is alpha- branched C3-C9-hydrocarbyl; more preferably R2and R2’are each independently, same or different from each other, alpha-branched C3-C6-alkyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or C6-C9-aryl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclohexyl, or phenyl, more preferably R21being H or linear or branched C1-C3-alkyl, provided that at least one of R2and R2’ is alpha- branched C3-C6-alkyl. Preferably, R2and R2’ are different and one, preferably R2’, is alpha-branched C3-C10- hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2, and the other, preferably R2, is a CH2-R21, with R21being H or C1-C6-alkyl, more preferably H or linear C1-C3-alkyl, most preferably methyl. Preferably R2is CH2-R21, with R21being H, linear C1-C6-alkyl, such as methyl, ethyl, n- propyl, n-butyl, more preferably R21being H or linear C1-C3-alkyl, even more preferably, R2is methyl or ethyl, most preferably methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably R2’is alpha- branched C3-C6-alkyl, even more preferably R2’is CH(CH3)2. It is preferred that R2is methyl and R2’is alpha-branched C 2 3-C6-alkyl; more preferably, R is methyl and R2’is alpha-branched C3-C6-alkyl, most preferably R2is methyl and R2’is CH(CH3)2. Preferably R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, a linear or branched C1-C4-alkyl, or -OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, each R3and R4are Sensitivity: Internal each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert- butyl, or methoxy, especially hydrogen, methyl, or tert-butyl, whereby at least one R3per phenyl group and at least one R4is not H. Preferably, the R3and R4substituents of the respective phenyl ring are in the 3-, 4-, and / or 5-position of the ring, whereby the 1-position is attached to the indenyl ring. It is for example possible that the phenyl ring substituted in the para position i.e.4´ position only, like 4´-tert.-butyl phenyl, or di-substituted in the meta positions, i.e.3´ and 5´ position, like 3´,5´-dimethylphenyl or 3´,5´-ditert.-butylphenyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings have different substitution patterns. It is therefore preferred if one or two R3and / or R4groups is H. If two R3and / or R4groups are H then the remaining R3and / or R4group, respectively, is preferably in the para position. If one R3and / or R4group is H then the remaining R3and / or R4groups are preferably in the meta positions. Advantageously one or two R3per phenyl group are not H, more preferably on both phenyl groups the R3are the same, like 3´,5´-di-methyl or 4´- tert-butyl for both phenyl groups. For the indenyl moiety preferably one or two R4on the phenyl group are not H, more preferably two R4are not H, and most preferably these two R4are the same like 3´,5´-di- methyl or 3´,5´-di-tert-butyl. As noted above, R51’ is C1-C10-hydrocarbyl, for example, linear or branched C1-C10- hydrocarbyl. Preferably R51’ is linear or branched C1-C6-alkyl, such as methyl, ethyl, n- propyl, i-propyl, n-butyl, i-butyl, sec-butyl, or tert-butyl, C7-C10-arylalkyl, C7-C10-alkylaryl, or C6-C10-aryl, more preferably linear C1-C6-alkyl, branched C3-C6-alkyl or C6-aryl, even more preferably linear C1-C4-alkyl, yet even more preferably methyl or ethyl, and most preferably methyl. Preferably R6’ is C(R61)3, with R61’being linear C1-C3-alkyl; more preferably methyl. Thus advantageously, R6’ is tert-butyl. Sensitivity: Internal Viewed from another aspect the invention provides a metallocene catalyst complex of formula (I-d) (I-d) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10- hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H. For the above-defined metallocene complexes of formula (I-d), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I-d) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6-alkoxy, or R´, with R´ being C1-C6-alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Sensitivity: Internal Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both are C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2and R2’ are each independently, same of different from each other, alpha- branched C3-C10-hydrocarbyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or a C6-C9-aryl, provided that at least one of R2and R2’ is alpha- branched C3-C9-hydrocarbyl; more preferably R2and R2’are each independently, same or different from each other, alpha-branched C3-C6-alkyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or C6-C9-aryl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclohexyl, or phenyl, more preferably R21being H or linear or branched C1-C3-alkyl, provided that at least one of R2and R2’ is alpha- branched C3-C6-alkyl. Preferably, R2and R2’ are different and one, preferably R2’, is alpha-branched C3-C10- hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2, and the other, preferably R2, is a CH2-R21, with R21being H or C1-C6-alkyl, more preferably H or linear C1-C3-alkyl, most preferably methyl. Preferably R2is CH2-R21, with R21being H, linear C1-C6-alkyl, such as methyl, ethyl, n- propyl, n-butyl, more preferably R21being H or linear C -C -alky 2 1 3 l, even more preferably, R is methyl or ethyl, most preferably methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably R2’is alpha- branched C3-C6-alkyl, even more preferably R2’is CH(CH3)2. It is preferred that R2is methyl and R2’is alpha-branched C 2 3-C6-alkyl; more preferably, R is methyl and R2’is alpha-branched C3-C6-alkyl, most preferably R2is methyl and R2’is CH(CH3)2. Preferably R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, linear or branched C1-C4-alkyl, or -OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, each R3and R4are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert- butyl, or methoxy, especially hydrogen, methyl, or tert-butyl. Sensitivity: Internal Preferably, the R3and R4substituents of the respective phenyl ring are in the 3-, 4-, and / or 5-position of the ring, whereby the 1-position is attached to the indenyl ring. It is for example possible that the phenyl ring substituted in the para position i.e.4´ position only, like 4´-tert.-butyl phenyl, or di-substituted in the meta positions, i.e.3´ and 5´ position, like 3´,5´-dimethylphenyl or 3´,5´-ditert.-butylphenyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings have different substitution patterns. It is therefore preferred if one or two R3and / or R4groups is H. If two R3and / or R4groups are H then the remaining R3and / or R4group, respectively, is preferably in the para position. If one R3and / or R4group is H then the remaining R3and / or R4groups are preferably in the meta positions. Advantageously one or two R3per phenyl group are not H, more preferably on both phenyl groups the R3are the same, like 3´,5´-di-methyl or 4´- tert-butyl for both phenyl groups. For the indenyl moiety preferably one or two R4on the phenyl group are not H, more preferably two R4are not H, and most preferably these two R4are the same like 3´,5´-di- methyl or 3´,5´-di-tert-butyl. Viewed from another aspect the invention provides a metallocene catalyst complex of formula (I-e) wherein Mt is Zr or Hf; X is a sigma ligand; Sensitivity: Internal R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10- hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H. For the above-defined metallocene complexes of formula (I-e), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I-e) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6-alkoxy, or R´, with R´ being C1-C6-alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both are C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably alpha-branched C3- C6-alkyl, even more preferably CH(CH3)2. Preferably R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, linear or branched C1-C4-alkyl, or -OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, each R3and R4are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert- butyl, or methoxy, especially hydrogen, methyl, or tert-butyl, whereby at least one R3per phenyl group and at least one R4is not H. Preferably, the R3and R4substituents of the respective phenyl ring are in the 3-, 4-, and / or 5-position of the ring, whereby the 1-position is attached to the indenyl ring. Sensitivity: Internal It is for example possible that the phenyl ring substituted in the para position i.e.4´ position only, like 4´-tert.-butyl phenyl, or di-substituted in the meta positions, i.e.3´ and 5´ position, like 3´,5´-dimethylphenyl or 3´,5´-ditert.-butylphenyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings have different substitution patterns. It is therefore preferred if one or two R3and / or R4groups is H. If two R3and / or R4groups are H then the remaining R3and / or R4group, respectively, is preferably in the para position. If one R3and / or R4group is H then the remaining R3and / or R4groups are preferably in the meta positions. Advantageously one or two R3per phenyl group are not H, more preferably on both phenyl groups the R3are the same, like 3´,5´-di-methyl or 4´- tert-butyl for both phenyl groups. For the indenyl moiety preferably one or two R4on the phenyl group are not H, more preferably two R4are not H, and most preferably these two R4are the same like 3´,5´-di- methyl or 3´,5´-di-tert-butyl. Viewed from another aspect the invention provides a metallocene catalyst complex of formula (I-f) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8ring; Sensitivity: Internal R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2 and R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10- hydrocarbyl. For the above-defined metallocene complexes of formula (I-f), the following represent preferable embodiments, which can be selected alone or in combination: In a complex of formula (I-f) it is preferred if Mt is Zr or Hf, preferably Zr. Each X is a sigma ligand. Preferably, each X is independently, same or different from each other, H, halogen, C1-C6alkoxy, or R´, with R´ being C1-C6alkyl, phenyl, or benzyl. More preferably, each X is independently, same or different from each other, Cl, benzyl, or methyl. It is preferred that both X groups are the same. Most preferably both X are Cl, methyl, or benzyl, especially Cl. Preferably R1are each independently, same or different from each other, C1-C10- hydrocarbyl, more preferably C1-C10-alkyl, C4-C10-cycloalkyl, C5-C10-cycloalkyl-alkyl, C7- C10-arylalkyl, C6-C10-aryl, or C7-C10-alkylaryl, such as methyl, ethyl, propyl, isopropyl, tert- butyl, isobutyl, C3-C8-cycloalkyl, cyclohexylmethyl, phenyl, or benzyl, even more preferably both C1-C6-alkyl, C5-C6-cycloalkyl, or C6-aryl. In an embodiment each R1is independently, same or different from each other, C1-C10-alkyl, optionally substituted with C1-C10-alkoxy. It is preferred that both R1groups are the same. Most preferably, both R1are methyl. Preferably R2and R2’ are each independently, same of different from each other, alpha- branched C3-C10-hydrocarbyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or a C6-C9-aryl, provided that at least one of R2and R2’ is alpha- branched C3-C9-hydrocarbyl; more preferably R2and R2’are each independently, same or different from each other, alpha-branched C3-C6-alkyl or CH2-R21, with R21being H, linear or branched C1-C6-alkyl, a C3-C8-cycloalkyl, or C6-C9-aryl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, cyclohexyl, or phenyl, more preferably R21being H or linear or branched C1-C3-alkyl, provided that at least one of R2and R2’ is alpha- branched C3-C6-alkyl. Preferably, R2and R2’ are different and one, preferably R2’, is alpha-branched C3-C10- hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2, and the other, preferably R2, is a CH2-R21, with R21being H or C1-C6-alkyl, more preferably H or linear C1-3-alkyl, most preferably methyl. Sensitivity: Internal Preferably R2is CH2-R21, with R21being H, linear C1-C6-alkyl, such as methyl, ethyl, n- propyl, n-butyl, more preferably R21being H or linear C1-C3-alkyl group, even more preferably, R2is methyl or ethyl, most preferably methyl. Preferably R2’is alpha-branched C3-C10-hydrocarbyl; more preferably R2’is alpha- branched C3-C6-alkyl, even more preferably R2’is CH(CH3)2. It is preferred that R2is methyl and R2’is alpha-branched C3-C6-alkyl; more preferably, R2 is methyl and R2’is alpha-branched C3-C6-alkyl, most preferably R2is methyl and R2’is CH(CH3)2. Preferably R3and R4are each independently, same or different from each other, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably a linear or branched C1-C4-alkyl, or - OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, each R3and R4are each independently, same or different from each other, methyl, ethyl, isopropyl, tert-butyl, or methoxy, especially hydrogen, methyl, or tert-butyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the three phenyl rings have different substitution patterns. Advantageously on both phenyl groups the R3are the same, like 3´,5´-di-methyl for both phenyl groups. For the indenyl moiety most preferably the two R4are the same like 3´,5´-di-methyl or 3´,5´- di-tert-butyl. Intermediates Whilst the invention primarily relates to catalysts, it will be appreciated that the complexes of the invention and the ligands used to form those complexes are also new. The novel ligands of the present invention bear the combination of the distinctive features of the metallocene ligand framework: 1: an indacenyl ligand with 4,8-diaryl substitution and an alpha-branched alkyl substituent on the 2-position of the ligand; and 2: a 5-alkoxy indene, preferably methoxy indene, with 6-tertiary hydrocarbyl, preferably tertiary alkyl, substituent, and an alpha-branched alkyl substituent on the 2-position of the ligand. Sensitivity: Internal The present invention accordingly further relates to indenes of formula (II) wherein the dotted lines represent a double bond present in between carbons 1 and 2 or 2 and 3 of the indenyl ring; R2’ is an alpha-branched C3-C10-hydrocarbyl; R4are each independently, same or different from each other, H, linear or branched C1- C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10- hydrocarbyl, whereby at least one R4is not H; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl. For the above-defined indenes of formula (II), the following represent preferable embodiments, which can be selected alone or in combination: R2’ is alpha-branched C3-C10-hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2. Preferably R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, a linear or branched C1-C4-alkyl, or -OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, each R4are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert-butyl, or methoxy, especially H, methyl, or tert-butyl. It is preferred that one or two R4groups is H. If two R4groups are H then the remaining R4group is preferably in the para position. If one R4group is H then the remaining R4groups are preferably in the meta positions. Preferably two R4are not H, and most preferably these two R4are the same like 3´,5´-di- methyl or 3´,5´-di-tert-butyl. Sensitivity: Internal As noted above, R51’ is C1-C10-hydrocarbyl, for example, linear or branched C1-C10- hydrocarbyl. Preferably R51’ is linear or branched C1-C6-alkyl, such as methyl, ethyl, n- propyl, i-propyl, n-butyl, i-butyl, sec-butyl, or tert-butyl, C7-C10-arylalkyl, C7-C10-alkylaryl, or C6-C10-aryl, more preferably linear C1-C6-alkyl, branched C3-C6–alkyl, or C6-aryl, even more preferably linear C1-C4-alkyl, yet even more preferably methyl or ethyl, and most preferably methyl. Preferably R6’ is C(R61)3, with R61’being linear C1-C3-alkyl; more preferably methyl. Thus advantageously, R6’ is tert-butyl. The present invention accordingly further relates to indenes of formula (III) wherein the dotted lines represent a double bond present in between carbons 1 and 2 or 2 and 3 of the indenyl ring; R2is an alpha-branched C3-C10-hydrocarbyl; R3are each independently, same or different from each other, H, linear or branched C1- C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10- hydrocarbyl, whereby at least one R3per phenyl group is not H. For the above-defined indenes of formula (III), the following represent preferable embodiments, which can be selected alone or in combination: R2is alpha-branched C3-C10-hydrocarbyl; more preferably alpha-branched C3-C6-alkyl, even more preferably CH(CH3)2. Sensitivity: Internal Preferably R3are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, or C6-C20-aryl, more preferably H, a linear or branched C1-C4-alkyl, or -OR31, with R31being a C1-C4-hydrocarbyl. Even more preferably, R3are each independently, same or different from each other, H, methyl, ethyl, isopropyl, tert-butyl, or methoxy, especially H, methyl, or tert-butyl. Furthermore, it is possible that each of the phenyl rings have the same substitution pattern or that the two phenyl rings have different substitution patterns. It is preferred that one or two R3per phenyl group is H. If two R3groups per phenyl groups are H then the remaining R3group is preferably in the para position. If one R3per phenyl ring is H then the remaining R3groups are preferably in the meta positions. Advantageously two R3per phenyl group are not H, more preferably on both phenyl groups the R3are the same, like 3´,5´-di-methyl or 4´- tert-butyl for both phenyl groups. Synthesis The ligand of the metallocenes include two different indenes, one alkoxyindene and one indacene with 4,8-diaryl substitution. The ligands required to form the complexes and hence catalysts of the invention can be synthesized by any process and the skilled organic chemist would be able to devise various synthetic protocols for the manufacture of the necessary ligand materials. For example, WO 2007 / 116034 discloses the necessary chemistry. Synthetic protocols can also generally be found in WO2002 / 02576, WO2011 / 135004, WO2012 / 084961, WO2012 / 001052, WO2011 / 076780, WO2015 / 158790, WO2018 / 122134, WO2019 / 179959, and WO2012 / 058740. The examples section also provides the skilled person with sufficient direction. It is appreciated that the metallocenes that are obtained can exist as both anti- or syn- isomers. It is however preferred that the metallocene of the invention is the anti-isomer. Polymerization catalyst Viewed from a further aspect the invention provides a polymerization catalyst comprising, preferably consists of (i) a metallocene complex of formula (I); (ii) a cocatalyst comprising a group 13 element; and (iii) optionally a support. Sensitivity: Internal Catalyst Manufacture The metallocene complex as described above is used in combination with a suitable cocatalyst combination as described below. The metallocene catalysts can be used in supported or unsupported form. The particulate support material used is preferably an organic or inorganic material, such as silica, alumina or zirconia or a mixed oxide such as silica-alumina, in particular silica, alumina or silica- alumina. The use of a silica support is preferred. The skilled person is aware of the procedures required to support a metallocene catalyst. Especially preferably the support is a porous material so that the complex may be loaded into the pores of the support, e.g. using a process analogous to those described in WO94 / 14856 (Mobil), WO95 / 12622 (Borealis) and WO2006 / 097497. The particle size is not critical but is preferably in the range 5 to 200 μm, more preferably 20 to 80 μm. The use of these supports is routine in the art. Especially preferred procedures for producing such supported catalysts are those described in EP1828266, WO 2020 / 239598, and WO 2020 / 239603. Alternatively, no support is used at all. Such a catalyst can be prepared in solution, for example in an aromatic solvent like toluene, by contacting the metallocene (as a solid or as a solution) with the cocatalyst, for example methylaluminoxane or a borane or a borate salt previously dissolved in an aromatic solvent, or can be prepared by sequentially adding the dissolved catalyst components to the polymerization medium. In one aspect, no external carrier is used but the catalyst is still presented in solid particulate form. Thus, no external support material, such as inert organic or inorganic carrier, for example silica as described above is employed, but the solid catalyst is prepared using an emulsion-solidification method. Such catalysts can be prepared as described for example in WO 2003 / 051934, WO 2014 / 060540, and WO 2019 / 179959. The catalyst system of the invention is preferably used in supported form. The particulate support material used is an inorganic porous support such as a silica, alumina or a mixed oxide such as silica-alumina, in particular silica. The use of a silica support is preferred. The complex may be loaded into the pores of the particulate support, e.g. using a process analogous to those described in W094 / 14856, W095 / 12622, W02006 / 097497, and EP18282666. Sensitivity: Internal The average particle size of the support such as silica support can be typically from 10 to 100 µm. However, it has turned out that special advantages can be obtained, if the support has an average particle size from 15 to 80 µm, preferably from 18 to 50 µm. The average pore size of the inorganic porous support such as silica support can be in the range from 10 to 100 nm and the pore volume from 1 to 3 mL / g. The pore diameter of the inorganic porous support such as silica support can be in the range from 20 to 40 nm. The surface area of the inorganic porous support such as silica support can be typically in the range from 100 to 400 m2 / g. Examples of suitable support materials are, for instance, ES757 produced and marketed by PQ Corporation, Sylopol 948 produced and marketed by Grace or SUNSPERA DM-L- 303 silica produced by AGC Si-Tech Co. Supports can be optionally calcined prior to the use in catalyst preparation in order to reach optimal silanol group content. The use of these supports is routine in the art. The catalyst can contain from 5 to 500 µmol, such as 10 to 100 µmol of transition metal of the metallocene per gram of support such as silica, and 3 to 15 mmol of Al per gram of support such as silica. A metallocene catalyst containing such metallocenes may be produced by a process including the steps of P1-a) combining the porous inorganic support with a first portion of the aluminoxane cocatalyst in a hydrocarbon solvent to obtain aluminoxane cocatalyst treated support, optionally followed by thermal treatment of the aluminoxane treated support; P1-b) dissolving the metallocene complex in a hydrocarbon solvent, optionally adding a second portion of the aluminoxane cocatalyst in the hydrocarbon solvent and optionally the boron containing cocatalyst, wherein the amount of the first portion of the aluminoxane cocatalyst added in step a) is 75.0 to 100.0 wt% of the total amount of aluminoxane cocatalyst and the amount of the second portion of the aluminoxane cocatalyst added in step b) is 0.0 to 25.0 wt% of the total amount of aluminoxane cocatalyst and the boron containing cocatalyst, when present, is added in an amount that a boron / M molar ratio of feed amounts in the range of 0.1 :1 to 10:1 is reached; P1-c) adding the solution obtained in step b) to the aluminoxane cocatalyst treated support obtained in step a) and optionally P1-d) drying the so obtained supported catalyst system. Sensitivity: Internal In step P1-b) of the process, the components can be mixed in any order. The optional boron containing cocatalyst can be mixed with the metallocene complex dissolved in the hydrocarbon solvent and followed by addition the optional aluminoxane, or the metallocene complex dissolved in the hydrocarbon solvent can be mixed with the optional aluminoxane and a hydrocarbon followed by addition of boron containing cocatalyst and so on. In some embodiments, all components might be combined simultaneously. Only one impregnation step is used, i.e. the treated support of step a) is loaded only in one step with the metallocene. In a preferred aspect of the present invention the process comprises P2-a) combining the porous inorganic support with aluminoxane cocatalyst in a hydrocarbon solvent to obtain aluminoxane cocatalyst treated support, optionally followed by thermal treatment of the aluminoxane treated support, filtering off the hydrocarbon solvent, optionally washing with an aromatic solvent, repeating the filtration and washing steps to remove unreacted aluminium compounds; drying the final aluminoxane cocatalyst treated support; P2-b) dissolving the metallocene in a hydrocarbon solvent optionally adding a methylaluminoxane cocatalyst in a hydrocarbon solvent, wherein the amount of methylaluminoxane cocatalyst added in step a) is 75.0 to 100.0 wt% of the total amount of methylaluminoxane cocatalyst and the amount of aluminoxane cocatalyst added in step b) is 0.0 to 25.0 wt% of the total amount of methylaluminoxane cocatalyst, to obtain a metallocene solution optionally comprising aluminoxane cocatalyst; P2-c adding the metallocene solution to the aluminoxane cocatalyst treated support obtained in step a) and optionally P2-d) drying the so obtained supported catalyst system. If desired, the obtained supported catalyst system may be provided as an oil slurry with a desired solid content. The solid catalyst content in the slurry may be e.g. up to 30 wt%, like up to 25 wt%. The amounts of support, aluminoxane, preferably MAO, boron containing cocatalyst and metallocene depend on the desired herein defined ratios (boron / M, Al / M, Al / SiO2, M / SiO2). Cocatalyst To form an active catalytic species it is normally necessary to employ a cocatalyst as is well known in the art. Cocatalysts comprising one or more compounds of Group 13 metals, Sensitivity: Internal like organoaluminium, organoboron, and / or borate compounds used to activate metallocene catalysts are suitable for use in this invention. According to the present invention a cocatalyst system comprising a boron containing cocatalyst and / or an aluminoxane cocatalyst may be used in combination with the above defined metallocene catalyst complex. Preferably only cocatalysts comprising aluminium, like organoaluminium compounds used to activate metallocene catalysts, are utilized in this invention. In a preferred aspect of the present invention a cocatalyst system comprising an aluminoxane cocatalyst is advantageously used in combination with the above defined metallocene catalyst complex. Thus, preferably no further cocatalysts comprising one or more compounds of Group 13 metals other than aluminium, like organoboron and / or borate compounds, used to activate metallocene catalysts are comprised in the polymerization catalyst. Suitable amounts of cocatalyst will be well known to the person skilled in the art. Preferably, the amount of cocatalyst is chosen to reach below defined molar ratios. The molar ratio of Al from the aluminoxane to the metal ion (Mt) (preferably zirconium) of the metallocene Al / Mt may be in the range 10:1 to 2000:1 mol / mol, preferably 50:1 to 1000:1, and more preferably 100:1 to 600:1 mol / mol. When a boron cocatalyst is used, the molar ratio of boron (B) to the metal ion (Mt) (preferably zirconium) of the metallocene B / Mt may be in the range 0.1:1 to 10:1 mol / mol, preferably 0.3:1 to 7:1, especially 0.5:1 to 3:1 mol / mol. Even more preferably, the molar ratio of feed amounts of boron (B) to metal ion (Mt), preferably zirconium, of the metallocene B / Mt is from 0.5:1 to 2:1 Aluminoxane cocatalyst The aluminoxane cocatalyst can be one of formula (A): where n is usually from 6 to 20 and R has the meaning below. Aluminoxanes are formed on partial hydrolysis of organoaluminum compounds, for example those of the formula AlR3, AlR2Y and Al2R3Y3where R can be, for example, C1- Sensitivity: Internal C10-alkyl, preferably C1-C5-alkyl, or C3-C10-cycloalkyl, C7-C12-arylalkyl or -alkylaryl and / or phenyl or naphthyl, and where Y can be hydrogen, halogen, preferably chlorine or bromine, or C1-C10-alkoxy, preferably methoxy or ethoxy. The resulting oxygen-containing aluminoxanes are not in general pure compounds but mixtures of oligomers of the formula (A). The preferred aluminoxane is methylaluminoxane (MAO). Since the aluminoxanes used according to the invention as cocatalysts are not, owing to their mode of preparation, pure compounds, the molarity of aluminoxane solutions hereinafter is based on their aluminium content. Boron containing cocatalyst According to the present invention, the aluminoxane cocatalyst can be used in combination with a boron containing cocatalyst. It will be appreciated by the person skilled in the art that where boron based cocatalysts are employed, it is normal to pre-alkylate the complex by reaction thereof with an aluminium alkyl compound, such as TIBA. This procedure is well known and any suitable aluminium alkyl, e.g. Al(C1-C6 alkyl)3 can be used. Preferred aluminium alkyl compounds are triethylaluminium, tri-isobutylaluminium, tri-isohexylaluminium, tri-n-octylaluminium and tri-isooctylaluminium. Alternatively, when a borate cocatalyst is used, the metallocene complex is in its alkylated version, that is for example a dimethyl or dibenzyl metallocene complex can be used. Boron containing cocatalysts of interest include those of formula (B) BY3 (B) wherein Y is the same or different and is a hydrogen atom, C1-10-haloalkyl, or C6-C20- haloaryl, or fluorine, chlorine, bromine or iodine. Preferred examples for Y are fluorine, trifluoromethyl, unsaturated groups such as haloaryl like p-fluorophenyl, 3,5-difluorophenyl, pentachlorophenyl, pentafluorophenyl, 3,4,5-trifluorophenyl and 3,5-di(trifluoromethyl)phenyl. Most preferably, Y are fluorine, trifluoromethyl, aromatic fluorinated groups such as p- fluorophenyl, 3,5-difluorophenyl, pentafluorophenyl, 3,4,5-trifluorophenyl and 3,5- di(trifluoromethyl)phenyl. Preferred boron containing cocatalysts of formula (B) are trifluoroborane, tris(4- fluorophenyl)borane, tris(3,5-difluorophenyl)borane, tris(2,4,6-trifluorophenyl)borane, tris(penta-fluorophenyl)borane, and / or tris(3,4,5-trifluorophenyl)borane. Sensitivity: Internal Particular preference is given to tris(pentafluorophenyl)borane. However it is preferred that borates are used, i.e. compounds containing a borate anion. These compounds have formula (C): Z4B–-W+(C) wherein Z is a substituted phenyl derivative, said substituent being halo-C1-C6-alkyl or halogen; and W+is a cationic counterion. Preferably the substituents of Z are are fluoro or trifluoromethyl. Most preferably, the phenyl group is perfluorinated. The borate anion Z4B–is preferably a weakly-coordinating anion such as tetrakis(pentafluorophenyl)borate. Suitable cationic counterions W+are triarylcarbenium such as triphenylcarbenium or protonated amine or aniline derivatives such as methylammonium, anilinium, dimethylammonium, diethylammonium, N- methylanilinium, diphenylammonium, N,N-dimethylanilinium, trimethylammonium, triethylammonium, tri-n- butylammonium, methyldiphenylammonium, pyridinium, p-bromo-N,N- dimethylanilinium or p-nitro-N,N-dimethylanilinium. Preferred ionic compounds which can be used according to the present invention include: tributylammoniumtetra(pentafluorophenyl)borate, tributylammoniumtetra(trifluoromethylphenyl)borate, tributylammoniumtetra(4-fluorophenyl)borate, N,N-dimethylcyclohexylammoniumtetrakis(pentafluorophenyl)borate, N,N-dimethylbenzylammoniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, N,N-di(propyl)ammoniumtetrakis(pentafluorophenyl)borate, di(cyclohexyl)ammoniumtetrakist(pentafluorophenyl)borate, triphenylcarbeniumtetrakis(pentafluorophenyl)borate, or ferroceniumtetrakis(pentafluorophenyl)borate. Preference is given to triphenylcarbeniumtetrakis(pentafluorophenyl) borate, N,N- dimethylcyclohexylammoniumtetrakis(pentafluorophenyl)borate or N,N- dimethylbenzylammoniumtetrakis(pentafluorophenyl)borate. Mostly preferred are triphenylcarbeniumtetrakis(pentafluorophenyl) borate, Sensitivity: Internal N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, N,N- dimethylcyclohexylammoniumtetrakis(pentafluorophenyl)borate, or N,N- dimethylbenzylammoniumtetrakis(pentafluorophenyl)borate. Polymerization The catalysts according to the invention are suitable for the production of propylene homopolymers, propylene-ethylene copolymers or propylene C4-10 alpha olefin copolymers, in particular heterophasic polypropylene and propylene-ethylene copolymers. Accordingly, the present disclosure relates to a process for producing a propylene homopolymer, a propylene random copolymer or a heterophasic propylene copolymer using the specific catalyst system, as defined before. The ethylene content in such a propylene-ethylene polymer may vary depending on the desired properties of the polymer. Typically, ethylene content will range from 0.1 to 10 mol%. Especially, the catalysts of the present invention are used to manufacture propylene homopolymers or propylene copolymers with ethylene as comonomer and propylene copolymers with butene as a comonomer. Thus, the present invention relates to a process for the polymerization of propylene, propylene and ethylene, or propylene and a C4-10 alpha olefin in the presence of a polymerization catalyst as described herein. In an preferred aspect the present invention relates to a process for the preparation of a heterophasic polypropylene copolymer (hPP) comprising (I) polymerizing propylene in bulk in the presence of a polymerization catalyst as defined herein to form a polypropylene homopolymer matrix; (II) in the presence of said matrix and said polymerization catalyst and in the gas phase, polymerizing propylene and ethylene to form a heterophasic polypropylene copolymer comprising a homopolymer matrix and an ethylene propylene rubber. In a further aspect the present invention relates to a process for the preparation of a heterophasic polypropylene copolymer comprising (I) polymerizing propylene in bulk in the presence of polymerization catalyst as defined herein to form a polypropylene homopolymer; (II) in the presence of said homopolymer and said polymerization catalyst and in the gas phase, polymerizing propylene to form a polypropylene homopolymer matrix; Sensitivity: Internal (III) in the presence said matrix and said polymerization catalyst and in the gas phase, polymerizing propylene and ethylene to form a heterophasic polypropylene copolymer comprising a homopolymer matrix and an ethylene propylene rubber (EPR). Polymerization in the method of the invention may be effected in one or more, e.g.1, 2, or 3, polymerization reactors, using conventional polymerization techniques, e.g. gas phase, solution phase, slurry or bulk polymerization, or combinations thereof, like a combination of a slurry and at least one gas phase reactor. The process may also involve an in-line pre-polymerization step. This pre-polymerization step is a conventional step used routinely in polyolefin production plants and can be carried out in a continuously stirred tank reactor (CSTR) or a loop reactor, from which the prepolymerized catalyst is then transferred together with the liquid monomer(s) into the main loop reactor. Prepolymerization can be carried out at temperatures between -10 °C and 50 °C, preferably between 10 °C and 40 °C. In case of propylene polymerization in slurry reactors, like a liquid loop reactor, the reaction temperature will generally be in the range 60 to 110 °C (e.g. 60 to 90 °C), the reactor pressure will generally be in the range 5 to 80 bar-g (e.g.20 to 60 bar-g), and the residence time will generally be in the range 0.3 to 5 hours (e.g. 0.5 to 2 hours). The liquefied monomer is usually used as reaction medium. It is a particular feature of the invention that polymerization takes place at temperatures of at least 60 °C. For gas phase reactors, the reaction temperature used will generally be in the range 60 to 115 °C (e.g.70 to 110 °C), the reactor pressure will generally be in the range 10 to 30 bar- g (e.g.15 to 25 bar-g), and the residence time will generally be 0.5 to 8 hours (e.g.0.5 to 4 hours). The gas used will be the monomer optionally as mixture with a non-reactive gas such as nitrogen or propane. In addition to actual polymerization steps and reactors, the process can contain any additional polymerization steps, like a pre-polymerization step, and any further after reactor handling steps as known in the art. For solution polymerization, an aliphatic or aromatic solvent can be used to dissolve the monomer and the polymer, and the polymerization temperature will generally be in the range 80 to 200 °C (e.g.90 to 150 °C) Generally, the quantity of catalyst used will depend upon the nature of the catalyst, the reactor types and conditions and the properties desired for the polymer product. As is well known in the art hydrogen can be used for controlling the molecular weight of the polymer. Sensitivity: Internal The metallocene catalysts of the invention possess excellent catalyst activity and good comonomer response. The catalysts are also able to provide polymers of high weight average molecular weight Mw and narrow polydispersity Mw / Mn. Moreover, the random copolymerization behavior of metallocene catalysts of the invention shows a reduced tendency of chain transfer to ethylene. It is a feature of the invention that the claimed catalysts enable the formation of propylene polymers with high molecular weight. These features can be achieved at commercially interesting polymerization temperatures, e.g.60 °C or more, such as from 60 °C to 90 °C. The polydispersity index (Mw / Mn) of the polymers depends on the polymerization conditions in each reactor, and can be between 2.0 and 7.0. In a particular embodiment, the propylene polymers obtained using the catalysts of the invention have a narrow polydispersity index (Mw / Mn), between 2.0 and 4.0. Propylene homopolymers made by catalyst system comprising the metallocenes of the invention can be made with Mw (weight average molecular weight) values in the range of 40 to 2000 kg / mol, preferably in the range of 50 to 1500 kg / mol depending on the use and amount of hydrogen used as Mw regulating agent. The catalysts of the invention enable the formation of polypropylene homopolymers with high melting points. In a preferred embodiment the propylene homopolymer formed by the process of the invention has a melting point of more than 155 °C, preferably more than 157 °C. Propylene homopolymers having melting points up to 158 °C, or even up to 160 °C, are possible. Propylene copolymers with ethylene or with C4-C10 alpha olefin comonomers made by the metallocenes of the invention can be made with high productivity and low solubles. The polymers made by the catalysts of the description are useful in all kinds of end articles such as pipes, films (cast, blown or BOPP films, such as for example BOPP for capacitor film), fibers, moulded articles (e.g. injection moulded, blow moulded, rotomoulded articles), extrusion coatings and so on. The invention will now be illustrated by reference to the following non-limiting Examples. Sensitivity: Internal EXPERIMENTAL Measurement methods Al, B and Zr determination (ICP-method) In a glovebox, an aliquot of the catalyst (ca.40 mg) was weighed into glass weighting boat using analytical balance. The sample was then allowed to be exposed to air overnight while being placed in a steel secondary container equipped with an air intake. Then 5 mL of concentrated (65 %) nitric acid was used to rinse the content of the boat into the Xpress microwave oven vessel (20 mL). A sample was then subjected to a microwave-assisted digestion using MARS 6 laboratory microwave unit over 35 minutes at 150 °C. The digested sample was allowed to cool down for at least 4 h and then was transferred into a glass volumetric glass flask of 100 mL volume. Standard solutions containing 1000 mg / L Y and Rh (0.4 mL) were added. The flask was then filled up with distilled water and shaken well. The solution was filtered through 0.45 µm Nylon syringe filters and then subjected to analysis using Thermo iCAP 6300 ICP-OES and iTEVA software. The instrument was calibrated for Al, B, Hf, Mg, Ti and Zr using a blank (a solution of 5 % HNO3) and six standards of 0.005 mg / L, 0.01 mg / L, 0.1 mg / L, 1 mg / L, 10 mg / L and 100 mg / L of Al, B, Hf, Mg, Ti and Zr in solutions of 5 % HNO3 distilled water. However, not every calibration point was used for each wavelength. Each calibration solution contained 4 mg / L of Y and Rh standards. Al 394.401 nm was calibrated using the following calibration points: blank, 0.1 mg / L, 1 mg / L, 10 mg / L and 100 mg / L. Al 167.079 nm was calibrated as Al 394.401 nm excluding 100 mg / L and Zr 339.198 nm using the standards of blank, 0.01 mg / L, 0.1 mg / L, 1 mg / L, 10 mg / L and 100 mg / L. Curvilinear fitting and 1 / concentration weighting was used for the calibration curves. Immediately before analysis the calibration was verified and adjusted (instrument reslope function) using the blank and a 10 mg / L Al, B, Hf, Mg, Ti and Zr standard which had 4 mg / L Y and Rh. A quality control sample (QC: 1 mg / L Al, Au, Be, Hg & Se; 2 mg / L Hf & Zr, 2.5 mg / L As, B, Cd, Co, Cr, Mo, Ni, P, Sb, Sn & V; 4 mg / L Rh & Y; 5 mg / L Ca, K, Mg, Mn, Na & Ti; 10 mg / L Cu, Pb and Zn; 25 mg / L Fe and 37.5 mg / L Ca in a solution of 5 % HNO3 in distilled water) was run to confirm the reslope for Al, B, Hf, Mg, Ti and Zr. The QC sample was also run at the end of a scheduled analysis set. The content for Zr was monitored using Zr 339.198 nm {99} line. The content of aluminium was monitored via the 167.079 nm {502} line, when Al concentration in test portion was under 2 wt % and via the 394.401 nm {85} line for Al concentrations above 2 wt%. Y 371.030 nm {91} was used as internal standard for Zr 339.198 nm and Al 394.401 nm and Y 224.306 nm {450} for Al 167.079 nm. Sensitivity: Internal The content for B was monitored using B 249 nm line. The reported values were back calculated to the original catalyst sample using the original mass of the catalyst aliquot and the dilution volume. Catalyst Activity The catalyst activity was calculated based on the following formula: amount of polymer produced (kg) Catalyst Activity (kg-PP / g-Cat / h) = catalyst loading (g) × polymerization time (h) The catalyst productivity was calculated based on the following formula: amount of polymer produced (kg) Catalyst Productivity (kg-PP / g-Cat) = catalyst loading (g) Polymer powder bulk density Instruments: Electronic balance: Range from 0,1g-11000g Graduated glass cylinder: Volume = max.250ml Plastic spoon: Volume=125ml Plastic funnel: D=105mm Execution: A glass cylinder is filled up to a volume of 250 ml by pouring in the unstabilised polymer powder, using a plastic spoon and a plastic funnel. Calculation: Mass of polymer (g) / measured volume (ml) XS The xylene soluble fraction (XS) was determined in line with ISO 16152 as follows: 2.5±0.1 g of the polymer were dissolved in 250 ml o-xylene under reflux conditions and continuous stirring, under nitrogen atmosphere. After 30 minutes, the solution was allowed to cool, first for 15 minutes at ambient temperature and then maintained for 30 minutes under controlled conditions at 25 ± 0.5 °C. The solution was filtered through filter paper. For determination of the xylene soluble content, an aliquot (100 ml) of the filtrate was taken. This aliquot was evaporated in nitrogen flow and the residue dried under vacuum at 100 °C until constant weight is reached. The xylene soluble fraction (weight percent) can then be determined as follows: XS% = (100 x m1x v0) / (m0x v1), wherein m0designates the initial polymer amount (grams), m1defines the weight of residue (grams), v0defines the initial volume (milliliter) and v1defines the volume of the analyzed sample (milliliter). Sensitivity: Internal To obtain the amorphous copolymer fraction for further characterization with GPC and NMR, the remaining xylene soluble filtrate was precipitated with acetone. The precipitated polymer was filtered and dried in the vacuum oven at 100 °C to constant weight. GPC: Molecular weight averages, molecular weight distribution, and polydispersity index (Mn, Mw, Mw / Mn) The MWD and the corresponded molecular weight averages Mn, Mw, Mvand Mzof the polymer sample were determined by using Gel Permeation Chromatography (GPC) at 160°C. All samples were integrated at the low Mwend up to the 3rdlast calibration point of the calibration curve (PS = 1820 g / mol ~ 1340 g / mol PP equivalent). A high temperature GPC equipped with a suitable concentration detector (like IR5 or IR4 from PolymerChar (Valencia, Spain), an online four capillary bridge viscometer (PL-BV 400-HT), and a dual light scattering detector (PL-LS 15 / 90 light scattering detector) with a 15° and 90° angle was used. 3x Olexis and 1x Olexis Guard columns from Agilent as stationary phase and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-Di tert butyl-4-methyl-phenol) as mobile phase at 160 °C and at a constant flow rate of 1 mL / min was applied. 200 μL of sample solution were injected per analysis. All samples were prepared by dissolving 8.0 – 10.0 mg of polymer in 10 mL (at 160 °C) of stabilized TCB (same as mobile phase) for 2,5 hours at 160°C under continuous gentle shaking. The injected concentration of the polymer solution at 160 °C (c160°C) was determined in the following way. 0,8772 With: w25(polymer weight) and V25(Volume of TCB at 25°C). The column set was calibrated using universal calibration (according to ISO 16014-2:2019) with 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg / mol to 11500 kg / mol. The PS standards were dissolved at 160°C for 15 min or alternatively at room temperatures at a concentration of 0.2 mg / ml for molecular weight higher and equal 899 kg / mol and at a concentration of 1 mg / ml for molecular weight below 899 kg / mol. The conversion of the polystyrene peak molecular weight to polypropylene molecular weights is accomplished by using the Mark Houwink equation and the following Mark Houwink constants: KPS = 19 x 10-5ml / g, αPS = 0.655 KPP = 39 x 10-5ml / g, αPP = 0.725 Sensitivity: Internal A third order polynomial fit was used to fit the calibration data. All samples were prepared in the concentration range of 0.5 -1 mg / ml and dissolved at 160 °C for 3 hours under continuous gentle shaking Molecular weight averages (Mn, Mw, Mvand Mz), Molecular weight distribution (MWD) and its broadness, described by the polydispersity index PD= Mw / Mn(wherein Mnis the number average molecular weight and Mwis the weight average molecular weight) were determined using the following formulas: DSC The DSC curves and data have been produced on a DSC Q200 TA Instrument, by placing a 5-7 mg sample cut from the polymer MFR string, into a closed DSC aluminum pan, heating the sample from -10 °C to 225 °C at 10 °C / min, holding for 10 min at 225 °C, cooling from 225 °C to –30 °C, holding for 5 min at –30 °C, heating from –30 °C to 225 °C at 10 °C / min. The reported Tmvalues are those of the peak of the endothermic heat flow determined from the second heating scan. Melt Flow Rate The melt flow rate (MFR) was determined according to ISO 1133 and is indicated in g / 10 min. The MFR is an indication of the flowability, and hence the processability, of the polymer. The higher the melt flow rate, the lower the molecular weight of the polymer. The MFR was determined at 230°C and may be determined at different loadings such as 2.16 kg (MFR2) or 21.6 kg (MFR21). Sensitivity: Internal NMR Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the isotacticity and content of regio-defects of the polypropylene homopolymers. Quantitative13C{1H} NMR spectra recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C respectively. All spectra were recorded using a13C optimised 10 mm selective excitation probehead at 125°C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 1,2- tetrachloroethane-d2(TCE-d2). This setup was chosen primarily for the high resolution needed for tacticity distribution quantification (Busico, V., Cipullo, R., Prog. Polym. Sci.26 (2001) 443; Busico, V.; Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromolecules 30 (1997) 6251). Standard single-pulse excitation was employed utilising the NOE and bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson.187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 11289). A total of 6144 (6k) transients were acquired per spectra using a 3 s recycle delay. Quantitative13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts are internally referenced to the methyl signal of the isotactic pentad mmmm at 21.85 ppm. The tacticity distribution was quantified through integration of the methyl region between 23.6 and 19.7 ppm correcting for any sites not related to the stereo sequences of interest (Busico, V., Cipullo, R., Prog. Polym. Sci.26 (2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromolecules 30 (1997) 6251). The pentad isotacticity was determined through direct integration of the methyl region and reported as either the mole fraction or percentage of isotactic pentad mmmm with respect to all steric pentads i.e. [mmmm] = mmmm / sum of all steric pentads. When appropriate integrals were corrected for the presence of sites not directly associated with steric pentads. Characteristic signals corresponding to regio irregular propene insertion were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253). The presence of secondary inserted propene in the form of 2,1 erythro regio defects was indicated by the presence of the two methyl signals at 17.7 and 17.2 ppm and confirmed by the presence of other characteristic signals. The amount of 2,1 erythro regio defects was quantified using the average integral (e) of the e6 and e8 sites observed at 17.7 and 17.2 ppm respectively, i.e. e = 0.5 * (e6 + e8). Characteristic signals corresponding to other types of regio irregularity were not observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, Sensitivity: Internal F., Chem. Rev. 2000, 100, 1253). The amount of primary inserted propene (p) was quantified based on the integral of all signals in the methyl region (CH3) from 23.6 to 19.7 ppm paying attention to correct for other species included in the integral not related to primary insertion and for primary insertion signals excluded from this region such that p = CH3 + 2*e. The relative content of a specific type of regio defect was reported as the mole fraction or percentage of said regio defect with respect all observed forms of propene insertion i.e. sum of all primary (1,2), secondary (2,1) and tertiary (3,1) inserted propene units, e.g. [21e] = e / ( p + e + t + i ). The total amount of secondary inserted propene in the form of 2,1-erythro or 2,1-threo regio defects was quantified as sum of all said regio irregular units, i.e.

[0021] = [21e] + [21t]. Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the ethylene content and the isotacticity of the copolymers. Quantitative13C{1H} NMR spectra were recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C respectively. All spectra were recorded using a13C optimised 10 mm extended temperature probehead at 125°C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) along with chromium-(III)-acetylacetonate (Cr(acac)3) resulting in a 65 mM solution of relaxation agent in solvent as described in G. Singh, A. Kothari, V. Gupta, Polymer Testing 2009, 28(5), 475. To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single- pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme as described in Z. Zhou, R. Kuemmerle, X. Qiu, D. Redwine, R. Cong, A. Taha, D. Baugh, B. Winniford, J. Mag. Reson.187 (2007) 225 and V. Busico, P. Carbonniere, R. Cipullo, C. Pellecchia, J. Severn, G. Talarico, Macromol. Rapid Commun.2007, 28, 1128. A total of 6144 (6k) transients were acquired per spectra. Quantitative13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Sensitivity: Internal With characteristic signals corresponding to 2,1 erythro regiodefects observed (as described in L. Resconi, L. Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 2000, 100 (4), 1253, in Cheng, H. N., Macromolecules 1984, 17, 1950, and in W-J. Wang and S. Zhu, Macromolecules 2000, 33, 1157) the correction for the influence of the regiodefects on determined properties was required. Characteristic signals corresponding to other types of regiodefects were not observed. Characteristic signals corresponding to the incorporation of ethylene were observed (as described in Cheng, H. N., Macromolecules 1984, 17, 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer: fE = ( E / ( P + E ) The comonomer fraction was quantified using the method of W-J. Wang and S. Zhu, Macromolecules 2000, 33, 1157, through integration of multiple signals across the whole spectral region in the13C{1H} spectra. This method was chosen for its robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents. The mole percent comonomer incorporation was calculated from the mole fraction: E [mol%] = 100 * fE The weight percent comonomer incorporation was calculated from the mole fraction: E [wt%] = 100 * ( fE * 28.06 ) / ( (fE * 28.06) + ((1-fE) * 42.08) ) The isotacticity of the copolymer was determined according to known methods, for example as described in Macromolecules 2005, vol.38, pp.3054-3059. The crystalline (CF) and soluble fractions (SF) of the heterophasic propylene resins as well as the comonomer content and intrinsic viscosities of the respective fractions were analysed by the Crystex method. The crystalline and amorphous fractions are separated through temperature cycles of dissolution at 160°C, crystallization at 40°C and re- dissolution in 1,2,4-trichlorobenzene (1,2,4-TCB) at 160°C. Quantification of SF and CF and determination of ethylene content (C2) are achieved by means of an infrared detector (IR4) and an online 2-capillary viscometer is used for determination of the intrinsic viscosity (iV). IR4 detector is multiple wavelength detector detecting IR absorbance at two different bands (CH3 and CH2) for the determination of the concentration and the ethylene content Sensitivity: Internal in ethylene-propylene copolymers. IR4 detector is calibrated with series of EP copolymers with known ethylene content in the range of 2 wt.-% to 69 wt.-% (determined by 13C- NMR). Amount of Soluble fraction (SF) and Crystalline Fraction (CF) are correlated through the XS calibration to the “Xylene Soluble” (XS) quantity and respectively Xylene Insoluble (XI) fractions, determined according to standard gravimetric method as per ISO16152 (2005). XS calibration is achieved by testing various EP copolymers with XS content in the range 2-31 wt%. Intrinsic viscosity (iV) of the parent EP copolymer and its soluble and crystalline fractions are determined with a use of an online 2-capillary viscometer and are correlated to corresponding iV determined in decalin according to ISO 1628-3 (2010). Calibration is achieved with several commercial EP PP copolymers with iV = 2-4 dL / g. A sample of the PP composition to be analysed is weighed out in concentrations of 10mg / ml to 20mg / ml. After automated filling of the vial with 1,2,4-TCB containing 250 mg / l 2,6-tert-butyl-4-methylphenol (BHT) as antioxidant, the sample is dissolved at 160°C until complete dissolution is achieved, usually for 60 min, with constant stirring of 800rpm. A defined volume of the sample solution is injected into the column filled with inert support where the crystallization of the sample and separation of the soluble fraction from the crystalline part is taking place. This process is repeated two times. During the first injection the whole sample is measured at elevated temperature, determining the iV[dl / g] and the C2[wt%] of the PP composition. During the second injection the soluble fraction (at low temperature) and the crystalline fraction (at elevated temperature) with the crystallization cycle are determined (wt% SF, wt% C2, iV). Metallocene synthesis Synthesis of CM1 CM1 was prepared as described in WO2019179959, MC-2. Synthesis of CM2 CM2, was prepared as described in WO2005058916, metallocene example 1. Sensitivity: Internal Synthesis of IM1 Isopropylmalonic acid A solution of 125 g of potassium hydroxide in 1000 cm3of water was added to a solution of 110.0 g (544 mmol) of diethyl isopropylmalonate in 500 ml of methanol. The resulting mixture was refluxed for 5 h, then ethanol and methanol were distilled off. Then 1000 cm3of water was added, and the obtained mixture was acidified by 12 M HCl to pH 1.0. Isopropylmalonic acid was extracted with 4 ^500 ml of ether. The combined extract was evaporated to dryness, and the residue was dried in vacuum. This procedure gave 76.4 g (96.1%) of isopropylmalonic acid as white solid.1H NMR (CDCl3): δ 9.72 (br.s, 2H), 3.24 (d, J = 8.3 Hz, 1H), 2.48-2.34 (m, 1H), 1.07 (d, J = 6.8 Hz, 6H). 2-Isopropylacrylic acid Diethylamine (62.4 ml, 44.3 g, 0.606 mol) was added dropwise at 5 °C to a solution of isopropylmalonic acid (76.4 g, 523 mmol) in 750 ml of ethyl acetate. Paraform (22.1 g, 0.736 mol) was added to the obtained suspension. The resulting mixture was refluxed for 5 h, then cooled to 5 °C, and 350 ml of ether and 1000 cm3of 2 M HCl were added. After mixing, the organic layer was separated, the aqueous layer was additionally extracted with 2 ^500 ml of ether. The combined organic phase was dried over Na2SO4 and then evaporated to dryness. The residue was purified by vacuum distillation to give 2- isopropylacrylic acid, bp 65 °C / 4 mm Hg. Yield 57.0 g (95.5%) of a colorless liquid.1H NMR (CDCl3): δ 12.45 (br.s, 1H), 6.30 (s, 1H), 5.65 (t, 1H), 2.81 (septd, J = 6.9 Hz, J = 0.9 Hz, 1H), 1.11 (d, J = 6.9 Hz, 6H).13C NMR (CDCl3): δ 173.30, 146.47, 124.31, 28.94, 21.76. Sensitivity: Internal 6-tert-Butyl-5-methoxy-2-isopropylindan-1-one 114.1 g (1.0 mol) of 2-isopropylacrylic acid was added to Eaton's reagent obtained from 220 g of P4O10 and 1120 ml of MeSO3H at 50 °C. 131.2 g (0.8 mol) of 1-tert-butyl-2- methoxybenzene was added dropwise to this mixture with vigorous stirring for ca.1 h at 50-53 °C (water bath temperature). The resulting mixture was stirred for 1 h at this temperature, then cooled to room temperature, and poured on a mixture of 1.5 liter of cold water and 3 kg of ice. The crude product was extracted with 3 ^600 ml of dichloromethane. The combined organic phase was washed by aqueous K2CO3, dried over K2CO3, filtered through a short pad of silica gel 60 (40-63 µm) and then evaporated to dryness. The residue was purified by vacuum distillation to give 193.8 g (93.0 %, ca.95% purity) of 6- tert-butyl-5-methoxy-2-isopropylindan-1-one as a yellowish oil (bp 150-190oC / 4 mm Hg).1H NMR (CDCl3): δ 7.66 (s, 1H), 6.89 (s, 1H), 3.93 (s, 3H), 3.04 (dd, J = 17.4 Hz, J = 8.0 Hz, 1H), 2.84 (dd, J = 17.4 Hz, J = 3.8 Hz, 1H), 2.67-2.60 (m, 1H), 2.48-2.34 (m, 1H), 1.37 (s, 9H), 1.05 (d, J = 6.9 Hz, 3H), 0.77 (d, J = 6.9 Hz, 3H).13C NMR (CDCl3): δ 207.45, 164.44, 155.10, 138.54, 130.07, 121.69, 107.64, 55.14, 53.20, 35.00, 29.54, 28.87, 27.65, 20.96, 17.00. 4-Bromo-6-tert-butyl-2-isopropyl-5-methoxyindan-1-one Bromine (20.8 ml, 64.9 g, 405.9 mmol) was added dropwise over 5 min to a mixture of 97.0 g (0.372 mol) of 6-tert-butyl-2-isopropyl-5-methoxyindan-1-one, 113.2 g of sodium acetate, 3.0 g ofnBu4NI, 310 ml of dichloromethane, and 645 ml of water with vigorous stirring at 5 °C. This mixture was stirred at 5 °C for 2 h, then a solution of 52.2 g of sodium acetate in 290 ml of water was added followed by addition of 10.8 ml (33.7 g, 210.8 mmol) of bromine. The resulting mixture was additionally stirred for 1 h at this temperature and then washed by aqueous Na2SO3to remove excess bromine. The crude product was extracted by 3 ^250 ml of dichloromethane. The combined organic extract was dried over Sensitivity: Internal K2CO3, evaporated to dryness, and the residue was dried in vacuum. This procedure gave 124.84 g (98.9%, ca. 95% purity) of a yellowish oil which was used without further purification.1H NMR (CDCl3): δ 7.68 (s, 1H), 4.04 (s, 3H), 3.04 (dd, J = 17.9 Hz, J = 8.1 Hz, 1H), 2.80 (dd, J = 17.9 Hz, J = 3.9 Hz, 1H), 2.71-2.64 (m, 1H), 2.49-2.35 (m, 1H), 1.40 (s, 9H), 1.08 (d, J = 6.9 Hz, 3H), 0.80 (d, J = 6.8 Hz, 3H).13C NMR (CDCl3): δ 207.21, 162.59, 154.47, 145.24, 133.82, 121.03, 116.56, 61.54, 53.32, 35.56, 30.54, 29.41, 28.94, 20.78, 17.17. 6-tert-Butyl-2-isopropyl-5-methoxy-4-(3,5-dimethylphenyl)-indan-1-one A mixture of 124.84 g (368.0 mmol) of 4-bromo-6-tert-butyl-2-isopropyl-5-methoxyindan- 1-one, 69.7 g (464.7 mmol, 1.26 equiv.) of 3,5-Me2C6H3B(OH)2, 1.9 g (3.72 mmol, 1 mol. %) of Pd(PtBu3)2, 118.3 g of Na2CO3, 600 ml of 2-methyltetrahydrofurane and 540 ml of water was refluxed for 6 h. Then, 500 ml of water was added, the organic layer was separated, and the aqueous layer was extracted with 300 ml of dichloromethane. The combined organic extract was dried over K2CO3 and then evaporated to dryness to give slightly yellowish solid mass. The product was isolated by flash-chromatography on silica gel 60 (40-63 µm, eluent: hexanes-dichloromethane = 1:1 and then 1:5, vol.). Yield 121.55 g (90.6%, purity ca.95%) of a yellowish crystalline material.1H NMR (CDCl3): δ 7.71 (s, 1H), 7.04 (s, 1H), 7.03 (s, 2H), 3.31 (s, 3H), 2.87 (dd, J = 18.5 Hz, J = 8.8 Hz, 1H), 2.65-2.54 (dd and m, 2H), 2.43-2.34 (s and m, 7H), 1.42 (s, 9H), 0.99 (d, J = 6.9 Hz, 3H), 0.77 (d, J = 6.8 Hz, 3H).13C NMR (CDCl3): δ 208.19, 163.34, 153.44, 143.11, 138.08, 136.33, 132.64, 132.12, 129.08, 127.20, 120.93, 77.00, 60.46, 53.37, 35.33, 30.50, 28.88, 27.38, 21.39, 20.90, 17.25. Sensitivity: Internal 5-tert-Butyl-2-isopropyl-6-methoxy-7-(3,5-dimethylphenyl)-1H-indene NaBH4(18.9 g, 0.5 mol, 1.5 equiv.) was added to a solution of 121.55 g (333.45 mmol) of 6-tert-butyl-2-isopropyl-5-methoxy-4-(3,5-dimethylphenyl)-indan-1-one in 600 ml of THF cooled to 5 °C. MeOH (300 ml) was added dropwise to this mixture over ca.5 h at 5 °C, and the resulting mixture was stirred overnight at room temperature. Then, this mixture was evaporated to dryness, 1000 ml of dichloromethane and 1000 ml water were added to the residue, and the so obtained mixture was acidified with 2 M HCl to pH~6.5. The organic layer was separated, the aqueous layer was additionally extracted with 100 ml of dichloromethane. The combined organic phase was passed through a pad (~30 ml) of silica gel 60 (40-63 µm; eluent: dichloromethane) to get rid of most of the palladium black. The obtained elute was evaporated to dryness to give a grey solid mass. To a solution of this mass in 1000 ml of toluene 1.0 g of TsOH was added. This mixture was refluxed with Dean-Stark head for 10 min and then cooled to room temperature using water bath. The formed solution was washed with 10% Na2CO3, the organic layer was separated, the aqueous layer was extracted with 300 ml of dichloromethane. The combined organic phase was dried over K2CO3 and then evaporated to dryness. The crude product was purified by flash chromatography on silica gel 60 (40-63 µm, hexanes-dichloromethane = 5:1) followed by recrystallization from n-hexane (hot→ –30 °C). This procedure gave 96.93 g (83.4%) of pure 5-tert-butyl-7-(3,5-dimethylphenyl)-2-isopropyl-6-methoxy-1H-indene.1H NMR (CDCl3): δ 7.24 (s, 1H), 7.09 (s, 2H), 6.99 (s, 1H), 6.46 (m, 1H), 3.24 (s, 3H), 3.15 (m, 2H), 2.68 (sept, J = 6.8 Hz, 1H), 2.37 (s, 6H), 1.43 (s, 9H), 1.14 (d, J = 6.8 Hz, 6H).13C NMR (CDCl3): δ 156.43, 154.33, 141.34, 140.95, 140.23, 138.29, 137.69, 131.99, 128.49, 127.22, 123.86, 117.32, 60.67, 39.15, 35.13, 31.00, 30.04, 22.64, 21.44. Sensitivity: Internal [6-tert-butyl-4-(3,5-dimethylphenyl)-2-isopropyl-5-methoxy-1H-inden-1-yl] chlorodimethylsilane nBuLi in hexanes (2.5 M, 8.0 ml, 20.0 mmol) was added in one portion to a solution of 5- tert-butyl-7-(3,5-dimethylphenyl)-2-isopropyl-6-methoxy-1H-indene (6.97 g, 20.0 mmol) in 200 ml of ether cooled to –50 °C. This mixture was stirred overnight at room temperature, then the resulting yellow suspension was cooled to –50 °C, then dichlorodimethylsilane (12.1 ml, 12.95 g, 100.3 mmol, 5.02 equiv.) was added in one portion followed by 5 ml of THF. The resulting mixture was stirred overnight at room temperature, then filtered through a glass frit (G3), and the filter cake was washed with 2 ^50 ml of toluene. The combined filtrate was evaporated to dryness to give [6-tert-butyl-4-(3,5-dimethylphenyl)-2-isopropyl- 5-methoxy-1H-inden-1-yl]chlorodimethylsilane as a yellowish thick oil which was used without further purification.1H NMR (CDCl3): δ 7.40 (s, 1H), 7.10 (br.s, 2H), 7.00 (m, 1H), 6.44 (s, 1H), 3.76 (s, 1H), 3.23 (s, 3H), 2.89 (sept.d, J = 6.8 Hz, J = 1.3 Hz, 1H), 2.39 (s, 6H), 1.43 (s, 9H), 1.20 (d, J = 6.7 Hz, 3H), 1.12 (d, J = 6.9 Hz, 3H), 0.43 (s, 3H), 0.12 (s, 3H).13C NMR (CDCl3): δ 157.53, 155.85, 143.40, 137.91, 137.60, 136.43, 128.33, 127.92, 127.89, 122.52, 121.06, 60.45, 47.72, 35.16, 31.16, 29.45, 24.43, 21.45, 21.17, 1.35, -0.77. Sensitivity: Internal [4,8-Bis(3,5-dimethylphenyl)-2-methyl-1,5,6,7-tetrahydro-s-indacen-1-yl][6-tert-butyl-4- (3,5-dimethylphenyl)-5-methoxy-2-isopropyl-1H-inden-1-yl]dimethylsilane nBuLi in hexanes (2.5 M, 8.0 ml, 20.0 mmol) was added in one portion to a suspension of 4,8-di(3,5-dimethylphenyl)-6-methyl-1,2,3,5-tetrahydro-s-indacene (7.57 g, 20.0 mmol) in a mixture of 120 ml of ether and 25 ml of THF, cooled to –50 °C. The resulting mixture was stirred overnight at room temperature, then the so obtained light-orange solution containing a large amount of orange precipitate was cooled to –50 °C, and 200 mg of CuCN was added. The obtained mixture was stirred for 0.5 h at –25 °C, then a solution of ca. 20.0 mmol of [6-tert-butyl-4-(3,5-dimethylphenyl)-2-isopropyl-5-methoxy-1H-inden-1- yl]chlorodimethylsilane (prepared above) in 200 ml of Et2O was added in one portion. This mixture was stirred overnight at room temperature, then filtered through a pad of silica gel 60 (40-63 µm), which was additionally washed with 2 ^50 ml of Et2O. The combined organic elute was evaporated to dryness, and the residue was dried under vacuum at elevated temperature to give 15.58 g (99.5% of ca.85% purity) of the title product (ca.63:37 mixture of the stereoisomers) as a slightly yellowish solid glass which was used without further purification. Sensitivity: Internal Anti-dimethylsilanediyl[2-methyl-4,8-di(3,5-dimethylphenyl)-1,5,6,7-tetrahydro-s-indacen- 1-yl][2-isopropyl-4-(3,5-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride (MC-IE1) nBuLi in hexanes (2.5 M, 14.8 ml, 37.0 mmol) was added in one portion at room temperature to a yellowish solution of [4,8-bis(3,5-dimethylphenyl)-2-methyl-1,5,6,7- tetrahydro-s-indacen-1-yl][6-tert-butyl-4-(3,5-dimethylphenyl)-5-methoxy-2-isopropyl-1H- inden-1-yl]dimethylsilane (14.46 g, ca.18.46 mmol) in 95 ml ofnBu2O. This mixture was stirred overnight at room temperature, then the resulting red solution was cooled to 0 °C in an ice-bath, then ZrCl4(4.3 g, 18.45 mmol) was added. The reaction mixture was stirred for 24 h at room temperature to give orange-red solution with precipitate of LiCl. This mixture was evaporated to dryness (to the state of red foam), and the residue was treated with 100 ml of warm toluene. The obtained suspension was filtered through glass frit (G4), the filter cake was washed with 2 ^20 ml of warm toluene. The filtrate was evaporated to ca.20 ml, then 30 ml of n-hexane was added to this solution. The yellow solid precipitated from this solution overnight at room temperature was collected and dried under vacuum. This procedure gave 3.3 g of anti-complex. The mother liquor was evaporated to the state of oil, and the residue was dissolved in 30 ml of n-hexane. The yellow powder precipitated from this solution overnight at room temperature was collected and dried under vacuum. This procedure gave 3.4 g of anti-complex. The mother liquor was evaporated to dryness, and the residue was dissolved in 30 ml of n-hexane. Yellow powder precipitated from this solution overnight at –25 °C was collected and dried under vacuum. This procedure gave 1.55 g of anti-complex. The mother liquor was again evaporated to dryness, and the residue was dissolved in 20 ml of n-pentane. Yellow powder precipitated from this solution overnight at –25 °C was collected and dried under vacuum. This procedure gave 0.85 g of Sensitivity: Internal anti-complex. Thus, the total yield of anti-dimethylsilanediyl[2-methyl-4,8-di(3,5- dimethylphenyl)-1,5,6,7-tetrahydro-s-indacen-1-yl][2-isopropyl-4-(3,5-dimethylphenyl)-5- methoxy-6-tert-butylinden-1-yl]zirconium dichloride isolated in this synthesis was 9.1 g (52.3%). Anal. calc. for C56H64Cl2OSiZr: C, 71.30; H, 6.84. Found: C, 71.38; H, 7.00.1H NMR (CDCl3): δ 7.42 (s, 1H), 7.11 (s, 1H), 6.99 (s, 2H), 6.97 (s, 1H), 6.93 (s, 1H), 6.88 (s, 1H), 6.61 (s, 1H), 7.8-6.7 (very br.s, 4H), 3.36 (s, 3H), 3.21-3.04 (m, 2H), 3.04-2.84 (m, 2H), 2.54-2.40 (m, 1H), 2.43, 2.36, 2.35 and 2.28 (4s, sum 21H), 2.05-1.92 (m, 1H), 1.80- 1.64 (m, 1H), 1.34 (s, 9H), 1.16 (s, 3H), 1.08 (d, J = 6.4 Hz, 3H), 0.84 (d, J = 6.6 Hz, 3H), -0.14 (s, 3H).13C NMR (CDCl3): δ 159.89, 146.50, 144.76, 144.43, 142.85, 141.58, 138.34, 138.15, 137.32, 136.84, 135.47, 132.74, 132.31, 132.19, 131.26, 129.38, 129.16, 128.97, 128.81, 128.74, 127.60, 126.90, 125.09, 121.69, 121.25, 116.29, 83.13, 81.42, 62.40, 35.67, 33.93, 32.61, 30.43, 29.57, 28.91, 26.04, 21.52, 21.41, 21.25, 20.41, 20.05, 4.07, 3.05. Synthesis of IM2 [6-tert-butyl-4-(3,5-dimethylphenyl)-5-methoxy-2-methyl-1H-inden-1-yl] chlorodimethylsilane nBuLi in hexanes (2.43 M, 14.6 ml, 35.5 mmol) was added in one portion to a solution of 5-tert-butyl-7-(3,5-dimethylphenyl)-6-methoxy-2-methyl-1H-indene (11.3 g, 35.3 mmol) in 200 ml of ether cooled to –50 °C. The resulting orange solution was stirred overnight at room temperature, then the obtained orange solution containing a yellowish precipitate was cooled to –78 °C (the precipitate almost completely disappeared), and dichlorodimethylsilane (22.8 g, 177 mmol, 5 equiv) was added in one portion. The formed solution was warmed to room temperature and stirred overnight at room temperature. The resulting mixture was filtered through glass frit (G4). The precipitate was additionally washed by 2×10 ml of ether. The combined filtrate was evaporated to dryness to give the title material as slightly orange oil which was used without further purification. Sensitivity: Internal 2-Isopropylacryloyl chloride One drop of DMF was added to a solution of 2-isopropylacrylic acid (96.4 g, 845 mmol) in 750 ml of dichloromethane cooled in an ice bath. Oxalyl chloride (118 g, 930 mmol) was added dropwise over 1 h to this solution, then the reaction mixture was stirred overnight at room temperature. The reaction mixture was concentrated, and the residue was distilled under vacuum to give 86.0 g (76.8%) of 2-isopropylacryloyl chloride as a colorless liquid, b.p.70 °C / 100 mbar.1H NMR (CDCl3): δ 6.58 (s, 1H), 6.03 (d, J = 1.1 Hz, 1H), 2.84 (septet d, J = 6.9 Hz, J = 1.1 Hz, 1H), 1.13 (d, J = 6.9 Hz, 6H).13C NMR (CDCl3): δ 168.63, 151.46, 130.81, 30.34, 21.66. 2-Isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one A mixture of 2-isopropylacryloyl chloride (86.0 g, 649 mmol) and indane (77.0 g, 652 mmol) was added dropwise over 15 min to a suspension of AlCl3(216 g, 1.62 mol) in 1200 ml of dichloromethane kept cooled at 0 °C. The cooling bath was then removed, then this solution was stirred overnight at room temperature. The reaction mixture was poured into 2 kg of crushed ice, the organic phase was separated, and the aqueous phase was extracted with 3 ^500 ml of dichloromethane. The combined organic extract was washed with aqueous K2CO3, dried over K2CO3, passed through a short pad of silica gel 60 (40-63 µm). The elute was evaporated to dryness to give a red oil. This oil was distilled under vacuum to give 103.75 g (ca.75%, purity ca.75%) of a slightly yellowish oil, b.p.127°C / 3 mm Hg. The so obtained 2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one was used without further purification.1H NMR (CDCl3): δ 7.55 (s, 1H), 7.28 (s, 1H), 3.11-3.00 (m, 1H), 3.00-2.81 (m, 5H), 2.69- 2.62 (m, 1H), 2.48-2.34 (m, 1H), 2.16-2.05 (m, 2H), 1.04 (d, J = 7.0 Hz, 3H), 0.77 (d, J = 6.9 Hz, 3H).13C NMR (CDCl3): δ 208.31, 153.31, 152.75, 143.89, 136.34, 121.88, 118.70, 53.39, 32.96, 31.90, 28.93, 27.70, 25.67, 20.80, 17.03. Sensitivity: Internal 4,8-Dibromo-2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one A solution of 2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one (as prepared above, 103.75 g, ca.0.45 mol, ca.75% purity) in 200 ml of dichloromethane was added dropwise over 15 min to a suspension of 150.0 g (1.13 mol, 2.5 eq.) of AlCl3 in 500 ml of dichloromethane at –10 °C. The reaction mixture was stirred for 10 min at this temperature, then bromine (47.5 ml, 147.4 g, 922 mmol, 2.05 equiv.) was added dropwise over 1 h. The resulting mixture was stirred overnight at room temperature and then poured onto 2000 cm3of crushed ice. The organic layer was separated, the aqueous layer was extracted with 3 ^300 ml of dichloromethane. The combined organic extract was washed with aqueous K2CO3, dried over K2CO3, passed through a short pad of silica gel 60 (40-63 µm), and the obtained elute was evaporated to dryness to give a dark-red oil. The crude product was roughly purified by flash chromatography on silica gel 60 (40-63 µm, eluent: hexanes: dichloromethane = 2:1, then, 1:1, vol.). This procedure gave 155.1 g (ca.93%, ca.85% purity) of 4,8-dibromo-2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one that was used without further purification.1H NMR (CDCl3): δ 3.12-3.00 (m, 4H), 2.95 (dd, J = 18.5 Hz, J = 8.9 Hz, 1H), 2.75-2.63 (m, 2H), 2.43-2.32 (m, 1H), 2.14 (quint, J = 7.7 Hz, 2H), 1.04 (d, J = 7.0 Hz, 3H), 0.77 (d, J = 6.9 Hz, 3H).13C NMR (CDCl3): δ 204.74, 155.18, 152.41, 146.81, 134.78, 117.77, 114.91, 54.13, 35.61, 34.57, 29.10, 28.36, 23.16, 20.62, 17.22. 4,8-Bis(3,5-dimethylphenyl)-2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one A mixture of 68.31 g (ca.184 mmol) of 4,8-dibromo-2-isopropyl-3,5,6,7-tetrahydro-s- indacen-1(2H)-one (purity ca. 85%), 68.84 g (459.0 mmol, 2.5 equiv.) of 3,5- dimethylphenylboronic acid, 2.0 g of Pd(PtBu3)2, 117 g of Na2CO3, 500 ml of 2- methyltetrahydrofurane, and 525 ml of water was refluxed for 6 h. Then 500 ml of water Sensitivity: Internal was added, the organic layer was separated, and the aqueous layer was extracted with 300 ml of dichloromethane. The combined organic extract was dried over K2CO3and then evaporated to dryness to give a brown solid mass. The product was isolated by flash- chromatography on silica gel 60 (40-63 µm, eluent: hexanes-dichloromethane = 1:1, vol.). The elute was evaporated to dryness followed by trituration of the residue with 100 ml of n-hexane. The obtained suspension was filter through glass frit (G3), and white precipitate was washed with 2 ^25 ml of n-hexane and then dried in vacuum. Yield 53.22 g (68.6%) of 4,8-bis(3,5-dimethylphenyl)-2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one.1H NMR (CDCl3): δ 7.04 (s, 1H), 6.99 (s, 1H), 6.96 (s, 2H), 6.91 (s, 2H), 2.97-2.54 (m, 7H), 2.40 (s, 6H), 2.36 (s, 6H), 2.36-2.26 (m, 1H), 2.07-1.88 (m, 2H), 0.95 (d, J = 6.9 Hz, 3H), 0.74 (d, J = 6.8 Hz, 3H).13C NMR (CDCl3): δ 207.23, 152.27, 149.85, 143.45, 138.26, 137.93, 137.26, 136.84, 135.69, 135.40, 133.01, 128.92, 126.74, 126.47, 53.87, 33.01, 31.94, 28.73, 26.61, 25.61, 21.46, 21.42, 20.88, 17.18. 4,8-Bis(3,5-dimethylphenyl)-6-isopropyl-1,2,3,5-tetrahydro-s-indacene 1000 ml of methanol was added dropwise over 5 h at 0-5 °C to a mixture cooled in an ice bath of 4,8-bis(3,5-dimethylphenyl)-2-isopropyl-3,5,6,7-tetrahydro-s-indacen-1(2H)-one (100.4 g, 237.6 mmol) and NaBH4 (40.0 g, 1.06 mmol) in 2000 ml of THF. The obtained mixture was stirred overnight at room temperature and then evaporated to dryness.1000 ml of dichloromethane and 1000 ml of water were added to the residue, and thus obtained mixture was acidified by 2 M HCl to pH~6.5. The organic layer was separated, the aqueous layer was additionally extracted with 2 ^300 ml of dichloromethane. The combined organic extract was dried over Na2SO4 and evaporated to dryness to give a white solid mass. To a solution of this solid mass in 900 ml of toluene, preheated to ca.60 °C, 1.0 g of TsOH was added. This mixture was refluxed with Dean-Stark head for 10 min. Then, the reaction mixture was quickly cooled to room temperature using an ice-water bath. The formed solution was washed with 10% Na2CO3, the organic layer was separated, the aqueous layer was extracted with 250 ml of dichloromethane. The combined organic extract was dried over K2CO3 and then evaporated to dryness. The crude product was purified by flash Sensitivity: Internal chromatography on silica gel 60 (40-63 µm, hexanes-dichloromethane = 10:1) followed by crystallization of the crude product from n-hexane at –25 °C to give 93.31 g (96.6%) of 4,8- bis(3,5-dimethylphenyl)-6-isopropyl-1,2,3,5-tetrahydro-s-indacene as a colorless crystals.1H NMR (CDCl3): δ 7.05 (s, 2H), 7.04 (s, 2H), 7.00 (s, 1H), 6.99 (s, 1H), 6.44 (m, 1H), 3.26 (s, 2H), 2.88 (t, J =7.3 Hz, 2H), 2.82 (t, J =7.3 Hz, 2H), 2.68 (septet, J =6.7 Hz, 1H), 2.38 (2s, sum 12H), 1.98 (quin, J =7.3 Hz, 2H), 1.11 (d, J =6.9 Hz, 6H).13C NMR (CDCl3): δ 156.46, 142.39, 140.92, 140.24, 140.05, 139.80, 138.53, 137.60, 137.42, 133.59, 129.89, 128.42, 128.19, 127.33, 126.61, 123.21, 38.65, 32.80, 32.52, 30.23, 26.11, 22.63, 21.45. [4,8-Bis(3,5-dimethylphenyl)-2-isopropyl-1,5,6,7-tetrahydro-s-indacen-1-yl][6-tert-butyl-4- (3,5-dimethylphenyl)-5-methoxy-2-methyl-1H-inden-1-yl]dimethylsilane nBuLi in hexanes (2.5 M, 7.2 ml, 18.0 mmol) was added in one portion at –50 °C to a solution of 4,8-bis(3,5-dimethylphenyl)-6-isopropyl-1,2,3,5-tetrahydro-s-indacene (7.3 g, 17.95 mmol) in 100 ml of ether. This mixture was stirred overnight at room temperature, then the resulting greenish-yellow suspension was cooled to –50 °C, then 150 mg of CuCN was added. The obtained mixture was stirred for 0.5 h at –25 °C, then a solution of [6-tert- butyl-4-(3,5-dimethylphenyl)-5-methoxy-2-methyl-1H-inden-1-yl]chlorodimethylsilane (7.5 g, 18.16 mmol) in a mixture of 125 ml of ether and 25 ml of THF was added in one portion. This mixture was stirred for 3 h at room temperature, then filtered through a pad of silica gel 60 (40-63 µm) that was additionally washed with 2 ^50 ml of hexane. The combined organic elute was evaporated to dryness, and the residue was dried under vacuum at elevated temperature to give 14.23 g (ca.100%, purity ca.90%) of the title product (a ca. 1:1 mixture of the stereoisomers) as a slightly yellow glass which was used without further purification. Sensitivity: Internal Anti-dimethylsilanediyl[2-isopropyl-4,8-bis(3,5-dimethylphenyl)-1,5,6,7-tetrahydro-s- indacen-1-yl][2-methyl-4-(3,5-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride (MC-IE2) nBuLi in hexanes (2.5 M, 13.1 ml, 32.75 mmol) was added in one portion to a solution of [4,8-bis(3,5-dimethylphenyl)-2-isopropyl-1,5,6,7-tetrahydro-s-indacen-1-yl][6-tert-butyl-4- (3,5-dimethylphenyl)-5-methoxy-2-methyl-1H-inden-1-yl]dimethylsilane (12.8 g, 16.34 mmol) in 100 ml of di-n-butyl ether at room temperature. This mixture was stirred for 4.5 h at room temperature, then the resulting red turbid solution was cooled to 0 °C in an ice- bath, then ZrCl4(3.81 g, 16.35 mmol) was added. The reaction mixture was stirred for 24 h at room temperature to give a dark red suspension. This suspension was evaporated to dryness, and the residue was extracted with 150 ml of warm toluene, and the precipitate was filtered off (G4). On the evidence of NMR spectroscopy, the resulting filtrate included only anti-dimethylsilanediyl[2-isopropyl-4,8-bis(3,5-dimethylphenyl)-1,5,6,7-tetrahydro-s- indacen-1-yl][2-methyl-4-(3,5-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl]zirconium dichloride contaminated with some polymeric by-products. This extract was evaporated to ca.30 ml, and 30 ml of hexane was added. The orange solid precipitated from this solution overnight at room temperature was filtered off (G4), washed with 10 ml of a mixture n- hexane-toluene (10:1, vol.) and then dried in vacuum. This procedure gave 3.8 g (24.7%) of anti-zirconocene dichloride. Anal. calc. for C56H64Cl2OSiZr.: C, 71.30; H, 6.84. Found: C, 71.45; H, 7.01.1H NMR (CDCl3): δ 7.73-6.81 (very br.s, 4H), 7.36 (s, 1H), 7.11 (s, 1H), 7.06 (s, 1H), 6.99 (s, 1H), 6.96 (s, 2H), 6.80 (s, 1H), 6.58 (s, 1H), 3.53-3.42 (m, 1H), 3.41 (s, 3H), 3.15-2.89 (m, 3H), 2.51-2.39 (m, 1H), 2.39 (s, 3H), 2.37 (s, 3H), 2.35 (s, 12H), 2.07-1.94 (m, 1H), 2.01 (s, 3H), 1.87-1.69 (m, 1H), 1.35 (s, 9H), 1.20 (d, J = 6.5 Hz, 3H), 1.15 (s, 3H), 0.99 Sensitivity: Internal (d, J = 6.4 Hz, 3H), -0.14 (s, 3H).13C NMR (CDCl3): δ 159.50, 148.44, 145.04, 143.76, 143.18, 141.52, 138.39, 138.10, 137.76 (br.s), 137.60, 136.92, 135.77, 135.48, 132.80, 132.72, 132.21, 130.51, 128.96, 128.81, 128.73, 128.64, 127.63, 127.52 (br.s), 126.82, 121.42, 120.40, 120.18, 116.93, 83.29, 80.61, 62.82, 35.58, 33.93, 32.31, 30.21, 30.16, 29.88, 26.10, 21.50, 21.44, 21.30, 20.33, 19.04, 4.84, 2.07. Catalyst synthesis, used chemicals MAO Axion CA133030 wt% solution in toluene was purchased from Chemtura / Lanxess and used as received and stored at –20 °C for not longer than 6 months. All the chemicals and chemical reactions were handled under an inert gas atmosphere using Schlenk and glovebox techniques, with oven-dried glassware, syringes, needles or cannulas. All catalysts have been prepared using silica Sunspera AGC DM-L-303, calcined at 600 °C. Catalyst preparations The catalysts were prepared by following a two-step preparation method. First step is the preparation of SiO2 / MAO (activated carrier), followed by a second step where a toluene solution of the metallocene complex is impregnated on the dry support from the first step. Only in case the metallocene is not enough soluble in toluene (metallocene MC-CE2), a second aliquot of MAO is added to the metallocene / toluene slurry in order to promote the full dissolution of the metallocene. Preparation of SiO2 / MAO activated carrier A steel reactor equipped with a mechanical stirrer and a filter net was flushed with nitrogen. 10 kg of SiO2 carrier was first added from a feeding drum into the reactor, followed by careful pressurizing and depressurizing with nitrogen. Then, toluene (43.5 kg) was added. The SiO2 / toluene slurry was stirred for 25 min at 22 °C. Then, 18 kg of 30 wt% MAO in toluene (Axion CA 1330) was added slowly (140 min) through a 12 mm line on the top of the reactor keeping the temperature around 22 °C. After MAO addition, the reactor temperature was quickly increased to 90 °C and the mixture was stirred at this temperature for 120 min. Then the hot toluene was filtered out and the solid cake was washed twice with hot toluene while stirring (43.5 kg, 90 °C, 30 min, 40 rpm). Each time the hot toluene was filtered out. Finally the solid cake was dried with slow stirring (5 rpm) under vacuum for 9 h at 80 °C. Sensitivity: Internal Synthesis of SiO2 / MAO / MC-CE1 = Comparison catalyst 1 (CE1) In a nitrogen filled glovebox, dry toluene (2.1 mL) was added to 41.9 mg of metallocene MC-CE1 (43.1 mg, purity 97.1 %, impurity being n-hexane). The mixture was stirred for 30 minutes at room temperature.2.0 g of the silica / MAO carrier was placed in a glass vial. The solution of metallocene in toluene was added dropwise by means of a syringe to the SiO2 / MAO carrier over the course of 5 minutes with gentle mixing. The resulting mixture was shaken well and allowed to stay for 1 hour. The resulting solid was dried in vacuum for 1 hour at 60°C to yield the catalyst as red free flowing powder Synthesis of SiO2 / MAO / MC-CE2 catalyst = Comparison catalyst 2 (CE2) In a nitrogen filled glovebox, dry toluene (2.5 mL) and MAO (0.1 mL) were added to 26.4 mg of metallocene rac-dimethylsilanediyl[2-methyl-4-(4’-tert-butylphenyl)-1,5,6,7- tetrahydro-s-indacen-1-yl])(2-isopropyl-4-(4’-tert-butyl-phenyl)indenyl) zirconium dichloride. The mixture was stirred for 30 minutes at room temperature. Next, 2.0 g of SiO2 / MAO was placed in a septum bottle. The solution of metallocene in toluene was added dropwise by means of a syringe to the SiO2 / MAO carrier over the course of 5 minutes with gentle mixing. The resulting powder was allowed to rest for 1 hour, then it was transferred into a Schlenk flask and dried under vacuum for 1 hour at 60 °C to yield the catalyst as a light red free-flowing powder. Synthesis of SiO2 / MAO / MC-IE1 = Inventive catalyst 1 (IE1) In a nitrogen filled glovebox, dry toluene (2.5 mL) was added to 29.0 mg of metallocene anti-MC-IE1. The solution was stirred for 30 minutes at room temperature. Next, 2.000 g of SiO2 / MAO was placed in a septum bottle. The solution of metallocene in toluene was added dropwise by means of a syringe to the SiO2 / MAO carrier over the course of 5 minutes with gentle mixing. The resulting powder was allowed to rest for 1 hour, then it was transferred into a Schlenk flask and dried under vacuum for 1 hour at 60 °C to yield the catalyst as a light red free-flowing powder. Synthesis of SiO2 / MAO / MC-IE2 = Inventive catalyst 2 (IE2) In a nitrogen filled glovebox, dry toluene (2.5 mL) was added to 28.3 mg of metallocene anti-MC-IE2. The mixture was stirred for 30 minutes at room temperature. Next, 2.000 g of SiO2 / MAO was placed in a septum bottle. The solution of metallocene in toluene was added dropwise by means of a syringe to the SiO2 / MAO carrier over the course of 5 minutes with gentle mixing. The resulting powder was allowed to rest for 1 hour, then it was transferred into a Schlenk flask and dried under vacuum for 1 hour at 60 °C to yield the catalyst as a light red free-flowing powder. Sensitivity: Internal The metallocene content in each catalyst is calculated by mass balance. The values are listed in Table 2: Table 2: Catalysts tested and their metallocene content Catalyst MC Al MC in catalyst * wt% wt% CE1 MC-CE1 13.2 1.56 CE2 MC-CE2 13.2 1.28 IE1 MC-IE1 13.8 1.43 IE2 MC-IE2 13.1 1.40 * metallocene content in the dry catalyst calculated from mass balance Polymerization examples Monomers and gases Hydrogen (quality 6.0) was supplied by Air Liquide and used as received. Propylene, quality 2.3, and ethylene have been purified by passing through columns filled with PolyMax301 T-4427B (60°C; Cu / CuO), Molecular sieve MS13X-APG 1 / 16 and Selexsorb COS 1 / 8. Propylene polymerization procedure (bulk, 5-L reactor) A stainless-steel reactor equipped with a ribbon stirrer, with a total volume of 5.3 dm³ was filled with 800 g propylene. Triethylaluminium (0.3 ml of 0.62 molar solution in n-heptane) was added using a stream of 150 g propylene, then the chosen amount of H2 (see Tables) was added via mass flow controller in one minute. The reactor temperature was stabilized at 25 °C (HB-Therm) and the solution was stirred and 250 rpm for at least 20 min. Then the catalyst was injected as described in the following. The desired amount of solid catalyst was loaded into a 5 ml stainless steel vial and then flushed into the reactor with 150 g propane. Stirring speed was kept at 250 rpm and pre- polymerization was run for 10 minutes at 25 °C. Then the polymerization temperature was increased to the set value. The second aliquot of H2 was added at 30 °C in between 1 and 6 min. The reactor temperature was kept constant throughout the polymerization. The polymerization time was measured starting when the temperature was 2 °C below the set polymerization temperature. When the polymerization time of 60 min had lapsed, the Sensitivity: Internal reaction was stopped by cooling the reactor and simultaneously flashing the volatile components. After purging the reactor 3 times with N2 and one vacuum / N2 cycle, the reactor was opened, the polymer powder was taken out and dried overnight in a fume hood. 50 g of the polymer was additivated with 0.5 wt% Irganox B225 (dissolved in acetone) and then dried overnight in a fume hood and additionally one hour in a vacuum drying oven at 60 °C. Propylene homopolymerization procedure (bulk, 20 L BSR) A stainless-steel reactor equipped with a ribbon stirrer, with a total volume of 20.9 dm³ containing 0.2 bar-g propylene, was filled with 3.95 kg propylene. Triethylaluminium (0.8 ml of 0.62 molar solution in n-heptane) was added using a stream of 250 g propylene, then 0.5 NL of H2 was added via mass flow controller in one minute. The reactor temperature was stabilized at 25 °C (HB-Therm) and the solution was stirred and 250 rpm for at least 20 min. Then the catalyst was injected as described in the following. The desired amount of solid catalyst was loaded into a 5 ml stainless steel vial. This feeder system was mounted on a port on the lid of the autoclave. Then the catalyst was flushed into the reactor with 350 g propylene. Stirring speed was kept at 250 rpm and pre- polymerization was run for 10 minutes at 25 °C or 30 °C. The second aliquot of H2 was added over 1 min at the end of the prepolymerization step at 30 °C. Then the polymerization temperature was increased to 70 °C. The reactor temperature was kept constant throughout the polymerization. The polymerization time was measured starting when the temperature was 2 °C below the set polymerization temperature. When the set polymerization time had lapsed, the reaction was stopped by injecting 5 ml ethanol, cooling the reactor and simultaneously flashing the volatile components. After purging the reactor 3 times with N2 and one vacuum / N2 cycle, the reactor was opened, the polymer powder is taken out and dried overnight in a fume hood.100 g of the polymer was additivated with 0.5 wt% Irganox B225 (dissolved in acetone) and then dried overnight in a fume hood and additionally one hour in a vacuum drying oven at 60 °C. Propylene / ethylene copolymerization procedure (bulk, 20 L BSR) These experiments have been performed identical to the homopolymerization experiment, with the exception that 109 g of ethylene has been fed via mass flow controller at constant rate over 1 minute at 30 °C at the end of the prepolymerization step, and the bulk step was performed at 70 °C. 2-step heterophasic copolymer production (hPP in bulk + EPR in gas phase, 20 L BSR) Step 1: Sensitivity: Internal A stainless-steel reactor equipped with a ribbon stirrer, with a total volume of 20.9 dm³ containing 0.2 bar-g propylene, was filled with 3.95 kg propylene. Triethylaluminium (0.8 ml of 0.62 molar solution in n-heptane) was added using a stream of 250 g propylene, then 0.5 NL of H2 was added via mass flow controller in one minute. The reactor temperature was stabilized at 25 °C (HB-Therm) and the solution is stirred and 250 rpm for at least 20 min. Then the catalyst was injected as described in the following. The desired amount of solid catalyst was loaded into a 5 ml stainless steel vial. This feeder system was mounted on a port on the lid of the autoclave. Then the catalyst was flushed into the reactor with 350 g propylene. Stirring speed was kept at 250 rpm and pre- polymerization was run for 10 minutes at 25 °C or 30 °C. Then the polymerization temperature was increased to 75 °C. The second aliquot of H2 was added over 1 min starting when the temperature of the liquid reaches 60 °C. The reactor temperature was kept constant throughout the polymerization. The polymerization time was measured starting when the temperature was 2 °C below the set polymerization temperature. When the set polymerization time had lapsed, the reaction was stopped by injecting 5 ml ethanol, cooling the reactor and simultaneously flashing the volatile components. After purging the reactor 3 times with N2 and one vacuum / N2 cycle, the reactor was opened, the polymer powder was taken out and dried overnight in a fume hood. 100 g of the polymer were additivated with 0.5 wt% Irganox B225 (dissolved in acetone) and then dried overnight in a fume hood and additionally one hour in a vacuum drying oven at 60 °C. Step 2: After the bulk homopolymerization step was completed, the stirrer speed was reduced to 50 rpm and the pressure was reduced to 0.4 bar-g by venting the monomers. The stirrer speed was set to 180 rpm and the reactor temperature was set to 70 °C. Then the reactor pressure was increased to 20 bar-g by feeding a defined C3 / C2 gas mixture (see tables). The C3 / C2 ratio is defined by where C2 / C3 is the weight ratio of the two monomers and R is their relative reactivity ratio, determined experimentally. In the present experiments, the value of R was set at 0.40The temperature was held constant by thermostat and the pressure was kept constant by feeding via mass flow controller a C3 / C2 gas mixture of composition corresponding to the target polymer composition and by thermostat, until the set time for this step had expired. Sensitivity: Internal Then the reactor was cooled down (to about 30 °C) and the volatile components flashed out. After purging the reactor 3 times with N2 and one vacuum / N2 cycle, the product was taken out and dried overnight in a fume hood.100 g of the polymer was additivated with 0.5 wt% Irganox B225 (solution in acetone) and dried overnight in a hood followed by 2 hours in a vacuum drying oven at 60°C. Propylene polymerization (liquid propylene) results (5 L reactor) We have compared the performance of four different metallocenes: MC-CE1, MC-CE2, MC-IE1, MC-IE2. The results are listed in Table 3. Table 3: Homopolymerization results in liquid propylene (MC=metallocene) Prepoly Trans. BULK Results MC Cat. MC T time H2 H2 T time Produc MC MFR2 Tm tivity producti powd vity er mg mg °C min NL NL °C min kg / kg / g / °C gcat gMC 10min MC- 22.0 0.34 25 10 0.125 0.625 75 60 15.8 1011 0.9 151 CE1 MC- 14.2 0.22 25 10 0.125 0.625 75 60 11.3 721 1.4 151 CE1 MC- 10.3 0.16 25 10 0.125 1.375 75 60 11.5 740 202 151 CE1 MC- 9.8 0.15 25 10 0.125 0.875 75 60 13.5 866 14.6 150 CE1 MC- 18.4 0.29 25 10 0.125 0.125 75 60 6.4 408 0.06 152 CE1 MC- 23.0 0.29 25 10 0.125 0.630 75 60 9.3 724 61.5 157 CE2 MC- 29.0 0.37 25 10 0.125 0.125 75 60 4.1 318 1.6 157 CE2 MC- 21.0 0.27 25 10 0.125 1.375 75 60 7.8 606 3383 158 CE2 MC- 23.0 0.29 25 10 0.125 0.875 75 60 8.8 690 1210 155 CE2 Sensitivity: Internal MC- 15.1 0.21 25 10 0.125 0.625 75 60 6.6 471 34.5 155 IE2 MC- 11.7 0.16 25 10 0.125 1.375 75 60 8.1 582 2302 153 IE2 MC- 24.4 0.34 25 10 0.125 0.125 75 60 5.6 404 1.2 156 IE2 MC- 13.0 0.19 25 10 0.130 0.630 75 60 8.5 597 90.8 160 IE1 MC- 9.9 0.14 25 10 0.125 0.875 75 60 6.1 429 464 159 IE1 MC- 22.6 0.32 25 10 0.125 0.875 75 60 7.1 497 453 159 IE1 MC- 32.3 0.46 25 10 0.125 0.125 75 60 3.0 213 6.8 160 IE1 Cat. = Catalyst Amount MC = MC Amount In terms of polymerization performance, both new complexes are more isoselective in propylene polymerization upon MAO activation compared to MC-CE1, producing under standard bulk conditions hPP having higher Tm compared to MC-CE1. It is further noted that 2-isopropyl substitution of the methoxyindenyl ligand (MC-IE1) gives a higher isoselectivity compared to 2-isopropyl on the indacenyl ligand (MC-IE2) as can be seen from Figure 1 illustrating the melting point of the hPP as a function of MFR2. Propylene / ethylene copolymerization results (liquid propylene, 20 L reactor) The experimental settings are listed in Table 4 and the results are listed in Tables 5 and 6 respectively. Sensitivity: Internal Table 6 Solution13C NMR Catalyst C2 C2 R E-2,1 2,1e 3,1 wt% mol% mol% mol% mol% IE1 0 0 - 0,0 0,2 0,2 IE1 3,0 4,5 1,5 0,0 0,2 0,0 CE1 1,4 2,2 0,7 0,2 0,6 0,0 CE2 1,3 2,0 0,7 0,0 0,1 0,0 Sensitivity: Internal The copolymerisation experiments in liquid monomer, performed under conditions to provide copolymers of similar MFR2, show that the inventive catalyst IE1 is strongly activated by ethylene and has a higher ethylene reactivity than both CE1 and CE2, and produce copolymers of narrower MwD, a property that makes them suitable especially for fibre production. Results of 2-step heterophasic copolymer production (propylene homopolymerization in liquid propylene followed by gas phase ethylene / propylene copolymerization in gas phase propylene, 20 L reactor) The experimental settings and results are listed in Table 7 and Table 8, respectively. Sensitivity: Internal Table 7 Prepolymerization Bu Transition from step Transition lk step bulk to gas Gas phase phase g inde ) ) efCF C ) ) 2 F t C C n H M M uer fer(n(F F nerM M t o s lymuteomerutaioioarerut(2(2 eitsits uare P P t atarita s ep.2 2ute s H H cly arp mitn a n s ras ep mitG Gatmerep metrnt ern P m n ein did aetm Ti iT efe c e d dfte e 2 3 gf fi C C n 2 3 trC C atS mg °C min NL NL °C °C min g g barg °C min g g CE2 89,0 25 10 0,50 2,52 607540 250,3 304,8 20 70120158473 IE1 94,0 30 10 0,50 2,50 607540239,45 286,5 20 7012090276 Table 8 Analysis whole polymer Analysis soluble fraction yitldsn re tsiee d ) lyydx n R r atelkwo uebpFtSs TmMyMw / M w N(R a m yr2rclo e R C M 2 d F C P w M o P name g g / ml g / 10min wt% °C g / mol wt% CE2 1140 0,38 63,0 54,3 156,6 338000 3,7 23,4 0,37 IE1 990 0,4 142,0 31,9 157,8 536000 2,4 26,9 0,44 Sensitivity: Internal One can see that the catalyst of the invention (IE1) produces an ethylene / propylene copolymer of narrower molecular weight distribution and higher molecular weight than the comparison catalyst CE2. In addition, IE1 has higher ethylene reactivity compared to CE2, as shown by the higher values of the reactivity ratio R. Sensitivity: Internal

Claims

CLAIMS 1. A metallocene complex of formula (I)wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; n are each independently, same or different from each other, an integer from 1 to 5; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, -OR31, SR31, or N(R31)2,with R31being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R5and R6are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7carbocycle; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl.

2. A metallocene complex of formula (I) as claimed in claim 1 having formula (I-a) Sensitivity: Internalwherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, -OR31, SR31, or N(R31)2, with R31being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R5and R6are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7carbocycle; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl.

3. A metallocene complex of formula (I) as claimed in claim 1 or 2 having formula (I-b) Sensitivity: Internalwherein Mt is Zr or Hf: X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; n are each independently an integer from 1 to 5; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R5and R6are each independently, same or different from each other, H or C1-C10- hydrocarbyl, or may form together with the C atoms they are attached to a C5-C7 carbocycle.

4. A metallocene complex of formula (I) as claimed in any one of claims 1 to 3 having formula (I-c) Sensitivity: Internal(I-c) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; n are each independently an integer from 1 to 5; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl.

5. A metallocene complex of formula (I) as claimed in any one of claims 1 to 4 having formula (I-d) Sensitivity: Internal(I-d) wherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2and R2’ are each independently a C1-C10-hydrocarbyl, provided that at least one of R2and R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H.

6. A metallocene complex of formula (I) as claimed in any one of claims 1 to 4 having formula (I-e)Sensitivity: Internalwherein Mt is Zr or Hf; X is a sigma ligand; R1are each independently, same or different from each other, C1-C20-hydrocarbyl, optionally containing up to two heteroatoms of Group 14-16 of the Periodic Table, or form together with the Si atom they are attached to a C4-C8-ring; R2’ is an alpha-branched C3-C10-hydrocarbyl; R3and R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1-C10-hydrocarbyl, whereby at least one R3per phenyl group and at least one R4is not H.

7. A metallocene complex as claimed in any one of claims 1 to 6, wherein one or two R3per phenyl group are not H and on both phenyl groups the R3are the same, and two R4on the phenyl group are not H and these two R4are the same.

8. A polymerization catalyst, comprising, preferably consisting of (i) a metallocene complex of formula (I) as claimed in any one of claim 1 to 7; (ii) a cocatalyst comprising a group 13 element; and (iii) optionally a support.

9. The polymerization catalyst according to claim 8, wherein cocatalyst (ii) is an aluminoxane cocatalyst, preferably in the absence of any further cocatalysts.

10. The catalyst system as claimed in claim 8 or 9, supported on silica.

11. A process for the polymerization of propylene, comprising polymerizing propylene and optionally at least one of comonomer selected from ethylene or C4-C10-alpha olefin comonomers in the presence of the polymerization catalyst claimed in any one of claim 8 to 10.

12. A process for the preparation of a heterophasic polypropylene copolymer comprising (I) polymerizing propylene in bulk in the presence of a polymerization catalyst as claimed in claim 8 to 10 to form a polypropylene homopolymer matrix; Sensitivity: Internal(II) in the presence of said matrix and said polymerization catalyst and in the gas phase, polymerizing propylene and ethylene to form a heterophasic polypropylene copolymer comprising a homopolymer matrix and an ethylene propylene rubber.

13. A process for the preparation of a heterophasic polypropylene copolymer comprising (I) polymerizing propylene in bulk in the presence of polymerization catalyst as claimed in claim 8 to 10 to form a polypropylene homopolymer; (II) in the presence of said homopolymer and said polymerization catalyst and in the gas phase, polymerizing propylene to form a polypropylene homopolymer matrix; (III) in the presence said matrix and said polymerization catalyst and in the gas phase, polymerizing propylene and ethylene to form a heterophasic polypropylene copolymer comprising a homopolymer matrix and an ethylene propylene rubber (EPR).

14. An indene of formula (II)wherein the dotted lines represent a double bond present in between carbons 1 and 2 or 2 and 3 of the indenyl ring; R2’ is an alpha-branched C3-C10-hydrocarbyl; R4are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1- C10-hydrocarbyl, whereby at least one R4is not H; R51’ is C1-C10-hydrocarbyl; and R6’ is C(R61)3, with R61being linear or branched C1-C6-alkyl.

15. An indene of formula (III) Sensitivity: Internalwherein the dotted lines represent a double bond present in between carbons 1 and 2 or 2 and 3 of the indenyl ring; R2is an alpha-branched C3-C10-hydrocarbyl; R3are each independently, same or different from each other, H, linear or branched C1-C6-alkyl, C7-C20-arylalkyl, C7-C20-alkylaryl, C6-C20-aryl, or -OR31, with R31being C1- C10-hydrocarbyl, whereby at least one R3per phenyl group is not H. Sensitivity: Internal

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