Process for the preparation of organotin compounds

Abstract

The invention provides a convenient method for preparing certain organotin compounds having alkyl and alkylamino substituents. The method provides organotin precursor compounds, such as tris(dimethylamido)isopropyltin, in highly pure form. Thus, the products of the method are particularly suitable for depositing high purity tin oxide films in, for example, extreme ultraviolet (EUV) photolithography techniques used in microelectronic device manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of organotin chemistry. Specifically, this invention relates to a convenient method for preparing certain organotin compounds, such as tris(dimethylamino)isopropyltin with extremely high selectivity. Background Technology

[0002] Certain organotin compounds have been shown to be suitable for depositing highly pure tin(II) oxide in applications such as extreme ultraviolet (EUV) lithography used in the manufacture of certain microelectronic devices.

[0003] Organotin compounds having combinations of alkylamino and alkyl groups have attracted considerable attention as suitable liquid precursors for depositing tin-containing films onto substrates of microelectronic devices. Therefore, there is a need for improved methods for manufacturing such organotin compounds in highly pure form for depositing highly pure tin oxide films. Summary of the Invention

[0004] A convenient method is provided for preparing certain organotin compounds having alkyl and alkylamino substituents. This method is particularly useful in cases where polyalkyl byproducts cannot be effectively removed by distillation, such as dialkyltin and dialkylamino compounds relative to monoalkyl species because their boiling points are very close. The method provides organotin precursor compounds, such as tris(dimethylamino)isopropyltin (CAS No. 1913978-89-8), in highly pure form. Therefore, the products of this method are particularly suitable as precursors for depositing tin oxide films in extreme ultraviolet (EUV) lithography techniques, for example, in the fabrication of microelectronic devices. Attached Figure Description

[0005] Figure 1 Crystal structure description of compound of formula (Aa):

[0006]

[0007] Figure 2 Crystal structure description of compound of formula (Ad):

[0008]

[0009] That is, the Lewis base adduct of ethyltin trichloride dimethylamine. Detailed Implementation

[0010] As used in this specification and the appended claims, unless the context clearly specifies otherwise, the singular forms “a / an” and “the” include a plurality of indicators. As used in this specification and the appended claims, unless the context clearly specifies otherwise, the term “or” is generally used to mean “and / or”.

[0011] The term "approximately" generally refers to a range of values ​​that are considered equivalent to the stated value (e.g., having the same function or result). In many cases, the term "approximately" may include values ​​rounded to the nearest significant number.

[0012] The range of values ​​expressed using endpoints includes all values ​​contained within the range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0013] In a first aspect, the present invention provides a method for preparing a composition comprising a compound of formula (I):

[0014]

[0015] Each R is independently selected from C1-C5 alkyl groups, and R 1 Selected from C1-C5 alkyl groups, the method includes combining the following:

[0016] a) Equation R 1 The SnX3 compound, wherein X is selected from Cl, I, and Br.

[0017] b) Li(R)₂N compound, and

[0018] c) R2NH compound,

[0019] Among them, the compound of formula R2NH is compared with that of formula R 1 The SnX3 compound is present in molar excess. For example, a composition including a compound of formula (I) can be prepared by a method comprising: making formula R 1 The SnX3 compound is contacted with a Li(R)2N compound and a R2NH compound. One or more of the steps in this method may preferably be carried out under conditions that minimize the exposure of the material and / or product to light.

[0020] C1-C5 alkyl groups include straight-chain or branched-chain alkyl groups. Examples include methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, and secondary pentyl. The R and R' in this document... 1 Each of these groups is independently selected from such groups, and thus a compound of formula (I) can be defined, wherein one or more groups are different from the other groups. Preferably, R and R 1 It is independently selected from C1-C3 alkyl groups.

[0021] As explained above, compounds of formula R2NH (i.e., dialkylamines) are relative to those of formula R 1 The SnX3 compound is present in a molar excess; in one embodiment, this molar excess is relative to formula R. 1The amount of the SnX3 compound is at least about 0.15 molar equivalents. In another embodiment, the compound of formula R2NH is a dimethylamine, and R 1 It is isopropyl. In another embodiment, R... 1 X is isopropyl and chlorine. In another embodiment, the compound of formula Li(R)₂N is lithium dimethylamino, the compound of formula R₂NH is dimethylamine, and R… 1 The SnX3 compound is isopropyltin trichloride.

[0022] In this regard, examples of compounds of formula (I) include: tris(dimethylamino)isopropyltin; tris(diethylamino)isopropyltin; tris(dipropylamino)isopropyltin; tris(methylethylamino)isopropyltin; tris(diisopropylamino)isopropyltin; tris(di-tert-butylamino)isopropyltin; tris(di-n-butylamino)isopropyltin; tris(di-sec-butylamino)isopropyltin; tris(di-neopentylamino)isopropyltin; tris(dimethylamino)methyltin; tris(di-... Tris(di-n-propylamino)methyltin; Tris(methylethylamino)methyltin; Tris(diisopropylamino)methyltin; Tris(di-tert-butylamino)methyltin; Tris(di-n-butylamino)methyltin; Tris(di-sec-butylamino)methyltin; Tris(di-neopentylamino)methyltin; Tris(dimethylamino)ethyltin; Tris(diethylamino)ethyltin; Tris(di-n-propylamino)ethyltin; Tris(methylethylamino)ethyltin; Tris(diisopropylamino)methyltin (Amino)ethyltin; Tris(di-tert-butylamino)ethyltin; Tris(di-n-butylamino)ethyltin; Tris(di-sec-butylamino)ethyltin; Tris(di-neopentylamino)ethyltin; Tris(dimethylamino)n-propyltin; Tris(diethylamino)n-propyltin; Tris(di-n-propylamino)n-propyltin; Tris(methylethylamino)n-propyltin; Tris(diisopropylamino)n-propyltin; Tris(di-tert-butylamino)n-propyltin; Tris(di-n-butylamino)n-propyltin; Tris(di-sec-butylamino)-n-propyltin; Tris(di-neopentylamino)-n-propyltin; Tris(dimethylamino)-n-butyltin; Tris(diethylamino)-n-butyltin; Tris(dipropylamino)-n-butyltin; Tris(methylethylamino)-n-butyltin; Tris(diisopropylamino)-n-butyltin; Tris(di-tert-butylamino)-n-butyltin; Tris(di-n-butylamino)-n-butyltin; Tris(di-sec-butylamino)-n-butyltin; Tris(di-neopentylamino)-n-butyltin; and the like.

[0023] Formula R 1 SnX3 compounds can be prepared, for example, by a redistribution reaction between iPrSnPh3 (iPr = isopropyl and Ph = phenyl) and SnCl4. In some embodiments, the stoichiometric ratio can be 1:1 or 3:1 (R... 1The variation is between SnPh3:SnX4). In one embodiment, formula R is prepared before use. 1 The SnX3 compound is distilled once or multiple times. In practice of the invention, formula R... 1 The SnX3 compound is isopropyltin trichloride, and distillation prior to use provides a reactant with at least approximately 99.9% purity.

[0024] In one embodiment, equation R 1 The SnX3 compound comprises isopropyltin trichloride, isopropyltin tribromide, and isopropyltin triiodide. In one embodiment, formula R 1 The SnX3 compound is isopropyltin trichloride. Therefore, the following references to isopropyltin trichloride also apply to isopropyltin tribromide and isopropyltin triiodide, as well as other compounds of formula R as defined herein. 1 SnX3 compounds. Depending on the solvent used, formula R 1 SnX3 compounds can be added in the form of solutions or slurries. For example, they can form slurries in hydrocarbon solvents such as hexane; and solutions in ethers such as tetrahydrofuran.

[0025] In the above method, the compound of formula R2NH is relative to formula R 1 The SnX3 compound is present in a molar excess. In some embodiments, this molar excess will be at least about 0.15 or at least about 4. In one embodiment, relative to formula R... 1 The SnX3 compound, this molar excess can be about 2 to about 10, for example about 2 to about 8 or about 2 to about 4.

[0026] In the above method, a nonpolar, aprotic solvent, such as hexane, can be used. The method can be carried out at a decreasing temperature from about -78°C to about 10°C. At ambient temperature (i.e., from about 17°C to about 27°C), the reaction time can be any time from 1 to 60 hours. The reaction mixture can be filtered and subsequently vacuum distilled to remove the solvent. Non-reactive filter aids, such as diatomaceous earth (i.e., celite), can be used, but higher purity products can be produced without such filter aids due to, for example, the presence of metal species in the filter aid. After filtering out any residual solids, the crude product can be purified by short-path distillation.

[0027] In one embodiment, isopropyltin trichloride is distilled before use to remove impurities. For example, isopropyltin trichloride can be distilled to provide a reactant with at least about 99.9% purity.

[0028] Lithium dimethylamino is commercially available or can be newly prepared from dimethylamine and alkyllithium reagents.

[0029] As noted above, the method of the present invention makes it possible to synthesize compound (I) with extremely high purity, containing trace amounts of dialkyl impurities. Therefore, in another aspect, the present invention provides a composition comprising compound (I):

[0030]

[0031] Each R is independently selected from C1-C5 alkyl groups, and R 1 Selected from C1-C5 alkyl groups, wherein the composition comprises less than about 0.5 mol% of a compound of formula (II):

[0032]

[0033] As a specific embodiment, R 1 Selected from C1-C3 alkyl groups, such as methyl, ethyl, n-propyl, and isopropyl (iPr).

[0034] In one embodiment, the composition comprising the compound of formula (I) comprises less than about 0.1% of the compound of formula (II). In one embodiment, the compound of formula (II) is bis(dimethylamino)diisopropyltin, and the compound of formula (I) is tris(dimethylamino)isopropyltin.

[0035] In another embodiment, the composition comprising the compound of formula (I) includes less than about 0.05% of the compound of formula (II). In one embodiment, the compound of formula (II) is bis(dimethylamino)diisopropyltin, and the compound of formula (I) is tris(dimethylamino)isopropyltin.

[0036] In another embodiment, the composition comprising the compound of formula (I) includes less than about 0.04% of the compound of formula (II). In one embodiment, the compound of formula (II) is bis(dimethylamino)diisopropyltin, and the compound of formula (I) is tris(dimethylamino)isopropyltin.

[0037] In another embodiment, the composition comprising the compound of formula (I) includes less than about 0.03% of the compound of formula (II). In one embodiment, the compound of formula (II) is bis(dimethylamino)diisopropyltin, and the compound of formula (I) is tris(dimethylamino)isopropyltin.

[0038] In another embodiment, the composition comprising the compound of formula (I) includes less than about 0.02% of the compound of formula (II). In one embodiment, the compound of formula (II) is bis(dimethylamino)diisopropyltin, and the compound of formula (I) is tris(dimethylamino)isopropyltin.

[0039] As will be seen in Example L below, when the compound of formula (I) is tris(dimethylamino)isopropyltin (i.e., where each R is a methyl group, and R...), 1 When it is isopropyl), it is possible to reach a purity level that allows for the removal of undesirable bis(dimethylamino)diisopropyltin impurities (i.e., formula (II), where each R is a methyl group and each R is a methyl group). 1 The presence of isopropyl (which cannot be detected by conventional methods) 119 Sn NMR analysis, for example, using JEOL ECZ 400 for detection, where the residence time in NMR is from about 1 h to about 10 h for quantitative data acquisition.

[0040] In the above method, the verdict and formula R 1 Compared to the SnX3 compound, a molar excess of the R2NH compound yields an in-situ intermediate Lewis base adduct of formula (A):

[0041]

[0042] Each R is independently selected from C1-C5 alkyl groups, R 1 Selected from C1-C5 alkyl groups, and X selected from Cl, I, or Br. For example, each R and R 1 The alkyl group can be selected from C1-C5 alkyl groups, such as methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, and sec-butyl. Therefore, one embodiment of the present invention is a method for preparing a compound of formula (I) from a compound of formula (A), wherein the compound of formula (A) is prepared by reacting a compound of formula R2NH with a compound of formula R... 1 The SnX3 compound reacts with a Li(R)2N compound to form the compound. In this embodiment, the R2NH compound is more abundant than the R... 1 SnX3 compounds.

[0043] In a specific instance of the above method, a molar excess of dimethylamine, compared to about 0.15 to about 10 isopropyltin trichloride in one embodiment, yields an in-situ intermediate Lewis base adduct having formula (Aa):

[0044]

[0045] In a similar manner, a molar excess of dimethylamine compared to ethyltin trichloride yields an in-situ Lewis base adduct of formula (Ad):

[0046]

[0047] For example, when an excess of dimethylamine is used in the reaction, a significant reduction in the formation of the undesirable dialkyl byproduct bis(dimethylamino)diisopropyltin has been observed. In this regard, the reproduction of Example 1 of WO2017 / 066319, as shown in Comparative Example 1 below, produces the desired tris(dimethylamino)isopropyltin and approximately 1.6 molar percentages (as shown by...) 119 The product mixture of undesirable bis(dimethylamino)diisopropyltin (as determined by Sn NMR integration). While it is undesirable to be bound by any particular mechanism, it is believed that excess dimethylamine forms a corresponding Lewis base adduct in situ, which advantageously improves the selectivity of the reaction with lithium dimethylamino and thus greatly enhances the purity of the desired compound of formula (I), such as tri(dimethylamino)isopropyltin. Furthermore, this effect is enhanced when freshly prepared or purified reactants are carefully used.

[0048] As further support, the Lewis base adduct (Aa) was prepared, isolated, and crystallized:

[0049]

[0050] The reaction of the adduct (Aa) with lithium dimethylamino yields tris(dimethylamino)isopropyltin in high yields and with excellent selectivity for monoisopropyl species at contamination levels as low as approximately 0.03%, 0.02%, 0.01%, or 0.001% (with diisopropyl species), and may not be readily achievable through conventional methods. 119 Sn NMR analysis, for example, using a JEOL ECZ 400 for detection, wherein the residence time in the NMR is about 1 h to about 10 h for quantitative data acquisition. Therefore, in another aspect, the present invention provides a compound of formula (A), which is suitable as an intermediate in the synthesis of formula (I).

[0051] In one embodiment, the compound of formula (A) is added as a slurry in a hydrocarbon solvent to a slurry of lithium dimethylamino in a hydrocarbon solvent.

[0052] In one embodiment, lithium dimethylamino is newly prepared from dimethylamine and alkyllithium.

[0053] In a similar manner, tin compounds of formula (Ab) substituted with iodine and tin compounds of formula (Ac) substituted with bromine can be prepared and separated:

[0054] and

[0055]

[0056] Therefore, compounds of formulas (Aa), (Ab) and (Ac) are also suitable as intermediates in the synthesis of high-purity tris(dimethylamino)isopropyltin and form another aspect of the present invention.

[0057] Therefore, in another aspect, the present invention provides a method for preparing a composition comprising a compound of formula (Ia):

[0058]

[0059] The method includes using a compound of formula (Aa):

[0060]

[0061] Contact with lithium dimethylamino. Furthermore, the present invention provides a method for preparing a composition comprising a compound of formula (Id):

[0062]

[0063] The method includes using a compound of formula (Ad):

[0064]

[0065] Contact with lithium dimethylamino.

[0066] In the method of the present invention, depending on the solvent or medium used, lithium dimethylamino will be a solution or a slurry; for example, in the case of tetrahydrofuran, lithium dimethylamino will generally be a solution, and in hydrocarbons, lithium dimethylamino will generally be in slurry form. In one embodiment, the compound of formula (Aa) is in slurry form in a hydrocarbon solvent such as hexane. In another embodiment, the compound of formula (Aa) is dissolved in an ether solvent such as tetrahydrofuran.

[0067] Generally, lithium dimethylamino is present in a molar excess, i.e., at least about 3 molar equivalents of lithium dimethylamino relative to 1 molar equivalent of compound (Aa), in order to react completely with the three chlorine atoms on compound (Aa). In one embodiment, about 3 to 3.2 molar equivalents of lithium dimethylamino are used relative to compound (A). When preparing lithium dimethylamino, the presence of a molar excess of dimethylamine, for example at least about 1.05 molar equivalents of dimethylamine (relative to an alkyl lithium starting material, such as n-butyllithium), is advantageous.

[0068] In one embodiment, the composition includes less than about 0.5% molar percentage of an impurity, wherein the impurity is composed of bis(dimethylamino)diisopropyltin.

[0069] The precursors used to prepare (Ab) and (Ac) compounds can be prepared from the corresponding isopropyltin trihalomethane compounds according to the following procedure:

[0070]

[0071] Where X is bromine or iodine. The excess iodine or bromine can be replaced by monoiodide chloride or monoiodide bromide, as described, for example, in the following literature: (i) halogen cleavage of Mesubi, MA; Afolabi, MO; Falase, KO cyanomethyltriphenyltinane. of Cyanomethyltriphenylstannane). Inorganic and Nuclear Chemistry Letters (Inorg. Nucl. Chem. Lett.) 1976, 12, 469-474, https: / / doi.org / 10.1016 / 0020-1650(76)80148-1; (ii) Bullard, RH; Robinson, WB. Methylphenylstannanes. Journal of the American Chemical Society (J. Am. Chem. Soc.) 1927, 49, 1368-1373, https: / / doi.org / 10.1021 / ja01404a030; (iii) Shekouhian, M. Hassan. Organotin Compounds - A Mechanistic Approach for Their Synthesis. Journal of Current Advances in Applied Sciences (J. Recent Adv. Appl. Sci., 1988, 3, 483-486; (iv) Bhattacharya, SN; Husain, Ishrat. Reactions of Tin-Naphthyl Bond with Halogens and Pseudohalogens. Indian J. Chem. Secret. Inorg. Phys. Theor. Anal., 1981, 20A, 1119-1121; and (v) Bhattacharya, SN; Raj, P.; Singh, Meenu.Studies on the synthesis and structure of some new unsymmetric and asymmetric organotin (IV) halides, pseudohalides, and carboxylates and their complex anions (Indian Journal of Chemistry - Inorganic Physics Theor. Anal., 1979, 18A, 231-235).

[0072] Therefore, similar to the corresponding isopropyltin trichloride, the following compound can be made...

[0073]

[0074] Wherein X is bromine or iodine; contact with 2.0, 4.0, or up to 6.0 molar equivalents of dimethylamine to ensure the formation of Lewis base adducts (e.g., compounds of formulas (Ab) and (Ac), followed by removal of the solvent under vacuum to obtain the compound in crystalline form. Therefore, in another embodiment, the present invention provides compounds of formulas (Aa), (Ab), and (Ac) in crystalline form. In one embodiment, the crystalline form of the compound of formula (Aa) is as follows: Figure 1 As shown in the image.

[0075] On the other hand, the present invention provides a method for preparing R 1 A method for SnX3 compounds, wherein X is chlorine or bromine and R... 1 Selected from C1-C5 alkyl groups, the method is achieved by making formula R 1 SnR 4 The three compounds were reacted with monoiodide chloride or bromide, respectively, where R 4 The compounds are selected from aryl, C2-C8 alkenyl, and C2-C8 ynyl groups, and thus provide corresponding isopropyltin trihalides and iodobenzene. In this regard, aryl groups comprise aromatic carbon rings optionally substituted with C1-C6 alkyl, halogen, nitro, cyano, C1-C6 alkoxy, C1-C6 alkylamino, and C1-C6 dialkylamino groups, such as phenyl and naphthyl groups. C2-C8 alkenyl and C2-C8 ynyl groups should be understood to represent two to eight carbon hydrocarbons having at least one double or triple bond, and the linkage point may be a linkage point with a carbon having a double or triple bond or with another carbon in the chain.

[0076] On the other hand, the present invention provides a method for preparing R 1A method for SnX3 compounds, wherein X is chlorine, bromine, or iodine and R... 1 Selected from C1-C5 alkyl groups, the method includes making formula R 1 SnR 2 Compound 3 is contacted with compound of formula SnX4, wherein R 2 Selected from aryl or C2-C8 alkenyl groups.

[0077] Example

[0078] Example 1 - Synthesis and isolation of bis(dimethylamine) Lewis base adduct of isopropyltin trichloride

[0079] A 100 mL round-bottom flask with a gas / vacuum inlet side arm connector was fitted with a 7 mm tubing connector. Isopropyltin trichloride (11.0 g, 41.02 mmol) was added to the flask, followed by 60 mL of anhydrous hexane. The flask was sealed and removed from the glove box. The flask was cooled in an ice bath and subjected to a 48-minute induction process via… 1 Dimethylamine (9.00 g, 199.6 mmol) was slowly bubbled into the solution using a 4" PFA tube. A white solid precipitate was observed upon completion of the addition. The mixture was heated to ambient temperature and stirred for 2 h; it was then filtered and dried under vacuum to obtain 12.88 g (86.9%) of the desired product as a white solid. Hexane was slowly evaporated from the filtrate to give colorless crystals of iPrSnCl3(HN(CH3)2)2.

[0080] 1 H NMR (400MHz, CDCl3, 298K): δ3.41(s,2H),2.79(s,12H),2.29(sept,1H),1.45(d,6H)ppm. 13 C{ 1 H}NMR (100MHz, CDCl3 289K): δ45.36, 39.60, 22.38ppm. 119 Sn{ 1 H} NMR (149MHz CDCl3, 298K): δ-405.8ppm.

[0081] Example 2 - Synthesis and isolation of the Lewis base adduct of isopropyltin triiodide dimethylamine

[0082] Isopropyltin triiodide (10.0 g, 18.43 mmol) can be added to a 100 mL round-bottom flask equipped with a 7 mm tubing connector and a gas / vacuum inlet side arm connector, followed by 60 mL of anhydrous hexane, sealed, and transferred out of the glove box. The flask can be cooled in an ice bath and can be transported via… 1Dimethylamine (2.50 g, 55.3 mmol) was slowly bubbled into the solution using a 4" PFA tube. A white solid precipitate was observed upon completion of the addition. The mixture was then heated to ambient temperature and stirred for 2 hours, filtered, and dried under vacuum to obtain the desired product.

[0083] Example 3 - Synthesis and isolation of the bis(dimethylamine) Lewis base adduct of isopropyltin tribromide

[0084] Isopropyltin tribromide (10.0 g, 24.90 mmol) can be added to a 100 mL round-bottom flask equipped with a 7 mm tubing connector and a gas / vacuum inlet side arm connector, followed by 60 mL of anhydrous hexane, sealed, and transferred out of the glove box. The flask can be cooled in an ice bath and can be transported via… 1 Dimethylamine (3.37 g, 74.7 mmol) was slowly bubbled into the solution using a 4" PFA tube. A white solid precipitate was observed upon completion of the addition. The mixture was then heated to ambient temperature and stirred for 2 hours, filtered, and dried under vacuum to obtain the desired product.

[0085] Example 4

[0086] In an inert atmosphere glove box, a 100 mL round-bottom flask with a heat-shrink tubing was fitted with a PTFE boiling chip, 50.0 g (127.1 mmol) isopropyltriphenyltin, and 99.3 g (381.2 mmol) tin chloride (IV). Note the significant exothermic reaction, and once the mixture had cooled to ambient temperature, the flask was connected to a distillation assembly encapsulated in 0.16 square inches of stainless steel. The apparatus consisted of a 12" silver-plated vacuum jacketed column, a variable reflux distillation head with a pressure equalization arm, and a 100 mL round-bottom receiving flask with a gas / vacuum inlet side arm. The reaction mixture was heated to 120 °C for 3 hours and then distilled at 100 mTorr, with head temperatures ranging from 29 to 45 °C and an average head temperature of 36 °C. The collection consisted of 8.24 g (via...) 119 The first eluent consisted of 99.9% pure Sn NMR and 24.6 g (by... 119 The second elution fraction (99.6% pure Sn NMR) was used to obtain a combined yield of 32.8 g (96%, 99.7% pure).

[0087] 1 H NMR (400MHz, CDCl3, 298K): δ1.61(sept,1H)1.38(d,6H)ppm. 13 C{ 1 H} NMR (100MHz, CDCl3 289K): δ40.91, 19.68ppm. 119 Sn{1 ¹H NMR (149MHz pure, 298K): δ-12.3ppm.

[0088] Example A to I - Synthesis of Tris(dimethylamino)isopropyltin

[0089] The title compound was synthesized according to the following procedure, with Tables 1A and 1B below outlining several experiments involving variations of certain parameters.

[0090] Programs for Examples A and B

[0091] Lithium dimethylamino (4.26 g, 83.5 mmol) and 36 mL of hexane were added to a 100 mL round-bottom flask with a gas / vacuum inlet side arm. Isopropyltin trichloride (7.00 g, 26.1 mmol) and any additives listed in Table 1A below were added to a 5 mL syringe with a valve. The lithium dimethylamino slurry was cooled to -65 °C and isopropyltin trichloride was added dropwise over 10 minutes. Only minimal exothermic reaction was observed, and the mixture was heated to ambient temperature. The reaction mixture was stirred at ambient temperature for 36 hours and then filtered through a diatomaceous earth bed and all volatiles were stripped under vacuum. The crude product was purified by short-path distillation under reduced pressure to give iPrSn(NMe2)3 in 55% yield, as shown by... 119 The SnNMR analysis showed that it contained 0.8% iPr2Sn(NMe2)2 impurity.

[0092] 1 ¹H NMR (400MHz, d6-benzene, 298K): δ 2.83 (s, 18H), 1.63 (sept, 1H), 1.27 (d, 6H) ppm. 13 C{ 1 ¹H NMR (100MHz, d6-benzene, 289K): δ 43.6, 21.2, 14.9ppm. 119 Sn{ 1 ¹H NMR (149MHz pure, 298K): δ-64.3ppm.

[0093] Programs for examples C, D, F, and H

[0094] Butyllithium (23.7 mL, 59.4 mmol) was added to a 250 mL three-necked round-bottom flask containing a PTFE-coated stirring egg, diluted with 25 mL of anhydrous hexane, and fitted with a 7 mm tubing connector, a 7 mm valved side arm tubing connector, and a gas / vacuum inlet connector. The flask was cooled to 2°C in an ice bath. A condenser was fitted between the flask and the gas / vacuum inlet connector, and dimethylamine (6.20 g, 138 mmol, 6.94 eq) was slowly bubbled through a 1 / 4" PFA tubing. The reaction mixture was cooled to approximately -10°C, and a solution of isopropyltin trichloride (5.31 g, 19.8 mmol) diluted to 29 mL with hexane was slowly added via a syringe pump over 47 minutes (0.61 mL / min). The reaction mixture was then warmed to ambient temperature over 20 minutes and stirred at ambient temperature for 1 hour. The reaction mixture was transferred to a glove box and filtered through a diatomaceous earth bed via a medium-porosity sintered funnel. The residue was washed with 10 mL of anhydrous hexane, and the solvent was stripped from the filtrate under full vacuum. The crude yield was 5.427 g (93%), obtained through a pure sample. 119 Sn NMR showed no detectable amount of iPr₂Sn(NMe₂)₂. Distillation of the crude product under reduced pressure (50 mTorr at pump suction) yielded 3.929 g (67%) of a colorless product. 119 Sn NMR, with 0.02% iPr2Sn(NMe2)2.

[0095] Program of Example E

[0096] Butyllithium (23.0 mL, 57.4 mmol) was added to a 100 mL round-bottom flask fitted with a PTFE-coated stir bar and diluted with 25 mL of anhydrous hexane, and fitted with a valved side-arm tubing connector. The flask was cooled to 2 °C in an ice bath, and dimethylamine (5.10 g, 113 mmol, 5.72 eq) was slowly bubbled through a 1 / 4" PTFE tubing at a rate sufficiently slow to maintain the reaction temperature at 20 °C. The reaction mixture was then stirred overnight at ambient temperature, during which time all volatiles present in the reaction mixture were evaporated via a nitrogen bubbler connected to the flask. The reaction mixture was diluted with 50 mL of hexane, cooled to approximately -10 °C in a saline bath, and allowed to undergo 4... A solution of isopropyltin trichloride (5.30 g, 19.7 mmol) diluted to 26 mL with hexane was slowly added via a syringe pump over 3 minutes (0.605 mL / min). The reaction mixture was then slowly heated to ambient temperature and stirred for 30 minutes, followed by transfer to a glove box and stirring for 60 h. The reaction mixture was filtered through a diatomaceous earth bed and washed with 15 mL of hexane. The volatiles were stripped from the filtrate under reduced pressure to give 4.73 g of crude (82%) off-white oil containing the same concentrations as a purified sample.119 Sn NMR analysis revealed 1.05% iPr₂Sn(NMe₂)₂. The material was then distilled under reduced pressure in a short-path distillation apparatus to obtain 4.019 g (69%) of a colorless oily product, which was then purified by a pure sample. 119 Sn NMR, with 1.45% iPr2Sn(NMe2)2.

[0097] Program of Instance G

[0098] Lithium dimethylamino (3.38 g, 63.3 mmol) was added to a 250 mL three-necked round-bottom flask containing a PTFE-coated stirring egg. The flask was diluted with 50 mL of anhydrous hexane and fitted with two stoppers and a 7 mm tubing connector with a valve side arm. The flask was then transferred to a gas chamber, where, under nitrogen purging, the stoppers were replaced with PTFE-coated thermocouple connectors and a condenser with a gas / vacuum inlet valve at the top. The flask was cooled to approximately -10°C in an ice-salt bath, and dimethylamine (2.9 g, 64 mmol, 3.24 eq) was slowly bubbled through a 1 / 4" PTFE tube at 16-minute intervals (0.18 g / min). The reaction mixture (still at approximately -10°C) was treated with a solution of isopropyltin trichloride (5.32 g, 19.8 mmol) diluted to 23 mL in anhydrous hexane at 46-minute intervals. The reaction mixture was then slowly warmed to ambient temperature overnight. The reaction mixture was filtered through a diatomaceous earth bed and washed with 15 mL of hexane. The filtrate was stripped under reduced pressure to give 4.86 g of crude (84%) off-white oil containing the same concentrations as a purified sample. 119 Sn NMR analysis revealed 0.5% iPr₂Sn(NMe₂)₂. The material was then distilled under reduced pressure in a short-path distillation apparatus to obtain 3.277 g (56%) of a colorless oily product, which was then purified by a pure sample. 119 Sn NMR, with 0.75% iPr2Sn(NMe2)2.

[0099] Example I program

[0100] Add 20.0 mL of butyllithium (50.0 mmol) to a 250 mL three-necked round-bottom flask containing a PTFE-coated stirring egg, dilute with 25 mL of anhydrous hexane, and mate with a 7 mm tubing connector, a 7 mm valved side arm tubing connector, and a gas / vacuum inlet connector. The flask was cooled to -4°C in a saline bath, and dimethylamine (5.11 g, 113 mmol, 6.77 eq) was slowly bubbled through a 1 / 4" PTFE tubing at 26-minute intervals (approximately 0.20 g / min). The volatiles were then stripped from the reaction mixture under reduced pressure while maintaining the reaction mixture below 8°C. When the reaction mixture had concentrated into a viscous paste, it was diluted with 50 mL of anhydrous hexane and cooled to approximately -10°C in a saline bath to prepare for the addition of the iPrSnCl3(HNMe2)2 slurry. 30 mL of hexane containing iPrSnCl3(HNMe2)2 (6.00 g, 16.7 mmol) and fitted with a stirrer was added to a 100 mL round-bottom flask equipped with a gas / vacuum inlet side arm and a 7 mm tubing connector. The two flasks were connected via a 1 / 4" PTFE tubing, and the iPrSnCl3(HNMe2)2 slurry was transferred in two aliquots. Most of the residual white solids in the 100 mL flask were washed with an additional 25 mL of anhydrous hexane, and aliquots of the reaction mixture were transferred to and from the 100 mL flask to complete the washing process and ensure complete mixing. The reaction mixture was then slowly heated in a saline bath overnight. The reaction mixture, which was a slurry of white solids in a colorless solution, was transferred to a glove box, filtered through a 1 cm diatomaceous earth bed, and washed with 10 mL of anhydrous hexane. The solvent and other volatiles were removed from the filtrate under vacuum and then collected to produce 4.310 g of crude product (87%), which contained the same amount as a pure sample. 119 Sn NMR showed iPr₂Sn(NMe₂)₂ levels below the detection limit. The material was then distilled under reduced pressure in a short-path distillation apparatus to obtain 3.541 g (72% yield) of a colorless oily product, which was then purified by a pure sample. 119 Sn NMR, with 0.03% iPr2Sn(NMe2)2.

[0101] Example K-25.0 g scale synthesis of tris(dimethylamino)isopropyltin (magnetic stirring)

[0102] Add 107.5 mL (293.6 mmol) of butyllithium diluted in hexane (24.51 mL, 186.4 mmol) to a 500 mL three-necked round-bottom flask equipped with a PTFE-coated stirrer. Fit the flask with the stopper, gas / vacuum inlet connector, and Chemglass 7 mm tubing connector with valve. Cool the flask in a brine bath and place a nitrogen-purged condenser on the flask instead of the gas / vacuum inlet connector. Then, slowly bubble dimethylamine (30.03 g, 0.661 mol, 7.14 eq) into the reaction mixture. Cool the resulting slurry to approximately -9 °C and add a solution of trichloro(propane-2-yl)stanane (25.00 g, 93.23 mmol) in hexane (122.6 mL, 932.3 mmol) (total volume 135 mL) via a 250 mL feeding funnel over 51 minutes. Once the addition was complete, the reaction mixture was heated to ambient temperature and stirred for 16 hours. The reaction mixture was then filtered through a 2 cm diatomaceous earth bed via a medium-porosity filter funnel. The filter cake was washed with hexane (24.51 mL, 186.4 mmol), and the combined filtrates were stripped under reduced pressure (50 mTorr at pump suction). The yellow oil was transferred to a pre-mixed vial, yielding 19.435 g (70.9%) of crude product. The crude product was distilled under full vacuum in a short-path distillation apparatus to give 16.945 g of a pale yellow oil (61.8% yield). 119 Sn、 1 H and 13 The distilled products were analyzed by 12C NMR, indicating the purity of the sample. 119 Sn NMR, 0.07% iPr2Sn(NMe2)2.

[0103] Example L-125.0 g scale synthesis of tris(dimethylamino)isopropyltin (mechanical stirring)

[0104] Butyllithium (540.0 mL, 1474 mmol) and hexane (525 mL) were added to a 3 L round-bottom flask equipped with a mechanical stirrer assembly and then cooled in a brine bath. Dimethylamine (120.3 g, 2.67 mol, 5.72 eq) was bubbled through the cold butyllithium solution for 273 minutes to form a viscous white slurry. To this slurry, still cooling in the brine bath, a solution of isopropyltin trichloride (125.00 g, 466.1 mmol) in hexane (610 mL) was added for 52 minutes. The reaction mixture was then filtered through a medium-porosity filter funnel via a 2 cm diatomaceous earth bed into a 2 L round-bottom flask and the residual salts were washed with hexane (125 mL). The combined filtrates were then stripped of the solvent and other volatiles under vacuum to give 126.8 g (92.6%) of crude product. The crude product was then filtered through a medium-porosity polyethylene filter funnel to remove most of the solids present. The filtered product was transferred to a clean 250 mL flask and distilled at 100 mTorr to give 116.66 g (85.1%) of distillate, which was then passed through a pure sample. 119 Sn NMR showed no detectable amount of iPr2Sn(NMe2)2.

[0105] Instance M

[0106] 2.74 M butyllithium (400 mL, 1096 mmol) and hexane (400 mL) were added to a 3 L round-bottom flask equipped with a mechanical stirrer assembly and then cooled in an isopropanol / ice bath. Dimethylamine (66.3 g, 4.224 mol) was bubbled through the cold butyllithium solution to form a viscous white slurry. The dimethylaminolithium reaction mixture was then diluted with 871 mL of anhydrous tetrahydrofuran to form a less viscous but still heterogeneous reaction mixture. Additional dimethylamine (66.0 g, 4.204 mol) was added to this cooled slurry to obtain a homogeneous solution. After 199 minutes, a solution of isopropyltin bis(dimethylamine) trichloride (125.00 g, 348 mmol) in anhydrous tetrahydrofuran was added to this solution, which was still being cooled in an isopropanol / water bath, with the internal reaction temperature between -18 °C and -13 °C. The reaction mixture was slowly heated to ambient temperature over 18 hours. The solvent and other volatiles were stripped from the reaction mixture under vacuum. The mixture was diluted with 250 mL of anhydrous hexane, filtered through a medium-porosity sintered funnel, and then washed with an additional 250 mL of anhydrous hexane. The combined filtrate was then stripped of hexane and other volatiles under vacuum to give 101.1 g (99%) of crude product. The crude product was distilled at 70–100 mTorr to give 88.8 g (87%) of distillate, which was then purified by a pure sample. 119 Sn NMR showed no detectable amount of iPr2Sn(NMe2)2.

[0107] Table 1A. Method variables in the synthesis of tris(dimethylamino)isopropyltin

[0108]

[0109] *DMA = dimethylamine

[0110] **Isopropyltin trichloride

[0111] ***In Examples A through G, tin starting materials were prepared via an iPr4Sn / SnCl4 redistribution reaction; in Example H, tin starting materials were prepared via an iPrSn(phenyl)3 redistribution reaction; and in Example I, tin starting materials were prepared via iPrSn(phenyl)3 redistribution followed by reaction with excess dimethylamine and separation of the Lewis base adduct of formula (A). ****In Examples A, B, and G, LiNMe2 was commercially available as a dry solid and used as is. In Example E, LiNMe2 was synthesized, but all volatiles containing any excess dimethylamine were evaporated over a 16-hour period at saturation. *****In Example I, volatiles (excess DMA and hexane) were stripped off under vacuum to ensure no excess dimethylamine residue remained. ******In Example B, triethylamine was used as a synthetic additive in the preparation of isopropyl(tri)dimethylamine tin; in all other examples, no synthetic additives were used.

[0112] Table 1B. Method Variables (continued)

[0113]

[0114] Example J (a comparative example of Example 1 in WO2017 / 066319)

[0115] Lithium dimethylamino (3.03 g, 59.5 mmol, Sigma-Aldrich) and 25 mL of hexane were added to a 100 mL round-bottom flask. The flask was equipped with a PTFE-coated stir bar and a thermocouple / connector, and then cooled in a dry ice / isopropanol bath (-73 °C internal temperature). Trichloro(prop-2-yl)stanane (5.00 g, 18.6 mmol) was added to the slurry via a syringe pump over 122 minutes. The reaction mixture was then heated to ambient temperature and stirred for 16 h. The reaction mixture was filtered through a diatomaceous earth bed onto a medium-porosity glass frit. The filter cake was washed with 25 mL of anhydrous hexane, and the volatiles were stripped from the filtrate under full vacuum. The crude product was distilled under full vacuum to give 3.52 g (64.4%) of a colorless oil. 119 Sn NMR spectroscopy indicates the presence of approximately 1.6% iPr2Sn(NMe2)2.

[0116] Preparation 1-Synthesis of Isopropyl-SnCl3 from Isopropyl-Sn(phenyl)3 and SnCl4

[0117] 753 g (1.915 mol) of isopropyltriphenyltin was charged into a 2- or 3-necked distillation flask equipped with a thermocouple and fitted with an 8" Vigréaux column distillation assembly. A 1 L flask was fitted with the distillation outlet. At approximately two-hour intervals, 1000 g of tin(IV) chloride (3.838 mol, 2 eq, Sigma-Aldrich) was charged into the flask containing isopropyltriphenyltin, during which moderate exothermic reaction was observed. Isopropyltin trichloride was then distilled at 1 Torr between 65°C and 75°C, with the head temperature rising sharply to approximately 100°C at the end of distillation. The product (588 g) was found to be a mixture of PhSnCl3 (15 mol%) and iPrSnCl3 (85 mol%), obtained by... 119 Sn NMR was performed using a distillation vessel composed of 55 mol% Ph₂SnCl₂ and 45 mol% PhSnCl₃. The yield of iPrSnCl₃, calculated from the relative NMR integral, was 493 g (96% yield). Further distillation was conducted at 50–100 mTorr head temperatures of 40–43 °C using a 0.16 inch stainless steel encapsulation. The mixture of iPrSnCl3 and PhSnCl3 was distilled by column 1' to obtain 461 g (90%) iPrSnCl3, by... 119 Sn NMR, with a purity of 99.9%.

[0118] 1 H NMR (400MHz, CDCl3, 298K): d 1.61 (sept, 1H), 1.38 (d, 6H) ppm. 13 C{ 1 H}NMR (100MHz, CDCl3 289K): d 40.9, 19.7ppm. 119 Sn{ 1 H}NMR (149MHz CDCl3,298K): d-5.9ppm.

[0119] Preparation of 2-isopropyl-SnCl3 from (phenyl)3Sn-isopropyl and ICl

[0120] A 100 mL round-bottom flask equipped with a PTFE-coated stir bar was filled with isopropyltriphenyltin (10.00 g, 25.43 mmol), 50 mL of anhydrous hexane, and iodine monochloride (12.42 g, 76.54 mmol) was added dropwise with stirring. The temperature increased from 22 °C to 71 °C over a 10-minute addition period. The reaction mixture was then stirred at ambient temperature for 18 h. 119Sn NMR analysis of aliquots of the reactants indicated the presence of a small amount of iPrSnPhCl₂. The reaction mixture was treated with iodine monochloride (2.063 g, 12.71 mmol) (additionally 0.5 eq) and then stirred at ambient temperature for 30 min. The solvent was then removed under 10 Torr vacuum to obtain the crude product (22.439 g, a mixture of the desired product and iodobenzene). The mixture was then encapsulated in a 0.16 square inch stainless steel container. The product was distilled using a 6" 14 / 20 distillation column to obtain three eluates: eluate 1 - 8.86 g, 8.4 mol% iPrSnCl3; eluate 2 - 7.08 g, 36.9 mol% iPrSnCl3; and eluate 3 - 4.86 g, 93.8 mol% iPrSnCl3. Overall, the recovery of iPrSnCl3 was quantitative.

[0121] Preparation of 3-isopropyl SnI3 from Ph3Sn-isopropyl and I2

[0122] Isopropyltriphenyltin (5.00 g, 12.7 mmol) and 20 mL of toluene were added to a 40 mL vial. Iodine (10.2 g, 40.0 mmol) was slowly added in portions, with exothermic reactions observed after each addition. The resulting deep red mixture was then heated at 90 °C for 16 h. The resulting solution was then distilled under vacuum in a short-path apparatus to first remove the iodobenzene byproduct, and then the product was distilled in 94% yield (100 to 105 °C head temperature, 200 to 500 mTorr) as a yellow oil.

[0123] 1 ¹H NMR (400MHz, benzene-d6, 298K): d 1.78 (sept, 1H), 0.61 (d, 6H) ppm. 13 C{ 1 ¹H NMR (100MHz, benzene-d6, 289K): d 37.6, 19.8ppm. 119 Sn{ 1 ¹H NMR (149MHz, benzene-d6, 298K): d-434ppm.

[0124] EtSnCl3 - Synthesis and Purification

[0125] Ph3SnEt (637.8 g, 1.68 mol) was loaded into a 2L round-bottom flask with a four-necked neck, equipped with a magnetic stir bar, thermocouple, and nitrogen inlet connector. SnCl4 (916 g, 3.52 mol) was placed in a 500 mL feeding funnel in a nitrogen-filled glove box, which was then removed from the glove box and connected to the 2L round-bottom flask. The apparatus was placed under N2 atmosphere, and SnCl4 was slowly added directly to the solid Ph3SnEt over 8 hours. The reaction mixture was heated to 115°C for 1 hour and then distilled at 1 tor at 67°C to 69°C using a jacketed 8" Wiegler column. 2 to 3 mL of forecut was collected, and distillation was stopped when the head temperature reached 78°C. A second distillation was performed at 1 tor with a head temperature of approximately 64°C using an 8" column encapsulated with a glass Raschig ring to give EtSnCl3 (327.16 g, 108 mol, 76.7% yield) as a colorless liquid with a purity >99.0%. 1 H-NMR (400MHz, C6D6, 298K): 1.43 (t, 3H); 2.27 (q, 2H) ppm; 119 Sn NMR (149MHz, 298K): 2.03ppm.

[0126] Synthesis and Characterization of EtSnCl3(HNMe2)2-

[0127] A 5L, 3-necked jacketed flask equipped with a top stirrer, inlet connector, and thermocouple was introduced into a nitrogen-filled glove box. EtSnCl3 (391g, 1.53mol) was placed in the flask and diluted with 3L of hexane. HNMe2 was bubbled into the reaction flask at a rate of approximately 1.0g / min. After a 4-hour time course, HNMe2 (149.3g, 3.30mol) was added, accompanied by an exothermic reaction at approximately 20°C, resulting in the formation of a white precipitate. The reaction mixture was stirred at room temperature for approximately 18h, filtered through a medium-porosity glass frit, washed with 500mL of hexane, and dried under vacuum to give 477g of a slightly viscous white solid (90.7%) with a purity >99.0%. 1 H-NMR (400MHz, CDCl3, 298K): 1.28 (t, 3H); 1.75 (q, 2H); 2.77 (s, 12H); 3.44 (s, 2H) ppm; 13 C-NMR (100MHz, CDCl3, 298K): 12.75, 29.61, 38.88ppm; 119 Sn-NMR (149MHz CDCl3, 298K): -394.5ppm.

[0128] EtSn(NMe2)3-Synthesis and Purification

[0129] nBuLi (2.5M, 1.73L, 4.34mol) diluted in 3L hexane was added to a 12L four-necked flask equipped with a mechanical stirrer assembly. The nBuLi solution was then cooled to an internal temperature of 0°C using an IPA / liquid N2 bath. Dimethylamine gas was bubbled into the reactants at a rate of approximately 1 g / min over a period of 5 hours, with the internal reaction temperature below 3°C, resulting in a viscous white mixture. The LiNMe2 reaction mixture was heated to room temperature and stirred for approximately 72 hours. The LiNMe2 mixture was cooled to approximately -2°C using an IPA / N2 bath, and then treated with a solution of EtSnCl3(HNMe2)2 (477g, 1.38mol) in 3L dimethoxyethylene at an internal reaction temperature of approximately 1 to 2°C over a period of 2.5 hours in the dark (all subsequent steps were also carried out in the dark), resulting in a pale yellow solution. This solution was stirred at ambient temperature for approximately 18 hours. The solvent and other volatiles of the pale yellow reaction mixture were stripped under vacuum to give a viscous, off-white / yellow solid. This solid was slurried in 3 L of hexane and filtered through a medium-porosity glass frit. The filtrate was then stripped under vacuum to give hexane and other volatiles to give an orange oily product as a crude product. The crude product was distilled using a 10" Wiegler column at pressures ranging from 200 to 500 mTorr and head temperatures from 28 to 35 °C. The first 10 mL fraction was discarded, and the major eluent (278 g, 0.99 mol, 72% yield) of EtSn(NMe2)3 as a colorless liquid was collected with 99.84% purity. 1 H-NMR (400MHz, C6D6, 298K): 0.99 (q, 2H); 1.15 (t, 3H); 2.73 (s, 18H) ppm; 13 C-NMR (100MHz, C6D6, 298K): 4.32, 10.14, 43.27ppm; 119 Sn-NMR (149MHz, C6D6, 298K): -38.48ppm.

[0130] Crystal structure data

[0131] As pointed out above, Figure 1 A description of the three-dimensional solid-state crystal structure of iPrSnCl3(HN(CH3)2)2 is provided. The compound was subjected to X-ray crystallization analysis, yielding the following data:

[0132] Table 2

[0133]

[0134]

[0135] Furthermore, as pointed out above, Figure 2 A description of the three-dimensional solid-state crystal structure of EtSnCl3(HN(CH3)2)2 is provided. The compound was subjected to X-ray crystallization analysis, yielding the following data:

[0136] Table 3

[0137]

[0138] In a first aspect, the present invention provides a composition comprising a compound of formula (I):

[0139]

[0140] Each R is independently selected from C1-C5 alkyl groups, and R 1 Selected from C1-C5 alkyl groups, wherein the composition comprises a compound of formula (II) at a concentration of less than about 0.5 mol%:

[0141]

[0142] In a second aspect, the present invention provides a composition of the first aspect, wherein R and R 1 Independently selected from C1-C3 alkyl groups.

[0143] In a third aspect, the present invention provides a composition of the first or second aspect, wherein the compound of formula (I) is tris(dimethylamino)isopropyltin; tris(diethylamino)isopropyltin; tris(dipropylamino)isopropyltin; tris(methylethylamino)isopropyltin; tris(diisopropylamino)isopropyltin; tris(di-tert-butylamino)isopropyltin; tris(di-n-butylamino)isopropyltin; tris(di-sec-butylamino)isopropyltin; tris(di-neopentylamino)isopropyltin; Tris(dimethylamino)methyltin; Tris(diethylamino)methyltin; Tris(di-n-propylamino)methyltin; Tris(methylethylamino)methyltin; Tris(diisopropylamino)methyltin; Tris(di-tert-butylamino)methyltin; Tris(di-n-butylamino)methyltin; Tris(di-sec-butylamino)methyltin; Tris(di-neopentylamino)methyltin; Tris(dimethylamino)ethyltin; Tris(diethylamino)ethyltin; Tris(di-n-propylamino)ethyltin; Tris(methylethylamino)methyltin Tris(diisopropylamino)ethyltin; Tris(di-tert-butylamino)ethyltin; Tris(di-n-butylamino)ethyltin; Tris(di-sec-butylamino)ethyltin; Tris(di-neopentylamino)ethyltin; Tris(dimethylamino)n-propyltin; Tris(diethylamino)n-propyltin; Tris(di-n-propylamino)n-propyltin; Tris(methylethylamino)n-propyltin; Tris(diisopropylamino)n-propyltin; Tris(di-tert-butylamino)n-propyltin; Tris(di-n-butylamino)n-propyltin Tris(di-sec-butylamino)-propyltin; Tris(di-neopentylamino)-propyltin; Tris(dimethylamino)-butyltin; Tris(diethylamino)-butyltin; Tris(dipropylamino)-butyltin; Tris(dimethylethylamino)-butyltin; Tris(diisopropylamino)-butyltin; Tris(di-tert-butylamino)-butyltin; Tris(di-n-butylamino)-butyltin; Tris(di-sec-butylamino)-butyltin; or Tris(di-neopentylamino)-butyltin.

[0144] In a fourth aspect, the present invention provides a composition as described in any one of the first to third aspects, wherein the compound of formula (I) is tris(dimethylamino)isopropyltin; tris(diethylamino)isopropyltin; tris(dipropylamino)isopropyltin; tris(methylethylamino)isopropyltin; tris(diisopropylamino)isopropyltin; tris(di-tert-butylamino)isopropyltin; tris(di-n-butylamino)isopropyltin; tris(di-sec-butylamino)isopropyltin; or tris(di-neopentylamino)isopropyltin.

[0145] In a fifth aspect, the present invention provides a composition as described in any one of the first to fourth aspects, wherein the compound of formula (I) is tris(dimethylamino)isopropyltin and the compound of formula (II) is bis(dimethylamino)diisopropyltin.

[0146] In a sixth aspect, the present invention provides a composition as described in any one of the first to fifth aspects, wherein the compound of formula (II) is present at a concentration of less than about 0.1 mol%.

[0147] In a seventh aspect, the present invention provides a composition as described in any one of the first to sixth aspects, wherein the compound of formula (II) is present at a concentration of less than about 0.05 mol%.

[0148] In an eighth aspect, the present invention provides a composition as described in any one of the first to seventh aspects, wherein the compound of formula (II) is present at a concentration of less than about 0.03 mol%.

[0149] In a ninth aspect, the present invention provides a method for preparing a composition comprising a compound of formula (I):

[0150]

[0151] Each R is independently selected from C1-C5 alkyl groups, and R 1 Selected from C1-C5 alkyl groups, the method includes combining the following:

[0152] a) Equation R 1 The SnX3 compound, wherein X is selected from Cl, I, and Br.

[0153] b) Li(R)₂N compound, and

[0154] c) R2NH compound,

[0155] The compound of formula R2NH is compared to the compound of formula R 1 The SnX3 compound exists in molar excess.

[0156] In a tenth aspect, the present invention provides a method according to the ninth aspect, wherein R and R 1 It is independently selected from C1-C3 alkyl groups.

[0157] In an eleventh aspect, the present invention provides a method according to the ninth or tenth aspect, wherein R 1 It is isopropyl and X is chlorine.

[0158] In a twelfth aspect, the present invention provides a method as described in any one of the ninth to eleventh aspects, wherein the compound of formula (I) is tris(dimethylamino)isopropyltin; tris(diethylamino)isopropyltin; tris(dipropylamino)isopropyltin; tris(dimethylethylamino)isopropyltin; tris(diisopropylamino)isopropyltin; tris(di-tert-butylamino)isopropyltin; tris(di-n-butylamino)isopropyltin; tris(di-sec-butylamino)isopropyltin; tris(di-neopentylamino)isopropyltin Tris(dimethylamino)methyltin; Tris(diethylamino)methyltin; Tris(di-n-propylamino)methyltin; Tris(methylethylamino)methyltin; Tris(diisopropylamino)methyltin; Tris(di-tert-butylamino)methyltin; Tris(di-n-butylamino)methyltin; Tris(di-sec-butylamino)methyltin; Tris(di-neopentylamino)methyltin; Tris(dimethylamino)ethyltin; Tris(diethylamino)ethyltin; Tris(di-n-propylamino)ethyltin; Tris(dimethylamino)ethyltin Tris(diisopropylamino)ethyltin; Tris(di-tert-butylamino)ethyltin; Tris(di-n-butylamino)ethyltin; Tris(di-sec-butylamino)ethyltin; Tris(di-neopentylamino)ethyltin; Tris(dimethylamino)n-propyltin; Tris(diethylamino)n-propyltin; Tris(di-n-propylamino)n-propyltin; Tris(di-n-butylamino)n-propyltin; Tris(dimethylethylamino)n-propyltin; Tris(diisopropylamino)n-propyltin; Tris(di-tert-butylamino)n-propyltin; Tris(di-n-butylamino)n-propyltin Tris(di-sec-butylamino)-propyltin; Tris(di-neopentylamino)-propyltin; Tris(dimethylamino)-n-butyltin; Tris(diethylamino)-n-butyltin; Tris(dipropylamino)-n-butyltin; Tris(methylethylamino)-n-butyltin; Tris(diisopropylamino)-n-butyltin; Tris(di-tert-butylamino)-n-butyltin; Tris(di-n-butylamino)-n-butyltin; Tris(di-sec-butylamino)-n-butyltin; or Tris(di-neopentylamino)-n-butyltin.

[0159] In a thirteenth aspect, the present invention provides a method as described in any of the ninth to twelfth aspects, wherein the compound of formula (I) is selected from tris(dimethylamino)isopropyltin; tris(diethylamino)isopropyltin; tris(dipropylamino)isopropyltin; tris(methylethylamino)isopropyltin; tris(diisopropylamino)isopropyltin; tris(di-tert-butylamino)isopropyltin; tris(di-n-butylamino)isopropyltin; tris(di-sec-butylamino)isopropyltin; and tris(di-neopentylamino)isopropyltin.

[0160] In a fourteenth aspect, the present invention provides a method as described in any one of aspects nine to thirteen, wherein the compound of formula R2NH is a dimethylamine and R 1 It is isopropyl.

[0161] In a fifteenth aspect, the present invention provides a method as described in any one of aspects nine to fourteen, wherein the compound of formula Li(R)₂N is lithium dimethylamino, the compound of formula R₂NH is dimethylamine, and the compound of formula R 1 The SnX3 compound is isopropyltin trichloride.

[0162] In a sixteenth aspect, the present invention provides a method as described in the fifteenth aspect, wherein the composition comprises less than about 0.5% bis(dimethylamino)diisopropyltin.

[0163] In a seventeenth aspect, the present invention provides a method as described in the fifteenth or sixteenth aspect, wherein the composition comprises less than about 0.1% bis(dimethylamino)diisopropyltin.

[0164] In an eighteenth aspect, the present invention provides a method as described in any of the fifteenth to seventeenth aspects, wherein the composition comprises less than about 0.05% bis(dimethylamino)diisopropyltin.

[0165] In a nineteenth aspect, the present invention provides a method as described in any one of the ninth to eighteenth aspects, wherein the compound of formula R2NH is compared to that of formula R 1 The SnX3 compound was present in a quantity of at least about 0.15 molar equivalents.

[0166] In a twentieth aspect, the present invention provides a method as described in any of the ninth to nineteenth aspects, wherein the compound of formula (I) is prepared from the compound of formula (A):

[0167]

[0168] In a twenty-first aspect, the present invention provides a method as described in the twentieth aspect, wherein the compound of formula (A) is prepared by reacting the compound of formula R2NH with formula R 1 The preparation is carried out by reacting SnX3 compounds, wherein the R2NH compound is in greater quantity than the R... 1 SnX3 compounds.

[0169] In a twenty-second aspect, the present invention provides a method as described in the twentieth or twenty-first aspect, wherein the compound of formula (I) is prepared by reacting the compound of formula (A) with the compound of formula Li(R)₂N.

[0170] In a twenty-third aspect, the present invention provides a method as described in any of the twenty to twenty-second aspects, wherein the compound of formula Li(R)₂N is present in a molar excess of about 3 to about 3.2 molar equivalents relative to the compound of formula (A).

[0171] In a twenty-fourth aspect, the present invention provides a method as described in any one of the twenty to twenty-third aspects, wherein the compound of formula (I) is a compound of formula (Ia):

[0172]

[0173] The compound of formula (A) is a compound of formula (Aa):

[0174]

[0175] Furthermore, the compound of formula Li(R)2N is lithium dimethylamino.

[0176] In a twenty-fifth aspect, the present invention provides a method as described in any one of the twenty to twenty-third aspects, wherein the compound of formula (I) is a compound of formula (Id):

[0177]

[0178] The compound of formula (A) is a compound of formula (Ad):

[0179]

[0180] Furthermore, the compound of formula Li(R)2N is lithium dimethylamino.

[0181] In a twenty-sixth aspect, the present invention provides a method as described in any one of the twenty to twenty-fifth aspects, wherein the formula R 1 SnX3 compounds are obtained by making the formula R 1 SnR 4 The three compounds are prepared by reacting them with monoiodide chloride or bromide, respectively, wherein X is chlorine or bromine and R... 1 Selected from C1-C5 alkyl groups, wherein R 4 Selected from aryl, C2-C8 alkenyl and C2-C8 alkynyl.

[0182] In a twenty-seventh aspect, the present invention provides a method as described in any one of the twenty to twenty-fifth aspects, wherein the formula R 1 SnX3 compounds are produced by using formula R 1 SnR 2 The compound is prepared by contacting it with a compound of formula SnX4, wherein X is chlorine, bromine, or iodine and R... 1 Selected from C1-C5 alkyl groups, wherein R 2 Selected from aryl or C2-C8 alkenyl groups.

[0183] In a twenty-eighth aspect, the present invention provides a compound of formula (Aa):

[0184]

[0185] In a twenty-ninth aspect, the present invention provides a compound as described in the twenty-eighth aspect, which is as follows: Figure 1 The crystalline form described in the text.

[0186] In a thirtieth aspect, the present invention provides a compound of formula (Ad):

[0187]

[0188] In a thirty-first aspect, the present invention provides a compound as described in the thirty-first aspect, which presents as follows: Figure 2 The crystalline form described in the text.

[0189] In a thirty-second aspect, the present invention provides a method for preparing formula R 1 A method for SnX3 compounds, wherein X is chlorine or bromine and R... 1 Selected from C1-C5 alkyl groups, the method includes making formula R 1 SnR 4 The three compounds react with monoiodide chloride or bromide, respectively, where R 4 Selected from aryl, C2-C8 alkenyl and C2-C8 alkynyl.

[0190] In a thirty-third aspect, the present invention provides a method for preparing formula R 1 A method for SnX3 compounds, wherein X is chlorine, bromine, or iodine and R... 1 Selected from C1-C5 alkyl groups, the method includes making formula R 1 SnR 2 Compound 3 is contacted with compound of formula SnX4, wherein R 2 Selected from aryl or C2-C8 alkenyl groups.

[0191] Therefore, given the description of several illustrative embodiments of the invention, those skilled in the art will readily understand that other embodiments can be made and used within the scope of the appended claims. Many advantages of the invention as covered in this document have been set forth in the foregoing description. However, it will be understood that the invention is illustrative in many respects only. Of course, the scope of the invention is defined by the language of the appended claims.

Claims

1. A method for preparing a composition comprising a compound of formula (I): wherein each R is independently selected from C1-C5 alkyl, and R 1 selected from C1-C5 alkyl, the method comprising combining: a) Equation R 1 The SnX3 compound, wherein X is selected from Cl, I, and Br. b) Li(R)₂N compound, and c) R2NH compound, The compound of formula R2NH is compared to the compound of formula R 1 The SnX3 compound exists in molar excess.

2. The method according to claim 1, wherein the compound of formula (I) is tris(dimethylamino)isopropyltin; tris(diethylamino)isopropyltin; tris(dipropylamino)isopropyltin; tris(methylethylamino)isopropyltin; tris(diisopropylamino)isopropyltin; tris(di-tert-butylamino)isopropyltin; tris(di-n-butylamino)isopropyltin; tris(di-sec-butylamino)isopropyltin; tris(di-neopentylamino)isopropyltin; tris(dimethylamino)isopropyltin Methyltin; Tris(diethylamino)methyltin; Tris(di-n-propylamino)methyltin; Tris(methylethylamino)methyltin; Tris(diisopropylamino)methyltin; Tris(di-tert-butylamino)methyltin; Tris(di-n-butylamino)methyltin; Tris(di-sec-butylamino)methyltin; Tris(di-neopentylamino)methyltin; Tris(dimethylamino)ethyltin; Tris(diethylamino)ethyltin; Tris(di-n-propylamino)ethyltin; Tris(methylethylamino)ethyltin Tris(diisopropylamino)ethyltin; Tris(di-tert-butylamino)ethyltin; Tris(di-n-butylamino)ethyltin; Tris(di-sec-butylamino)ethyltin; Tris(di-neopentylamino)ethyltin; Tris(dimethylamino)n-propyltin; Tris(diethylamino)n-propyltin; Tris(di-n-propylamino)n-propyltin; Tris(methylethylamino)n-propyltin; Tris(diisopropylamino)n-propyltin; Tris(di-tert-butylamino)n-propyltin; Tris(di-n-butylamino)n-propyltin ) n-Propyltin; tris(di-sec-butylamino)n-propyltin; tris(di-neopentylamino)n-propyltin; tris(dimethylamino)n-butyltin; tris(diethylamino)n-butyltin; tris(dipropylamino)n-butyltin; tris(methylethylamino)n-butyltin; tris(diisopropylamino)n-butyltin; tris(di-tert-butylamino)n-butyltin; tris(di-n-butylamino)n-butyltin; tris(di-sec-butylamino)n-butyltin; or tris(di-neopentylamino)n-butyltin.

3. The method according to claim 1, wherein the compound of formula (I) is prepared from the compound of formula (A), and wherein the compound of formula (A) is prepared by reacting the compound of formula R2NH with the compound of formula R 1 Prepared by reacting SnX3 compounds: #imgpt1#(A).

4. The method according to claim 3, wherein the compound of formula (I) is prepared by reacting the compound of formula (A) with the compound of formula Li(R)₂N.

5. The method according to claim 3, wherein the Li(R)₂N compound is present in a molar excess of 3 to 3.2 molar equivalents relative to the compound of formula (A).

6. The method according to claim 1, wherein formula R 1 SnX3 compounds are produced by using formula R 1 SnR 4 The three compounds are prepared by reacting them with monoiodine chloride or bromide, respectively, wherein X is chlorine or bromine and R... 1 Selected from C1-C5 alkyl groups, wherein R 4 Selected from aryl, C2-C8 alkenyl and C2-C8 alkynyl.

7. The method according to claim 1, wherein formula R 1 SnX3 compounds are produced by using formula R 1 SnR 2 The compound is prepared by contacting it with a compound of formula SnX4, wherein X is chlorine, bromine, or iodine and R... 1 Selected from C1-C5 alkyl groups, wherein R 2 Selected from aryl or C2-C8 alkenyl groups.

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