Catalytic preparation of disilanes

Abstract

A catalyst of formula (I) where Ar is a substituted or unsubstituted aryl group; and E1 and E2 are, individually, a moiety having a double or triple bond, or where E1 and E2 join together to form a cyclic structure with the Ni to which they are bound.

Description

Atty. Dkt. No.: 114198-3210 CATALYTIC PREPARATION OF DISILANES CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No.63 / 696,219, filed on September 18, 2024, which is incorporated herein by reference in its entirety. FIELD

[0002] The present technology is generally related to selective methods for making di‐ and tri‐silanes from monosilanes. SUMMARY

[0003] In one aspect, provided is a catalyst of formula (I):Where Ar is a substituted or unsubstituted aryl group; and E1and E2are, individually, a moiety having a double or triple bond, or where E1and E2join together to form a cyclic structure with the Ni to which they are bound.

[0004] In another aspect, a method for making a catalyst of formula (I) includes contacting a Ni0compound of formula NiE1E2E3E4, where E1, E2, E3, and E4are, individually, a moiety having a double or triple bond, or where E1and E2and / or E3and E4join together to form a cyclic structure with the Ni to which they are bound, and an isocyanide of formula ArNC, where Ar is a substituted or unsubstituted aryl group, to obtain a crude product, and purifying the crude product to obtain an isolated product of formula (I). The isocyanide may be CN(2,6-(2,4,6-(CH(CH3)2)3C6H2)2C6H3) or 2,2'',4,4'',6,6''-hexa-tert-butyl-[1,1':3',1''-terphenyl]-2'-yl)(methylidyne)-^4-azane. The compound of the compound of formula NiE1E2E3E4may be Ni(COD)2. 1 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0005] In another aspect, a process for producing a second silane from a first silane includes contacting the first silane of formula RSiH3with the catalyst of formula (I), where R is H, alkyl, or aryl, and the second silane is a dimer or higher order silane of the first silane.

[0006] In another aspect, a compound is provided, the compound being (2,2'',4,4'',6,6''-hexa-tert-butyl-[1,1':3',1''-terphenyl]-2'-yl)(methylidyne)-^4-azane.

[0007] In a further aspect, a method of making any of the catalysts described herein is provided, and includes contacting (i) a Ni0compound of formula NiE1E2E3E4, where E1, E2, E3, and E4are, individually, a moiety having a double or triple bond, or where E1and E2and / or E3and E4join together to form a cyclic structure with the Ni to which they are bound, and (ii) an isocyanide of formula ArNC, where Ar is a substituted or unsubstituted aryl group, to obtain a crude product; and purifying the crude product to obtain an isolated product of formula (I). DETAILED DESCRIPTION

[0008] Various embodiments are described hereinafter. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation to the broader aspects discussed herein. One aspect described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced with any other embodiment(s).

[0009] As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the terms that are not clear to persons of ordinary skill in the art, given the context in which it is used, the terms will be plus or minus 10% of the disclosed values. When “approximately,” “about,” “substantially,” and similar terms are applied to a structural feature (e.g., to describe its shape, size, orientation, direction, etc.), these terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should 2 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0010] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the elements (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the claims unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential.

[0011] In general, “substituted” refers to an alkyl, alkenyl, alkynyl, aryl, or ether group, as defined below (e.g., an alkyl group) in which one or more bonds to a hydrogen atom contained therein are replaced by a bond to non-hydrogen or non-carbon atoms. Substituted groups also include groups in which one or more bonds to a carbon(s) or hydrogen(s) atom are replaced by one or more bonds, including double or triple bonds, to a heteroatom. Thus, a substituted group will be substituted with one or more substituents, unless otherwise specified. In some embodiments, a substituted group is substituted with 1, 2, 3, 4, 5, or 6 substituents. Examples of substituent groups include: halogens (i.e., F, Cl, Br, and I); hydroxyls; alkoxy, alkenoxy, alkynoxy, aryloxy, aralkyloxy, heterocyclyloxy, and heterocyclylalkoxy groups; carbonyls (oxo); carboxyls; esters; urethanes; oximes; hydroxylamines; alkoxyamines; aralkoxyamines; thiols; sulfides; sulfoxides; sulfones; sulfonyls; sulfonamides; amines; N-oxides; hydrazines; hydrazides; hydrazones; azides; amides; ureas; amidines; guanidines; enamines; imides; isocyanates; isothiocyanates; cyanates; thiocyanates; imines; nitro groups; nitriles (i.e., CN); and the like. 3 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0012] As used herein, “alkyl” groups include straight chain and branched alkyl groups having from 1 to about 20 carbon atoms, and typically from 1 to 12 carbons or, in some embodiments, from 1 to 8 carbon atoms. As employed herein, “alkyl groups” include cycloalkyl groups as defined below. Alkyl groups may be substituted or unsubstituted. Examples of straight chain alkyl groups include methyl, ethyl, n-propyl, n- butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples of branched alkyl groups include, but are not limited to, isopropyl, sec-butyl, t-butyl, neopentyl, and isopentyl groups. Representative substituted alkyl groups may be substituted one or more times with, for example, amino, thio, hydroxy, cyano, alkoxy, and / or halo groups such as F, Cl, Br, and I groups. As used herein the term haloalkyl is an alkyl group having one or more halo groups. In some embodiments, haloalkyl refers to a per-haloalkyl group.

[0013] Cycloalkyl groups are cyclic alkyl groups such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, the cycloalkyl group has 3 to 8 ring members, whereas in other embodiments the number of ring carbon atoms range from 3 to 5, 6, or 7. Cycloalkyl groups may be substituted or unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphenyl, isocamphenyl, and carenyl groups, and fused rings such as, but not limited to, decalinyl, and the like. Cycloalkyl groups also include rings that are substituted with straight or branched chain alkyl groups as defined above. Representative substituted cycloalkyl groups may be mono-substituted or substituted more than once, such as, but not limited to: 2,2-; 2,3-; 2,4-; 2,5-; or 2,6-disubstituted cyclohexyl groups or mono-, di-, or tri- substituted norbornyl or cycloheptyl groups, which may be substituted with, for example, alkyl, alkoxy, amino, thio, hydroxy, cyano, and / or halo groups. Cyclodienes include cyclic compounds having two olefin, or alkenyl, groups in the ring. Examples include, but are not limited to, cyclooctadiene (“COD”).

[0014] Alkenyl (i.e. “ene”) groups are straight chain, branched or cyclic alkyl groups having 2 to about 20 carbon atoms, and further including at least one double bond. In some embodiments alkenyl groups have from 1 to 12 carbons, or, typically, from 1 to 8 carbon atoms. Alkenyl groups may be substituted or unsubstituted. Alkenyl groups include, for instance, vinyl, propenyl, 2-butenyl, 3-butenyl, isobutenyl, cyclohexenyl, cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienyl groups among 4 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 others. Alkenyl groups may be substituted similarly to alkyl groups. Divalent alkenyl groups, i.e., alkenyl groups with two points of attachment, include, but are not limited to, CH-CH=CH2, C=CH2, or C=CHCH3.

[0015] As used herein, “aryl,” or “aromatic,” groups are cyclic aromatic hydrocarbons that do not contain heteroatoms. Aryl groups include monocyclic, bicyclic and polycyclic ring systems. Thus, aryl groups include, but are not limited to, phenyl, azulenyl, heptalenyl, biphenylenyl, indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenyl, naphthacenyl, chrysenyl, biphenyl, anthracenyl, indenyl, indanyl, pentalenyl, and naphthyl groups. In some embodiments, aryl groups contain 6-14 carbons, and in others from 6 to 12 or even 6-10 carbon atoms in the ring portions of the groups. The phrase “aryl groups” includes groups containing fused rings, such as fused aromatic-aliphatic ring systems (e.g., indanyl, tetrahydronaphthyl, and the like). Aryl groups may be substituted or unsubstituted.

[0016] The present inventors have now found and developed processes for a low‐temperature, energy efficient, and synthesis of di‐ and tri‐silanes from monosilanes. The processes include the use of molecular catalysts that can selectively couple monosilanes to form mixtures of di-silane(s) and tri-silane(s). The catalysts may include a transition metal catalyst and proceed according to the following general scheme:In some embodiments, the transition metal catalyst comprises nickel. In other embodiments, the nickel catalyst may be a hindered, nickel-based catalyst having isocyanide (e.g. isonitrile) aryl ligands, and the nickel center (Ni) is Ni0. Without being bound by theory, it is believed that the sterically hindered nickel complexes disclosed herein, allow for dimerization and trimerization of the monosilanes, while preventing the further oligomerization that has plagued other methods of formation. The process form the di- and tri-silanes without further olio- or poly-silane formation, and the di- and tri- silanes that are formed are readily separable from one another. Such di‐ and tri‐silanes are reactive entities used in conformal growth of silicon oxide (i.e. SiO2), silicon nitride (i.e. Si3N4), and / or silicon carbide dielectric materials through atomic layer deposition (ALD). 5 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0017] In one aspect, a catalyst of formula (I) is provided:In formula (I), Ar may be a substituted or unsubstituted aryl group; and E1and E2may individually represent a moiety having a double or triple bond, or where E1and E2join together to form a cyclic structure with the Ni to which they are bound. In some embodiments, Ar is aryl or heteroaryl. In some embodiments, Ar is a group of formula:.

[0018] Where Ar is a group of the above formula, the R1, R2, R3, R4, and R5groups may each be independently H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl, or any two adjacent groups may fuse to form a ring that is substituted or unsubstituted. In some embodiments, R1and R5are substituted aryl and R2, R3, and R4are each H. In further embodiments, R1and R5are each (2,4,6-(i-Pr)3C6H2)2C6H3 or (2,4,6-(t- Bu)3C6H2)2C6H3, where i-Pr is -CH(CH3)2 and t-Bu is -C(CH3)3. In some embodiments, R1, R2, R4, and R5are H, and R3is pyrrole, alkyl (C1-C24), or fluoroalkyl (C1-C24).

[0019] As noted above, in formula (I), E1and E2may individually represent a moiety having a double or triple bond, or where E1and E2join together to form a cyclic structure with the Ni to which they are bound. Illustrative E1and E2include olefins, ketones, aldehydes, imines, and the like. E1and E2may join as a single group as an alkyne of formula R10C≡CR11, where R10and R11are individually H or alkyl. In some embodiments, E1and E2are joined together to form a substituted or unsubstituted diene, 6 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 such cycloocta-1,5-diene. In other embodiments, E1and E2together form a quinone, it may be one of formula:where each of R6, R7, R8, and R9is individually H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl, or R6and R7or R8and R9may fuse to form a fused ring structure that is substituted or unsubstituted. In some embodiments, E is cyclooctadiene and R1and R5are each (2,4,6-(i-Pr)3C6H2)2C6H3 or (2,4,6-(t-Bu)3C6H2)2C6H3, wherein i-Pr is -CH(CH3)2 and t-Bu is -C(CH3)3.

[0020] In some embodiments, the catalyst is Ni(COD)(CNArTripp2)2:As used herein, “Tripp” is an abbreviation for tri-isopropyl, and Mes is an abbreviation for mesityl or tri-tertiary butyl. In other embodiments, the catalyst is Ni(COD)(CNArMes*2)2: 7 4924-0985-8130.4Atty. Dkt. No.: 114198-3210.

[0021] In another aspect, a method is provided for making a catalyst of formula (I). The method of making the catalyst includes contacting (i) a Ni0compound of formula NiE1E2E3E4, where E1, E2, E3, and E4are, individually, a moiety having a double or triple bond, or where E1and E2and / or E3and E4join together to form a cyclic structure with the Ni to which they are bound, and (ii) an isocyanide of formula ArNC, where Ar is a substituted or unsubstituted aryl group, to obtain a crude product, and purifying the crude product to obtain an isolated product of formula (I). In some embodiments, Ar is a group of formula:.

[0022] Where Ar is a group of the above formula, the R1, R2, R3, R4, and R5groups may each be independently H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl, or any two adjacent groups may fuse to form a ring that is substituted or unsubstituted. In some embodiments, R1and R5are substituted aryl and R2, R3, and R4are each H. In further embodiments, R1and R5are each (2,4,6-(i-Pr)3C6H2)2C6H3or (2,4,6-(t- Bu)3C6H2)2C6H3, where i-Pr is -CH(CH3)2and t-Bu is -C(CH3)3. In some embodiments, R1, R2, R4, and R5are H, and R3is pyrrole, alkyl (C1-C24), or fluoroalkyl (C1-C24). In 8 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 some embodiments, the isocyanide is CN(2,6-(2,4,6-(CH(CH3)2)3C6H2)2C6H3) or 2,2'',4,4'',6,6''-hexa-tert-butyl-[1,1':3',1''-terphenyl]-2'-yl)(methylidyne)-λ4-azane.

[0023] As noted above, E1, E2, E3, and / or E4may individually represent a moiety having a double or triple bond, or where E1and E2and / or E3and E4join together to form a cyclic structure with the Ni to which they are bound. Illustrative E1, E2, E3, and E4include olefins, ketones, aldehydes, imines, and the like. E1and E2and / or E3and E4may join as a single group as an alkyne of formula R10C≡CR11, where R10and R11are individually H or alkyl. In some embodiments, E1and E2and / or E3and E4are joined together to form a substituted or unsubstituted diene, such cycloocta-1,5-diene. The compound of formula NiE1E2E3E4may be Ni(COD)2. In other embodiments, where E1and E2and / or E3and E4together form a quinone, it may be of formula:where each of R6, R7, R8, and R9is individually H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl, or R6and R7or R8and R9may fuse to form a fused ring structure that is substituted or unsubstituted.

[0024] The method includes contacting a Ni0compound of formula NiE1E2E3E4and an isocyanide of formula ArNC. In some embodiments, the contacting includes preparing a solution of the isocyanide in a first solvent, and adding the solution of the isocyanide to the Ni0compound either neat or in a solvent; or preparing a solution of the Ni0compound in a first solvent, and adding the solution of the Ni0compound to the isocyanide either neat or in a solvent. The first solvent may include an ether, and the ether may include tetrahydrofuran. In any embodiment, the contacting may be performed for about 2 hours to about 10 hours, such as for about 6 hours.

[0025] The method also includes purifying the crude product to obtain an isolated product of formula (I). In some embodiments, the purifying includes extracting the crude 9 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 product with a second solvent. The second solvent may include an ether, including where the second solvent may include ethyl ether. In some embodiments, the purifying may further include dissolving the crude product in a third solvent. The third solvent may include an ether or an alkyl cyanide. In some embodiments, the third solvent may include ethyl ether and acetonitrile. In some embodiments, the purifying may include storing the crude product at about -80 ⁰C to about 0 ⁰C, such as storing at about -40 ⁰C.

[0026] In another aspect, a process is provided for producing silanes, such as dimerized or trimerized (or higher) silanes from a monosilane using the catalysts described herein. For example, in some embodiments, the process is for producing a second silane by contacting a first silane of formula RSiH3 with any of the catalysts described herein. In formula RSiH3, R may be H, alkyl, aryl, OR’, or NR’2, where R’ is H or alkyl; and the second silane may be a dimer or higher order silane of the first silane. In some embodiments, the second silane is of formula RSiH2-H2SiR or (RSiH)(H2SiR)2.

[0027] In some embodiments, R may be a substituted or unsubstituted phenyl. In other embodiments, R may be phenyl.

[0028] In some embodiments, the contacting in the process includes preparing a stock solution of the catalyst in a solvent, and adding the stock solution to the first silane either neat or in a solvent. In other embodiments, the contacting in the process includes comprising preparing a stock solution of the catalyst in a solvent and adding the first silane either neat or in a solvent to the stock solution.

[0029] The solvent used in the process, according to some embodiments, may be an ether, an aromatic solvent, or a hydrocarbon solvent. Illustrative solvents include, but are not limited to, benzene, toluene, hexanes, pentanes, heptanes, tetrahydrofuran, and the like. In some embodiments, the solvent may be tetrahydrofuran. However, chlorinated solvents and nitro-substituted solvents may deactivate the catalyst.

[0030] After the contacting step in the process, an isocyanide agent, or CO may be added after the contacting to remove the catalyst from the second silane product(s). Illustrative isocyanide agents include, but are not limited to m-xylene NC(2,6- (CH3)2C6H3NC), t-BuNC, PhNC, MeNC, or (i-Pr)2NNC). The process may further include removing unreacted first silane. 10 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0031] As noted above, the processes are generally low temperature processes for the synthesis of higher order silanes. As an illustration, the process may be conducted at a temperature of about -100°C to about 200°C. This may include from about -40°C to about 100°C. In other embodiments, the temperate at which the process is conducted is from about -40°C to about 25°C.

[0032] The present invention, thus generally described, will be understood more readily by reference to the following examples, which are provided by way of illustration and are not intended to be limiting of the present invention. EXAMPLES

[0033] Example 1. Synthesis of Ni(COD)(CNArTripp2)2.

[0034] A solution of CNArTripp2(1.85 g, 3.65 mmol, 2 equivalents, 70 mL; ArTripp2= 2,6-(2,4,6-(i-Pr)3C6H2)2C6H3; i-Pr = CH(CH3)2) in tetrahydrofuran (“THF”) was added dropwise to a THF suspension of Ni(COD)2(0.500 g, 1.82 mmol, 30 mL; COD = 1,5- cyclooctadiene). An orange color was observed upon complete addition of the isocyanide. The reaction mixture was stirred for 6 hours before drying in vacuo. The resulting orange solid was extracted with Et2O (50 mL) and filtered through celite. Removal of the solvent in vacuo resulted in a red-orange oil that contained non-coordinated COD. To remove COD impurities, the oil was dissolved in Et2O (10 mL) and acetonitrile (“MeCN;” 10 mL) was added to the solution. Upon complete addition of MeCN, an orange precipitate began to form. The mixture was then stored at -40 ˚C for 16 hours to encourage precipitation of 11 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 Ni(COD)(CNArTripp2)2. Isolation of the orange solid by filtration and subsequent drying in vacuo produced pure Ni(COD)(CNArTripp2) (Yield: 1.657 g, 1.402 mmol, 77%).

[0035] 1H NMR (300 MHz, C6D6, 20⁰C): δ 7.22 (8H, s, TrippH), 6.97 (4H, d, Jp- PhH = 7.1 Hz, m-PhH), 6.89 (2H, t, Jm-PhH = 7.1 Hz, p-PhH), 3.67 (br, 4H COD- olefinic), 2.91 (12H, m, i-Pr-CH), 1.99 (8H, br, COD-aliphatic), 1.38 (24H, d, J = 6.9 Hz, i-Pr-CH3), 1.29 (24H, d, J = 6.9 Hz, i-Pr-CH3), and 1.21 (24H, d, J = 6.9 Hz, i-Pr-CH3).

[0036] 13C{1H} NMR (500 MHz, C6D6, 20⁰C): 179.5 (C≡N), 149.1, 147.2, 137.8, 134.9, 131.6, 131.1, 125.6, 121.5, 90.0 (COD-olefinic), 35.3 (COD-aliphatic), 31.5, 31.0, 25.3, 24.8, and 24.4.

[0037] FTIR (C6D6, KBr plates): (νCN) = 2057(s), 2018(m), 1968(vs) cm-1; also 2959, 2923, 2865, 2826, 1605, 1566, 1466, 1410, 1394, 1338, 1319 cm-1.

[0038] Example 2. Synthesis of CNArMes*2((2,2'',4,4'',6,6''-hexa-tert-butyl- [1,1':3',1''-terphenyl]-2'-yl)(methylidyne)-^4-azane).

[0039] was prepared according to Org. Lett.2017, 19, 2607–2609. The primary organic impurity at this stage was HArMes*2, which can be removed using the following procedure.

[0040] Removal of HArMes*2. A 125 mL flat-bottomed flask was charged with a m-terphenyl mixture, n-pentane (40 mL), and a stir bar. Methylsulfonic acid (4 mL) was added dropwise to the vigorously stirred flask. [CH3SO3][H3NArMes*2] precipitated out as a yellow-brown oil. The pentane layer was decanted, and the oil was washed with n- 12 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 pentane (3 x 20 mL) to remove HArMes*2. The remaining oil was solubilized in Et2O (40 mL). A solution of NaOH (10 M) was added dropwise until the aqueous layer had a basic pH (>10). The organic and aqueous layers were separated, and the aqueous layer was back-extracted with Et2O (40 mL). The solvent was removed on a rotary evaporator, and the resulting residue was recrystallized from EtOH.

[0041] Preparation of H(O)CNHArMes*2. A 20 mL scintillation vial was charged with neat acetic anhydride (25.5 mL, 269 mmol, 40 equiv.) and stir bar. Formic acid (10.2 mL, 269 mmol, 40 equiv.) was added dropwise to the rapidly stirred acetic anhydride over the course of 5 minutes. Formyl acetic anhydride was then formed over the course of an hour at 40 ˚C. H2NArMes*2(3.92 g, 6.73 mmol) was solubilized in dry THF (100 mL) and transferred to a 250 mL Schlenk flask in the box. The flask was sealed with a septum and removed from the box before placing under positive nitrogen pressure. The formyl acetic anhydride was then transferred to the Schlenk flask via cannula. The reaction mixture was heated to 65 ˚C for four days. After cooling to room temperature, the reaction was concentrated on a rotary evaporator to produce a light-yellow solid. The solid was suspended in a 1:1 water / EtOH mixture (50 mL) to remove excess acetic acid. H(O)CNHArMes*2was then isolated as an off-white solid by vacuum filtration (Yield: 3.27 g, 5.36 mmol, 80%).

[0042] 1H NMR: (402 MHz, C6D6, 20⁰C): δ 7.82 (1H, d, JNH = 10.9 Hz, H(O)C), 7.74 (4H, s, Mes*H), 7.28 (2H, d, Jp-PhH = 7.6 Hz, m-PhH), 7.00 (1H, JH(O)C = 10.9 Hz, NH), 6.60 (1H, t, Jm-PhH = 7.6 Hz, p-PhH), 1.32 (36H, s, o-t-Bu), and 1.30 (18H, s, p-t- Bu).

[0043] 13C NMR: (500 MHz, C6D6, 20⁰C): δ 161.4 (aldehyde), 150.0, 148.9, 138.1, 137.8, 133.9, 131.0, 124.7, 118.54, 38.8, 35.0, 34.4, and 31.4.

[0044] Preparation of CNArMes*2: A 100 mL RB flask was charged with H(O)CNHArMes*2(3.27 g, 5.36 mmol), dichloromethane (“DCM;” 100 mL), and a stir bar. Diisopropylamine (7.3 mL, 53.6 mmol, 10 equiv.) was subsequently added to the flask and allowed to stir for 10 minutes. OPCl3(2.5 mL, 26.8 mmol, 5 equiv.) was then added to the reaction which was subsequently sealed with a septum and removed from the box. After 16 hours, water was added to the flask to quench the remaining OPCl3. The organic and aqueous layers were separated, and the aqueous layer was back-extracted with DCM (3 x 13 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 20 mL). The organic fractions were combined, dried with MgSO4, and filtered. The filtrate was then concentrated on a rotary evaporator to produce a yellow solid. Sonication of the solid in cold MeCN and subsequent filtration produced a white solid (Yield: 2.90 g, 4.90 mmol, 91%).

[0045] 1H NMR: (500 MHz, C6D6, 20⁰C): δ 7.75 (4H, s, Mes*H), 7.26 (2H, d, Jp- PhH = 7.8 Hz, m-PhH), 6.64 (1H, t, Jm-PhH = 7.8 Hz, p-PhH), 1.35 (36H, s, o-t-Bu), and 1.33 (18H, s, p-t-Bu).

[0046] 13C NMR: (500 MHz, C6D6, 20⁰C): δ 172.7 (C☰N), 149.4, 148.5, 142.0, 137.0, 132.8, 124.1, 123.9, 38.8, 35.0, 34.9, and 31.4.

[0047] FTIR (C6D6, KBr plates): (νC☰N) = 2115(s) cm-1; also 2964, 2907, 2871, 1604, 1477, 1396, 1364, 1240, 1215, 881, 812, and 769 cm-1.

[0048] Example 3. Synthesis of Ni(COD)(CNArMes*2)2.

[0049] Ni(COD)(CNArMes*2)2was prepared analogous to Ni(COD)(CNArTripp2)2. A THF solution of CNArMes*2(0.300 g, 0.51 mmol, 2 equiv, 3 mL) was added dropwise to a THF suspension of Ni(COD)2 (0.070 g, 0.25 mmol, 3 mL). A cherry-red color was observed upon complete addition of the isocyanide. The reaction mixture was stirred for 6 hours prior to drying in vacuo. The resulting red-orange oil was extracted with Et2O (10 mL) and filtered through celite. Removal of the solvent in vacuo resulted in a red-orange oil that contained non-coordinated COD. To remove COD impurities, the oil was dissolved in Et2O (3 mL) and MeCN (3 mL) was added to the solution. Upon complete addition of MeCN, an orange precipitate began to form. The mixture was stored at -40⁰C 14 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 for 16 hours to further encourage precipitation of Ni(COD)(CNArMes*2)2. Isolation of the orange solid by filtration and subsequent drying in vacuo produced pure Ni(COD)(CNArMes*2)2 (Yield: 0.330 g, 0.24 mmol, 98%).

[0050] 1H NMR (300 MHz, C6D6, 20⁰C): δ 7.72 (8H, s, Mes*H), 7.20 (4H, d, Jp- PhH = 7.8 Hz, m-PhH), 6.60 (2H, Jm-PhH = 7.8 Hz, t, p-PhH), 3.77 (4H, br, COD- olefinic), 1.92 (8H, br, COD-aliphatic), 1.47 (36H, s, p-t-Bu), and 1.39 (72H, s, o-t-Bu).

[0051] 13C{1H} NMR (500 MHz, C6D6, 20⁰C): 179.2 (C≡N), 148.9, 148.5, 140.4, 137.3, 134.9, 134.1, 123.5, 121.1, 89.7 (COD-olefenic), 38.6, 35.1, 35.0, 31.8, and 30.7.

[0052] FTIR (C6D6, KBr plates): (νCN) = 2056(s), 2011(sh), and 1974(vs) cm-1; also 2963, 2907, 2871, 2813, 1604, 1568, 1477, 1394, 1363, 1240, 1215, 1070, 879, and 812 cm-1.

[0053] Example 4. Phenylsilane Dehydrocoupling.

[0054] Selective PhSiH3 dehydrocoupling may be promoted through the addition of Ni(COD)(CNArMes*2)2or Ni(COD)(CNArTripp2)2at temperatures as low as -40⁰C. Selectivity for the dimer and trimer may be achieved through cooling the reaction down to -40⁰C, although the turnover rate of the catalyst is somewhat suppressed at these lower temperatures. Alternatively, a nearly complete selectivity for dimer formation may be achieved through ultra-low catalyst loadings of Ni(COD)(CNArMes*2)2(0.001 mol% relative to PhSiH3). The catalytic activity may be quenched through the addition of m- XyNC (minimum of 4 equivalents relative to catalyst; m-XyNC = 2,6-(CH3)2C6H3NC) to form the inactive species, Ni(m-XyNC)4. If the Ni(m-XyNC)4is not removed prior to separation of the monomer / dimer / trimer / oligomer mixture, an active species will form at temperatures greater than 60⁰C, leading to dehydrocoupling and rearrangement. 15 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0055] Example 5. PhSiH3(Monomer) Characterization.1H NMR (402 MHz, C6D6, 20⁰C): δ 7.39-7.37 (2H, m), 7.14-7.05 (3H, m), and 4.23 (3H, s, JSi-H = 199.9 Hz, - SiH3).29Si{1H} NMR (402 MHz, C6D6, 20⁰C): δ -59.7.

[0056] Example 6. (PhH2Si)2 (Dimer) Characterization.1H NMR (402 MHz, C6D6, 20⁰C): δ 7.45-7.43 (4H, m), 7.10-7.02 (6H, m), and 4.50 (4H, s, JSi-H =193.0 Hz, JSi29-H,H = 2.8 Hz).29Si{1H} NMR (402 MHz, C6D6, 20⁰C): δ -61.2

[0057] Example 7. (PhSiH)(PhSiH2)2 (Trimer) Characterization.1H NMR (402 MHz, C6D6, 20⁰C): δ 4.61 (4H, d, Si-H terminal), and 4.59 (1H, quint, Si-H internal). Note: aryl protons are not yet assigned.29Si{1H} NMR (402 MHz, C6D6, 20⁰C): δ -58.6 (terminal) and -68.1 (internal).

[0058] Example 8. (PhSiH)2(PhSiH2)2(linear tetramers, meso- and racemo-) Characterization.1H NMR (402 MHz, C6D6, 20⁰C): δ 4.63 (6H, m, Si-H internal and terminal for both diads). Note: aryl protons are not yet assigned.29Si{1H} NMR (402 MHz, C6D6, 20⁰C): δ -58.5 (terminal, meso- or racemo-), -58.6 (terminal, meso- or racemo-), -64.6 (internal, meso- or racemo-), and -65.2 (internal, meso- or racemo-).

[0059] Example 9. (PhSi)(PhSiH2)3(Branched Tetramer) Characterization.1H NMR (402 MHz, C6D6, 20⁰C): δ 4.73 (6H, s, Si-H). Note: aryl protons are not yet assigned.29Si{1H} NMR (402 MHz, C6D6, 20⁰C): δ -56.0 (terminal) and -83.1 (internal).

[0060] Example 10.1H NMR Estimation of PhSiH3 Conversion. At short reaction times, only monomer, dimer and trimer could be detected by GCMS. Relative 16 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 integration of the monomer / dimer / trimer Si-H chemical shifts in the 1H NMR spectra can be used to estimate the extent of monomer conversion and yield of dimer / trimer. The amount of trimer in the system is likely overestimated due to a large T2 (spin-spin relaxation constant) broadening the trimer Si-H chemical shift.^ SMonomer = Relative integration of monomer signal at 4.23 ppm in the1H NMR spectrum. ^ SDimer = Relative integration of dimer signal at 4.50 ppm in the1H NMR spectrum. ^ STrimer = Relative integration of trimer signal at 4.62 ppm in the1H NMR spectrum.

[0061] Example 11. Cold Synthesis of (PhH2Si)2using Ni(COD)(CNArMes*2)2. A precatalyst stock solution of Ni(COD)(CNArMes*2)2 was prepared in THF (0.005 g Ni(COD)(CNArMes*2)2 per mL THF). The stock solution (0.05 mL; 0.00025 g Ni(COD)(CNArMes*2)2, 0.01 mol%) was dispensed into a 20 mL scintillation vial and dried in vacuo. The vial containing the precatalyst and a vial containing PhSiH3 (0.200 g, 1.84 mmol) were precooled to -40⁰C. Upon combination of PhSiH3 with the precatalyst, there was an observable effervescence of hydrogen gas. After 30 minutes, approximately 37.3% of the starting PhSiH3had been converted to provide a 31.5% yield of dimer and a 5.8% yield of trimer, as determined via1H NMR. At longer reaction times, accumulation of higher “n” oligosilanes could be observed via1H NMR. Catalyst activity was quenched through the addition of m-XyNC (0.0097 g, 0.0184 mmol, 4 mol%). 17 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0062] Example 12. Cold Synthesis of (PhH2Si)2using Ni(COD)(CNArTripp2)2. A precatalyst stock solution of Ni(COD)(CNArTripp2)2was prepared in THF (0.022 g Ni(COD)(CNArTripp2)2 per mL THF). 0.2 mL of the precatalyst stock (0.0044 g Ni(COD)(CNArTripp2)2, 0.2 mol%) was dispensed into a 20 mL scintillation vial and dried in vacuo. The vial containing the precatalyst and a vial containing and PhSiH3(0.200 g, 1.84 mmol) were precooled to -40⁰C. Upon combination of PhSiH3 with the nickel precatalyst, there was an observable effervescence of hydrogen gas. After 30 minutes, approximately 25% of the starting PhSiH3had been converted to give a 23.6 % yield of dimer and a 1.3% yield of trimer, as determined via1H NMR. At longer reaction times, accumulation of higher “n” oligosilanes could be observed via1H NMR. Catalyst activity was quenched through the addition of m-XyNC (0.0097 g, 0.0184 mmol, 4 mol%).

[0063] Example 13. Low Catalyst Loading for Synthesis of (PhH2Si)2. A primary stock solution was made using Ni(COD)(CNArMes*2)2 (0.075 g, 0.0056 mmol) and THF (10 mL THF, 0.0075 g of Ni(COD)(CNArMes*2)2 / mL THF). A secondary stock was made using 1 mL of the primary stock and diluting it with an additional 4 mL of THF (5 mL total volume, 0.0015 g Ni(COD)(CNArMes*2)2 / mL THF). 0.5 mL of the secondary stock was dispensed (0.00075 g Ni(COD)(CNArMes*2)2 , 0.00055 mmol, 0.001 mol%) and dried in vacuo. PhSiH3(6.000 g, 55.44 mmol) was added to the vial containing the nickel precatalyst to produce a light orange solution that vigorously bubbled. A stir bar was added to the reaction mixture to help promote efficient release of hydrogen gas produced by the dehydrocoupling reaction. After 20 minutes, m-XyNC (15 mg, 0.11 mmol, 0.2 mol%) was added, which produced a bright yellow solution that did not effervesce. Approximately 26.3% of the starting PhSiH3 had been converted to give a 19.3 % yield of dimer and a 7.0% yield of trimer, as determined by1H NMR.

[0064] Example 14. Separation of PhSiH3, (PhH2Si)2, and (PhSiH)(PhSiH2)2. After addition of m-XyNC to a dehydrocoupling reaction, the following workup procedure is proposed for isolation of the dimer / trimer and recovery of the unconverted monomer. Near quantitative recovery of unconverted PhSiH3can be achieved via vacuum distillation of the reaction mixture at room temperature with a receiving flask cooled by liquid nitrogen. The mixture of dimer and trimer can be separated from CNArMes*2and Ni(m- XyNC)4via column chromatography on SiO2with pentane as the eluent. (Note: If the proposed solution is unable to successfully remove the Ni species from the dimer / trimer, 18 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 SiO2loaded with 4-isocyanobenzoic acid may help facilitate removal of the remaining Ni. Separation of dimer from trimer can be achieved via vacuum distillation at 100⁰C.

[0065] While certain embodiments have been illustrated and described, it should be understood that changes and modifications can be made therein in accordance with ordinary skill in the art without departing from the technology in its broader aspects as defined in the following claims.

[0066] The embodiments, illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising,” “including,” “containing,” etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. Additionally, the phrase “consisting essentially of” will be understood to include those elements specifically recited and those additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase “consisting of” excludes any element not specified.

[0067] The present disclosure is not to be limited in terms of the particular embodiments described in this application. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and compositions within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions, or biological systems, which can of course vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. 19 4924-0985-8130.4Atty. Dkt. No.: 114198-3210

[0068] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0069] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” and the like, include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member.

[0070] All publications, patent applications, issued patents, and other documents referred to in this specification are herein incorporated by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. Definitions that are contained in text incorporated by reference are excluded to the extent that they contradict definitions in this disclosure.

[0071] Other embodiments are set forth in the following claims. 20 4924-0985-8130.4

Claims

Atty. Dkt. No.: 114198-3210 WHAT IS CLAIMED IS:

1. A catalyst of formula (I):Ar is a substituted or unsubstituted aryl group; and E1and E2are, individually, a moiety having a double or triple bond, or where E1and E2join together to form a cyclic structure with the Ni to which they are bound.

2. The catalyst of claim 1, wherein Ar is a phenyl group of formula:, wherein R1, R2, R3, R4, and R5groups may each be independently H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl, or any two adjacent groups may fuse to form a ring that is substituted or unsubstituted.

3. The catalyst of claim 2, wherein R1and R5are substituted aryl and R2, R3, and R4are each H.

4. The catalyst of claim 3, wherein R1and R5are each (2,4,6-(i-Pr)3C6H2)2C6H3 or (2,4,6- (t-Bu)3C6H2)2C6H3, wherein i-Pr is -CH(CH3)2 and t-Bu is -C(CH3)3. 21 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 5. The catalyst of claim 2, wherein R1, R2, R4, and R5are H, and R3is pyrrole, alkyl (C1- C24), or fluoroalkyl (C1-C24).

6. The catalyst of any one of claims 1-5, wherein E1and E2are individually an olefin, ketone, aldehyde, or imine.

7. The catalyst of any one of claims 1-5, wherein E1and E2join as a single group as an alkyne of formula R10C≡CR11, where R10and R11are individually H or alkyl.

8. The catalyst of any one of claims 1-5, wherein E1and E2together are a substituted or unsubstituted cycloocta-1,5-diene.

9. The catalyst of any one of claims 1-5, wherein E1and E2together are a cyclooctadiene and R1and R5are each (2,4,6-(i-Pr)3C6H2)2C6H3 or (2,4,6-(t-Bu)3C6H2)2C6H3, wherein i-Pr is -CH(CH3)2and t-Bu is -C(CH3)3.

10. The catalyst of any one of claims 1-5, wherein E1and E2together are a quinone of formula, wherein: each of R6, R7, R8, and R9is individually H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl; or R6and R7or R8and R9fuse to form a fused ring structure that is substituted or unsubstituted. 22 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 11. The catalyst of claim 1 which is Ni(COD)(CNArTripp2)212. The catalyst of claim 1 which is Ni(COD)(CNArMes*2)2.

13. A process for producing a second silane, the process comprising: contacting a first silane of formula RSiH3with the catalyst of any one of claims 1- 8; wherein: R is H, alkyl, or aryl; and the second silane is a dimer or higher order silane of the first silane.

14. The process of claim 13, wherein the second silane is of formula RSiH2-H2SiR or (RSiH)(H2SiR)2.

15. The process of claim 13 or 14, wherein R is a substituted or unsubstituted phenyl. 23 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 16. The process of any one of claims 13-15, wherein R is phenyl.

17. The process of any one of claims 13-16, wherein the contacting comprises preparing a stock solution of the catalyst in a solvent, and adding the stock solution to the first silane either neat or in a solvent.

18. The process of any one of claims 13-16, wherein the contacting comprising preparing a stock solution of the catalyst in a solvent and adding the first silane either neat or in a solvent to the stock solution.

19. The process of any one of claims 17 or 18, wherein the solvent is an ether.

20. The process of claim 19, wherein the ether is tetrahydrofuran.

21. The process of any one of claims 13-20, wherein m-xyleneNC (2,6-(CH3)2C6H3NC) is added after the contacting.

22. The process of any one of claims 13-21 further comprising removing unreacted first silane.

23. The process of any one of claims 13-22 that is conducted at a temperature of about -40°C to about 100°C.

24. The process of any one of claims 13-23 that is conducted at a temperature of about -40°C to about 25°C.

25. (2,2'',4,4'',6,6''-hexa-tert-butyl-[1,1':3',1''-terphenyl]-2'-yl)(methylidyne)-^4-azane.

26. A method of making the catalyst of any one of claims 1-12 comprising: contacting (i) a Ni0compound of formula NiE1E2E3E4, where E1, E2, E3, and E4are, individually, a moiety having a double or triple bond, or where E1and E2and / or E3and E4join together to form a cyclic structure with the Ni to which they are bound, and (ii) an isocyanide of formula ArNC, where Ar is a substituted or unsubstituted aryl group, to obtain a crude product; and 24 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 purifying the crude product to obtain an isolated product of formula (I).

27. The method of claim 26, wherein Ar is a phenyl group of formula:, wherein R1, R2, R3, R4, and R5groups may each be independently H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl, or any two adjacent groups may fuse to form a ring that is substituted or unsubstituted.

28. The method of claim 26 or claim 27, wherein R1and R5are substituted aryl and R2, R3, and R4are each H.

29. The method of any one of claims 26-28, wherein R1and R5are each (2,4,6-(i- Pr)3C6H2)2C6H3or (2,4,6-(t-Bu)3C6H2)2C6H3, wherein i-Pr is -CH(CH3)2and t-Bu is -C(CH3)3.

30. The method of any one of claims 26-29, wherein R1, R2, R4, and R5are H, and R3is pyrrole, alkyl (C1-C24), or fluoroalkyl (C1-C24).

31. The method of any one of claims 26-30, wherein the isocyanide is CN(2,6-(2,4,6- (CH(CH3)2)3C6H2)2C6H3) or 2,2'',4,4'',6,6''-hexa-tert-butyl-[1,1':3',1''-terphenyl]-2'- yl)(methylidyne)-^4-azane.

32. The method of any one of claims 26-31, wherein E1, E2, E3, and E4are individually an olefin, ketone, aldehyde, or imine. 25 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 33. The method of any one of claims 26-32, wherein E1and E2and / or E3and E4join as a single group as an alkyne of formula R10C≡CR11, where R10and R11are individually H or alkyl.

34. The method of any one of claims 26-32, wherein E1and E2together and / or E3and E4together are a substituted or unsubstituted cycloocta-1,5-diene.

35. The method of any one of claims 26-32, wherein the compound of formula NiE1E2E3E4is Ni(COD)2.

36. The method of any one of claims 26-32, wherein E1and E2and / or E3and E4together are a quinone of formula, wherein: each of R6, R7, R8, and R9is individually H, F, Cl, Br, I, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkaryl; or R6and R7or R8and R9fuse to form a fused ring structure that is substituted or unsubstituted.

37. The method of any one of claims 26-36, wherein the contacting comprises (i) preparing a solution of the isocyanide in a first solvent, and adding the solution of the isocyanide to the Ni0compound either neat or in a solvent; or (ii) preparing a solution of the Ni0compound in a first solvent, and adding the solution of the Ni0compound to the isocyanide either neat or in a solvent.

38. The method claim 37, wherein the first solvent comprises an ether.

39. The method of claim 38, wherein the ether comprises tetrahydrofuran. 26 4924-0985-8130.4Atty. Dkt. No.: 114198-3210 40. The method of any one of claims 27-39, wherein the contacting is performed for about 2 hours to about 10 hours.

41. The method of any one of claims 27-40, wherein the purifying comprises extracting the crude product with a second solvent.

42. The method of claim 41, wherein the second solvent comprises an ether.

43. The method of claim 42, wherein the second solvent comprises ethyl ether.

44. The method of any one of claims 41-44, wherein the purifying further comprises dissolving the crude product in a third solvent.

45. The method of claim 44, wherein the third solvent comprises an ether or an alkyl cyanide.

46. The method of claim 44, wherein the third solvent comprises ethyl ether and acetonitrile.

47. The method of any one of claims 40-46, wherein the purifying further comprises storing the crude product at about -80 ⁰C to about 0 ⁰C. 27 4924-0985-8130.4

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