Monoalkyltin compounds with low polyalkyl contamination, compositions thereof and methods

Abstract

To provide a method to produce a monoalkyl tin trialkoxide.SOLUTION: A method to form a monoalkyl tin trialkoxide includes the step for reacting a monoalkyl triamido tin compound (RSn(NR'''COR'')3) with an alkali alkoxide compound (QOR', where Q is an alkali metal atom) in an organic solvent to form a product compound represented by the chemical formula RSn(OR') 3, wherein R is a hydrocarbyl group with 1-31 carbon atoms and wherein R', R'' and R''' are independently a hydrocarbyl group with 1-10 carbons.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of pending U.S. patent application Ser. No. 15 / 950,292, filed April 11, 2018, to Edson et al., "Monoalkyl Tin Compounds With Low Polyalkyl Contamination, Their Compositions and Methods," and a continuation-in-part of pending U.S. patent application Ser. No. 15 / 950,286, filed April 11, 2018, to Edson et al., "Monoalkyl Tin Compounds With Low Polyalkyl Contamination, Their Compositions and Methods," both of which are incorporated herein by reference.

[0002] The present invention relates to high purity compositions of monoalkyltin triamides, monoalkyltin trialkoxides, or monoalkyltin triamides, and methods for producing them. [Background technology]

[0003] Organometallic compounds have attracted interest for providing metal ions in solution-processable forms. Alkyltin compounds provide radiation-sensitive Sn-C bonds that can be used to pattern structures lithographically. The processing of semiconductor materials with ever-decreasing dimensions has led to a demand for more versatile materials to achieve the desired patterning resolution, and alkyltin compounds are promising advanced materials that offer patterning advantages. Summary of the Invention [Means for solving the problem]

[0004] In a first aspect, the present invention relates to a composition comprising a monoalkyltin trialkoxide compound represented by the formula RSn(OR')3 or a monoalkyltin triamide compound represented by the formula RSn(NR'2)3, where R is a hydrocarbyl group having 1 to 31 carbon atoms and R' is a hydrocarbyl group having 1 to 10 carbon atoms, and up to 4 mole percent of a dialkyltin compound, based on the total amount of tin. The monoalkyltin triamide can be reacted with an alcohol represented by the formula HOR" in an organic solvent to form RSnOR"3, where R" is independently a hydrocarbyl group having 1 to 10 carbon atoms, to form a product composition having up to 4 mole percent of a dialkyltin compound, based on the total amount of tin.

[0005] In a further aspect, the present invention relates to a composition comprising a monoalkyltriamidotin compound represented by the formula RSn-(NR'COR'')3, where R is a hydrocarbyl group having 1 to 31 carbon atoms, and R' and R'' are independently hydrocarbyl groups having 1 to 10 carbon atoms.

[0006] In another aspect, the present invention relates to a method for forming a monoalkyltin triamide compound, the method comprising reacting an alkylating agent selected from the group consisting of RMgX, RZn, RZnNR', or combinations thereof with Sn(NR') in a solution comprising an organic solvent, wherein R is a hydrocarbyl group having 1 to 31 carbon atoms, X is a halogen, and R' is a hydrocarbyl group having 1 to 10 carbon atoms.

[0007] In another aspect, the invention relates to a process for selectively forming monoalkyltin trialkoxide compounds with low contamination of dialkyltins, comprising the step of reacting RSn(NR'2)3 with an alcohol represented by the formula HOR" in an organic solvent to form RSnOR"3, wherein the RSn(NR'2)3 reactant has about 4 mole % or less of dialkyltin contamination and is the product of the process of claim 17, wherein R is a hydrocarbyl group having 1 to 31 carbon atoms, and R' and R" are independently hydrocarbyl groups having 1 to 10 carbon atoms.

[0008] In yet another aspect, the present invention relates to a method for forming monoalkyltin triamides, the method comprising the steps of reacting a monoalkyltin triamide compound represented by the formula RSn(NR'2)3 with an amide (R"CONHR'") in an organic solvent, where R is a hydrocarbyl group having 1 to 31 carbon atoms, and R', R" and R'" are independently hydrocarbyls having 1 to 8 carbon atoms, and collecting a solid product represented by the formula RSn(NR'"COR").

[0009] Additionally, the present invention relates to a method for forming a monoalkyltin trialkoxide, the method comprising the step of reacting a monoalkyltriamidotin compound (RSn(NR'''COR'')3) with an alkali alkoxide compound (QOR', where Q is an alkali metal atom) in an organic solvent to form a product compound represented by the chemical formula RSn(OR')3, where R is a hydrocarbyl group having 1 to 31 carbon atoms, and R', R'', and R''' are independently hydrocarbyl groups having 1 to 10 carbons.

[0010] Additionally, the present invention relates to a method for purifying monoalkyltin trialkoxide, comprising the step of distilling a blend of monoalkyltin trialkoxide and a tetradentate non-planar complexing agent. [Brief explanation of the drawings]

[0011] [Figure 1] This is the 1H NMR spectrum of t-BuSn(NMe2)3 synthesized using a Grignard reagent. [Figure 2] 1 is a 119Sn NMR spectrum of t-BuSn(NMe2)3, which is used correspondingly to obtain the spectrum of FIG. [Figure 3] 1H NMR spectrum of CySn(NMe2)3 (Cy = cyclohexyl) synthesized using alkylzinc halide reagents. [Figure 4] 119Sn NMR spectrum of CySn(NMe2)3, which is used correspondingly to obtain the spectrum of FIG. 3. [Figure 5] 1H NMR spectrum of CyHpSn(NMe2)3 synthesized using a dialkylzinc reagent. [Figure 6] 119Sn NMR spectrum of CyHpSn(NMe2)3, correspondingly used to obtain the spectrum of FIG. 5. [Figure 7] This is a 1H NMR spectrum of t-BuSn(NMe2)3 synthesized using a Grignard reagent and a neutral base. [Figure 8] 119Sn NMR spectrum of t-BuSn(NMe2)3, correspondingly used to obtain the spectrum of FIG. 7. [Figure 9] This is the 1H NMR spectrum of t-BuSn(Ot-Am)3 synthesized from t-BuSn(NMe2)3. [Figure 10] 10 is a 119Sn NMR spectrum of t-BuSn(Ot-Am)3, which is used correspondingly to obtain the spectrum of FIG. [Figure 11] The structure of t-butyltris(N-methylacetamido)tin(IV) obtained by X-ray structure determination of the crystalline product. [Figure 12] 1H NMR spectrum of t-butyltris(N-methylacetamido)tin(IV). [Figure 13]This is the 119Sn NMR spectrum of t-butyltris(N-methylacetamido)tin(IV). [Figure 14] This is the 1H NMR spectrum of t-BuSn(Ot-Am)3 synthesized from t-butyltris(N-methylacetamido)tin(IV). [Figure 15] This is the 119Sn NMR spectrum of t-BuSn(Ot-Am)3 synthesized from t-butyltris(N-methylacetamido)tin(IV). [Figure 16] 119Sn NMR spectrum of t-BuSn(NMe2)3 with t-Bu2Sn(NMe2)2 added. The signal at 85.48 ppm corresponds to t-BuSn(NMe2)3, and the signal at 56.07 ppm corresponds to (t-Bu)2Sn(NMe2)2. [Figure 17] 17 is a 119Sn NMR spectrum of t-BuSn(NMe2)3 from the first fraction collected by fractional distillation of the sample of FIG. 16. [Figure 18] 17 is a 119Sn NMR spectrum of t-BuSn(NMe2)3 from the second fraction collected by fractional distillation of the sample of FIG. 16. [Figure 19] 17 is a 119Sn NMR spectrum of t-BuSn(NMe2)3 from the third fraction collected by fractional distillation of the sample of FIG. 16. [Figure 20] 119Sn NMR spectrum of baseline tBuSn(OtAm)3. [Figure 21] 119Sn spectrum of redistilled tBuSn(OtAm)3 after addition of tris(2-aminoethyl)amine (TREN). DETAILED DESCRIPTION OF THE INVENTION

[0012] Methods have been discovered for obtaining monoalkyltin compositions, particularly monoalkyltin triamides, monoalkyltin trialkoxides, and monoalkyltrimidotins, that are low in polyalkyltin by-products. In particular, three methods have been developed for synthesizing monoalkyltin triamides that are relatively low in polyalkyltin by-products, which can be used as synthesized or further purified. In this case, selectively synthesized monoalkyltin triamides can be used to synthesize monoalkyltin trialkoxides that are correspondingly low in polyalkyltin by-products. Furthermore, whether highly pure or not, monoalkyltin triamides can be reacted in solution to form solid monoalkyltin triamides that are free of polyalkyl by-products in the crystals, and this method has been found to be effective for forming monoalkyltin triamides that are low in polyalkyl by-products. The synthesized monoalkyltin amides and monoalkyltin alkoxides can be further purified by fractional distillation to effectively reduce polyalkyl contaminants beyond the levels that may already be relatively low from direct synthesis. Analytical techniques can be used to determine the level of contaminants. In some embodiments, quantitative NMR (qNMR) indicates that the by-products can be reduced to concentrations of less than 1 mole percent. The product tin compositions can be useful as precursors for the synthesis of desirable patterning materials. For use as precursors to patterning materials, the reduction of polyalkyltin by-products can be beneficial for the properties of monoalkyltin product compositions for use as EUV and UV photoresists or electron beam patterning resists.

[0013] Monoalkyltin triamides can be useful intermediates in the preparation of organotin photoresists. Methods for preparing monoalkyltin triamides have long used lithium reagents to convert tin tetraamides to the desired triamides. For example, t-butyltris(diethylamido)tin (t-BuSn(NEt2)3) can be synthesized using lithium reagents according to the method of Haenssgen, D.; Puff, H.; Beckerman, N.J. Organomet. Chem. 1985, 293, 191 (incorporated herein by reference). However, these methods using lithium reagents can produce mixtures of monoalkyl and dialkyltin products. Furthermore, lithium contamination can be undesirable for semiconductor applications. Reported methods for preparing monoalkyltin triamides containing secondary alkyl groups produce mixtures enriched in mono-, di-, and triakyltin products. As discussed below, it may be desirable to reduce any polyalkyl by-products, such as dialkyltin contaminants. Although mono- and di-alkyl species can be separated from one another for some compounds, this separation or purification process generally adds to production costs, and entrained di-alkyl impurities can impair the performance of downstream photoresist products. Thus, it may be desirable to synthesize mono-alkyl tin compounds with higher purity, so that any subsequent purification, if necessary, using, for example, fractional distillation, further reduces di- or poly-alkyl contamination. If the as-synthesized composition is of sufficiently high purity, further purification by fractional distillation can be avoided.

[0014] The use of high-purity monoalkyltin compounds, particularly mercapto compounds, as polymer stabilizers is described in U.S. Pat. No. 8,198,352 to Deelman et al., entitled "High Purity Monoalkyltin Compounds and Uses Thereof," and U.S. Pat. No. 9,745,450 to Frenkel et al., entitled "Stabilizers Containing High Purity Mono-Alkyltin Compounds," both of which are incorporated herein by reference. These patents describe the formation of high-purity monoalkyl halides as precursors for the synthesis of stabilizer compounds. The process described herein focuses on the synthesis of high-purity monoalkyltin triamide, monoalkyltin trialkoxide, or monoalkyltriamide tin compounds using a different and efficient synthesis method that can be used in conjunction with fractional distillation for purification.

[0015] The use of alkylmetal coordination compounds in high performance radiation-based patterning compositions is described, for example, in U.S. Pat. No. 9,310,684 to Meyers et al., entitled "Organometallic Solution Based High Resolution Patterning Compositions," which is incorporated herein by reference. Improvements to these organometallic compositions for patterning are described in U.S. Patent Application Publication No. 2016 / 0116839 A1 to Meyers et al., entitled "Organometallic Solution Based High Resolution Patterning Compositions and Corresponding Methods," and U.S. Patent Application Publication No. 2017 / 0102612 A1 to Meyers et al., entitled "Organotin Oxide Hydroxide Patterning Compositions, Precursors, and Patterning" (hereinafter "Publication No. '612"), both of which are incorporated herein by reference.

[0016] Radiation patterning performed using alkyltin compositions is generally performed using alkyltin oxo-hydroxy moieties. The compositions synthesized herein can be effective precursors for forming alkyltin oxo-hydroxy compositions that are effective for high resolution patterning. The alkyltin precursor compositions are hydrolyzed with water or other suitable reagents under appropriate conditions to form a group that can be represented by the formula RSnO (1.5-(x / 2)) (OH) x (where 0 < x ≦ 3) to form an alkyltin oxo-hydroxy patterning composition. The hydrolysis and condensation reactions that can vary the composition with the hydrolysis group (X) are shown in the following reactions: RSnX3 + 3H2O → RSn(OH)3 + 3HX, RSn(OH)3 → RSnO (1.5-(x / 2)) OH x + (x / 2)H2O.

[0017] When the hydrolysis product HX is sufficiently volatile, in situ hydrolysis can be performed using water vapor during the support coating process, but the hydrolysis reaction can also be performed in solution to form an alkyltin oxo-hydroxy composition. These processing options are further described in Application Publication No. ’612.

[0018] Polyalkyltin impurity compositions can affect condensation, resulting in outgassing of photoresists during lithographic processing, which increases the likelihood of tin contamination of equipment used for thin film deposition and patterning. Based on these concerns, reducing or eliminating dialkyl or other polyalkyl components is highly desirable. Three types of compositions are suitable for the processes described herein to reduce polyalkyltin contaminants in the final resist composition: monoalkyltin triamides, monoalkyltin trialkoxides, and monoalkyltin triamides. As further described below, monoalkyltin triamide compositions can also serve as precursors for monoalkyltin trialkoxide and monoalkyltin triamide compositions. Monoalkyltin trialkoxide compositions can also be convenient precursors for forming monoalkyltin trialkoxide compositions. Monoalkyltin trialkoxide compositions can be desirable components in precursor patterning composition solutions because they undergo in situ hydrolysis and condensation to form monoalkyltin oxo-hydroxo compositions, with alcohol by-products that are generally suitably volatile for removal consistent with in situ hydrolysis.

[0019] Any one of the three methods described herein can be used to directly synthesize monoalkyltin triamide compositions relatively low in polyalkyl contaminants. The method using the Zn reagent was specifically developed for synthesizing high-purity monoalkyltin triamides containing secondary alkyl groups. Furthermore, at least some of the monoalkyltin triamide compositions can be further purified using fractional distillation. The synthesis of monoalkyltin triamide compositions from monoalkyltin triamide compositions provides an additional method for reducing polyalkyl contaminants. These methods can be combined to further reduce polyalkyl contaminants.

[0020] Monoalkyltin triamide compositions can generally be represented by the formula RSn(NR')3, where R and R' are independently alkyl or cycloalkyl having 1 to 31 carbon atoms, where one or more carbon atoms are optionally substituted with one of several heteroatom functional groups containing O, N, Si, and / or halogen atoms, or the alkyl or cycloalkyl is further functionalized with a phenyl or cyano group. In some embodiments, R' can contain ≦10 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, or t-amyl. The R group can be a linear, branched (i.e., secondary or tertiary at the carbon atom bonded to the metal), or cyclic hydrocarbyl group. Each R group individually and generally has 1 to 31 carbon atoms, with 3 to 31 carbon atoms for groups with secondary bonded carbon atoms and 4 to 31 carbon atoms for groups with tertiary bonded carbon atoms. In particular, branched alkyl ligands can be desirable for some patterning compositions, where the compound is R 1 R 2 R 3 CSn(NR')3 (where R 1 and R 2 are independently alkyl groups having 1 to 10 carbon atoms, and R 3 where R is hydrogen or an alkyl group having 1 to 10 carbon atoms. As shown below, this representation of the alkyl ligand R can be expressed as R 1 R 2 R 3 The same is applicable to other embodiments having generally CSn(X)3, where X corresponds to a trialkoxide or triamide moiety. In some embodiments, R 1 and R 2 can form a cyclic alkyl moiety, R 3 may also be attached to other groups on the cyclic moiety. Suitable branched alkyl ligands include, for example, isopropyl (R 1 and R 2 is methyl and R 3 is hydrogen), tert-butyl (R 1 , R 2 and R3 is methyl), t-amyl (R 1 and R 2 is methyl and R 3 is -CH2CH3), sec-butyl (R 1 is methyl and R 2 is -CH2CH3, and R 3 is hydrogen), neopentyl (R 1 and R 2 is hydrogen and R 3 is -C(CH3)3), cyclohexyl, cyclopentyl, cyclobutyl, and cyclopropyl. Examples of suitable cyclic groups include, for example, 1-adamantyl (-C(CH2)3(CH)3(CH2)3 or tricyclo(3.3.1.13,7)decane attached to the metal at a tertiary carbon) and 2-adamantyl (-CH(CH)2(CH2)4(CH)2(CH2) or tricyclo(3.3.1.13,7)decane attached to the metal at a secondary carbon). In other embodiments, the hydrocarbyl group can include an aryl or alkenyl group, such as benzyl or allyl, or an alkynyl group. In other embodiments, the hydrocarbyl ligand R can include any group consisting solely of C and H and containing 1 to 31 carbon atoms. For example: linear or branched alkyl (i-Pr((CH3)2CH-), t-Bu((CH3)3C-), Me(CH3-), n-Bu(CH3CH2CH2CH2-)), cyclo-alkyl (cyclo-propyl, cyclo-butyl, cyclo-pentyl), olefin (alkenyl, aryl, allyl), or alkynyl groups, or combinations thereof. In further embodiments, suitable R groups may include hydrocarbyl groups substituted with heteroatom functional groups such as cyano, thio, silyl, ether, keto, ester, or halogenated groups, or combinations thereof.

[0021] The alkyltin trialkoxide composition has the formula RSn(OR 0)3, and alkyltriamide tin compositions can be represented by the formula RSn(NR''COR''')3. The R groups in the formulas for the alkyltin trialkoxide and alkyltriamide tin compositions can be the same R groups as described above for the alkyltin triamide compositions, with the corresponding discussion of these R groups above being copied in their entirety to this paragraph. The alkylamide (-NR''COR''') or alkoxide ligand -OR 0 For R'', R''', and R 0 The groups can independently be hydrocarbon groups having 1 to 10 carbon atoms, such as methyl, ethyl, etc. Also, R'' and R''' can independently be hydrogen.

[0022] In some embodiments, the compositions herein (monoalkyltin triamide, monoalkyltin trialkoxide, or monoalkyltin triamide tin) may have dialkyltin contaminants in an amount of about 4 mole percent or less, based on tin, in further embodiments about 3 mole percent or less, in some embodiments about 2 mole percent or less, in yet other embodiments about 1 mole percent or less, in other embodiments about 0.5 mole percent or less, and in other embodiments about 0.1 mole percent or less. Those of ordinary skill in the art will recognize that additional ranges of dialkyltin contaminants within the above explicit ranges are contemplated and are within the scope of the present disclosure. The level of dialkyltin contaminants can generally be determined using any appropriate analytical technique. In some embodiments, the amount of dialkyltin diamide or dialkyltin dialkoxide may be shown by quantitative NMR to be near or less than 0.1 mole percent. As a result of possible unidentified contaminants, quantification of monoalkyltin compositions may be measured within a few percent, but the relatively small error level of dialkyltin contaminants provides confidence using quantitative NMR as described in the Examples below.

[0023] Monoalkyl Sn precursors are 1 H and 119The monoalkylSn precursors were analyzed without derivatization by Sn NMR spectroscopy. Purity was quantified using the integrals from the NMR spectral peaks of the monoalkylSn precursor relative to an internal standard to ensure that the values ​​accurately reflected the purity of the monoalkylSn precursor. A calibrated 90-degree pulse was used to 1 HNMR and inverse gated 119 Sn{ 1 The samples were irradiated for the {H} NMR experiments. 1 H and 119 Sn{ 1 For both the {H} NMR experiments, inversion recovery experiments were used to measure the T relaxation values ​​of the standards and analytes. The measured T values ​​were used to set a recycle delay time equal to five times the longest T time of the sample, which is the time required for the recycle delay of the nuclei (Z = 1 − e -(経過時間 / T1) ) to equilibrium (Z=1-e -5 = 0.99326). Finally, the reduced intensity of the spectral peaks not located at the center of the spectral window is 119 Sn{ 1 For the {H} NMR experiments, the B1 profile of the NMR spectrometer was measured and interpreted by centering the spectrum between the analyte and the standard. The spectrum was inverse gated to increase the signal-to-noise ratio. 119 Sn{ 1 Detection and quantification of trace Sn impurities was performed using parameters set for H {H} NMR spectroscopy: the spectral center and sweep width were set to calibrated values, and a 30-degree pulse was used to irradiate the sample with a 1-second recycle delay. Linear regression analysis was used to assign quantitative values ​​to the detected low-level Sn impurities. This method provides a 0.1% limit of quantification for dialkyl, tetrakisamido, and tetrakisalkoxide tin impurities relative to monoalkyltin compounds. Quantitative NMR was performed as described by Weber et al., "Method development in quantitative NMR towards metrologically traceable organic certified reference materials used as reference materials." 31P qNMR standards”, Anal.Bioanal.Chem., 407:3115-3123 (2015); and Pauli et al., “Importance of Purity Evaluation and the Potential of Quantitative 1 1 H NMR as a Purity Assay,” J. Medicinal Chemistry, 57, 9220-9231 (2014) (both of which are incorporated herein by reference).

[0024] Generally, the improved process herein for preparing monoalkyltin triamides involves reacting a compound having an alkyl-donating group, also referred to as an alkylating agent, with a tin tetraamide. Desired results are achieved, where the alkylating agent can be a Grignard reagent, a diorganozinc reagent, or a monoorganozinc amide. These syntheses can directly produce monoalkyltin triamides low in polyalkyl contaminants, which can be used to form resists or further purified to reduce contaminant levels even further. In the synthesis method, the alkylating agent selectively replaces the amide group of the tin tetraamide with an alkyl group. In some embodiments, the reaction selectively produces monoalkyltin triamides low in polyalkyltin contaminants, particularly low in dialkyltin contaminants. The described synthesis method improves the selectivity and yield of monoalkyltin triamides by suppressing the formation of dialkyltin by-products. The method is particularly useful for branched alkyl systems. The monoalkyltin triamides low in polyalkyl contaminants can then be used to form monoalkyltin trialkoxides low in polyalkyl contaminants. As discussed further below, the formation of crystalline monoalkyltin triamide compositions offers an alternative method of avoiding polyalkyl contaminants by removing them from the crystals.

[0025] For the reaction to form a monoalkyltin triamide compound, the tin tetraamide compound can be obtained commercially or synthesized using known techniques. For example, tetrakis(dimethylamido)tin, Sn(NMe2)4, is available from Sigma-Aldrich. For the synthesis of monoalkyltin compositions, the tin tetraamide reactant in solution can generally have a concentration between about 0.025 M and about 5 M, in further embodiments between about 0.05 M and about 4 M, or in yet other embodiments between about 0.1 M and 2 M. Those skilled in the art will recognize that additional ranges of reactant concentrations within the above explicit ranges are contemplated and within the scope of the present disclosure. Generally, the related reaction to introduce alkyl ligands onto Sn can be initiated using tin tetraamide in solution in a reactor under an inert gas purge and in the dark. In an alternative embodiment, some or all of the tin tetraamide reactant is added stepwise, in which case a higher concentration in the stepwise added solution may be appropriate, and the concentrations may not be directly related to the concentration in the reactor, as the concentration may be transient.

[0026] The alkylating agent is generally added in an amount relatively close to the stoichiometric amount. In other words, the alkylating agent is added to provide the molar equivalent of one alkyl group per tin atom. If the alkylating agent is capable of providing multiple alkyl groups, such as a diorganozinc compound capable of providing two alkyl groups per zinc atom, the stoichiometric amount of the alkylating agent is adjusted accordingly to provide approximately one alkyl group for each tin atom. Thus, a diorganozinc compound on the order of one mole of Zn per two moles of tin is required. The amount of alkylating agent can be about ±25%, about ±20%, or about ±15% of the stoichiometric amount of the reagent, or in other words, the stoichiometric amount of the reagent plus or minus a selected amount to achieve the desired process performance. One of ordinary skill in the art will recognize that additional ranges of relative amounts of alkylating agent within the above explicit ranges are contemplated and are within the scope of the present disclosure.

[0027] Examples 2 and 3 use a near-stoichiometric amount of alkylating agent, while Examples 1 and 4 use about 110% (i.e., 100% + 10%) of the alkylating agent. The alkylating agent dissolved in an organic solvent can be added to the reactor in stages, for example, dropwise or in a stream, at a suitable rate to control the reaction. The rate of addition can be adjusted to control the reaction process, for example, over a period of about 1 minute to about 2 hours, and in further embodiments, about 10 minutes to about 90 minutes. The concentration of the alkylating agent in the addition solution can be adjusted within a reasonable value, taking into account the rate of addition. Essentially, the alkylating reagent can be initiated in the reactor by the staged addition of tin tetraamide. Those skilled in the art will recognize that additional ranges of alkylating agents and addition times within the above explicit ranges are contemplated and are within the scope of the present disclosure.

[0028] The reaction to introduce alkyl ligands onto the tin atom can be carried out in a low-oxygen, substantially oxygen-free, or oxygen-free environment; an active inert gas purge can provide a suitable atmosphere, such as an anhydrous nitrogen purge or argon purge. The following additives have been observed to reduce the addition of secondary alkyl groups to tin: pyridine, 2,6-lutidine, 2,4-lutidine, 4-dimethylaminopyridine, 2-dimethylaminopyridine, triphenylphosphine, tributylphosphine, trimethylphosphine, 1,2-dimethoxyethane, 1,4-dioxane, and 1,3-dioxane. Other neutral coordinating bases may function similarly. The reaction can optionally further include about 0.25 to about 4 moles of neutral coordinating base per mole of tin. The reaction can be shielded from light during the reaction. The reaction can be carried out in an organic solvent, such as an alkane (e.g., pentane or hexane), an aromatic hydrocarbon (e.g., toluene), an ether (e.g., diethyl ether, C2H5OC2H5), or a mixture thereof. The solvent can be anhydrous to avoid reaction with water. The reaction typically takes place for about 15 minutes to about 24 hours, in a further embodiment, about 30 minutes to about 18 hours, and in yet another embodiment, about 45 minutes to about 15 hours. The temperature during the reaction can be between about -100°C and about 100°C, in a further embodiment, about -75°C to about 75°C, and in yet another embodiment, about -60°C to about 60°C. Cooling or heating can be used to control the reaction temperature within the desired range, and control of the addition rate of the reactants can be used to affect temperature development during the course of the reaction. The product monoalkyltin triamide is generally an oil that can be purified using vacuum distillation. Typical yields have been observed to be about 50 to 85 percent. Those of skill in the art will recognize that additional ranges of concentrations and process conditions within the above stated ranges are contemplated and are within the scope of the present disclosure.

[0029] The alkylating agent can be a Grignard reagent, a diorganozinc reagent, or a monoorganozinc amide. The Grignard reagent can be an organomagnesium halide. Specifically, the Grignard reagent in the described reaction can be RMgX, where X is a halide, typically Cl, Br, or I. R can be alkyl or cycloalkyl and can have 1 to 31 carbon atoms, and generally, R can be more fully described above for the R portion of the product composition, as if incorporated in its entirety for this discussion. For example, the alkyl or cycloalkyl can be branched, contain aromatic groups, and / or have one or more heteroatom functional groups containing atoms such as O, N, Si, and / or halogens. Grignard reagents are commercially available or can be synthesized using known methods. Commercial sources include American Elements Company, Sigma-Aldrich, and many others.

[0030] In some embodiments, the alkylating agent is a diorganozinc reagent. The diorganozinc reagent can donate two alkyl groups to the tin, so the amount of diorganozinc reagent is adjusted for differences in molar equivalents. Specifically, the diorganozinc reagent can be RIZn. R can be an alkyl or cycloalkyl having 1 to 31 carbon atoms. The R groups can be more fully defined above for the R portion of the product composition, and the above discussion of R groups related to the product monoalkyltin compounds is considered part of this discussion as if reproduced here. For example, the alkyl or cycloalkyl can be branched and can have one or more heteroatom functional groups containing atoms such as O, N, Si, and / or halogens. Dicycloheptylzinc ((CH 13 )2Zn) reactants are exemplified below. Diorganozinc compounds are commercially available or can be synthesized using known techniques. Commercial sources include, for example, Alfa Aesar, Sigma-Aldrich, Rieke Metals (Nebraska, USA), and Triveni Chemicals (India). The example reactants were synthesized.

[0031] In further embodiments, the alkylating agent is monoorganozinc amide (RZnNR'2). R can be alkyl or cycloalkyl, generally having 1 to 30 carbon atoms. The R group may be more fully defined above for the R portion of the product composition, and the above discussion of R groups related to the product monoalkyltin compounds is considered part of this discussion as if reproduced here. For example, the alkyl or cycloalkyl may be branched and may have one or more carbon atoms substituted with one or more heteroatom functional groups containing atoms such as O, N, Si, and / or halogen. In some embodiments, R' is an alkyl or cycloalkyl group, which may be substituted with a heteroatom. In some embodiments, R' may have 1 to 8 carbon atoms, in some embodiments 1 to 5 carbon atoms, and in yet other embodiments 1 to 3 carbon atoms. R' may also be a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, or t-amyl group. Monoorganozinc amides can be synthesized, for example, from alkylzinc halides (RZnX, X=I, Br, Cl) and lithium amide (LiNR'2), which are commercially available reagents from Sigma-Aldrich.

[0032] Monoalkyltin triamides produced using the methods described above or other methods not explicitly described herein can be further purified using fractional distillation. To reduce the temperature of the distillation process, the pressure can be reduced, for example, to a pressure of about 0.01 Torr to about 10 Torr, in further embodiments, about 0.05 Torr to about 5 Torr, and in further embodiments, about 0.1 Torr to about 2 Torr. Suitable fractionation columns having a volume appropriate for the process can be used and are commercially available. The temperature can be controlled in the vessel holding the purified material and along the column to achieve the desired separation. Thermal conditions for one embodiment are shown in Example 8 below; these conditions can be easily generalized for other compositions based on the teachings herein. If the dialkyltin triamide contaminant has a higher boiling point than the monoalkyltin triamide, the monoalkyltin triamide can be separated and removed during the distillation process. While fractions can be taken with large amounts of liquid removed during the fractional distillation steps, Example 8 demonstrates good separation in reasonable yields containing no detectable contaminants. If the dialkyltintriamide contaminant has a lower boiling point than the monoalkyltintriamide, the dialkyltintriamide can be separated and removed by collecting and discarding the earlier fractions during the distillation process.

[0033] Monoalkyltin trialkoxides can be prepared by reacting the corresponding monoalkyltin triamide with an alcohol and a base in a nonaqueous solvent. Using the process described herein, the low polyalkyltin contaminants in the monoalkyltin triamide can be transferred to the product monoalkyltin trialkoxide, resulting in a product monoalkyltin trialkoxide that essentially has the above-mentioned molar percentage of low dialkyltin contaminants. Suitable organic solvents include, for example, alkanes (e.g., pentane or hexane), aromatic hydrocarbons (e.g., toluene), ethers (e.g., diethyl ether, C2H5OC2H5), or mixtures thereof. The alcohol is selected to provide the desired alkoxide group, such that the alcohol ROH introduces an -OR group as a ligand attached to the tin. Suitable R group candidates are provided above, and the alcohols are shown accordingly. While an example using t-amyl alcohol is given below, other alcohols can be similarly used to provide the desired -OR alkoxide ligand. The alcohol can be provided in approximately stoichiometric amounts. Since alcohol is used to replace three amide groups, 3 molar equivalents of alcohol is the stoichiometric amount. Generally, the amount of alcohol can be at least about -5% stoichiometric equivalent, and in further embodiments at least about stoichiometric equivalent, although a large excess of alcohol can be used. Example 5 was carried out using 3.33% more alcohol than stoichiometric equivalent, i.e., 3.1 moles of alcohol per mole of mono-alkyltin triamide.

[0034] To facilitate purification of the product alkyltin trialkoxide, a tetradentate chelating agent can be added to coordinate unreacted tin tetraamide species to form a complex that will not vaporize during distillation. For example, TREN, triethylenetetramine (trien), or other tertadentate nonplanar coordinating ligands can be used to complex with the unreacted species to facilitate purification. The coordinating ligand can be added in an amount of about 0.5 mol % to about 15 mol %, and in further embodiments, about 1.0 mol % to about 10 mol %, based on the molar amount of tin, at a selected time from the start of the reaction to any time before distillation. It has also been found that tetradentate nonplanar coordinating ligands such as TREN can also be effective in complexing with tin tetraalkoxide compounds to prevent their distillation. Generally, it will be desirable to have at least approximately stoichiometric amounts of tetradentate chelating agent to prevent the distillation of the respective tin tetraamide. Thus, the amount of tetravalent complexing agent for a given amount of tetra-amide can be about a 1:1 molar ratio, or in some embodiments, at least about 95 mole percent, in further embodiments about 98 mole percent to about 200 mole percent, and in yet other embodiments about 99 mole percent to about 120 mole percent of tetravalent complexing agent per mole of tin tetra-amide. Thus, tetradentate nonplanar ligands can be effective in improving the purification of monoalkyltin trialkides from either the tetra-amide or the tetraalkoxide tin compound. Those skilled in the art will recognize that additional ranges of reactant amounts within the above explicit ranges are contemplated and are within the scope of the present disclosure. If necessary, fractional distillation can be performed to further purify the monoalkyltin trialkoxide from the polyalkyl contaminants.

[0035] While monoalkyltin triamides low in polyalkyl contaminants can be effectively used to form derivatives correspondingly low in polyalkyl contaminants, the synthesis of mono-alkyltin triamides from monoalkyltin triamides can be used to form products with low, if not reduced, contaminant levels of the monoalkyltin triamide, due to the formation of monoalkyltin triamide crystals that can appreciably remove the polyalkyl contaminants. Thus, the synthesis of monoalkyltin triamides provides a supplemental or alternative route to forming compositions low in dialkyltin contaminants. Thus, in some embodiments, monoalkyltin triamides with higher levels of desired contaminants, such as from commercial sources or reaction routes with higher contaminant levels, can be used while still obtaining product compositions low in dialkyltin contaminants. Monoalkyltin triamide tin compounds can be used to form monoalkyltin trialkoxide compositions low in dialkyltin contaminants.

[0036] The reaction involves the addition of an N-alkylamide, such as N-methylacetamide (CH3CONHCH3), to a monoalkyltin triamide. Generally, the N-alkylamide reactant is R a CONHR b (In the formula, R a and R b are independently hydrocarbon groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, etc. The crystal structure of the product compound has been confirmed, and the structure is shown in the examples below. In summary, the amide group in the product is attached to the tin at the nitrogen atom, forming the corresponding ligand structure.

[0037] To control the heat generation and progress of the reaction, the N-alkylamide reactant can be added stepwise, for example, over a period of at least about 2 minutes. The monoalkyltin triamide can be dissolved in an organic solvent at a concentration of about 0.1 M to about 8 M, and in further embodiments, about 0.2 M to about 6 M. Suitable organic solvents include, for example, alkanes (e.g., pentane or hexane), aromatic hydrocarbons (e.g., toluene), ethers (e.g., diethyl ether, C2H5OC2H5), or mixtures thereof. The reaction is exothermic, and the addition of heat is generally not necessary. The reaction product can form crystals, and the reaction can generally be continued for about 20 minutes to 24 hours. After completion of the reaction, the solvent can be removed and the product crystals can be collected. The crystals can be washed and dried. The dialkyltin compound is observed to be removed from the product crystals. A person of ordinary skill in the art will recognize that additional ranges of reactant concentrations, addition times, and reaction times within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0038] For the processing of radiation-sensitive resist compositions, it may be desirable to react monoalkyltriamidotin to form a monoalkyltin trialkoxide compound. Alkali alkoxides can be used to replace triamido ligands with alkoxide ligands by reaction in an organic slurry. When the monoalkyltin trialkoxide compound is formed, it dissolves in organic solvents at concentrations of about 0.01 M to 2 M, and in further embodiments, about 0.04 M to about 1 M. The alkali alkoxide compound can be described as ZOR′ (where Z is an alkali atom such as K, Na, or Li, and —OR′ is an alkoxide group that provides the corresponding R′ group for the RSn(OR′)3 product composition). Some alkali alkoxides are commercially available, for example, from Sigma-Aldrich, and these compounds are highly hygroscopic, so they can be isolated from air. Suitable organic solvents include, for example, alkanes (e.g., pentane or hexane), aromatic hydrocarbons (e.g., toluene), ethers (e.g., diethyl ether, C2H5OC2H5), or mixtures thereof. The alkali alkoxide can be provided in at least a stoichiometric amount, corresponding to three alkoxide groups per tin atom. The reaction can be carried out for about 15 minutes to about 48 hours. The product liquid can be distilled to purify the product. A person of ordinary skill in the art will recognize that additional ranges of concentrations and times within the explicit ranges above are contemplated and are within the present disclosure. [Example]

[0039] Example 1: t-BuSn(NMe 2 ) 3 Synthesis of This example is directed to the synthesis of tin compounds having a t-butyl group attached to the tin replacing the N-methylamide group.

[0040] In an argon-filled glovebox, a 5 L, three-necked, round-bottom flask was charged with Sn(NMe2)4 (827.5 g, 2805 mmol, Sigma). Anhydrous ether (2000 mL) was added to the flask. A quantity of t-BuMgCl (1500 mL, 2.06 M (freshly titrated), 3090 mmol) was added to a separate 2 L, two-necked, round-bottom flask. The flask was stoppered and attached to a Schlenk line. The Sn(NMe2)4 solution was transferred to a 5 L jacketed reactor and stirred at 240 RPM. Using an automated syringe pump, the t-BuMgCl solution was added to the 5 L jacketed reactor at 50 mL min. -1 The temperature of the mixture in the jacketed reactor was maintained at 20°C. After complete addition of the t-BuMgCl solution, the reaction was stirred overnight. The resulting mixture was transferred through a 10 L filter reactor into a 5 L, 3-neck, round-bottom flask equipped with a stir bar. The solids in the 5 L jacketed reactor and filter reactor were washed with pentane (2 x 1 L). The washes were collected in a 5 L, 3-neck, round-bottom flask equipped with a stir bar, and the volatiles were removed under vacuum. After removal of the volatiles, a pale yellow oily suspension was observed, corresponding to the crude product. The flask was brought into a glove box, and the crude product was filtered through a coarse-porosity fritted funnel. The filtrate was transferred into a 2 L, 2-neck, round-bottom flask equipped with a stir bar, stoppered, and transferred to a Schlenk line. The crude product was purified by short-path vacuum distillation in a 1 L receiving flask (500 mTorr, 65-75 °C) to yield 323-604 g, 37-70%, of a colorless oil identified as t-BuSn(NMe) by proton NMR (Figure 1) and 119 Sn NMR (Figure 2) is performed to characterize the product, where the following peaks are observed: 1 H NMR(C6D6,MHz):2.84(s,18H,-NCH3),1.24(s,9H,H3CC-); 119 Sn NMR (C6D6, 186.4 MHz: -85.69). Quantitative proton NMR and tin NMR were performed to determine the purity of the product. 1 H, standard 1,3,5-trimethoxybenzene, purity 94.5(3) mol% (94.5 ± 0.3 mol%) monoalkyltin;119 Sn, standard MeSnPh3, purity 93.5(2) mole % monoalkyltin.

[0041] [Table 1]

[0042] Example 2: CySn(NMe 2 ) 3 Synthesis of (Cy=cyclohexyl) This example is directed to the synthesis of tin compounds bearing a cyclohexyl group from a Zn reagent that replaces the N-methylamide group of Sn(NMe2)4.

[0043] In an argon-filled glovebox, a 250 mL three-neck round-bottom flask (RBF) was charged with Sn(NMe2)4 (5.61 g, 19.0 mmol, Sigma). Anhydrous ether (150 mL) was added to the flask. Separately, a 100 mL RBF was charged with w / LiNMe2 (0.97 g, 19.0 mmol, Sigma) and anhydrous ether (20 mL). CyZnBr (Cy = cyclohexyl, 48.5 mL, 0.392 M, 19.0 mmol, Sigma) was slowly added to the flask to produce CyZnNMe2. Because the reaction is exothermic, the reaction temperature was controlled by the slow addition of CyZnBr. A dropping funnel and reflux condenser were attached to the 250 mL three-neck RBF on a Schlenk line under an active argon purge. The 250 mL RBF was covered with aluminum foil to block light, and the CyZnNMe2 solution was added to the dropping funnel and dispensed dropwise with stirring. After complete addition, the reaction was stirred overnight, and the solvent was removed in vacuo to yield a pale orange oil along with a precipitate. The oil was purified by vacuum distillation (58-62 °C, 150 mTorr). The resulting product was 4.38 g (69% yield) of a colorless oil identified as CySn(NMe2)3. Proton NMR (Figure 3) and 119 Sn NMR (Figure 4) characterizes the product, with the following peaks being observed: 1H NMR(C6D6,500MHz):2.85(s,18H,-NCH3),1.86(m,3H,-CyH),1.69(m,2H,-CyH),1.53(m,3H,-CyH),1.24(m,3H,-CyH); 119 Sn NMR (C6D6, 186.4MHz): -73.77.

[0044] Example 3. (CyHp)Sn(NMe 2 ) 3 Synthesis of (CyHp = cycloheptyl) This example is directed to the synthesis of a tin triamide bearing a cycloheptyl group, as shown in the following formula: In this synthesis, the cycloheptyl group from the zinc reagent (CyHp)Zn replaces the N-methylamide group of Sn(NMe) [ka]

[0045] In an argon-filled glovebox, a 250 mL three-necked round-bottom flask (RBF) was charged with Sn(NMe2)4 (6.49 g, 22.0 mmol, Sigma). Anhydrous ether (150 mL) was added. A dropping funnel and reflux condenser were attached to a 250 mL three-necked RBF on a Schlenk line under an active argon purge. Separately, (CyHp)2Zn (0.351 M, 31.3 mL, 11.0 mmol) was synthesized as follows: 2CyHpMgBr + Zn(OCH3)2. The 250 mL RBF was covered with aluminum foil to block light, and the (CyHp)2Zn solution was added to the dropping funnel under an active argon purge and then dispensed dropwise with stirring. After complete addition, the reaction was stirred overnight. The solvent was then removed in vacuo. The reaction flask was placed in a glovebox, and hexane was added. The solution was filtered over Celite®, and the solvent was removed in vacuo to yield a colorless oil along with a precipitate. The oil was purified by vacuum distillation (82-86 °C, 180 mTorr). The resulting product was 4.01 g (52% yield) of a colorless oil identified as (CyHp)Sn(NMe2)3. Proton NMR (Figure 5) and 119Sn NMR (Figure 6) characterizes the product, with the following peaks being observed: 1 H NMR(C6D6,500MHz):2.84(s,18H,-NCH3),2.01(m,2H,-CyHpH),1.82(m,1H,-CyHpH),1.69-1.23(m,10H,-CyHpH); 119 Sn NMR (C6D6, 186.4MHz): -66.93.

[0046] Example 4. t-BuSn(NMe) with additional base 2 ) 3 Preparation of This example demonstrates the synthesis of a tin compound by the reaction of a Grignard reagent with Sn(NMe2)4 in the presence of a base. [ka]

[0047] In an argon-filled glovebox, a 5 L three-necked RBF was charged with Sn(NMe2)4 (539.0 g, 1.827 mol, Sigma). Approximately 3 L of anhydrous diethyl ether and pyridine (289.1 g, 3.66 mol) were added to the flask. The flask was stoppered with glass stoppers on two of the necks, and a vacuum adapter was attached to the third neck. Separately, a 2 L two-necked RBF was charged with 1 L of t-BuMgCl (Grignard reagent) measured in a volumetric flask (2.01 M (titrated), 2.01 mol, Sigma). On an argon-filled Schlenk line, a 5 L jacketed Chemglass™ reactor was prepared for high vacuum and thermal reaction. The reactor was backfilled with argon, and then the jacket around the reactor vessel was cooled to -30 °C.

[0048] The contents of the 5 L, 3-neck RBF were transferred to a Chemglass™ reactor via polyethylene (PE) tubing under positive argon pressure. Stirring was initiated using an overhead stirrer, and the reaction was allowed to cool to -15°C. On the Schlenk line, the Grignard reagent was added via polyethylene (PE) tubing over 20-30 minutes using positive argon pressure while maintaining the internal reaction temperature below 5°C. A deep orange color and precipitate formed. After complete addition, the reaction was allowed to reach room temperature overnight while shielding it from light with aluminum foil.

[0049] After overnight reaction, the reaction color was pale yellow. The solvent was removed in vacuo with the aid of a heating jacket at 30-35°C. After solvent removal, anhydrous pentane (approximately 2.5 L) was added to the reactor through polyethylene tubing under positive argon pressure, and the solids were thoroughly mixed using an overhead stirrer. The reaction product dispersed in pentane was transferred to a 10 L filter reactor through polyethylene tubing using positive argon pressure. The reaction product was filtered and then transferred through the polyethylene tubing into a 3 L RBF. The pentane solvent was removed in vacuo from the resulting pale yellow filtrate, leaving a yellow oil. The oil was transferred to a 1 L Schlenk flask and vacuum distilled using a short-path distillation head (50-52°C, 300 mTorr) to yield 349.9 g (62%) of a colorless oil. Figure 7 ( 1 HNMR) and Figure 8 ( 119 Sn NMR resembles Figures 1 and 2 and shows that the product consists of mono-alkyl species in equilibrium with Sn(NMe2)4. Quantitative proton and tin NMR were performed using selected standards to determine the purity of the product. qNMR: 1 H, standard 1,3,5-trimethoxybenzene, 89.9(7) mole % purity monoalkyltin; 119 Sn, standard MeSnPh3, purity 93.6(4) mol% monoalkyltin.

[0050] [Table 2]

[0051] Example 5. t-BuSn(NMe 2 ) 3 High purity monoalkyl alkoxide t-Bu from Preparation of Sn(OtAm) This example demonstrates the synthesis of monoalkyltin trialkoxides from the corresponding monoalkyltin triamides by the following reaction: [ka]

[0052] In a glovebox, a 2 L, two-necked RBF was charged with approximately 500 mL of pentane from Example 4 and t-BuSn(NMe2)3 (329.4 g, 1.07 mol). The flask was tared on a balance, and tris(2-aminoethyl)amine (3.91 g, 26.7 mmol) was added directly to the reaction mixture via syringe. The amine complexes with the tin tetrakisamide during the reaction and purification, removing the tin tetrakisamide. If it is not necessary to remove the tin tetrakisamide from the system, the product of Example 1 can be used to synthesize additional monoalkyltin products. The reaction sequence can be continued using the material synthesized according to Example 1. A magnetic stir bar was added, and the reaction was then sealed and brought to a Schlenk line. The flask was cooled in a dry ice / isopropanol bath. Separately, a 1 L Schlenk flask was charged with tert-amyl alcohol (2-methyl-2-butanol) (292.2 g, 3.315 mol) and a small amount of pentane, then attached to a Schlenk line. The alcohol / pentane solution in the Schlenk flask was transferred via cannula to a reaction flask with an outlet purge to a mineral oil bubbler connected in-line to an acid trap solution for degassed NMeH. After complete addition of the alcohol, the reaction was allowed to reach room temperature and stirred for 1 hour. After 1 hour of reaction, the solvent was removed in vacuo, and the product was vacuum distilled (95-97 °C, 500 mTorr) to yield 435 g (93%) of a colorless oil. Figure 9 ( 1 HNMR) and Figure 10 ( 119 Sn NMR) shows the NMR spectrum of the final product t-BuSn(Ot-Am)3, in which the following peaks are observed: 1H NMR(C6D6,500MHz):1.61(m,6H,-OC(CH3)2CH2),1.37(m,18H,-OC(CH3)2),1.28(s,9H,-C(CH3)3),1.01(m,9H,-OC(CH3)2CH2CH 3 ); 119 Sn NMR (C6D6, 186.4 MHz): -240.70. Quantitative proton NMR was performed to determine the purity level of the product. qNMR: 1 H, standard 1,3,5-trimethoxybenzene, purity 97.7(3)%; 119 Sn, standard MeSnPh3, 99(1) mol% monoalkyltin.

[0053] Example 6 Preparation of t-butyltris(N-methylacetamido)tin(IV) This example demonstrates the synthesis of a monoalkyltriamidotin composition by the reaction of t-BuSn(NMe2)3 with N-methylacetamide. [ka]

[0054] In a glovebox, a 250 mL Schlenk round-bottom flask was charged with t-BuSn(NMe2)3 (40.13 g, 130 mmol) containing 1% t-BuSn(NMe2)2. t-BuSn(NMe2)3 was synthesized according to Example 1 or Example 4. 50 mL of toluene was added to the round-bottom flask, followed by the slow addition of N-methylacetamide (28.6 g, 391 mmol, Sigma) to control heat generation. An additional 30 mL of toluene was used to wash all of the N-methylacetamide out of the reaction flask. The flask was sealed with a ground glass stopper and transferred to a Schlenk line. Over several hours, large crystals precipitated from the solution. The toluene was removed via cannula under an active argon purge. The white crystals were removed and washed twice with 100 mL of pentane via cannula, which was subsequently removed. They were dried in vacuo to yield 40.6 g (80%) of t-butyltris(N-methylacetamido)tin(IV). Figure 11 shows the crystalline structure of the solid, confirmed by X-ray diffraction. The proton NMR spectrum, as shown in Figure 12, yields the following peaks: 1 H NMR (CD, 500 MHz): 2.52 (s, 9H, -NCH), 2.01 (m, 2H, -CyHpH), 1.74 (s, 9H, -(HC)CSn), 1.69 (s, 9H, -CHCO). As shown in Figure 13, the tin NMR spectrum yields the following peaks: 119 Sn NMR (C6D6, 186.4MHz):-346.5.

[0055] Example 7 t-BuSn(Ot-Am) 3 Synthesis of This example demonstrates the synthesis of t-BuSn(Ot-Am) from the t-butyltris(N-methylacetamido)tin(IV) product of Example 6.

[0056] In a glovebox with an argon atmosphere, a 3 L round-bottom flask was charged with t-butyltris(N-methylacetamido)tin(IV) (100 g, 255 mmol) from Example 6, followed by NaOtAm (98 g, 890 mmol, Sigma). The mixture was slurried in 1.5 L of pentane using a magnetic stirrer and a 2.5-inch long egg-shaped stir bar. The slurry thickened and became milky white after 30-60 minutes. Stirring was continued for approximately 16 hours. The slurry was then filtered through a medium-porosity fritted funnel in the glovebox, and the recovered solids were washed twice with 100 mL of pentane. The retained solids formed a very fine cake during filtration, so occasional stirring was used to facilitate recovery.

[0057] The filtrate was transferred to a two-necked, 2 L flask equipped with a stir bar, which was then sealed with a ground stopper and a Schlenk inlet adapter. The flask was removed from the glove box and connected to a vacuum line in a fume hood, where excess solvent was removed under vacuum. The crude product was then purified by vacuum distillation and collected in a 100 mL Schlenk storage flask. For the vacuum distillation, an oil bath was set to 150°C. The product was distilled at 300 mTorr and a temperature of 98-102°C to yield 74 g (66%) of product. As shown in Figure 14, the proton NMR spectrum showed the following shifts: 1 H NMR shifts [400 MHz, C6D6]: 1.64 (q, 6H, -CH2), 1.39 (s, 18H, -C(CH3)2), 1.29 (s, 9H, (CH3)3CSn), 1.03 (t, 9H, -CCH3). As shown in Figure 15. 119 The Sn NMR spectrum showed the following peaks: 119 Sn NMR shift [149.18 MHz, C6D6]: -241.9. Quantitative NMR was performed to determine purity following evaluation of standards. 1 HqNMR, standard 1,3,5-trimethoxybenzene, purity 97.3(1) mol% monoalkyl.

[0058] [Table 3]

[0059] Example 8 Fractional distillation and purification This example demonstrates the effectiveness of fractional distillation to purify t-BuSn(NMe2)3 by its separation from a mixture of t-Bu2Sn(NMe2)2 and t-BuSn(NMe2)3.

[0060] In a glovebox, a 3000 mL three-neck round-bottom flask (RBF) was charged with t-BuSn(NMe2)3 (1420 g total, 4.6 mol) containing approximately 3.27% t-Bu2Sn(NMe2)2; the sample was prepared using a modified t-BuMgCl:Sn(NMe2)4 ratio by the method described in Example 1. Glass stoppers were placed on two necks of the RBF, and the third neck was attached to a Schlenk line. Separately, a 5 L Chemglass jacketed reactor was fitted with an overhead stirrer, a temperature probe, and two 18-inch distillation columns, one above the other. The distillation columns were fitted with Pro-Pak™ (ThermoScientific, 0.24 in 2 ) was packed with high-efficiency distillation column packing. A short-path distillation head with a temperature probe was attached to the top of the distillation column. The top of the short-path head was then connected to a three-arm cow joint holding three 500 mL Schlenk flasks (Schlenk bombs). The reactor was evacuated and backfilled with argon three times. The t-Bu2-rich mixture was added to the reactor via a large cannula under argon. Distillation was initiated by heating the jacketed reactor between 110 and 120 °C under reduced pressure (500 mTorr). The temperature at the bottom of the distillation column was measured to be between 95 and 100 °C, while the temperature at the top of the column was maintained between 58 and 60 °C. Three fractions were collected, each containing 100 mL of t-Bu2. 119 The results were analyzed by Sn NMR spectroscopy. Figures 16-19 show the results of the pooled sample (Figure 16) and each of the three fractions (Figures 17-19, respectively). 119 Figure 1 shows a plot of the Sn NMR spectrum. All three fractions showed no NMR signal for t-Bu2Sn(NMe2)2. The total yield combining all fractions was 850 g (60%).119 Sn NMR(C6D6, 186.4MHz):-85.45

[0061] Example 9. Vacuum distillation purification This example demonstrates the effectiveness of vacuum distillation to purify t-BuSn(OtAm)3 to produce an amide-free composition, as demonstrated by its separation from a mixture of Sn(OtAm)4 and t-BuSn(OtAm)3. Tris(2-aminoethyl)amine (TREN) was used as a purification aid.

[0062] In a glovebox with an argon atmosphere, a 100 mL round-bottom Schlenk flask was charged with t-BuSn(OtAm)3 [25 g, 55.825 mmol] contaminated with approximately 1.3% Sn(OtAm)4, followed by 10 mL of anhydrous pentane. The mixture was stirred using a magnetic stirrer before TREN [0.112 g, 0.7686 mmol] was added using a glass transfer pipette. The flask was sealed using a glass stopper for the 24 / 40 ST joint and a Teflon valve for the side arm port. The flask was connected to a Schlenk line, placed under inert gas (nitrogen), and placed in a silicone oil bath. Stirring and heating control were achieved using a Heidolph HEI-TEC stir plate with a Pt / 1000 temperature probe, allowing feedback temperature control for the oil bath. The bath was maintained at 45 °C before excess solvent was removed under vacuum. A short-path vacuum distillation apparatus was set up using a 50 mL Schlenk flask as the receiving vessel, with a millitorr vacuum gauge used to verify solvent removal. Vacuum distillation was carried out at 300 mTorr absolute pressure, a bath temperature of 150 °C, and a vapor temperature ranging from 94 to 98 °C.

[0063] Sn(O t The theoretical recovery assuming 100% removal of Am)4 was 24.66 g, and the distillate recovered was 21.70 g, giving a recovery of 88%. 119 The Sn NMR spectra are shown in Figure 20 (baseline) and Figure 21 (purified). 119Sn NMR shift [149.18MHz, C6D6]: t BuSn(O t Am)2:-113 ppm; t BuSn(O t Am)3:-241 ppm; Sn(O t Am)4:-370 ppm.

[0064] The above-described embodiments are intended to be illustrative and not limiting. Additional embodiments are within the scope of the claims. Moreover, while the present invention has been described with reference to specific embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present invention. Any incorporation by reference of the above documents is limited so as not to incorporate subject matter contrary to the explicit disclosure herein. To the extent that particular structures, compositions, and / or processes are described herein in terms of components, elements, ingredients, or other divisions, it should be understood that the disclosure herein extends to particular embodiments that may include additional features that do not alter the basic nature of the subject matter, as suggested in the discussion, as well as embodiments that include particular components, elements, ingredients, other divisions, or combinations thereof, and embodiments that consist essentially of such particular components, ingredients, ingredients, other divisions, or combinations thereof, unless otherwise indicated. It should be noted that the present invention as described above includes the following aspects. First aspect: Chemical formula RSn(OR') 3 Monoalkyltin trialkoxide compounds represented by the formula RSn(NR' 2 ) 3 and a monoalkyltin triamide compound represented by and 4 mole percent or less, based on the total amount of tin, of a dialkyltin compound, wherein: R is a hydrocarbyl group having 1 to 31 carbon atoms, and The composition wherein R' is a hydrocarbyl group having 1 to 10 carbon atoms. Second aspect: R is R 1 R 2 R 3 C-(wherein, R 1 and R 2 are independently alkyl groups having 1 to 10 carbon atoms, and R 3 is hydrogen or an alkyl group having 1 to 10 carbon atoms). Third embodiment: R is methyl (CH 3 -), ethyl (CH 3 CH 2 -), isopropyl (CH 3 CH 3 HC-), tert-butyl ((CH 3 ) 3 C-), tert-amyl (CH 3 CH 2 (CH 3 ) 2 C-), sec-butyl (CH 3 (CH 3 CH 2 )CH-), neopentyl (CH 3 ) 3 CCH 2 -), cyclohexyl, cyclopentyl, cyclobutyl, or cyclopropyl. Fourth Aspect: The composition according to any one of the first to third aspects, wherein R' contains a methyl group, an ethyl group, an isopropyl group, or a t-butyl group. Fifth Aspect: The composition according to any one of the first to third aspects, wherein R' comprises a t-amyl group. Sixth Aspect: The composition according to any one of the first to fifth aspects, comprising about 1 mol % or less of a dialkyltin compound. Seventh aspect: The composition according to any one of the first aspect to the sixth aspect, which contains a monoalkyltin triamide. Eighth aspect: A solution containing the composition according to any one of the first aspect or the fourth to seventh aspects, and an organic solvent. Ninth aspect: The solution according to the eighth aspect, having a concentration of about 0.005 M to about 0.5 M, wherein the solvent contains an alcohol. 10th embodiment: R is methyl (CH 3 -), ethyl (CH 3 CH 2 -), isopropyl (CH 3 CH 3 HC-), tert-butyl ((CH 3 ) 3 C-), tert-amyl (CH 3 CH 3 (CH 3 ) 2 C-), sec-butyl (CH 3 (CH 3 CH 2 )CH-), neopentyl (CH 3 ) 3 CCH 2 -), cyclohexyl, cyclopentyl, cyclobutyl, or cyclopropyl, and R' comprises a methyl group, an ethyl group, an isopropyl group, a t-butyl group, or a t-amyl group. 11th Aspect: A method for selectively forming monoalkyltin trialkoxide compounds with reduced dialkyltin contamination, comprising: The composition according to the seventh aspect is reacted with an alcohol represented by the formula HOR″ in an organic solvent to form RSnOR″ 3 wherein R″ is independently a hydrocarbyl group having 1 to 10 carbon atoms to form a product composition having 4 mole % or less of dialkyltin compounds based on the total amount of tin. Twelfth embodiment: Formula RSn-(NR'COR'') 3 wherein R is a hydrocarbyl group having 1 to 31 carbon atoms; and wherein R' and R'' are independently hydrocarbyl groups having 1 to 10 carbon atoms. Thirteenth aspect: The composition according to the twelfth aspect, wherein R' is a methyl group. 14th aspect: The composition according to the 12th aspect or the 13th aspect, wherein R″ is a methyl group. 15th embodiment: R is methyl (CH 3 -), ethyl (CH 3 CH 2 -), isopropyl (CH 3 CH 3 HC-), tert-butyl ((CH 3 ) 3 C-), t-amyl (CH 3 CH 3 (CH 3 CH 2 )C-), sec-butyl (CH 3 (CH 3 CH 2 )HC-), neopentyl (CH 3 ) 3 CCH 2 -), cyclohexyl, cyclopentyl, cyclobutyl, or cyclopropyl. 16th aspect: A composition according to any one of the 12th aspect to the 15th aspect, which is crystalline and contains about 1 mole percent or less of dialkyltin contaminants. 17th aspect: RMgX, R 2 Zn, RZnNR' 2 or a combination thereof in a solution containing an organic solvent. 2 ) 4 and reacting the compound with wherein R is a hydrocarbyl group having 1 to 31 carbon atoms; X is a halogen, and A method for forming a monoalkyltin triamide compound comprising the step of: R' is a hydrocarbyl group having 1 to 10 carbon atoms. 18th embodiment: The method according to the 17th embodiment, wherein the solution has a tin concentration of between about 0.01M and about 5M. A nineteenth aspect: The method according to the seventeenth or eighteenth aspect, wherein the organic solvent comprises an alkane, an aromatic hydrocarbon, an ether, or a mixture thereof. A 20th aspect: The method according to any one of the 17th to 19th aspects, wherein the solution has a concentration of the alkylating agent of about ±25% relative to the stoichiometric reaction of the tin reagent and the alkylating agent. Aspect 21: The method according to any one of Aspects 17 to 20, wherein the reaction is carried out under an inert atmosphere by stepwise addition of the alkylating agent shielded from ambient light. 22nd aspect: The method according to any one of the 17th aspect to the 21st aspect, wherein the alkylating agent is added stepwise over a period of 10 minutes to 90 minutes. 23rd aspect: The method according to any one of the 17th aspect to the 21st aspect, wherein the reaction is carried out at a temperature of −100° C. to 100° C. for 15 minutes to 24 hours. 24th Aspect: The method according to any one of the 17th to 23rd aspects, wherein the solution further contains 0.25 to 4 molar equivalents of a neutral coordinating base relative to the tin. 25th aspect: RSn(NR' 2 ) 3 is reacted with an alcohol represented by the formula HOR'' in an organic solvent to give RSnOR'' 3 forming RSn(NR' 2 ) 3 1. A process for selectively forming monoalkyltin trialkoxide compounds with reduced contamination of dialkyltins, comprising the steps of: a reactant having about 4 mole % or less of dialkyltin contaminants and being the product of the process of the first aspect above, wherein R is a hydrocarbyl group having 1 to 31 carbon atoms, and R′ and R″ are independently hydrocarbyl groups having 1 to 10 carbon atoms. 26th embodiment: The method according to the 25th embodiment, wherein the reaction is carried out using a tetradentate chelating agent in an amount of about 0.5 mol % to about 15 mol % relative to the molar amount of the tin. 27th embodiment: Chemical formula RSn(NR' 2 ) 3 with an amide (R"CONHR"") in an organic solvent, wherein R is a hydrocarbyl group having 1 to 31 carbon atoms, and R', R", and R'" are independently hydrocarbyls having 1 to 8 carbon atoms; Formula RSn(NR'''COR'') 3 and collecting a solid product represented by: 28th embodiment: The method according to the 27th embodiment, wherein the monoalkyltintriamide has an initial concentration of about 0.1 M to about 8 M, and the solvent is an alkane, an aromatic hydrocarbon, or an ether. 29. The method of claim 27 or 28, wherein the amide is added stepwise over a period of at least about 2 minutes. A 30th aspect: The method according to any one of the 27th to 29th aspects, wherein the solid product is crystalline and has about 1 mole percent or less of dialkyltin compound contaminants relative to the tin. Thirty-first embodiment: monoalkyltriamide tin compounds (RSn(NR'''COR'') 3 ) with an alkali alkoxide compound (QOR', where Q is an alkali metal atom) in an organic solvent to give a compound of the formula RSn(OR') 3 wherein R is a hydrocarbyl group having 1 to 31 carbon atoms, and R', R'', and R''' are independently hydrocarbyl groups having 1 to 10 carbon atoms. A 32nd aspect: The method according to the 31st aspect, wherein the alkoxide donor compound is provided in at least a stoichiometric amount. A 33rd aspect: The method according to the 31st aspect or the 32nd aspect, wherein the solvent is an alkane, an aromatic hydrocarbon, or an ether. Thirty-fourth embodiment: A method for purifying a monoalkyltin trialkoxide, comprising the step of distilling a blend of a monoalkyltin trialkoxide and a tetradentate nonplanar complexing agent. A 35th embodiment: The method according to the 34th embodiment, wherein the tetradentate non-planar complexing agent comprises TREN. A 36th embodiment: The method of the 34th embodiment or the 35th embodiment, wherein the tetradentate nonplanar complexing agent is present in an amount of about 0.5 mol % to about 15 mol % relative to the molar amount of tin. 37th embodiment: The alkyl group is R 1 R2 R 3 C-(wherein, R 1 and R 2 are independently alkyl groups having 1 to 10 carbon atoms, and R 3 is hydrogen or an alkyl group having 1 to 10 carbon atoms). A 38th embodiment: The method according to any one of the 34th embodiment to the 36th embodiment, wherein the alkyl group includes isopropyl, tert-butyl, tert-amyl, sec-butyl, or neopentyl.

Claims

1. Monoalkyltriamide tin compounds (RSn(NR'''COR'') ３ ) with an alkali alkoxide compound (QOR', where Q is an alkali metal atom) in an organic solvent to produce a compound of the formula RSn(OR') ３ wherein R is a hydrocarbyl group having 1 to 31 carbon atoms, and R', R'', and R''' are independently hydrocarbyl groups having 1 to 10 carbons.

2. The method of claim 1, wherein the alkali alkoxide compound is provided in a molar ratio of at least 3:1 to the monoalkyltriamide tin compound.

3. 10. The method of claim 1, wherein the organic solvent is an alkane, an aromatic hydrocarbon, an ether, or a mixture thereof.

4. The method of any one of claims 1 to 3, wherein R comprises methyl (CH 3 -), ethyl (CH 3 CH 2 -), isopropyl (CH 3 CH 3 HC-), tert-butyl ((CH 3 ) 3 C-), tert-amyl (CH 3 CH 2 (CH 3 ) 2 C-), sec-butyl (CH 3 (CH 3 CH 2 )CH-), neopentyl (CH 3 ) 3 CCH 2 -), cyclohexyl, cyclopentyl, cyclobutyl, or cyclopropyl.

5. The method of claim 1, wherein R is tert-butyl.

6. The method of claim 1, wherein R comprises an aryl group or an alkenyl group.

7. The method of claim 1, wherein Q is Li, Na, or K.

8. The method of claim 1, wherein R' is tert-butyl or tert-amyl.

9. The method of claim 1, wherein QOR' is NaOtAm, NaOtBu, KOtAm, or KOtBu.

10. The method of claim 1, wherein R'' and R''' are independently a methyl group, an ethyl group, a propyl group, or an isopropyl group.

11. The method of any one of claims 1 to 3, wherein both R'' and R''' are methyl.

12. The method of any one of claims 1 to 3, further comprising the step of distilling the product compound represented by the formula RSn(OR') 3 .

13. The method of any one of claims 1 to 3, wherein the product compound represented by the formula RSn(OR') 3 is 1 mole percent or less relative to the tin of the contaminant dialkyltin compound.

14. The method of claim 12, wherein the product compound represented by the formula RSn(OR') 3 is 1 mole percent or less relative to the tin of the contaminant dialkyltin compound.

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