Process for the synthesis of tert-butyltris(phenylethynyl)stannane

Abstract

The present application relates to the field of organotin synthesis, in particular to a synthesis method of tert-butyl tris (phenylacetylene) stannane. The synthesis method comprises the following steps: (S1) under an inert atmosphere, mixing aromatic hydrocarbon organic solvent, Lewis acid and organic amine, phenylacetylene uniformly to obtain mixture 1; (S2) under an inert atmosphere, 0-10 DEG C, mixing aromatic hydrocarbon organic solvent, tin tetrachloride, tert-butyl magnesium chloride, ether solvent and morpholine compound uniformly, after the completion of feeding, stirring at 10-15 DEG C to obtain mixture 2; (S3) under an inert atmosphere, 10-15 DEG C, slowly adding mixture 2 into mixture 1, incubating and reacting, after the completion of reaction, post-treatment to obtain product tris (phenylacetylene) tert-butyl tin. The one-pot synthesis process of the present application is prepared by mixing two independent systems, which reduces the material loss caused by the separation process of intermediates and improves the overall yield.

Description

Technical Field

[0001] This invention relates to the field of organotin synthesis, specifically to a method for synthesizing tert-butyltris(phenylethynyl)tinane. Background Technology

[0002] Organotin alkynes are a class of organometallic molecules possessing both an organic conjugated framework and a metal-carbon covalent bond, holding an irreplaceable position in organic optoelectronic functional materials, metal-organic vapor deposition precursors, and fine organic synthesis. In the field of organic optoelectronic materials, arylethynyltin compounds, relying on their intramolecular alkyne conjugated system, can construct conjugated organic semiconductors, organic light-emitting materials, and functional layer materials for organic field-effect transistors via Stille cross-coupling reactions, serving as key building blocks for preparing high-performance π-conjugated functional molecules. In the field of thin film preparation, metal-organic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD) processes impose stringent requirements on precursors. Organotin precursors, with their controllable thermal decomposition and easy impurity removal, are core raw materials for preparing tin oxide thin films, tin-based multi-component composite functional films, and transparent conductive coatings. In the field of coordination chemistry, the Sn-C≡C bond possesses excellent coordination activity, and alkyne-based organotin molecules can serve as ligands to construct novel functional materials such as metal clusters and coordination polymers.

[0003] Asymmetric tri(phenylethynyl)tert-butyltin, with three conjugated phenylethynyl groups and one sterically hindered tert-butyl group simultaneously bonded to the central tin atom, perfectly compensates for the structural defects of symmetric tetra(phenylethynyl)tin and has broad application prospects. The sterically hindered tert-butyl group in the molecule can disrupt the close packing of the molecule, effectively improving the solubility of the product in common organic solvents such as toluene and tetrahydrofuran, making it suitable for solution spin coating and wet synthesis processes; the saturated alkyl group can precisely control the thermal stability and volatility of the molecule, broadening the process adaptability range of tin-based thin film precursors; the molecule retains three highly active Sn-C≡CPh bonds, which can be used to construct complex conjugated photoelectric molecules through coupling reactions, or to assemble novel metal-organic frameworks and metal cluster materials by utilizing the coordination properties of the alkynyl group.

[0004] Achieving selective monoligand exchange of tetra(arylethynyl)tin in a controllable manner has long been a technical challenge. Since the reactivity of four identical Sn-alkynyl bonds is similar, conventional nucleophiles readily induce di- and poly-substituted byproducts, making it difficult to obtain monoalkyl-substituted products with high selectivity.

[0005] Patents WO2019099981 A2 and WO2019195522 A2 report a method for synthesizing tert-butyltris(phenylethynyl)tinane, and the specific synthetic route is as follows:

[0006]

[0007] Existing synthetic methods suffer from poor selectivity, complex byproducts, limited raw materials, unstable processes, and inability to directionally prepare the target asymmetric structure. The industry has consistently lacked a preparation process that offers controllable reactions, mild conditions, high selectivity, and simple operation. This invention presents a one-pot synthetic method that, through time-series control and the steric hindrance self-limiting effect of tert-butyl, precisely achieves the directional construction of triyneyl monoalkyl groups, effectively overcoming the technical shortcomings of existing synthetic routes.

[0008] The literature by Jaumier, Pascale, Jousseaume, et al., "Functional Organotin Alkynides as Precursors of Tin-Based Hybrid Materials," reports a synthetic method for tert-butyltris(phenylethynyl)tinane. The specific synthetic route is as follows:

[0009]

[0010] The conventional synthesis of tri(phenylethynyl)-tert-butyltin often employs a stepwise reaction process, first synthesizing an intermediate using tin tetrachloride, and then reacting it stepwise with tert-butyl alkyl halides to prepare the target product. Compared to the one-pot synthesis process of this invention, this conventional stepwise reaction mode has significant technical drawbacks: poor reaction controllability, numerous side reactions, and difficulty in meeting the requirements of efficient, stable, and scalable preparation. Traditional stepwise reaction processes lack precise system timing control, often employing sequential direct feeding of raw materials. The reaction process lacks an independent pre-reaction system, resulting in uneven instantaneous substrate concentrations, easily triggering disordered multi-substitution side reactions, making it difficult to accurately stop at the single tert-butyl substitution stage, leading to a complex product system and low selectivity for the target product. This process is uncontrollable, the reaction endpoint is difficult to precisely control, greatly increasing the difficulty of subsequent purification, resulting in high material loss, low overall yield, and high preparation costs, making it unsuitable for batch preparation. Traditional stepwise reactions involve a single system throughout the entire process, lacking steric hindrance and self-limiting control mechanisms. This makes it impossible to utilize the steric shielding effect of tert-butyl to suppress multi-level substitution side reactions, resulting in a high proportion of byproducts and poor product purity. Furthermore, the stepwise, multiple feeding operations easily introduce trace amounts of water and oxygen, leading to low process tolerance, poor reaction repeatability, and significant batch-to-batch fluctuations. These methods are only suitable for small-scale experimental preparations in the laboratory, lacking stability and versatility, and completely lacking the potential for industrial-scale application.

[0011] Patent RU2317993A describes a method for synthesizing butyltris(phenylacetyl)tin, which involves reacting butyltrichlorotin with three equivalents of phenylacetylene in the presence of zinc chloride and diethylamine, achieving a yield of 61%. This patent uses butyltrichlorotin as a raw material, which requires preparation. Literature reports that monobutyltrichlorotin is prepared by slowly adding a solution of tert-butylmagnesium chloride in diethyl ether to a SnCl4 solution at low temperature, gradually heating to room temperature, removing the solvent and byproducts, and obtaining monobutyltrichlorotin with a yield of approximately 80%. Therefore, the overall yield is around 50%, and the final product yield remains relatively low. Summary of the Invention

[0012] To address the lack of efficient and controllable synthesis processes for asymmetric tris(phenylethynyl)-tert-butyltin in existing technologies, traditional organotin yne synthesis routes suffer from drawbacks such as poor reaction selectivity, numerous byproducts, difficulty in obtaining raw materials, stringent process conditions, challenging product purification, and difficulty in large-scale preparation. Furthermore, symmetric tetraphenylethynyltin compounds exhibit limited structural diversity and poor performance tunability, failing to meet the diverse application needs of high-end organotin functional materials and organometallic precursors. This invention aims to provide a method for synthesizing tris(phenylethynyl)-tert-butyltin. This invention utilizes a one-pot synthesis strategy, overcoming the technical bottleneck of traditional processes' inability to achieve controllable monosubstituted tetra(phenylethynyl)tin. It enables the highly selective and high-yield preparation of asymmetric alkyl-yneyl composite-substituted organotin compounds, filling a gap in existing technologies. The raw materials used in this method, phenylacetylene, tin tetrachloride, and tert-butylmagnesium chloride, are all inexpensive and readily available, and are common chemical raw materials. The process is simple, the reaction is safe and controllable, the reaction conditions are mild, and the chiral configuration will not racemize, which can effectively maintain the chiral structure of the product. The reaction yield is relatively stable and high, the production operation steps are simplified, the cost is reduced, and large-scale production can be achieved.

[0013] This invention employs a one-pot synthesis process involving independent pre-preparation and subsequent mixing of two systems. This eliminates the need for separation and purification of the in-situ generated tetra(phenylacetyl)tin intermediate, significantly shortening the synthesis steps, reducing material losses during intermediate separation, and improving overall yield. The scheme features a specially designed feeding sequence: first, reaction system 1 containing phenylacetylene, diethylamine, and zinc chloride is constructed; then, system 2 is prepared by mixing tin tetrachloride with tert-butylmagnesium chloride, an ether solvent, and a morpholine compound. The two systems are then slowly mixed, effectively avoiding random side reactions caused by direct mixing of raw materials. The reaction process relies on the steric hindrance effect of the tert-butyl group to achieve controllable single-ligand exchange, significantly suppressing the formation of disubstituted and polysubstituted byproducts, and directionally obtaining the target product, tri(phenylacetyl)tert-butyltin. The entire process operates under mild reaction conditions, with a maximum reaction temperature of only 30.0℃, eliminating the need for high-temperature reflux or ultra-low temperature environments. The entire process requires only conventional nitrogen protection, reducing the need for multiple material transfers and repeated replacement of protective gas, thus lowering the risk of raw material hydrolysis and deactivation caused by water vapor and oxygen. The process is simple to operate, highly tolerant of errors, and caters to both laboratory preparation needs and industrial scale-up potential. It solves the technical pain points of traditional stepwise synthesis processes, such as cumbersome operation, complex by-product systems, and high product separation and purification costs.

[0014] The present invention provides the following technical solutions to solve the above-mentioned technical problems:

[0015] A method for synthesizing tris(phenylethynyl)-tert-butyltin includes the following steps:

[0016] (S1) Under an inert atmosphere, aromatic organic solvent, Lewis acid and organic amine, and phenylacetylene are mixed evenly to obtain mixture 1;

[0017] (S2) Under an inert atmosphere and at 0-10℃, aromatic organic solvent, tin tetrachloride, tert-butylmagnesium chloride, ether solvent, and morpholine compound are mixed evenly. After the addition is complete, the mixture is stirred at 10-15℃ to obtain mixture 2.

[0018] (S3) Under an inert atmosphere, at 10-15℃, mixture 2 is slowly added to mixture 1, and the reaction is maintained at this temperature. After the reaction is completed, post-processing is performed to obtain the product tris(phenylethynyl) tert-butyltin.

[0019] Furthermore, in steps (S1) and (S2), the organic solvent is independently selected from at least one of toluene, xylene, and ethylbenzene. The inert atmosphere is nitrogen and / or argon.

[0020] Further, in step (S1), Lewis acid is selected from at least one of zinc chloride, aluminum trichloride, ferric chloride, boron trifluoride and its diethyl ether complex, and the organic amine is selected from at least one of diethylamine, triethylamine and pyridine;

[0021] Further, in step (S1), the molar ratio of Lewis acid, organic amine, and phenylacetylene is 0.6-0.8:1.2-1.5:1.

[0022] Furthermore, in step (S2), the molar ratio of tin tetrachloride to tert-butylmagnesium chloride is 1:1.3-1.7, for example, 1:1.5-1.6.

[0023] Further, in step (S2), the molar ratio of tin tetrachloride, ether solvent, and morpholine compound is 1:0.5-0.8:0.1-0.2. The ether solvent is selected from at least one of diethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran, and the morpholine compound is selected from at least one of N-methylmorpholine and 2,6-dimethylmorpholine. The inventors have found that adding a certain amount of ether solvent and lithium halide can improve the product yield. A possible reason is that the ether solvent dissolves and stabilizes tert-butylmagnesium chloride through coordination, allowing it to participate in the reaction in a more controllable and milder reactive form, avoiding severe side reactions caused by uneven concentration or local overheating. The morpholine compound can coordinate with tin, effectively inhibiting the formation of byproducts caused by over-substitution and highly selectively guiding the product towards monosubstituted products. The synergistic effect of the ether solvent and morpholine compound increases the yield of the final product, tris(phenylethynyl)-tert-butyltin.

[0024] Further, in step (S3), the amounts of mixture 1 and mixture 2 are such that the molar ratio of phenylacetylene in mixture 1 to tin tetrachloride in mixture 2 is 4-5:1. System 2 is slowly added dropwise to system 1 for 1-4 hours; the reaction is kept at a constant temperature for 8-15 hours, for example, 12 hours.

[0025] Further, in step (S3), the post-treatment involves filtering to obtain a filtrate and a filter cake. The filter cake is washed with an organic solvent, and the eluent and filtrate are combined. The organic phase is collected, washed with water and brine respectively, dried, and concentrated to obtain a crude product. The crude product is added to n-hexane and stirred at 5-10°C, resulting in the precipitation of a white solid, which is the product tris(phenylethynyl)-tert-butyltin. Even further, the organic solvent used for washing is the same as that used in step S1, such as toluene. The brine is a saturated sodium chloride solution.

[0026] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0027] I. This invention employs a one-pot synthesis method, significantly shortening the process: The one-pot synthesis process utilizes two independently pre-prepared systems followed by mixing, eliminating the need for separation and purification of the in-situ generated tetra(phenylacetyl)tin intermediate. This greatly shortens the synthesis steps, reduces material loss during intermediate separation, and improves the overall yield. The operation is simple and the process is stable, suitable for both laboratory preparation and industrial scale-up applications.

[0028] II. The raw materials used in the process of this invention, namely phenylacetylene, tin tetrachloride and tert-butylmagnesium chloride, are all common chemical raw materials with wide availability and low cost.

[0029] Third, the synergistic effect of ether solvents and morpholine compounds reduces side reactions and significantly improves the yield. Attached Figure Description

[0030] Figure 1 The data are the 1H NMR spectra of the product tri(phenylethynyl)tert-butyltin obtained in Example 1.

[0031] Figure 2 This is the HPLC chromatogram of the product tris(phenylethynyl)tert-butyltin obtained in Example 1. Detailed Implementation

[0032] The technical solution of the present invention will be further explained and illustrated below with specific embodiments.

[0033] Example 1

[0034] (S1) Add toluene (500.00 mL, 5.00 V) to a three-necked flask. After stirring, evacuate and replace with nitrogen three times to maintain a nitrogen atmosphere. Then add zinc chloride (156.98 g, 1.15 mol, 3.00 equiv.) and diethylamine (168.45 g, 2.30 mol, 6.00 equiv.). Stir at room temperature for 3.0 h. Then add phenylacetylene (156.81 g, 1.54 mol, 4.00 equiv.). After the addition is complete, system 1 is formed and stirred for later use.

[0035] (S2) Add toluene (1500.00 mL, 15.00 V) to another three-necked flask. After stirring, evacuate and replace with nitrogen three times to maintain a nitrogen atmosphere. Cool the system to 0-10℃ and add tin tetrachloride (100.00 g, 0.38 mol, 1.00 equiv.), tert-butylmagnesium chloride (338.69 mL, 0.58 mol, 1.50 equiv.), tetrahydrofuran (24.3 mL, 0.3 mol, 0.80 equiv.), and N-methylmorpholine (8.4 mL, 0.076 mol, 0.20 equiv.). After the addition is complete, stir at 10-15℃ for 3.0 h to form system 2.

[0036] (S3) Under a nitrogen atmosphere, at 10-15℃, system 2 was slowly added dropwise to system 1, and the addition was completed in 1 hour. The reaction was then maintained at 10-15℃ for 12.0 hours. The reaction was monitored by TLC to ensure the reaction of the starting materials was complete. After the reaction was completed, magnesium sulfate was placed in the funnel, and the reaction system was filtered. The filter cake was washed with toluene (200.00 mL, 2.00 V), and the organic phase was collected. The organic phase was washed with water (400.00 mL, 4.00 V) and saturated sodium chloride (400.00 mL, 4.00 V), respectively. After drying the organic phase with anhydrous sodium sulfate, it was concentrated to obtain a yellow liquid as the crude product. Hexane (500.00 mL, 5.00 V) was added to the crude product and stirred at 5-10℃ for 2.0 hours to produce 130.0 g of white solid, which was the product tris(phenylethynyl)-tert-butyltin, with a yield of 71.2% and an HPLC purity of 99.91%.

[0037] Figure 1 The 1H NMR spectrum data of the product tris(phenylethynyl)-tert-butyltin obtained in Example 1 are as follows: 1 H NMR (400MHz, Chloroform-d) δ 7.57 – 7.51 (m, 6H), 7.33 – 7.31 (m, 6H), 7.30 (m, 3H), 1.46 (s, 9H).

[0038] Mass spectrometry data for tert-butyltris(phenylethynyl)stanane: [M] = 480.0900, LC-MS (ESI): m / z = 503.0799 [M+Na] + .

[0039] Figure 2 This is the HPLC chromatogram of the product obtained in Example 1.

[0040] Example 2

[0041] The other conditions and procedures were the same as in Example 1, except that tetrahydrofuran was replaced with 2-methyltetrahydrofuran (19.8 g, 0.23 mol, 0.60 equiv.), and the amount of N-methylmorpholine was (4.2 mL, 0.038 mol, 0.10 equiv.). The final product yield was 66.8%, and the purity was 99.89%.

[0042] Comparative Example 1

[0043] Other conditions and procedures were the same as in Example 1, except that tetrahydrofuran was not added. The final product yield was 58.6% and the purity was 99.90%.

[0044] Comparative Example 2

[0045] The other conditions and procedures were the same as in Example 1, except that N-methylmorpholine was not added in step S2. The final product yield was 61.5% and the purity was 99.65%.

[0046] Comparative Example 3

[0047] The other conditions and procedures were the same as in Example 1, except that in step S2, N-methylmorpholine was replaced with an equimolar amount of LiCl. The final product yield was 64.2% and the purity was 99.85%.

Claims

1. A method for synthesizing tris(phenylethynyl)-tert-butyltin, characterized in that, Includes the following steps: (S1) Under an inert atmosphere, aromatic organic solvent, Lewis acid and organic amine, and phenylacetylene are mixed evenly to obtain mixture 1; (S2) Under an inert atmosphere and at 0-10℃, aromatic organic solvent, tin tetrachloride, tert-butylmagnesium chloride, ether solvent, and morpholine compound are mixed evenly. After the addition is complete, the mixture is stirred at 10-15℃ to obtain mixture 2. (S3) Under an inert atmosphere, at 10-15℃, mixture 2 is slowly added to mixture 1, and the reaction is maintained at this temperature. After the reaction is completed, post-processing is performed to obtain the product tris(phenylethynyl) tert-butyltin.

2. The synthesis method according to claim 1, characterized in that, In steps (S1) and (S2), the organic solvent is independently selected from at least one of toluene, xylene, and ethylbenzene.

3. The synthesis method according to claim 1, characterized in that, In step (S1), Lewis acid is selected from at least one of zinc chloride, aluminum trichloride, ferric chloride, boron trifluoride and its diethyl ether complex.

4. The synthesis method according to claim 1, characterized in that, In step (S1), the organic amine is selected from at least one of diethylamine, triethylamine, and pyridine.

5. The synthesis method according to claim 1, characterized in that, In step (S1), the molar ratio of Lewis acid, organic amine, and phenylacetylene is 0.6-0.8:1.2-1.5:

1.

6. The synthesis method according to claim 1, characterized in that, In step (S2), the molar ratio of tin tetrachloride to tert-butylmagnesium chloride is 1:1.3-1.7, for example, 1:1.5-1.

6.

7. The synthesis method according to claim 1, characterized in that, In step (S2), the molar ratio of tin tetrachloride, ether solvent, and morpholine compound is 1:0.5-0.8:0.1-0.

2.

8. The synthesis method according to claim 1, characterized in that, In step (S2), the ether solvent is selected from at least one of diethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran, and the morpholine compound is selected from at least one of N-methylmorpholine and 2,6-dimethylmorpholine.

9. The synthesis method according to claim 1, characterized in that, In step (S3), the amounts of mixture 1 and mixture 2 are such that the molar ratio of phenylacetylene in mixture 1 to tin tetrachloride in mixture 2 is 4-5:1; the reaction time is 8-15 h.

10. The synthesis method according to claim 1, characterized in that, In step (S3), the post-treatment involves filtering to obtain a filtrate and a filter cake. The filter cake is washed with an organic solvent, and the eluent and filtrate are combined. The organic phase is collected, washed with water and brine respectively, dried, and concentrated to obtain a crude product. The crude product is added to n-hexane and stirred at 5-10°C. A white solid precipitates out, which is the product tris(phenylethynyl)tert-butyltin.

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