Controllable synthesis method of polyisocyanide with polysilsesquioxane at one end

Abstract

The invention discloses a controllable synthesis method of polyisocyanide with polysilsesquioxane at one end, which comprises the following steps: (1) reacting 3-aminopropyl heptaisobutyl POSS (Polyhedral Oligomeric Silsesquioxane) and acetylenic acid under the action of an organic solvent and a catalyst, and washing and recrystallizing after the reaction is completed to prepare alkynyl-terminated heptaisobutyl POSS; (2) carrying out reaction on alkynyl-terminated heptaisobutyl POSS and a Pd (II) compound under the action of an organic solvent, an acid-binding agent and a catalyst, washing, extracting, drying and carrying out column chromatography to obtain a light yellow solid macroinitiator with alkyne-Pd (II) at the tail end; and (3) initiating polymerization of different isocyanide monomers in an organic solvent under a heating condition by using the macroinitiator with alkyne-Pd (II) at the tail end, and precipitating and centrifuging to obtain polyisocyanide with POSS at one end of a yellow product. The prepared polyisocyanide with POSS at one end is controllable in molecular weight, small in molecular weight distribution and good in stability.

Description

Technical Field

[0001] The present invention relates to the field of controllable synthesis of functional polymers and polymer self-assembly, and specifically relates to a method for controllable synthesis of polyisocyanide with polyhedral oligomeric silsesquioxane (POSS) at one end. Background Art

[0002] Helical structures widely exist in nature. Influenced by the helical structures of biological macromolecules, intensive studies on the synthesis of helical polymers have been carried out in recent decades. In this context, π-conjugated polyisocyanides have become one of the most studied helical polymers due to their interesting rod-like helical conformations and controllable living polymerization. Their unique rigid helical skeletons may exhibit interesting behaviors in aspects such as molecular self-assembly, circularly polarized luminescence, chiral recognition and catalysis, drug delivery and controlled release. Currently, polyisocyanides are usually prepared by the living polymerization of isocyanide monomers initiated by Pd(II) initiators, and well-defined helical polymers can be easily obtained.

[0003] Polyhedral oligomeric silsesquioxane (POSS) is a class of organic-inorganic hybrid materials with special structures, which are composed of polyhedral Si-O-Si bonds and several organic groups. In the past, most POSS-containing polymer hybrids were prepared by conventional chemical copolymerization, cross-linking or physical blending, and it was difficult to obtain hybrids with well-defined topological structures. In recent years, with the emergence of new living / controllable polymerization technologies, many new POSS hybrid polymers with good topological structures have been prepared, such as linear, star-shaped, ring-shaped, bottle-brush-shaped, etc. Currently, POSS-containing polymer organic-inorganic hybrid materials can be synthesized by controllable / living radical polymerization technologies, such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. However, there is no report on introducing POSS into polyisocyanides to achieve a linear topological structure capped with POSS. Moreover, pure polyisocyanide materials have limitations in terms of mechanical strength, thermal stability, compatibility, etc. Summary of the Invention

[0004] The object of the present invention is to provide a method for controllable synthesis of polyisocyanide with polyhedral oligomeric silsesquioxane (POSS) at one end, and the prepared POSS-capped polyisocyanide has controllable molecular weight and its distribution, stable thermodynamic properties, and good compatibility and self-assembly properties.

[0005] In one aspect of the present invention, a method for controllable synthesis of polyisocyanide with polyhedral oligomeric silsesquioxane (POSS) at one end is proposed. According to an embodiment of the present invention, the method includes the following steps:

[0006] (1) React 3-aminopropylheptaisobutyl POSS and alkynoic acid in an organic solvent under the action of a catalyst. After the reaction is completed, wash and recrystallize to obtain terminal alkynyl heptaisobutyl POSS;

[0007] The synthetic route of the above reaction is as follows:

[0008]

[0009] (2) Terminal alkynyl heptaisobutyl POSS reacts with Pd(II) compound under the action of an organic solvent, an acid-binding agent, and a catalyst. After washing, extraction, and drying, a macromolecular initiator with an alkyne-Pd(II) at the end is obtained by column chromatography as a pale yellow solid;

[0010] The synthetic route of the above reaction is as follows:

[0011]

[0012] (3) Using the macromolecular initiator with an alkyne-Pd(II) at the end to initiate the polymerization of different isocyanide monomers under the conditions of an organic solvent and heating. After precipitation and centrifugation, a polyisocyanide with POSS at one end is obtained as a yellow product.

[0013] The synthetic route of the above reaction is as follows:

[0014]

[0015]

[0016] In addition, according to the method for controllable synthesis of polyisocyanide with polyhedral oligomeric silsesquioxane at one end in the above embodiments of the present invention, the following additional technical features may also be included:

[0017] In some embodiments of the present invention, in step (1): the molar ratio of the 3-aminopropyl heptaisobutyl POSS to the alkynoic acid is 1:1 to 8; the catalyst is one of triethylamine, trimethylamine, diethylamine, dimethylamine, and pyridine; the solvent is one of tetrahydrofuran, dichloromethane, chloroform, and toluene.

[0018] In some embodiments of the present invention, in step (1): the reaction is carried out under a nitrogen atmosphere, the reaction temperature is room temperature, and the reaction time is 6 to 12 h; the washing is carried out by washing multiple times with a mixed solvent, then dissolving with a good solvent, and then adding a poor solvent for recrystallization.

[0019] In some embodiments of the present invention, the mixed solvent is a mixed solution of water and methanol, and the volume ratio of water to methanol is 1:3 to 12; the good solvent is one of dichloromethane, chloroform, tetrahydrofuran, and toluene; the poor solvent is one of methanol, ethanol, isopropanol, and petroleum ether.

[0020] In some embodiments of the present invention, in step (2): the molar ratio of the terminal alkynyl heptaisobutyl POSS to the Pd(II) compound is 1:1 to 5; the catalyst is cuprous chloride; the acid-binding agent is one of triethylamine, trimethylamine, diethylamine, dimethylamine, and pyridine; the organic solvent is one of dichloromethane, chloroform, tetrahydrofuran, and toluene.

[0021] In some embodiments of the present invention, in step (2), the Pd(II) compound is one of trans-bis(triethylphosphine)palladium(II) dichloride, bis(triphenylphosphine)palladium chloride, [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride, and bis(acetonitrile)palladium(II) chloride.

[0022] In some embodiments of the present invention, in step (2), the reaction is carried out under a nitrogen atmosphere, the reaction temperature is room temperature, and the reaction time is 3 to 8 h.

[0023] In some embodiments of the present invention, in step (3): the molar ratio of the macromolecular initiator with an alkynyl-Pd(II) at the end to the phenyl derivative isocyanide monomer is 1:10 to 500; the organic solvent used is one of chloroform, tetrahydrofuran, toluene, and chlorobenzene.

[0024] In some embodiments of the present invention, in step (3), the reaction temperature is 40 to 80 °C, the reaction time is 3 to 12 h; the precipitation used is a precipitating agent, and the precipitating agent is one of methanol, ethanol, isopropanol, acetonitrile, and acetone.

[0025] In some embodiments of the present invention, in step (3), the isocyanide monomer is one of phenylcarbodecaisocyanide, phenyl L-isocyanide, phenyl D-isocyanide, phenyl hydrophilic isocyanide, and pentafluorophenol isocyanide. The chemical formulas of the above five isocyanide monomers are as follows:

[0026]

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] In the present invention, a monofunctional POSS is prepared into a macromolecular initiator with an alkynyl-Pd(II) at the end, and the polymerization of the isocyanide monomer is initiated to obtain a polyisocyanide with a POSS at one end. The introduction of POSS can improve the performance of the polyisocyanide. By binding to the polymer chain, its unique nanostructure will cause microphase separation inside the material, improving the mechanical strength of the material. The high-temperature resistance of the siloxane backbone in POSS can increase the thermal decomposition temperature of the polyisocyanide material and improve the thermal stability of the material. At the same time, POSS has good solubility and crystallinity in organic solvents, enabling it to play an active role in fields such as polymer crystallization-driven self-assembly. Description of the Drawings

[0029] Figure 1 1H NMR spectrum of the alkyne-Pd(II) macroinitiator prepared in Example 1 of the present invention;

[0030] Figure 2 IR spectrum of the alkyne-Pd(II) macroinitiator prepared in Example 1 of the present invention;

[0031] Figure 3 Gel permeation chromatography of polycarbonyldecaisocyanide with POSS at one end in Example 3 of the present invention;

[0032] Figure 4 Circular dichroism spectrum of poly-L-isocyanide with POSS at one end in tetrahydrofuran in Example 4 of the present invention;

[0033] Figure 5 Atomic force microscopy image of self-assembly of polyhydrophilic isocyanide with POSS at one end in a tetrahydrofuran / water mixed system in Example 6 of the present invention;

[0034] Figure 6 1H NMR spectrum of polycarbonyldecaisocyanide with POSS at one end in Example 3 of the present invention. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Example 1

[0037] A method for preparing a macroinitiator with alkyne-Pd(II) includes the following steps:

[0038] (1) In a flask equipped with a magnetic stirrer, add 3-aminopropyl heptaisobutyl POSS (5 g, 5.73 mmol), alkynoic acid acyl chloride (2 g, 11.5 mmol), triethylamine (1.6 mL, 11.5 mmol), and tetrahydrofuran (40 mL). Replace the nitrogen in the flask three times using a suction pump, place it on a magnetic stirring table, and react the entire reaction system under a nitrogen atmosphere at room temperature for 12 h. Then stop the reaction, filter to remove the insoluble triethylamine hydrochloride, rotary evaporate the solvent under reduced pressure to obtain the crude product, and wash the crude product successively with water / methanol (v / v = 1 / 1, 100 mL), water / methanol (v / v = 1 / 4, 100 mL), and methanol (100 mL). Finally, dissolve it in an appropriate amount of ethyl acetate, add a large amount of petroleum ether to crystallize it, and filter to obtain terminal alkynyl isobutyl POSS. Dry the terminal alkynyl isobutyl POSS in a vacuum drying oven at 50 °C for 24 h to obtain 5.5 g of an off-white solid, with a yield of approximately 94.8%.

[0039] (2) Under a nitrogen atmosphere, add terminal alkynyl heptaisobutyl POSS (245.2 mg, 0.242 mmol), trans-bis(triethylphosphine)palladium(II) dichloride (100 mg, 0.242 mmol), copper(I) chloride catalyst (4 mg, 0.04 mmol), diethylamine (1 mL), and dichloromethane (10 mL) to a flask with a magnetic stir bar. Place it on a magnetic stirring table and react at room temperature for 5 h. Add deionized water to stop the reaction, separate the organic phase, wash it three times with water, extract the aqueous phase with dichloromethane to increase the yield, dry it with anhydrous sodium sulfate for 12 h, filter to remove the desiccant, perform column chromatography separation using a petroleum ether / ethyl acetate = 4 / 1 eluent after rotary evaporation, and vacuum dry it for 12 h after rotary evaporation to obtain a light yellow product, a macromolecular initiator with a terminal alkynyl-Pd(II). Weigh 316.3 mg of the light yellow solid, with a yield of approximately 94.0%.

[0040] Figure 1 is the 1H NMR spectrum of the macromolecular initiator with alkynyl-Pd(II) prepared in Example 1 of the present invention; Figure 2 is the infrared spectrum of the macromolecular initiator with alkynyl-Pd(II) prepared in Example 1 of the present invention, where a characteristic peak of the triple bond stretching vibration of the alkyne appears at a wave number of 2138.

[0041] Example 2

[0042] A method for preparing a macromolecular initiator with alkynyl-Pd(II), comprising the following steps:

[0043] (1) In a flask equipped with a magnetic stir bar, add 3-aminopropyl heptaisobutyl POSS (5 g, 5.73 mmol), alkynoic acid acyl chloride (2 g, 11.5 mmol), triethylamine (1.6 mL, 11.5 mmol), and dichloromethane (30 mL). Replace the nitrogen in the flask three times using a suction pump. Place it on a magnetic stirring table and react the entire reaction system under a nitrogen atmosphere at room temperature for 24 h. Then stop the reaction and rotary evaporate the solvent under reduced pressure to obtain the crude product. Wash the crude product three times with water / methanol (v / v = 1 / 4, 100 mL), and filter by suction to obtain terminal alkynyl isobutyl POSS. Dry the product in a vacuum drying oven at 60 °C for 12 h to obtain 5.3 g of an off-white solid, with a yield of approximately 91.4%.

[0044] (2) Under a nitrogen atmosphere, add terminal alkynyl heptaisobutyl POSS (245.2 mg, 0.242 mmol), trans-bis(triethylphosphine)palladium(II) dichloride (120 mg, 0.291 mmol), copper(I) chloride catalyst (3 mg, 0.03 mmol), triethylamine (0.1 mL), and dichloromethane (10 mL) to a flask equipped with a magnetic stir bar. Place it on a magnetic stirring table and react at room temperature for 3 h. Filter off the insoluble matter by suction and rotary evaporate. Perform column chromatography separation using a petroleum ether / ethyl acetate = 2 / 1 eluent. After rotary evaporation, dry in vacuo for 12 h to obtain a light yellow product, a macromolecular initiator with a terminal alkyne-Pd(II), weighing 321.8 mg of a light yellow solid, with a yield of approximately 95.8%.

[0045] Example 3

[0046] A method for the controllable synthesis of polyisocyanide with one end being polyhedral oligomeric silsesquioxane (POSS), comprising the following steps:

[0047] Put the alkyne-Pd(II) macromolecular initiator (2.4 mg, 0.0017 mmol) prepared in Example 1 and phenylcarbodecaisocyanide monomer (50 mg, 0.17 mmol) into a 10 mL polymerization flask equipped with a magnetic stir bar. Replace the reaction system with nitrogen using a double-tube system. Add 1 mL of tetrahydrofuran under a nitrogen atmosphere, seal it with silicone grease, and place it in an oil bath at 55 °C for 12 h. Then add a large amount of methanol to stop the reaction, and yellow solids precipitate. Centrifuge at 800 r / min for 3 min to obtain a yellow product, polycarbodecaisocyanide with one end being POSS; after vacuum drying, weigh 42 mg of yellow solid, with a yield of approximately 80.8%.

[0048] The chemical formula of the phenylcarbodecaisocyanide monomer is as follows:

[0049]

[0050] Figure 3It is the gel permeation chromatogram of polycarbonyldecaisocyanide with POSS at one end in Example 3 of the present invention. Its number average molecular weight is 29.68 kDa, and the molecular weight distribution is 1.12. It shows that the molecular weight and its distribution of the polymer are controllable. Figure 6 It is the proton nuclear magnetic resonance spectrum of polycarbonyldecaisocyanide with POSS at one end in Example 3 of the present invention.

[0051] Example 4

[0052] A controllable synthesis method of polyisocyanide with polyhedral oligomeric silsesquioxane (POSS) at one end, comprising the following steps:

[0053] Put the alkyne-Pd(II) macroinitiator (2.77 mg, 0.0020 mmol) prepared in Example 1 and phenyl L-type isocyanide monomer (50 mg, 0.14 mmol) into a 10 mL polymerization bottle with a magnetic stirrer. The reaction system is replaced with nitrogen by a double-row tube. Under nitrogen flow, 1 mL of chloroform is added. After coating with silicone grease and sealing, it is placed in an oil bath at 55 °C and reacted for 12 h. Then, a large amount of methanol is added to stop the reaction, and a yellow solid precipitates. After centrifugation at 800 r / min for 3 min by a centrifuge, a yellow product, poly L-type isocyanide with POSS at one end, is obtained; after drying in vacuum at room temperature, 38 mg of yellow solid is weighed, and the yield is about 73.1%.

[0054] The chemical formula of the phenyl L-type isocyanide monomer is as follows:

[0055]

[0056] Figure 4 It is the circular dichroism spectrum of poly L-type isocyanide with POSS at one end in Example 4 of the present invention. It shows an obvious ultraviolet absorption peak at a wavelength of 365 nm, which is the characteristic absorption of the carbon-nitrogen double bond in the polyisocyanide main chain, and corresponds to a negative CD absorption peak, indicating that POSS poly L-type isocyanide forms a left-handed helix.

[0057] Example 5

[0058] A controllable synthesis method of polyisocyanide with polyhedral oligomeric silsesquioxane (POSS) at one end, comprising the following steps:

[0059] The alkyne-Pd(II) macroinitiator prepared in Example 1 (2.33 mg, 0.0017 mmol) and phenyl D-isocyanide monomer (60 mg, 0.168 mmol) were placed in a 10 mL polymerization flask equipped with a magnetic stir bar. The reaction system was purged with nitrogen using a double-tube system. Under a nitrogen atmosphere, 1 mL of chloroform was added. After sealing with silicone grease, the flask was placed in an oil bath at 55 °C and reacted for 12 h. Subsequently, a large amount of methanol was added to stop the reaction, and a yellow solid precipitated. The yellow product, poly D-isocyanide with POSS at one end, was obtained by centrifugation at 800 r / min for 3 min. After vacuum drying, 56 mg of yellow solid was obtained, and the yield was approximately 90.3%.

[0060] The chemical formula of the phenyl D-isocyanide monomer is as follows:

[0061]

[0062] Example 6

[0063] A method for the controllable synthesis of polyisocyanide with polyhedral oligomeric silsesquioxane (POSS) at one end, comprising the following steps:

[0064] The alkyne-Pd(II) macroinitiator prepared in Example 1 (4.12 mg, 0.0030 mmol) and phenyl hydrophilic isocyanide monomer (100 mg, 0.296 mmol) were placed in a 10 mL polymerization flask equipped with a magnetic stir bar. The reaction system was purged with nitrogen using a double-tube system. Under a nitrogen atmosphere, 1.5 mL of tetrahydrofuran was added. After sealing with silicone grease, the flask was placed in an oil bath at 55 °C and reacted for 12 h. Subsequently, a large amount of diethyl ether was added to stop the reaction, and a yellow solid precipitated. The yellow product, polyhydrophilic isocyanide with POSS at one end, was obtained by centrifugation at 800 r / min for 3 min. After vacuum drying, 62.8 mg of yellow solid was obtained, and the yield was approximately 60.4%.

[0065] The chemical formula of the phenyl hydrophilic isocyanide monomer is as follows:

[0066]

[0067] Figure 5 This is an atomic force microscopy image of the self-assembly of polyhydrophilic isocyanide with POSS at one end in a tetrahydrofuran / water mixed system in Example 6 of the present invention, showing spherical micelles with a size of about 200 nm. Since POSS is non-polar and hydrophobic, and the side chain of polyhydrophilic isocyanide is polar and hydrophilic. Polyhydrophilic isocyanide with POSS at one end can dissolve in the good solvent tetrahydrofuran. After adding water, the POSS segments crystallize and aggregate together to form spherical micelles.

[0068] Example 7

[0069] A controllable synthesis method of polyisocyanide with one end being polyhedral oligomeric silsesquioxane (POSS), comprising the following steps:

[0070] Put the alkyne-Pd(II) macroinitiator (3.16 mg, 0.00227 mmol) prepared in Example 2 and pentafluorophenol isocyanide monomer (71 mg, 0.227 mmol) into a 10 mL polymerization flask with a magnetic stirrer. The reaction system is purged with nitrogen three times using a double-tube. Under nitrogen atmosphere, 1.5 mL of chloroform is injected with a syringe. After applying silicone grease and sealing, it is placed in an oil bath at 55 °C and reacted for 12 h. Then, a large amount of methanol is added to stop the reaction, and a yellow solid precipitates. After centrifugation at 8000 r / min for 3 min using a centrifuge, a yellow product, poly(pentafluorophenol isocyanide) with one end being POSS, is obtained. After vacuum drying, 63 mg of yellow solid is weighed, and the yield is about 85.1%.

[0071] The chemical formula of the pentafluorophenol isocyanide monomer is as follows:

[0072]

[0073] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the structure of the present invention or exceed the scope defined by this claim book, they shall fall within the protection scope of the present invention.

Claims

1. A controllable synthesis method of polyisocyanate with polysilsesquioxane at one end, characterized in that: The following steps are involved: (1) 3-aminopropyl heptaisobutyl POSS and acetylenic acid react in the presence of an organic solvent and a catalyst, and after the reaction is completed, the acetylenic terminal heptaisobutyl POSS is prepared by washing and recrystallization; (2) The terminal alkynyl heptaisobutyl POSS reacts with a Pd(II) compound in the presence of an organic solvent, an acid-binding agent, and a catalyst, and after washing, extraction, drying, and column chromatography, a light yellow solid macromolecular initiator with an alkyne-Pd(II) terminal is obtained; (3) A macromolecular initiator with an alkyne-Pd(II) at the end is used to initiate the polymerization of different isonitrile monomers in an organic solvent under heating conditions. After precipitation and centrifugation, a yellow product with POSS at one end is obtained.

2. The controllable synthesis method of polyisocyanide having polysilsesquioxane at one end according to claim 1, characterized in that: In step (1): The molar ratio of the 3-aminopropyl heptaisobutyl POSS to acetylenic acid is 1:1-8; The catalyst is one of triethylamine, trimethylamine, diethylamine, dimethylamine and pyridine; The solvent is one of tetrahydrofuran, dichloromethane, chloroform and toluene.

3. The controllable synthesis method of polyisocyanide having polysilsesquioxane at one end according to claim 1, characterized in that: In step (1): The reaction is carried out under a nitrogen atmosphere, at room temperature, and for 6 to 12 hours; The washing is performed by washing with a mixed solvent for multiple times, then dissolving with a good solvent, and then adding a poor solvent for recrystallization.

4. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 3, characterized in that: The mixed solvent is a mixed solution of water and methanol, and the volume ratio of water to methanol is 1:3-12; the good solvent is one of dichloromethane, chloroform, tetrahydrofuran, and toluene; the poor solvent is one of methanol, ethanol, isopropanol, and petroleum ether.

5. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 1, characterized in that: In step (2): The molar ratio of the terminal alkynyl heptaisobutyl POSS to the Pd(II) compound is 1:1-5; The catalyst is cuprous chloride; The acid binding agent is one of triethylamine, trimethylamine, diethylamine, dimethylamine and pyridine; The organic solvent is one of dichloromethane, chloroform, tetrahydrofuran and toluene.

6. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 1, characterized in that: In step (2), the Pd(II) compound is one of trans-bis(triethylphosphine)palladium(II) dichloride, bis(triphenylphosphine)palladium chloride, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride, and bis(acetonitrile)palladium(II) chloride.

7. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 1, characterized in that: In step (2), the reaction is carried out under a nitrogen atmosphere, the reaction temperature is room temperature, and the reaction time is 3 to 8 hours.

8. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 1, characterized in that: In step (3): The molar ratio of the macroinitiator with alkyne-Pd(II) at the end to the phenyl derivative isonitrile monomer is 1:10-500; The organic solvent used is one of chloroform, tetrahydrofuran, toluene and chlorobenzene.

9. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 2, characterized in that: In step (3), the reaction temperature is 40-80° C., and the reaction time is 3-12 h. The precipitation is carried out using a precipitant, which is one of methanol, ethanol, isopropanol, acetonitrile, and acetone.

10. The controllable synthesis method of polyisocyanide with polysilsesquioxane at one end according to claim 2, characterized in that: In step (3), the isonitrile monomer is one of phenyl carbonyl isonitrile, phenyl L-type isonitrile, phenyl D-type isonitrile, phenyl hydrophilic isonitrile and pentafluorophenol isonitrile.

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