A method for preparing a dimer-mediated organic polymer single crystal

Abstract

The present application relates to a kind of preparation method of dimer-mediated organic polymer single crystal, belong to organic polymer single crystal technical field.The preparation method of the present application includes the following steps: S1, metal salt, alkenyl pyridine ligand and auxiliary ligand are carried out coordination self-assembly in solvent, and coordination polymer single crystal reaction template is obtained by washing and drying;S2, under the irradiation of ultraviolet light or visible light, coordination polymer single crystal reaction template carries out [2+2] photo-cycloaddition, and the coordination polymer containing cyclobutane dimer is obtained;S3, under the action of lye or acid liquor, the coordination polymer containing cyclobutane dimer is dissociated, and dimer single crystal is obtained by extraction, concentration, recrystallization;S4, under the irradiation of ultraviolet light or visible light, dimer single crystal carries out topological chemistry polymerization reaction, and organic polymer single crystal is obtained;From alkenyl pyridine ligand to high-quality polymer single crystal with self-supporting long-range ordered structure, precision controllable preparation is successfully realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic polymer single crystals, and particularly relates to a preparation method of organic polymer single crystals mediated by dimers. BACKGROUND

[0002] Organic polymer single crystals can maximize the inherent physical and chemical properties of polymers, such as high charge transfer efficiency, excellent mechanical strength and toughness, and unique optical properties such as light absorption and light emission, due to the highly regular long-range ordered arrangement of molecular chains in three-dimensional space. Based on these excellent properties, organic polymer single crystals have shown irreplaceable application value and great development potential in a series of frontier electronic information fields such as field effect transistors, high-efficiency solar cells, high-sensitivity photodetectors, and flexible electronic devices. Therefore, developing efficient organic polymer single crystal preparation technology has a crucial supporting role and important practical significance for breaking through the inherent performance bottlenecks of traditional amorphous or semi-crystalline polymer materials and promoting the research and development process and industrial application of the next generation of high-performance organic electronic devices.

[0003] However, polymer molecules themselves have inherent characteristics of long chain length and variable conformation, and molecular chain entanglement and disordered stacking phenomena easily occur during polymerization and crystallization, which makes it difficult to prepare organic polymer single crystals with macroscopic size, low defect density, and perfect crystal structure.

[0004] As of now, the mainstream organic polymer single crystal preparation strategies in the industry mainly include solution method, melting method, and solid-phase topological polymerization method. Among them, the preparation process of solution method and melting method is limited by the ordered degree of monomer molecular arrangement in the crystallization stage, and at the same time faces the contradiction between the molecular chain growth rate and the chain entanglement phenomenon in the polymerization process, which makes it difficult to prepare large-size, high-structural integrity polymer single crystal materials using these two methods. Although the solid-phase topological polymerization method can realize the direct conversion from ordered monomers to ordered polymer structures, it has certain advantages in crystal structure inheritance, but it puts forward extremely strict requirements for the solid-state pre-assembly structure of monomers; this method strictly depends on the formation of precise ordered pre-assembly arrays of monomers in the solid state, and must accurately match the spatial geometric conditions required by topological chemical reactions (such as [2+2] photocycloaddition reaction), including key parameters such as the distance between reactive groups, relative orientation, etc. This stringent requirement makes most monomers with potential functions excluded from the applicable scope due to their inability to meet the spatial geometric matching conditions, severely limiting the large-scale application of the solid-phase topological polymerization method.

[0005] To broaden the scope of monomers that can be used to prepare polymer single crystals, researchers have developed new preparation strategies such as co-crystal template method and coordination template method in recent years. These methods induce monomers to form ordered arrangement through the induction of templates, and then carry out solid-state polymerization, which to some extent alleviates the problem of insufficient self-assembly ability of monomers. However, there is a fundamental defect in this method: the ordered structure of the prepared polymer is highly dependent on the spatial constraint provided by the template during the formation process; when the template is removed after the reaction is completed, the long-range ordered structure of the polymer is difficult to maintain independently, and the crystal structure will generally collapse and lose order, which will cause the excellent functional performance of the polymer to decline significantly or even completely lost. This problem greatly restricts the application of polymer single crystal materials prepared by template-induced method in actual electronic devices.

[0006] Therefore, it is urgent to develop a new method that can prepare high-quality organic polymer single crystals without relying on templates. SUMMARY

[0007] Therefore, the technical problem to be solved by the present application is to overcome the problems of narrow applicability of solid-phase topological polymerization monomers and dependence of product structure stability on external templates in the prior art.

[0008] To solve the above technical problems, the present application provides a method for preparing organic polymer single crystals mediated by dimers, which utilizes the directional regulation of coordination polymer single crystal reaction templates to precisely pre-organize alkenyl pyridine ligands and convert them into coordination polymers containing cyclobutane dimers through [2+2] photocycloaddition reaction; after the template is dissociated, the dimmer single crystal is obtained by extraction, concentration and recrystallization; using the dimmer single crystal as a self-supporting precursor, the precise and controllable preparation of high-quality organic polymer single crystals with self-supporting long-range ordered structure from alkenyl pyridine ligands can be realized, and this method has the outstanding advantages of simple steps, mild conditions, stable yield and high crystallinity of the product.

[0009] The purpose of the present application is to provide a method for preparing organic polymer single crystals mediated by dimers, comprising the following steps:

[0010] S1, a metal salt, an alkenyl pyridine ligand and an auxiliary ligand are subjected to coordination self-assembly in a solvent to obtain a coordination polymer single crystal reaction template through washing and drying; the alkenyl pyridine ligand has a structural formula of R is selected from substituted or unsubstituted phenyl, naphthyl or anthracene; the substituted group is fluorine, chlorine, hydroxyl, methyl or methoxy; the alkenyl pyridine ligand cannot meet the spatial geometric conditions of [2+2] photocycloaddition in a solid state because the distance between olefin double bonds does not meet the requirements and the molecules are not arranged in head-to-tail parallel; and in the structure of the coordination polymer single crystal reaction template prepared by the alkenyl pyridine ligand, the ligand is arranged in head-to-tail orientation, the olefin double bonds are parallel to each other and the distance is in a suitable interval of 3.5 Å-4.2 Å.

[0011] S2, under irradiation of ultraviolet light or visible light, the coordination polymer single crystal reaction template in S1 is subjected to [2+2] photocycloaddition reaction to obtain a coordination polymer containing cyclobutane dimers;

[0012] S3, under the action of lye or acid, the coordination polymer containing cyclobutane dimers in S2 is subjected to dissociation, and then the dimmer single crystal is obtained through extraction, concentration and recrystallization;

[0013] S4, under irradiation of ultraviolet light or visible light, the dimmer single crystal in S3 is subjected to topological chemical polymerization reaction to obtain the organic polymer single crystal.

[0014] In an embodiment of the present application, in S1, the metal salt is selected from cadmium salt and / or manganese salt;

[0015] And / or, the auxiliary ligand is selected from one or more of isophthalic acid, p-chlorobenzoic acid, p-bromobenzoic acid, 5-chloroisophthalic acid, 5-bromoisophthalic acid and 4,4'-diphenyl ether dicarboxylic acid.

[0016] In an embodiment of the present application, the cadmium salt is selected from one or more of cadmium nitrate, cadmium chloride and cadmium sulfate;

[0017] And / or, the manganese salt is manganese nitrate.

[0018] In an embodiment of the present application, in S1, the molar ratio of the metal salt, the alkenyl pyridine ligand and the auxiliary ligand is 1:(0.8-1.2):(0.8-1.2).

[0019] In an embodiment of the present application, in S1, the temperature of the coordination self-assembly is 110-180 ℃, and the time is 8-48 h.

[0020] In an embodiment of the present application, in S2, the power of the irradiation is 10-30 W, and the time is 0.5-5.0 h.

[0021] In one embodiment of the present application, in S2, the [2+2] photocycloaddition reaction selectively occurs between layers.

[0022] In one embodiment of the present application, in S3, the alkali solution is a sodium hydroxide solution.

[0023] And / or, the acid solution is selected from a nitric acid solution or a hydrochloric acid solution.

[0024] And / or, the concentration of the alkali solution and the acid solution is independently 0.5 mol / L-1.5 mol / L.

[0025] In one embodiment of the present application, in S3, the solvent used for extraction is selected from dichloromethane or trichloromethane.

[0026] In one embodiment of the present application, in S3, the solvent system for recrystallization is a mixed solvent of dichloromethane and petroleum ether.

[0027] In one embodiment of the present application, in S4, the power of the irradiation is 90W-110W, and the time is 18h-36h.

[0028] The technical solution of the present application has the following advantages compared with the prior art:

[0029] (1) The preparation method of the present application constructs a coordination polymer single crystal reaction template with a clear structure by coordinating self-assembly of an alkenyl pyridine ligand with a metal salt and an auxiliary ligand; the template serves as a directional molecular pre-organization platform, and with the help of the space orientation ability of coordination bonds, the alkenyl pyridine ligand, which originally has a double bond spacing that does not meet the requirements in solid state, a head-tail parallel arrangement of molecules, and cannot meet the spatial geometric conditions of [2+2] photocycloaddition, is forced to arrange into an ideal stacking configuration with head-tail orientation, parallel double bonds and a suitable interval, and then efficiently and in situ undergoes [2+2] photocycloaddition under ultraviolet or visible light irradiation, to convert into a coordination polymer containing a cyclobutane dimer; the coordination polymer containing a cyclobutane dimer is dissociated, extracted, concentrated and recrystallized to obtain a dimer single crystal, which serves as a rigid building unit with a clear configuration, and spontaneously assembles into a regular stacking structure that meets the requirements of topological polymerization, with its fixed three-dimensional shape, enhanced π-π stacking effect and optimized molecular symmetry; this transformation from "flexible ligand" to "rigid structure unit" is the key mechanism to realize intrinsic ordered polymerization independent of exogenous templates, thereby breaking the limitation of monomer crystallization behavior on the polymerization path and significantly widening the monomer application range of organic polymer single crystals.

[0030] (2) The preparation method of the application takes a dimer single crystal as a stable structure intermediate, which is obtained by [2+2] photocycloaddition reaction in a coordination polymer single crystal reaction template, and the cyclobutane core constitutes a rigid segment of a future polymer main chain; after the template is dissolved under mild conditions of alkaline solution or acid solution, the free dimer single crystal can still completely retain the original stereochemical structure, and with the determined molecular shape, enhanced pi-pi stacking effect and optimized molecular symmetry, it self-assembles to form a thermodynamically stable stacking structure (the key olefin bond is arranged in parallel and the distance meets the requirement of solid phase [2+2] photocycloaddition topological polymerization) in the recrystallization process; then intrinsic polymerization is realized under ultraviolet light or visible light irradiation without external template, and the long-range ordered structure stability is guaranteed by the polymer chain itself; the method realizes the transformation from "template constrained state" to "intrinsic ordered state" through "functional phasedecoupling", that is, the template stage is responsible for ligand directional arrangement and accurate preparation of dimer single crystal, and the subsequent stage is completed by the dimer single crystal itself to realize ordered stacking and polymerization, which fundamentally overcomes the core problem of polymer structure collapse and loss of order after template removal in the traditional template method.

[0031] (3) The preparation method of the application adopts a complete process chain of "coordination assembly-photodimerization-template dissociation-crystal reconstruction-topological polymerization", and the core advantage lies in that the intermediate products (coordination polymer single crystal reaction template, coordination polymer containing cyclobutane dimer, and dimer single crystal) of each step are in single crystal form, and absolute structure confirmation and full-process quality monitoring can be realized through X-ray diffraction technology, so that the structural accuracy and batch consistency of the final organic polymer single crystal are ensured from the source; the method has mild reaction conditions, high raw material utilization rate, and excellent product crystallinity, and has significant process stability, which lays a solid foundation for the practical industrial application of organic polymer single crystals. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments of the application and in conjunction with the drawings, in which:

[0033] Figure 1 is a nuclear magnetic hydrogen spectrum (1H NMR) graph of 1,5-bpvn of the application;

[0034] Figure 2 is a nuclear magnetic carbon spectrum (13C NMR) graph of 1,5-bpvn of the application;

[0035] Figure 3 is a Cd(II) center coordination environment graph (hexa-coordination) of [Cd(1,5-bpvn)(IPA)]n in Example 1 of the application;

[0036] Figure 4Schematic diagram of two-dimensional double layer structure of [Cd(l,5-bpvn)(IPA)]n in Example 1 of the present application;

[0037] Figure 5 Schematic diagram of monomer arrangement of [Cd(l,5-bpvn)(IPA)]n in Example 1 of the present application;

[0038] Figure 6 Structure diagram of [Cd(rctt-pncd)0.5(IPA)]n in Example 1 of the present application;

[0039] Figure 7 Molecular structure diagram of rctt-pncd in Example 1 of the present application;

[0040] Figure 8 Solid-state molecular packing diagram of rctt-pncd in Example 1 of the present application;

[0041] Figure 9 Structure diagram of poly-dpcn in Example 1 of the present application;

[0042] Figure 10 Coordination environment diagram (four-coordination) of Zn(II) center of [Zn(l,5-bpvn)(TPA)]n in Comparative Example 1 of the present application;

[0043] Figure 11 Schematic diagram of monomer arrangement of [Zn(l,5-bpvn)(TPA)]n in Comparative Example 1 of the present application;

[0044] Figure 12 Structure diagram of [Znn(poly-dpcn)(TPA)n] in Comparative Example 1 of the present application;

[0045] Figure 13 NMR hydrogen spectrum diagram of poly-dpcn in Comparative Example 1 of the present application;

[0046] Figure 14 Powder X-ray diffraction (PXRD) diagram of poly-dpcn in Comparative Example 1 of the present application;

[0047] Figure 15 Coordination environment diagram (seven-coordination) of Cd(II) center of [Cd(l,5-bpvn)(TPA)0.5(NO3)]n in Comparative Example 2 of the present application;

[0048] Figure 16 Schematic diagram of two-dimensional double layer structure of [Cd(l,5-bpvn)(TPA)0.5(NO3)]n in Comparative Example 2 of the present application;

[0049] Figure 17Schematic diagram of monomer arrangement of [Cd(l,5-bpvn)(TPA)0.5(NO3)]n in Inventive Comparative Example 2 of the present application;

[0050] Figure 18 Solid state molecular packing diagram of 1,5-bpvn crystal in Test Example 1 of the present application;

[0051] Figure 19 PXRD diagrams of 1,5-bpvn crystal before and after light irradiation in Test Example 1 of the present application;

[0052] Figure 20 1H NMR diagram of [Cd(l,5-bpvn)(IPA)]n in Test Example 2 of the present application;

[0053] Figure 21 1H NMR diagram of [Cd(rctt-pncd)0.5(IPA)]n in Test Example 2 of the present application;

[0054] Figure 22 IR diagram of [Cd(l,5-bpvn)(IPA)]n in Test Example 2 of the present application;

[0055] Figure 23 IR diagram of [Cd(rctt-pncd)0.5(IPA)]n in Test Example 2 of the present application;

[0056] Figure 24 PXRD diagram of [Cd(l,5-bpvn)(IPA)]n in Test Example 2 of the present application;

[0057] Figure 25 PXRD diagram of [Cd(rctt-pncd)0.5(IPA)]n in Test Example 2 of the present application;

[0058] Figure 26 1H NMR diagram of rctt-pncd in Test Example 3 of the present application;

[0059] Figure 27 1H NMR diagram of poly-dpcn in Test Example 3 of the present application;

[0060] Figure 28 13C CPMAS NMR diagram of rctt-pncd single crystal powder and poly-dpcn single crystal powder in Test Example 3 of the present application;

[0061] Figure 29A high resolution electrospray mass spectrum (HR-ESI-MS) of rctt-pncd in Test Example 3 of the present application;

[0062] Figure 30 A matrix assisted laser desorption ionization time of flight mass spectrum (MALDI-TOF MS) of the soluble fraction of poly-dpcn in Test Example 3 of the present application;

[0063] Figure 31 An infrared spectrum (IR) of rctt-pncd in Test Example 3 of the present application;

[0064] Figure 32 An infrared spectrum (IR) of poly-dpcn in Test Example 3 of the present application;

[0065] Figure 33 An experimental and simulated powder X-ray diffraction (PXRD) pattern of rctt-pncd in Test Example 3 of the present application;

[0066] Figure 34 An experimental and simulated powder X-ray diffraction (PXRD) pattern of poly-dpcn in Test Example 3 of the present application. DETAILED DESCRIPTION

[0067] The present application will be further described with reference to the following examples and figures, which are intended to be illustrative only and are not intended to limit the scope of the present application.

[0068] In the present application, unless otherwise specified, the preparation of 1,5-bpvn includes the following steps: 1,5-dibromonaphthalene (2.86 g, 10 mmol), anhydrous potassium carbonate (2.49 g, 18 mmol), bis(triphenylphosphine)palladium dichloride (0.35 g, 0.50 mmol) and 4-vinylpyridine (2.80 mL, 22 mmol) are sequentially added into a 100 mL round-bottom flask, and 50 mL of N,N-dimethylformamide (DMF) is injected as a solvent; then the reaction device is connected to a nitrogen balloon, and the system is fully replaced with nitrogen by three cycles of vacuum-nitrogen refilling to ensure nitrogen protection throughout the process. The flask is then placed in an oil bath preheated to 120°C, and the reaction is carried out under nitrogen atmosphere with strong stirring at a speed of 1000 rpm for 72 h. After the reaction is completed, the nitrogen protection is maintained, a vacuum device is connected, and the pressure is slowly reduced. The solvent is removed by distillation under reduced pressure at about 80°C. When there is no solvent flowing out of the system and a solid or high-viscosity residue is formed, the distillation is stopped and cooled to room temperature. Then the residual solid is dispersed in water, and the mixture is subjected to liquid-liquid extraction with dichloromethane (3 x 50 mL). After the layers are separated, the lower dichloromethane layer is collected and the organic layers obtained by three extractions are combined. The combined organic phase is dried with anhydrous sodium sulfate, filtered to remove the drying agent after standing at room temperature for 30 min, and the filtrate is transferred to a rotary evaporation flask. The dichloromethane is removed by rotary evaporation under reduced pressure at a water bath temperature of 45°C. A brown-yellow crude product powder is obtained. Finally, the crude product is saturatedly dissolved in dichloromethane, excess petroleum ether is added for recrystallization, and the solid is collected by suction filtration after standing for 10 min. The target product 1,5-bpvn in the form of a bright yellow powder is obtained by vacuum drying, with a yield of 2.08 g and a yield of 62% (Example 1). Figures 1-2 ).

[0069] Example 1

[0070] The method for preparing a dimer-mediated organic polymer single crystal according to the present embodiment specifically includes the following steps:

[0071] S1, Preparation of coordination polymer single crystal reaction template [Cd(l,5-bpvn)(IPA)]n: Under room temperature, accurately weigh cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O, 3.08 mg, 0.01 mmol), 1,5-bpvn (3.34 mg, 0.01 mmol) and isophthalic acid (H2IPA, 1.66 mg, 0.01 mmol) in a molar ratio of 1:1:1, and place them in a 5 mL thick-walled pressure tube, then add 0.4 mL of N,N-dimethylformamide (DMF) and 1.2 mL of water, seal and ultrasonic dispersion for 3 min; place the pressure tube in a programmed oven, react at 130°C for 24 h, then cool to 20°C at a rate of 20°C / h, orange block crystals are precipitated in the system, filter and wash with absolute ethanol, and dry naturally in air to obtain the coordination polymer single crystal reaction template [Cd(l,5-bpvn)(IPA)]n, with a yield of 5.25 mg and a yield of 86%, and the structure and monomer arrangement characteristics thereof are as shown in Figures 3-5 ; wherein the coordination environment of the Cd(II) central metal ion in the coordination polymer is as shown in Figure 3 ; the overall structure takes the Cd2(IPA)2 one-dimensional chain as a secondary building unit, which is further connected by 1,5-bpvn bridging ligands, and finally forms a two-dimensional double-layer structure as shown in Figure 4 ; and the specific arrangement mode of the 1,5-bpvn monomer is as shown in Figure 5 , and the key structural characteristics thereof include: (i) in the two-dimensional layer, the monomers are arranged face-to-face, and the two groups of olefin bonds are parallel to each other with a distance of 3.83 Å; (ii) between adjacent two-dimensional layers, the monomers are arranged in a head-to-tail orientation, and one group of olefin bonds is parallel with a distance of 3.67 Å, which provides a basis for the occurrence of subsequent photodimerization reaction.

[0072] S2, Preparation of coordination polymer [Cd(rctt-pncd)0.5(IPA)]n containing cyclobutane dimers: Take an appropriate amount of coordination polymer single crystal reaction template [Cd(l,5-bpvn)(IPA)]n and place it on a clean glass slide, and irradiate it with natural white light with a vertical distance of 10 cm and a power of 20 W for 1 h to induce a single crystal-single crystal photodimerization reaction between layers, and after the reaction is completed, the [2+2] photocycloaddition product, i.e. the coordination polymer [Cd(rctt-pncd)0.5(IPA)]n containing cyclobutane dimers, is obtained with a conversion rate of 95%, and the three-dimensional network structure thereof is as shown in Figure 6 , which is connected by cyclobutane units with rctt configuration.

[0073] S3, Preparation of dimer single crystal rctt-pncd: 450 mg of coordination polymer containing cyclobutane dimer [Cd(rctt-pncd)0.5(IPA)]n was weighed into a 50 mL flask, 15 mL of 1 mol / L NaOH solution was added, and the coordination framework was completely dissociated by stirring at room temperature for 3 h. Then the system was extracted with dichloromethane (3 x 20 mL) for several times, the organic phases were combined and dried over anhydrous sodium sulfate, and the dried filtrate was concentrated by rotary evaporation under reduced pressure. The obtained solid was slowly recrystallized (solvent system: dichloromethane: petroleum ether = 1.0:3.0 (v / v)) to obtain dimer single crystal rctt-pncd with a yield of 82.1%; its single crystal structure is shown in Figure 7 , and there is significant two-component positional disorder in its structure; the solid-state molecular packing is shown in Figure 8 , and the dimer is arranged in head-to-tail orientation in the single crystal, in which the key olefinic bonds are arranged in parallel with a distance of 3.62 Å, meeting the requirements of solid-phase [2+2] photocycloaddition topological polymerization reaction.

[0074] S4, Preparation of organic polymer single crystal poly-dpcn: The dimer single crystal rctt-pncd was irradiated under 100 W natural white light for 24 h to induce solid-phase polymerization reaction, obtaining organic polymer single crystal poly-dpcn, i.e. poly[1-(2,4-diphenylcyclobutyl)naphthalene]; its structure is shown in Figure 9 (diffraction data shows that its resolution reaches 0.70 Å).

[0075] Comparative Example 1

[0076] S1, Preparation of coordination polymer single crystal reaction template [Zn(1,5-bpvn)(TPA)]n: basically the same as S1 of Example 1, except that cadmium nitrate tetrahydrate was replaced by zinc nitrate hexahydrate, and isophthalic acid was replaced by terephthalic acid (H2TPA); obtaining coordination polymer single crystal reaction template [Zn(1,5-bpvn)(TPA)]n with a yield of 5.64 mg and a yield of 93%, and its structure and monomer arrangement characteristics are shown in Figures 10-11 , the coordination environment of Zn(II) center metal ion in the structure is shown in Figure 10 , and the 1,5-bpvn monomer in the structure is arranged in continuous head-to-tail arrangement Figure 11 , and its olefinic double bonds are parallel to each other with a distance of 3.86 Å, meeting the geometric conditions required for topological polymerization, which also indicates that the template structure can directly support photopolymerization reaction in the coordination framework, and then generate organic polymer.

[0077] S2, Preparation of coordination polymer [Znn(poly-dpcn)(TPA)n]: same as S2 of Example 1, to obtain coordination polymer [Znn(poly-dpcn)(TPA)n] with structure as shown in Figure 12 which has transformed from the three-dimensional six-fold interpenetrated network of the starting material [Zn(l,5-bpvn)(TPA)]n to a non-interpenetrated framework, with the organic polymer chains generated in the reaction integrated into the coordination framework as structural units and forming stable strong coupling with the metal-assisted ligand network.

[0078] S3, Preparation of organic polymer poly-dpcn: same as S3 of Example 1, to obtain organic polymer poly-dpcn; its nuclear magnetic resonance hydrogen spectrum as shown in Figure 13 which confirms the successful preparation of the organic polymer; the powder X-ray diffraction (PXRD) pattern as shown in Figure 14 which shows no characteristic diffraction peaks of crystalline material, indicating that after removal of the template, the long-range ordered structure of the polymer that could be maintained under the spatial constraints of the coordination template has lost its self-supporting ability, resulting in the final product transforming into an amorphous polymer. This is because the poly-dpcn has lost the geometric constraints and template provided by the coordination framework, and has restored its intrinsic high-entropy, flexible, high-degree-of-freedom conformation, which cannot maintain long-range order without external constraints.

[0079] Comparative Example 2

[0080] Preparation of coordination polymer single crystal reaction template [Cd(l,5-bpvn)(TPA)0.5(NO3)]n: basically same as S1 of Example 1, except that isophthalic acid is replaced by terephthalic acid; to obtain coordination polymer single crystal reaction template [Cd(l,5-bpvn)(TPA)0.5(NO3)]n, with its structure and monomer arrangement characteristics as shown in Figures 15-17The nitrate ions from the cadmium nitrate tetrahydrate participate in the coordination of the Cd(II) center, and ultimately form a two-dimensional double-layer structure, with an olefin bond distance of 4.15 Å within the layer; the 1,5-bpvn monomers between adjacent two-dimensional layers are arranged head-to-tail, but the olefin double bonds are staggered, with an average distance of 5.04 Å, which is fundamentally different from the monomer arrangement of the template in Example 1. This is because isophthalic acid (IPA) and terephthalic acid (H2TPA) have the same molecular formula, but the two carboxyl groups are located at the meta and para positions on the benzene ring, respectively, resulting in completely different coordination geometries and spatial extension directions; in addition, the participation of nitrate ions further changes the overall framework construction method, ultimately making the interlayer olefin bond distance and arrangement of this template unable to meet the interlayer selectivity requirements of the [2+2] photocycloaddition reaction, and unable to achieve the expected dimerization reaction to generate a cyclobutane-based dimer single crystal molecule. The results show that the molecular structure difference of the auxiliary ligand can significantly change the spatial configuration of the coordination template, and then directly affect the arrangement of the monomers, and only isophthalic acid and other auxiliary ligands with specific geometric configurations can construct ideal template structures to achieve efficient photo-dimerization and subsequent conversion.

[0081] Test Example 1

[0082] 1,5-bpvn crystals were obtained by dissolving 1,5-bpvn in dichloromethane to prepare a saturated solution, and then volatilizing after standing;

[0083] (1) The SCXRD analysis of 1,5-bpvn crystals was performed, and the solid-state molecular packing and crystallographic parameters are shown in Figure 18 and Table 1:

[0084] Table 1

[0085]

[0086] Note: aR1=Σ||Fo|–|Fc|| / Σ|Fo|.bwR2={Σw(Fo2–Fc2)2 / Σw(Fo2)2}1 / 2.cGOF={Σw((Fo2–Fc2)2)] / (n–p)}1 / 2, wherein n is the number of diffraction points, and p is the total number of refined parameters.

[0087] From Figure 18 and Table 1, it can be seen that in the crystal structure of 1,5-bpvn, the olefin double bonds of the crystal are not parallel to each other and have a distance greater than 4.2 Å, and therefore do not have the spatial geometric conditions required for the solid-phase [2+2] photocycloaddition reaction;

[0088] (2) The 1,5-bpvn crystal was irradiated under 100 W natural white light for 24 h to induce solid-state polymerization. After the reaction was completed, no obvious changes in macroscopic morphology and color were observed. At the same time, PXRD analysis was performed on the 1,5-bpvn crystal before (measured and simulated) and after light irradiation, and the results are shown in Figure 19 From Figure 19 it can be seen that the measured PXRD spectrum of the 1,5-bpvn crystal powder is highly consistent with the spectrum simulated based on the single crystal structure, confirming the high phase purity of the sample; by comparing the PXRD spectra before and after light irradiation, it is found that the diffraction peak positions remain consistent, and no new diffraction peaks appear, only the diffraction intensity changes, which indicates that the light irradiation process does not cause phase transition or structural reorganization of the sample; combined with the SCXRD analysis results, it can be known that the olefin double bonds in the 1,5-bpvn crystal structure are not parallel to each other and the distance between them is greater than 4.2 Å, which does not meet the spatial geometric conditions required for [2+2] photocycloaddition reaction, and direct light irradiation cannot induce solid-state polymerization of the sample; indicating that this type of 1,5-bpvn monomer cannot obtain a polymer single crystal through the traditional solid-state photopolymerization route without template pre-organization.

[0089] Test Example 2

[0090] Based on Example 1, [Cd(1,5-bpvn)(IPA)]n and [Cd(rctt-pncd)0.5(IPA)]n were characterized by nuclear magnetic resonance hydrogen spectrum, element, infrared spectrum, powder X-ray diffraction and single crystal X-ray diffraction, and the specific results are as follows:

[0091] (1) Nuclear magnetic resonance hydrogen spectrum analysis: the nuclear magnetic resonance hydrogen spectra of [Cd(1,5-bpvn)(IPA)]n and [Cd(rctt-pncd)0.5(IPA)]n are shown in Figures 20-21 From Figures 20-21 it can be seen that after [Cd(1,5-bpvn)(IPA)]n undergoes [2+2] photocycloaddition reaction to generate [Cd(rctt-pncd)0.5(IPA)]n containing a cyclobutane unit, the nuclear magnetic resonance hydrogen spectrum shows obvious characteristic chemical shift changes, in which the newly added absorption peak at the chemical shift of 5.83 ppm-5.53 ppm belongs to the signal peak of the proton on the cyclobutane, which directly confirms the generation of cyclobutane.

[0092] (2) Elemental analysis: The molecular formula of [Cd(l,5-bpvn)(IPA)]nis C32H22CdN2O4 (molecular weight 610.91), and the theoretical contents of C, H, and N are 62.91%, 3.63%, and 4.59%, respectively. The measured contents of C, H, and N are 62.88%, 3.65%, and 4.57%, respectively. The molecular formula and molecular weight of [Cd(rctt-pncd)0.5(IPA)]nare the same as those of the former (C32H22CdN2O4, M.W. = 610.91), and the theoretical contents of C, H, and N are also 62.91%, 3.63%, and 4.59%, respectively. The measured contents of C, H, and N are 62.72%, 3.68%, and 4.52%, respectively. The elemental analysis data show that the measured contents of C, H, and N of the two compounds are consistent with the theoretical values.

[0093] (3) Infrared spectroscopy analysis: The infrared spectra of [Cd(l,5-bpvn)(IPA)]nand [Cd(rctt-pncd)0.5(IPA)]nare shown in FIGS. 2 and 3, respectively. Figures 22-23

[0094] (4) Powder X-ray diffraction analysis: The PXRD spectra of [Cd(l,5-bpvn)(IPA)]nand [Cd(rctt-pncd)0.5(IPA)]nare shown in FIGS. 4 and 5, respectively. As can be seen from FIG. 4, the measured spectrum of [Cd(l,5-bpvn)(IPA)]nis highly consistent with the simulated spectrum based on its single crystal structure, confirming the high phase purity of the synthesized initial template. The measured spectrum of [Cd(rctt-pncd)0.5(IPA)]nis highly consistent with the simulated spectrum based on its own single crystal structure, and is significantly different from the PXRD spectrum of the initial template, which directly confirms that the photodimerization reaction has induced complete crystal phase transition of the sample. Figures 24-25 Figures 24-25

[0095] (5) Single crystal X-ray diffraction analysis: The crystallographic parameters of [Cd(l,5-bpvn)(IPA)]nand [Cd(rctt-pncd)0.5(IPA)]nare shown in Table 2:

[0096] Table 2

[0097]

[0098] Note: aR1=Σ||Fo|–|Fc|| / Σ|Fo|. bwR2={Σw(Fo2–Fc2)2 / Σw(Fo2)2}1 / 2. cGOF={Σw((Fo2–Fc2)2)] / (n–p)}1 / 2, where n is the number of diffraction points, and p is the total number of refined parameters.

[0099] ​​​As can be seen from Table 2, [Cd(l,5-bpvn)(IPA)]n and [Cd(rctt-pncd)0.5(IPA)]n were successfully prepared.

[0100] Test Example 3

[0101] Based on Example 1, rctt-pncd and poly-dpcn were characterized by nuclear magnetic hydrogen spectrum, high resolution mass spectrum, element, infrared spectrum, powder X-ray diffraction and single crystal X-ray diffraction, and the specific results are as follows:

[0102] (1) Nuclear magnetic spectrum analysis: the nuclear magnetic hydrogen spectra of rctt-pncd and poly-dpcn are shown in Figures 26-27 , and the solid nuclear magnetic resonance carbon spectra of rctt-pncd single crystal powder and poly-dpcn single crystal powder are shown in Figure 28 . As can be seen from Figure 26 , the characteristic peaks of the spectrum are clear and there is no obvious impurity interference peak, indicating that the dimer single crystal has been successfully extracted from the coordination polymer and has high purity; as can be seen from Figure 27 , the spectrum shows the characteristic chemical shift change corresponding to rctt-pncd, which confirms that the dimer single crystal has been successfully converted into an organic polymer; Figure 28 Further, it provides direct evidence for the occurrence of topological polymerization from the solid state. From the spectrum, it can be observed that the olefin carbon characteristic signal at 136.3 ppm after polymerization is obviously weakened, indicating that the olefin bond in the dimer single crystal has reacted selectively in the polymerization process, directly confirming the smooth progress of the topological polymerization.

[0103] (2) High resolution mass spectrum analysis: the high resolution electrospray ionization mass spectrum (HR-ESI-MS) analysis results of rctt-pncd are shown in Figure 29 , and the [M+H]+ molecular ion peak is detected at m / z 669.3024 in the positive ion mode, and the corresponding [C48H37N4]+ theoretical calculation value is 669.3016, which is highly consistent with the measured value, which not only further confirms the molecular structure of the dimer single crystal, but also provides strong evidence for the successful extraction and purification of rctt-pncd. The matrix assisted laser desorption ionization time of flight mass spectrum (MALDI-TOFMS) analysis results of the soluble component of poly-dpcn are shown in Figure 30 , and an obvious signal peak is observed at m / z 2027.503, which can be attributed to the hexamer [M6+Na+], and the measured molecular weight is highly consistent with the theoretical value, which directly confirms that the topological polymerization has successfully occurred and generated a regular polymer chain with a specific degree of polymerization, and this hexamer characteristic signal further proves the effectiveness of the topological polymerization.

[0104] (3) Elemental analysis: The elemental analysis data of rctt-pncd are as follows: the molecular formula is C48H36N4 (molecular weight 668.294), the theoretical value is C 86.20%, H 5.43%, N 8.38%, and the measured value is C 86.12%, H 5.38%, N 8.32%; the elemental analysis data of poly-dpcn are as follows: the molecular formula is (C24H18N2)n, the theoretical value is C 86.20%, H 5.43%, N 8.38%, and the measured value is C 86.05%, H 5.40%, N 8.31%, indicating that the measured values ​​of C, H, and N elements in rctt-pncd and poly-dpcn are consistent with the theoretical values.

[0105] (4) Infrared spectroscopy analysis: The infrared spectra of RCTT-PNCD and Poly-DPCN are shown below. Figures 31-32 As shown. From Figures 31-32 It can be seen that the absorption peak intensity of poly-dpcn at 963 cm⁻¹ is significantly weakened. This peak is attributed to the out-of-plane bending vibration of C=CH in the reactive olefin unit. The weakening of this characteristic signal corresponds to the consumption of reactive olefin bonds during the polymerization reaction, thus providing strong evidence for the successful topological polymerization.

[0106] (5) Powder X-ray diffraction analysis: The infrared spectra of RCTT-PNCD and Poly-DPCN are shown below. Figures 33-34 As shown. From Figures 33-34 It can be seen that the measured and simulated powder X-ray diffraction patterns of RCTT-PNCD are highly consistent, confirming that RCTT-PNCD crystal powder has high crystallinity and a single crystal phase. The measured and simulated powder X-ray diffraction patterns of Poly-DPCN are completely consistent, which not only confirms the high phase purity of Poly-DPCN, but also shows that it has been successfully transformed from RCTT-PNCD into a highly crystalline polymer single crystal. In particular, a new characteristic diffraction peak belonging to the (002) crystal plane was observed at 2θ=14.06°, and the full width at half maximum (FWHM) of the diffraction peak is ≤0.15°, further confirming the complete transformation from a dimer single crystal to a highly crystalline polymer single crystal.

[0107] (6) Single-crystal X-ray diffraction analysis: The crystallographic parameters of rctt-pncd and poly-dpcn are shown in Table 3:

[0108] Table 3

[0109]

[0110] Note: aR1 =∑||Fo|-|Fc|| / ∑|Fo|. bR2 = {∑w(Fo2-Fc2)2 / ∑w(Fo2)2}1 / 2. cGOF = {∑w((Fo2-Fc2)2)] / (n-p)}1 / 2, where n is the number of diffraction points and p is the total number of refined parameters.

[0111] As can be seen from Table 3, rctt-pncd and poly-dpcn have been successfully prepared. The crystallographic data further provides key evidence for the success of the topological polymerization: starting from the ordered dimer single crystal rctt-pncd, through photo-induced polymerization, the independent organic polymer single crystal poly-dpcn with clear long-range order has been successfully prepared.

[0112] In summary, the dimer-mediated organic polymer single crystal preparation method provided by the embodiments can efficiently break through the harsh restrictions of traditional solid-phase topological polymerization technology on monomer structure. Through the synergistic effect of coordination template directional assembly, photo-induced dimerization reconstruction, template dissociation purification, and in-situ topological polymerization of dimer single crystals, a series of alkenyl pyridine compounds that cannot satisfy the [2+2] photo-cycloaddition geometric conditions in solid state are accurately converted into structurally regular cyclobutane-based dimer precursors, and finally the intrinsic organic polymer single crystals with high crystallinity, long-range ordered structure, and self-supporting endogenous template are prepared. Experimental data show that the method has the outstanding characteristics of mild reaction conditions, simple and controllable steps, high product purity, and stable yield. It not only provides a new path for expanding the monomer application range of organic polymer single crystals, improving the crystalline integrity and functional stability of materials, but also lays an important material foundation for the development of the next generation of organic electronic devices. The prepared high-performance organic polymer single crystals have significant scientific value and broad industrial application prospects.

[0113] Obviously, the above embodiments are merely examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, all embodiments need not and cannot be exhaustively enumerated. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing a dimer-mediated organic polymer single crystal, characterized by, Includes the following steps: S1, metal salt, alkenylpyridine ligands and auxiliary ligands are coordinated self-assembled in a solvent, and the coordination polymer single crystal reaction template is obtained after washing and drying; The structural formula of the alkenylpyridine ligand is as follows: R is selected from substituted or unsubstituted phenyl, naphthyl, or anthracene; the substituted group is fluorine, chlorine, hydroxyl, methyl, or methoxy; the metal salt is selected from cadmium salt and / or manganese salt; the auxiliary ligand is selected from one or more of isophthalic acid, p-chlorobenzoic acid, p-bromobenzoic acid, 5-chloroisophthalic acid, 5-bromoisophthalic acid, and 4,4′-diphenyl ether dicarboxylic acid; S2. Under ultraviolet or visible light irradiation, the coordination polymer single crystal reaction template described in S1 undergoes a [2+2] photocycloaddition reaction to obtain a coordination polymer containing cyclobutane dimers. S3. Under the action of alkaline or acidic solution, the coordination polymer containing cyclobutane dimer described in S2 is dissociated, and the dimer single crystal is obtained by extraction, concentration and recrystallization. S4. Under ultraviolet or visible light irradiation, the dimer single crystal described in S3 undergoes a topological chemical polymerization reaction to obtain the organic polymer single crystal.

2. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, The cadmium salt is selected from one or more of cadmium nitrate, cadmium chloride, and cadmium sulfate; And / or, the manganese salt is manganese nitrate.

3. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S1, the molar ratio of the metal salt, alkenylpyridine ligand, and auxiliary ligand is 1:(0.8-1.2):(0.8-1.2).

4. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S1, the temperature for coordination self-assembly is 110℃-180℃, and the time is 8h-48h.

5. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S2, the irradiation power is 10W-30W and the time is 0.5h-5.0h.

6. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S3, the alkaline solution is a sodium hydroxide solution; And / or, the acid solution is selected from nitric acid solution or hydrochloric acid solution; And / or, the concentrations of the alkaline solution and the acid solution are independently 0.5 mol / L to 1.5 mol / L.

7. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S3, the solvent used for extraction is selected from dichloromethane or trichloromethane.

8. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S3, the solvent system for recrystallization is a mixture of dichloromethane and petroleum ether.

9. The method for preparing dimer-mediated organic polymer single crystals according to claim 1, characterized in that, In S4, the irradiation power is 90W-110W, and the time is 18h-36h.

Images