A macrocyclic-small molecule eutectic material with adjustable structure and luminescence, and its preparation method and application

Abstract

The present invention discloses a macrocyclic-small molecule eutectic material with adjustable structure and luminescence, its preparation method and application, which is assembled by donor molecules and acceptor molecules through intermolecular charge transfer, wherein the donor is a triangular pyrene-based macrocyclic molecule and the acceptor is 1,2,4,5-tetracyanobenzene. The present invention is characterized in that, by regulating the crystallization solvent, the prepared macrocyclic-small molecule eutectic has the characteristics of diverse stoichiometric ratios and assembly structures, and the material exhibits excellent luminescence tunable properties. The material provided by the present invention has the advantages of simple preparation method, low cost, scalability, etc., and has potential application prospects in multicolor display devices and light-emitting devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of eutectic materials, and specifically relates to a macrocyclic-small molecule eutectic material with adjustable structure and luminescence, and a preparation method and application thereof. Background Art

[0002] Organic co-crystal engineering involves the co-assembly of two or more different organic molecules through non-covalent interactions such as π-π stacking, halogen bonding, and hydrogen bonding to form molecular crystals with fixed stoichiometric ratios and ordered stacking structures. Unlike traditional single-component crystalline materials, which involve the breaking and forming of covalent bonds, organic co-crystals offer several unique advantages: simple and low-cost preparation techniques, without the need for complex chemical synthesis steps and demanding experimental conditions; the co-crystal structure, size, morphology, and stoichiometric ratio can be easily manipulated by selecting appropriate co-crystal pairs or changing solvents; and the unique molecular stacking and aggregation structures between two or more components, as well as their integration and synergistic effects, allow organic co-crystals to not only retain the inherent properties of the individual components but also exhibit more novel characteristics. These organic co-crystals have significant research value and application prospects in optoelectronic materials, stimuli-responsive materials, and the pharmaceutical industry.

[0003] Traditional organic co-crystals are almost all assembled from small planar donor-acceptor molecules, and their crystal structures are usually in two modes: separate stacking and mixed stacking. This has, to a certain extent, resulted in deficiencies in the structural diversity and functional expansion of organic co-crystals. Macrocyclic molecules have inherent cavities and polygonal skeleton structures. Combining macrocyclic molecules with organic planar small molecules can theoretically construct macrocyclic-small molecule co-crystal materials with diverse assembly structures and exhibit some rare functions. However, there are still few reports based on macrocyclic-small molecule co-crystals, mainly due to the lack of macrocyclic compounds with effective assembly driving force skeletons. Therefore, it is very meaningful and challenging to design and synthesize polygonal macrocycles with skeleton assembly driving forces and small molecules to construct structurally diverse macrocyclic-small molecule co-crystal materials through non-covalent matching and achieve functional regulation. Summary of the Invention

[0004] Based on this, the present invention proposes a macrocyclic-small molecule organic cocrystal material with tunable structure and luminescence, its preparation method, and its application in multicolor display devices and light-emitting devices. Using a pyrenyl macrocycle (hereinafter referred to as Py) and 1,2,4,5-tetracyanobenzene (hereinafter referred to as TCNB) as raw materials, the present invention prepares two-component cocrystal materials with diverse stoichiometric ratios and assembly structures under appropriate conditions. In specific embodiments, Py-1, Py-2, and Py-3 are prepared. Under irradiation with ultraviolet light at a wavelength of 365 nm, the cocrystal emits yellow light at wavelengths of 570 nm, orange light at 603 nm, and red light at 639 nm, respectively. The present invention also provides a method for preparing the macrocyclic-small molecule cocrystal material, which offers advantages such as simplicity, no need for complex chemical synthesis, mild growth conditions, low cost, and scalability.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A structurally and luminescently tunable macrocyclic-small molecule organic cocrystal material is characterized by utilizing an electron-rich Py donor and an electron-poor TCNB acceptor as the cocrystal building blocks. By adjusting the crystallization solvents of the macrocyclic and small molecule, three macrocyclic-small molecule cocrystals with different donor-acceptor stoichiometric ratios (2:1, 1:1, and 2:3) and assembly structures were obtained, exhibiting multicolor luminescence tuning. The driving force for the assembly between the molecules is charge transfer interaction. The structures of Py and TCNB are shown in Formulas I and II:

[0007]

[0008] Wherein, R is methyl, ethyl or n-propyl.

[0009] The preparation steps are:

[0010] (1) Weigh the compounds of formula I and formula II in a ratio of 1:3, add them into a solvent of tetrahydrofuran, dioxane and dichloromethane, and filter after fully dissolving them;

[0011] (2) Transfer the filtered solution into a glass bottle and cover it with a cap. It does not need to be completely sealed. Allow the solvent to evaporate slowly at room temperature or low temperature for 3 to 7 days. After a period of time, three macrocyclic-small molecule cocrystal materials with different donor-acceptor ratios and assembly structures can be obtained.

[0012] The macrocyclic-small molecule eutectic material Py-1 belongs to the triclinic system and has a space group of P-1, and its unit cell parameters are: a =16.073(3), b = 17.902(3), c = 23.748(4), α = 108.627(5)°, β = 92.658(6)°, γ =102.860(6)°.

[0013] The macrocyclic-small molecule eutectic material Py-2 belongs to the triclinic system, and the space group is P -1, and its unit cell parameters are: a =19.465(2), b = 19.978(2), c = 20.219(2), α = 93.593(3)°, β = 116.099(3)°, γ =99.007(3)°.

[0014] The macrocyclic-small molecule eutectic material Py-3 belongs to the triclinic system, and the space group is P -1, and its unit cell parameters are: a =17.933(3), b = 19.019(3), c = 23.176(4), α = 72.498(5)°, β = 70.940(4)°, γ =75.284(5)°.

[0015] In the Py-1 structure, the pyrene-based skeleton on one side of the macrocyclic molecule undergoes charge transfer with one TCNB to form a 2:1 charge transfer complex; in the Py-2 structure, the pyrene-based skeletons on two sides of the macrocyclic molecule simultaneously undergo charge transfer with two TCNBs to form a 1:1 charge transfer complex; in the Py-3 structure, the pyrene-based skeletons on three sides of the macrocyclic molecule simultaneously undergo charge transfer with three TCNBs to form a 2:3 charge transfer complex.

[0016] In the three macrocyclic-small molecule eutectic structures, as the degree to which the polygonal skeleton of the macrocyclic molecule participates in charge transfer increases, the three eutectic materials exhibit yellow, orange and red red-shifted luminescence properties, respectively.

[0017] The present invention further discloses the application of a macrocyclic-small molecule organic eutectic material with adjustable structure and luminescence in multi-color display devices and light-emitting devices.

[0018] Compared with the prior art, the present invention has at least the following advantages:

[0019] (1) The present invention provides a novel macrocyclic-small molecule cocrystal luminescence modulating material. Compared with small molecule cocrystals, the material has the advantage of a more diverse assembly structure. In the cocrystal material structure, the triangular macrocyclic ring can adjust the assembly stacking structure by the amount of charge transfer involved in its own skeleton, thereby adjusting the luminescence color of the material. This is difficult to achieve with a fixed-component small molecule cocrystal assembly structure.

[0020] (2) The present invention provides a method for preparing the macrocyclic-small molecule material, which cleverly combines macrocyclic chemistry and eutectic engineering to expand into a new field of macrocyclic eutectic materials. Through this preparation method, eutectic materials with rare functions that are difficult to achieve with traditional small molecule eutectics can be obtained.

[0021] (3) The preparation method of the macrocyclic-small molecule co-crystal luminescent tunable material has the advantages of simplicity, strong assembly driving force, low cost, and scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The color changes of the three macrocyclic-small molecule co-crystals prepared in Example 1: a is Py-1 crystal, b is Py-2 crystal, and c is Py-2 crystal;

[0023] Figure 2 The single crystal structure diagram of Py-1 in Example 2;

[0024] Figure 3 The single crystal structure diagram of Py-2 in Example 3;

[0025] Figure 4 The single crystal structure of Py-3 in Example 4;

[0026] Figure 5 is the fluorescence spectrum of the Py-1 cocrystal in Example 5;

[0027] Figure 6 is the fluorescence spectrum of the Py-2 cocrystal in Example 5;

[0028] Figure 7 This is the fluorescence spectrum of the Py-3 cocrystal in Example 5. DETAILED DESCRIPTION

[0029] The present invention is described below through specific embodiments. Unless otherwise specified, the technical means used in the present invention are methods well known to those skilled in the art. In addition, the embodiments should be understood as illustrative rather than limiting the scope of the invention, and the essence and scope of the invention are limited only by the claims. For those skilled in the art, various changes or modifications to the material components and amounts in these embodiments, without departing from the essence and scope of the invention, also fall within the scope of protection of the present invention. The synthesis method of the pyrenyl macrocycle (Formula I) used in the present invention is described in Chunju Li et al. in Angew. Chem. Int. Ed., Vol. 59, 2020, pp. 7214–7218. 1,2,4,5-tetracyanobenzene (Formula II) is a commercially available raw material.

[0030] Example 1

[0031] Preparation of macrocyclic-small molecule cocrystal materials:

[0032] (1) Preparation of Py-1 cocrystal: Weigh 1.46 g Py and 0.53 g TCNB, add them to 10 mL tetrahydrofuran solution, and filter with a 0.22 μm organic filter membrane after fully dissolving. Transfer the filtered solution to a 20 mL glass bottle, cover the bottle cap (it does not need to be completely sealed), and slowly evaporate the solvent at room temperature for 3 days to obtain a two-component rod-shaped crystal ( Figure 1 a), denoted as Py-1.

[0033] (2) Preparation of Py-2 cocrystal: Weigh 1.46 g Py and 0.53 g TCNB, add them to 10 mL dioxane solution, fully dissolve under heating conditions, and filter with a 0.22 μm organic filter membrane. The filtered solution is transferred to a 20 mL glass bottle, covered with a cap, and the solvent is slowly evaporated at room temperature for 5 days to obtain a two-component bulk crystal ( Figure 1 b), denoted as Py-2.

[0034] (3) Preparation of Py-3 cocrystal: Weigh 1.46 g Py and 0.53 g TCNB, add them to 10 mL dichloromethane solution, fully dissolve under heating, and filter with a 0.22 μm organic filter membrane. The filtered solution is transferred to a 20 mL glass bottle, covered with a cap, and the solvent is slowly evaporated at room temperature for 2 days to obtain a two-component tetragonal crystal ( Figure 1 c), denoted as Py-3.

[0035] Example 2

[0036] Py-1 single crystal X-ray diffraction analysis. Its unit cell parameters are: a = 16.073(3), b = 17.902(3), c = 23.748(4), α = 108.627(5)°, β = 92.658(6)°, γ = 102.860(6)°. The specific single crystal structure shows that, Figure 2 As shown, in the Py-1 structure, one TCNB molecule binds to two macrocycle molecules, forming a sandwich charge-transfer complex through face-to-face π···π interactions. The nitrogen atoms of TCNB further stabilize the complex through CH…N interactions with hydrogen atoms on the macrocycle. Simultaneously, the other side of the macrocycle in the stacking structure forms a parallelogram dimer with the adjacent macrocycle through parallel π…π stacking interactions.

[0037] Example 3

[0038] Py-2 single crystal X-ray diffraction analysis. Its unit cell parameters are: a = 19.465(2), b = 19.978(2), c = 20.219(2), α = 93.593(3)°, β = 116.099(3)°, γ = 99.007(3)°. The specific single crystal structure shows that, Figure 3 As shown in the Py-2 structure, the two edges of the macrocycle undergo charge transfer interactions with TCNB. In the stacking structure, each macrocycle molecule assembles into a tetrameric basic unit through CH…O, CH…π, and π…π interactions with adjacent macrocycle molecules.

[0039] Example 4

[0040] Py-3 single crystal X-ray diffraction analysis. Its unit cell parameters are: a = 17.933(3), b = 19.019(3), c = 23.176(4), α = 72.498(5)°, β = 70.940(4)°, γ = 75.284(5)°. The specific single crystal structure shows that, Figure 4 As shown in the crystal structure of Py-3, the three edges of the macrocycle simultaneously undergo charge transfer interactions with TCNB to form a complex. Multiple CH…N and CH…O interactions between the macrocycle and TCNB further stabilize the charge transfer complex.

[0041] Example 5

[0042] The obtained co-crystals were taken out with a pipette along with a small amount of culture medium and placed in a clean culture dish. The luminescence of the three co-crystals was observed under a fluorescence microscope at 365 nm. The results showed that Py-1 emitted yellow light, Py-2 emitted orange light, and Py-3 emitted red light. Figure 5 As shown in Figure 7, fluorescence spectra further reveal that the emission wavelengths of the three cocrystals are 570, 603, and 639 nm, respectively. Compared to the macrocycle alone (emission wavelength of 300 nm), the three cocrystals exhibit significantly red-shifted emission. These results suggest that macrocycle-small molecule cocrystals provide a new strategy for the preparation of solid-state luminescence-modulating materials, with potential applications in multicolor display devices and light-emitting devices.

[0043] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A macrocyclic-small molecule organic eutectic material with adjustable structure and luminescence, characterized in that: Using an electron-rich Py donor and an electron-deficient TCNB small molecule acceptor as cocrystal building blocks, and by regulating the crystallization solvents of the macrocycle and small molecule, three macrocyclic cocrystals, Py-1, Py-2, and Py-3, were obtained, with donor-acceptor stoichiometric ratios of 2:1, 1:1, and 2:3, respectively. in The macrocyclic and small molecule structures are shown as Ⅰ and Ⅱ respectively: ; The Py donor refers to: a pyrenyl macrocycle, R is a methyl group; The unit cell parameters of the three eutectics are: Py-1: a = 16.073(3), b = 17.902(3), c = 23.748(4), α = 108.627(5)°, β =92.658(6)°, γ = 102.860(6)°; Py-2: a = 19.465(2), b = 19.978(2), c = 20.219(2), α = 93.593(3)°, β = 116.099(3)°, γ = 99.007(3)°; Py-3: a = 17.933(3), b = 19.019(3), c = 23.176(4), α = 72.498(5)°, β = 70.940(4)°, γ = 75.284(5)°.

2. The method for preparing the macrocyclic-small molecule organic co-crystal material with adjustable structure and luminescence according to claim 1, characterized in that: The macrocyclic molecule and the small molecule are mixed in proportion and dissolved in three organic solvents respectively. Three macrocyclic-small molecule eutectic materials with diverse stoichiometric ratios and assembly structures are obtained by slow volatilization of the solution at room temperature; among them, the crystallization solvent of Py-1 is tetrahydrofuran; the crystallization solvent of Py-2 is dioxane; and the crystallization solvent of Py-3 is dichloromethane; the mixing molar ratio of the macrocyclic I and the small molecule II is 1:

3.

3. The macrocyclic-small molecule organic eutectic material with adjustable structure and luminescence according to claim 1, characterized in that: The eutectic Py-1, Py-2 and Py-3 emit yellow, orange and red light, respectively.

4. Application of the macrocyclic-small molecule organic eutectic material with the structure and luminescence tunable according to claim 1 in multi-color display devices and light-emitting devices.

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