阅读说明：本技术 一种氰基取代的螺环芳烃分子分形晶体及其制备方法和应用 (Cyano-substituted spiro-aromatic hydrocarbon molecule fractal crystal and preparation method and application thereof ) 是由 金凌志 张翀 解令海 汪莎莎 黄维 于 2021-07-13 设计创作，主要内容包括：本发明公开了一种氰基取代的螺环芳烃分子分形晶体及其制备方法和应用,所述分形晶体是由氰基取代的螺环芳烃分子十字堆积有序排列形成；SAHs被超分子作用基团取代,本身起到位阻的作用,对称取代的超分子作用基团引入对称且较强的超分子作用力,通过浓度和温度调控实现了SAHs晶体的分枝生长和尖端破裂,进而形成分形晶体,可作为光电材料广泛应用于光电器件中,且具有荧光发光稳定性。(The invention discloses a cyano-substituted spiro arene molecule fractal crystal and a preparation method and application thereof, wherein the fractal crystal is formed by cross-shaped stacking ordered arrangement of cyano-substituted spiro arene molecules; SAHs are replaced by supramolecular acting groups, the supramolecular acting groups play a role in steric hindrance, symmetric and strong supramolecular acting forces are introduced into the symmetrically substituted supramolecular acting groups, the branched growth and tip fracture of SAHs crystals are realized through concentration and temperature regulation, fractal crystals are further formed, and the fractal crystals can be widely applied to photoelectric devices as photoelectric materials and have fluorescence luminescence stability.)

1. The cyano-substituted spiro-arene molecule fractal crystal is characterized in that the fractal crystal is formed by crossed stacking and ordered arrangement of cyano-substituted spiro-arene molecules, the molecular configuration of the cyano-substituted spiro-arene molecules is that two crossed planes share a central carbon atom, cyano groups are respectively substituted at 2, 7, 3 'and 6' positions, and the structural formula is as follows:

2. a cyano-substituted spirocyclic arene molecule fractal crystal according to claim 1, having an X-ray powder diffraction pattern with diffraction peaks at the following diffraction angles, 2 Θ: 5.47,6.49, 32.82, 47.59, 54.43, 56.20.

3. The cyano-substituted spirocyclic arene molecule fractal crystal according to claim 1, wherein an X-ray powder diffraction pattern of the fractal crystal has the following diffraction peaks:

2θ 5.47 6.49 32.82 47.59 54.43 56.20 I％ 11.0 100.0 69.1 63.2 12.2 19.5

。

4. a preparation method of cyano-substituted spiro arene molecule fractal crystals is characterized by comprising the following steps: dissolving cyano-substituted spiro arene molecules with a certain mass in an organic solvent to prepare cyano-substituted spiro arene molecule solution with the concentration of 4-16mM, injecting the cyano-substituted spiro arene molecule solution into a violently stirred anionic surfactant aqueous solution, uniformly stirring, and standing at the temperature of 40-80 ℃ to obtain the fractal crystal.

5. The method for preparing cyano-substituted spiroarene molecule fractal crystals according to claim 4, wherein the concentration of the anionic surfactant aqueous solution is 2-4 mg/mL.

6. The method for preparing cyano-substituted spirocyclic arene molecule fractal crystals according to claim 4, wherein the volume ratio of the cyano-substituted spirocyclic arene molecule solution to the anionic surfactant aqueous solution is 1: 5.

7. the method for preparing cyano-substituted spiroarene molecule fractal crystals according to claim 4, wherein the standing time in an environment of 40-80 ℃ is 24-72 h.

8. The method for preparing the cyano-substituted spirocyclic arene molecule fractal crystal according to claim 4, wherein the organic solvent is any one of tetrahydrofuran, dichloromethane and chlorobenzene.

9. The method for preparing cyano-substituted spirocyclic arene molecule fractal crystals according to claim 4, wherein the anionic surfactant is SDS or sodium dodecyl benzene sulfonate.

10. The application of the cyano-substituted spiroarene molecule fractal crystal in photoelectric materials, which is described in any one of claims 1 to 3, is characterized in that the cyano-substituted spiroarene molecule fractal crystal is used as a luminescent material in an organic electroluminescent device.

Technical Field

The invention belongs to the technical field of organic micro-nanocrystalline materials, and particularly relates to a cyano-substituted spiro-aromatic hydrocarbon molecule fractal crystal, and a preparation method and application thereof.

Background

For billions of years, nature has presented numerous simple and complex chemical structures with fractal morphologies, including snowflakes, leaves, branches, coastlines, and the like. Among them, the snowflake crystal has been widely reported as the most common crystal structure having a regular hexagonal fractal shape. The fractal structure is an important milestone urgently needed in the history of material engineering, not only fills up the missing link among integer-dimensional structures, but also provides an excellent model for structural research. The fractal crystal material is composed of long-period ordered units with unique morphology, has great advantages in crystal engineering, opens up new research fields in the aspects of structure, analysis, technology, theory and the like, and becomes an attractive research target for basic research and further application.

Fractal structures have geometric aesthetics and model research significance, and are widely applied to the fields of surface chemistry, device manufacturing, electronics, optoelectronics, biomaterials and the like at present. In the field of devices, due to the fact that the fractal structure has a large specific surface area and a complex surface structure, the hydrophilicity and hydrophobicity of an interface can be regulated and controlled through interface modification of the fractal structure and a functional group, and the photoelectric performance and stability of a material can be improved.

Organic molecules have condensed molecular configurations and conformations, which have important effects on the interactions between supramolecules, the way the molecules are stacked and the final crystal morphology. The role of different functional groups in organic systems and the complex interactions of multiple intermolecular interactions are not clear, making accurate morphological predictions difficult. So far, regular organic molecule fractal crystals have not been reported, and the corresponding crystallography theory is blank.

The publication number CN109651328A discloses a pyrenyl spiro aromatic organic nanocrystal material and a patent publication document of a preparation method and application thereof, and discloses a pyrenyl spiro aromatic organic nanocrystal material, which is prepared by adding a surfactant to a pyrenyl spiro aromatic compound, wherein the pyrenyl spiro aromatic compound is a molecule consisting of spiro aromatic hydrocarbon and pyrene, and the spiro aromatic hydrocarbon is one of spirofluorene, spirofluorene xanthene or benzospirofluorene xanthene; the prepared nano structure has regular shape and uniform size, and the controllable preparation of the one-dimensional to two-dimensional organic nano structure is realized. The patent documents also describe that the pyrenyl spiro aromatic hydrocarbon organic nanocrystal material can be applied to organic semiconductors, but the controllable preparation is limited to one-dimensional to two-dimensional organic nanostructures and is not a regular fractal structure.

Disclosure of Invention

The invention prepares a cyano-substituted Spiro Aromatic Hydrocarbon (SAHs) fractal crystal material through water-like molecular design, realizes that the steric supramolecular steric hindrance effect (SSH effect) of the water-like spiro aromatic hydrocarbon is not limited to two-dimensional assembly, and can form a more complex molecular stacking mode and morphology of micro/nano crystals.

In order to achieve the purpose, the invention adopts the technical scheme that:

in a first aspect, the invention provides a cyano-substituted spiro arene molecule fractal crystal, which is a cross-stacked fractal crystal formed by ordered arrangement of cyano-substituted spiro arene molecules with a water-like structure, wherein the cyano-substituted spiro arene molecule (TCN-SFX) has the following structural formula:

the cyano-substituted spiro arene molecule is a spiro arene monomer molecule with a water-like structure, the cyano-substituted spiro arene molecule is adopted, the molecular conformation and the molecular arrangement mode of the TCN-SFX molecule in the crystal are such that two crossed planes share a central carbon atom, and the cyano groups are substituted at 2, 7, 3 'and 6' positions respectively;

the X-ray powder diffraction pattern of the fractal crystal has diffraction peaks at the following diffraction angles 2 theta: 5.47,6.49, 32.82, 47.59, 54.43, 56.20.

Based on the water-like molecular design, as shown in the schematic diagram of the molecular stacking process in the water molecular structure and the crystal in figure 1, SAHs are replaced by supramolecular acting groups, and the supramolecular acting groups which are symmetrically replaced introduce symmetrical and strong supramolecular acting force to form cross stacking and morphology through further induction; FIG. 2 is a schematic diagram showing the molecular stacking process of TCN-SFX water-like molecular design and prediction according to the present invention.

In a second aspect, the invention provides a preparation method of a cyano-substituted spiro-aromatic hydrocarbon molecule fractal crystal, which is based on a re-precipitation preparation method, realizes the branch growth and tip fracture of SAHs crystals through concentration and temperature regulation and control, and further forms the fractal crystal;

dissolving TCN-SFX with a certain mass in an organic solvent to prepare a TCN-SFX solution with the concentration of 4-16mM, injecting the TCN-SFX solution into a vigorously stirred anionic surfactant aqueous solution with the concentration of 2-4mg/mL, wherein the volume ratio of the TCN-SFX solution to the anionic surfactant aqueous solution is 1:5, stirring for 5-10 minutes, and standing for 24-72 hours at the temperature of 40-80 ℃ to obtain the fractal crystal.

Preferably, the organic solvent is tetrahydrofuran, dichloromethane or chlorobenzene.

Preferably, the anionic surfactant is SDS or sodium dodecyl benzene sulfonate.

Analyzing the structure-activity relationship, wherein the main stacking arrangement directions of the molecules are [100] and [010], and the directions are strong forces of a group of four hydrogen bonds provided by cyano groups, so that the cross stacking mode of the molecules is caused; under high temperature conditions, the strong hydrogen bonds can still maintain their assembly advantages and widen the gap compared to other supramolecular forces, leading to branch growth and tip breakage of SAHs crystals, thereby forming fractal crystals.

In a third aspect, the cyano-substituted spiro arene molecule fractal crystal provided by the invention is applied to photoelectric materials, the cyano-substituted spiro arene molecule fractal crystal shows blue luminescence under laser excitation, and compared with TCN-SFX amorphous films and crystals with other morphologies, the fractal crystal has better fluorescence luminescence stability.

Compared with the prior art, the invention has the following beneficial effects:

in a first aspect, theThe invention provides a fractal crystal structure of water-like spiro-arene, the shape of the fractal crystal is a centrosymmetric cross fractal structure, the length is 50 +/-10 um, the thickness is 10 +/-2 um, and the fractal dimension of the structure is D_f1.8353 ± 0.1401. The crystal still keeps excellent shape stability and luminescence stability under the laser irradiation condition;

in a second aspect, the invention provides a preparation method of the crystal structure, based on a reprecipitation method, the preparation of the crystal structure can be realized according to a structure-activity relationship and by regulating and controlling temperature and concentration, and the prepared fractal crystal structure is good in crystallinity, uniform in size, and good in morphology stability and luminescence stability;

in a third aspect, the water-like spiro aromatic hydrocarbon fractal crystal structure provided by the invention utilizes the SSH effect of SAHs, so that the crystal structure of spiro aromatic hydrocarbon is not limited to two-dimensional assembly any more, and can be used for designing and predicting the molecular stacking mode and morphology of more complex micro/nano crystals.

Drawings

FIG. 1 is a schematic diagram of the structure of water molecules and the molecular packing in crystals;

FIG. 2 is a TCN-SFX water-based molecular design and prediction of molecular packing;

FIG. 3 is a morphology characterization of the fractal crystals prepared in examples 1-4;

FIG. 4 is a morphology and structure characterization of the fractal crystal prepared in example 5;

FIG. 5 is the morphology of the fractal crystal growth evolution process during the preparation of example 5;

FIG. 6 is a single crystal structural view of TCN-SFX described in test example 2;

FIG. 7 is a stacking pattern and repeating units of the TCN-SFX fractal crystals described in test example 2;

FIG. 8 is the morphology of the TCN-SFX fractal crystal before and after laser beam irradiation in test example 3;

FIG. 9 shows the micro-area laser excited luminescence and spectral characterization of the TCN-SFX fractal crystal in test example 3;

FIG. 10a is a graph showing the luminous intensity of the TCN-SFX amorphous film in test example 3 under different power laser irradiation;

FIG. 10b is a graph showing the luminescence intensity of crystals of other TCN-SFX morphologies in test example 3 under different power laser irradiation;

FIG. 10c is a graph showing the luminous intensity of the TCN-SFX fractal crystal in test example 3 under different power laser irradiation;

FIG. 11 is a crystal morphology characterization of the other morphology crystals of TCN-SFX corresponding to FIG. 10c in test example 3;

FIG. 12 is an X-ray powder diffraction pattern of the TCN-SFX fractal crystal prepared in example 5.

Detailed Description

The invention is further described with reference to the following figures and examples.

The invention provides a preparation method of a water-like spiro-aromatic fractal crystal structure, which obtains a regular cross-shaped fractal crystal by a reprecipitation method and realizes a fractional-dimensionality spiro-aromatic molecular micro/nano structure. The crystal has good crystallinity, uniform size, good appearance and good luminescence stability. In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings. However, the technical contents of the present invention are not limited to the following examples.

Example 1-example 5: preparation method of TCN-SFX fractal crystal

Weighing a TCN-SFX sample with a certain mass into a 10mL sample bottle, adding 1mL tetrahydrofuran for fully dissolving, preparing into a TCN-SFX tetrahydrofuran solution with the concentration range of 4-8mM, quickly injecting the TCN-SFX tetrahydrofuran solution into the vigorously stirred sample bottle of 5mL SDS aqueous solution, covering a cover, stirring for 5 minutes, taking out magnetons, standing for 72 hours at the temperature of 40-80 ℃ to obtain a suspension of fractal crystals, and volatilizing the solvent to obtain the fractal crystals.

Examples 1-5, the only differences between the different examples are the sample concentration and the temperature of the preparation environment, the remaining parameters and steps are the same, and the sample concentration and the setting conditions of the preparation environment for each specific example are detailed in the following table:

test example 1: TCN-SFX fractal crystal morphology characterization

The suspension of fractal crystals prepared in example 1 to example 5 was centrifuged, washed four times with pure water and sampled; 20 μ L of the suspension was measured with a pipette and dropped onto a clean, dry silicon wafer substrate. The solvent was completely evaporated and then observed and tested with a field emission scanning electron microscope at an accelerating voltage of 5kV and an emission current of 10. mu.A.

As shown in fig. 3, which is an electron micrograph showing the test results of the TCN-SFX fractal crystals prepared in examples 1 to 4, it can be seen that the TCN-SFX molecules can self-assemble to form a regular fractal structure under the preparation conditions of examples 1 to 4.

As shown in fig. 4a, the test result of the TCN-SFX fractal crystal prepared in example 5 is shown, and the crystal morphology of the crystal is a cross fractal structure with central symmetry according to the crystal morphology photograph under an electron microscope.

Through observation and test under a transmission electron microscope and calibration of diffraction spots in selected areas, as shown in FIG. 4b, the fractal crystal has better crystallinity and the growth directions of branches thereof are respectively [100] and [010 ];

as shown in fig. 5, the growth history of the fractal crystal prepared for example 5 includes branch growth and a tip splitting process.

As can be seen from the dimensional measurements of the TCN-SFX fractal crystals prepared in examples 1 to 5, the TCN-SFX fractal crystals prepared in examples 1 to 5 had a length of 50. + -. 10. mu.m and a thickness of 10. + -. 2. mu.m, and the fractal dimension of the structure of the fractal crystal in each example, D, was calculated by Matlab software_f＝1.8353±0.1401。

The crystalline forms of the TCN-SFX fractal crystals prepared in examples 1 to 5 were characterized by X-ray powder diffraction pattern having diffraction peaks at the following diffraction angles 2 θ: 5.47,6.49, 32.82, 47.59, 54.43, 56.20.

As shown in fig. 12, an X-ray powder diffraction pattern of the fractal crystal prepared in example 5 has the following diffraction peaks:

2θ	5.47	6.49	32.82	47.59	54.43	56.20
							I％	11.0	100.0	69.1	63.2	12.2	19.5

test example 2: TCN-SFX molecular stacking and structure effect test and analysis

In the TCN-SFX fractal crystals prepared in examples 1 to 5, the molecular conformation and the molecular arrangement of TCN-SFX molecules in the crystal, i.e., the single crystal structure of TCN-SFX, were investigated by MERCURY software, and as shown in fig. 6, the TCN-SFX molecules share a central carbon atom for two planes crossed in a cross, and the dihedral angle of the fluorene plane and the xanthene plane was 89.36 °.

FIG. 7A shows the minimal repeating unit of a TCN-SFX molecule during stacking, consisting of a set of eight molecules in different spatial positions, at [100]]And [010]Strong forces directed towards a set of four hydrogen bonds provided by the cyano group: FIG. 7B, C shows a graph at [010]]And [100]]The upper molecular stacking units are stacked by the plane pi among molecules; FIG. 7D, E shows a graph at [010]]And [100]]Upper molecular packing pattern. The arrangement of CN-SFX molecules on the axes a, b and c is that the main stacking arrangement direction of the molecules is [100]]And [010]The strong forces of a group of four hydrogen bonds provided by cyano groups in the direction of the fractal crystal lead to a mode of molecular cross stacking, which is an extended dominant direction of molecular stacking in the fractal crystal. Through calculation of the activation energy in each crystal orientation, under the high-temperature condition, compared with other supermolecule acting forces, the strong hydrogen bonds can still keep the assembly advantages and draw the difference along with the temperature rise, so that the branch growth and the tip splitting of the SAHs crystal are caused, and D is further formed_f1.8353 + -0.1401.

The experimental results and the software analysis results show the dominant growth direction of the molecules, and clearly illustrate the molecular arrangement mode. Based on the strong hydrogen bond induced cross assembly, the fractal structure is assembled under the regulation and control of a temperature field.

Test example 3: TCN-SFX fractal crystal morphology and luminescence stability test and analysis

Centrifuging and cleaning the suspension of the fractal crystal prepared in the embodiment 5, placing the suspension on a silicon wafer substrate, irradiating the suspension for 10s by using a laser beam with the power of 0.5mW, and carrying out in-situ observation on the fractal crystal before and after irradiation by using an optical microscope, wherein the result is shown in fig. 8, and the fractal crystal keeps excellent morphology stability;

fig. 9a shows the fractal crystal prepared in example 5 observed in the bright field mode of the optical microscope, under the excitation of laser, as shown in fig. 9b, the crystal in fig. 9a shows the luminescence condition under the laser for the in-situ observation in the dark field mode of the optical microscope, the fractal crystal can be observed to show blue luminescence through the optical microscope, and as shown in fig. 9c, the fractal crystal prepared in example 5 shows the in-situ fluorescence spectrum, and the emission peak position can be seen to be about 420 nm.

Observing the real-time change condition of the in-situ fluorescence emission intensity before and after 500s of the TCN-SFX fractal crystal prepared in the example 5 under the laser radiation with different powers (0.1-0.7 mW), as shown in FIG. 10 c;

in order to embody the stability advantage of the crystal structure of the TCN-SFX fractal crystal in the aspect of photoelectric performance, the TCN-SFX amorphous film and other morphological crystals of the TCN-SFX are used as a reference, and the real-time change condition of the in-situ fluorescence emission intensity of the two structures before and after 500s under the laser radiation with different powers (0.1-0.7 mW) is measured.

Wherein the TCN-SFX amorphous film is prepared by directly dripping a molecular solution with the concentration of 8mM on a silicon wafer and drying the film at the temperature of 60 ℃ as the comparative example 1 of the embodiment 5;

wherein, the crystals with other shapes are obtained by quickly injecting 1mL of TCN-SFX tetrahydrofuran solution with the concentration of 8mM into a vigorously stirred sample bottle of 5mL of SDS aqueous solution by a reprecipitation method, stirring for 5 minutes, and standing for 72 hours at room temperature, specifically at 25 ℃, and the obtained four-leaf flower-shaped crystals are shown in FIG. 11, have the size of 6 +/-1 um, and are different from those in example 5 only in the growth environment temperature of the crystals;

compared with the test results of the TCN-SFX amorphous thin film shown in fig. 10a and the crystals with other morphologies shown in fig. 10b, the fractal crystals have better fluorescence luminescence stability as shown in fig. 10 c.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. However, the above description is only an example of the present invention, the technical features of the present invention are not limited thereto, and any other embodiments that can be obtained by those skilled in the art without departing from the technical solution of the present invention should be covered by the claims of the present invention.