CN113308129B

CN113308129B - Homogeneous polycrystalline symmetrical bis (tetraphenylethylene) fluorescent compound preparation method and crystal thereof

Info

Publication number: CN113308129B
Application number: CN202010118474.1A
Authority: CN
Inventors: 杨琴; 吴江; 阎斌
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2020-02-26
Filing date: 2020-02-26
Publication date: 2022-01-14
Anticipated expiration: 2040-02-26
Also published as: CN113308129A

Abstract

The invention discloses a method for simply preparing fluorescent compounds of tetracene vinyl sulfoxide and tetracene vinyl sulfone with polymorphism. Diphenyl borate thioether easy to synthesize and triphenylbromoethylene are used as raw materials to react to obtain a bis-tetraphenyl vinyl sulfide compound, and then two fluorescent compounds, namely bis-tetraphenyl vinyl sulfoxide and bis-tetraphenyl vinyl sulfone, are respectively obtained by controlling the using amount of an oxidant. By recrystallization from different solvents and heating at different temperatures, the bis (tetraphenylvinyl sulfoxide) and bis (tetraphenylvinyl sulfone) can give crystals of two or more stacking modes, each of which has a different fluorescence color and abrasive properties. The invention is beneficial to researching the relation between different stacking modes and performances of the crystal. The method has the advantages of mild reaction conditions, simple operation, high synthesis efficiency and the like.

Description

Homogeneous polycrystalline symmetrical bis (tetraphenylethylene) fluorescent compound preparation method and crystal thereof

Technical Field

The invention discloses a simple preparation method for obtaining two fluorescent compounds of tetracene vinyl sulfoxide and tetracene vinyl sulfone with polymorphism. Diphenyl borate thioether easy to synthesize and triphenylbromoethylene are used as raw materials to react to obtain a bis-tetraphenyl vinyl thioether compound, and then the bis-tetraphenyl vinyl sulfoxide and the bis-tetraphenyl vinyl sulfone fluorescent compounds are respectively oxidized by controlling the using amount of an oxidizing agent. By recrystallization from different solvents and heating at different temperatures, the bis-tetraphenylvinylsulfoxide and bis-tetraphenylvinylsulfone can be obtained as two and three bulk-mode crystals, respectively. The optical properties of the various crystals differ. The method has the advantages of simple operation, high yield and the like.

Background

Currently, organic fluorescent materials have attracted attention from a large number of researchers due to their high emission efficiency in a solid or aggregated state. Organic fluorescent materials have been widely used in various fields such as OLEDs, biological probes, chemical sensors, etc. (j.mei, n.l.c.leung, r.t.k.kwok, j.w.y.lam and b.z.tang, chem.rev.,2015,115, 11718-. However, most organic fluorescent compounds emit light in solution, and fluorescence quenching occurs in an aggregated state due to nonradiative transition caused by pi-pi stacking, a phenomenon known as aggregation-induced quenching (ACQ). The use of organic materials in the solid phase is largely limited due to the effects of the ACQ effect. Fortunately, the task group of the Tang-Council college in 2001 discovered a phenomenon that is completely opposite to that of ACQ. They found that Hexaphenylsilyl (HPS) did not emit light in solution, but emitted light strongly in the aggregated state. This phenomenon, called aggregation-induced emission (AIE), is quite opposite to the quenching (ACQ) effect caused by aggregation of traditional chromophores. (Luo J, Xie Z, Lam JWY, Cheng L, Chen H, Qiu C, et al. chem Commun 2001: 1740-1.) the organic fluorescent material with AIE effect has shown wide application prospect in the fields of photoelectricity, sensing, biology and the like.

According to the literature, the luminescence of organic fluorescent materials is related to the stacking mode of the solid, (X.Luo, J.Li, C.Li, L.Heng, Y.Q.Dong, Z.Liu, Z.Bo and B.Z.Tang, adv.Mater.,2011,23, 3261-plus 3265; Y.Wang, D.Xu, H.Gao, et al, J.Phys.chem.C,2018,122, 2297-plus 2306; W.Yang, C.Liu, S.Lu, et al, J.Mater.chem.C,2018,6, 290-plus 298), and the current methods for changing the molecular stacking mode mainly include physical methods such as heating, grinding, smoking (Z.Yang, Z.Chi, Z.Mao, et al, Mater.chem.Front.,2, 861 890). However, these methods cannot explain the principle of mechanical mill luminescence from the molecular level, and therefore the relationship between molecular packing and optical properties can be explained only by the polymorphism-based luminescence. Although there are many reports in the literature of differences in the optical properties of polymorphic compounds (h.sun, s. -s.sun, f. -f.han, z. -h.ni, r.zhang and m. -d.li, j.mater. chem.c,2019,7,7053-7060.) there is still no accurate guidance on how to design molecules that can be characterized as multi-colored mechanical milling.

Tetraphenylethylene (TPE), one of the most classical AIE units, has been widely used as an important component of high efficiency luminescent materials. Tetraphenylethylene derivatives have been widely studied for their easy synthesis, flexible structure and excellent photophysical properties. Furthermore, it is known that tetraphenylethylene units have a distorted molecular structure, which favours the formation of mechanical discolouration phenomena. The modification and utilization of tetraphenylethylene have potential development prospects, and tetraphenylethylene can be modified by adding other groups.

Disclosure of Invention

The invention adopts a simple method to synthesize the bis (tetraphenyl) vinyl sulfoxide and the bis (tetraphenyl) vinyl sulfone. Both of these fluorescent compounds have polymorphic characteristics, and the properties of each form differ.

The technical scheme of the invention is as follows:

the molar ratio of the substrate to the oxidant is 1:1-1:2.2

The temperature of the oxidation reaction is 0-25 ℃.

The reaction time of the oxidation is 0.5-24 h.

The oxidant is one or two of hydrogen peroxide, m-chloroperoxybenzoic acid, trifluoroacetic acid, hydrogen peroxide and the like.

The solvent for the oxidation reaction is one or two mixed solvents of toluene, dichloromethane, THF, diethyl ether and acetone.

The structures of organic fluorescent dyes 1 and 2 were determined by nuclear magnetic resonance and high resolution mass spectrometry.

Good solvents such as dichloromethane, trichloromethane, acetonitrile and tetrahydrofuran are selected to volatilize and prepare single crystals or good solvents are selected to dissolve dyes, and poor solvents are mixed to prepare single crystals.

Fluorescence emission spectrum research shows that the luminescent colors of the two crystal structures of the organic fluorescent dye 1 are blue and green respectively; the emission colors of the three crystal structures of the organic fluorescent dye 2 are blue, green and blue, respectively.

The research of an X-ray diffraction spectrogram shows that the organic fluorescent dye 1 has two crystal forms, the organic fluorescent dye 2 has three crystal forms, and each crystal form of the two organic fluorescent dyes has mechanical grinding performance.

These properties show that the organic fluorescent dye has good application value in the aspects of temperature control sensors, fluorescent probes, anti-counterfeiting and the like.

Drawings

FIG. 1 is an X-ray diffraction pattern of three stacking modes of Compound 2 prepared according to the present invention.

FIG. 2 shows fluorescence emission spectra of compound 2 prepared by the present invention in three stacking modes.

FIG. 3 is an X-ray diffraction pattern of compound 2W prepared in accordance with the present invention after milling to an amorphous state.

Fig. 4 is an X-ray diffraction pattern of compound 2W prepared in accordance with the present invention after milling and conversion to an amorphous state, followed by fumigation with methanol.

FIG. 5 shows the fluorescence emission spectrum of compound 2W prepared by the present invention after milling and transforming into amorphous state.

Fig. 6 is a fluorescence emission spectrum of compound 2W prepared by the present invention after milling and transforming into amorphous state, and then fumigating with methanol.

Detailed Description

The following examples are provided to aid in the further understanding of the present invention, but the invention is not limited thereto.

Example 1

Synthesis of Compound 1: under nitrogen, 1a (2g,4.56 mmol), triphenylbromoethylene (6.12g,18.26mmol) and Pd (PPh) were charged in a 250mL three-necked flask₃)₄(421mg, 8% mmol). Then 100mL of toluene, K is added₂CO₃The solution (2M,40mL) was heated to 100 ℃ and refluxed for 24 h. After cooling to room temperature, the solution was removed, the residue was washed with 100mL of methylene chloride and the organic layer was washed with 100mL of saturated brine and then Na₂SO₄Drying, desolventizing and recrystallizing. Intermediate i (1.78g, 56% yield) was obtained. Intermediate i (1g,1.4mmol) was dissolved in 50mL of dichloromethane and m-chloroperoxybenzoic acid (85%, 284mg,1.4mmol) was added under ice bath conditions to complete the reaction and work up to give compound 1(0.77g, 75% yield).

¹H NMR(400MHz,CDCl₃)δ7.21(s,1H),7.18(d,J＝7.3Hz,2H), 7.06–7.01(m,8H),6.99–6.92(m,6H),6.88(dd,J＝7.8,1.5Hz,2H).¹³C NMR (100MHz,CDCl₃)δ147.1,143.2,143.1,143.06,143.02,142.75,139.7,132.2, 131.38,131.33,128.0,127.9,127.85,127.0,126.9,124.7.HR-MS(ESI):m/z＝ 710.2593,calcd.For C52H38SO[M+H]+:710.2597。

Example 2

Synthesis of Compound 2 intermediate i (1g,1.4mmol) was dissolved in 50mL of dichloromethane, and m-chloroperoxybenzoic acid (85%, 629.5mg,3.1mmol) was added under ice-bath conditions, followed by workup after completion of the reaction to give Compound 2(0.86g, 82% yield).

¹H NMR(400MHz,CDCl₃)δ7.50(d,J＝8.4Hz,2H),7.18(s,1H), 7.10–6.98(m,10H),6.96–6.84(m,6H).¹³C NMR(100MHz,CDCl₃)δ149.3, 143.5,143.01,142.82,142.81,139.2,139.1,132.1,131.4,131.3,128.11,128.07, 127.9,127.3,127.12,127.09,127.07.HR-MS(ESI):m/z＝726.2593,calcd. for C52H38SO2[M+H]+:726.2610

In CH₂Cl₂Recrystallizing in MeOH mixed solvent to obtain unstable single crystal 2, heating at 50 deg.C for 30min, volatilizing dichloromethane to obtain green crystal 2G, heating at 100 deg.C for 30min to obtain white crystal 2W.

As shown in fig. 1, X-ray diffraction shows that sharp diffraction peaks of 2, 2G and 2W appear at different positions, and the three stacking modes are on the surface, indicating that the fluorescent dye 2 has polymorphism.

As shown in FIG. 2, when the three kinds of crystals were irradiated with 325nm light, single crystal 2 emitted blue fluorescence, 2G emitted green fluorescence, and 2W emitted blue fluorescence.

The three different crystal forms all have mechanical grinding performance, taking 2W as an example, after the 2W is subjected to mechanical force effects such as grinding, extrusion and the like, X-ray diffraction analysis is carried out, and the spectrum is shown in figure 3, wherein a sharp diffraction peak is weakened or even disappears, which shows that the fluorescent dye can be converted from a crystalline state to an amorphous state. 2W after being smoked and ground by methanol, and then X-ray diffraction analysis is carried out, the atlas of the atlas is shown in figure 4, and a sharp diffraction peak appears again, which shows that the fluorescent dye can return to the crystalline state from the amorphous state. Indicating that 2W has reversible mechanical abrasion properties. As shown in FIG. 5, the color of the 2W emitted light after polishing changed from blue to green under the irradiation of the excitation light at 340 nm. Further, 2W in the amorphous state was smoked with methanol, and the amorphous state was transformed into the crystalline state, and blue fluorescence was emitted again, as shown in FIG. 6.

Claims

1. A method of synthesizing a fluorescent compound, comprising: the method comprises the following steps:

adding 1a, triphenyl bromoethylene and tetratriphenyl phosphorus palladium under the protection of nitrogen, wherein the solvents are toluene and K₂CO₃Heating the solution to100 ^oC, refluxing for 24 hours, and performing post-treatment to obtain a target compound i;

dissolving the compound i in a solvent, adding different amounts of oxidants for oxidation, and performing post-treatment to obtain the bis (tetraphenyl) vinyl sulfoxide 1 and bis (tetraphenyl) vinyl sulfone 2,

2. a method of synthesizing a fluorescent compound according to claim 1, wherein: the molar ratio of substrate to oxidant is different; the oxidant is one of hydrogen peroxide, trifluoroacetic acid and m-chloroperoxybenzoic acid; the oxidation reaction temperature is 0-25 deg.C^oC; the reaction time of oxidation is 0.5-2 h; the solvent is any one of tetrahydrofuran, toluene and dichloromethane.

3. A method of synthesizing a fluorescent compound according to claim 2, wherein: during recrystallization, the solvent selected is one or more of dichloromethane, ethyl acetate, acetonitrile and tetrahydrofuran.

4. A method of synthesizing a fluorescent compound according to claim 3, wherein: bis (tetraphenyl) vinyl sulfoxide at 120^oHeating for 1 h to obtain a crystal 1W which is white in appearance and emits blue fluorescence, and heating the white crystal at 163^oC, heating for 1 h to obtain a crystal 1G which is green and emits green fluorescence, wherein the two states have mechanical grinding performance; bis (tetraphenylvinylsulfone) in mixed solvent of dichloromethane and methanolGrowing a colorless single crystal 2 which emits blue fluorescence in appearance at 50^oC, heating for 30min to obtain a crystal 2G which is green and emits green fluorescence; the green crystals are then at 100^oC heating for 30min to obtain another crystal 2W with white appearance and blue fluorescence, wherein the three states have mechanical grinding performance.