Preparation method and application of excited state scintillator based on hybridization local-charge transfer

Abstract

The invention discloses a preparation method and application of an excited state scintillator based on hybrid local-charge transfer, and belongs to the technical field of organic functional materials. The excited state scintillator based on hybrid local-charge transfer overcomes the problems of weak X-ray absorption, low light yield and low X-ray imaging spatial resolution of the existing organic functional material, and widens the application of the HLCT organic fluorescent material in the aspect of X-ray imaging. The excited state scintillator based on hybrid localization-charge transfer is short in synthesis step, high in yield and novel in structure, interaction of heavy atoms-pi electrons in molecules is regulated and controlled through a space heavy atom strategy for the first time, and preparation of a material with an HLCT light-emitting mechanism is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of organic functional materials, and in particular to a preparation method and application of a hybrid localized-charge transfer excited state scintillator. Background Art

[0002] X-ray imaging technology has important applications in many fields such as medical diagnosis, defense industry, nuclear technology and radiation safety detection. Scintillators, as the core components in X-ray technology applications, can convert high-energy X-ray photons into low-energy visible light, thereby realizing X-ray detection and imaging. At present, most scintillator materials are inorganic materials synthesized by calcination under high temperature conditions. They are not only expensive, but also difficult to prepare on a large scale on flexible substrates. As a new type of scintillator material, organic scintillators have great potential application value in the field of flexible electronics. However, traditional pure organic materials are mainly composed of light elements such as carbon, hydrogen, and nitrogen, and have weak absorption of X-rays. Therefore, the triplet excitons with a generation ratio of 75% are not fully utilized, which limits the development of pure organic scintillator materials. Based on the above problems, researchers use organic room temperature phosphorescent materials and thermally activated delayed fluorescence to solve the problem of weak X-ray absorption, but these materials also face the problem that the triplet exciton lifetime is long and is not suitable for fast X-ray imaging. Thermal exciton materials have a short excited state lifetime, but their light yield and X-ray imaging spatial resolution are still low. Therefore, it is particularly necessary to develop organic functional materials with high light yield, low detection line, fast response time and high-definition resolution, and to provide new strategies for the development of flexible X-ray detectors for non-destructive radiation detection, medical imaging and other fields. Summary of the invention

[0003] The purpose of the present invention is to provide a preparation method and application of a hybrid localized-charge transfer excited state scintillator to solve the problems existing in the above-mentioned prior art.

[0004] The present invention obtains a novel high-efficiency organic scintillator (based on a hybrid localized charge transfer excited state scintillator) by modifying a heavy atom group on the basis of a hybrid localized charge transfer excited state (HLCT) material with benzothiadiazole as an acceptor and fluorene as a donor, and uses the novel high-efficiency organic scintillator for X-ray detection and imaging, thereby overcoming the problems of weak X-ray absorption, low light yield and low spatial resolution of X-ray imaging in existing organic functional materials, and broadening the application of HLCT organic fluorescent materials in X-ray imaging.

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

[0006] One of the technical solutions of the present invention is: a hybrid localized-charge transfer excited state scintillator, the structural formula of which is shown in formula (1) or formula (2):

[0007]

[0008] The compound of the formula (2) is formed by the polymerization of m units of the A structure and n units of the B structure; the connection order of the m units of the A structure and the n units of the B structure is not fixed;

[0009] The structure of A is:

[0010] The structure of B is:

[0011] The m is an integer of 0 to 500, n is an integer of 0 to 500, m and n are not 0 at the same time, and m+n=5 to 500;

[0012] Among them, R 1 and R 2 Each is independently selected from any one of a heavy atom-substituted C1-C12 alkyl group, a C1-C12 alkoxy group, a C6 aryl group, a C6-C12 aralkyl group, and a C6-C12 aralkyloxy group;

[0013] R 3 Any one selected from oxygen, sulfur, selenium, tellurium, and nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy containing or not containing a heavy atom;

[0014] R 4 Any one selected from hydrogen, fluorine, chlorine, bromine, iodine and oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy or propoxy.

[0015] Further, the heavy atom includes any one of chlorine, bromine, iodine, sulfur, phosphorus, arsenic, tellurium, selenium, silicon, and germanium;

[0016] The R 1 is n-hexyl bromide or methylmercapto; R 2 is bromo(methoxymethoxy)methoxymethane bromide or (2-iodoethoxy)benzene; R 3 is sulfur or 6-bromohexane-1-amine; R 4 It is methoxy or dimethylamine.

[0017] The second technical solution of the present invention is a method for preparing the above-mentioned hybrid localized-charge transfer excited state scintillator, comprising the following steps:

[0018] The preparation method of the compound of formula (1) comprises: mixing compound 1, a catalyst, a base and an organic solvent under a nitrogen atmosphere, then adding compound 2 and compound 3, mixing them evenly and heating them for reaction, and performing column chromatography separation after the reaction to obtain the hybrid localized-charge transfer excited state scintillator;

[0019] The compound 1 is:

[0020]

[0021] The compound 2 is:

[0022]

[0023] The compound 3 is:

[0024]

[0025] The preparation method of the compound of formula (2) comprises: mixing compound 1, a catalyst, a base and an organic solvent under a nitrogen atmosphere, then adding compound 4 and compound 5, mixing evenly and heating to react, and performing Soxhlet extraction after the reaction to obtain the hybrid localized-charge transfer excited state scintillator;

[0026] The compound 4 is:

[0027]

[0028] The compound 5 is:

[0029]

[0030] As mentioned above, R 1 and R 2 Each is independently selected from any one of a heavy atom-substituted C1-C12 alkyl group, a C1-C12 alkoxy group, a C6 aryl group, a C6-C12 aralkyl group, and a C6-C12 aralkyloxy group;

[0031] R 3 Any one selected from oxygen, sulfur, selenium, tellurium, and nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy containing or not containing a heavy atom;

[0032] R 4 Any one selected from hydrogen, fluorine, chlorine, bromine, iodine and oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy or propoxy;

[0033] The X is chlorine, bromine or iodine.

[0034] Further, the catalyst includes tetrakis-(triphenylphosphine)palladium(0);

[0035] The base includes K 2 CO 3 ;

[0036] The organic solvent includes toluene and methanol in a volume ratio of (2-5):(1-2).

[0037] Furthermore, the heating reaction is carried out at a temperature of 50 to 120° C. and for a time of 12 to 24 hours.

[0038] The third technical solution of the present invention: an application of the above-mentioned hybrid localized-charge transfer excited state scintillator as a non-destructive radiation detection material or medical imaging material.

[0039] Furthermore, the medical imaging material comprises an X-ray imaging material.

[0040] Technical solution four of the present invention: A flexible X-ray detector, the preparation raw materials of which include the above-mentioned hybrid localized-charge transfer excited state scintillator.

[0041] Organic scintillators are a type of organic material that can emit light after absorbing high-energy particles or rays. There are mainly the following physical processes: When the organic scintillator material is excited by X-rays, the high-energy X-ray photons have enough energy to ionize the molecules in the material and produce high-energy electrons. These high-energy electrons collide with other molecules in the material and transfer energy to more molecules through non-radiative transitions, generating secondary and tertiary electrons until the electron energy drops to about 2 to 4 times the band gap. In this excited state, localized excitons are formed between charges under radiation coupling. Over time and under the influence of physical and chemical processes within the molecules, these excited states will eventually recombine and release photons.

[0042] The present invention introduces a connection form of a substituent having a heavy atom into the σ bond on the carbon atom at the 9th position of fluorene, thereby greatly improving the luminous efficiency, Stokes shift, fluorescence lifetime, absorption cross section, luminescence spectrum broadening and other properties of an organic scintillator (based on a hybrid localized-charge transfer excited state scintillator). The light yield, detection line, response time and resolution of the organic scintillator are also improved, and thus it has very important significance.

[0043] The present invention discloses the following technical effects:

[0044] (1) The hybrid localized charge transfer excited state scintillator of the present invention overcomes the problems of weak X-ray absorption, low light yield and low spatial resolution of X-ray imaging existing in existing organic functional materials, and broadens the application of HLCT organic fluorescent materials in X-ray imaging.

[0045] (2) The synthesis steps of the hybrid localized charge transfer excited state scintillator of the present invention are short, the yield is high, and the structure is novel. For the first time, the interaction between heavy atoms and π electrons in molecules is regulated by the strategy of spatial heavy atoms, thus realizing the preparation of materials with HLCT luminescence mechanism.

[0046] (3) The novel HLCT organic scintillator (based on hybrid localized-charge transfer excited state scintillator) of the present invention has a fast reverse intersystem crossing of high triplet-singlet energy levels (2.63×10 8 s -1 ), large Stokes shift (>100nm), short triplet exciton lifetime (3.74ns), and excellent fluorescence quantum yield (100%); and exhibits a very narrow X-ray emission spectrum with a half-maximum full width of 56nm, a high light yield of about 42400 photons / MeV, and a low detection limit of 84.6nGy s -1 , can achieve 40.5lp per mm -1 The high X-ray imaging resolution can overcome the shortcomings of existing organic scintillators, provide a feasible strategy for realizing new stable and efficient organic scintillators, and has broad application prospects in the fields of X-ray detection and imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 The optical properties of organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 of the present invention, wherein a is the ultraviolet absorption and emission spectra of the thin films prepared using the organic substances A, B, C and D, b is the transient fluorescence lifetime decay curve of the thin films prepared using the organic substances A, B, C and D, c is the X-ray absorption curve of the thin films prepared using the organic substances A, B, C and D, and d is the X-ray excitation spectrum and light yield of the thin films prepared using the organic substances A, B, C and D and the reference CSI:T1.

[0049] Figure 2The radiation luminescence intensity of organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 of the present invention at different X-ray dose rates, wherein a is a film prepared using organic substance A prepared in Example 1, b is a film prepared using organic substance B prepared in Example 2, c is a film prepared using organic substance C prepared in Example 3, and d is a film prepared using organic substance D prepared in Example 4.

[0050] Figure 3 Modulation transfer function (MTF) and spatial resolution of X-ray slanted edge images of organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 of the present invention, wherein a is a film prepared by organic substance A prepared in Example 1, b is a film prepared by organic substance B prepared in Example 2, c is a film prepared by organic substance C prepared in Example 3, and d is a film prepared by organic substance D prepared in Example 4.

[0051] Figure 4 Bright field and dark field photographs of the pen and the pen core before and after X-ray exposure of organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 of the present invention. DETAILED DESCRIPTION

[0052] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0053] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0054] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0055] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0056] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0057] In a first aspect, the present invention provides a hybrid localized charge transfer excited state scintillator, the structural formula of which is shown in formula (1) or formula (2):

[0058]

[0059]

[0060] The compound of the formula (2) is formed by the polymerization of m units of the A structure and n units of the B structure;

[0061] The structure of A is:

[0062] The structure of B is:

[0063] The m is an integer of 0 to 500, n is an integer of 0 to 500, m and n are not 0 at the same time, and m+n=5 to 500;

[0064] Among them, R 1 and R 2 Each is independently selected from any one of a heavy atom-substituted C1-C12 alkyl group, a C1-C12 alkoxy group, a C6 aryl group, a C6-C12 aralkyl group, and a C6-C12 aralkyloxy group;

[0065] R 3 Any one selected from oxygen, sulfur, selenium, tellurium, and nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy containing or not containing a heavy atom;

[0066] R 4 Any one selected from hydrogen, fluorine, chlorine, bromine, iodine and oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy or propoxy.

[0067] The heavy atoms in the present invention include any one of chlorine, bromine, iodine, sulfur, phosphorus, arsenic, tellurium, selenium, silicon, and germanium; R 1 is n-hexyl bromide or methylmercapto; R 2 is bromo(methoxymethoxy)methoxymethane bromide or (2-iodoethoxy)benzene; R 3 is sulfur or 6-bromohexane-1-amine; R 4 It is methoxy or dimethylamine.

[0068] In a second aspect, the present invention provides a method for preparing the above-mentioned hybrid localized-charge transfer excited state scintillator, comprising the following steps:

[0069] The preparation method of the compound of formula (1) comprises: mixing compound 1, a catalyst, a base and an organic solvent under a nitrogen atmosphere, then adding compound 2 and compound 3, mixing evenly and heating to react, and performing column chromatography separation after the reaction to obtain a hybrid localized-charge transfer excited state scintillator;

[0070] Compound 1 is:

[0071]

[0072] Compound 2 is:

[0073]

[0074] Compound 3 is:

[0075]

[0076] The chemical reaction equation is as follows:

[0077]

[0078] The preparation method of the compound of formula (2) comprises: mixing compound 1, a catalyst, a base and an organic solvent under a nitrogen atmosphere, then adding compound 4 and compound 5, mixing evenly and heating to react, and performing Soxhlet extraction after the reaction to obtain a hybrid localized-charge transfer excited state scintillator;

[0079] Compound 4 is:

[0080]

[0081] Compound 5 is:

[0082]

[0083] The chemical reaction equation is as follows:

[0084]

[0085] R 1 and R 2 Each is independently selected from any one of C1-C12 alkyl, C1-C12 alkoxy, C6 aryl, C6-C12 aralkyl, and C6-C12 aralkyloxy substituted with a heavy atom; the heavy atom includes any one of chlorine, bromine, iodine, sulfur, phosphorus, arsenic, tellurium, selenium, silicon, and germanium;

[0086] R 3 Any one selected from oxygen, sulfur, selenium, tellurium, and nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy containing or not containing a heavy atom;

[0087] R 4 Any one selected from hydrogen, fluorine, chlorine, bromine, iodine and oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy or propoxy;

[0088] X is chlorine, bromine or iodine; m is an integer of 0 to 500, n is an integer of 0 to 500, m and n are not 0 at the same time, and m+n=5 to 500.

[0089] The organic solvent used in the present invention comprises toluene and methanol in a volume ratio of (2-5):(1-2).

[0090] The heating reaction temperature of the present invention is 50-120° C. and the time is 12-24 hours.

[0091] The third aspect of the present invention provides an application of the above-mentioned hybrid localized-charge transfer excited state scintillator as a non-destructive radiation detection material or a medical imaging material.

[0092] In a fourth aspect, the present invention provides a flexible X-ray detector, wherein the raw materials for preparing the detector include the above-mentioned hybrid localized-charge transfer excited state scintillator.

[0093] Example 1

[0094] A preparation method based on hybrid localized-charge transfer excited state scintillator (organic matter A):

[0095] Under nitrogen atmosphere, 5,6-dimethoxy-4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzo[c][1,2,5]thiadiazole (448 mg, 1 mmol), tetrakis-(triphenylphosphine)palladium(0) (16 mg, 0.0144 mol), 2MK 2 CO 3(6 mL) and toluene / methanol (5 mL / 1 mL) were added to a 50 mL three-necked flask and mixed evenly, and then 9,9-bis(((bromomethoxy)methoxy)-2-iodo-9H-fluorene (693 mg, 1.1 mmol) and 2-bromo-9,9-bis(6-bromohexyl)-9H-fluorene (571 mg, 1.1 mmol) were added and heated to 80 ° C for 12 hours. After cooling to room temperature, the reaction mixture was diluted with ether and the organic phase was washed with brine. MgSO 4 After drying, the solvent was removed. The crude product was subjected to silica gel column chromatography (using dichloromethane: petroleum ether, 1:5-10, v / v) to remove impurities, and recrystallized from dichloromethane / ethanol (1:10, v / v) to obtain a green product, which is a hybrid localized-charge transfer excited state scintillator, with a product yield of 55%.

[0096] The chemical reaction equation is as follows:

[0097]

[0098] 1 H NMR (500 MHz, CDCl 3 )δ8.09(s,10H),8.06-7.84(m,21H),7.78(s,10H),7.63-7.28(m,21H),7.34(s,9H),7.34(s,8H),7.24(s,5H),5 .50(s,20H),4.50(s,40H),3.92(s,30H),3.52(s,10H),1.93(s,17H),1.82(s,8H),1.33(s,31H),1.26(s,21H). 13 C NMR (126 MHz, CDCl 3 )δ158.03,155.74,150.34,150.16,142.39,142.21,138.53,138.40,137.29,135. 32,133.48,131.97,130.37,129.29,128.78,127.95,125.80,123.77,123.48,122 .76,120.78,120.64,120.52,120.20,119.03,118.43,110.48,106.17,94.21,90. 38,60.70,52.54,40.16,33.30,31.58,30.68,29.54,25.54.HRMS(m / z)calcd.forC 52 H 56 Br 4 N 2 O8 S[M]+:1184.0491; found:1184.0477.

[0099] Example 2

[0100] A preparation method based on hybrid localized-charge transfer excited state scintillator (organic matter B):

[0101] Under nitrogen atmosphere, 2-(6-bromohexyl)-N5,N5,N6,N6-tetramethyl-4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2H-benzo[d][1,2,3]triazole-5,6-diamine (620 mg, 1 mmol), tetrakis-(triphenylphosphine)palladium(0) (16 mg, 0.0144 mol), 2M K 2 CO 3 (6mL) and toluene / methanol (2-5mL / 1-2mL) were added to a 50mL three-necked flask and mixed evenly, and then 2,7-dibromo-9,9-bis(4-(2-iodoethoxy)phenyl)-9H-fluorene (898mg, 1.1mmol) and (2,7-dibromo-9H-fluorene-9,9-diyl)bis(methylsulfane) (458mg, 1.1mmol) were added and heated to 80°C for 12 hours. After cooling to room temperature, the reaction mixture was diluted with ether and the organic phase was washed with brine. MgSO 4 After drying, the solvent was removed. The crude product was reprecipitated from ethanol, and n-hexane was used as the extraction solvent. The impurities were further purified by Soxhlet extraction to obtain a hybrid localized-charge transfer excited state scintillator with a product yield of 52%.

[0102] The chemical reaction equation is as follows:

[0103]

[0104] Herein, m is an integer of 0 to 500, n is an integer of 0 to 500, and m+n=5 to 500.

[0105] 1 H NMR (500 MHz, CDCl 3 )δ8.10-7.73(m)7.30-7.20(m),6.83-6.78(m),4.50-4.06(m),3.68-3.50(m),2.98-2.13(m),1.94-1.32(m).Mw:12.3kDa,PDI:1.56.

[0106] Example 3

[0107] A preparation method based on hybrid localized-charge transfer excited state scintillator (organic matter C):

[0108] Under nitrogen atmosphere, 5,6-difluoro-4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzo[c][1,2,5]selenoimidazole (471 mg, 1 mmol), tetrakis-(triphenylphosphine)palladium(0) (16 mg, 0.0144 mol), 2MK 2 CO 3 (6 mL) and toluene / methanol (5 mL / 1 mL) were added to a 50 mL three-necked flask and mixed evenly, and then (2-bromo-9H-fluorene-9,9-diyl)bis(4,1-phenylene))bis(trimethylgermane (1388 mg, 2.2 mmol) was added and heated to 80 °C for 12 hours. After cooling to room temperature, the reaction mixture was diluted with ether and the organic phase was washed with brine. MgSO 4 After drying, the solvent was removed. The crude product was subjected to silica gel column chromatography (using dichloromethane: petroleum ether, 1:5-10, v / v) to remove impurities, and recrystallized from dichloromethane / ethanol (1:10, v / v) to obtain a green product, which is a hybrid localized-charge transfer excited state scintillator, with a product yield of 82%.

[0109] The chemical reaction equation is as follows:

[0110]

[0111] 1 H NMR (500MHz, CDCl3) δ8.11-7.72(m,3H),7.58(s,1H),7.34(d,J=6.4Hz,5H),7.24(s,1H),7.20(s,1H),7.16(s,4H),1.33(s,18H). 13 C NMR (125MHz, CDCl3) δ163.84,148.82,147.21,147.07,138.34,137.06,134.67,129.58,126.88,126.88,124.79,122.86,119. 49,119.08,116.63,109.16,67.21,34.58,31.36.HRMS(m / z)calcd.forC68H66F2Ge4N2Se[M]+:1324.1206; found:1324.1209.

[0112] Example 4

[0113] A preparation method of a hybrid localized charge transfer excited state scintillator (organic matter D): 2-isopropyl-4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2H-benzo[d][1,3,2]diazophosphoryl (430 mg, 1 mmol), tetrakis-(triphenylphosphine)palladium(0) (16 mg, 0.0144 mol), 2M K 2 CO 3 (6mL) and toluene / methanol (2-5mL / 1-2mL) were added to a 50mL three-necked flask and mixed evenly, then ((2,7-dibromo-9H-fluorene-9,9-diyl)bis(4,1-phenylene)bis(propane-3,1-diyl))bis(dimethylarsane) (768mg, 1mmol) was added and heated to 80°C for 12 hours. After cooling to room temperature, the reaction mixture was diluted with ether and the organic phase was washed with brine. MgSO 4 After drying, the solvent was removed. The crude product was reprecipitated from ethanol, and n-hexane was used as the extraction solvent. The impurities were further purified by Soxhlet extraction to obtain a hybrid localized-charge transfer excited state scintillator with a product yield of 52%.

[0114] The chemical reaction equation is as follows:

[0115]

[0116] Here, n is an integer from 5 to 500.

[0117] 1 H NMR (500 MHz, CDCl 3 )δ8.14-7.70(m)7.34-7.21(m),6.82-6.75(m),4.55-4.01(m),3.66-3.52(m),2.96-2.11(m),1.99-1.37(m).Mw:14.2kDa,PDI:1.61.

[0118] Effect Example 1

[0119] The optical properties of organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 are shown in Figure 1 , Figure 1 In the figure, a is the ultraviolet absorption and emission spectra of the thin films (scintillator films) prepared using organic substances A, B, C and D, b is the transient fluorescence lifetime decay curve of the thin films prepared using organic substances A, B, C and D, c is the X-ray absorption curve of the thin films prepared using organic substances A, B, C and D, and d is the X-ray excitation spectrum and light yield of the thin films prepared using organic substances A, B, C and D and the reference CSI:T1.

[0120] from Figure 1 As can be seen in Figure a, the main absorption peaks of the UV-visible absorption spectra of organic compounds A, B, C and D are around 420nm; the emission peaks of the fluorescence spectra of organic compounds A, B, C and D are 508-539nm respectively. This shows that these organic compounds have large Stokes shifts and thus small self-absorption.

[0121] from Figure 1 As can be seen in Figure b, organic compounds A, B, C and D decay in a single exponential manner in the nanosecond range of 3 to 5 ns, which indicates that organic compounds A, B, C and D are very conducive to rapid X-ray imaging.

[0122] from Figure 1 As can be seen in Figure c, organic compounds A, B, C and D have a large absorption cross section due to the introduction of heavy atoms, which is beneficial to the absorption of X-rays.

[0123] from Figure 1 As can be seen in Figure d, the half-peak widths of organic compounds A, B, C, and D are all less than 70nm, indicating that they have good narrow emission properties. At the same time, their light yields calculated by comparing with the reference scintillator are 35,000 to 42,400 photons / MeV, indicating that they all have high light yields.

[0124] The above scintillator films were prepared by the same melt quenching technique. 500 mg of organic matter (organic matter A, B, C or D) was transferred into a beaker and heated at 160°C until the raw material melted and the bubbles disappeared. Subsequently, the liquid organic matter in the beaker was poured into a graphite mold and rapidly cooled at room temperature to form a film with a thickness of about 300 microns and a diameter of more than 10 centimeters.

[0125] Effect Example 2

[0126] The organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 were made into thin films and the radiation luminescence intensity of different films at different X-ray dose rates was measured. The results are shown in Figure 2 , wherein a is a film prepared using organic substance A prepared in Example 1, b is a film prepared using organic substance B prepared in Example 2, c is a film prepared using organic substance C prepared in Example 3, and d is a film prepared using organic substance D prepared in Example 4.

[0127] from Figure 2 Figures a, b, c and d show that the luminescence intensity of organic matter A, B, C and D changes linearly at different X-ray dose rates. The minimum detection limit calculated from the luminescence intensity of 3000 is 85-450 μGy s -1 , indicating that they have high X-ray detection sensitivity.

[0128] Effect Example 3

[0129] The organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 were made into thin films and the modulation transfer function (MTF) and spatial resolution of the X-ray tilted edge images of the different films were measured. The results are shown in Figure 3 , wherein a is a film prepared using organic substance A prepared in Example 1, b is a film prepared using organic substance B prepared in Example 2, c is a film prepared using organic substance C prepared in Example 3, and d is a film prepared using organic substance D prepared in Example 4.

[0130] from Figure 3 As can be seen from Figures a, b, c and d, the X-ray imaging spatial resolution of the films prepared by organic materials A, B, C and D is 31.9-40.5 lp mm when the modulation transfer function (MTF) of the X-ray tilted edge image is 0.2. -1 , indicating that they all have very excellent X-ray imaging spatial resolution and can be used for practical high-resolution X-ray imaging.

[0131] Effect Example 4

[0132] The organic substances A, B, C and D prepared in Examples 1, 2, 3 and 4 were made into thin films and the bright field and dark field photographs of the pen and the pen core before and after X-ray exposure were measured for different films (dose rate, 2.023 mGy s -1 ), the results are shown in Figure 4 .

[0133] Figure 4 The results of imaging tests of organics A, B, C and D are shown to demonstrate their practical value. A pen equipped with a spring in different states was placed between an X-ray source and a film of organics A, B, C and D. The outline of the originally invisible spring is clearly presented on the film, while the plastic shell is almost transparent, further demonstrating the great potential of this type of HLCT scintillator in X-ray radiography.

[0134] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A hybrid localized-charge transfer excited state scintillator, characterized in that: The structural formula is shown in formula (1) or formula (2): Wherein, R1 and R2 are each independently selected from any one of a heavy atom-substituted C1-C12 alkyl group, a C1-C12 alkoxy group, a C6 aryl group, a C6-C12 aralkyl group, and a C6-C12 aralkyloxy group; R3 is selected from any one of oxygen, sulfur, selenium, tellurium, and nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy containing or not containing a heavy atom; R4 is selected from any one of hydrogen, fluorine, chlorine, bromine, iodine, and oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy; m is an integer of 0 to 500, n is an integer of 0 to 500, m and n are not 0 at the same time, and m+n=5 to 500.

2. The hybrid localized-charge transfer excited state scintillator according to claim 1, characterized in that: The heavy atom includes any one of chlorine, bromine, iodine, sulfur, phosphorus, arsenic, tellurium, selenium, silicon, and germanium; The R1 is n-hexyl bromide or methylmercapto; R2 is bromo(methoxymethoxy)methoxymethane bromide or (2-iodoethoxy)benzene; R3 is sulfur or 6-bromohexane-1-amine; and R4 is methoxy or dimethylamine.

3. A method for preparing a hybrid localized-charge transfer excited state scintillator according to any one of claims 1 to 2, characterized in that: The following steps are involved: The preparation method of the compound of formula (1) comprises: mixing compound 1, a catalyst, a base and an organic solvent under a nitrogen atmosphere, then adding compound 2 and compound 3, mixing evenly and heating to react, and performing column chromatography separation after the reaction to obtain the hybrid localized-charge transfer excited state scintillator; The compound 1 is: The compound 2 is: The compound 3 is: The preparation method of the compound of formula (2) comprises: mixing compound 1, a catalyst, a base and an organic solvent under a nitrogen atmosphere, then adding compound 4 and compound 5, mixing evenly and heating to react, and performing Soxhlet extraction after the reaction to obtain the hybrid localized-charge transfer excited state scintillator; The compound 4 is: The compound 5 is: Said R1 and R2 are each independently selected from any one of a heavy atom-substituted C1-C12 alkyl group, a C1-C12 alkoxy group, a C6 aryl group, a C6-C12 aralkyl group, and a C6-C12 aralkyloxy group; R3 is selected from any one of oxygen, sulfur, selenium, tellurium, and nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy containing or not containing a heavy atom; R4 is selected from any one of hydrogen, fluorine, chlorine, bromine, iodine, and oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus, and arsenic containing a substituent; the substituent is methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, 2,6-diisopropylphenyl, methoxy, ethoxy, or propoxy; The X is chlorine, bromine or iodine.

4. The preparation method according to claim 3, characterized in that: The catalyst includes tetrakis-(triphenylphosphine)palladium(0); The base comprises K2CO3; The organic solvent includes toluene and methanol in a volume ratio of (2-5):(1-2).

5. The preparation method according to claim 3, characterized in that: The temperature of the heating reaction is 50-120° C. and the time is 12-24 hours.

6. Use of the hybrid localized-charge transfer excited state scintillator according to any one of claims 1 to 2 as a non-destructive radiation detection material or a medical imaging material.

7. A flexible X-ray detector, characterized in that: The preparation raw materials include the hybrid localization-charge transfer excited state scintillator according to any one of claims 1 to 2.

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