Organic scintillator with X-ray response, liquid crystal film and application thereof

Abstract

The invention discloses an organic scintillator with X-ray response, a liquid crystal film and application thereof, and belongs to the technical field of photoluminescent materials. An organic scintillator with X-ray response and C6M are blended and polymerized to prepare the transparent polymer liquid crystal film with high flexibility, the film shows green emission characteristics under photoluminescence and radiation luminescence conditions, and the X-ray imaging sensitivity and resolution of the film are remarkably improved. Experiments show that the resolution ratio of the prepared film under a standard line pair card reaches 20LP / mm, and complex images such as a chip internal structure and a fish body skeleton frame can be clearly presented. The preparation method has the advantages of few reaction steps and low cost, supports multi-element scintillator doping regulation and control, and is suitable for high-yield film preparation and various imaging scenes.

Description

Technical Field

[0001] The invention belongs to the technical field of photoluminescent materials, and in particular relates to an organic scintillator with X-ray response, a liquid crystal film and applications thereof. Background Art

[0002] In recent years, X-ray detection technology has been widely used in medicine, security inspection, astronomy and other fields. Its core detectors are divided into direct and indirect types: the former directly converts X-rays through semiconductors or photochemical materials, but the efficiency is limited; the latter relies on scintillators to convert X-rays into visible light imaging. The current mainstream inorganic scintillators are limited by low light yield, complex preparation and environmental sensitivity, and the presence of heavy metal elements restricts biomedical applications. Therefore, promoting the development of high-performance organic scintillators has become an important research and development direction in this field. Summary of the invention

[0003] In view of the problem that the preparation of X-ray scintillators in the prior art is complicated and contains heavy metals, the present invention provides an organic scintillator with X-ray response, a liquid crystal film and its application. The preparation method of the organic scintillator of the present invention is simple and does not contain heavy metals. The organic scintillator prepared by the present invention has higher light production efficiency, realizes efficient visible conversion of X-rays, can improve the light production capacity of the detector, and has broader prospects in biomedical applications.

[0004] In a first aspect, the present invention provides an organic scintillator with X-ray response, the structural formula of which is as follows:

[0005]

[0006] Wherein, R is Br or H.

[0007] Further, when R is H, the organic scintillator is DMAC-TRZ, and its synthesis method is as follows:

[0008] In a nitrogen atmosphere, A, B, t-BuONa, Pd 2 (dba) 3 , dissolved in toluene, add (t-Bu) 3 P, heated and stirred at 110°C for 24h, then distilled under reduced pressure and dried, and then purified by silica gel column chromatography to obtain the compound, and finally recrystallized by DCM and MeOH to obtain the product DMAC-TRZ.

[0009] Furthermore, when R is Br, the organic scintillator is DMAC-TRZBr, and its synthesis method is as follows:

[0010] Under nitrogen environment, DAMC-TRZ was added to the reaction bottle, and then NBS was dissolved in THF and added to the reaction bottle. The reaction was carried out in an ice-water bath for 18 hours, and then the solvent was distilled off under reduced pressure. The compound was purified by silica gel column chromatography, and finally the product DMAC-TRZBr was obtained by recrystallization with DCM and MeOH.

[0011] In a second aspect, the present invention provides a liquid crystal film prepared from the organic scintillator, wherein the liquid crystal film is a cholesteric luminescent liquid crystal film, and the preparation method of the liquid crystal film is as follows:

[0012] Step 1: dissolve the organic scintillator, C6M, R / S5011, and BDK in dichloromethane at a mass ratio of 1:96:2:1 to prepare a mixed solution and stir for 1 hour; the structural formulas of C6M, R / S5011, and BDK are as follows:

[0013]

[0014] Step 2: Use 50 μm polystyrene (PS) microspheres as spacers, assemble glass slides to form a liquid crystal box with a thickness of 50 μm, and seal the edges with ultraviolet light curing glue.

[0015] Step 3: Subsequently, the mixed solution obtained in step 1 is evenly coated on the surface of a glass slide, and the solvent is evaporated at 120° C. for 5 minutes to obtain a clear liquid crystal prepolymer.

[0016] Step 4: Introduce the prepolymer into the edge of the liquid crystal box through a capillary tube, and use capillary force to evenly fill the box cavity; after cooling to 90°C and keeping the temperature constant for 5 minutes, irradiate with 365nm ultraviolet light for 20 seconds to complete the photocrosslinking reaction, and finally peel off the liquid crystal box to obtain a transparent and highly flexible polymer liquid crystal film.

[0017] In a third aspect, the present invention provides an application of the liquid crystal film, wherein the scintillator film is used for X-ray imaging to provide a high-resolution imaging effect. X-ray imaging method: a mini X-ray tube is used to image the film, after the ray source is turned on, the object to be measured is placed between the film and the ray tube, the film exhibits uniform green fluorescence under X-ray excitation, and a clear projection of the internal structure of the object can be directly observed on the back thereof.

[0018] Beneficial effects: 1) The organic scintillator developed by the present invention is a fully organic scintillator with a simple synthesis strategy, and has the advantages of fewer reaction steps and low cost. 2) The present invention prepares a thin film by co-polymerizing the scintillator with the liquid crystal monomer C6M, and has excellent machinability and long-term stability. 3) The present invention can achieve high-yield film preparation, and supports multi-scintillator doping regulation, significantly improving the sensitivity and resolution of X-ray imaging. The scintillator imaging system used in traditional medicine is generally 5LP / mm, while the resolution of the thin film prepared by the invention can reach 20LP / mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 These are the basic photophysical properties of the DMAC-TRZ and DMAC-TRZBr compound solutions in Example 2 of the present invention.

[0020] Figure 2 It is the radioluminescence performance of the DMAC-TRZ and DMAC-TRZBr compound powders in Example 3 of the present invention.

[0021] Figure 3 These are the photophysical properties of the R / S-DMAC-TRZ and R / S-DMAC-TRZBr films in Example 4 of the present invention.

[0022] Figure 4 This is the imaging effect of the thin film prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described in detail below through embodiments, but the protection scope of the present invention is not limited to the embodiments.

[0024] In the embodiment of the present invention, NBS, Pd 2 (dba) 3 、(t-BuO) 3 Supplier of P: Anage Chemical & 3A (Anhui Zesheng Technology Co., Ltd.); Supplier of C6M, BDK, A, and B: Bid Pharmaceutical Technology Co., Ltd.; Supplier of R / S5011: Shanghai McLean Biochemical Technology Co., Ltd.; Supplier of dichloromethane: Sinopharm Chemical Reagent Co., Ltd.; Supplier of toluene and t-BuONa: Nanjing Wanqing Co., Ltd.

[0025] Example 1: Preparation of DMAC-TRZ and DMAC-TRZBr

[0026] 1) The synthetic route of DMAC-TRZ is as follows:

[0027]

[0028] Specific preparation method of DMAC-TRZ:

[0029] Under nitrogen atmosphere, A (1.2 eq, 5.74 mmol, 2227.9 mg), B (1 eq, 4.78 mmol, 1000 mg), t-BuONa (3 eq, 1.06 mmol, 1378.1 mg), Pd 2 (dba) 3 (0.05eq, 0.24mmol, 218.9mg) was dissolved in 30ml toluene and 220mg (t-Bu) was added. 3 P, heated and stirred at 110°C for 24h, then distilled under reduced pressure and dried, and then purified by silica gel column chromatography to obtain compound DMAC-TRZ, eluent PE (petroleum ether): DCM (dichloromethane) = 10:1, and finally recrystallized from DCM and MeOH to obtain the product (4.469mmol, yield 93.4%).

[0030] The compound DMAC-TRZ (8 mg) was dissolved in 0.5 mL of a deuterated reagent, and the structure of the compound was characterized using a 400 Hz nuclear magnetic resonance spectrometer. The structure of DMAC-TRZ was determined by hydrogen nuclear magnetic resonance spectroscopy as follows:

[0031] DMAC-TRZ H NMR spectrum determination data: 1 HNMR(400MHz,Chloroform-d)δ9.03(d,J=8.5Hz,2H),8.82(dd,J=8.2,1.7Hz,4H) ,7.67–7.47(m,10H),7.02–6.92(m,4H),6.38(dd,J=7.6,1.9Hz,2H),1.73(s,6H).

[0032] 2) The synthetic route of DMAC-TRZBr is as follows:

[0033]

[0034] The specific preparation method of DMAC-TRZBr:

[0035] Under nitrogen environment, DAMC-TRZ (1eq, 2.32mmol, 1200mg) was added to the reaction bottle. Then NBS (2eq, 4.646mmol, 826.9mg) was dissolved in 40ml THF and poured into the reaction bottle. The reaction was carried out under ice-water bath for 18h, and then vacuum distillation was performed to dryness, and then silica gel column chromatography was performed to purify the compound DMAC-TRZBr, the eluent PE:DCM==5:1, and finally the product (1.864mmol, yield 80.2%) was obtained by recrystallization from DCM and MeOH.

[0036] The compound DMAC-TRZBr (8 mg) was dissolved in 0.5 mL of a deuterated reagent, and the structure of the compound was characterized using a 400 Hz nuclear magnetic resonance spectrometer. The structure of DMAC-TRZBr was determined by hydrogen nuclear magnetic resonance spectroscopy as follows:

[0037] DMAC-TRZBr H NMR spectrum determination data: 1 HNMR(400MHz,Chloroform-d)δ9.02(s,2H),8.81(dd,J=8.2,1.6Hz,4H),7.69–7.48(m,10H),7.08(dd,J=8.8,2.3Hz,2H),6.24(d,J=8.8Hz,2H),1.65(s,6H).

[0038] Example 2: Photophysical property test of compound DMAC-TRZ and DMAC-TRZBr solution

[0039] DMAC-TRZ and DMAC-TRZBr were prepared into 1×10 -5 mol / L toluene solution, the solution was tested for fluorescence spectrum using Hitachi F-4700 fluorescence spectrometer, and the obtained data was imported into origin software for normalization and mapping. Figure 1 In (a), the luminescence lifetime of the solution was tested using the Edinburgh FLS980 steady-state-transient fluorescence spectrometer, and the obtained data was imported into the origin software for normalization and mapping. Figure 1 (b) and (c) in .

[0040] like Figure 1 As shown in (a), DMAC-TRZ and DMAC-TRZBr both exhibited blue-green luminescence in toluene solution; Figure 1 As shown in (b) and (c), due to the influence of the heavy atom effect, both the instantaneous lifetime and the delayed lifetime are shortened, which proves the accelerating effect of heavy atoms on the charge transfer process within the molecule.

[0041] Example 3: X-ray radiation performance test of compound DMAC-TRZ and DMAC-TRZBr powder

[0042] The DMAC-TRZ and DMAC-TRZBr powders were fixed with a quartz clip with a groove of 0.1 mm in the middle. The Edinburgh FLS980 steady-state-transient fluorescence spectrometer was used to test the radiation spectrum of the powders. The light source used was a Mini-X-ray source. When conducting the light production test, commercially available scintillator anthracene was used as a comparison. The test data was imported into the origin software for mapping. Figure 2(b) in the figure. The sample was then continuously irradiated to test the stability of the sample under continuous X-ray irradiation. The test data was imported into the origin software for mapping. Figure 2 (c) in .

[0043] Figure 2 (a) shows the absorption capacity of two scintillator materials prepared in Example 1 and the commercially available scintillator material anthracene for X-rays. The absorption capacity of a compound for X-rays mainly depends on the density of the object and the atomic number of the atoms contained. Figure 2 As shown in (b), the light yield calculated by the DMAC-TRZ and DMAC-TRZBr tests is significantly higher than that of the commercially available scintillator anthracene, which can improve the light yield of the detector and achieve efficient X-ray energy conversion. Figure 2 As shown in (c), after long-term X-ray irradiation, the radiation intensity of the two prepared scintillator materials remains basically unchanged, indicating that the scintillator has good stability.

[0044] Example 4: Preparation of liquid crystal film based on DMAC-TRZ and DMAC-TRZBr and testing of photophysical properties

[0045] In this embodiment, R / S-DMAC-TRZ and R / S-DMAC-TRZBr films were prepared based on the compounds DMAC-TRZ and DMAC-TRZBr doped with C6M, and the photophysical properties of the prepared liquid crystal films were tested.

[0046] (1) Method for preparing R / S-DMAC-TRZ film based on compound DMAC-TRZ doped with C6M:

[0047] 50 μm polystyrene (PS) microspheres were used as spacers, and glass slides were assembled to form a liquid crystal box with a thickness of 50 μm, which was then sealed and fixed with UV curing adhesive.

[0048] DMAC-TRZ, C6M, R / S5011, and BDK were dissolved in dichloromethane (DCM) in a mass ratio of (1:96:2:1), and a mixed solution was prepared and stirred for 1h. The mixed solution was evenly coated on the surface of a glass slide, and the solvent was evaporated at 120°C for 5min to obtain a clear liquid crystal prepolymer. The prepolymer was introduced into the edge of the liquid crystal box through a capillary, and the capillary force was used to uniformly fill the box cavity. After cooling to 90°C and keeping the temperature constant for 5min, the photocrosslinking reaction was completed by irradiating with 365nm ultraviolet light for 20s, and finally the liquid crystal box was peeled off to obtain a transparent and highly flexible polymer liquid crystal film. R / S5011 has two configurations. When R / S5011 is in R-configuration, the obtained film is recorded as R-DMAC-TRZ. When R / S5011 is in S-configuration, the obtained film is recorded as S-DMAC-TRZ.

[0049] (2) Method for preparing R / S-DMAC-TRZBr film based on compound DMAC-TPZBr doped with C6M:

[0050] 50 μm polystyrene (PS) microspheres were used as spacers, and glass slides were assembled to form a liquid crystal box with a thickness of 50 μm, which was then sealed and fixed with UV curing adhesive.

[0051] DMAC-TPZBr, C6M, R / S5011, and BDK were dissolved in dichloromethane (DCM) in a mass ratio of (1:96:2:1), and a mixed solution was prepared and stirred for 1h. The mixed solution was evenly coated on the surface of a glass slide, and the solvent was evaporated at 120°C for 5min to obtain a clear liquid crystal prepolymer. The prepolymer was introduced into the edge of the liquid crystal box through a capillary, and the capillary force was used to uniformly fill the box cavity. After cooling to 90°C and keeping the temperature constant for 5min, the photocrosslinking reaction was completed by irradiating with 365nm ultraviolet light for 20s, and finally the liquid crystal box was peeled off to obtain a transparent and highly flexible polymer liquid crystal film. When R / S5011 is R-configuration, the obtained film is recorded as R-DMAC-TRZBr. When R / S5011 is S-configuration, the obtained film is recorded as S-DMAC-TRZBr.

[0052] (3) The photophysical properties of the films prepared based on DMAC-TRZ and DMAC-TPZBr were tested, and the results are as follows:

[0053] The films prepared based on DMAC-TRZ and DMAC-TPZBr both showed yellow-green color under fluorescent light, and when excited by 365nm ultraviolet light, the films both showed green emission.

[0054] The fluorescence spectrum of the film was tested using a Hitachi F-4700 fluorescence spectrometer, and the obtained data was imported into the origin software for normalized mapping. Figure 3 (a) in . Figure 3 (a) is the emission spectrum of the film under 365nm excitation. Figure 3 (a) shows the change of the normalized intensity of the film R-DMAC-TRZ and R-DMAC-TRZBr under fluorescence (FL) as a function of wavelength. The Edinburgh FLS980 steady-state-transient fluorescence spectrometer was used to replace the light source with a Mini-X-ray tube to test the radiation spectrum of the film. The obtained data was imported into the origin software for normalized mapping. Figure 3 (b) in . Figure 3 (b) is the radiant luminescence spectrum of the film under X-ray excitation. Figure 3(b) shows the variation of the normalized intensity of the films R-DMAC-TRZ and R-DMAC-TRZBr under X-ray excitation (RL) with wavelength. Figure 3 The spectra in (a) and (b) show that there is no significant difference in the emission peak positions of the films under photoluminescence and radioluminescence conditions, and both exhibit green emission characteristics around 500nm.

[0055] The above two films were tested using a JASCO CPL-300 spectrometer to test their circularly polarized luminescence spectra and luminescence asymmetry factors. The obtained data were imported into the Origin software for mapping. Figure 3 (c) and (d) in . Figure 3 (c) shows the circularly polarized luminescence characteristics of the four films R-DMAC-TRZ, S-DMAC-TRZ, R-DMAC-TRZBr, and S-DMAC-TRZBr in the 400-700nm band. Their circularly polarized spectra show a mirror-symmetric relationship and reach a peak at 500nm. Figure 3 (d) is the asymmetric luminescence factor curve of the film, and the vertical axis is the circularly polarized luminescence asymmetry factor (g lum The horizontal axis is the wavelength. The g of the film at 500nm lum The value reaches 1.06, indicating that the material has significant circularly polarized luminescence characteristics.

[0056] Example 5: Application of X-ray imaging of the liquid crystal film prepared in Example 4

[0057] This example tests the X-ray imaging application of two films, R-DMAC-TRZ and R-DMAC-TRZBr.

[0058] Figure 4 (a) shows the direct X-ray imaging method: after turning on the radiation source, the object to be measured is placed between the film and the radiation tube. The film exhibits uniform green fluorescence under X-ray excitation, and a clear projection of the object's internal structure can be directly observed on its back.

[0059] Figure 4 (b) shows the resolution of the film under the standard line pair card. This parameter reflects the imaging clarity. The resolution of both films reaches 20LP / mm. In addition, Figure 4 (b) shows the imaging effect of the chip and the fish. This imaging method can clearly present the internal structure of the chip and the skeletal framework of the fish.

[0060] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to the form and details without departing from the spirit and scope of the present invention.

Claims

1. An organic scintillator having an X-ray response, characterized in that: Its structural formula is as follows: Wherein, R is Br or H.

2. The organic scintillator according to claim 1, characterized in that: When R is H, the organic scintillator is DMAC-TRZ, and its synthesis method is as follows: Under nitrogen environment, A, B, t-BuONa, Pd2(dba)3 were dissolved in toluene, (t-Bu)3P was added, heated and stirred at 110°C for 24h, then distilled under reduced pressure and dried, and then purified by silica gel column chromatography to obtain the compound, and finally recrystallized by DCM and MeOH to obtain the product DMAC-TRZ; the synthetic route is as follows:

3. The organic scintillator according to claim 2, characterized in that: When R is Br, the organic scintillator is DMAC-TRZBr, and its synthesis method is as follows: Under nitrogen environment, DAMC-TRZ was added to the reaction bottle, NBS was dissolved in THF and then added to the reaction bottle, and the reaction was carried out in an ice-water bath for 18 hours, and then the solvent was distilled off under reduced pressure, and then the compound was purified by silica gel column chromatography, and finally the product DMAC-TRZBr was obtained by recrystallization with DCM and MeOH; the synthesis route is as follows:

4. A liquid crystal film prepared based on the organic scintillator according to any one of claims 1 to 3, characterized in that: The preparation method of the liquid crystal film is as follows: Step 1: dissolve the organic scintillator, C6M, R / S5011, and BDK in dichloromethane at a mass ratio of 1:96:2:1 to prepare a mixed solution and stir for 1 hour; the structural formulas of C6M, R / S5011, and BDK are as follows: Step 2: Using polystyrene microspheres as spacers, assembling glass slides to form a liquid crystal cell, and sealing and fixing the edges with UV curing glue; Step 3: Subsequently, the mixed solution obtained in step 1 is evenly coated on the surface of a glass slide, and the solvent is evaporated at 120° C. for 5 minutes to obtain a clear liquid crystal prepolymer; Step 4: Introduce the prepolymer into the edge of the liquid crystal box through a capillary tube, and use capillary force to evenly fill the box cavity; after cooling to 90°C and keeping the temperature constant for 5 minutes, irradiate with 365nm ultraviolet light for 20 seconds to complete the photocrosslinking reaction, and finally peel off the liquid crystal box to obtain a transparent and flexible polymer liquid crystal film.

5. The use of the liquid crystal film according to claim 4, characterized in that: The liquid crystal film is used for X-ray imaging.

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