Uracil-based fingerprint detection fluorescent material as well as preparation method and application thereof

Abstract

The invention discloses a fingerprint detection fluorescent material based on uracil as well as a preparation method and application of the fingerprint detection fluorescent material based on uracil, and belongs to the technical field of latent fingerprint detection. The preparation method comprises the following steps: dissolving the fingerprint detection fluorescent material based on uracil in dichloromethane, adding montmorillonite powder according to a mass ratio of 1: 30, uniformly stirring and mixing, carrying out rotary evaporation to remove a solvent, and drying the obtained solid in a vacuum oven at 60 DEG C to obtain the aryl vinyl uracil derivative-montmorillonite composite material. The developing powder is used for fingerprint extraction. The method is simple to operate, low in toxicity, high in development efficiency and clear in development.

Description

Technical Field

[0001] The present invention belongs to the technical field of latent fingerprint detection, and particularly relates to the preparation of a fluorescent composite material based on vinyluracil derivatives - montmorillonite and its application in latent fingerprint detection. Background Art

[0002] Fingerprints, also known as handprints, are the patterns formed by the uneven skin on the fingertips of the human fingers. Fingerprints have characteristics such as uniqueness, persistence, universality, easy extraction, and resistance to storage. Therefore, fingerprints are one of the most important physical evidences that can directly identify a person at the crime scene, known as the "prime physical evidence", providing important clues and evidence for criminal investigation, forensic identification, and court litigation.

[0003] According to the different ways of fingerprints left at the scene, fingerprints can be divided into three categories: visible fingerprints, plastic fingerprints, and latent fingerprints. Among them, visible fingerprints and plastic fingerprints are convenient for observation and extraction, but latent fingerprints (LFPs) are often difficult to be detected, which are the most common fingerprints at the crime scene. Therefore, by applying fingerprint trace inspection technology, the efficiency of criminal investigation can be significantly improved, and the speed of handling criminal cases can be increased; on the other hand, with the help of criminal trace inspection technology, the quality of criminal litigation evidence can be effectively improved, the problem of supplementary acceptance of criminal cases can be avoided, and the rights and interests of victims of criminal cases can be protected.

[0004] Current LFP detections can be classified into optical development methods (such as ultraviolet light and laser inspection), physical adsorption methods (such as powder brushing method and iodine fuming method), and chemical development methods according to their detection principles [Wang, Z.; Jiang, X.; Liu, W.; Lu, G.; Huang, X. Sci. China: Chem. 2019, 62, 889.]. Optical development methods such as ultraviolet light inspection and laser inspection methods have poor contrast, and ultraviolet light and laser cause great harm to the human body. Chemical development methods utilize specific chemical reactions between developers and components in latent fingerprints, such as organic substances like lipids and amino acids, to develop fingerprints. Traditional chemical development methods include ninhydrin spraying method, silver nitrate method, cyanoacrylate (502 glue) fuming method, 1,8-diazabicyclo[5.4.0]undec-7-ene (DFO) method, dimethylaminocinnamaldehyde (DMAC) method, and so on. Although compared with physical development methods, it has advantages such as higher sensitivity and clarity, etc., the ninhydrin method is greatly affected by the environment, the silver nitrate method has poor development effect on latent fingerprints on objects such as paper, and the cyanoacrylate fuming method has great toxicity and has a greater impact on the human body. Although these traditional latent fingerprint development methods meet the requirements of fingerprint detection to a certain extent, they still cannot meet the actual requirements for the sensitivity, clarity, and safety of fingerprint detection. In addition, fingerprints at the crime scene are usually relatively complex, such as containing substances like blood, explosives, drug metabolites, and drugs, and existing detection methods still cannot meet the requirements for the development of such special fingerprints.

[0005] In recent years, with the development of nanotechnology, scientists have found that due to the special size (1 - 100 nm) of nanoscale fluorescent materials, they possess unique physical, chemical, and electronic properties. Fluorescent nanomaterials usually exhibit characteristics such as high sensitivity, high resolution, fast response speed, and non-destructive visualization, and thus are also widely used in the detection field. Organic fluorescent nanomaterials have attracted much attention due to their diverse structures, easy preparation and modification, and easily tunable luminescence properties [Jin, X.; Bi, T.; Xin, R.; Wu, G.; Xu, T.; Ma, R. Chin. J. Org. Chem. 2020, 40, 4184 - 4202]. Currently, there are some problems to be solved for the organic fluorescent materials used in fingerprint detection, such as aggregation-induced fluorescence quenching, the need for a large amount of organic solvents as dispersants, and weak interaction with latent fingerprints. Currently, most organic fluorescent molecules are organic π-conjugated molecules. When such molecules aggregate, fluorescence quenching occurs due to the intermolecular π-π interaction. Therefore, such molecules are only suitable for emitting fluorescence in solution and dispersion systems. At the same time, such molecules usually contain aromatic groups and conjugated groups and lack water-soluble groups, so they can only be dissolved in organic solvents and have low solubility in water. In addition, fingerprint traces usually contain sweat, inorganic salts, oils, amino acids, cholesterol, and proteins, etc. Organic conjugated small molecules usually do not contain groups that can have strong interactions with fingerprint components. Therefore, developing an effective means of organic fluorescent fingerprint detection reagents that can have stronger interactions with fingerprints, low toxicity, convenient use, and a wide range of applications has important application value for discovering fingerprint detection materials with high sensitivity, fast speed, high visualization quality, low toxicity, and convenient use. Summary of the Invention

[0006] The object of the present invention is to design and prepare a novel class of organic light-emitting small molecules based on the structural characteristics of organic light-emitting materials and the physical and chemical properties of different functional groups, and to prepare a fluorescent composite material for detecting latent fingerprints by dispersing fluorescent molecules in montmorillonite powder. As a structural unit of nucleic acid, pyrimidine has the characteristics of low toxicity, easy formation of hydrogen bonds, and solubility in water. For the first time, the present invention uses pyrimidine as a structural unit to connect conjugated heterocycles (substituted benzene rings) to prepare organic fluorescent molecules, and regulates the solubility of the molecules in low-toxic solvents such as alcohols and water by using the hydrogen-bonding unit of pyrimidine and the modification of alkyl chains. At the same time, intermolecular forces such as hydrogen bonds and van der Waals forces are used to increase the interaction between fluorescent molecules and fingerprints.

[0007] The specific technical solution of the present invention is as follows:

[0008] A fingerprint detection fluorescent material based on uracil, characterized in that it uses pyrimidinyl ethylene as the parent body and has the following chemical structural formula:

[0009]

[0010] Among them, R on the 1-position nitrogen atom of pyrimidine 1 can be an alkyl chain with 4 to 16 carbon atoms, and the aryl group Ar substituted on ethylene can be phenyl, substituted phenyl or heteroaromatic ring.

[0011] Furthermore, the substituted phenyl is 4-methylphenyl, 4-methoxyphenyl, 4-cyanophenyl, 4-tert-butylphenyl, 3-methylphenyl, 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-dimethylaminophenyl or 4-hydroxyphenyl; the heteroaromatic ring is 2-furyl, 2-thienyl, 2-pyrrolyl, 2-imidazolyl, 2-oxazolyl, 2-thiazolyl, 2-benzofuranyl, 2-benzothienyl, 2-benzimidazolyl, 2-indolyl, 2-benzoxazolyl, 2-benzothiazolyl or 2-benzimidazolyl.

[0012] A preparation method of a fluorescence material for fingerprint detection based on uracil comprises the following steps:

[0013] Step 1: Synthesize 5-formyluracil. For details, refer to the literature [Mattelaer H P, Van Hool A S, de Jong F, et al. New Metal-Free Route towards Imidazole-Substituted Uridine[J]. European journal of organic chemistry, 2020, 2020(26):4022-4025.]

[0014] Step 2: Preparation of compound A

[0015] Add 5-formyluracil, 1-bromoalkane with 4 to 16 carbon atoms, tetrabutylammonium chloride, and triethylamine into a reactor. The addition ratio of the four compounds is: 1:0.85 - 1:0.14:2; use dimethyl sulfoxide as the reaction solvent, heat to 65 °C and stir for 3 - 5 h, then pour the reaction solution into ice water and extract with dichloromethane. After combining the organic phases, dry with anhydrous sodium sulfate, rotary evaporate to remove the organic solvent to obtain the crude product of compound A, and then recrystallize with ethanol, filter, and dry to obtain compound A;

[0016] Step 3: Preparation of compound B

[0017] Under nitrogen protection at room temperature, aryltriphenylphosphonium bromide, potassium tert-butoxide and dry toluene were added to a reactor. After the solution turned dark red or orange, compound A was added. The molar ratio of aryltriphenylphosphonium bromide, potassium tert-butoxide to compound A was 1.3 - 1.5: 1.5 - 2: 1. The reaction mixture was stirred at room temperature for 1 - 1.5 h. After the reaction, a precipitate was formed. The precipitate was removed by filtration, and the solvent in the filtrate was removed by rotary evaporation to obtain the crude product of compound B. The fluorescent dye compound B, namely the uracil-based fingerprint detection fluorescent material, was obtained by silica gel column chromatography.

[0018] An application of a uracil-based fingerprint detection fluorescent material in fingerprint detection, and the specific steps are as follows:

[0019] Step 1: Preparation of uracil-montmorillonite fingerprint detection material

[0020] The uracil-based fingerprint detection fluorescent material, namely compound B, was dissolved in dichloromethane at a concentration of 1 mg / mL. Montmorillonite powder was added to this solution according to the mass ratio of compound B to montmorillonite of 1:30. After stirring and mixing evenly, the solvent was removed by rotary evaporation. The obtained solid was dried in a vacuum oven at 60 °C to obtain an arylvinyluracil derivative-montmorillonite composite material.

[0021] Step 2: Powder method latent fingerprint development

[0022] The ground arylvinyluracil derivative-montmorillonite composite material was taken as the developing powder and evenly sprinkled on the latent fingerprint sample. The excess powder was gently blown off with an ear bulb to make the developing powder evenly adhere to the fingerprint sample.

[0023] In the experiment, the latent fingerprint samples can be obtained by the following method: After cleaning the hands with soap, the fingers are swiped across the nose or forehead, and the fingerprint filled with the oil-sweat mixture is pressed on the surfaces of objects such as glass, stainless steel, aluminum foil, wood board, ceramic, acrylic, coin, etc. to obtain the latent fingerprint samples.

[0024] Step 3: Extracting fingerprint images

[0025] Using a 365 nm, 20 W ultraviolet lamp as the light source, irradiating on the developed fingerprint, taking pictures and recording, fixing and extracting the fingerprint. The visible fingerprint emits blue-green light or blue light, thus achieving the purpose of fluorescent latent fingerprint development.

[0026] The present invention has the following advantages:

[0027] (1) The developing method disclosed by the present invention is simple in operation, low in toxicity, high in developing efficiency and clear in development.

[0028] (2) The aryl vinyluracil derivative-montmorillonite composite material provided by the present invention is directly applied to various substrate materials in the form of particles, which can overcome the background interference of the substrate materials.

[0029] (3) The fluorescent dye molecule is a uracil derivative, which has relatively good biocompatibility and contains lipophilic groups. The aryl vinyluracil derivative-montmorillonite composite material has an affinity for the residues in latent fingerprints and can reproduce the details and various characteristic information of latent fingerprints.

[0030] (4) The present invention uses montmorillonite (MMT) as a dopant to uniformly disperse aryl vinyluracil with good fluorescence emission properties in the layered structure of the MMT clay matrix, effectively preventing the fluorescence quenching effect and enhancing the interaction force between fingerprints and fluorescent molecules by using the good hydrogen bonding ability of montmorillonite. The preparation of the aryl vinyluracil derivative-montmorillonite composite material realizes solid-state fluorescence and demonstrates the practical application value in the direction of latent fingerprint development. Description of the Drawings

[0031] Figure 1 It is the fluorescence spectrum and ultraviolet absorption spectrum of the aryl vinyluracil derivative prepared in Example 1 of the present invention.

[0032] Figure 2 It is the powder comparison effect of the aryl vinyluracil derivative-montmorillonite composite material prepared in Example 1 of the present invention under natural light (a) and ultraviolet light (b).

[0033] Figure 3 It is the fluorescence imaging effect of the aryl vinyluracil derivative-montmorillonite composite material developing powder prepared in Example 1 of the present invention on different objects.

[0034] Figure 4 It is the ultraviolet absorption spectrum of the aryl vinyluracil derivative prepared in Example 2 of the present invention.

[0035] Figure 5 It is the powder comparison effect of the aryl vinyluracil derivative-montmorillonite composite material prepared in Example 2 of the present invention under natural light (a) and ultraviolet light (b).

[0036] Figure 6 It is the fluorescence imaging effect of the aryl vinyluracil derivative-montmorillonite composite material developing powder prepared in Example 2 of the present invention on different objects.

[0037] Figure 7 It is the development effect of the aryl vinyluracil derivative-montmorillonite composite material developing powder under ultraviolet 365nm irradiation on glass under a microscope prepared in Example 2 of the present invention. Detailed Embodiments

[0038] The present invention will be described in detail below with reference to the accompanying drawings and specific examples. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manner and specific operation process are given. However, the protection scope of the present invention is not limited to the following examples.

[0039] Example 1 Preparation method and application of fluorescent dye E-2-FU:

[0040] (1) Preparation of compound A:

[0041]

[0042] 5-Formyluracil (2.80 g, 20.0 mmol), 1-bromododecane (4.237 g, 17.0 mmol), tetrabutylammonium chloride (TBAC, 0.78 g, 2.8 mmol), triethylamine (TEA, 4.05 g, 40.0 mmol) and 15 mL of dimethyl sulfoxide (DMSO) were added to a 100 mL round-bottom flask, and the mixture was stirred in an oil bath at 65 °C for 4 h. After the reaction was completed, the reaction solution was cooled to room temperature, 150 mL of water was added thereto, and the mixture was extracted three times with 50 mL of dichloromethane. The combined organic phases were washed with water, dried, and the organic solvent was removed by rotary evaporation to obtain a yellow oil. The oil was recrystallized with absolute ethanol, and the filtered solid was washed with cold absolute ethanol and dried to obtain 1.96 g of a shiny white powder (see the ultraviolet absorption spectrum and fluorescence spectrum in Figure 1 ), and the yield was 59%. 1 H NMR (400 MHz, DMSO-d6) δ 11.73 (s, 1H), 9.76 (s, 1H), 8.49 (s, 1H), 3.79 (t, J = 7.3 Hz, 2H), 1.59 (q, J = 7.0 Hz, 2H), 1.23 (s, 18H), 0.85 (t, J = 6.6 Hz, 3H).

[0043] (2) Preparation of fluorescent dye E-2-FU:

[0044]

[0045] Under nitrogen protection, (2-furylmethyl)triphenylphosphonium bromide (2.75 g, 6.5 mmol), 20 mL of dry toluene and potassium tert-butoxide (0.84 g, 7.5 mmol) were added to a dry 100 mL two-necked flask, and the mixture was reacted at room temperature for 1 h. The white suspension turned into a dark red solution. Compound A (1.54 g, 5.0 mmol) was added, and the mixture was continuously stirred at room temperature for 2 h, and a white precipitate was formed. The precipitate was filtered off. The filtrate was concentrated under reduced pressure to remove the solvent to obtain a crude product, and the crude product was separated by column chromatography (silica gel, V PE :V EA(ratio = 4:1), 1.10 g of furan vinyluracil was obtained with a yield of 60%.

[0046] The basic data of dye E-2-FU are as follows:

[0047] Pale yellow powdery solid

[0048] 1 H NMR (400 MHz, CDCl3) δ 8.84 (s, 1H), 7.85 (s, 1H), 7.33 (s, 1H), 6.44 (s, 1H), 6.38 (s, 1H), 6.31 (d, J = 12.7 Hz, 1H), 6.19 (d, J = 12.8 Hz, 1H), 3.77 (t, J = 7.4 Hz, 2H), 1.73 (q, J = 7.4 Hz, 3H), 1.26 (d, J = 7.3 Hz, 18H), 0.88 (t, J = 6.7 Hz, 3H). 13 CNMR (101 MHz, CDCl3) δ 152.19, 142.78, 141.64, 117.16, 116.48, 112.14, 111.82, 110.71, 49.05, 31.91, 29.61, 29.60, 29.55, 29.46, 29.33, 29.28, 29.20, 26.43, 22.69, 14.12. HRMS (m / z) [M + H] + calcd for C 22 H 33 N2O3 373.2486, found: 373.2491.

[0049] The preparation method of the E-2-FU-montmorillonite composite fingerprint developing powder is as follows:

[0050] Add 20 mg of E-2-FU and 10 mL of dichloromethane to a 20 mL round-bottom flask to dissolve all of the E-2-FU. Add 600 mg of montmorillonite powder, ultrasonicate the mixture for 3 - 5 min to mix it evenly, and rotary evaporate to remove the solvent. The obtained powder is dried in a vacuum oven at 60 °C for 5 - 8 h to obtain a dry pale yellow developing powder ( Figure 2 ). Using the powder developing method, take a small amount of the E-2-FU-montmorillonite composite fingerprint developing powder ground in a mortar with a spatula, evenly sprinkle it on the surface of the object with latent fingerprints, gently blow off the excess powder with an ear bulb to make the fingerprint trace appear completely clear. Use a 365 nm, 20 W ultraviolet lamp as the excitation light source to see a fingerprint image emitting blue-green fluorescence, and fix the fingerprint details with a mobile phone or a microscope ( Figure 3 ).

[0051] Example 2 Preparation method and application of fluorescent dye E-phU:

[0052] (1) Preparation of Fluorescent Dye E-phU

[0053]

[0054] Under nitrogen protection, triphenylbenzylphosphonium bromide (1.00 g, 2.3 mmol), 10 mL of dry toluene and potassium tert-butoxide (0.33 g, 3.0 mmol) were added to a dry 100 mL two-necked round-bottom flask. The mixture was stirred at room temperature for 1 h, and the white suspension turned into a dark red liquid. Compound A (0.46 g, 1.5 mmol) was added, and stirring was continued at room temperature for 2 h to form a white precipitate, which was filtered off. The solvent in the filtrate was removed by rotary evaporation to obtain a crude product, and the crude product was purified by column chromatography (silica gel, dichloromethane:ethyl acetate = 40:1) to obtain 0.3 g of white styryluracil with a yield of 51%.

[0055] The structural characterization data of the fluorescent dye E-phU are as follows:

[0056] White powdery solid

[0057] 1 H NMR (400 MHz, DMSO-d6) δ 11.44 (s, 1H), 8.02 (s, 1H), 7.48–7.40 (m, 3H), 7.35 (t, J = 7.7 Hz, 2H), 7.26–7.21 (m, 1H), 6.88 (d, J = 16.4 Hz, 1H), 3.71 (t, J = 7.2 Hz, 2H), 1.67–1.55 (m, 2H), 1.23 (s, 19H), 0.88–0.81 (m, 3H). 13 C NMR (101 MHz, CDCl3) δ 162.27, 149.83, 140.70, 137.27, 129.96, 128.67, 127.76, 126.43, 119.35, 112.41, 49.13, 31.91, 29.62, 29.55, 29.47, 29.35, 29.20, 26.47, 22.69, 14.13. HRMS (m / z) [M+H] + calcd for C 24 H 35 N2O2 383.2693, found: 383.2687.

[0058] (3) Preparation method of E-phU-montmorillonite composite fingerprint developing powder, and the specific operation is as follows:

[0059] Add 20 mg of E-phU and an appropriate amount of dichloromethane to a 20 mL round-bottom flask to completely dissolve E-phU. Add 600 mg of montmorillonite powder. Ultrasonic the flask containing the mixture for 3 - 5 min to make it homogeneous, and then rotary evaporate to remove the solvent. The dried powder is dried in a vacuum oven at 60 °C for 5 - 8 h to obtain a dry pale yellow developer powder( Figure 5 ). Using the powder development method, take a small amount of the ground E-phU-montmorillonite composite developer powder with a spatula and evenly sprinkle it on the latent fingerprints left on the object. Gently blow off the excess powder with an ear bulb to make the fingerprint traces appear completely and clearly. Using a 365 nm, 20 W ultraviolet lamp as the light source, a fingerprint image with visible blue fluorescence can be seen, and fix the fingerprint details with a mobile phone or microscope.

[0060] Figure 4 are the fluorescence spectrum and ultraviolet absorption spectrum of the E-phU-montmorillonite composite. Figure 5 are the powder contrast effects of the E-phU-montmorillonite composite under natural light (a) and ultraviolet light (b). Figure 6 are the fluorescence imaging effects of the E-phU-montmorillonite composite developer powder on different substrates. Figure 7 is the development effect of the E-phU-montmorillonite composite under ultraviolet irradiation at 365 nm on glass under a microscope. The above experimental results show that the E-phU-montmorillonite composite can not only show clear images of latent fingerprints on the surfaces of different substances, but also clearly show the secondary and tertiary features of fingerprints.

[0061] Example 3 Preparation of fluorescent dye E-2-TU:

[0062]

[0063] Under nitrogen protection, add (2-thienylmethyl)triphenylphosphonium bromide (2.86 g, 6.5 mmol), 20 mL of dry toluene and potassium tert-butoxide (0.84 g, 7.5 mmol) to a 100 mL dry two-necked round-bottom flask, and react at room temperature for 1 h. The white suspension turns into a dark red liquid. After reacting for 1 h, add compound A (1.54 g, 5.0 mmol), and continue to react at room temperature for 2 h to obtain a crude product, which is purified by column chromatography (silica gel, V PE :V EA = 4:1) to obtain 1.11 g of thienylvinyluracil with a yield of 58%. The present invention selects the E-configuration product E-2-TU as the fluorescent material.

[0064] The basic data of the fluorescent dye E-2-TU are as follows:

[0065] Yellow solid powder

[0066] 11H NMR (400 MHz, CDCl3) δ 8.79 (s, 1H), 7.72 (d, J = 15.9 Hz, 1H), 7.22 (s, 1H), 7.17 (d, J = 5.1 Hz, 1H), 7.04 (d, J = 3.6 Hz, 1H), 6.98 (t, J = 4.4 Hz, 1H), 6.54 (d, J = 15.9 Hz, 1H), 3.76 (t, J = 7.5 Hz, 2H), 1.72 (p, J = 7.0 Hz, 2H), 1.30 (d, 21H), 0.88 (t, J = 6.7 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 162.01, 149.66, 143.00, 140.94, 127.68, 126.42, 124.38, 123.82, 119.11, 112.00, 49.10, 31.90, 29.60, 29.53, 29.44, 29.33, 29.19, 29.17, 26.45, 22.68, 14.11. HRMS (m / z) [[M+H]] + calcd for C 22 H 33 N2O2S 389.2257, found: 389.2258.

[0067] Example 4 Preparation of Fluorescent Dye E-o-MephU:

[0068]

[0069] Add (3-methylbenzyl)triphenylphosphonium bromide (3.57 g, 8.0 mmol), 20 mL of dry toluene and potassium tert-butoxide (1.67 g, 10.4 mmol) to a dry 100 mL two-necked flask under nitrogen protection. React at room temperature for 1 h, changing from a white suspension to a dark red liquid. After reacting for 1 h, add Compound A (1.84 g, 6.0 mmol), and continue to react at room temperature for 2 h to obtain a crude product. Purify by column chromatography (silica gel, V DCM :V EA = 10:1) to obtain 1.42 g of white o-tolylvinyluracil with a yield of 66%. The E-configured product E-o-MephU of the present invention is selected as the fluorescent probe material.

[0070] The basic structure characterization data of the fluorescent dye E-o-Meph are as follows:

[0071] White solid powder

[0072] 11H NMR (400 MHz, DMSO-d6) δ 11.43 (s, 1H), 8.04 (s, 1H), 7.64 (d, J = 16.3 Hz, 1H), 7.51 (d, J = 7.4 Hz, 1H), 7.22–7.10 (m, 3H), 6.75 (d, J = 16.3 Hz, 1H), 3.70 (t, J = 7.3 Hz, 2H), 2.33 (s, 3H), 1.62 (s, 2H), 1.23 (s, 19H), 0.84 (t, J = 6.5 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 162.44, 150.03, 140.94, 136.46, 135.97, 130.40, 128.09, 127.64, 126.14, 124.98, 120.67, 112.72, 49.11, 31.92, 29.63, 29.56, 29.49, 29.36, 29.22, 26.48, 22.70, 19.95, 14.15. FT-IR (KBr, cm -1 −1): 3157.9, 3046.0, 3029.6, 2952.5, 2921.6, 2852.2, 1672.0, 1462.7, 1427.1, 1375.0, 1352.8, 974.8, 744.4. HRMS (m / z) [M + H] + calcd for C 24 H 35 N2O2 397.2850, found: 397.2847。

Claims

1. A fingerprint detection fluorescent material based on uracil, characterized in that: Taking pyrimidinylethylene as the parent, it has the following chemical structure: Among them, R 1 It is an alkyl chain with a length of 4 to 16 carbon atoms, and the aromatic group Ar substituted on the ethylene is a phenyl group, a substituted phenyl group or an aromatic heterocycle.

2. The fingerprint detection fluorescent material based on uracil according to claim 1, characterized in that: The substituted phenyl group is 4-methylphenyl, 4-methoxyphenyl, 4-cyanophenyl, 4-tert-butylphenyl, 3-methylphenyl, 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-dimethylaminophenyl or 4-hydroxyphenyl; the aromatic heterocycle is 2-furyl, 2-thienyl, 2-pyrrolyl, 2-imidazolyl, 2-oxazolyl, 2-thiazolyl, 2-benzofuranyl, 2-benzothienyl, 2-benzimidazolyl, 2-indolyl, 2-benzoxazolyl, 2-benzothiazolyl or 2-benzimidazolyl.

3. A method for preparing the uracil-based fingerprint detection fluorescent material according to claim 1, comprising the following steps: Step 1: Synthesis of 5-formyluracil; Step 2: Preparation of Compound A Add 5-formyluracil, 1-bromoalkane with a carbon number of 4-16, tetrabutylammonium chloride and triethylamine to the reactor, and the addition ratio of the four compounds is 1:0.85-1:0.14:2; use dimethyl sulfoxide as the reaction solvent, heat to 65°C and stir for 3-5 hours, pour the reaction solution into ice water and extract with dichloromethane, combine the organic phases and dry with anhydrous sodium sulfate, remove the organic solvent by rotary evaporation to obtain a crude product of compound A, then recrystallize with ethanol, filter, and dry to obtain compound A; Step 3: Preparation of compound B Under nitrogen protection at room temperature, aryl triphenylphosphine bromide, potassium tert-butoxide and dry toluene are added to a reactor. When the solution turns dark red or orange, compound A is added, and the molar ratio of aryl triphenylphosphine bromide, potassium tert-butoxide and compound A is 1.3-1.5:1.5-2:

1. The reaction mixture is stirred at room temperature for 1-1.5 hours. After the reaction is completed, a precipitate is generated, the precipitate is removed by filtration, and the solvent in the filtrate is removed by rotary evaporation to obtain a crude product of compound B. The fluorescent dye compound B is separated by a silica gel column, that is, the fingerprint detection fluorescent material based on uracil.

4. An application of the uracil-based fingerprint detection fluorescent material according to claim 1 in fingerprint detection, the specific steps of which are: Step 1: Preparation of uracil-montmorillonite fingerprint detection material The uracil-based fingerprint detection fluorescent material, i.e., compound B, was dissolved in dichloromethane at a concentration of 1 mg / mL, and montmorillonite powder was added to the solution at a mass ratio of compound B to montmorillonite of 1:

30. After stirring and mixing evenly, the solvent was removed by rotary evaporation, and the obtained solid was dried in a vacuum oven at 60° C. to obtain an aromatic vinyl uracil derivative-montmorillonite composite material; Step 2: Powder method latent fingerprint development Take the ground aromatic vinyl uracil derivative-montmorillonite composite material as the developing powder, sprinkle it evenly on the latent fingerprint sample, and gently blow away the excess powder with an ear-cleaning bulb to make the developing powder evenly adhere to the fingerprint sample; Step 3: Extract fingerprint image Use 365nm, 20W ultraviolet lamp as light source, irradiate on the revealed fingerprint, take pictures and record, fix and extract the fingerprint, and it can be seen that the fingerprint glows blue-green or blue, thus achieving the purpose of fluorescent latent fingerprint development.

Images