Water-soluble AIE functional molecule and application thereof in latent fingerprint imaging

Abstract

The invention belongs to the field of latent fingerprint imaging, and particularly relates to a preparation method of a water-soluble AIE functional molecule and application of the water-soluble AIE functional molecule in latent fingerprint imaging. The water-soluble AIE molecule has the following structural general formula: # imgabs0 #, wherein R1 is triphenylamine, N-phenyl carbazole, N-phenyl phenothiazine, N-phenyl phenoxazine, 10H-phenoselenazine, or 10-phenyl-10H-phenoselenazine, R2 is phenyl phenothiazine, and R3 is phenyl phenothiazine; and Arl is an onium salt containing pyridine, quinoline or isoquinoline. The developing agent is simple in preparation method, high in aggregation state luminous efficiency, high in latent fingerprint imaging speed, high in detection sensitivity and high in imaging resolution, and has an excellent latent fingerprint imaging effect on a strong self-luminous matrix, a dark-color matrix, a rough-surface matrix, a semi-adsorptive matrix and an adsorptive matrix.

Description

Technical Field

[0001] The invention belongs to the field of latent fingerprint imaging, and more specifically relates to a preparation method of a water-soluble AIE functional molecule and its application in latent fingerprint imaging. Background Art

[0002] Fingerprints usually show unique and exclusive characteristics. Latent fingerprints are impressions with fingerprint characteristics that are formed by sweat pore secretions and adhere to the surface of the matrix. They are used to confirm the identity of criminal suspects in forensic investigations and play an important role in case investigation and prosecution. Fingerprint details are usually defined into three levels. Among them, level 1 details are macroscopic features of fingerprint veins, including arches, spirals, triangular lines, center points, etc. Level 2 details belong to the macroscopic features of fingerprint ridges and fingerprint grooves, including bifurcations, islands, end points, ridge points, rifts and folds. Level 3 details include ridge width, ridge edge morphology, ridge angle, pores, pore spacing, etc., which are microscopic details of fingerprint ridges and fingerprint grooves. Level 1 details are usually not unique enough to identify individual characteristics, while level 2 details and level 3 details can fully reflect the differences in individual characteristics. In forensic identification, level 3 details are considered the gold standard for identity identification (J.Am.Chem.Soc.2020, 142, 7497; J.Am.Chem.Soc.2024, 146, 2072).

[0003] Traditional latent fingerprint imaging methods include physical imaging methods such as powder brushing, immersion, fumigation, and spraying, as well as chemical imaging methods. Among them, the powder brushing method is the most direct and easy to implement, and is therefore widely used. However, traditional physical imaging methods represented by the powder brushing method have many disadvantages, such as poor selectivity and low imaging contrast. In order to remove excess developer, the post-dust removal process of the powder brushing method is prone to damage fingerprint details, and the unavoidable dust also poses a threat to the health of the tester. Chemical imaging methods based on iodine, ninhydrin or silver nitrate and fumigation methods have slow imaging speeds and pose potential hazards to the skin, mucous membranes, and even DNA (Adv. Mater. 2023, 35 (20), 2211917; Adv Mater 2022, 34 (35), 2202540).

[0004] In recent years, the immersion method and the spray method have gradually replaced the powder brushing method in the field of latent fingerprint imaging. Researchers have developed many new organic light-emitting materials with excellent performance for latent fingerprint development, including aggregation-induced emission (AIE) materials. Because the immersion method and the spray method can better protect the fingerprint details and prevent the operator from inhaling the powder. AIE functional molecules usually have good solid-state luminescence properties, and their inherent lipophilicity helps to adhere to latent fingerprints and improve imaging resolution. Lipophilic functional molecules require organic solvents to help dissolve, and organic solvents will dissolve and destroy the details of latent fingerprints to a certain extent, and even cause the latent fingerprints to disintegrate. Therefore, the development of simple water-soluble AIE functional molecules as latent fingerprint developers is of great significance and practical value.

[0005] Patent CN112852409A discloses a latent fingerprint developer based on AIE functional molecules and its preparation method and application. A latent fingerprint developer is obtained by dispersing AIE functional molecules in water using surfactants, and latent fingerprint imaging is performed by soaking a matrix with latent fingerprints and using hydrophobic-hydrophobic interaction and electrostatic adsorption principles. The latent fingerprint developer has a simple preparation process, low biological toxicity, fast imaging speed, and good application effect. Patent CN116003380A discloses a latent fingerprint developer, which introduces an electron donor to the para position of the quaternized pyridine nitrogen atom, designs and synthesizes a series of latent fingerprint developers, introduces hydrophobic ends and hydrophilic ends to make the molecule amphiphilic, and adsorbs to sebum secretions through hydrophobic action to achieve latent fingerprint imaging. The latent fingerprint developer is simple to synthesize, and water is used as a carrier to prepare a developer to realize the visualization of fingerprint details. Patent CN113582931A discloses a preparation method of a fluorescent probe based on the skeleton structure of the green fluorescent protein chromophore and its application in latent fingerprint imaging. The fluorescent probe can be dissolved in water and can rapidly image the latent fingerprint on the object within 30 seconds through ultrasonic atomization. It is not affected by the collection background and will not affect the latent fingerprint.

[0006] However, the above latent fingerprint developers all have some defects during use. For example, the AIE functional molecules disclosed in patent CN112852409A are not water-soluble and need to be dispersed in water with the help of surfactants. The non-dissolved AIE functional molecule particles are large, which can easily cause uneven imaging effects. Moreover, the use of surfactants can easily damage fingerprint details, resulting in reduced imaging resolution. The latent fingerprint developers disclosed in patents CN112852409A and CN116003380A both need to implement latent fingerprint imaging by immersion. Due to the restriction of container volume, large objects or vertical surfaces are difficult to implement latent fingerprint imaging in situ by immersion. The latent fingerprint developer disclosed in patent CN113582931A uses an ultrasonic atomizer to implement latent fingerprint imaging by spraying. However, the 3-level fingerprint details cannot be directly captured using a digital camera or mobile phone, and the analysis and identification of the 3-level fingerprint details can only be completed with the help of an optical microscope. Summary of the invention

[0007] The present invention aims to overcome the shortcomings of the prior art and provide a water-soluble AIE functional molecule and a preparation method thereof, and use the same as a developer for latent fingerprint imaging. The developer has a simple preparation method, high aggregated luminescence efficiency, fast latent fingerprint imaging speed, high detection sensitivity and imaging resolution, and has excellent latent fingerprint imaging effects on strong self-luminous substrates, dark substrates, rough surface substrates, semi-adsorbent substrates and adsorbent substrates.

[0008] The present invention also provides an application of a water-soluble AIE functional molecule in latent fingerprint imaging.

[0009] To solve the above technical problems, the present invention is achieved as follows:

[0010] A water-soluble AIE functional molecule has the following general structural formula:

[0011]

[0012] Among them, R1 is

[0013]

[0014] Ar1 is an onium salt containing pyridine, quinoline or isoquinoline.

[0015] Further, Ar1 is:

[0016]

[0017] Where R2 is:

[0018]

[0019] The X is Cl, Br or I; and the n is any natural number between 0 and 10.

[0020] Further, Ar1 is:

[0021] R2 is n is 0, 1 or 2.

[0022] Further, the R1 is

[0023] Further, the R1 is Ar1 is: The preparation method of the water-soluble AIE functional molecule comprises the following steps:

[0024] (1) Synthesis of CziQn

[0025] To a mixed solution of tetrahydrofuran and deionized water, 6-bromoisoquinoline, K2CO3, Pd(PPh3)4 and (9-phenyl-9H-carbazole-3-yl)boric acid were added in sequence, and the mixture was stirred and refluxed for reaction; after the reaction, saturated brine was added and the mixture was extracted, the organic phases were combined, and separated by column chromatography to obtain CziQn;

[0026] (2) Synthesis of CziQn-OH

[0027] CziQn and 2-bromoethanol were added to acetonitrile and stirred for reaction. After the reaction, the solvent was removed by rotary evaporation and separated by column chromatography to obtain the target product, a water-soluble AIE functional molecule CziQn-OH.

[0028] Furthermore, in step (1), the volume ratio of tetrahydrofuran to deionized water is 3:1; the reaction is stirred and refluxed under a nitrogen atmosphere for 24 hours; and in step (2), the reaction is stirred and refluxed under a nitrogen atmosphere for 24 hours at 90°C.

[0029] Furthermore, in step (1) and step (2), the eluent for column chromatography separation is a mixture of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol is 10 to 100:1.

[0030] The application of the above-mentioned water-soluble AIE functional molecules in latent fingerprint development can be implemented according to the following steps:

[0031] (1) adding water-soluble AIE functional molecules to deionized water and dissolving them to obtain a latent fingerprint developer;

[0032] (2) Add the prepared water-soluble AIE functional molecule latent fingerprint developer into the medicine cup of the compressed atomizer, spray the nozzle of the medicine cup on the surface of the matrix where the latent fingerprint is located, and then perform latent fingerprint imaging and latent fingerprint luminescence search under ultraviolet light.

[0033] Furthermore, the substrate is one of stainless steel, glass, ceramic, wood, leather, plastic, copper or paper.

[0034] The water-soluble latent fingerprint developer of the present invention has a simple preparation method and high aggregated luminescence efficiency. The developer prepared with water as solvent can be sprayed with a compressed atomizer to implement latent fingerprint imaging on a variety of substrates. The latent fingerprint imaging can be completed within 10 seconds, the imaging speed is fast, and it has excellent latent fingerprint imaging effects on strong self-luminous substrates, dark substrates, rough surface substrates, semi-adsorbent substrates and adsorbent substrates. The detection sensitivity and imaging resolution are high, it is non-toxic and harmless, and has practical application value. It can replace traditional black developer powder and silver developer powder for the rapid extraction of fingerprint evidence at the crime scene.

[0035] The present invention will be described in detail below through specific examples. These examples are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be subject to the definition of the attached claims. Unless otherwise specified, the various reagents and materials used in the present invention can be purchased from the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the synthesis route of the AIE functional molecule prepared in Example 1 of the present invention.

[0037] Figure 2 The fluorescence emission spectra of the AIE functional molecules prepared in Example 1 of the present invention in water with different acetonitrile contents.

[0038] Figure 3 This is a latent fingerprint imaging image of a water-soluble AIE functional molecule latent fingerprint developer prepared in Example 1 of the present invention on a stainless steel product based on a compression atomizer.

[0039] Figure 4 This is a latent fingerprint imaging diagram of the latent fingerprint developer of the water-soluble AIE functional molecule prepared in Example 1 of the present invention on a glass product based on a compression atomizer.

[0040] Figure 5 This is a latent fingerprint developer of a water-soluble AIE functional molecule prepared in Example 1 of the present invention, based on a compression atomizer and imaged on a ceramic product using a latent fingerprint.

[0041] Figure 6This is a latent fingerprint developer of a water-soluble AIE functional molecule prepared in Example 1 of the present invention, which is an imaging diagram of a latent fingerprint on a wood product based on a compression atomizer.

[0042] Figure 7 The latent fingerprint developer of the water-soluble AIE functional molecule prepared in Example 1 of the present invention is an image of a latent fingerprint on a leather product based on a compression atomizer.

[0043] Figure 8 This is a latent fingerprint developer of a water-soluble AIE functional molecule prepared in Example 1 of the present invention, based on a compression atomizer and imaged on a plastic product using a latent fingerprint.

[0044] Fig. 9 This is a latent fingerprint developer of a water-soluble AIE functional molecule prepared in Example 1 of the present invention, which is an imaging diagram of a latent fingerprint on a copper product based on a compression atomizer.

[0045] Fig.10 This is a latent fingerprint developer of a water-soluble AIE functional molecule prepared in Example 1 of the present invention, based on a compression atomizer and imaged on a paper product using a latent fingerprint.

[0046] Fig.11 Fingerprint detail analysis diagram of the latent fingerprint developer of the water-soluble AIE functional molecule prepared in Example 1 of the present invention based on the imaging fingerprint photos on stainless steel products, copper products, and paper products using a compressed atomizer.

[0047] Fig.12 This is a fragment diagram of the latent fingerprint search on a plastic product based on a compressed atomizer using the latent fingerprint developer of the water-soluble AIE functional molecule prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0048] Example 1

[0049] A water-soluble AIE functional molecule, whose name is abbreviated as CziQn-OH, wherein R1 is Arl is n is 2. Its synthesis path is as follows Figure 1 As shown, the following steps are included:

[0050] (1) Synthesis of CziQn: 6-bromoisoquinoline (2.0 mmol, 0.414 g), K2CO3 (4.0 mmol, 0.552 g), Pd(PPh3)4 (5.0 mol%, 0.1 mmol, 0.115 g) and (9-phenyl-9H-carbazole-3-yl)boric acid (2.0 mmol, 0.574 g) were added to a mixed solution of tetrahydrofuran / deionized water (30 mL, 3:1 v:v) in sequence; the mixed solution was stirred and refluxed under nitrogen atmosphere for 24 hours. After the reaction, saturated salt (15 mL) was added, and the mixture was extracted with ethyl acetate (3×15 mL). The organic phases were combined and separated by column chromatography, and the eluent was dichloromethane / methanol (10:1, v:v). The obtained CziQn was an off-white powder with a yield of 87.7%. 1 H NMR (400MHz, Chloroform-d) δ9.29 (s, 1H), 8.55 (d, J = 5.8Hz, 1H), 8.49 (d, J = 1.5Hz, 1H), 8.23 ​​(d, 1H), 8.12-8.06 (m, 2H), 8.02 (dd, J = 8.5 , 1.8Hz, 1H), 7.78 (dd, J=8.5, 1.8Hz, 1H), 7.74 (d, J=5.8Hz, 1H), 7.67-7.58 (m, 4H), 7.53-7.50 (m, 2H), 7.47-7.43 (m, 2H), 7.34 (ddd, 1H). 13 C NMR (101MHz, Chloroform-d) δ152.1, 144.2, 142.9, 141.5, 140.9, 137.5, 136.5, 132.1, 130.0, 128.2, 127.8, 127.7, 1 27.4, 127.1, 126.5, 125.7, 124.1, 123.8, 123.3, 120.8, 120.4, 120.3, 119.5, 110.4, 110.1.HRMS (ESI): m / zcalc.for C 27 H 18 N2, 370.14700 [M] + , found: 370.14645[M] + .

[0051] (2) Synthesis of CziQn-OH: CziQn (1.0 mmol, 0.370 g) and 2-bromoethanol (10.0 mmol, 1.240 g, 0.710 mL) were added to CH3CN (25 mL), and the mixed solution was stirred at 90°C for 24 hours under a nitrogen atmosphere. After the reaction, the solvent was removed by rotary evaporation, and the mixture was separated by column chromatography with dichloromethane / methanol (10:1, V:V) as the eluent. The obtained CziQn-OH was a bright yellow powder with a yield of 50.7%. 1 H NMR (400MHz, DMSO-d6) δ9.97 (s, 1H), 9.00 (s, 1H), 8.86-8.70 (m, 2H), 8.65-8.54 (m, 4H), 8.42 (d, 1H), 8.08 (dq, 1H), 7.78-7.64(m, 4H), 7.63-7.45(m, 2H), 7.46-7.34(m, 2H), 5.30(t, 1H), 4.77(t, 2H), 3.98(q, 2H). 13 C NMR (101MHz, DMSO) δ149.5, 148.2, 140.9, 137.7, 136.4, 135.5, 130.9, 130.3, 130.2, 129.4, 128.1, 126.7, 126.1 , 125.7, 125.2, 123.8, 123.2, 122.8, 121.0, 120.7, 120.4, 110.6, 110.0, 104.3, 99.5, 62.9, 60.0.HRMS (ESI): m / z calc.for C 29 H 23 BrN2O, 494.09938[M] + , found: 494.09883[M] + .

[0052] The preparation method of the latent fingerprint developer of the water-soluble AIE functional molecule and the latent fingerprint imaging method in Example 1 of the present invention are as follows:

[0053] (1) Prepare an aqueous solution of a water-soluble AIE functional molecule CziQn-OH with a concentration of 100 μM as a latent fingerprint developer. CziQn-OH (4.95 mg) was added to deionized water (100 mL) and fully dissolved to obtain a latent fingerprint developer.

[0054] (2) The prepared water-soluble AIE functional molecule CziQn-OH latent fingerprint developer with a concentration of 100 μM was added into the medicine cup of the compressed atomizer, and the nozzle of the medicine cup was sprayed on the surface of the matrix where the latent fingerprint was located, and then the fingerprint was observed and photographed with high resolution under ultraviolet light.

[0055] Beneficial effects of the present invention:

[0056] Figure 2 This is the fluorescence emission spectrum of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention in water with different acetonitrile contents. When the acetonitrile content increases from 0% to 90%, the fluorescence intensity gradually increases. Figure 2 It can be seen that with the increase of acetonitrile content in the solvent system, the solubility of CziQn-OH decreases and aggregation occurs, and the fluorescence is significantly enhanced, showing AIE characteristics.

[0057] Figure 3 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a stainless steel product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present 3-level details such as pores and fingerprint ridge edge details.

[0058] Figure 4 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a glass product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present 3-level details such as pores and fingerprint ridge edge details.

[0059] Figure 5 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a ceramic product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present 3-level details such as pores and fingerprint ridge edge details.

[0060] Figure 6 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a wood product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present the second-level details such as the bifurcation and end point of the fingerprint.

[0061] Figure 7 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a leather product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present the second-level details such as the bifurcation and end point of the fingerprint.

[0062] Figure 8This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a plastic product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present 3-level details such as pores and fingerprint ridge edge details.

[0063] Fig. 9 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a copper product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present 3-level details such as pores and fingerprint ridge edge details.

[0064] Fig.10 This is an imaged fingerprint photograph of a latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a paper product via a compression atomizer. The imaged fingerprint has high contrast and high resolution, and can clearly present 3-level details such as pores and fingerprint ridge edge details.

[0065] Fig.11 This is a fingerprint detail analysis diagram of an imaged fingerprint photograph of a latent fingerprint developer of a water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention sprayed on a stainless steel product, a copper product, and a paper product by a compression atomizer. Level 1 details such as the center point and the triangulation point, level 2 details such as the ridge fold, the ridge end point, and the ridge bifurcation, and level 3 details such as the pores and ridge edge details are clearly visible; level 3 details such as the pore spacing, the ridge width, and the ridge angle can be accurately measured.

[0066] Fig.12 This is a screenshot of the latent fingerprint developer of the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention being sprayed on a plastic product by a compressed atomizer to perform a latent fingerprint luminescence search. The nozzle of the medicine cup is continuously sprayed on the plastic surface where the latent fingerprint is located to perform a latent fingerprint luminescence search. The atomized airflow continuously sweeps the surface of the substrate and then evenly diffuses around the surface to form an area of ​​about 0.0314m 2 The latent fingerprints in the purge area are stained due to the continuous contact with the atomized droplets. Moving the atomized gas source can increase the purge area and change the purge position to complete the latent fingerprint luminescence search process. Fig.12As shown, the latent fingerprint on the plastic surface is gradually dyed under the atomized air flow, and an enhanced luminescent signal is presented in real time. There is sufficient contrast between the luminescent signal of the imaged fingerprint and the matrix, and the naked eye can clearly identify it. The search and imaging of the entire latent palm print in the purge area can be quickly completed within 90 seconds. Compared with the traditional latent fingerprint search method, the latent fingerprint luminescent search based on the water-soluble AIE functional molecule CziQn-OH prepared in Example 1 of the present invention effectively overcomes the interference of objective factors such as the detection light angle, matrix material, background color, etc., and avoids the constraints of subjective factors such as the insight and practical experience of criminal investigators. Therefore, the efficiency of latent fingerprint search can be significantly improved, and the search process is more comprehensive and thorough.

[0067] Compared with the existing technology, the latent fingerprint developer of the present invention is not only simple in preparation process and convenient in operation, but also has low biological toxicity, fast developing speed and high imaging clarity. The outstanding advantage is that the consumption is small (0.26mg / m 2 ), without the need for pre- and post-processing, in-situ latent fingerprint imaging can be achieved at the crime scene, and without the need for large optical microscope equipment, a common mobile phone can be used to directly capture the three-level fingerprint details of the imaged fingerprint and complete the fingerprint detail analysis, which is suitable for various scenarios. The present invention realizes a method for preparing a latent fingerprint developer based on water-soluble AIE functional molecules and realizes latent fingerprint imaging and latent fingerprint luminescence search through a compressed atomizer, which has a huge impact on the development of latent fingerprint imaging technology and has practical application value.

[0068] Those skilled in the art should understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A water-soluble AIE functional molecule, characterized in that: It has the following general structural formula: Where R1 is: Ar1 is an onium salt containing pyridine, quinoline or isoquinoline.

2. The water-soluble AIE functional molecule according to claim 1, characterized in that: The Ar1 is: Where R2 is: The X is Cl, Br or I; and the n is any natural number between 0 and 10.

3. The water-soluble AIE functional molecule according to claim 2, characterized in that: The Ar1 is: R2 is n is 0, 1 or 2.

4. The water-soluble AIE functional molecule according to claim 2, characterized in that: The R1 is:

5. The water-soluble AIE functional molecule according to claim 3, characterized in that: The R1 is: Ar1 is:

6. A method for preparing a water-soluble AIE functional molecule as claimed in claim 5, characterized in that: The steps include: (1) Synthesis of CziQn To a mixed solution of tetrahydrofuran and deionized water, 6-bromoisoquinoline, K2CO3, Pd(PPh3)4 and (9-phenyl-9H-carbazole-3-yl)boric acid were added in sequence, and the mixture was stirred and refluxed for reaction; after the reaction, saturated brine was added and the mixture was extracted, the organic phases were combined, and separated by column chromatography to obtain CziQn; (2) Synthesis of CziQn-OH CziQn and 2-bromoethanol were added to acetonitrile and stirred for reaction. After the reaction, the solvent was removed by rotary evaporation and separated by column chromatography to obtain the target product, a water-soluble AIE functional molecule CziQn-OH.

7. The method for preparing a water-soluble AIE functional molecule according to claim 6, characterized in that: In step (1), the volume ratio of tetrahydrofuran to deionized water is 3:1; the mixture is stirred and refluxed under a nitrogen atmosphere for 24 hours; in step (2), the mixture is stirred and reacted at 90° C. under a nitrogen atmosphere for 24 hours.

8. The method for preparing a water-soluble AIE functional molecule according to claim 7, characterized in that: In step (1) and step (2), the eluent for column chromatography separation is a mixture of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol is 10 to 100:

1.

9. A use of the water-soluble AIE functional molecule according to any one of claims 1 to 5 in latent fingerprint development, characterized in that: Follow these steps to implement: (1) adding a water-soluble AIE functional molecule to deionized water and dissolving the molecule to obtain a water-soluble AIE functional molecule latent fingerprint developer; (2) Add the prepared water-soluble AIE functional molecule latent fingerprint developer into the medicine cup of the compressed atomizer, spray the nozzle of the medicine cup on the surface of the matrix where the latent fingerprint is located, and then perform latent fingerprint imaging and latent fingerprint luminescence search under ultraviolet light.

10. The use of the water-soluble AIE functional molecule in latent fingerprint imaging according to claim 9, characterized in that: The substrate is one of stainless steel, glass, ceramic, wood, leather, plastic, copper or paper.

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