A binuclear sub-copper cluster luminescent material based on chelating phosphine ligand and fluorescence sensing thereof

Abstract

The application discloses a kind of based on chelating phosphine ligand Binuclear cuprous cluster luminescent material and its preparation method, and the sensing application of the material to pyridine and cyclohexylamine VOC;The luminescent material structural formula of the application is (Xantphos) Cu2I2 (4-PBO) 2, wherein Xantphos is electric neutral double phosphine ligand 4,5-bis (diphenylphosphine) -9,9-dimethyl xanthene, and 4-PBO is nitrogen-containing ligand 4- (2-benzoxazole) pyridine;It is prepared by coordination reaction of CuI and ligand by mechanical ball milling;The luminescent intensity of material itself is strong, and can be used as luminescent material;And after the material is placed in pyridine or cyclohexylamine atmosphere, different fluorescence sensing response characteristics of fluorescence enhancement and discoloration and fluorescence quenching are presented soon respectively;The material is easy to prepare, and solubility and stability are very good, and it is also easy to prepare into paper-based load or polymer-doped fluorescent sensing film, and the film also shows the fluorescence sensing performance of quick and selective response and sensitive identification.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, to the field of photoluminescent materials, and particularly to the field of fluorescent sensing materials. Background Technology

[0002] Volatile organic compounds (VOCs) are numerous, unstable, and ubiquitous. They include both anthropogenic chemical compounds and naturally occurring ones. Most VOCs are emitted as vapors. In my country and many other countries, anthropogenic VOC emissions are subject to legal sanctions. Although harmful VOCs generally do not have acute toxicity, exposure to different concentrations of VOCs over a longer period can still have varying degrees of health effects. However, because VOC concentrations in the environment are usually low, and symptoms often develop slowly and are difficult to detect, research on VOCs and their effects still faces many difficulties and inconveniences.

[0003] However, with the rapid development of the national economy, VOC utilization or emissions are widespread in various industries, such as the petrochemical industry and the decoration industry, leading to numerous air pollution problems. For example, the extensive use of various organic / polymer building and decoration materials in the real estate industry has resulted in indoor air pollution, a problem that has garnered significant attention. In fact, VOCs are a major factor in indoor air pollution, with specific components including benzene compounds, organochlorides, Freon series, and pyridine compounds. Their sources are primarily interior decoration materials and furniture, such as paints, wallpapers, floor tiles, insulation materials, and adhesives. Therefore, understanding the VOC situation in the air and conducting VOC detection / testing is crucial. Existing methods include gas chromatography (GC), high-performance liquid chromatography (HPLC), membrane technology for treating volatile organic compounds, instrumental methods for VOC determination, and chemical methods for analyzing volatile organic compounds. However, these methods have certain drawbacks, such as difficulties in miniaturizing and portability of instruments, complex testing procedures, high costs, long testing times, sample consumption, and the generation of secondary emissions pollution.

[0004] Compared to traditional detection methods, fluorescence sensing is gaining increasing attention, with ongoing research and development efforts. Fluorescence sensors offer advantages such as high sensitivity, rich signal acquisition, easy miniaturization, non-destructive sampling, and ease of use, and their development is steadily progressing towards widespread practical application. Fluorescence sensors are mainly divided into two categories: thin-film fluorescence sensors that are easy to reuse and can respond to gaseous substances, and homogeneous fluorescence sensors used in solutions. The main structure of a fluorescence sensor typically consists of three parts: a receiver for the foreign substance, a reporter, and a connector. In the entire fluorescence sensor structure, the role of the receiver is self-evident; it is responsible for receiving foreign molecules and converting signals. Therefore, the selection and fabrication process of the receiver material (i.e., the sensitive material) are crucial, directly determining the sensor's performance and application range.

[0005] Existing luminescent materials fall into several categories: biological, inorganic, and organic, each with its own advantages and disadvantages. Biomaterials hold a prominent position in biomonitoring, but face significant limitations in other fields. Inorganic materials, due to their inherent physical properties, have good potential in pressure and temperature sensing, but encounter problems in gas and water source detection. This may be because, while inorganic powders exhibit good stability, their dense internal structure makes the luminescent centers difficult to influence by the external atmosphere. Therefore, only reports exist on sensing a few small molecules such as oxygen (Sensors And Actuators B-Chemical 2018, 254, 578-587), and no reports have been found on fluorescence sensing of VOCs. Organic molecules (pure organic materials), on the other hand, possess diverse structures and properties, facilitating design and optimization, and some reports on VOC fluorescence sensing have already been published. For example, based on the fluorescence quenching mechanism of intermolecular charge transfer (CT), Zhang L. et al. from the University of Utah reported in 2007 the sensing detection of electron-deficient nitrobenzene explosives, using p-type organic semiconductors as the fluorescent material (Journal of the American Chemical Society 2007, 129(22), 6978-6979). However, the fluorescence of organic materials is greatly affected by molecular stacking, with aggregation-induced fluorescence quenching (ACQ) being the most prominent manifestation. Overall, the existence of problems such as the stability and reliability of organic materials still limits their development.

[0006] Existing research reports show that complexes can form stable hybrid materials through coordination hybridization of inorganic and organic materials, and can exhibit fluorescence sensing functions. Therefore, it is a good solution that combines the advantages of inorganic and organic materials. Wenger reviewed the vapor-induced color change phenomenon of complexes and its application prospects in VOC sensing, predicting that it is a simple and inexpensive solution (Chemical Reviews 2013, 113(5), 3686-3733). However, as mentioned in the article, researchers in this field usually only study the molecular mechanism of the phenomenon, while ignoring the quantitative and inexpensive application requirements of actual sensing detection. It is particularly important to note that the platinum and gold used in the currently reported complexes are expensive. To meet the inexpensive requirements of applications, we must start with common metals. Compared with other metals, copper has advantages such as low cost, environmental friendliness, and non-toxicity. Moreover, my country has abundant copper resources, ranking third in the world. Current research indicates that cuprous complexes are not only based on inexpensive metals but also exhibit excellent luminescence properties. Furthermore, these properties can be structurally modulated (e.g., by adjusting emission wavelength and quantum yield). Therefore, it can be inferred that cuprous complexes represent a promising molecular platform for VOC fluorescence sensing. The key challenge lies in identifying and developing cuprous complex sensing materials with VOC fluorescence responsiveness, thereby promoting the widespread application of VOC fluorescence sensing technology. Summary of the Invention

[0007] The purpose of this invention is to provide a novel binuclear cuprous iodide cluster complex luminescent material based on chelated phosphine ligands, its preparation method, and its applications, as well as its sensing application for pyridine and cyclohexylamine VOCs. The thermally stable cuprous iodide complex luminescent material is conveniently and inexpensively prepared by coordinating cuprous iodide with two ligands under mechanical ball milling conditions. Furthermore, it is found that this material exhibits rapid and selective fluorescence responses in pyridine and cyclohexylamine atmospheres.

[0008] One of the technical solutions of this invention is to provide a novel binuclear cuprous iodide cluster complex luminescent material, which is obtained by coordination reaction of CuI with chelated phosphine ligand Xantphos and end-group nitrogen-containing ligand 4-PBO under mechanical ball milling conditions. Its molecular structure is (Xantphos)Cu2I2(4-PBO)2, where Xantphos is an electrically neutral bisphosphine ligand 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene, and 4-PBO is a nitrogen-containing ligand 4-(2-benzoxazole)pyridine.

[0009] The binuclear cuprous iodide cluster complex luminescent material is monoclinic, space group P21 / m, and its unit cell parameters are as follows: α=90°, β=111.738(16)°, γ=90°, Z = 2, D C =1.601g / cm 3 The material has an orange crystal color; its structure is a binuclear neutral complex, with two cuprous ions using different tetrahedral coordination modes and forming a bitetrahedral structure with shared edges through two bridging iodide ions; one cuprous ion uses a CuI₂P₂ tetrahedral coordination mode, where the two I ions are bridging iodide ions and the two P ions come from a bisphosphine ligand, Xantphos; the other cuprous ion uses a CuI₂N₂ tetrahedral coordination mode, where the two I ions are bridging iodide ions and the two N ions come from two nitrogen-containing ligands, 4-PBO; and there are strong supramolecular interactions between adjacent molecules, one of which is the intermolecular CH···π interaction formed by the two bisphosphine ligands in adjacent molecules through benzene rings and oxanthracene rings, and the other is the strong intermolecular π···π stacking interaction formed by the two 4-PBO ligands in adjacent molecules through benzene rings and benzoxazole rings, all of which increase the structural rigidity of the material; its molecular structure is shown in formula (I):

[0010]

[0011] The binuclear cuprous iodide cluster complex luminescent material exhibits as a broadband excitation high-efficiency luminescent phosphor, emitting strong red fluorescence under ultraviolet and visible light excitation in the wavelength range of 300 to 550 nanometers. Its maximum emission wavelength is 645 nm, and its color coordinates are (0.6197, 0.3788). It can be used as a photoluminescent red light material or as the red light material of the luminescent layer in electroluminescent devices composed of multilayer organic materials.

[0012] The second technical solution of this invention provides a method for preparing a binuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2. This preparation method involves a complete coordination reaction between CuI and ligands Xantphos and 4-PBO under mechanical ball milling conditions, ultimately yielding the product powder. The specific implementation scheme consists of four steps:

[0013] (1) Weigh CuI powder and powders of ligands Xantphos and 4-PBO at room temperature and add them to a ball mill jar;

[0014] (2) Add grinding balls to the grinding jar at a ball-to-material ratio of 70:1, and then add 3 mL of acetonitrile;

[0015] (3) Place the ball mill jar into the ball mill, set the ball mill speed to 160 rpm, and mill for 4 hours;

[0016] (4) After ball milling, place the ball milling jar in a vacuum oven at 40°C and dry it. The resulting powder is the product.

[0017] (5) The molar ratio of the three reactants CuI:Xantphos:4-PBO is 1:2:2, and the ball mill jar is a 50 mL agate jar.

[0018] The third technical solution of the present invention is to provide a fluorescence sensing application of a binuclear cuprous iodide cluster complex luminescent material (Xantphos)Cu2I2(4-PBO)2; when the luminescent material (Xantphos)Cu2I2(4-PBO)2 is placed in an environment containing pyridine VOC vapor, it will rapidly exhibit a significantly enhanced luminescence effect, and its maximum emission wavelength will undergo a significant blue shift (the new maximum emission wavelength is 510nm), and the emission will change from the original red to blue-green. Therefore, it can be used as a sensing material for detecting pyridine VOCs.

[0019] The fourth technical solution of this invention is to provide an application of a fluorescent sensing film based on a binuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2. When the fluorescent sensing film is placed in an environment containing pyridine vapor, it rapidly exhibits a significantly enhanced luminescence effect, and its maximum emission wavelength undergoes a significant blue shift (the new maximum emission wavelength is 510 nm), with the emission changing from the original red to blue-green. Therefore, it can be used as a sensing film for detecting pyridine VOCs. In addition, when the fluorescent sensing film is placed in an environment containing cyclohexylamine vapor, it rapidly exhibits a significant fluorescence quenching response effect. However, this fluorescent sensing film does not show obvious fluorescence response behavior for many VOC vapors such as triethylamine, trimethylamine, ethanolamine, monomethylamine, benzene, 2-phenylpyridine, 3-phenylpyridine, 2-aminopyridine, 4-hydroxypyridine, diethylenetriamine, and ammonia. Therefore, it can also be used as a selective fluorescent sensing film for detecting cyclohexylamine VOCs.

[0020] The fifth technical solution of this invention provides a method for preparing a paper-based fluorescent sensing film based on a dinuclear cuprous iodide cluster complex luminescent material (Xantphos)Cu2I2(4-PBO)2. This preparation method involves dissolving the dinuclear cuprous iodide complex luminescent material (Xantphos)Cu2I2(4-PBO)2 and then coating the solution onto a cellulose film. The specific implementation scheme consists of four steps:

[0021] (1) The luminescent material (Xantphos) Cu2I2(4-PBO)2 powder was dissolved in dichloromethane at room temperature;

[0022] (2) The cellulose film is made into the shape that is convenient for application and becomes the test paper base paper;

[0023] (3) The above-mentioned luminescent material (Xantphos) Cu2I2(4-PBO)2 solution was coated onto the test paper base at room temperature;

[0024] (4) Finally, the coated test paper is dried under vacuum conditions. After drying, the paper-based fluorescent sensing film is obtained.

[0025] The sixth technical solution of this invention provides a method for preparing a fluorescent sensing thin film doped with a dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2. This is achieved by embedding the dinuclear cuprous iodide complex luminescent material (Xantphos) Cu2I2(4-PBO)2 in PMMA (polymethyl methacrylate), and the specific implementation involves four steps:

[0026] (1) Dissolve solid PMMA in dichloromethane at room temperature;

[0027] (2) The luminescent material (Xantphos) Cu2I2(4-PBO)2 powder was dissolved in dichloromethane at room temperature;

[0028] (3) Mix the two solutions and stir to allow them to react fully to obtain a clear solution A;

[0029] (4) At room temperature, spin-coat the clear solution A onto a quartz plate, a metal substrate, or onto a substrate such as test paper, and then dry it to obtain a doped fluorescent sensing film.

[0030] The beneficial effects of this invention are, firstly, the provided binuclear cuprous iodide cluster complex luminescent material (Xantphos)Cu2I2(4-PBO)2, in which the presence of the large-volume chelating phosphine ligand Xantphos and the large delocalized ligand 4-PBO based on benzoxazole, as well as the rigid Cu2I2 binuclear cuprous iodide cluster core, all contribute to the luminescence of the excited state. Quantum chemical calculations show that the luminescence of the material originates from the charge transfer excited state from the cluster core to the nitrogen-containing ligand, exhibiting significant charge separation characteristics in the excited state and effectively avoiding the common problem of excited-state configuration distortion in cuprous complexes, thus promoting the luminescence of the material. In addition, there are strong supramolecular interactions between adjacent molecules in the structure of this material, which increases the internal structural rigidity of the material and also makes the molecular structure exhibit good fluorescence emission performance, providing a foundation for subsequent sensing performance research. This complex material has the advantages of being inexpensive and easy to purify, and also has good solubility and thermal stability, providing technical support for the further application of the material.

[0031] The beneficial effects of this invention are, secondly, the selective fluorescence sensing application of the dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 in response to pyridine, which can be completed rapidly in a short time; the fluorescence performance of this luminescent material after responding to pyridine is very good, and even a very small amount of material powder can emit strong fluorescence, so only a small amount of phosphor is needed in practical applications, which helps to reduce application costs, and the easy-to-operate doping method also facilitates cost control; when materials prepared by the same process are placed in a pyridine atmosphere, the sensing response characteristics of enhanced fluorescence and color change can be quickly observed; and its solubility and stability are very good, making it easy to use as a fluorescence sensing material.

[0032] The beneficial effects of this invention are further demonstrated by the selective fluorescence sensing application of the binuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 in response to cyclohexylamine. This response can be completed rapidly within a short time. The fluorescence of this luminescent material after responding to cyclohexylamine can be completely quenched, and the degree of quenching is directly related to the amount of cyclohexylamine. Moreover, the quenching response performance has good reversibility, making it easy to reuse the material and sensor, and also facilitating cost control in applications. Furthermore, when materials prepared by the same process are placed in a cyclohexylamine atmosphere, the fluorescence quenching sensing response characteristics can be quickly observed. In addition, its solubility, stability, and reversible response performance are all very good, making it easy to use as a fluorescence sensing material.

[0033] Another beneficial effect of this invention is the VOC sensing application of the paper-based fluorescent thin film based on the dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2. The use of this paper-based fluorescent thin film is as simple as that of ordinary gas detection test strips. In specific applications, after briefly placing the paper-based fluorescent thin film in an environment containing pyridine or cyclohexylamine, irradiating the film with an ultraviolet light source, rapid fluorescence enhancement and color change / fluorescence quenching phenomena can be observed. Furthermore, the increased VOC concentration exhibits an intensity-dependent fluorescence response, demonstrating reversible rapid response and sensitive fluorescence sensing performance. Therefore, it can be used as a portable fluorescent sensing test strip device for VOC detection. This fluorescent sensing thin film can be flexibly manufactured into various desired shapes, is very lightweight, extremely portable, and easy to prepare, providing technical support for the further application of luminescent materials.

[0034] Another beneficial effect of this invention is the VOC sensing application of the doped fluorescent thin film based on the dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2. This doped fluorescent thin film can be fabricated on various substrates such as quartz, plastic, and paper, or it can be directly deposited on the fiber optic port to make a fiber optic sensing probe. In specific applications, after the doped film is placed in an environment with pyridine or cyclohexylamine atmosphere for a short time, it is irradiated with an ultraviolet light source. A rapid fluorescence enhancement and color change / fluorescence quenching phenomenon can be observed. Furthermore, the increased VOC concentration shows an intensity-dependent fluorescence response effect, demonstrating reversible rapid response and sensitive fluorescence sensing performance. Therefore, it can be used as a sensitive film component for VOC detection in fiber optic sensors and the like.

[0035] The beneficial effects of this invention are that the method for preparing the binuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 and its sensing film has the advantages of simple process, simple equipment, simple and readily available raw materials, low production cost, high material preparation yield, and the ability to obtain a large number of products in a short time and facilitate promotion. Attached Figure Description

[0036] Figure 1 Crystalline independent unit structure of dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2.

[0037] Figure 2 Single-crystal structure diagram of the luminescent material Cu2I2(4-PBO)2 molecule of dinuclear cuprous iodide cluster complex (Xantphos).

[0038] Figure 3 Stacking diagram of the luminescent material Cu2I2(4-PBO)2 molecule in a single cell and its surrounding space.

[0039] Figure 4 X-ray powder diffraction patterns of the binuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2: (a) is the spectrum obtained by simulation based on the single crystal structure data in Example 2; (b) is the spectrum of the powder obtained in Example 1 of this invention.

[0040] Figure 5 FTIR spectrum of dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2.

[0041] Figure 6UV-Vis absorption spectrum of Xantphos Cu2I2(4-PBO)2, a binuclear cuprous iodide cluster complex luminescent material.

[0042] Figure 7 Fluorescence emission (PL-EM) spectrum of polycrystalline powder of dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 under ultraviolet light excitation at 365 nm.

[0043] Figure 8 Fluorescence excitation (PL-EX) spectrum of dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 polycrystalline powder at a monitored emission wavelength of 645 nm.

[0044] Figure 9 The frontier orbital diagram of the dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 molecule clearly shows the charge transfer characteristics from the cluster core to the nitrogen-containing ligand.

[0045] Figure 10 Fluorescence emission spectra of paper-based thin films loaded with dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 in a pyridine atmosphere before and after a certain response time.

[0046] Figure 11 A graph showing the shift (blue shift) in fluorescence emission wavelength of a paper-based thin film loaded with a binuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu2I2(4-PBO)2 during the response in a pyridine atmosphere.

[0047] Figure 12 The fluorescence emission intensity change spectrum of the polymer-based doped copper sub-cuprous cluster luminescent material (Xantphos) Cu2I2(4-PBO)2 fluorescent sensing film after a certain period of time in a cyclohexylamine atmosphere.

[0048] Figure 13 The time-kinetic curve of fluorescence quenching process of the polymer-based doped cuprous cluster luminescent material (Xantphos) Cu2I2(4-PBO)2 fluorescent sensing film in response to cyclohexylamine atmosphere.

[0049] Figure 14 Selective fluorescence quenching response diagram of the polymer-based doped copper sub-cuprous cluster luminescent material (Xantphos) Cu2I2(4-PBO)2 fluorescent sensing film to cyclohexylamine in various VOC atmospheres.

[0050] Figure 15The fluorescence enhancement response of the polymer-based doped cuprous cluster luminescent material (Xantphos) Cu2I2(4-PBO)2 fluorescent sensing film in different concentrations of pyridine atmosphere and the fitting curves obtained therefrom.

[0051] Figure 16 Fluorescence quenching response of polymer-based doped cuprous cluster luminescent material (Xantphos) Cu2I2(4-PBO)2 fluorescent sensing film in cyclohexylamine atmospheres of different concentrations and the fitting curves obtained therefrom. Detailed Implementation

[0052] The implementation process and material properties of this invention are illustrated by the following examples:

[0053] Example 1

[0054] Polycrystalline powder of a binuclear cuprous iodide cluster complex luminescent material (Xantphos)Cu2I2(4-PBO)2 was synthesized using Xantphos, cuprous iodide, and 4-PBO as raw materials according to the following method: 0.3 mmol of Xantphos, 0.6 mmol of cuprous iodide, and 0.6 mmol of 4-PBO were weighed and placed in a ball mill jar. 17 g of grinding balls (two types, 10 mm and 6 mm in diameter, were added to the jar, with 8 large balls and 14 small balls respectively) were added. Then, 3 ml of acetonitrile was added as a liquid grinding aid. The mixture was ball-milled at 160 rad / min for 4 h. After ball milling, it was dried in a vacuum oven at 40°C to obtain the polycrystalline powder product, with a yield (based on cuprous iodide) of 81.9%. When the complex luminescent material was placed in a pyridine atmosphere, a rapid change in fluorescence emission from red to blue-green was observed.

[0055] Example 2

[0056] Synthesis of single crystals of the dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu₂I₂(4-PBO)₂: 0.1 mmol (16.9 mg) of KI was completely dissolved in 2 mL of CH₃CN, resulting in a colorless and transparent solution, denoted as solution A. 0.1 mmol (57.8 mg) of Xantphos was completely dissolved in 2 mL of CH₂Cl₂, resulting in a colorless and transparent solution, denoted as solution B. 0.1 mmol (19.6 mg) of 4-PBO₄ was completely dissolved in 2 mL of CH₂Cl₂, resulting in a light brown and transparent solution, denoted as solution C. 0.1 mmol (37.3 mg) of [Cu(CH₃CN)₄]PF₆ was completely dissolved in 3 mL of CH₃CN, resulting in a milky blue and clear solution, denoted as solution D. Solution B was added to solution D, and then solution C was added immediately. The solution color changed from milky blue and clear to colorless and clear, then to brownish-yellow and clear. After reacting for 30 minutes, solution A was added, and the solution immediately turned brownish-yellow and turbid. The mixed solution was reacted on a stirrer for 1 hour and then filtered. The filtrate was concentrated by rotary evaporation (80 rad / min, room temperature). Rotary evaporation was stopped when precipitation was imminent. The filtrate was divided into two portions; one portion was added with n-hexane, and the other with isopropanol, using a slow-release method. Both samples were sealed with plastic wrap and sealing film and placed in a sample rack. After several days, a large number of light yellow and orange-red granular crystals were obtained in the test tube containing n-hexane. One orange-red granular crystal measuring 0.42 mm * 0.32 mm * 0.20 mm was selected for X-ray single-crystal structure analysis. The molecular structure diagram of this compound is shown in the attached figure. Figure 1 and Figure 2 Its unit cell packing structure is illustrated in the attached diagram. Figure 3 .

[0057] A series of tests were conducted on the pure-phase crystal sample of the dinuclear cuprous iodide cluster complex luminescent material (Xantphos) Cu₂I₂(4-PBO)₂. Steady-state fluorescence tests were performed on the crystal sample of this invention. The results showed that the material emitted strong red light under different excitation wavelengths in the wavelength range of 300 to 550 nm, with chromaticity coordinates of (0.6197, 0.3788). The specific excitation and emission spectra are attached. Figure 7 and attached Figure 8 As shown, this material can be applied to red light-emitting materials excited by various wavelengths, and can be used as a photoluminescent red light-emitting material, or as a red light-emitting layer material in electroluminescent devices composed of multilayer organic materials.

[0058] Example 3

[0059] Preparation and Atmospheric Response of a Fluorescent Sensing Film Loaded with a Dinuclear Cuprous Iodide Cluster Complex (Xantphos)Cu₂I₂(4-PBO)₂: 0.045 g of the luminescent material (Xantphos)Cu₂I₂(4-PBO)₂ was weighed and completely dissolved in 7 mL of dichloromethane. The solution was a clear, pale orange color and filtered. Cellulose films were cut to suitable sizes and shapes for subsequent applications and used as the base paper for test strips. A suitable amount of filtrate was taken and coated onto the base paper using printing, dip coating, or brushing. The coated test strips were dried under vacuum (60℃, 30 min). After drying, the fluorescent sensing film (fluorescent test strip) was obtained. The sensing film was then placed in a VOC environment to test its fluorescence spectrum. The results showed that when the fluorescent sensing film was placed in an environment containing pyridine vapor, it rapidly exhibited a significantly enhanced luminescence effect, and its maximum emission wavelength underwent a noticeable blue shift (the new maximum emission wavelength was 510 nm), with the emission changing from red to blue-green. Therefore, it can be used as a sensing film (test paper) for detecting pyridine VOCs. Furthermore, when the fluorescent sensing film was placed in an environment containing cyclohexylamine vapor, it rapidly exhibited a significant fluorescence quenching response. This paper-based fluorescent sensing film did not show significant fluorescence response behavior for many VOC vapors, including triethylamine, trimethylamine, ethanolamine, monomethylamine, benzene, 2-phenylpyridine, 3-phenylpyridine, 2-aminopyridine, 4-hydroxypyridine, diethylenetriamine, and ammonia. Therefore, it can also be used as a selective fluorescent sensing film (test paper) for detecting cyclohexylamine VOCs. (See...) Figure 10 , Figure 11 ).

[0060] Example 4

[0061] Preparation and Atmospheric Response of a Polymer-Doped Dinuclear Cuprous Iodide Cluster Complex Luminescent Film (Xantphos) Cu₂I₂(4-PBO)₂: 0.8 g of PMMA (polymethyl methacrylate, glass transition temperature: 105 °C) was completely dissolved in 9 mL of dichloromethane, resulting in a colorless, clear, and transparent solution. 0.040 g of the luminescent material (Xantphos) Cu₂I₂(4-PBO)₂ was completely dissolved in 6 mL of dichloromethane, resulting in a pale orange, clear, and transparent solution. The luminescent material solution was slowly introduced into the PMMA solution, resulting in a clear and transparent solution. The solution was spin-coated onto a clean quartz plate (1200 rad / min), dried (60 °C, 30 min), and then placed in a VOC environment to test the fluorescence spectrum. The results showed that when the fluorescent sensing film was placed in an environment containing pyridine vapor, it rapidly exhibited a significantly enhanced luminescence effect, and its maximum emission wavelength underwent a noticeable blue shift (the new maximum emission wavelength was 510 nm), with the emission changing from red to blue-green. Therefore, it can be used as a sensing film for detecting pyridine VOCs. Furthermore, when the fluorescent sensing film was placed in an environment containing cyclohexylamine vapor, it rapidly exhibited a significant fluorescence quenching response. This fluorescent sensing film did not show significant fluorescence response behavior for many VOC vapors, including triethylamine, trimethylamine, ethanolamine, monomethylamine, benzene, 2-phenylpyridine, 3-phenylpyridine, 2-aminopyridine, 4-hydroxypyridine, diethylenetriamine, and ammonia. Therefore, it can also be used as a selective fluorescent sensing film for detecting cyclohexylamine VOCs. (See...) Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 ).

[0062] Example 5

[0063] Preparation and Atmospheric Response of a Polymer-Doped Dinuclear Cuprous Iodide Cluster Complex Luminescent Film (Xantphos) Cu₂I₂(4-PBO)₂: 0.8 g of PMMA (polymethyl methacrylate, glass transition temperature: 105 °C) was completely dissolved in 9 mL of dichloromethane, resulting in a colorless, clear, and transparent solution. 0.040 g of the luminescent material (Xantphos) Cu₂I₂(4-PBO)₂ was completely dissolved in 6 mL of dichloromethane, resulting in a pale orange, clear, and transparent solution. The luminescent material solution was slowly introduced into the PMMA solution, resulting in a clear and transparent solution. The film was spin-coated (1200 rad / min) onto a clean aluminum alloy or other metal substrate, dried (60 °C, 30 min), and then placed in a VOC environment to test the fluorescence spectrum. The results showed that when the fluorescent sensing film was placed in an environment containing pyridine vapor, it rapidly exhibited a significantly enhanced luminescence effect, and its maximum emission wavelength underwent a noticeable blue shift (the new maximum emission wavelength was 510 nm), with the emission changing from red to blue-green. Therefore, it can be used as a sensing film for detecting pyridine VOCs. Furthermore, when the fluorescent sensing film was placed in an environment containing cyclohexylamine vapor, it rapidly exhibited a significant fluorescence quenching response. This fluorescent sensing film did not show significant fluorescence response behavior for many VOC vapors, including triethylamine, trimethylamine, ethanolamine, monomethylamine, benzene, 2-phenylpyridine, 3-phenylpyridine, 2-aminopyridine, 4-hydroxypyridine, diethylenetriamine, and ammonia. Therefore, it can also be used as a selective fluorescent sensing film for detecting cyclohexylamine VOCs. (See...) Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 ).

Claims

1. A method for preparing a binuclear cuprous cluster luminescent material based on chelated phosphine ligands, characterized in that: The structural formula of the dinuclear cuprous cluster luminescent material is (Xantphos)Cu2I2(4-PBO)2, where Xantphos is the electrically neutral bisphosphine ligand 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene, and 4-PBO is the nitrogen-containing ligand 4-(2-benzoxazole)pyridine. The dinuclear cuprous cluster luminescent material is monoclinic, space group P21 / m, with cell parameters a=9.9622(12) Å, b=23.114(2) Å, c=13.108(2) Å, α=90°, β=111.738(16)°, γ=90°, and V=2803.6(7) Å. 3 Z=2, D C =1.601 g / cm 3 The material has an orange crystal color; its structure is a binuclear neutral complex, with two cuprous ions using different tetrahedral coordination modes and forming a bitetrahedral structure with shared edges through two bridging iodide ions; one cuprous ion uses a CuI₂P₂ tetrahedral coordination mode, where the two I ions are bridging iodide ions and the two P ions come from a bisphosphine ligand, Xantphos; the other cuprous ion uses a CuI₂N₂ tetrahedral coordination mode, where the two I ions are bridging iodide ions and the two N ions come from two nitrogen-containing ligands, 4-PBO; and there are strong supramolecular interactions between adjacent molecules, one of which is the CH•••π interaction between the two bisphosphine ligands in adjacent molecules through a benzene ring and an oxanthracene ring, and the other is the strong π•••π stacking interaction between the two 4-PBO ligands in adjacent molecules through a benzene ring and a benzoxazole ring, all of which increase the structural rigidity of the material; its molecular structure is shown in formula (I): （I）； The preparation method of the dual-nuclear cuprous cluster luminescent material includes the following steps: (1) Weigh CuI powder and powders of ligands Xantphos and 4-PBO at room temperature and add them to a ball mill jar; (2) Add grinding balls to the grinding jar at a ball-to-material ratio of 70:1, and then add 3 mL of acetonitrile; (3) Place the ball mill jar into the ball mill, set the ball mill speed to 160 rpm, and mill for 4 hours; (4) After ball milling, place the ball milling jar in a vacuum oven at 40°C to dry it. The resulting crystalline powder is the product. (5) The molar ratio of the three reactants CuI : Xantphos : 4-PBO is 1 : 2 : 2, and the ball mill jar is a 50 mL agate jar.

2. An application of a fluorescent sensing thin film based on a dual-core copper subclustere cluster luminescent material, characterized in that: The fluorescent sensing film is prepared by dissolving the dinuclear cuprous cluster luminescent material (Xantphos) Cu₂I₂(4-PBO)₂ and coating it onto the test paper base, or by dissolving and embedding it in a polymer solution and then depositing it onto a quartz substrate. When the fluorescent sensing film is placed in an environment containing pyridine vapor, it rapidly exhibits a significantly enhanced luminescence effect, with a noticeable blue shift in its maximum emission wavelength to 510 nm. The emission changes from red to blue-green, thus making it suitable as a sensing film for detecting pyridine VOCs. Furthermore, when placed in an environment containing cyclohexylamine vapor, the fluorescent sensing film rapidly exhibits a significant fluorescence quenching response. However, the film does not show significant fluorescence response to triethylamine, trimethylamine, ethanolamine, monomethylamine, benzene, 2-phenylpyridine, 3-phenylpyridine, 2-aminopyridine, 4-hydroxypyridine, diethylenetriamine, or ammonia VOC vapors, thus making it suitable as a selective fluorescent sensing film for detecting cyclohexylamine VOCs. The dinuclear cuprous cluster luminescent material... The structure is (Xantphos)Cu2I2(4-PBO)2, where Xantphos is the electrically neutral bisphosphine ligand 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene, and 4-PBO is the nitrogen-containing ligand 4-(2-benzoxazole)pyridine; the binuclear cuprous cluster luminescent material is monoclinic, space group P21 / m, with cell parameters a=9.9622(12) Å, b=23.114(2) Å, c=13.108(2) Å, α=90°, β=111.738(16)°, γ=90°, V=2803.6(7) Å. 3 Z=2, D C =1.601 g / cm 3 The material has an orange crystal color; its structure is that of a binuclear neutral complex, with two cuprous ions using different tetrahedral coordination modes and forming a bitetrahedral structure connected by two bridging iodide ions; its molecular structure is shown in formula (I): （I）。 3. The application according to claim 2, wherein the method for preparing the paper-based fluorescent sensing film based on the dual-core copper sub-cluster luminescent material includes the following steps: (1) The luminescent material (Xantphos)Cu2I2(4-PBO)2 powder was dissolved in dichloromethane at room temperature; (2) The cellulose film is made into the shape that is convenient for application and becomes the test paper base paper; (3) The above-mentioned luminescent material (Xantphos) Cu2I2(4-PBO)2 solution was coated onto the test paper base paper at room temperature; (4) Finally, the coated test paper is dried under vacuum conditions. After drying, the paper-based fluorescent sensing film is obtained.

4. The application according to claim 2, wherein the method for preparing the polymer-based doped fluorescent sensing thin film based on the dual-core copper sub-cluster cluster luminescent material includes the following steps: (1) Dissolve solid PMMA in dichloromethane at room temperature; (2) The luminescent material (Xantphos)Cu2I2(4-PBO)2 powder was dissolved in dichloromethane at room temperature; (3) Mix the two solutions and stir to allow them to react fully to obtain a clear solution A; (4) At room temperature, spin-coat the clear solution A onto a quartz plate, a metal substrate, or onto the original paper substrate of the test paper, and then dry it to obtain the doped fluorescent sensing film.

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