A benzotriazine diradical compound, its preparation method, and its application in a solar interfacial evaporator.

Abstract

This invention belongs to the field of organic photothermal materials technology and its applications, specifically relating to a benzotriazine diradical compound, its preparation method, and its application in the light-absorbing layer of a solar interfacial evaporator. This invention constructs a series of small organic molecule compounds based on planarity and conjugation design using a classic synthetic route. The benzotriazine diradical small organic molecule compound prepared by this invention exhibits good thermal stability and excellent photothermal conversion capability, and can be used to prepare the light-absorbing layer of a solar interfacial evaporator. The light-absorbing layer of the solar interfacial evaporator prepared by this invention has ultra-high water evaporation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of organic photothermal new materials technology and its application, specifically involving a benzotriazine diradical compound, a method for preparing the compound, and its application in the light absorption layer of a solar interface evaporator. Background Technology

[0002] Photothermal materials are a class of materials capable of converting light energy into heat energy. Their working principle involves light irradiating the surface of the material, where photons are absorbed by electrons, causing them to transition from a lower energy level to a higher one. During the return journey to the lower energy level, nonradiative relaxation occurs, resulting in heat generation and achieving photothermal conversion. As an important energy material, photothermal materials have wide applications in various fields, such as solar energy utilization, photothermal therapy, temperature sensing, and photothermal catalysis. In recent years, significant progress has been made in the research of organic photothermal materials. For example, an increasing number of novel organic photothermal materials have been developed, among which small-molecule organic photothermal materials containing conjugated organic frameworks have become a focus of attention due to their good compatibility, stability, and high photothermal conversion efficiency. However, photothermal materials based on small organic molecules generally suffer from problems such as low temperature rise and low photothermal conversion efficiency. Quinone diradical molecules, on the other hand, typically possess high molecular conjugation and an extended π-electron system, which helps enhance light absorption. They can effectively convert light energy into heat energy through rapid electron transitions and energy transfer processes, thereby improving photothermal conversion efficiency. Therefore, by altering the structure, composition, and intermolecular interactions of diradical molecules, organic small molecules can be designed to regulate their photothermal properties, which can meet different application requirements and is crucial for the development of the photothermal field. Summary of the Invention

[0003] The present invention aims to provide a benzotriazine diradical organic small molecule compound, along with a corresponding preparation method and its application in the preparation of the light-absorbing layer of a solar interface evaporator.

[0004] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0005] The first aspect of this invention provides a benzotriazine diradical compound, the structural formula of which is shown in Formula 1:

[0006]

[0007] R is selected from any one of dimethylamino, diphenylamino, tert-butyl or isopropyl.

[0008] A second aspect of this invention provides a method for preparing the benzotriazine diradical compound described in the first aspect, comprising the following steps:

[0009] S1: Add compound A and compound B to tetrahydrofuran and mix well. Then add triethylamine and heat under reflux at 85℃~90℃ for 24~48h to separate the intermediate product.

[0010] S2: Dissolve the intermediate product obtained in step S1 in a small amount of dichloromethane, then add a large amount of ethanol, and then add 1,8-diazabicyclo[5.4.0]undec-7-ene. At the same time, air is introduced and the mixture is stirred while bubbling. After the reaction is completed, filter the mixture and wash the filter cake with ethyl acetate to obtain the benzotriazine diradical compound shown in Formula 1.

[0011] Wherein, the structural formula of compound A is selected from any one of formulas a-1, a-2, a-3, and a-4:

[0012]

[0013] The structural formula of compound B is shown in formula b:

[0014]

[0015] Preferably, in step S1, the molar ratio of compound A to compound B is (3-4):1; and the molar ratio of triethylamine to compound A is (1-3):1.

[0016] Preferably, in step S2, the molar ratio of 1,8-diazabicyclo[5.4.0]undec-7-ene to compound A is 1:(1-2).

[0017] Preferably, after the reaction in step S1 is completed, the reaction solution is cooled to room temperature, filtered, and the filtrate is collected; the solvent in the filtrate is removed by rotary evaporation under reduced pressure to obtain the intermediate product.

[0018] Furthermore, compound A is prepared by the following method:

[0019] Compound C and triphenylphosphine were added to acetonitrile, followed by carbon tetrachloride, and the mixture was stirred at room temperature. After the reaction was complete, the mixture was filtered, and the filtrate was purified to obtain compound A. The structural formula of compound C is selected from any one of formulas c-1, c-2, c-3, and c-4.

[0020]

[0021]

[0022] The molar ratio of compound C to triphenylphosphine is 1:(1-2), and the molar ratio of carbon tetrachloride to compound C is (1-2):1.

[0023] Compound C is obtained by amidation reaction of compound D and compound E. The specific preparation method is as follows: compound E and triethylamine are added to tetrahydrofuran, stirred in an ice-water bath for 10–15 min, then compound D is added to obtain a mixed solution; the mixture is naturally heated to room temperature and stirred for 18–24 h; after the reaction is complete, the mixture is filtered, the filtrate is collected, the solvent is evaporated to obtain a solid product, and the solid product is purified to obtain compound C; wherein, the structural formula of compound D is selected from any one of formulas d-1, d-2, d-3, and d-4, and the structural formula of compound E is shown in formula e.

[0024]

[0025] The third aspect of the present invention provides the application of the benzotriazine diradical compounds described in the first aspect above in the light-absorbing layer of a solar interface evaporator.

[0026] The light-absorbing layer of the solar interface evaporator is prepared by loading a benzotriazine diradical compound onto PU foam using a solution evaporation technique.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. This invention successfully prepared benzotriazine diradical compounds. The preparation process is simple, time-saving, and labor-saving, using inexpensive and readily available raw materials, thus reducing production costs. It provides ideas and methods for the design and preparation of Blatter diradicals. The benzotriazine diradical small molecule organic compounds prepared by this invention exhibit good thermal stability and excellent photothermal conversion capabilities, and can be used to prepare the light-absorbing layer of solar interfacial evaporators.

[0029] 2. The light absorption layer of the solar interface evaporator based on benzotriazine diradical compounds provided by this invention has ultra-high water evaporation efficiency and has high application value in the field of solar interface water evaporation. Attached Figure Description

[0030] Figure 1 For compound A with the structural formula shown in formula a-2 1 HNMR spectrum;

[0031] Figure 2 For compound C with the structural formula shown in formula c-2 1 HNMR spectrum;

[0032] Figure 3 The mass spectrum of the benzotriazine diradical compound prepared in Example 5;

[0033] Figure 4 The mass spectrum of the benzotriazine diradical compound prepared in Example 6;

[0034] Figure 5 The mass spectrum of the benzotriazine diradical compound prepared in Example 7;

[0035] Figure 6 The mass spectrum of the benzotriazine diradical compound prepared in Example 8;

[0036] Figure 7 The UV-absorbing spectra of the benzotriazine diradical compounds prepared in Examples 5-8 are shown below.

[0037] Figure 8 Thermogravimetric analysis (TGA) diagrams of the benzotriazine diradical compounds prepared in Examples 5-8 are shown.

[0038] Figure 9 Cyclic voltammetry diagrams of the benzotriazine diradical compounds prepared in Examples 5-8;

[0039] Figure 10 Photothermal properties of the benzotriazine diradical compounds prepared in Examples 5-8;

[0040] Figure 11 ESR diagrams of the benzotriazine diradical compounds prepared in Examples 5-8;

[0041] Figure 12 A schematic diagram of the structure of the light-absorbing layer of the solar interface evaporator prepared in Example 10;

[0042] Figure 13 Photothermal performance test diagram of the solar interface evaporator light absorption layer loaded with interface layer prepared in Example 10;

[0043] Figure 14 The evaporation performance of the light-absorbing layer of the solar interface evaporator prepared in Example 10 and its comparison with the performance of similar molecules are shown in the figure. Detailed Implementation

[0044] The following embodiments are only for further elaboration of the present invention. It should be noted that all techniques and scientific terms used in this invention, unless otherwise stated, have the same meaning as those in the technical field to which this invention pertains. Experimental methods in the following embodiments that do not specify specific conditions all employ conventional techniques in this technical field, or follow the conditions recommended by the manufacturer; reagents or instruments whose manufacturers are not specified are all commercially available conventional products, or can be prepared according to conventional techniques in this technical field.

[0045] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0046] Example 1

[0047] A method for preparing compound A with the structural formula shown in formula a-1, comprising the following specific steps:

[0048] (1) Add 5g (1eq) of compound C and 6.42g (1.25eq) of triphenylphosphine to 100mL of anhydrous acetonitrile, then add 2.84mL (1.25eq) of anhydrous carbon tetrachloride, and stir overnight at room temperature;

[0049] (2) After the reaction is complete, if a product is precipitated, wash the bottle with cold acetonitrile solution, filter and collect the product, and then purify the filtrate by silica gel column chromatography using petroleum ether as the eluent. Collect the eluent, remove the solvent by vacuum evaporation, and combine the obtained product with the filtered product to obtain compound A.

[0050] Wherein, the structural formula of compound C is shown in formula c-1, and the structural formula of compound A is shown in formula a-1:

[0051]

[0052] The reaction equation for preparing compound A, which has the structural formula as shown in formula a-1, is as follows:

[0053]

[0054] The preparation method of compound C, whose structural formula is shown in formula c-1, is as follows:

[0055] 5 mL of compound E was added to tetrahydrofuran, followed by 14 mL (2 eq) of triethylamine to obtain a mixed solution. The mixture was stirred in an ice-water bath for 10 min. Then, 10 mL of 10.24 g (1.1 eq) of compound D dissolved in tetrahydrofuran was added dropwise to the mixture while maintaining the ice-water bath conditions. After the addition was complete, the mixture was allowed to cool naturally to room temperature and stirred for 24 h. After the reaction was complete, the mixture was filtered, and the filtrate was collected. The filtrate was then evaporated under reduced pressure to remove the solvent and recrystallized to obtain compound C.

[0056] The structural formula of compound E is shown in formula e, and its name is phenylhydrazine, with CAS number 100-63-0; the structural formula of compound D is shown in formula d-1.

[0057]

[0058] The reaction equation for preparing compound C, whose structural formula is shown in formula c-1, is as follows:

[0059]

[0060] Example 2

[0061] A compound A with the structural formula shown in formula a-2:

[0062]

[0063] The preparation method of compound A with the structural formula shown in formula a-2 described in this embodiment is basically the same as that of compound A with the structural formula shown in formula a-1 in Example 1. The difference is that the structural formula of compound C in this embodiment is shown in formula c-2.

[0064]

[0065] The preparation method of compound C, whose structural formula is shown in formula c-2, is basically the same as that of compound C in Example 1. The difference is that the structural formula of compound D in this example is shown in formula d-2, the substance name is 4-(Diphenylamino)benzoyl chloride, and the CAS number is 25069-85-6.

[0066]

[0067] NMR analysis was performed on compound A (NMR results are shown in the figure). Figure 1 (as shown) 1 ¹H NMR (400MHz, Chloroform-d) δ 7.95 (s, 1H), 7.78–7.73 (m, 2H), 7.28 (tdd, J = 7.3, 3.4, 1.6Hz, 6H), 7.17–7.01 (m, 10H), 6.91 (tt, J = 7.4, 1.2Hz, 1H). These results confirm that the obtained product is the target product.

[0068] NMR analysis was performed on the prepared compound C (NMR results are shown in the figure). Figure 2 (as shown) 1 ¹H NMR (400MHz, Chloroform-d) δ 8.00 (s, 1H), 7.70–7.64 (m, 2H), 7.34–7.26 (m, 4H), 7.24–7.17 (m, 2H), 7.17–7.07 (m, 7H), 7.04–6.86 (m, 5H). These results confirm that the obtained product is the target product.

[0069] Example 3

[0070] A compound A, with the structural formula shown in formula a-3, is named 4-(1,1-Dimethylethyl)-N-phenylbenzenecarbohydrazonoyl chloride and has the CAS number 2102886-44-0.

[0071]

[0072] The preparation method of compound A with the structural formula shown in formula a-3 described in this embodiment is basically the same as that of compound A with the structural formula shown in formula a-1 in Example 1. The difference is that the name of compound C with the structural formula shown in formula c-3 in this embodiment is 4-(1,1-Dimethylethyl)benzoic acid 2-phenylhydrazide, and the CAS number is 1624221-64-2.

[0073]

[0074] The preparation method of compound C, whose structural formula is shown in formula c-3, is basically the same as that of compound C in Example 1. The difference is that the structural formula of compound D in this example is shown in formula d-3, the substance name is 4-tert-Butylbenzoyl chloride, and the CAS number is 1710-98-1.

[0075]

[0076] Example 4

[0077] A compound A, with the structural formula shown in formula a-4, is named 4-(1-Methylethyl)-N-phenylbenzenecarbohydrazonoyl chloride and has the CAS number 25939-07-5.

[0078]

[0079] The preparation method of compound A with the structural formula shown in formula a-4 described in this embodiment is basically the same as that of compound A with the structural formula shown in formula a-1 in Example 1. The difference is that the structural formula of compound C in this embodiment is shown in formula c-4, and its name is 4-(1-Methylethyl)benzoic acid 2-phenylhydrazide, and its CAS number is 25957-93-1.

[0080]

[0081] The preparation method of compound C, whose structural formula is shown in formula c-4, is basically the same as that of compound C in Example 1. The difference is that the structural formula of compound D in this example is shown in formula d-4, the substance name is 4-Isopropylbenzoyl chloride, and the CAS number is 21900-62-9.

[0082]

[0083] Example 5

[0084] A benzotriazine diradical compound, the structural formula of which is shown in Formula 1-1:

[0085]

[0086] The specific steps for preparing the above-mentioned benzotriazine diradical compounds are as follows:

[0087] S1: Compound B (0.3 g, 1.896 mmol) and compound A (1.55 g, 3 eq) were added to 50 mL of anhydrous tetrahydrofuran to obtain a mixed solution. 1.8 mL of triethylamine was added to the mixed solution, and the mixture was refluxed at 85 °C for 24 h. After the reaction was completed, the reaction solution was cooled to room temperature and filtered. The filtrate was collected and the solvent was removed by vacuum evaporation to obtain the intermediate product.

[0088] Compound B, as shown in formula b, is named naphthalene-2,6-diamine with CAS number 2243-67-6. Compound A is the compound prepared in Example 1 with the structural formula shown in formula a-1.

[0089]

[0090] S2: The intermediate product (1 eq) was dissolved in anhydrous dichloromethane (20 mL), and a large amount of ethanol (80 mL) was added. Then, 1,8-diazabicyclo[5.4.0]undec-7-ene (2 eq) was added, and the mixture was stirred with air. After the reaction was complete, the mixture was filtered, and the filter cake was washed with ethyl acetate to purify it, yielding the target product compound.

[0091] The specific overall reaction equation is as follows:

[0092]

[0093] The benzotriazine diradical compounds prepared in this embodiment were analyzed by mass spectrometry, and the results are as follows: Figure 3 As shown, the C1 of HRMS(ESI+):[MH]+ was analyzed by mass spectrometry. 40 H 34 N8 2· The calculated value is 626.2906, and the obtained value is 626.4110. The above results confirm that the obtained product is the target product.

[0094] Example 6

[0095] A benzotriazine diradical compound, the structural formula of which is shown in Formula 1-2:

[0096]

[0097] The preparation method of the benzotriazine free radical compound described in this embodiment is basically the same as that in Example 5, except that in step S1, the compound A is the compound A with the structural formula shown in Formula a-2 prepared in Example 2 (the amount of compound A remains unchanged).

[0098] The benzotriazine diradical compounds prepared in this embodiment were analyzed by mass spectrometry, and the results are as follows: Figure 4 As shown, the C1 of HRMS(ESI+):[MH]+ was analyzed by mass spectrometry. 60 H 42 N8 2· The calculated value is 874.3532, and the obtained value is 874.6923. The above results confirm that the obtained product is the target product.

[0099] Example 7

[0100] A benzotriazine diradical compound, the structural formula of which is shown in Formulas 1-3:

[0101]

[0102] The preparation method of the benzotriazine diradical compound described in this embodiment is basically the same as that in Example 5, except that in step S1, the compound A is the compound A with the structural formula shown in Formula a-3 prepared in Example 3 (the amount of compound A remains unchanged).

[0103] The benzotriazine diradical compounds prepared in this embodiment were analyzed by mass spectrometry, and the results are as follows: Figure 5 As shown, mass spectrometry analysis of HRMS (ESI+): CH of [MH]+. 44 H 30 N6 2· The calculated value is 652.3314, and the obtained value is 652.5016. The above results confirm that the obtained product is the target product.

[0104] Example 8

[0105] A benzotriazine diradical compound, the structural formula of which is shown in Formulas 1-4:

[0106]

[0107] The preparation method of the benzotriazine diradical compound described in this embodiment is basically the same as that in Example 5, except that in step S1, the compound A is the compound A with the structural formula shown in Formula a-4 prepared in Example 4 (the amount of compound A remains unchanged).

[0108] The benzotriazine diradical compounds prepared in this embodiment were analyzed by mass spectrometry, and the results are as follows: Figure 6 As shown, mass spectrometry analysis of HRMS (ESI+): CH of [MH]+. 42 H 36 N6 2· The calculated value is 624.3001, and the obtained value is 624.4411. The above results confirm that the obtained product is the target product.

[0109] Example 9: Product Characterization and Performance Testing

[0110] The benzotriazine diradical compounds prepared in Examples 5-8 were named NDMA-D, NDAB-D, NtBu-D, and NiPr-D, respectively, and their performance was characterized.

[0111] (1) Ultraviolet-absorption spectroscopy characterization

[0112] The four benzotriazine diradical compounds prepared in Examples 5-8 of this invention were subjected to ultraviolet-absorption spectroscopy measurements. The obtained data were normalized one by one, and the results are as follows: Figure 7 As shown.

[0113] from Figure 7 As can be seen, all four benzotriazine diradical compounds exhibit a strong absorption peak in the ultraviolet wavelength range (600-1000 nm), corresponding to the π→π* transition in the aromatic ring, respectively. Due to the influence of substituents, the maximum absorption wavelengths differ. Based on the initial absorption wavelengths in the ultraviolet absorption spectra of the four benzotriazine diradical compounds, the optical band gap E of the four compounds can be calculated. g opt The values ​​are 1.33, 1.33, 1.31 and 1.31 eV, respectively.

[0114] The above results show that the spectra obtained from the four compounds prepared in this invention conform to the typical optical absorption characteristics of the Blatter diradical, further proving the accuracy of the molecular structure of the obtained products.

[0115] (2) Thermogravimetric analysis (TGA)

[0116] The thermal properties of the four benzotriazine diradical compounds (NDMA-D, NDAB-D, NtBu-D, and NiPr-D) prepared in this invention were tested by thermogravimetric analysis (TGA) under a nitrogen atmosphere. The results are as follows: Figure 8 As shown, all the diradical compounds exhibited good thermal stability, with thermal decomposition temperatures (5% weight loss temperatures) of 324℃, 301℃, 329℃, and 318℃, respectively. This indicates that the four benzotriazine diradical compounds prepared in this invention can withstand thermal degradation in the light-absorbing layer of a solar interface evaporator.

[0117] (3) Cyclic Voltmeter-Ammeter Test

[0118] Cyclic voltammetry tests were performed on the four benzotriazine radical compounds prepared in this invention: anhydrous dichloromethane was used as solvent, 0.1M Bu4NPF6 was used as supporting electrolyte, Ag / AgCl was used as reference electrode, glassy carbon was used as working electrode, platinum wire was used as auxiliary electrode, and the scan rate was 100mV / s.

[0119] Cyclic voltammetry diagrams of the four compounds are shown below. Figure 9 As shown, the measured ferrocene level is 0.49 eV. The HOMO and LUMO energy levels are calculated using the following formula:

[0120]

[0121] Figure 9 This invention reveals that the four benzotriazine diradical compounds prepared in this invention all exhibit reversible redox behavior. Calculations based on the formula show that the HOMO energy levels of the four compounds are -4.41, -4.50, -4.53, and -4.53 eV; the LUMO energy levels are -3.41, -3.42, -3.41, and -3.43 eV, respectively. Their energy level differences are 1.00, 1.08, 1.12, and 1.10 eV, respectively. The energy level difference determines the wavelength range of light that the material can absorb. If the energy level difference is too large, most visible and near-infrared light cannot be utilized, leading to low photothermal conversion efficiency. If the energy level difference is too small, although the material can absorb more photons, these photons have low energy, resulting in relatively little heat generated when converted into thermal energy through nonradiative relaxation after electronic transitions. Therefore, the four benzotriazine diradical compounds prepared in this invention all have energy level differences that are essentially matched to the solar spectrum, laying the foundation for their excellent performance in the photothermal field.

[0122] (4) Photothermal performance test

[0123] At room temperature, different optical power densities (0.2–1.0 W·cm⁻¹) were first used. -2 The photothermal properties of the four benzotriazine diradical compounds prepared in this invention were tested by irradiating their solid molecular surfaces with an 808 nm laser. The laser beams were then used to test their photothermal properties. -2 The irradiation process was simulated for 10 cycles of heating and cooling, and the results were as follows: Figure 10 As shown, the four benzotriazine diradical compounds prepared in this invention all possess highly efficient photothermal conversion capabilities and exhibit good photostability after 10 cycles with no change in temperature. Therefore, the four benzotriazine diradical compounds prepared in this invention can achieve excellent results in the light-absorbing layer of solar interfacial evaporators.

[0124] (5) Magnetic characterization (ESR characterization)

[0125] One mg of each of the four benzotriazine diradical compounds prepared in this invention was added to a corresponding volume of dichloromethane to prepare a 0.001 M solution. The ESR signals of the resulting solution and the solid powders of the four benzotriazine diradical compounds were then measured. The results are as follows: Figure 11 As shown in the figure, the four benzotriazine diradical compounds prepared in this invention are all magnetic at room temperature, proving their diradical properties. The presence of diradicals suppresses radiative transitions and enhances non-radiative transitions, thereby achieving good photothermal effects.

[0126] Example 10: Preparation of the light-absorbing layer of a solar interface evaporator

[0127] This embodiment prepares a light-absorbing layer for a solar interface evaporator, which is made by loading a benzotriazine diradical compound onto PU foam using solution evaporation technology. Its structure is as follows: Figure 12 As shown. The preparation steps of the light-absorbing layer of the solar interface evaporator are as follows:

[0128] (1) Dissolve 30 mg of benzotriazine diradical compound in 3 mL of organic solvent dichloromethane to prepare a solution;

[0129] (2) Pour the solution into a 5mL beaker and add a piece of PU foam cut to the same diameter as the inner diameter of the beaker (diameter 1.5cm, thickness 0.5cm) to completely impregnate it;

[0130] (3) Allow the solvent to evaporate completely at room temperature;

[0131] (4) Make several large holes in the obtained PU foam loaded with benzotriazine diradical compounds to obtain the light absorption layer of the solar interface evaporator.

[0132] Example 11: Performance Testing of the Light Absorbing Layer in a Solar Interfacial Evaporator

[0133] (1) Photothermal properties

[0134] The temperature response of the light-absorbing layer of a PU foam solar interface evaporator loaded with NDMA-D benzotriazine diradical compound prepared in Example 5 under simulated solar radiation (0.1 W cm⁻²) was systematically monitored using a high-precision thermal infrared camera. The results are as follows: Figure 13 As shown, the light absorption layer of the solar interface evaporator reaches an equilibrium temperature of 118°C in a very short time (25 seconds), demonstrating excellent photothermal conversion capabilities. When placed on water, it still reaches an average temperature of 96°C under solar radiation (0.1W cm⁻²), proving its superior water evaporation capacity.

[0135] (2) Water evaporation efficiency

[0136] By analyzing the weight loss of water recorded by a balance and an infrared thermal imager over one hour, as well as the temperature at the interface between the light-absorbing layer and the water in the solar interface evaporator, we calculated the water evaporation efficiency of the prepared solar interface evaporator's light-absorbing layer to be as high as 98.52%, with an evaporation rate of 1.389 kg m⁻² h⁻¹. Compared to similar NMeO-D benzotriazine diradical compounds with methoxy substituents in previous work, the benzotriazine diradical compound with dimethylamino substituents prepared in Example 5 showed a certain improvement in solar water evaporation efficiency, such as... Figure 14 As shown. This is because benzotriazine diradical compounds with dimethylamino substituents have better photothermal conversion capabilities and stronger absorption of near-infrared light.

[0137] In summary, the benzotriazine diradical small organic molecule compounds prepared in this invention possess good thermal stability and excellent photothermal conversion capabilities, making them suitable for application in the light-absorbing layer of solar interfacial evaporators. This demonstrates the broad research prospects of benzotriazine diradical molecules in photothermal fields such as solar water evaporation.

[0138] The above embodiments are intended to illustrate the essential content of the present invention, but are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of protection of the present invention.

Claims

1. A benzotriazine diradical compound characterized in that, The structural formula is shown as Formula 1: Wherein, R is selected from any one of dimethylamino, diphenylamino, tert-butyl or isopropyl.

2. Process for the preparation of the benzotriazine diradical compounds according to claim 1, characterized in that, The method comprises the following steps: S1: Compound A and compound B are mixed uniformly in tetrahydrofuran, then triethylamine is added, and the mixture is heated to reflux at 85-90°C for 24-48 hours to separate an intermediate product; S2: The intermediate product obtained in step S1 is dissolved in dichloromethane, then ethanol is added, and then 1,8-diazabicyclo[5.4.0]undec-7-ene is added while air is bubbled to stir the reaction, after the reaction is completed, the mixture is filtered, and the filter cake is washed and purified with ethyl acetate to obtain a benzotriazine biradical compound shown as Formula 1; The structural formula of the compound A is selected from any one of Formula a-1, a-2, a-3, a-4; The structural formula of the compound B is shown as Formula b:

3. The method of claim 2, wherein, In step S1, the molar ratio of compound A to compound B is (3-4):1, and the molar ratio of triethylamine to compound A is (1-3):

1.

4. The production method according to claim 3, characterized by, In step S2, the molar ratio of 1,8-diazabicyclo[5.4.0]undec-7-ene to compound A is 1:(1-2).

5. The preparation method according to claim 3, characterized in that, After the reaction in step S1 is completed, the reaction solution is cooled to room temperature, filtered, and the filtrate is collected; the filtrate is subjected to rotary evaporation under reduced pressure to remove the solvent to obtain the intermediate product.

6. The preparation method according to claim 2, characterized in that, The compound A is prepared by the following method: Compound C and triphenylphosphine are added to acetonitrile, then carbon tetrachloride is added, and the mixture is stirred at room temperature; after the reaction is completed, the mixture is filtered, and the filtrate is separated and purified to obtain compound A; wherein the structural formula of the compound C is selected from any one of Formula c-1, c-2, c-3, c-4: The molar ratio of the compound C to triphenylphosphine is 1:(1-2), and the molar ratio of the carbon tetrachloride to the compound C is (1-2):

1.

7. The preparation method according to claim 6, characterized in that, The compound C is obtained by amidation reaction of compound D and compound E; wherein the structural formula of the compound D is selected from any one of Formula d-1, d-2, d-3, d-4, and the structural formula of the compound E is shown as Formula e:

8. Use of the benzotriazine biradical compound of claim 1 in the preparation of a light absorption layer of a solar interfacial evaporator.

9. Use according to claim 8, characterized in that, The light absorption layer of the solar interfacial evaporator is prepared by loading the benzotriazine biradical compound on a PU foam by a solution evaporation technology.

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