Synthesis method and application of silver cluster protected by tert-butyl thiacalix [4] arene

Abstract

The invention belongs to the technical field of nano materials, and provides a synthesis method and application of a p-tert-butyl thiacalix [4] arene protected silver cluster, and the synthesis method comprises synthesis of a p-methyl phenyl sulfide silver precursor, preparation of a mixture, synthesis of a compound 1, synthesis of a compound 2 and contrast of the mixture of the compound 1 and the compound 2. The synthesis of the p-methyl phenyl sulfide silver precursor comprises AgNO3, acetonitrile, p-MePhSH, Et3N and an ethanol solution, and the mixture comprises (p-MePhSAg) n, H4TC4A, K2Cr2O7, DMF (Dimethyl Formamide) and PhCOOAg. Aggregation of generated Ag (0) atoms is regulated by regulating and controlling reduction kinetics of DMF to realize regulation and control of a silver core, a compound 1 and a compound 2 are synthesized, the compound 1 shows good photo-thermal conversion performance as a photo-thermal conversion agent, and the compound 2 shows good detoxification capacity as a catalytic degradation agent of nitro aromatic chemical substances.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and in particular relates to a synthesis method of a silver cluster protected by tert-butylthiacalix[4]arene and an application thereof. Background Art

[0002] The controllable synthesis of metallic nanoclusters with atomic precision is challenging due to the complex assembly process and the difficulty in obtaining high-quality crystals for single-crystal X-ray diffraction structural analysis. 44 To Ag 374 Although significant progress has been made in the crystallization and determination of the precise structure of silver clusters, trial and error is still the most commonly used method in the synthesis of silver clusters. Therefore, it is very important to master the method of regulating the growth of silver clusters, which is mainly related to the kinetic process affected by multiple factors such as temperature, reactant concentration, and solvent.

[0003] Some typical methods are known, such as heat-induced isomer reversible conversion and ligand-regulated synthesis of metal nanoclusters of different sizes and shapes. However, due to the fast growth of the metal core, the importance of the metal core to cluster assembly is difficult to express in these regulation methods. The metal core represents the embryonic state during the growth of the cluster, which not only provides some early structural models for understanding the assembly mechanism of the cluster, but also has a decisive influence on the molecular structure and electronic structure of the cluster.

[0004] With NaBH 4 Compared with the fast reduction process, N,N-dimethylformamide (DMF) as a mild reducing agent has been widely used in the synthesis of metal nanoparticles and metal colloid materials. In the process of DMF participating in the redox to obtain silver clusters, the reaction mechanism is: Me 2 NCOH + 2Ag(I) + H 2 O → 2Ag(O) + Me 2 NCOOH + 2H + , reacting to form N,N-dimethylaminoformic acid and Ag(O), the latter of which can aggregate to form silver nuclei.

[0005] For the silver clusters currently obtained by reduction with weak reducing agents such as TBA 8 [Ag 6 (γ-H 2 S W 10 O 36 ) 2 ]、[Ag 6 @(CrO 4 ) 8 @Ag 52 ]、[Ag 10 @(Mo 7 O 26 )2 @Ag 70 ] and [Ag 6 @(MoO 4 ) 7 @Ag 56 ], the reactants, solvents, temperatures and experimental conditions used in the synthesis of the silver clusters in these examples are quite different, and it can only prove that DMF has reducing ability in the silver cluster assembly process. However, it was found through experiments that different silver cluster compounds can be synthesized by regulating the DMF reduction kinetics to adjust the silver cluster assembly process, and the produced compounds have their own advantages in performance and practical application. Summary of the invention

[0006] The present invention aims at solving the technical problems existing in the method for synthesizing silver cluster nanomaterials, and proposes a method for synthesizing silver clusters protected by tert-butylthiacalix[4]arene, wherein the aggregation of generated Ag(O) atoms is regulated by regulating the reduction kinetics of DMF to achieve the regulation of the silver core. The synthetic chemical formula is [(CrO 4 ) 4 @Ag 46 (C 4 OH 44 O 4 S 4 ) 5 (p-MePhS) 16 (C 3 H 7 NO) 5 ]·6(C 3 H 7 NO) and the compound 1 with the chemical formula [(CrO 4 ) 2 @Ag 34 (C 4 OH 44 O 4 S 4 ) 4 (p-MePhS) 10 (PhCOO) 4 (C 3 H 7 NO) 7 (H 2 O)]·3(C 3 H 7 NO), and proposed the application of compound 1 as a photothermal conversion agent and the application of compound 2 as a catalytic degradation agent.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is a method for synthesizing a silver cluster protected by tert-butylthiacalix[4]arene provided by the present invention, wherein the silver cluster comprises compound 1 and compound 2 and the chemical formulas thereof are:

[0008] [(CrO 4 ) 4 @Ag 46 (C 4 OH 44 O 4 S 4 ) 5 (p-MePhS) 16 (C 3 H 7 NO) 5 ]·6(C 3 H 7 NO);

[0009] [(CrO 4 ) 2 @Ag 34 (C 4 OH 44 O 4 S 4 ) 4 (p-MePhS) 10 (PhCOO) 4 (C 3 H 7 NO) 7 (H 2 O)]·3(C 3 H 7 NO);

[0010] The synthesis method of compound 1 and compound 2 comprises the following steps:

[0011] S1. Synthesis of methylphenylsulfide silver precursor: AgNO 3 Dissolved in acetonitrile, then added p-MePhSH and Et 3 N ethanol solution, keep stirring for 5 hours in the dark, filter, wash with ethanol and ether in turn, dry, and synthesize (p-MePhSAg) n ;

[0012] S2. Preparation of the mixture: Take (p-MePhSAg) synthesized in step S1 n Same as H 4 TC4A, K 2 Cr 2 O 7 Dispersed together in DMF, stirred at 800 rpm for 3 h at room temperature, PhCOOAg was added, and stirred at the same speed for another 3 h;

[0013] S3, prepare 3 parts of the mixture according to steps S1 and S2;

[0014] S4, synthesis of compound 1: take a portion of the mixture of step S3, seal it in a stainless steel autoclave containing a polytetrafluoroethylene liner, and heat it at 65 ° C for 33 hours; after cooling to room temperature, black rod-shaped crystals of compound 1 are obtained;

[0015] S5. Synthesis of compound 2: Take a portion of the mixture from step S3, centrifuge the red solution, and slowly evaporate it at room temperature in the dark for 1-2 weeks to obtain compound 2 in the form of red block crystals;

[0016] S6. Control experiment of a mixture of compound 1 and compound 2: Take a portion of the mixture of step S3, perform a thermal reaction at 50° C., filter the solution after the thermal reaction, and slowly evaporate to obtain a mixture of compound 1 and compound 2.

[0017] Preferably, in step S1, AgNO 3 , for p-MePhSH and Et 3 The millimole ratio of the three N is 5:5:6, the milligram mass ratio of the three is 125:93:125, the volume of acetonitrile is 75 ml, and the volume of ethanol is 100 ml.

[0018] Preferably, in step S2, (p-MePhSAg) n , H 4 TC 4 Ace and King 2 Cr 2 O 7 The millimole ratio of the three is 1:3:5, the milligram mass ratio of the three is 114:108:73, the volume of DMF is 1.5 mL, and the molar number and mass of PhCOOAg are 0.1 mmol and 22.9 mg, respectively.

[0019] Preferably, the compound 1 is a 46-nuclear two-electron non-superatomic cluster silver cluster.

[0020] Preferably, the compound 2 has two CrO 4 2- The anion template is a 34-core silver cluster, two of which are CrO 4 2- Only as anion template, μ 8 -κ 3 :κ 3 :κ 1 :κ 1The coordination mode plays a role in supporting the silver shell, with Ag-O distances ranging from 2.302 to 2.561 Å; 5 DMF molecules and 1 H 2 O molecules cover the surface of the silver skeleton through Ag-O interactions.

[0021] An application of a silver cluster protected by tert-butylthiacalix[4]arene, and an application of the compound 1 as a photothermal conversion agent.

[0022] An application of a silver cluster protected by tert-butylthiacalix[4]arene, and an application of the compound 2 as a catalytic degradation agent for nitroaromatic chemicals.

[0023] Compared with the prior art, the advantages and positive effects of the present invention are:

[0024] 1. The present invention provides a method for synthesizing a silver cluster protected by tert-butylthiacalix[4]arene, which uses temperature to control the reduction kinetics of DMF to synthesize two TC4A with different molecular and electronic structures. 4- The protected silver clusters achieve the control of the growth of silver clusters from the embryonic state; Ag 10 8+ Compound 1 with a two-electron structure of the core was isolated at room temperature as a 34-core Ag(I) cluster compound 2. The silver core in the early stage of nucleation is highly active and needs to be passivated by anions or ligands to prevent excessive aggregation; through the synergistic strategy of reduction and passivation, the silver core was captured to promote the understanding of the silver species in the early stage of nucleation and its application on the subsequent growth of silver clusters; the anion plays a dual role of internal passivation of the silver core and external shaping of the silver shell, CrO 4 2- It has multiple coordination sites and flexible coordination modes, and is an ideal anion template; thiacalixarene is a class of multi-dentate macrocyclic compounds, whose coordination sites are composed of phenolic hydroxyl groups and bridging sulfur atoms, and is a good ligand and core passivation group.

[0025] 2. The present invention provides an application of a silver cluster protected by tert-butylthiacalix[4]arene, wherein compound 1 exhibits good photothermal conversion performance as a photothermal conversion agent, and compound 2 exhibits good detoxification ability as a catalytic degradation agent for nitroaromatic chemicals. 10 8+ The inner core represents a completely new embryonic state in the growth process of the silver cluster; since compound 2 has more exposed silver atoms, it is easier for reactants to adsorb on the catalyst surface and exhibits higher catalytic activity than compound 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 is the crystal structure diagram of compound 1;

[0028] Figure 2 is the crystal structure diagram of compound 2;

[0029] Figure 3 The electrospray ionization mass spectrum of compound 2 dissolved in a mixed solvent of dichloromethane and methanol in positive ion mode and the molecular formula schematic diagram of species 1a-1c;

[0030] Figure 4 The electrospray ionization mass spectrum of compound 2 dissolved in a mixed solvent of dichloromethane and methanol in positive ion mode and the molecular formula schematic diagram of species 2a-2h;

[0031] Figure 5 The chloroform solution of compound 1 with different concentrations at 660 nm 0.7 W cm -2 Photothermal conversion diagram under laser irradiation;

[0032] Figure 6 The chloroform solution of compound 2 with different concentrations at 660 nm 0.7 W cm -2 Photothermal conversion diagram under laser irradiation;

[0033] Figure 7 Schematic diagram of the cyclic heating and cooling process of compound 1;

[0034] Figure 8 Schematic diagram of the cyclic heating and cooling process of compound 2;

[0035] Fig. 9 Schematic diagram of UV-visible absorption spectra of chloroform solutions of compound 1 and compound 2 at a concentration of 12.5 µM;

[0036] Fig.10 Schematic diagram of heating and cooling curves of chloroform solution of compound 1 with a concentration of 100 µM under laser irradiation at 660 nm;

[0037] Fig.11 Schematic diagram of heating and cooling curves of chloroform solution of compound 2 with a concentration of 100 µM under laser irradiation at 660 nm;

[0038] Fig.12The catalytic reaction of compounds 1 and 2 with NaBH at 293.15 K 4 Schematic diagram of UV-visible spectrum of reduced p-NP;

[0039] Fig.13 This is the reduction process of p-nitrophenol catalyzed by compound 1;

[0040] Fig.14 This is the reduction process of p-nitrophenol catalyzed by compound 2;

[0041] Fig.15 The catalytic concentration of compound 2 is 1.3×10 -3 The time-dependent reduction process of p-NPs of M;

[0042] Fig.16 The catalytic concentration of compound 2 is 7.2×10 -3 The time-dependent reduction process of p-NPs of M;

[0043] Fig.17 NaBH 4 Schematic diagram of the time-dependent reduction process of p-NP catalyzed by compound 2 at a concentration of 0.176 M;

[0044] Fig.18 For NaBH 4 Schematic diagram of the time-dependent reduction process of p-NP catalyzed by compound 2 at a concentration of 0.264 M;

[0045] Fig.19 Schematic diagram of the effect of p-NP concentration on reduction rate;

[0046] Fig. 20 NaBH 4 Schematic diagram showing the effect of the concentration of compound 2 on the p-NP reduction rate. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear below, they only indicate that the upper, lower, left and right directions are consistent with the accompanying drawings themselves, and do not limit the structure.

[0048] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0049] Examples, such as Figures 1 to 20 As shown, the present invention provides a synthesis method and application of a p-tert-butylthiacalix[4]arene protected silver cluster, wherein the silver cluster comprises compound 1 and compound 2 and the chemical formulas are:

[0050] [(CrO 4 ) 4 @Ag 46 (C 4 OH 44 O 4 S 4 ) 5 (p-MePhS) 16 (C 3 H 7 NO) 5 ]·6(C 3 H 7 NO);

[0051] [(CrO 4 ) 2 @Ag 34 (C 4 OH 44 O 4 S 4 ) 4 (p-MePhS) 10 (PhCOO) 4 (C 3 H 7 NO) 7 (H 2 O)]·3(C 3 H 7 NO);

[0052] The synthesis method of compound 1 and compound 2 comprises the following steps:

[0053] S1. Synthesis of methylphenylsulfide silver precursor: AgNO 3 Dissolved in acetonitrile, then added p-MePhSH and Et 3 N ethanol solution, keep stirring for 5 hours in the dark, filter, wash with ethanol and ether in turn, dry, and synthesize (p-MePhSAg) n Among them, AgNO 3 , for p-MePhSH and Et 3 The millimole ratio of the three is 5:5:6, and the milligram mass ratio of the three is 125:93:125; specifically, AgNO 3 , for p-MePhSH and Et 3The molar numbers of N are 30 mmol, 30 mmol and 36 mmol respectively, the masses of the three are 5 g, 3.72 g and 5 g respectively, the volume of acetonitrile is 75 ml, and the volume of ethanol is 100 ml;

[0054] S2. Preparation of the mixture: Take (p-MePhSAg) synthesized in step S1 n Same as H 4 TC4A, K 2 Cr 2 O 7 The millimole ratio of the three is 1:3:5, and the milligram mass ratio of the three is 114:108:73. Specifically, the molar numbers of the three are 0.05 mmol, 0.015 mmol and 0.025 mmol, respectively, and the masses of the three are 11.4 mg, 10.8 mg and 7.3 mg, respectively. The three are dispersed in 1.5 mL DMF, and after stirring at 800 rpm for 3 hours at room temperature, 0.1 mmol and 22.9 mg of PhCOOAg are added, and stirred at the same speed for another 3 hours;

[0055] S3, prepare 3 parts of the mixture according to steps S1 and S2;

[0056] S4, synthesis of compound 1: take a portion of the mixture of step S3, seal it in a stainless steel autoclave containing a polytetrafluoroethylene liner, and heat it at 65 ° C for 33 hours; after cooling to room temperature, black rod-shaped crystals of compound 1 are obtained;

[0057] S5. Synthesis of compound 2: Take a portion of the mixture from step S3, centrifuge the red solution, and slowly evaporate it at room temperature in the dark for 1-2 weeks to obtain compound 2 in the form of red block crystals;

[0058] S6. Control experiment of a mixture of compound 1 and compound 2: Take a portion of the mixture of step S3, perform a thermal reaction at 50° C., filter the solution after the thermal reaction, and slowly evaporate to obtain a mixture of compound 1 and compound 2.

[0059] Through the comparison of step S6, it can be known that the reduction kinetics of DMF is affected by temperature, and the final synthesis of the mixture in step S3 can be significantly affected at different temperatures.

[0060] The present invention provides a method for synthesizing a silver cluster protected by tert-butylthiacalix[4]arene, which regulates the aggregation of the generated Ag(O) atoms by regulating the reduction kinetics of DMF, including temperature, reactant concentration, solvent and light conditions, to achieve regulation of the silver core, and can synthesize compounds 1 and 2. Specifically, the silver core in the early stage of nucleation has high activity and needs to be passivated by anions or ligands to prevent excessive aggregation; through the synergistic strategy of reduction and passivation, the silver core is captured to promote the understanding of the silver species in the early stage of nucleation and the influence of its application on the subsequent growth of the silver cluster; the anion plays a dual role of internally passivating the silver core and externally shaping the silver shell, CrO4 2- It has multiple coordination sites and flexible coordination modes, and is an ideal anion template; thiacalixarene is a class of multi-dentate macrocyclic compounds, whose coordination sites are composed of phenolic hydroxyl groups and bridging sulfur atoms, and is a good ligand and core passivation group.

[0061] like Figure 1 As shown, about compound 1: Compound 1 crystallizes in the triclinic P-1 space group and consists of 46 silver atoms, 4 CrO 4 2- Anion, 5 TC4A 4- , 16 p-MePhS − and 5 DMF. In detail, the silver skeleton of compound 1 consists of a pyramidal Ag 10 Core and Ag 36 Shell composition. Pyramid-shaped Ag 10 The core is made of Ag 6 The octahedron is composed of silver atoms covering four adjacent triangular faces, while the other four adjacent triangular faces are covered with four CrO 4 2- Anions support the silver shell through Ag-O bonds. 4 CrO 4 2- Anions are expressed in μ 7 -κ 3 :κ 2 :κ 1 :κ 1 , μ 8 -κ 3 :κ 2 :κ 2 :κ 1 :κ 1 and μ 6 -κ 2 :κ 2 :κ 1 :κ 1 Three different coordination modes will Ag 36 Shell and Ag 10The core is connected by Ag-O bonds with a bond length range of 2.201-2.684 Å. 4 2- Anions play a triple role in the construction of compound 1: 1. Passivation of Ag 10 Core; 2. Support Ag 36 Shell; 3. Connect the core and shell layer. 10 In the core, the range of Ag···Ag interaction is 2.729-3.091 Å, with an average value of 2.915 Å, indicating a strong silver-philic interaction. 46 For the skeleton, the Ag···Ag interactions are in the range of 2.729 Å-3.375 Å. 4- The ligands are all bound to the silver atom in the form of Ag 5 @TC4A's modes combine to form μ 5 -κ o 3 :κ o 3 :κ o 3 :κ o 3 :κ s 1 :κ s 1 :κ s 1 :κ s 1 :κ s 1 The distances between Ag-O and Ag-S are in the range of 2.230-2.672 Å and 2.437-2.621 Å, respectively. This multi-dentate multi-site coordination mode enhances the overall stability of compound 1. 4- A DMF molecule is encapsulated in the cavity, with its methyl group pointing into the cavity. 4- The CH···π interaction distance and angle formed are in the range of 2.532-3.113 Å and 135.08-175.03°, respectively. 88 and Ag 18 In the solvent molecule CH 3 CN and CHCl 3 It can also be encapsulated in the cavity of calixarene through CH···π interactions, which shows that calixarene is a powerful platform for displaying rich host-guest chemistry. Host-guest chemistry is also widely used in many aspects, such as the detection of different types of toxic molecules, as a carrier of drugs and dye adsorption. The 16 p-MePhS− ligands adopt two coordination modes: 12 of them are p-MePhS− Using μ 4 The other four use μ 3 The coordination mode of Ag 10 4 p-MePhS in the core − μ 4 The coordination mode of the other 12 p-MePhS − μ 4 and μ 3 The coordination patterns of p-MePhS are arranged alternately on the silver shell. In addition, there are 5 DMF molecules coordinated with the silver atoms through Ag-O interactions, with an average distance of 2.366 Å. − 、TC4A 4- 、PhCOO − The differences in steric hindrance, electronic properties and coordination patterns of DMF and DMF cause them to cover different areas of the silver shell.

[0062] like Figure 3 and Figure 4 As shown, electrospray ionization mass spectrometry has been widely used to determine the chemical composition and charge state of metal nanoclusters. The solution behavior of compound 1 and compound 2 in a mixed solvent of dichloromethane and methanol was determined using electrospray ionization mass spectrometry.

[0063] Compound 1 has a group of peaks in the mass-to-charge ratio range of 3000-9000. By expanding each peak, the isotope distribution characteristic difference between two adjacent peaks is calculated to be 0.5, corresponding to +2 valent species. 1a-1c are respectively assigned to [compound 1- 2p-MePhS − + CH 2 Cl 2 + 3H 2 O] 2+ , [Compound 1 + Ag + -p-MePhS − + H 2 O] 2+ and [compound 1+ Ag + -p-MePhS − +DMF + CH 3 OH + H 2 O] 2+ Therefore, compound 1 is a neutral cluster with a two-electron structure; at the same time, compound 1 has two free electrons in its core, which belongs to the "magic number" of the spherical jellAum model (2, 8, 18, 20, etc.). However, the orbital topology and DOS curve do not show a superatomic S orbital, probably due to the relatively low symmetry of the cluster. Therefore, it is inferred that compound 1 is a two-electron non-superatomic cluster.

[0064] like Figure 2 As shown, about compound 2: there are two CrO 4 2- The anion-templated 34-core silver cluster is composed of 10 p-MePhS − , 4 TC4A 4- , 4 PhCOO − , 7 DMF and 1 H 2 O co-protection. The silver skeleton of compound 2 without peripheral ligands is dumbbell-shaped, which can be regarded as two CrO fused by Ag···Ag interaction. 4 @Ag 17 Cage composition. Two CrO 4 @Ag 17 One of the cages can be rotated 180 degrees around the axis to coincide with the other. The Ag···Ag interaction of compound 2 ranges from 2.845 to 3.360 Å, with an average of 3.130 Å, which is weaker than the Ag···Ag interaction of compound 1 (3.020 Å). Four TC4A 4- The ligands are coordinated with six silver atoms to form Ag 6 @TC4A, forming μ 6 -κ o 4 :κ o 3 :κ o 3 :κ o 3 :κ s 1 :κ s 1 :κ s 1 :κ s 1 :κ s 1 It is worth noting that the four TC4A 4- The ligands are divided into two pairs and arranged on both sides of the silver skeleton. 4- In addition to the ligand, compound 2 was also − 、PhCOO − , DMF and H 2 O protected, they are almost symmetrically distributed on the surface of compound 2. 10 p-MePhS − The ligands were all μ 4 The coordination mode is located in the irregular Ag 4 On the quadrilateral, the Ag-S distance ranges from 2.392 to 2.910 Å. − The ligand exhibits two different coordination modes, two of which are μ4 -κ 2 :κ 2 The coordination mode serves to connect the two CrO 4 @Ag 17 The other two are based on μ 2 -κ 1 :κ 1 The coordination mode is located at CrO 4 @Ag 17 Obviously, the coordination mode of the former should be more stable than that of the latter, which was also confirmed by the subsequent mass spectrometry study. 4 2- Only as anion template, μ 8 -κ 3 :κ 3 :κ 1 :κ 1 The coordination mode plays a role in supporting the silver shell, with Ag-O distances ranging from 2.302 to 2.561 Å. Five DMF molecules and one H 2 O molecules cover the surface of the silver skeleton through Ag-O interactions.

[0065] The present invention provides an application of a p-tert-butylthiacalix[4]arene-protected silver cluster, including the application of compound 1 as a photothermal conversion agent. Compound 1 is a photothermal conversion agent superior to compound 2 and can be used in application scenarios requiring the participation of a photothermal conversion agent.

[0066] like Figures 5 to 11 As shown, Figure 5 From top to bottom, lines a, b, c, and d are green, 100 µM; orange, 50 µM; light purple, 25 µM; and navy, chloroform. Regarding the photothermal response of compound 1 and compound 2: under 660nm laser irradiation, no fluorescence was observed for compound 1 and compound 2, indicating that the radiation transition is very weak, so photothermal conversion becomes the main pathway for energy release. In order to evaluate the photothermal conversion ability of chloroform solutions of compound 1 and compound 2, the power density was 0.7Wcm -2 The photothermal conversion properties of compound 1 were studied under 660 nm laser irradiation. After continuous laser irradiation, the temperature of the compound 1 solution increased rapidly and reached the maximum temperature within 4 minutes. The maximum temperature reached 56.12℃ (ΔT = 36.12℃) at a concentration of 100µM, which is 5.65 times that of compound 2 (ΔT = 6.39℃). The maximum temperature of compound 1 is significantly higher than that of compound 2. This is because compound 1 has a smaller HOMO-LUMO energy gap, resulting in stronger absorption at 660 nm than compound 2. At a power density of 0.7Wcm -2Under 660 nm laser irradiation, the photothermal conversion efficiency η of 100 μM compound 2 in chloroform solution was 48.68% and 10.7%, respectively. 2 Se (22.9%) and CTAB-Ag 2 Compared with Se (20.1%), compound 1 has a higher η and can be used as a good photothermal conversion agent. In addition, the maximum temperature increases with the increase of sample concentration. At each concentration, compound 1 shows a faster heating rate and higher temperature under laser irradiation than compound 2. In addition, they both have good photothermal stability. After 6 rounds of heating and natural cooling, the maximum temperature has almost no change.

[0067] The present invention provides an application of a p-tert-butylthiacalix[4]arene protected silver cluster, and the application of the compound 2 as a catalytic degradation agent for nitroaromatic chemicals. Since compound 2 has more exposed silver atoms, it is easy for reactants to be adsorbed on the catalyst surface, and it exhibits higher catalytic activity than compound 1, and has good application in detoxification.

[0068] Regarding the catalytic activity of compound 1 and compound 2 in reducing nitrophenol: Nitroaromatic chemicals are highly toxic and biodegradable, and can enter the human body through the respiratory tract or skin, causing neurological diseases, anemia and liver damage. However, aminophenol is widely used as a fine organic chemical intermediate, a raw material in the pharmaceutical industry, a dye, a developer and an antioxidant. The present invention uses p-nitrophenol (p-NP) reduction as a model reaction to test the catalytic activity of compound 1 and compound 2.

[0069] Specifically, Figures 12-14 As shown, the reagent conditions [p-NP] = 3.6×10 -3 M; [NaBH 4 ] = 0.088 M. The p-NP solution has characteristic absorption peaks at 322 nm and 400 nm. 4 The addition of NaBH resulted in only one peak at 400 nm, and the color changed from light yellow to bright yellow, which was due to the formation of deprotonated p-NP. After 4 hours of reaction without catalyst, the peak position and absorption intensity did not change significantly, indicating that NaBH 4 p-NP cannot be reduced without a catalyst. Under the catalysis of compound 1 and compound 2, NaBH 4The UV-visible spectrum evolution of reduced p-NP showed that the characteristic absorption peak intensity of p-nitrophenol ion at 400 nm decreased with the increase of the absorption peak intensity of p-aminophenol (p-AP) ion at 297 nm. In addition, the appearance of isosbestic points (281 nm and 313 nm) indicated that p-NP was completely converted into p-AP without the generation of by-products. Moreover, under the catalysis of compound 2, p-NP could be completely reduced to p-AP within 30 minutes, while compound 1 required 3 hours to complete the reduction under the same reaction conditions, indicating that the catalytic activity of compound 2 was higher than that of compound 1, and regulating the structure of metal nanoclusters was of great significance to regulating their catalytic performance.

[0070] Taking compound 2 with higher catalytic activity as an example, by changing the p-NP and NaBH 4 A series of kinetic experiments were conducted to investigate whether the reaction process was concentration-dependent and to further determine the reaction mechanism. 4 concentrations accelerated the completion of the reaction, indicating that the reaction mechanism involves p-NP ions and BH 4- The adsorption on the catalyst surface conforms to the LangmuAr-Hanshelwood (LH) model. The reduction rate of nitrophenol can be calculated using the pseudo-first-order kinetic equation: − = − = kapp; where Ct (At) and C0 (A0) are the concentration at time t and the initial concentration (absorbance) during the p-NP reduction reaction. The kapp of compound 2 was calculated to be 8.93 h −1 , is compound 1 (2.49 h −1 ) is 3.59 times.

[0071] like Fig.15 , 16 As shown in 19, NaBH 4 = 0.088 M; Fig.17 , 18 , as shown in 20, where p-NP = 3.6×10 -3 M. Different concentrations of p-NP or NaBH 4 The kapp further indicated that the catalytic reaction conformed to the LH model.

[0072] To further study the catalytic activity of compounds 1 and 2, we carried out the reduction of o-nitrophenol (o-NP) and m-nitrophenol (m-NP) under the same conditions as the p-NP reduction reaction. The experiments showed that compound 2 has more exposed silver atoms than compound 1, so it has a higher activity in catalyzing the reduction of nitrophenol, and the reduction rates of the three nitrophenol isomers are: p-NP>o-NP>m-NP. This work not only reveals the tunability of DMF reduction kinetics, but also provides new ideas for regulating the assembly process of silver clusters.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for synthesizing a silver cluster protected by tert-butylthiacalix[4]arene, characterized in that: The following steps are involved: S1. Synthesis of p-MePhSAg precursor: AgNO3 was dissolved in acetonitrile, followed by addition of p-MePhSH and Et3N ethanol solution, stirring for 5 hours in the dark, filtered, washed with ethanol and ether in turn, and dried to synthesize (p-MePhSAg). n ; S2. Preparation of the mixture: Take (p-MePhSAg) synthesized in step S1 n Dispersed in DMF together with H4TC4A and K2Cr2O7, stirred at 800 rpm for 3 hours at room temperature, PhCOOAg was added, and stirred at the same speed for another 3 hours; S3, prepare 3 parts of the mixture according to steps S1 and S2; S4. Take a portion of the mixture in step S3, heat react at 50° C., filter the solution after the heat reaction, and slowly evaporate to obtain a mixture of compound 1 and compound 2, wherein the chemical formulas of compound 1 and compound 2 are: [(CrO4)4@Ag 46 (C4OH 44 O4S4)5(p-MePhS) 16 (C3H7NO)5]·6(C3H7NO); [(CrO4)2@Ag 34 (C4OH 44 O4S4)4(p-MePhS) 10 (PhCOO)4(C3H7NO)7(H2O)]·3(C3H7NO)。 2. The method for synthesizing a p-tert-butylthiacalix[4]arene-protected silver cluster according to claim 1, characterized in that: In step S1, the millimole ratio of AgNO3, p-MePhSH and Et3N is 5:5:6, the milligram mass ratio of the three is 125:93:125, the volume of acetonitrile is 75 ml, and the volume of ethanol is 100 ml.

3. The method for synthesizing a p-tert-butylthiacalix[4]arene-protected silver cluster according to claim 2, characterized in that: In step S2, (p-MePhSAg) n The millimole ratio of H4TC4A and K2Cr2O7 is 1:3:5, the milligram mass ratio of the three is 114:108:73, the volume of DMF is 1.5 mL, the molar number and mass of PhCOOAg are 0.1 mmol and 22.9 mg respectively.

4. The method for synthesizing a p-tert-butylthiacalix[4]arene-protected silver cluster according to claim 3, characterized in that: Take a portion of the mixture in step S3, seal it in a stainless steel autoclave with a polytetrafluoroethylene liner, and heat it at 65° C. for 33 hours; after cooling to room temperature, a black rod-shaped crystal compound 1 is obtained, wherein the compound 1 is a 46-nuclear two-electron non-superatomic cluster silver cluster.

5. The method for synthesizing a p-tert-butylthiacalix[4]arene-protected silver cluster according to claim 3, characterized in that: Take a portion of the mixture in step S3, centrifuge the red solution, and slowly evaporate it at room temperature in the dark for 1-2 weeks to obtain compound 2 in the form of red block crystals.

6. The method for synthesizing a p-tert-butylthiacalix[4]arene-protected silver cluster according to claim 5, characterized in that: The compound 2 has two CrO4 2- Anion template of 34-core silver cluster, two of the CrO4 2- Only as anionic template, μ8-κ 3 :κ 3 :κ 1 :κ 1 The coordination mode plays a role in supporting the silver shell, with the Ag-O distance ranging from 2.302-2.561 Å; 5 DMF molecules and 1 H2O molecule cover the surface of the silver skeleton through Ag-O interactions.

7. An application of a silver cluster protected by tert-butylthiacalix[4]arene, characterized in that: Use of the compound 1 described in claim 4 as a photothermal conversion agent.

8. An application of a silver cluster protected by tert-butylthiacalix[4]arene, characterized in that: Use of the compound 2 described in claim 6 as a catalytic degradation agent for nitroaromatic chemicals.

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