The Study Of Preparation, Characterization And Photo-thermal Properties Of A Series Of Multi-nuclear Mixed-valent Cu(Ⅰ/Ⅱ) Clusters Constructing By Chloride

Mixed-valence copper(Ⅰ/Ⅱ)clusters have excellent full spectrum absorption properties,thus attracting researchers’ attention as a potential photothermal conversion material.Due to the formation of mixed-valence copper(Ⅰ/Ⅱ)clusters involving the coexistence of monovalent and divalent copper ions,as well as the stability of monovalent copper ions,rational design and controllable preparation still face challenges.In the early stage,the research group successfully prepared a series of pentanuclear mixedvalence copper clusters(CuⅡCuⅠ4)through triazole/tetrazole ligands with uneven charge density distribution.On this basis,a series of chlorine involved multi-core mixed-valence copper clusters(Ⅰ/Ⅱ)were prepared by directly or indirectly introducing chlorine ions into the reaction system.Their molecular formula,valence state,and structure were confirmed through X-ray single crystal diffraction analysis,mass spectrometry,and other characterization methods.Their light absorption performance was studied through solid-state ultraviolet absorption spectroscopy,and their photothermal conversion performance was evaluated through photothermal conversion temperature rise experiments.The main research content of this paper is as follows:(1)Three polynuclear mixed-valence copper(Ⅰ/Ⅱ)clusters involving chloride ions were successfully constructed by regulating the types of phosphine/azole ligands,reaction solvents,and introduction methods of chloride ions.The molecular formulas were{CuⅡ[CuⅠ(PCy3)]4(BTA)4Cl2}·5DMF(Ⅰ),{(CuⅡ)3[CuⅠ(P(PhMe)3)]6(TTA)10Cl2}·3DMF(Ⅱ),{(CuⅡ)3[CuⅠ(PPh2Py)]6(BTA)8Cl4}·6DMF(Ⅲ)(Note:PCy3=tricyclohexylphosphine,P(PhMe)3=triphenylmethylphosphine,PPh2Py=diphenylpyridylphosphine,BTA=benzotriazole,TTA=methyl-1H-benzotriazole),respectively.Single crystal structure analysis shows that the three clusters contain different numbers of chloride ions,different divalent copper contents,and different nuclear numbers.Related research has developed a new method for preparing novel multi core mixedvalence copper(Ⅰ/Ⅱ)clusters,enriching the types of multi core mixed-valence copper(Ⅰ/Ⅱ)clusters.(2)Their light absorption performance and thermal stability were compared and studied through solid-state UV absorption spectroscopy and thermogravimetric analysis.The results show that compared with the series of mixed-valence copper(Ⅰ/Ⅱ)clusters without chloride ions,the introduction of chloride ions has less effect on the light absorption capacity of the mixed-valence copper(Ⅰ/Ⅱ)clusters.But to a certain extent,the thermal stability of the mixed-valence copper(Ⅰ/Ⅱ)clusters is reduced.The increase of the number of chloride ions in the mixed-valence copper(Ⅰ/Ⅱ)cluster has little effect on its light absorption capacity,but the increase of divalent copper content can improve its light absorption capacity.The related studies provide an experimental basis for modifying and modifying mixed-valence copper(Ⅰ/Ⅱ)clusters from the atomic level.(3)The photothermal conversion performance of a series of multi-core mixed-valence copper(Ⅰ/Ⅱ)clusters was compared and evaluated by photothermal conversion and heating experiments.The results showed that the photothermal equilibrium temperature of cluster Ⅱ and Ⅲ was as high as 50.8℃ and 49.2℃,which was significantly higher than that of cluster Ⅰ(46.3℃).Therefore,the photoabsorption performance of mixed-valence copper(Ⅰ/Ⅱ)clusters is consistent with that of mixed-valence copper(Ⅰ/Ⅱ)clusters,and the mixed-valence copper(Ⅰ/Ⅱ)clusters with high relative content of divalent copper have good photothermal conversion performance,while the introduction of chloride ions has little effect on their photothermal conversion performance.Related research provides new ideas for the molecular design and directional construction of new high-efficiency photothermal absorption materials and highperformance photothermal conversion materials.