Synthesis,modification And Catalytic Applications Of Silver (Cadmium) Chalcogenolate Clusters

d¹⁰Metal chalcogenolate clusters usually are of diverse structures and tunable optical properties,demonstrating great potential in fluorescence,photocatalyses and photovoltaics.Several silver thiolate clusters and heterometallic silver-cadmium chalcogenolate clusters were synthesized via solution method in this thesis,The clusters were modified by pyridine ligands and thus their structural stability was increased.Furthermore,their catalytic performances were investigated for a range of organic reactions.Reactions of([ⁱPr SAg]_nwith CF₃SO₃Ag formed two silver thiolate cluster-based polymers[Ag₁₀（ⁱPr S）₈（CF₃SO₃）₂（Py）₄]_n（1）and[Ag₁₀（ⁱPr S）₈（CF₃SO₃）₂（2,3-Me₂Py）₂]_n（2）in the presence of pyridine（Py）and 2,3-dimethylpyridine（2,3-Me₂Py）,respectively.Their structures were determined by single X-ray diffraction analysis and the results revealed that the structures of silver thiolate cluster-based polymers 1 and 2showed a one-dimensional chain structure.The analysis of their powder X-ray diffraction（PXRD）patterns indicated that the two polymers were relatively stable in air.The high stability of the polymeric clusters can be attributed to the fact that the surface-coordinated pyridine molecules protected the core structure of the silver thiolate cluster by avoiding the reaction with oxygen and moisture in the air.In addition,the two polymers showed high catalytic activity in the reaction between CO₂and propargylamine,which surpassed those of many silver-based catalysts.Reactions of 4-pyridinecarboxaldehyde（4-pyal）with the supertetrahedral shaped clusters[Cd₆Ag₄（SPh）₁₆（DMF）₄]and[Cd₆Ag₄（SPh）₁₆（DMA_C）₄]formed two new clusters[Cd₆Ag₄（SPh）₁₆（DMAc）₂（4-pyal）₂]（4）and[Cd₆Ag₄（SPh）₁₆（DMF）₂（4-pyal）₂]（5）,during which 4-pyal replaced two terminal solvent molecules in the original clusters.On the other hand,the coordination between Cd₆Ag₄（SPh）₁₆（DMF）₄and1,2-bis（4-pyridinyl）ethane（bpe）with a rigid and conjugated structure formed a new coordination polymer（CP）[Cd₆Ag₄（SPh）₁₆（DMF）（H₂O）（bpe）]_n（6）,where the cluster acted as a secondary building unit while the bpe served as a bridging linker.The structures of the obtained clusters and the CP were determined by single X-ray diffraction analysis.Due to the charge transfer between the pyridine ligands and the clusters,the modified clusters and the CP showed broader UV-vis absorption in comparison with the original cluster.In addition,the CP 6 was employed as a heterogeneous catalyst for the photocatalytic degradation of organic dye（Rhodamine B）in aqueous solution.Its catalytic mechanism was also investigated.The results indicated that the CP 6 showed relative high photocatalytic activity and good recyclability.