Synthesis And Electrochemical Properties Of {Mo₂??-S?₂O₂}-based Cyclic Oxothiomolybdenum Cluster Complexes Incorporating Polycarboxylates Ligands

The chemistry of sulfur-containing polyoxometalates(POTMs)have received much attention not only for their diverse structural chemistry,high electron storage capacities but also duo to the potential applications in electrocatalytic redox-based systems.Especially,the cyclic polyoxothiometalates demonstrated a novel class of cyclic host-gest structure,in which,the shape and size of the rings was defined by the coordinated gest.The desigin of different ring-size,robust,efficient electrocatalytic cyclic polyoxothiometalates has become a focus in the chemistry of polyoxometalates.The object of this thesis is the synthesis of a new cyclic polyoxothiometalates based on the self-condensation of {Mo2(?-S)2O2} oxothiocations around anionic templates.In the system,five different structural polycarboxylate ligands:3,5-Pyridinedicarboxylic acid(H2PyD),3,4-Pyridinedicarboxylic acid(H2CinC),1,4-Naphthalenedi carboxylic acid(H2NapH),Oxalic acid(H2Ox),2,5-Thiophenedicarboxylic acid(H2ThiP)were employed as template ligands,respectively.And then five new cyclic oxothiomolybdate have been obtained:(Me4N)4-xKx[Mo20O20S20(OH)20(C7H6O4N)2]·xH2O(1);noted:[Mono-(PyD)2]4-;K2-xCsx[Mo12O12(?-S)i2(?-OH)12(H2O)5(Ci2H6O4)]·xH2O(2);noted:[Mo12-NapH]2-;(Me4N)4-xKx[(Mo8O8(?-S)8(?-OH)8)2(C2O4)2]·xH2O(3);noted:[(Mo8)2-(Ox)2]4-;K2-xCsx[Mo10O10(?-S)10(?-OH)10(H2O)5(C6H2O4S)]·xH2O(4);noted:[Moio-ThiP]2-;(Me4N)4-xKx[Mo10O10(?-S)10(?-OH)10(H2O)5(C7H3O4N)2]·xH2O(5);noted:[Mo10-(CinC)2]4-.Finally,their structure was unambiguously characterized in the solid state by FT-IR spectroscopy,Thermogravimetric analysis(TG),UV-visible spectroscopy,X-ray single-crystal diffraction,X-ray power diffraction(XRD).Additionally,the elecrochemical properties of compound 1-5 and elecrocatalytic performance of compound 1-3 at room temperature have been investigated.