Syntheses, Characterizations And Properties Of Polyoxometalates Modified By Organic Ligands

Four polyoxometalates complexes were successfully synthesized based on the classic type polyoxometalate building blocks, by exploiting appropriate transition metal cations and organic ligands. These complexes have been investigated by CHN,ICP-AES,IR,UV,TG-DSC and X-ray diffractometer analyses and the study on the composition of the compounds, structure and properties were carried out. And the probe of the synthesis conditions and influence factors of synthesis were carried out.1. A new polyoxometalates compound have been synthesized based on the phosphomolybdic acid building blocks by in-situ reaction of salicylaldehyde thiosemicarbazone:[(CH3)2NH2]3[PMo12O40] (1)Compound lwas synthesized by in-situ generation of dimethylamine from salicylaldehyde thiosemicarbazone precursor and effect on H3PMo12O40·xH2O. A one-dimensional chain structure between [PMo12O40]3- units was constituted by hydrogen bonding. Two-dimensional layer structure was constituted by hydrogen bonding base on protonized dimethylamine among the 1D chain. Electrochemical research showed that compound (1) have two steps oxidation and reduction process. Synthetic compounds have good antibacterial properties for e. coli.2. A one-dimensional chain structure compound [(CH3)2NH2]3[PW12O40] (2) which have similar molecular structure to compound 1 was synthesized by Keggin type phosphotungstic acid and in-situ reaction of salicylaldehyde thiosemicarbazone under the condition of 95% ethanol solution. Compound molecules were constituted by hydrogen bonding, and stable two-dimensional supramolecular system was formed. Electrochemical research showed that compound (2) have two steps oxidation and reduction process. Synthetic compounds have good antibacterial properties for e. coli.3. Two organic ligand modified polyoxometallates were synthesized by build unit of coordination compound Zn/salicylaldehyde thiosemicarbazone:{[Zn(C8H9N3OS)(C8H10OS)][PW12O40]}·3H2O (3){[Zn(C8H9N3OS)(C8H10OS)][PMo12O40]}·3H2O (4)Discussed the electrochemical properties and antibacterial properties of compound (3) and compound (4). Experimental results showed that the compounds anions have Keggin type structure. Each [PM12O40]3-(M=W, Mo) structure units and [Zn(C8H9N3OS) (C8H10N3OS)]3+units bonding together through the end oxygen or bridge oxygen of MO6 octahedron, and then constituted organic ligand modified polyoxometallates. Synthetic compounds have good antibacterial properties for e. coli.