[CoI2(C6H4N3CH2CO2C4H2SCO2CH2C6H4N3)], a coordination polymer containing the thiophene-2,5-di(carboxylatomethylenebenzotriazole) bridging ligand: synthesis, structure, redox properties

The title complex was obtained by reacting CoI2 with thiophene-2,5-di(carboxylatomethylenebenzotriazole) in dichloromethane. The single-crystal X-ray structure analysis of the green material reveals a polymeric chain of CoI2 units, tetrahedrally coordinated and connected by the 3-nitrogen atoms of the two benzotriazole groups of the multifunctional ligand. The paramagnetic cobalt(II) polymer can be oxidised by hexachloroethane to give the corresponding cationic cobalt(III) complex [CoI2(C6H4N3CH2CO2C4H2SCO2CH2C6H4N3)(H2O)2]+ which is diamagnetic and precipitates as the green–yellow chloride salt.