Copper(II) complexes of tetradentate N2S2 donor sets: Synthesis, crystal structure characterization and reactivity

Two mononuclear and one dinuclear copper(II) complexes, containing neutral tetradentate NSSN type ligands, of formulation [CuII(L1)Cl]ClO4 (1), [CuII(L2)Cl]ClO4 (2) and [CuII2(L3)2Cl2](ClO4)2 (3) were synthesized and isolated in pure form [where L1 = 1,2-bis(2-pyridylmethylthio)ethane, L2 = 1,3-bis(2-pyridylmethylthio)propane and L3 = 1,4-bis(2-pyridylmethylthio)butane]. All these green colored copper(II) complexes were characterized by physicochemical and spectroscopic methods. The dinuclear copper(II) complex 3 changed to a colorless dinuclear copper(I) species of formula [CuI2(L3)2](ClO4)2,0.5H2O (4) in dimethylformamide even in the presence of air at ambient temperature, while complexes 1 and 2 showed no change under similar conditions. The solid-state structures of complexes 1, 2 and 4 were established by X-ray crystallography. The geometry about the copper in complexes 1 and 2 is trigonal bipyramidal whereas the coordination environment about the copper(I) in dinuclear complex 4 is distorted tetrahedral.

Three copper(II) complexes of NSSN type ligands, two mononuclear [CuII(L1)Cl]ClO4 (1), [CuII(L2)Cl]ClO4(2) and one binuclear [CuII2(L3)2Cl2](ClO4)2 (3) were isolated in pure form. The dinuclear copper(II) complex 3 changed to a colorless dinuclear copper(I) species of formula [CuI2(L3)2](ClO4)2 (4) in dimethylformamide even in the presence of air at ambient temperature, while complexes 1 and 2 showed no change under similar conditions.Figure optionsDownload as PowerPoint slide