Synthesis and characterization of copper(I) and copper (II) complexes with1,5-bis (benzimidazol-2-yl)-3-thiapentane

Complexes with formula [Cu(BBES)X-2](. n)H2O have been synthesized where BE ES is a tridentate ligand containing bis-benzimidazolyl as pendant coordina ting group and X is an exogenous anionic ligand (X = HCOO-, CH3COO-, Cl-, B r, NO3-). Solution EPR d(x2-y2) orbital. Cyclic spectroscopy on these compl exes reveals that the ground state in these copper (II) complexes comprises d(x2-y2) voltammetric studies reveal that E-1/2 for Cu(II)/Cu(I) couple sh ifts cathodically with HCOO- as the anionic ligand, implying that binding o f this anion stabilizes the Cu (II) state whereas E-1/2, data for NCS indic ates that this anion destabilizes Cu(II) state. Copper (I) complex has also been synthesised in the presence of hydroquinone which shows a well-resolv ed NMR spectrum in the range 0-10 ppm.