Copper(II)-disulphide interaction in copper complexes containing salicylaldimine and pyridylaldimine ligands: synthesis,spectra and redox behaviour

Summary Copper(II) complexes of Schiff base ligands formed by the condensation of cystamine (cys) or 2,2-diaminodiphenyl-disulphide (ddds) with salicylaldehyde (sal) or pyridine-2-carboxaldehyde (pal), and also their C=N reduced analogues, have been isolated and characterised. The e.p.r. spectra of the complexes reveal a d _x ²-y² ground state and exhibit low A and g values. The spectral results suggest equatorial coordination of disulphide in a square-based geometry. The -delocalisation, unsaturation and flexibility in the ligands affect the ligand field, charge transfer and e.p.r. spectral parameters as well as the redox behaviour.