Spectral and structural studies of copper(II) complexes of thiosemicarbazones derived from salicylaldehyde and containing ring incorporated at N(4)-position

Mononuclear and binuclear copper(II) complexes (1-8) with two ONS donor thiosemicarbazone ligands {salicylaldehyde 3-hexamethyleneiminyl thiosemicarbazone H2L1] and salicylaldehyde 3-tetramethyleneiminyl thiosemicarbazone H2L2]} have been prepared and physico-chemically characterized. IR, electronic and EPR spectra of the complexes have been obtained. The thiosemicarbazones bind to metal as dianionic ONS donor ligands in all the complexes except in Cu(HL1)2] (2) and Cu(HL2)2] (6). In compounds 2 and 6 the ligands are coordinated as monoanionic HL- ones. The magnetic susceptibility measurements indicate that all the complexes are paramagnetic. In complex (CuL1)2] (1), the magnetic moment value is lower than the expected spin only value. In all the complexes g(||)>g( perpendicular)>2.0023 and G values within the range 2.5-3.5 are consistent with dx2-y2 ground state. The complexes were given the formula as (CuL1)2] (1); Cu(HL1)2] (2); CuL1bpy] (3); CuL1phen] (4); CuL1gamma-pic].2H2O (5); Cu(HL2)2] (6); CuL2py].3H2O (7); CuL2bipy] (8). The structure of the compound 8 have been solved by single crystal X-ray crystallography and was found to be distorted square pyramid around copper(II) ion.