Synthesis, electronic, photoacoustic and electron spin resonance investigations on some tetrathiocyanate binuclear mixed-metal complexes

Abstract

Complexes of the type M 1M 2(SCN) 4 xL[M 1 = Ni(II); M 2 = Cd(II) and Hg(II) and L = pyridine, morpholine, dioxan, benzo(f)quinoline, 2,2′-bipyridine, 2,2′-bipyridine N, N′-dioxide, isonicotinic acid hydrazide and 1,10-phenanthroline: x = 2 or 4] have been synthesized and characterized by chemical analysis, magnetic susceptibility, infrared, electronic and photoacoustic (PAS) spectra as well as electron spin resonance (ESR) spectral studies in the solid and solution state. The different coordination sites have been investigated in these ligands towards metal coordination and the behaviour of thiocyanate anions studied. Electron spin resonance spectral data for copper complexes show the distorted octahedral stereochemistry around copper(II) in these complexes. The parameters such as g ∥, g ⊥, A ∥, A ⊥, < g>, < A> and α 2 calculated for the copper complexes from their ESR spectra indicate the presence of unpaired electron in d x 2- y 2 or d z 2 orbitals. The photoacoustic and electronic spectra of these complexes were studied in the solid state to see the nature of thiocyanate and overall symmetry of the complexes. The results on electronic and photoacoustic spectral studies are in good agreement with ESR data.