Electron spin resonance and optical absorption spectral studies on some manganese(II) complexes with 2,2′-bipyridyl, 4,4′-bipyridyl and their dioxides

Abstract

Coordination compounds formed by the interaction of manganese(II) chloride, thiocyanate, acetate and sulphate with 2,2′-bipyridyl (2,2′-Bipy), 4,4′-bipyridyl (4,4′-Bipy) and their dioxides have been characterized by electron spin resonance and optical absorption spectral studies in solid and solution states to determine the spin-Hamiltonian constant for manganese(II), metal-ligand bond parameters and the tentative environments around manganese(II). The metal-ligand σ,-bond in the compounds studied herein in formamide solution is found to be moderately covalent. The compounds seem to have an essentially axial symmetry with g-value close to 2.0. The magnetic moments, electronic and photoacoustic spectra of these complexes are also recorded and interpreted in the solid state.