Synthesis and Characterization of Complexes of Co(II) and Mn(II) with 1-(2′ -Hydroxysenzyl)-2-(2′-Hmroxyphfnyl)-Bexzimidazole

Abstract

A series of low spin octahedral complexes of Co(II) and high spin octahedral complexes of Mn(II) have been synthesized and studied by IR, electronic, vibrational spectral methods and also by physico-chemical methods such as magnetic thermal and conductance studies. The absorption bands appearing in the region greater than 16000 cm⁻¹ were attributed to n →σ∗, σ, and σπ∗ transitions within the ligand molecules and metal → ligand charge transfer transitions. The ligand field bands were not assigned for the present complexes, because all the ligand field bands were obscured by σπ∗ transitions and charge transfer bands of high intensity. The Co(II) complexes were assumed to be low spin octahedral, since a significant absorption band was detected in the range round 18000 cm⁻¹. A Strong IR band appearing around 1480 cm⁻¹ was assigned to the C = N stretching mode and it is observed that this band was shifted to lower frequencies upon coordination. A magnetic moment lower than 1.9 BM for all cobalt (II) complexes is consistent with low spin octehedral geometry. Whereas the magnetic moment of 5 BM for all Mn(II) complexes corresponds to high spin octahedral values. Conductance studies show the existence of non-ionic species.