Synthesis and Characterization of Cobalt(III) Octahedral Complexes with Flexible Salpn Schiff Base in Solution. Structural Dependence of the Complexes on the Nature of Schiff Base and Axial Ligands

Abstract

For a long time tetradentate Schiff base complexes of transition metal ions have attracted many researchers interest in the field of coordination chemistry.1-5 Co(III) complexes of Schiff base are an important class of coordination compound not only because of them being interesting B 12 models and oxygen carriers but also due to their interesting magnetic properties, spectroscopic characteristics and the interaction of metal-to-ligand bonds. 4-9Many studies initially focus on simple Schiff base ligand such as salophen, salen and acacen (n = 2) Scheme 1 1,4,5,10,11 but interest quickly shift to more intricate species which have extra functional groups, side chains and more methylene groups in the amine backbone.12-15 A number of structural studies on the effect of the number of CH 2 groups between the two imine moieties in VO

Experimental and Computational Study of the Thermodynamic Properties of Trivalent Cobalt Schiff Base Complexes with Cyclic Amines

“…Disappearance of these signals due to -OH and -NH protons in the spectra of the cobalt(III) complexes indicates the deprotonation of these groups which supports the coordination of ligand through oxygen and nitrogen atoms with cobalt atom. 21 A singlet peak at 2.19-2.36 ppm with three proton integration has been assigned to the methyl group of the acetyl moiety. The proton chemical shifts for the coordinated PBu 3 appear at 0.71-2.06 ppm and are in agreement with the previous results observed for metal complexes of phosphine as axial ligand.…”

Synthesis, Physiochemical, Thermal, Catalytic and Electrical Studies of Mn(III) VO(IV), MoO2(VI) and UO2(VI) Complexes with Unsymmetrical Schiff Base Ligand

“…The strong band observed at 1635 cm -1 due to (C=N) stretch in ligand spectrum has been shifted to lower frequency by ca. 20-40 cm -1 upon coordination 21,22 . The Mn(III) complex show two bands at 1656 and 1449 cm -1 corresponding to  asym (COO -) and  sym COO -he magnitude of the separation  COO-between the frequencies of  asym (COO -) and  sym COO - in Mn(III) complex is much greater ( COO-= 207 cm -1 ) than the ionic value ( COO-= 158 cm -1 ).…”