Abstract

M. T. H. Tarafder¹*, S. K. Tan¹, K. H. Su¹ and N. Saravanan², G. Mariotto²,

Some dioxygen complexes of cobalt(II), zinc(II), antimony(V), tantalum(V) and niobium(V) of the compositions [M(O)2LCl(H2O)n], [M(O2)L(H2O)n], [M(O2)L2(H2O)n]Cl, [M’(O2)2LCl] and [M’(O2)2L’Cl], [M=Co(II), Zn(II); n=0 or 1; M’=Sb(V), Nb(V) and Ta(V); L = 1,2-phenylenediamine, 2-aminopyridine, O-phenanthroline, 1,4-diaminobutane diethylenetriamine, L'= pyridine-N-oxide, triphenylphospine] have been synthesized and characterized by elemental analyses, conductivity measurements, IR and Raman spectral studies. Comparison of the IR and Raman spectra indicate that the dioxygens are bonded in an end-on, superoxo-type manner, in the cobalt and zinc complexes, (1), (2) and (5), giving n1(O=O) stretching modes at 1125-1150cm-1, while they are side-on peroxo species in some other zinc, antimony, niobium and tantalum complexes, (3), (4), (6)-(14), with n1(O=O) bands at 816-868 cm-1. The effect of dp-pp bonding in the M-O2- moiety in the superoxo complexes makes them stronger oxidants than the peroxo analogues toward triphenylphosphine.

Organodioxygen complexes; superoxo complexes and peroxo species

[ View HTML Full Text]