Synthesis and spectroscopic studies of new bis(N-1-hydroxy-2, 6-di-tert-butylphenyl-salicylideneaminato)cobalt(II) complexes and their oxidation withPbO2

A series of new bis(N-( 1-OH-2,6-di-tert-butylphenyl)salicylaldiminato)coba lt(II) complexes possessing one or two HO- and CH3O- substituents on the sa licylaldehyde moiety were prepared, and their spectroscopic properties as w ell as oxidation with PbO2 were examined. ESR data indicate that oxidation of the complexes produces stable phenoxyl radicals. All phenoxyl radicals h ave similar g-values and hyperfine coupling constants, which were less infl uenced by the substituents and coordination. The experimental observations indicate that some Co(L-x)(2) radical ligand complexes are ligand-localized and there is not much contribution From the metal d-orbitals to the values of the g-factors. We were also able to observe satellite peaks from the C- 13 nuclei in the aromatic ring. ESR spectra of some complexes during the ti me showed the partial conversion of primary radicals to secondary paramagne tic species exhibiting interaction of the radical center with Co-59(I= 7/2) and N-14 nuclei.