On the spectroscopic evidence of the out-of-plane displacement of cobalt in phthalocyaninato cobalt(II) and in its adducts with base molecules

Abstract

The vibrational analysis in the far-i.r. region, and the electronic analysis, in the visible region of frequencies, have been performed on the adducts of phthalocyaninato cobalt(II), [Co(pc)], with base molecules. The results of the vibrational analysis show that relation exists between the bending frequency δ[N(pc)CoN(pc)] and the amplitude of angle N(pc)ĈoN(pc); specifically the bending frequency is representative of the displacement of cobalt out of the phthalocyaninato plane. These results lead to conclude that: the change of polymorphous form of [Co(pc)] (α→β), the electronic structure and bond properties of the mono and biadducts of [Co(pc)] with bases, and the change of spin state of cobalt in [Co(pc)(3 Mepyridine)] are all depending on the out-of-plane position of cobalt. The results of the electronic analysis show that the electron transfer from the d π metal orbitals to the π* orbitals of the phthalocyaninato does not vary in the series of the [Co(pc)] adducts, while the differences found in the back-donation are relatable to back-donation from the cobalt to the axial ligand.