Solution Structures and Spectra of VO(II)‐Serine‐Phenanthroline Ternary System

ESR spectra of VO(II)‐serine(Ser)‐phen system in binary solvent glycol/water (V/ V = 1:1) solution at various acidities (pH= 1‐14) have been observed at low temperature. It was found that in different pH ranges different structural complexes were formed. According to Johnson's rule and IR, their possible structures were suggested. The bonding parameters of complexes were calculated from ESR parameters. It can be seen that the or values of complexes decrease following the increasing of an N donor replacing the O donor of water on the equatorial plane in the complexes. This means that the covalent bonding between vanadium and ligands increases as amino and phen ligands replace water ligands. The crystal field parameters were calculated by using electronic spectral data. The coordination law was discussed. It was obtained that the coordination reactivity of phen is much stronger than that of Ser.