A Vibrational Spectroscopic Study of Hofmann Type Complexes of 3 and 4 Methyl Pyridines

Abstract

The FT-IR and Raman spectra of eight new Hofmann-type complexes of 3- and 4-methylpyridine, ML2Ni(CN)4 (M = Mn, Fe, Co or Zn; L = 3- or 4-methylpyridine) are reported. The structure consists of corrugated polymeric layers of [MNi(CN)4]∞ with methylpyridine molecules bound directly to the metal (M). For a given ligand (3-Mepy or 4-Mepy) the effects of metalligand bond formation on the ligand modes are examined and the metal sensitivity sequence of the ligand frequencies is found to be Mn < Fe < Co < Zn. The metalligand bond strengths of the methyl derivatives of pyridine in which the substituents are in different positions have also been compared and are found to increase in the order 3-Mepy < 4-Mepy for a given transition metal. The effective magnetic moments of the complexes are given.