Coordination behaviour of nicotinamide: an infrared spectroscopic study

Abstract

A series of Hofmann-type complexes containing two nicotinamide(nia) molecules attached to transition metal (II) (M) tetracyanonickelate frame with the formula: M(nia) 2Ni(CN) 4 (where M=Mn, Co, Ni, Cu or Cd) have been synthesised for the first time. Metal (II) halide complexes of nicotinamide complexes of the type [M(nia) 2X 2 (M=Cd, Ni, Cu, Hg; X=Cl, Br) and Ni(nia) 4Br 2 nia=nicotinamide] have also synthesised. The FTIR spectra are reported in the 4000–400 cm −1 region. Vibrational assignments are given for all the observed bands. The analysis of the vibrational spectra indicates that there are some structure–spectra correlations. A pronounced change was observed in the N–H stretching frequencies of the NH 2 group. It is proposed that the amide NH 2 group influence by the intramolecular hydrogen bond in the complexes. The coordination effect on the nicotinamide modes is analysed.