Vibrational spectra of anhydrous metal pyridine nitrates

Abstract

Vibrational spectroscopy has been used to investigate the nature of the metal–ligand environment of Cu(py)_n(NO₃)₂ where n= 2, 3, and 4 and M(py)₃(NO₃)₂ where M = Co, Ni, and Zn. Extensive use of isotopic substitution and related techniques were made to assign the low frequency i.r. spectra (350–75 cm^–1). It has been observed for the Cu(py)_n(NO₃)₂ system, that as the covalency of the nitrate bonding increases, the copper–oxygen stretching vibration shifts to higher energy, while the copper–nitrogen stretching vibration moves to lower energy.