Crystal Structure and Vibrational Behaviour of Tetraaqua-di(nicotinamide)M(II)-Saccharinates, with M(II) = Co, Ni, Zn

The crystal structures of [M(nic)₂ (H2O)₄](sac)₂ (nic = nocotinamide; sac = saccharinate anion) with M = Co(II), Ni(II) and Zn(II), have been determined at 116 K by single-crystal X-ray diffractometry. The compounds crystallize in the triclinic space group P1 with Z = 1, and the M(II) cations present a slightly distorted MN₂O₄ octahedral environment, with equatorially coordinated water molecules and axially pyridine N-bound nicotinamide ligands. The saccharinate anions act as counteranions, and are not part of the first coordination sphere. Some comparisons with related structures have been made and the most important features of their IR spectra discussed.