Synthesis, X-ray structure and spectroscopic investigation of an eight-coordinate cadmium(II) complex

Abstract

Reaction of 4-methylimidazole-5-carbaldehyde (L) with cadmium(II) nitrate (M : L = 1 : 2; EtOH) yields a novel eight-coordinate mononuclear complex, [CdL2(NO3)2]. X-ray structural analysis indicates that the Cd(II) ion possesses what can be described as a double coordination sphere. The inner coordination sphere is pseudo-tetrahedral and consists of four atoms, N(1), N(11), O(21) and O(42), with bond lengths ranging from 2.252(2) to 2.371(2) Å. The second or outer coordination sphere is composed of four oxygen donors, O(7), O(17), O(22) and O(41), with Cd–O distances of 2.543(2) to 2.756(2) Å. The atoms of the external coordination sphere form pyramids with the pseudo-tetrahedral faces of the inner coordination sphere. IR and Raman spectra confirm the stabilization of the Nπ–H isomer of the ligand.