X-ray and DFT studies of a mono- and binuclear copper(II) ionic compound containing a Schiff base

Abstract

In the structure oftrans-bis(ethanol-κO)tetrakis(1H-imidazole-κN3)copper(II) bis[μ-N-(2-oxidobenzylidene)-D,L-glutamato]-κ4O1,N,O2′:O2′;κ4O2′:O1,N,O2′-bis[(1H-imidazole-κN3)cuprate(II)], [Cu(C3H4N2)4(C2H6O)2][Cu2(C15H14N3O5)2], both ions are located on centres of inversion. The cation is mononuclear, showing a distorted octahedral coordination, while the anion is a binuclear centrosymmetric dimer with a square-pyramidal copper(II) coordination. An extensive three-dimensional hydrogen-bonding network is formed between the ions. According to B3LYP/6–31G* calculations, the two equivalent components of the anion are in doublet states (spin density located mostly on CuIIions) and are coupled as a triplet, with only marginal preference over an open-shell singlet.