Crystal structure of a sodium complex, bis-[NN′-ethylenebis(salicylideneiminato)copper(II)]perchloratosodium–p-xylene

Abstract

A purple compound is formed between sodium perchlorate and two molecules of the copper complex of the Schiff's base NN′-ethylenebis(salicylideneimine)(salen); the p-xylene solvate has been subjected to three-dimensional X-ray crystal structure analysis. The structure was solved by Patterson and Fourier methods and refined by full-matrix least squares to R 0·070 for 1083 diffractometer observations. Z= 4 in a monoclinic unit cell having a= 24·44 ± 0·01, b= 11·283 ± 0·006, c= 14·766 ± 0·004 Å, β= 101·22 ± 0·03°, space group C2/c. The sodium ion lies on a two-fold axis and is co-ordinated approximately octahedrally by oxygen atoms; two, at 2·55 Å, from a perchlorate ion also situated on the two-fold axis, and four from the two salen molecules, so that the sodium ion shares these oxygen atoms with a copper atom, Na–O 2·36, Cu–O 1·90 Å. The copper is four-co-ordinated, Cu–N 1·94 Å, and the salen ligand as a whole is nearly planar apart from the carbon atoms of the ethylene-diamine entity which correspond to a gauche conformation about the C–C bond. Axial contacts to copper are to an oxygen in the other salen ligand (3·43 Å) and to a copper atom in another molecule (3·42 Å). The p-xylene molecule occupies a centre of symmetry and fills a space in a loosely packed structure; its nearest carbon atom neighbour is at 3·93 Å.