The five-co-ordinate stereochemistry of dichloro(pyridine-2-aldehyde 2-pyridylhydrazone)cobalt(II)

Abstract

A single-crystal X-ray analysis of Co(paphy)Cl₂ is reported. The complex crystallises as green, monoclinic needles: space group P2₁/c; a= 8·72, b= 11·93, c= 14·32 Å, β= 119·1°, Z= 4. A least-squares refinement of positional and anisotropic vibrational parameters of all 18 atoms has allowed the R factor for 1257 Weissenberg intensities to converge at 8·9%. The complex consists of monomeric molecules with a five-co-ordinate stereo-chemistry for which a square pyramidal description is preferred. Isomorphism with Co(paphy)Br₂ and with halogeno-2,2′,2″-terpyridyl complexes of Mn, Co, Ni, Cu, and Zn indicates that these compounds should be similarly described.