Metal complexes of 5-acetyl-2,2′-pyridylthiophene aroylhydrazones. Crystal structure of a cobalt(II) derivative

The new potentially tetradentate aroylhydrazone ligands, Hbitp and Hsitp, produced by condensation of 5-acetyl-2,2′- pyridylthiophene with benzoyl- and salicyloylhydrazine, respectively, have been reacted with several metal(II) acetates. Deprotonation at the amide nitrogen occurs and neutral complexes of the type [M(bitp)2L2] and [M(sitp)2L2] are obtained, where L is a solvent molecule. An X-ray crystal structure determination carried out on [Co(bitp)2(dmso)2] (I) revealed that these ligands behave as bidentate through the (O)CNN hydrazide moiety, assuming the Z configuration around the CN hydrazone bond. The coordination environment is distorted octahedral, the solvent molecules occupying the axial positions. The crystal structure of the Ligand Hbitp (II) has also been determined for comparison.