A highly novel dinickel complex: A hydrogen-bonded anti-skew carboxylate bridge and a 2D supramolecular structure

Reaction of the tridentate Schiff base ligands obtained from 2,4-dihydroxybenzaldehyde and either l-isoleucine or l-tert-leucine with Ni(NO3)2 in methanol/water solution in the presence of base afforded dinickel complexes. The crystal structure of the product derived from l-tert-leucine has been determined by X-ray crystallography. The octahedrally coordinated two Ni centers were found to be bridged by a single carboxylate group in an extremely unusual non-planar fashion. A 2D supramolecular structure, constructed by infinite hydrogen-bonded complex sheets parallel to the ab-plane of the unit cell, arises from intermolecular O–H⋯O hydrogen bonds.