A 'Butterfly'-shaped Water Tetramer in a Cu4 Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum Chemical Study

A potentially tetradentate NOOO donor hydrazone ligand, LH2 (condensation product of benzhydrazide with O-vanillin) generates a tetranuclear CuII complex [Cu4(L)4]·4H2O (1), whose void spaces are occupied by water tetramers presenting a ‘butterfly’ conformation with the highest dihedral angle reported to date, as revealed by its X-ray crystal structure. 1 has also been characterized using various spectroscopic techniques, including IR, UV-vis, and elemental analysis. Variable temperature magnetic susceptibility measurements reveal the presence of moderate antiferromagnetic intra-tetramer coupling between the four CuII centres connected through simple oxo groups of the hydrazone ligand with…