Solid-State Coordinative Behavior of a New Asymmetrical Bis-hydrazone Ligand Containing Two Different Binding Pockets

The potentially multidentate (O2N–NO) trianionic bis­(bencylhydrazone) derived from 4-hydroxyisophthaldehyde (H3L) ligand has been synthesized and characterized. The coordinative behavior of the ligand has been explored toward different MII salts (M = Co, Ni, Zn, and Cu), and four complexes, of general formula [M­(HL)]·solv (2·solv = molecules of water, dmf, or dmso), have been isolated and characterized. Furthermore, the species [M­(H2L)2]·solv (M = Co, 1a·solv; M = Ni, 1b·solv; solv = molecules of water and/or dmf), where the ligand is monodeprotonated and tridentate, has also been detected. The structures of H3L, four solvates of {[Cu­(HL)]·solv}n (2c·solv), 1a·5H2O, and 1b·H2O·3dmf were determined by single-crystal X-ray diffraction. The effect of weak interactions on the crystal packing has also been analyzed. The thermal stability and the structural dynamics of the 2c·solv systems have also been investigated.