Pseudohalide-induced structural variations in hydrazone-based metal complexes: Syntheses, electrochemical studies and structural aspects

摘要

The effects of pseudohalides on the modes of binding of a hydrazone ligand are investigated and we report here four new hydrazone complexes [Co(L)(2)] center dot ClO4 (1), [Co(L)(2)](2)[Co(SCN)(4)] (2), [Mn(L)(2)] (3) and [Mn(N-3)(2) (LH)(2)] center dot H2O (4) [where LH = condensation product of pyridine-2-carboxaldehyde and benzhydrazide]. The hydrazone ligand is quite diverse in its chelating ability and can act as a neutral or mononegative ligand and as a bidentate or tridentate unit. In this paper, we report structures showing different denticities of the ligand having different charges. The complexes are characterized by IR, UV-Vis spectroscopy and cyclic voltammetric studies and the structures are conclusively established by single crystal X-ray diffraction study. Of the complexes, 1 and 3 are purely metal hydrazone complexes whereas 2 and 4 incorporate coordinated pseudohalides in their crystal structures, and 4 shows different coordination modes of the hydrazone ligand.