Six-coordinate monooxo molybdenum(VI) complexes with N-4-diethylaminosalicylidene-N′-4-nitrobenzoyl hydrazine and catechol ligands: preparation and spectroscopic properties

Preparation and spectroscopic characterization are reported for monooxo molybdenum(VI) complexes, MoO(cat)L, where L2− = dianion of N-4-diethylaminosalicylidene-N′-4-nitrobenzoyl hydrazine and cat2− = catecholate (Cat2−), 4-methylcatecholate (Mecat2−), 3,5-di-tert-butylcatecholate (DTBcat2−), or 4-nitrocatecholate (NO2cat2−). The compounds were prepared by replacement of an oxo group on MoO2L with a catechol. The MoO(cat)L complexes exhibit a Modouble bond; length as m-dashO stretching vibration (νModouble bond; length as m-dashO) at 935–938 cm−1 and a series of five absorptions in the UV–Vis region including a long wave-length band at 655–658 nm which is attributed to cat → Mo charge transfer. The 1H and 13C NMR data are reported and found to be consistent with the formation of monomeric MoO(cat)L compounds.