Hydrazone-Based Ligand with Pyrrolidine Donor and Its Molybdenum(VI) Complex: Synthesis, Structure, and Reactivity

Abstract

The Schiff-base condensation of salicylaldehyde and 4-aminobutanehydrazide hydrochloride leads to the hydrazone-based ligand H2salhyab containing an amino side chain. The reaction of H2salhyab ⋅ HCl with bis(acetylacetonato)dioxidomolybdenum leads to the formation of [MoO2(salhycab)(MeOH)] (H2salhycab=2-((pyrrolidine-2-ylidenehydrazineylidene)methyl)phenol), whereby the amino side chain reacted with the hydrazide carbonyl group to form a cyclic amidine with a pyrrolidine ring leading a new type of tridentate hydrazone ligand with [NNO] donor set. X-ray crystallography revealed the additional coordination of a methanol molecule at the molybdenum(VI) center which leads to the formation of hydrogen-bonded dimers of the neutral complex in the crystal structure. The complex [MoO2(salhycab)(MeOH)] was found to be an efficient catalyst for the peroxidic oxidation of phenyl methyl sulfide.