Synthesis, characterization, crystal structure and density functional theory (DFT) calculations of dioxomolybdenum (VI) complexes of an ONS donor ligand derived from benzoylacetone and S-benzyl dithiocarbazate

A few dioxomolybdenum complexes of the type MoO2L and MoO2L·B of a new diprotic tridentate ONS chelating ligand, H2L, have been synthesized with the aim to examine their potential to behave as models for the active site of an oxidoreductase molybdoenzyme like xanthineoxidase. The MoO2L complex produces MoO2L·B on treatment with neutral monodentate Lewis bases such as γ-picoline, 2-methylimidazole or 1-allylimidazole, utilizing the vacant sixth coordination site. They have been characterized by spectroscopic and electrochemical techniques. The complexes MoO2L (1), MoO2L(γ-pic) (2) and MoO2L(1-allyl imz) (4) were structurally characterized by single crystal X-ray diffraction. The complex MoVIO2L exhibits oxotransfer to PPh3 in acetonitrile medium leading to the formation of MoIVOL, which is reoxidized to MoVIO2L on treatment with DMSO or pyridine N-oxide. DFT calculations on the ligand and complexes 1, 2 and 4 were also carried out.

Graphical abstractA number of mononuclear dioxomolybdenum complexes of the type MoVIO2L and MoVIO2L·B (where B is a monodentate Lewis base) of a tridentate chelating ligand are isolated in the solid state. Crystal structures and DFT calculations of the dioxomolybdenum complexes MoVIO2L, MoVIO2L(γ-pic) and MoVIO2L(1-allyl imz) have been reported.Figure optionsDownload full-size imageDownload as PowerPoint slide