Bis(3,5-dimethylpyrazol-1-yl)acetate bound to titania and complexed to molybdenum dioxido as a bidentate N,N′-ligand. Direct comparison with a bipyridyl analog in a photocatalytic arylalkane oxidation by O2

摘要

Bis(3,5-dimethylpyrazol-1-yl)acetate, well known as a tridentate N,N,O ligand, was bound to MoO2Cl2 in a bidentate N,N manner by anchoring covalently, at first, the ligand onto a titanium oxide surface, followed by its complexation with the molybdenum dioxo entity. It was fully characterized by 13CPMAS NMR and FT-IR spectroscopy. The tethered complex was directly compared with an analogous bipyridyl species in the catalytic ethylbenzene oxidation by O2 at room temperature, atmospheric pressure, and under visible light. The bis(pyrazol-1-yl) catalyst exhibited a significant initial higher oxygen atom transfer (OAT) capability, well in accord with its electron donating property. It was, unfortunately, hampered by a premature leaching phenomenon, totally absent in the comparable bipyridyl system.