Synthesis of titanium-oxo macrocyles and their catalytic properties for oxidative desulfurization.

Two macrocyclic titanium-oxo clusters, namely, [Ti(μ-O)(μ-O)(OCHCHO)(OCHCHOH)(BTA)]·44HO (BTA = butyrate) and [Ti(μ-O)(μ-O)(OCHCHO)(OCHCHOH)(DMBTA)(HDMBTA)]·24HO (DMBTA = 2,2-dimethylbutyrate) were synthesized and structurally characterized. The framework of the Ti-oxo macrocycle was cyclically fixed by the double-deprotonated ethylene glycolate ligands, which exhibit an inner cavity of about 1.2 × 1.2 nm. The catalytic properties of the Ti-oxo macrocycles towards the oxidative desulfurization (ODS) reaction were investigated. The structure-dependent catalytic properties towards oxidative desulfurization were observed for the Ti-oxo macrocycles functionalized with the different carboxylate ligands.