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

Two macrocyclic titanium-oxo clusters, namely, [Ti-32(mu(3)-O)(8)(mu(2)-O)(8)(OCH2CH2O)(32)(OCH2CH2OH)(16)(BTA)(16)]center dot 44H(2)O (BTA = butyrate) and [Ti-32(mu(3)-O)(8)(mu(2)-O)(8)(OCH2CH2O)(32)(OCH2CH2OH)(16)(DMBTA)(16)(HDMBTA)(2)]center dot 24H(2)O (DMBTA = 2,2-dimethylbutyrate) were synthesized and structurally characterized. The framework of the Ti-32-oxo macrocycle was cyclically fixed by the double-deprotonated ethylene glycolate ligands, which exhibit an inner cavity of about 1.2 x 1.2 nm. The catalytic properties of the Ti-32-oxo macrocycles towards the oxidative desulfurization (ODS) reaction were investigated. The structure-dependent catalytic properties towards oxidative desulfurization were observed for the Ti-32-oxo macrocycles functionalized with the different carboxylate ligands.