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

Two macrocyclic titanium-oxo clusters, namely, [Ti₃₂(μ₃-O)₈(μ₂-O)₈(OCH₂CH₂O)₃₂(OCH₂CH₂OH)₁₆(BTA)₁₆]·44H₂O (BTA = butyrate) and [Ti₃₂(μ₃-O)₈(μ₂-O)₈(OCH₂CH₂O)₃₂(OCH₂CH₂OH)₁₆(DMBTA)₁₆(HDMBTA)₂]·24H₂O (DMBTA = 2,2-dimethylbutyrate) were synthesized and structurally characterized. The framework of the Ti₃₂-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 Ti₃₂-oxo macrocycles towards the oxidative desulfurization (ODS) reaction were investigated. The structure-dependent catalytic properties towards oxidative desulfurization were observed for the Ti₃₂-oxo macrocycles functionalized with the different carboxylate ligands.