8-Hydroxyquinoline functionalized titanium-oxo clusters for visible-light-driven photocatalytic oxidative desulfurization

The 8-hydroxyquinoline functionalized titanium-oxo clusters were synthesized which exhibit favorable catalytic activity for the visible-light-driven photocatalytic oxidative desulfurization (PODS). • The 8-hydroxyquinoline functionalized titanium-oxo clusters were synthesized. • The clusters are constructed by the {Ti 3 ( μ 3 -O)} and {Ti 6 ( μ 3 -O) 6 } building units in a rarely observed assembly mode. • The clusters exhibit favorable catalytic activity towards the visible-light photocatalytic oxidative desulfurization. The 8-hydroxyquinoline functionalized titanium-oxo clusters (TOCs) of the formulation [Ti 9 ( μ 3 -O) 7 ( μ 2 -O) 3 ( μ 2 -O i Pr)(O i Pr) 5 (O 2 C t Bu) 9 (OQ)]·HO i Pr (HOQ = 8-hydroxyquinoline) and [Ti 12 ( μ 3 -O) 8 ( μ 2 -O) 6 ( μ 2 -O i Pr) 2 (O i Pr) 4 (O 2 C t Bu) 12 (OQ) 2 ]·4H 2 O were synthesized and structurally characterized by single-crystal X-ray diffraction. The assembly mode between the {Ti 3 ( μ 3 -O)} and {Ti 6 ( μ 3 -O) 6 } building units in the clusters has been rarely observed for titanium-oxo clusters. These two clusters exhibit intense visible absorption with narrow band gap of ~2.4 eV due to the presence of 8-hydroxyquinoline ligands. The clusters exhibit favorable catalytic activity for the visible-light-driven photocatalytic oxidative desulfurization (PODS) of dibenzothiophene. The results demonstrate that the core structure and functional ligands are important for the photocatalytic activity of titanium-oxo clusters.