Substituted benzoate-anchored decanuclear titanium-oxo clusters featuring an unprecedented defective double-cubane geometry

Abstract

Based on DMF solvent, four titanium-oxo clusters (TOCs) [Ti₁₀(μ₃-O)₁₂(L)₆(OⁱPr)₁₀(DMF)₂] (Ti–L) (L = 4-methylbenzoate (MB), 3,5-di-tert-butylbenzoate (DTBB), 4-methoxybenzoate (MOB) and 4-methyl-3,5-dinitrobenzoate (MDNB)) with the same coordination environments have been solvothermally synthesized with high yield between benzoic acid derivatives and Ti(OⁱPr)₄. Single crystal X-ray diffraction analysis confirmed that Ti–L presents an open cage-like structure made up of a substituted benzoate-anchored decanuclear titanium-oxo cluster featuring an unprecedented defective double-cubane geometry. The photophysical performance of Ti–L demonstrated that strong electron-withdrawing substituent groups on the benzoate skeleton are beneficial to the redshift of the absorption position and the decrease of the band gap for the TOCs. Due to the synergistic effects of its lowest band gap and open cage-like structure, Ti–MOB exhibited effective photocatalytic degradation of rhodamine B.