4-Chlorosalicylate-stabilized titanium-oxo clusters with structures mediated by tetrazole and their photophysical properties

Three 4-chlorosalicylate-stabilized titanium-oxo clusters (TOCs), namely, H-2[Ti-4(mu(2) O)(2)(mu(2)-OiPr)(2)(OiPr)(6)(CISal)(4)] (CISal = 4-chlorosalicylate), H[Ti-14(mu(3)-O)(7)(mu 2-O)(2)(mu(2)-OiPr)(2)(OiPr)(9)(CISal)(8)], and H-2[Ti-14(mu(3)-O)(8)(mu(2)-O)(4)(mu(2)-OiPr)(4)(OiPr)(14)(OH2)(0.5)(CISal)(8)]center dot 2H(2)O were synthesized and structurally characterized by single-crystal X-ray diffraction analysis. It is interesting that tetrazole exhibits structure-directing effect in the reaction between Ti(OiPr)(4) and 4-chlorosalicylic acid. The band-gap energies were modulated by different Ti-oxo core structures of these 4-chlorosalicylate-stabilized titanium-oxo clusters. DFT calculations reveal that the ligand-to-core charge transfer (LCCT) from the 4-chlorosalicylate to the cluster core is responsible for the low-energy charge transfer states. The photocurrent response and dye degradation experiments show that the Ti-oxo core structures have significant influence on the photoelectrochemical and photocatalytic properties of these 4-chlorosalicylate-stabilized titanium-oxo clusters. (C) 2018 Elsevier Ltd. All rights reserved.