Dicarboxylate Ligands Oriented Assembly of {Ti3(μ3-O)} Units: From Dimer to Coordination Triangles and Rectangles.

A series of dicarboxylates bridged titanium-oxo clusters with {Ti3(μ3-O)} building units have been synthesized through facile one-step solvothermal reactions. It is interesting to find that the geometric characteristics of the obtained supramolecular structures highly depend on the configuration of the applied dicarboxylate ligands. A linear dimeric [Ti3O]2L2 complex can be constructed using flexible cyclohexanedicarboxylic acid, while the introduction of rigid 2-nitro-1,4-benzenedicarboxylic acid gives rise to a triangular [Ti3O]3L3 structure. Moreover, unusual [Ti3O]4L4 rectangles have been achieved with more symmetric 5-nitro-1,3-benzenedicarboxylic acid or terephthalic acid. Furthermore, a photochromic effect is observed on the obtained complexes upon UV-vis light irradiation in the presence of alcohol.