Temperature induced two new trinuclear Co(II) cluster-based compounds: Luminescent, photocatalytic and anti-breast cancer properties

Two new trinuclear Co(II) cluster-based compounds, namely [Co3(L)2(H2O)4]n (1) and [Co1.5(L)(H2O)2]n (2) (H3L = biphenyl-3,4’,5-tricarboxylic acid), have been synthesized under hydrothermal conditions via tuning reaction temperature. Single crystal X-ray diffraction analyses revealed that both compound 1 and 2 contain trinuclear Co(II) cluster subunits: trinuclear [Co3(COO)4(H2O)2] cluster for 1 and trinuclear [Co3(COO)6] cluster for 2. Due to the different coordination modes of L3− ligand, compound 1 features a (3,6)-connected 3D framework with a rtl-type topology, and compound 2 features a (3,6)-connected 3D framework with a new topology which has not been reported in the TOPOS and RCSR database. The thermal stabilities and luminescent properties for the two compounds have been investigated. The photophysical properties studies showed that compounds 1 and 2 are excellent candidiates as potential semiconductive materials. Moreover, compounds 1 and 2 exhibit high photocatalytic efficiency for the degradation of methylene blue (MB) under UV light irradiation. In addition, the cytotoxicity of complexes 1 and 2 has been evaluated against three human breast cancer cells (MCF-7, MDA-MB-231 and BT-549) via the MTT assay.