Cu(II)/Zn(II) Coordination Polymers Constructed by 3-(4′-Carboxy-phenoxy)benzoic Acid: Synthesis, Crystal Structure and as a Fluorescence Sensor to Acetone and Tb3+ Ion

Taking 3-(4'-carboxyl-phenyloxy) benzoic acid (3,4'-H(2)oba) and phenanthroline (phen) as ligands, two coordination polymers (CPs) [M(3,4'-oba)(phen)(H2O)] n (M=Zn (1), Cu (2)) were synthesized by hydrothermal method and their structures were characterized by X-ray single crystal diffraction. CP 1 features a one-dimensional chain structure. The coordination environment of Zn2+ ion is [ZnO3N2], forming tetragonal vertebral configuration. The Zn2+ ions are linked by 3,4'-oba ligands through mu(1):eta(1)eta(0)/mu(1):eta(1)eta(0) coordination modes. CP 2 has a structure with [CuO4N2] coordination unit. Ligand 3,4'-oba uses the pattern of mu(1):eta(1)eta(0)/mu(1):eta(1)eta(1) to connect two Cu2+ to form a 1D zigzag chain structure. The 1D chain forms a 2D supramolecular network structure through hydrogen bonds (C-H center dot center dot center dot O in 1 and O-H center dot center dot center dot O in 2). Ligand phen coordinates with Zn2+/Cu2+ by bidentate chelation mode. CP 1 showed strong fluorescence, which is attributed to the pi*-pi transition of the ligand. The fluorescence properties of 1 in different solvents and the fluorescence sensitization effect on lanthanide metal ion were studied. The fluorescence of CP 1 was quenched by acetone molecule, and it can sensitize the rare earth metal Tb3+ ions to emit strong green fluorescence. Therefore, 1 can be used as a fluorescence sensor for detecting acetone molecule and Tb3+ ion. CCDC: 2005286, 1; 2005285, 2.