Two binuclear tetracarboxylate-bridged complexes: syntheses, structures, and properties

Cu-2(C9N5H9)(2)(C6H5CO2)(4) (1) and Zn-2(C9N5H9)(2)(C10H7CH2CO2)(4) (2) have been synthesized by hydrothermal methods with 2,4-diamine-6-phenyl-1,3,5-triazine (phdat) and aromatic carboxylic acid (benzoic acid (ba) or naphthylacetic acid (naa)) as ligands and characterized by single-crystal X-ray diffractions, elemental analyses, infrared spectra, magnetism, fluorescence spectra, and thermogravimetric analyses. In 1 and 2, the two metals are bridged by four carboxylates in paddle-wheel-shaped binuclear [M-2(CO2)(4)] units (M=Cu (1) and Zn (2)) and coordinated by one nitrogen from phdat, forming five-coordinate centers. The temperature-dependent magnetic susceptibility of 1 was obtained from 300 to 2 K, showing an anti-ferromagnetic interaction between Cu(II)'s. Compound 2 exhibits solid state fluorescence at 404 nm upon excitation at 304 nm.