Two new Cd(II) coordination polymer based on Biphenyl-3, 3′, 5, 5′-tetracarboxylic acid

Abstract Two new cadmium (II) compounds, {[Cd(BPTC) 0.5 (4,4′-bipy) 0.5 (H 2 O)]·(H 2 O)} n ( 1 ) and {[Cd(BPTC) 0.5 (bbt)(H 2 O)]·(H 2 O)} n ( 2 ) have been synthesized based on the mixed ligands of H 4 BPTC, 4, 4′-bipy, and bbt (H 4 BPTC = Biphenyl-3, 3′, 5, 5′-tetracarboxylic acid, 4, 4′-bipy = 4, 4′-Bipyridine, bbt = 1, 4 - (3 - imidazole) - butane). Nitrogenous molecules 4, 4′-bipy (rigid) and bbt (flexile) are regarded as bridge ligands in these two polymer frameworks. In result, the crystal structures of 1 and 2 are ascertained, then PXRD, TG and PL properties are also measured. PXRD data confirm the phase purity of 1 and 2 . Compound 1 is a three dimensional (3D) porous framework of (3·4 2 ·6 2 ·12)(3 2 ·4 2 ·6 4 ·8 4 ·12 3 ) topology with dinuclear Cd(II) clusters as Secondary Building Unit (SBU). Compound 2 shows one dimensional (1D) arranged nano-channels, which are interlinked by hydrogen bonds to construct a 3D porous framework. All Cd(II) ions in 1 and 2 show pentagonal bipyramid coordination environments. Carboxyl displays three coordination modes of chelating, bidentate bridging, chelating-bridging. The effective porosities of 1 and 2 calculated by PLATON are 16.2% and 20.7%, whose skeletons are stable up to 321 °C and 335 °C respectively. This work may give an impetus to the further exploration of porous frameworks with other nitrogenous bridge ligands and H 4 BPTC.