Diverse CdII coordination complexes derived from bromide isophthalic acid binding with auxiliary N-donor ligands

Abstract The coordination characteristics of 4-bromoisophthalic acid (4-Br-H 2 ip) have been investigated in a series of Cd II -based frameworks. Hydrothermal reactions of Cd II salts and 4-Br-H 2 ip together with flexible or semiflexible N-donor auxiliary ligands resulted in the formation of four three-dimensional coordination complexes with diverse structures: {Cd(bix) 0.5 (bix) 0.5 (4-Br-ip)]·H 2 O} n ( 1 ), [Cd(bbi) 0.5 (bbi) 0.5 (4-Br-ip)] n ( 2 ), {[Cd(btx) 0.5 (4-Br-ip)(H 2 O)]·0.5CH 3 OH·H 2 O} n ( 3 ) and {[Cd(bbt) 0.5 (4-Br-ip)(H 2 O)]·3·5H 2 O} n ( 4 ). These compounds were characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction. They displayed diverse structures depending on the configuration of the 4-connected metal node, the coordination mode of the 4-Br-H 2 ip, the coordination ability and conformationally flexibility of the N-donor auxiliary. Compound 1 exhibits 3-fold interpenetrated 6 6 topology and compound 2 has a 4 12 topology. Compounds 3 – 4 have similar 3D pillar-layered structures based on 3,4-connected binodal net with the Schlafli symbol of (4·3 8 ). The thermal stabilities and photoluminescence properties of them were discussed in detail.