A three-dimensional CdIIcoordination polymer constructed from 1,1′-biphenyl-2,2′,5,5′-tetracarboxylate and 1,4-bis(1H-imidazol-1-yl)benzene ligands
The title coordination polymer, poly[[aqua(μ5-1,1′-biphenyl-2,2′,5,5′-tetracarboxylato)bis[μ2-1,4-bis(1H-imidazol-1-yl)benzene]dicadmium(II)] dihydrate], {[Cd2(C16H6O8)(C12H10N4)2(H2O)]·2H2O}n, was crystallized from a mixture of 1,1′-biphenyl-2,2′,5,5′-tetracarboxylic acid (H4bpta), 1,4-bis(1H-imidazol-1-yl)benzene (1,4-bib) and cadmium nitrate in water–dimethylformamide. The crystal structure consists of two crystallographically independent CdIIcations, with one of the CdIIcations possessing a slightly distorted pentagonal bipyramidal geometry. The second CdIIcentre is coordinated by carboxylate O atoms and imidazole N atoms from two separate 1,4-bib ligands, displaying a distorted octahedral CdN2O4geometry. The completely deprotonated bpta4−ligand, exhibiting a new coordination mode, bridges five CdIIcations to form one-dimensional chainsviaμ3-η1:η2:η1:η2and μ2-η1:η1:η0:η0modes, and these are further linked by 1,4-bib ligands to form a three-dimensional framework with a (42.64)(4.62)(43.65.72) topology. The structure of the coordination polymer is reinforced by intermolecular hydrogen bonding between carboxylate O atoms, aqua ligands and crystallization water molecules. The solid-state photoluminescence properties were investigated and the complex might be a candidate for a thermally stable and solvent-resistant blue fluorescent material.