Exploring methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate and varying flexible bis(imidazole)-based synthons as building blocks for the construction of diverse cadmium coordination polymers

Abstract Three Cd(II)-based coordination polymers (CPs) with unique structures and topologies, namely, [Cd 2 (L) 2 (bimb) 2 (H 2 O) 2 ] n ( 1 ), {[Cd(L)(bmib) 0.5 (H 2 O)](CH 3 OH) 0.5 } n ( 2 ) and [Cd(L)(beib) 0.5 (H 2 O)] n ( 3 ) (H 2 L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, bimb = 1,4-bis(imidazol-1′-yl)butane, bmib = 1,4-bis(2-methylimidazolyl)butane and beib = 1,4-bis(2-ethylimidazolyl)butane) have been successfully constructed and characterized by single crystal X-ray structure determination, IR spectra, elemental analyses and powder X-ray diffractions. X-ray results showed compound 1 features a new 2-nodal 5,6-connected 3D network with a point symbol of {4 5 .5.6 3 .7} 2 {4 2 .5 4 .6 9 }. Compound 2 exhibits a rare 6-fold interpenetrating dia 3D network. Compound 3 bears a hydrogen bonded-extended 3D supramolecular structure based upon sql layers assembled from dinuclear Cd(II) units. Thermal stability and solid photoluminescence properties of compounds 1 – 3 were studied. Significantly, compound 1 can sense nitrobenzene through the luminescence quenching effect.