Diverse stacked and entangled topologies in cadmium tricarballylate coordination polymers with nitrobenzene detection capability

Abstract

Hydrothermal reaction of cadmium salts, tricarballylic acid (H3tca) and dipyridyl ligands resulted in generation of four coordination polymers that were characterized by single-crystal X-ray diffraction. The nature of the ancillary dipyridyl ligand plays a primary role in enforcing differing structural topologies across the series of new phases. [Cd2(tcaH)2(dpe)2]n (1, dpe = 1,2-di(4-pyridyl)ethane) displays a 2-fold interpenetrated 3D 41263pcu net based on 6-connected {Cd2(O)(OCO)} cluster nodes. [Cd(tcaH)(dpp)(H2O)]n (2, dpp = 1,2-di(4-pyridyl)propane) manifests a 1D + 1D → 3D interlocked system of loop-containing perpendicular ribbon motifs. {[Cd4(tca)2(Htca)(bpmp)5(H2O)2]·27H2O}n (3, bpmp = bis(4-pyridylmethyl)piperazine) has intersecting [Cd4(tca)2(Htca)(H2O)2]n layer, [Cd(bpmp)(H2O)]n chain, and [Cd2(bpmp)3]n ladder submotifs and forms a complicated 3,4,5-connected trinodal 3D self-penetrated network with (6.92)(42638)(42638.9310) topology. {[Cd(tcaH)(Hbpmp)](ClO4)·5.5H2O}n (4) exhibits stacked cationic bilayer (4,4) grid slabs. All compounds showed potential as potential detectors for nitrobenzene in ethanol suspension via luminescence quenching, with 1 showing the highest uptake of analyte.