Cadmium carboxycinnamate coordination polymers with dimensionality differences depending on dipyridyl ligand

•Three new cadmium carboxycinnamate coordination polymers.•Nature of dipyridyl coligand dictates dimensionality and topology.•(4, 4) Grid with kinked dipyridyl ligands penetrating through the grid apertures.•(6, 3) Herringbone and 3-D 6-connected topologies for longer dipyridines.•Moderate to intense blue-violet emission upon UV irradiation.

Hydrothermal reaction of cadmium nitrate, carboxycinnamic acid (H2cca), and a tethering hydrogen-bonding capable dipyridyl ligand afforded three new crystalline coordination polymers, which were characterized by single-crystal X-ray diffraction. {[Cd(cca)(dpa)2]·2H2O}n (1, dpa = 4,4′-dipyridylamine) shows a (4, 4) coordination polymer layer, but with pendant dpa ligands curling in through the grid apertures. {[Cd(cca)(4-bpmp)(H2O)]·2H2O}n (2, 4-bpmp = bis(4-pyridylmethyl)piperazine) also has a 2-D coordination polymer layer structure, but with closely interdigitated (6, 3) herringbone motifs. [Cd(cca)(4-bpfp)]n (3, 4-bpfp = bis(4-pyridylformyl)piperazine) manifests a {Cd2(OCO)2} dimer-based 6-connected pcu 3-D network. All three materials undergo modest to strong blue-violet fluorescence under ultraviolet radiation. Thermal decomposition behavior is also probed.

Graphical abstractThree strongly luminescent cadmium carboxycinnamate coordination polymers with hydrogen-bonding capable dipyridyl ligands were prepared. {[Cd(cca)(dpa)2]·2H2O}n (1, dpa = 4,4′-dipyridylamine) shows a (4, 4) coordination polymer layer, but with pendant dpa ligands curling in through the grid apertures. Interdigitated (6, 3) herringbone layers and a dimer-based pcu 3-D network are seen for longer dipyridyl ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide