One novel 3D tetranuclear cadmium coordination polymer based on 2,3′,4,5′-biphenyltetracarboxylic acid: Synthesis, crystal structure and luminescence

•3D tetranuclear cadmium MOFs•Novel 2-nodal 4, 10-c topological net•A potential blue light-emitting candidate

One novel 3D cadmium coordination polymer, namely, {[Cd2(bptc4 −)(ox2 −)0.5(H2O)2] · 4.5H2O}n (1), has been hydrothermally synthesized through a reaction of 2,3′,4,5′-biphenyltetracarboxylic acid (H4bptc) with divalent cadmium salt in the presence of a second ligand (ox = oxalic acid). X-ray single crystal structure analysis reveals that tetranuclear cadmium clusters are formed by linking two Cd1 and two Cd2 ions with carboxyl groups. Each ox2 − ligand, with a bidentate chelating mode, connects two Cd2 ions from two adjacent tetranuclear clusters to afford 1D zigzag cadmium cluster chains. Furthermore, 1D chains are connected by bptc4 − ligands to extend a 3D framework with one-dimensional channels along the [001] direction. From a topology view, complex 1 exhibits an unprecedented 2-nodal 4, 10-connected net with the Schläfli symbol of {46}2{49. 512.622.72}. The luminescence analyses reveal that complex 1 shows an emission maximum at 437 nm, which may be attributed to the intra-ligand transition. A red shift of 31 nm compared with H4bptc ligand was observed and the luminescent decay lifetime is 2.74 ns, which indicates that it might be a potential blue light-emitting candidate. In addition, it was also characterized by elemental, IR spectra, PXRD and TG analyses.

Graphical abstractOne novel 3D tetranuclear cadmium coordination polymer is synthesized and characterized. 1D zigzag cadmium cluster chains are formed through linking two adjacent tetranuclear cadmium clusters with ox2 − ligands. The whole framework exhibits an unprecedented 2-nodal 4, 10-connected net with the Schläfli symbol of {46}2{49. 512.622.72}.Figure optionsDownload full-size imageDownload as PowerPoint slide