High Efficiency Electrochemiluminescence for Copper(II) and Cadmium(II) Pyrazolate Polymers

Two new coordination polymers, namely, [Cu2(L)2(4,4′-bpy)]n (1) and [Cd(HL)Cl(1,10′-phen)]n (2) (H2L = 1H-pyrazole-3-carboxylic acid, 4,4′-bpy = 4,4′-bipyridine, 1,10′-phen = 1,10-phenanthroline) have been synthesized via solvothermal method and were structurally characterized by single-crystal X-ray diffraction, FT-IR, elemental analysis and PXRD. The two complexes are both infinite 1D chain structures, in complex 1 the H2L ligands are completely deprotonated and chelating the metal centers, while in complex 2, H2L ligands play a role in chelating-bridging the metal centers. What’s more, the two complexes further extended to 3D supramolecular networks by hydrogen bonds and weak C–H⋯π interactions. The weak intermolecular interactions existed in the complexes structures were further studied by Hirshfeld surface analysis and 2D fingerprint plots. In addition, these two transition mental complexes exhibit high intense electrochemiluminescence (ECL) in N,N-dimethylformamide (DMF) and after ten circulations the ECL intensity still remains stable, which can be a useful guide for the construct of new polymers ECL materials.