Mononuclear complexes [Cd(HMPCA)2(H2O)4] (1) and [Co(H2MPCA)2(DMF)2(H2O)2]Cl2 (2), and 3D coordination polymer [Cd3Cl2(HMPCA)4(H2O)2]·2H2O (3) (H2MPCA = 3-methyl-1H-pyrazole-4-carboxylic acid) were synthesized and characterized by elemental analysis, IR spectra, thermogravimetric analysis, and X-ray single-crystal structure analysis. In 3, HMPCA− anions bridged trinuclear Cd(II) ions clusters to form an 8-connected 3D network with channels. The complexes all display green fluorescence in the solid state. As a bifunctional catalyst, complex 2 exhibited excellent catalytic activity for oxygen evolution reaction (OER), and certain catalytic activity for oxygen reduction reaction (ORR).
