Synthesis, Crystal Structure, and Luminescent Properties of Ni(II), Zn(II), and Cd(II) Coordination Compounds with 1-(5-methyl-1H-pyrazol-3-yl)-1,2,3-Triazole-4-Carboxylic Acid

New coordination Ni(II), Zn(II), and Cd(II) compounds with 1-(5-methyl-1H-pyrazol-3-yl)-1,2,3-triazole-4-carboxylic acid (H2L) are prepared and characterized. It is established by SCXRD that [Ni(HL)2(H2O)2]·2H2O and [Zn(HL)2(H2O)2]·2H2O are isostructural discrete complexes with a ligand coordinated in the N,O-bidentate chelate mode. A [Zn(HL)2]n 1D metal-organic framework with bridging carboxylate groups is prepared by changing the synthesis conditions. The interaction of H2L with cadmium perchlorate leads to the formation of the [Cd(HL2]n layered 2D metal-organic framework bearing a ligand coordinated in the N,O,O-tridentate mode via the pyrazole ring′s nitrogen atom and the bridging carboxylate group. The cadmium coordination polymer exhibits two-band luminescence with maxima at 460 nm and 530 nm.