Syntheses, structures and photoluminescent property of coordination complexes with 2-(1H-1,2,4-triazol-1-yl)acetic acid

Reactions of ligand 2-(1H-1,2,4-triazol-1-yl)acetic acid (HL) with varied metal salts of Cu(II), Co(II), Ni(II), Zn(II), Cd(II) and Ag(I) result in formation of six new coordination complexes, {[Cu(L)2] · 3H2O}n (1), [Co(L)2(H2O)2]n (2), [Ni(L)2(H2O)2]n (3), [Zn(L)2(H2O)2]n, (4), [Cd(L)2]n (5) and [Ag(L)]n (6), and their structures were determined by X-ray crystallography. Complexes 1, 2, 3 and 4 with square-planar or octahedral metal centers have similar two-dimensional (2D) network structure with (4, 4) topology, while complex 5 displays a 2D structure with (6, 3)-connected topology. Complex 6 has a three-dimensional (3D) structure, in which the Ag(I) has tetrahedral coordination geometry. Ligand L− acts as a 2-connected rod (bridging ligand) in 1, 2, 3 and 4, and acts as 3-connected nodes in 5 and 6. The results indicate that the coordination modes of the ligand and metal centers have great influence on the structures of the complexes. In addition, the photoluminescent properties of ligand HL and complexes 4 and 5 were studied in the solid state at room temperature.