Silver(I) coordination polymers generated from asymmetrical Schiff-base ligands containing triazolyl and pyridyl rings

Abstract

A series of the silver(I) complexes of the type {[Ag(L1)][X]}∞ [L1=4-(pyridin-2-yl)methyleneamino-1,2,4-triazole; X=PF6−, 1, BF4−, 2, ClO4−, 3, and NO3−, 4], {[Ag(L2)(CH3CN)][PF6]}n (L2=4-(pyridin-3-yl)methyleneamino-1,2,4-triazole), 5, and {[Ag(L2)][CF3CO2]}n, 6, have been prepared by reactions of various Ag(I) salts with L1 or L2 in CH3CN. All the complexes have been structurally characterized by X-ray crystallography confirming that complexes 1–4 are one-dimensional coordination polymeric chains, while complexes 5 and 6 are two-dimensional and three-dimensional coordination polymeric net and frameworks, respectively. All the L1 ligands in complexes 1–4 act as tridentate ligands to chelate and bridge Ag(I) ions. The anions PF6−, BF4− and ClO4− in complexes 1–3 are not coordinated to the Ag(I) atoms while the NO3− anions in complex 4 are coordinated to the metal centers through one of the three oxygen atoms. All the tridentate L2 ligands in complexes 5 and 6 bind soft acid Ag(I) ions through the triazole and pyridyl groups forming the two-dimensional and three-dimensional coordination polymeric net and frameworks, respectively, while the anions PF6− and CF3CO2− in complexes 5 and 6 are not coordinated to the Ag(I) atoms. The anions in complexes 1–6 play important roles in linking cationic chains or layers into 3-D supramolecular structures.