Triazole based Ag coordination clusters: synthesis, structural diversity and anion exchange properties

Abstract

In this work two new multi-dentate 1,2,4-triazole derivate ligands 4-(4-methyl-2-pyridine)-1,2,4-triazole (L₁), 4-(5-methyl-3-pyridine)-1,2,4-triazole (L₂) have been designed and synthesized. Three novel cluster-based cationic silver(I) coordination compounds with L₁ and L₂, namely [Ag₂(H₂O)₄(L₁)₂](CF₃CO₂)₂ (1), [Ag₄(L₁)₆](BF₄)₄ (2) and {[Ag₂(H₂O)(L₂)₂]·(BF₄)₂}_n (3) have been isolated. When L₁ and different Ag(I) salts are used, the bi-nuclear Ag(I) cluster 1 and the tetra-nuclear Ag(I) cluster 2 can be isolated indicating anion induced structural diversity. Further when L₂ is used, 3 can be isolated. 3 is a 2D clustered-based coordination compound based on bi-nuclear Ag(I) clusters. PXRD patterns and solid state luminescent properties of 1–3 have been investigated. Further anion exchange properties 2 and 3 also have been investigated. 2 and 3 present novel examples of triazole–silver(I) coordination compounds for effectively capturing the anion pollutants Cr₂O₇²⁻, MnO₄⁻ in water solutions and Congo Red in methanol solutions through the anion exchange process.