Tetranuclear Zn(II) and mononuclear Ni(II) based coordination polymers derived from a pair of isomeric 1,2,4-triazole ligands 3,5-disubstituted by pyridine and acetate ethyl ester groups

摘要

A pair of isomeric compounds, namely L1-Et [2-(5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)acetate ethyl ester] and L3-Et [2-(5-(pyridin-3-yl)-4H-1,2,4-triazol-3-yl)acetateethylester], has been synthesized in this work, and they are used as multi-dentate ligands to react with certain transition-metal ions under solvothermal conditions. As a result, two three-dimensional (3D) coordination polymers, i.e. {[Zn(L1) (H2O)]ClO4 center dot 2H(2)O center dot 0.5MeOH}n (C1) and {[Ni(L2)(2)](ClO4)(2)center dot 2H(2)O} (C3), have been yielded and structurally characterized, where ligand L2 is found to be the decomposition product of ligand L3-Et. It is noted that a novel tetranuclear Zn-4(L1)(4) based cluster-organic framework is constructed in the case of C1 exhibiting a three-dimensional (3D) 2-fold interpenetrating diamond structure. By comparing the structures of C1 and C3, it is concluded that the competition between metal-ion complexation and ligand decomposition leads to the formation of different coordination polymers. (C) 2015 Elsevier Ltd. All rights reserved.