Anion-induced assembly of two distinct copper(II) coordination polymers with a versatile multidentate N-donor ligand

Reaction of a ligand N-(3,5-di-2-pyrazinyl-4H-1,2,4-triazol-4-yl)-2-pyrazinecarboxamide (Hpztp) with CuSO4 and Cu(acac)2 (acac = acetylacetonate), respectively, yields two distinct CuII coordination polymers {[Cu3(pztp)2(SO4)2(H2O)2]·3H2O}n and {[Cu(pztp)(acac)]·0.5H2O}n. Both complexes have been structurally determined and also characterized by physicochemical and spectroscopic methods. The results reveal that by using different anions (SO42− versus acac−), the dimensionality (from 2D to 1D) of the resulting coordination architectures as well as conformations and binding fashions of the pztp ligand are significantly changed. That is to say, the selection of anions will play a key role in inducing the formation of the crystalline materials. The thermal stabilities of both complexes have also been explored and discussed.