Zero-, one- and two-dimensional bis-triazole-bis-amide-based copper(II) complexes tuned by polycarboxylates with different protonation degrees: assembly, structures and properties

Abstract

Three bis-triazole-bis-amide-based copper(II) complexes with different dimensionality, [Cu(dtcd)2 (1,3-HBDC)2]·2H2O (1), [Cu(dtcd) (1,3,5-H2BTC)2]·2H2O (2) and [Cu4(μ3-OH)2(dtcd)2(SIP)2]·4H2O (3) (dtcd = N,N′-di(4H-1,2,4-triazole) cyclohexane-1,4-dicarboxamide, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, NaH2SIP = sodium 5-sulfoisophthalate), have been synthesized under different pH values and structurally characterized. Complex 1 exhibits a zero-dimensional mononuclear structure with one carboxyl group of 1,3-HBDC coordinating to copper(II), while the other carboxyl group is protonated. In complex 2, the CuII ions are bridged by the dtcd ligands forming a one-dimensional chain, in which only one carboxyl group of 1,3,5-H2BTC coordinates with the metal, while the others are protonated. Complex 3 possesses a two-dimensional network based on tetranuclear Cu4 clusters supported by the dtcd and nonprotonated SIP ligands. The various structures clearly indicate that the pH and polycarboxylates have a great influence on the dimensionality and structures of 1–3. The luminescence properties of 1–3 and magnetic properties of 3 were investigated.