Fine Tuning of the Cu(II)-Bis(imidazole) Networks by Changing Sulfonate Anions

Abstract

In this paper, seven new compounds [Cu(biim-4)2(L1)2] (1), [Cu(biim-4)2(L2)2] (2), [Cu(biim-4)2(H2O)](L3)2·H2O (3), [Cu(L4)2](H2biim-4)·8H2O (4), [Cu(biim-4)1.5(H2O)3](L5)·2H2O (5), [Cu(biim-6)3](L1)2 (6), and [Cu(biim-6)3](L2)2·H2O (7), where HL1 = 3-amino-4-methylbenzenesulfonic acid, HL2 = 2-amino-3,5-dimethylbenzenesulfonic acid, HL3 = 4-amino-2,5-dichlorobenzenesulfonic acid, H2L4 = 8-hydroxyquinoline-5-sulfonic acid, H2L5 = 1,5-naphthenedisulfonic acid, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), and biim-6 = 1,1′-(1,6-hexanediyl)bis(imidazole), were successfully synthesized. The sulfonate anions of compounds 1, 2, and 4 coordinate to copper ions, while the sulfonates of 3 and 5–7 only act as counterions. In compounds 1–3, 6, and 7, copper ions are bridged by biim-4 or biim-6 ligands to form two-dimensional (2D) polymeric networks; in compound 5, copper ions are bridged by biim-4 ligands to form a one-dimensional (1D) ladder structure. In 4, [Cu(L4)2]2– anions, [H2biim-4]2+ cations and lattice–water molecules are linked through hydrogen bonds and π−π interactions to give a three-dimensional (3D) supramolecular framework.