Syntheses, structures, and photoluminescence of five silver(i) coordination polymers based on tetrakis(imidazol-1-ylmethyl)methane

Abstract

In this article, five new silver(I) coordination polymers constructed from tetrakis(imidazol-1-ylmethyl)methane (L) and various anions have been synthesized, namely, [Ag(L)0.5](NO3)·0.5(H2O) (1), [Ag(L)0.25Br] (2), [Ag2L](mal)·6.25H2O (3), [Ag2L(1,3-bdc)]·4H2O (4), and [Ag2L(1,4-bdc)0.5]·0.5(1,4-bdc)·7.5H2O (5), where H2mal = maleic acid, 1,3-H2bdc = benzene-1,3-dicarboxylic acid, and 1,4-H2bdc = benzene-1,4-dicarboxylic acid. In compound 1, Ag(I) atoms are connected by the L ligands to form a 2D 4-connected square layer (sql) with free NO3− anions in the channels. The resulting layers are extended into 3D supramolecular frameworks through π–π interactions. In compound 2, the L ligands link the Ag4Br4 cluster to form a two-fold interpenetrating diamond (dia) architecture. When the dicarboxylate ligands H2mal, 1,3-H2bdc and 1,4-H2bdc were used in the reaction, compounds 3–5 were obtained. In compound 3, the Ag(I) atoms are bridged by the L ligands to furnish a 3D trinodal (3,4)-connected (62·8)(4·6·8)(4·62·82·10) net with the mal ligands just as free counteranions. In compound 4, the 1,3-bdc ligand coordinates to the Ag(I) center in a monodentate mode. The L ligands link the Ag(I) atoms to form a 2D double layer structure with point symbol (62·8)2(64.82). In compound 5, the L and 1,4-bdc ligands connect the Ag(I) atoms to form a complicated 3D (3,4)-connected framework with point symbol (4·102)2(42·6)2(42·103·12)(42·6·103)2. The influence of the anions on the structures of the coordination polymers has been discussed. Additionally, the luminescent properties of these compounds were also studied.