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.