Syntheses, structures and photoluminescence of zinc(ii) and silver(I) coordination polymers based on 1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole) and different carboxylate ligands

Eleven compounds, [Zn(L1)2(bbmi)] (1), [Zn(HL2)2(bbmi)] (2), [Zn0.5(L3)(bbmi)0.5] (3), [Zn0.5(L4)(bbmi)0.5(H2O)] (4), [Zn(L5)2(bbmi)] (5), [Zn(L6)(bbmi)] (6), [Zn(L7)(bbmi)0.5(H2O)] (7), [Zn(L8)(bbmi)0.5(H2O)] (8), [Ag2(L6)(bbmi)(H2O)] (9), [Ag(L9)0.5(bbmi)0.5]·2H2O (10) and [Ag2.5(L10)(bbmi)2]·0.5(OH)·0.5(EtOH)·1.5H2O (11), where bbmi = 1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole), HL1 = benzoic acid, H2L2 = salicylic acid, HL3 = p-nitrobenzoic acid, HL4 = nicotinic acid, HL5 = 3,5-dinitrobenzoic acid, H2L6 = o-phthalic acid, H2L7 = m-phthalic acid, H2L8 = fumaric acid, H2L9 = p-phthalic acid and H2L10 = 5-aminoisophthalic acid, have been synthesized and characterized. Compounds 1–5 and 10 display one-dimensional chain structures. These chains are connected through intermolecular interactions to form 2D supramolecular structures, respectively. The layers of 2 are further connected through C–H⋯π interactions to yield a 3D supramolecular structure. There exist weak Ag⋯Ag interactions in 10, which also contribute to the stabilization of the supramolecular layer. Compound 6 exhibits a diamondoid network. Compound 7 shows a 2D (4,4) layer. The structure of 8 is a 3D α-Po framework. Compound 9 displays a 2D layer structure. Furthermore, the π–π interactions among the bbmi ligands link the layers into a 3D supramolecular framework. Compound 11 shows a ladder structure. The Ag⋯Ag and π–π interactions further connect the ladders to form a 2D supramolecular assembly. The thermal stabilities of 4 and 7–11 and the luminescent properties of 1, 3–5 and 7–11 in the solid state are also discussed.