Assembly of Three Cadmium(II) Complexes Based on Flexible alpha,omega-Bis(benzimidazolyl)alkane Ligands

Three flexible α,ω-bis(5,6-dimethylbenzimidazolyl)alkane ligands with different spacers were reacted with CdX2 (X = Cl, Br, I) hydrothermally, resulting in three coordination architectures, namely [CdI2(L)]n (1), [CdBr2(L)]n (2), and Cd2Cl4(L)2 (3) [L1 = 1,3-bis(5,6dimethylbenzimidazole)propane, L2 = 1,5-bis(5,6-dimethylbenzimidazole)pentane, L3 = 1,6bis(5,6-dimethylbenzimidazole)hexane]. They have been characterized by elemental analyses, IR spectra, thermogravimetric (TG) analysis, and single-crystal X-ray diffraction. Complex 1 displays a helical chain linked by the ligands L1, and a 2D supramolecular network is constructed through π−π stacking interactions; complex 2 shows a helical chain structure with connections through two kinds of strong π−π stacking interactions into an intricate 3D supramolecular network; complex 3 contains dinuclear metallomacrocycles. The fluorescence properties of 1–3 have been investigated in the solid state.