Temperature effect-driven assembly of [CunXn]-based coordination polymers from CuX and 1,4-bis(imidazol-1-yl)butane

Three [CunXn]-based (X = Br, I) coordination polymers, {[Cu2(μ-I)2(bimb)2]·iodobenzene}n (1), {[Cu4(μ3-I)4(bimb)2][Cu2(μ-I)2(bimb)]}n (2) and {[Cu2Br(bimb)2]Br}n (3) were prepared from solvothermal reactions of CuX (X = I, Br) with 1,4-bis(imidazol-1-yl)butane (bimb) at different temperatures. These compounds were characterized by elemental analysis, IR, and single crystal X-ray diffraction. Compound 1 contains a rhombic [Cu2(μ-I)2] dimer that acts as a planar four-connected node to link four equivalent ones via bimb bridges to form a 2D (4,4) network. Each layer is further stacked by π–π interactions to form a 3D structure with 1D rhombic channels occupied by the guest iodobenzene molecules. Compound 2 consists of [Cu2(μ-I)2] dimers and [Cu4(μ3-I)4] tetramers which are interconnected by bimb bridges to generate another 2D network. Compound 3 contains [Cu2Br(bimb)2]+ cations that are linked by bimb ligands to form a 1D cationic chain. We also investigated the solid state photoluminescent properties of 1–3 at ambient temperature. The results provide an interesting insight into how reaction temperatures exert a great effect on the assembly of [CunXn]-based coordination polymers.