Reversible photoluminescence switching behavior and luminescence thermochromism of copper(I) halide cluster coordination polymers

Two novel coordination polymers [Cu3I4(C16H32N4)]·ClO4 (1) and [Cu6I6Br2(C16H32N4)(CH3CN)2] (2) (C16H32N4·2Br− = 4-Aza-1-azoniabicyclo-[2.2.2]octane, 1,1′-(1,4-butanediyl)bis-dibromide) have been synthesized under solvothermal conditions. At room temperature, compounds 1 (Φ = 46.2%) and 2 (Φ = 26.62%) show strong photoluminescence in solid state. At low temperature, compound 1 displays obvious thermochromic luminescence while compound 2 has no obvious change which can be observed by naked eye. However, compound 2 displays a interesting phenomenon. The luminescence of compound 2 is reversible when the coordinated CH3CN molecules in structure are removed by heat and recovered from acetonitrile solvent.