Ionothermal synthesis and crystal structure of a luminescent bipyridine bridged Zn(II) complex

A luminescent complex, [Bmim]2[(ZnBr3)2(bpy)] (1) (bpy = 4,4′-bipyridine, bmim = 1-butyl-3-methyl imidazolium), has been synthesized through ionothermal reaction and characterized systematically. Complex 1 exhibits isolated structure of bipyridine bridged zinc bromide units, stacked with 1-butyl-3-methyl imidazolium layers. The luminescent property of 1 has been investigated and supported by density functional theory (DFT) calculations, where the emissions are assigned to the halide-to-ligand charge transfer (XLCT) mixed with some metal-to-ligand charge transfer (MLCT) and intraligand-charge-transfer (ILCT).