The [Cu2Br2(DIB)2(PPh2)2]n complex, obtained by the reaction between [Cu4Br4(PPh3)4] and 1,4-diisocyanobenzene (DIB), was found to have a bridged polymeric structure with a planar {Cu2Br2} core. The compound exhibited bluish-green (max = 498 nm) and green (max = 515 nm) luminescence at 295 and 77 K, respectively, corresponding to the emissions from XLCT (HE band) and (X+M)LCT (LE band), respectively. The dual emission, which is attributed to the luminescence from both bands, was observed at around 178 K. The complex also displayed a change in luminescence color from bluish-green to yellow (max = 529 nm) upon applying external mechanical stimuli. The film containing [Cu2Br2(DIB)2(PPh2)2]n was prepared by a cast method using polymethyl methacrylate as a binding agent. The rubbed part of the film turned yellow and the other parts maintained bluish-green luminescence. Restoration of the initial color was feasible by annealing, even in film state.

We herein describe the synthesis of 3ʹ-aminofluorene-9-spiro-5ʹ-imidazolidine-2ʹ,4ʹ-dithione through the reaction of fluorene-9-spiro-4ʹ-thiazolidine-2ʹ,5ʹ-dithione with hydrazine, and subsequent investigation of the interactions of the synthesized spirocycle-containing imidazolidinedithione with organic solvents. Recrystallization from a solvent containing benzene led to the formation of an inter-molecular compound consisting of 3ʹ-aminofluorene-9-spiro-5ʹ-imidazolidine-2ʹ,4ʹ-dithione and benzene in a 2:1 ratio through both intramolecular N-H•••S hydrogen bonds and additional weak N-H••• interactions. The trapped benzene molecule was reversibly released by dissolution of the inter-molecular compound in acetone and subsequent concentration under reduced pressure at room temperature, and also by heating at 130-150 °C.