Electron-density distribution tuning for enhanced thermal stability of luminescent gold complexes

Abstract

Structure–property relationships of newly synthesized luminescent gold complexes were examined from the viewpoint of material applications. In particular, we investigated the effect of controlling the molecular electron-density distribution by introducing trifluoromethyl substituents into the complexes. The structures of the molecular aggregates were not affected by the trifluoromethyl substituents, as all the complexes formed antiparallel dimers in the crystal state. Moreover, we found that the trifluoromethyl substituents enhanced the thermal stability of the complexes without significantly changing the luminescence behaviour. Thus, while the thermal stability of these materials depends on the molecular structure, i.e. the molecular electron-density distribution, the luminescence behaviour mainly depends on the molecular aggregate structure. These results suggest that various material properties, e.g. luminescence colour and thermal stability, can be controlled independently by tuning the structures of molecules and molecular aggregates using trifluoromethyl substituents.