Green-blue light-emitting platinum(ii) complexes of cyclometallated 4,6-difluoro-1,3-dipyridylbenzenes showing mesophase organisation

Abstract

Blue-green light-emitting phosphorescent Pt^II complexes of 1,3-bis(2-pyridyl)benzene are reported that incorporate hexadecyl-containing fragments in the 5-position of the pyridine rings. Along with the more classical half disc-shaped hexacatenar molecule with six pendant alkoxy chains, which shows an Rm mesophase, the simpler complex functionalised by just two alkoxy chains, one at each pyridyl 5-position, was also found to be mesomorphic. The luminescence of pure films obtained from these complexes is orange-red, dominated by the excimer-like emission, and is independent of the thermal history of the film. The mesophases of the complexes are three-dimensional and columnar in nature – all are based on a two-dimensional hexagonal arrangement extended into the third dimension.