Highly Efficient Solid-State Phosphorescence of Platinum Dihalide Complexes with 9-Phenyl-9-arsafluorene Ligands

Platinum dihalide (chloride, bromide, and iodide) complexes with 9-phenyl-9-arsafluorene, which can be safely prepared and are air stable, were synthesized. The dibromide and diiodide complexes showed highly efficient phosphorescence even at 298 K in the solid state, and their quantum yields were up to a value of 0.52. The structures of the complexes were analyzed by X-ray crystallography. Time-dependent density functional calculations support our understanding of the initial electron transition processes. The rigid and bulky structure of the arsafluorene backbone effectively induced solid-state phosphorescence unlike that of a triphenylarsine analogue, which has three unbridged phenyl groups.