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.