Phosphorous atom induced intramolecular charge transfer fluorescence in 9-diphenylphosphinophenanthrene

9-Diphenylphosphinophenanthrene (9DPP) in solutions at 298 K gives a broad ICT fluorescence spectrum centered at 510 nm in n-hexane. The origin of the ICT fluorescence is discussed on the basis of X-ray structure analysis, solvent effects on fluorescence, and MO calculations by contrast with 9-diphenylaminophenanthrene (9DAP).