Positional effects of fluorine substitution on room temperature phosphorescence in hexaphenylmelamine derivatives

Three hexaphenylmelamine phosphors substituted with fluorine at meta , ortho , and para positions were synthesized and characterized, showing increasing phosphorescence lifetimes and quantum yields. Crystal analysis and theoretical calculations suggest that the superior RTP of HPM- p -F is attributed to its higher oscillator strength, increased molecular binding energy, and favorable spin–orbit coupling.