The interaction of singlet 9-cyanophenanthrene with mono- and diaminoalkanes in hexane solution yields weakly fluorescent exciplexes. Whereas the fluorescence quenching constant for 9-cyanophenanthrene is nearly the same for all mono- and diamines (1.5 × 1010 M-1 s-1), the lifetime of the exciplexes appears to be highly dependent upon the diamine chain length. The pronounced shortening of the exciplex lifetimes from about 15 ns to 300 ps for diamines with less than five methylene groups is interpreted in terms of the formation of a triplex between the 9-cyanophenanthrene anion radical and a σ-bonded amine dimer cation radical.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry