The triple fluorescence of benzanilide and the dielectric medium modulation of its competitive excitation

• Published in: Chemical physics letters 1988-09, Vol.150 (6), p.433-436
• Main Authors: Heldt, Jozef, Gormin, David, Kasha, Michael
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Exact sciences and technology; Fluorescence and phosphorescence; radiationless transitions, quenching (intersystem crossing, internal conversion); Molecular properties and interactions with photons; Physics
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/0009-2614(88)80432-9

The fluorescence of the benzanilide molecule at 298 K is inferred to consist of three independent electronic transitions associated with the single ground-state molecular species. F 1 (λ max340 nm), the normal fluorescence is observed weakly and is ascribed to an n,π*,-π,π* mixed state. F′ 2 is ascribed to the proton-transfer imidol tautomer fluorescence (previously reported) with unresolved λ max (inferred at ≈460 nm). F″ 2 is ascribed to a charge-transfer state fluorescence to the ground state, and occurs as a resolved CT transition in tetrahydrofuran at λ max 520 nm. Comparison of the spectra of N-methylbenzanilide exhibiting only F 1 and F″ 2 (CT) permitted the analysis of the benzanilide spectra.