title: Excited-state intramolecular charge transfer in 9-aminoacridine derivative.
abstract: A new fluorochromic dye was obtained from the reaction of 9-aminoacridine with ethyl-2-cyano-3-ethoxyacrylate. It displays complex fluorescence that is ascribed to normal emission from the acridine chromophore in addition to excited-state intramolecular charge transfer (ESICT) formed upon light excitation. The analysis of the fluorescence decays in different solvents reveals two short-lived components in the range of 80-450 ps and 0.7-3.2 ns, ascribed to the formation and decay of the intramolecular charge transfer (ICT) state, in addition to a third component of about 9.0 ns, which is related to the normal emission from the acridine singlet excited state, probably in an enol-imine tautomeric form. The ICT emission is readily quenched by water addition to polar solvents, and this effect is ascribed to changes in the keto-amine/enol-imine equilibrium of this fluorochromic dye.
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, 13560-590, São Carlos SP, Brazil.
authors.forename: Robson Valentim
authors.initials: RV
authors.lastname: Pereira
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Garcia Ferreira
authors.forename: Marcelo Henrique
authors.initials: MH
authors.lastname: Gehlen
mesh_terms: D000585:Aminacrine / Q000737:chemistry*; D002853:Chromatography, Liquid; D004735:Energy Transfer; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010777:Photochemistry; D012997:Solvents / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D005456:Fluorescent Dyes; D012997:Solvents; D000585:Aminacrine