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.

Photophysical properties of trans-3-(4-monomethylamino-phenyl)-acrylonitrile: Evidence of twisted intramolecular charge transfer (TICT) process

“…The fluorescence decay of CT band (415 nm) band in acetonitrile solvent is 0.375 ns. The charge transfer excited state decays faster than the LE state [38,39]. The fluorescence decay in polar solvent like water is of different nature.…”

Solvent tuned single molecule dual emission in protic solvents: effect of polarity and H-bonding

“…In the present study, we assess the effect of protic solvents on the dual emission of Phen-PENMe 2 ( Figure 1). Such studies have been made on ICT molecules displaying pyrene, 13 stilbene, 14 9aminoacridine, 15,16 and imidazole 17 motifs as well as the 5-(4dimethylamino-phenyl)-penta-2,4-dienoic acid ethyl ester DMAPPDE compound. 18 In some of these cases, the contribution of a tautomerization (with an equilibrium being struck between ketoamine and enol-imine species) and an intramolecular H-bond render the problem more complex.…”

Modulação de fluorescência de amino coumarinas e acridinas por nanopartículas de prata

“…Os processos de transferência de carga são extensivamente estudados na literatura. Em um trabalho publicado recentemente [27], tais processos (ICT) foram observados em derivados de 9-aminoacridina.…”

“…Os derivados de 9-aminoacridina (figura 7) foram sintetizados em nosso grupo segundo procedimentos descritos na literatura [27,28]. Os corantes amino-coumarinas (C1, C151, C500) foram obtidas da Acros Organics, e a C120 da Sigma Co. Todos os álcoois foram secos em peneira molecular antes do uso.…”

“…Os três derivados de 9-aminoacridina também apresentaram decaimento biexponencial em solvente puro (2-propanol). Este comportamento é atribuído a uma interconversão entre um único estado excitado e o estado ICT [27,28]. A formação do estado ICT ocorre pela presença de grupos retiradores de elétrons como CN e CO, localizados nos substituintes aminovinílicos do fluoróforo 9-aminoacridina.…”