INVESTIGADORES
FALCONE Ruben Dario
artículos
Título:
Characterization of Multifunctional Reverse Micelles Interfaces Using Hemicyanines as Molecular Probes. II: Effect of the Surfactant
Autor/es:
SILVINA S. QUINTANA; FERNANDO MOYANO; R. DARÍO FALCONE; JUANA J. SILBER; N. MARIANO CORREA
Revista:
JOURNAL OF PHYSICAL CHEMISTRY B
Editorial:
American Chemical Society
Referencias:
Año: 2009 vol. 113 p. 6718 - 6724
ISSN:
1089-5647
Resumen:
In this work, we have investigated the behavior of the cationic hemicyanine trans-4-[4-(dimethylamino)-
styryl]-N-methylpyridinium iodide (HC) in benzene/benzyl-n-hexadecyl dimethylammonium chloride (BHDC)/
water reverse micelle media using absorption and emission spectroscopy in addition to the steady-state and
time-resolved fluorescence emission techniques and compare the results to those obtained in benzene/sodium
1,4-bis-2-ethylhexylsulfosuccinate (AOT)/water reverse micelle media (Moyano, F.; et al. J. Phys. Chem. Btrans-4-[4-(dimethylamino)-
styryl]-N-methylpyridinium iodide (HC) in benzene/benzyl-n-hexadecyl dimethylammonium chloride (BHDC)/
water reverse micelle media using absorption and emission spectroscopy in addition to the steady-state and
time-resolved fluorescence emission techniques and compare the results to those obtained in benzene/sodium
1,4-bis-2-ethylhexylsulfosuccinate (AOT)/water reverse micelle media (Moyano, F.; et al. J. Phys. Chem. BN-methylpyridinium iodide (HC) in benzene/benzyl-n-hexadecyl dimethylammonium chloride (BHDC)/
water reverse micelle media using absorption and emission spectroscopy in addition to the steady-state and
time-resolved fluorescence emission techniques and compare the results to those obtained in benzene/sodium
1,4-bis-2-ethylhexylsulfosuccinate (AOT)/water reverse micelle media (Moyano, F.; et al. J. Phys. Chem. BJ. Phys. Chem. B
2009, 113, 4284.) in order to gain more insight about reverse micelle interface properties. Our results show
that HC spectroscopic behavior is completely different when dissolved in AOT or in BHDC reverse micelle
media. While the dye experiences an intramolecular charge-transfer process upon excitation in the former
media, in BHDC, this process is inhibited because of the cationic nature of the surfactant. Interestingly, we
also show that the water properties are different for water molecules sequestrated inside of an anionic and
cationic reverse micelle system. This come out because the water molecules entrapped inside of the BHDC
reverse micelle media appear to be non-electron-donating because of its interaction with the cationic surfactant
polar head group. On the other hand, the water molecules sequestrated inside of the AOT reverse micelle
systems show its electron-donor ability enhanced in comparison with its water bulk structure. These results
could also explain the lack of nucleophilicity shown by the water molecules entrapped in BHDC reverse
micelle media reported in previous kinetic studies., 113, 4284.) in order to gain more insight about reverse micelle interface properties. Our results show
that HC spectroscopic behavior is completely different when dissolved in AOT or in BHDC reverse micelle
media. While the dye experiences an intramolecular charge-transfer process upon excitation in the former
media, in BHDC, this process is inhibited because of the cationic nature of the surfactant. Interestingly, we
also show that the water properties are different for water molecules sequestrated inside of an anionic and
cationic reverse micelle system. This come out because the water molecules entrapped inside of the BHDC
reverse micelle media appear to be non-electron-donating because of its interaction with the cationic surfactant
polar head group. On the other hand, the water molecules sequestrated inside of the AOT reverse micelle
systems show its electron-donor ability enhanced in comparison with its water bulk structure. These results
could also explain the lack of nucleophilicity shown by the water molecules entrapped in BHDC reverse
micelle media reported in previous kinetic studies.