Dual fluorescence of 2-(4′-N,N-dimethylaminophenyl)pyrido[3,4-d]imidazole: effect of solvents

Krishnamoorthy, G.; Dogra, S. K.

doi:10.1016/s1386-1425(99)00059-1

Cited by 29 publications

(50 citation statements)

References 33 publications

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“…For some ESPT reactions, the structures of ground-state solutesolvent complexes are important (202), while for others they are not. We can even observe that for some excited-state isomerizations there is no excited-state equilibrium, despite the fact that all the species originate from the same ground-state precursor (203). Another source of ground-state heterogeneity is connected with the possibility of adsorption of the probe at a surface or interface with a steep gradient of polarity, such as phospholipid vesicles and biomembranes (175,176); the distribution of locations may provide a dramatic effect.…”

Section: How To Choose the Probe?mentioning

confidence: 96%

The red‐edge effects: 30 years of exploration

2002

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In 1970, three laboratories independently made a discovery that, for aromatic fluorophores embedded into different rigid and highly viscous media, the spectroscopic properties do not conform to classical rules. The fluorescence spectra can depend on excitation wavelength, and the excited-state energy transfer, if present, fails at the "red" excitation edge. These red-edge effects were related to the existence of excited-state distribution of fluorophores on their interaction energy with the environment and the slow rate of dielectric relaxation of this environment. In these conditions the site-selection can be provided by variation of the energy of illuminating light quanta, and the behaviour of selected species can be followed as a function of time and other variables. These observations found extensive application in different areas of research: colloid and polymer science, molecular biophysics, photochemistry and photobiology. In particular, they led to the development of very productive methods of studying the dynamics of dielectric relaxations in protein and membranes, using the tryptophan emission and the emission of a variety of probes. These studies were extended to the time domain with the observation of new site-selective effects in emission intensity and anisotropy decays. They stimulated the emergence and development of cryogenic energy-selective and single-molecular techniques that became valuable tools in their own right in chemistry and biophysics research. Site-selection effects were discovered for electron-transfer and proton-transfer reactions if they depended on the dynamics of the environment. This review is focused on the progress in the field of red-edge effects, their applications and prospects.

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Section: How To Choose the Probe?mentioning

confidence: 96%

The red‐edge effects: 30 years of exploration

2002

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“…Our studies (20)(21)(22)(23)(24) also indicated that the hydrogen bonding of the electron acceptor group with the solvent molecules and the dipole-dipole interactions stabilization of the electron donor group upon solvation are responsible for the formation and stabilization of the TICT state in DMAPPI. Besides the dual emission, the fluorescence quantum yield of the normal emission (φ N fl ) also undergoes drastic changes, i.e., φ N fl increases with an increase in the polarity and in the weak hydrogen-bonding solvents, but decreases from 0.76 in ethanol to 0.22 in methanol and to 0.11 in water.…”

Section: Methodsmentioning

confidence: 61%

“…Similar to protic solvents (20), the excitation spectra shifted toward red with increasing λ em , indicating the presence of different solvated molecules in the present system also. The excited state lifetimes of DMAPPI were measured in reverse micelles at different w 0 values by excitation at 332 nm and monitoring at 400 and 500 nm, respectively (Fig.…”

Section: Effect Of Watermentioning

confidence: 59%

“…Recently, we showed that 2-(4 -N,N-dimethylaminophenyl)pyrido [3,4-d]imidazole (DMAPPI) emits TICT in polar/ protic solvents (20). Our studies (20)(21)(22)(23)(24) also indicated that the hydrogen bonding of the electron acceptor group with the solvent molecules and the dipole-dipole interactions stabilization of the electron donor group upon solvation are responsible for the formation and stabilization of the TICT state in DMAPPI.…”

Section: Methodsmentioning

confidence: 99%

“…We have also studied the effect of the surfactant and cosurfacant concentration, pH, and trifluoroacetic acid (TFA). The results thus obtained have been compared with those obtained from the AM1 calculations (20,25).…”

Section: Methodsmentioning

confidence: 99%

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