Non-exponential solvation dynamics of electronically excited 4-aminophthalimide in n-alcohols

Harju, Timo; Huizer, A. Herbert; Varma, Cyril A. G. O.

doi:10.1016/0301-0104(95)00214-9

Cited by 54 publications

(71 citation statements)

References 33 publications

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“…[14d, 45,46,69] The nonexponentiality of the solvent relaxation function has been attributed to the molecular motion of the solvent molecules, such as hydroxyl rotations, in the proximity of the solute molecule, which cannot be predicted using bulk dielectric data of the neat solvent and the dielectric continuum theory. Unfortunately, in the present investigation, although we observe the wavelength-dependent temporal dynamics of SE, which clearly reveal the solvent reorganization process, the time correlation function for the dynamic shift of the SE maximum [i.e, C(t)] could not be measured with reasonable accuracy for several reasons, as mentioned earlier.…”

Section: Dynamics Of the Hydrogen Bondmentioning

confidence: 99%

The Role of Hydrogen‐Bonding Interactions in the Ultrafast Relaxation Dynamics of the Excited States of 3‐ and 4‐Aminofluoren‐9‐ones

et al. 2009

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The dynamics of the excited states of 3- and 4-aminofluoren-9-ones (3AF and 4AF, respectively) are investigated in different kinds of solvents by using a subpicosecond time-resolved absorption spectroscopic technique. They undergo hydrogen-bonding interaction with protic solvents in both the ground and excited states. However, this interaction is more significant in the lowest excited singlet (S(1)) state because of its substantial intramolecular charge-transfer character. Significant differences in the spectroscopic characteristics and temporal dynamics of the S(1) states of 3AF and 4AF in aprotic and protic solvents reveal that the intermolecular hydrogen-bonding interaction between the S(1) state and protic solvents plays an important role in its relaxation process. Perfect linear correlation between the relaxation times of the S(1) state and the longitudinal relaxation times (tau(L)) of alcoholic solvents confirms the prediction regarding the solvation process via hydrogen-bond reorganization. In the case of weakly interacting systems, the relaxation process can be well described by a dipolar solvation-like process involving rotation of the OH groups of the alcoholic solvents, whereas in solvents having a strong hydrogen-bond-donating ability, for example, methanol and trifluoroethanol, it involves the conversion of the non-hydrogen-bonded form to the hydrogen-bonded complex of the S(1) state. Efficient radiationless deactivation of the S(1) state of the aminofluorenones by protic solvents is successfully explained by the energy-gap law, by using the energy of the fully solvated S(1) state determined from the time-resolved spectroscopic data.

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Section: Dynamics Of the Hydrogen Bondmentioning

confidence: 99%

The Role of Hydrogen‐Bonding Interactions in the Ultrafast Relaxation Dynamics of the Excited States of 3‐ and 4‐Aminofluoren‐9‐ones

et al. 2009

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“…The expected relationship between S and has been experimentally verified for NATA in propylene glycol over a range of temperatures (79) and for a variety of fluorophores and solvents (80)(81)(82)(83)(84). For NATA in propylene glycol (Fig.…”

Section: Timescales Of Dipolar Relaxation and Larger Molecular Motionsmentioning

confidence: 65%

On Spectral Relaxation in Proteins†¶‖

Lakowicz

2007

Photochemistry and Photobiology

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During the past several years there has been debate about the origins of nonexponential intensity decays of intrinsic tryptophan (trp) fluorescence of proteins, especially for single tryptophan proteins (STP). In this review we summarize the data from diverse sources suggesting that time‐dependent spectral relaxation is a ubiquitous feature of protein fluorescence. For most proteins, the observations from numerous laboratories have shown that for trp residues in proteins (1) the mean decay times increase with increasing observation wavelength; (2) decay associated spectra generally show longer decay times for the longer wavelength components; and (3) collisional quenching of proteins usually results in emission spectral shifts to shorter wavelengths. Additional evidence for spectral relaxation comes from the time‐resolved emission spectra that usually shows time‐dependent shifts to longer wavelengths. These overall observations are consistent with spectral relaxation in proteins occurring on a subnanosecond timescale. These results suggest that spectral relaxation is a significant if not dominant source of nonexponential decay in STP, and should be considered in any interpretation of nonexponential decay of intrinsic protein fluorescence.

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“…They also recorded a small bathochromic shift of the 4-AP absorption spectra in the above-mentioned solvents with decreasing temperature, thus an effect similar to that observed by us for C153 [11] and C102 [12]. Harju et al [17] have performed an extensive room temperature study of 4-AP fluorescence kinetics and TDSS in 13 n-alcohols with a 5 ps time-resolution. At this time-resolution they found that each kinetics is of multi-exponential character, which is a manifestation of the TDSS of 4-AP fluorescence in these solvents.…”

Section: Introductionmentioning

confidence: 73%