The Dynamics of Polar Solvation

Castner, Edward W.; Bagchi, Biman; Maroncelli, Mark; Webb, S. P.; Ruggiero, Anthony J.; Fleming, Graham R.

doi:10.1002/bbpc.198800075

Cited by 105 publications

(42 citation statements)

References 49 publications

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“…These results are similar to other reports of solvent relaxation about excited chromophores in alcohols (32,33,36,41,42,50,53,54). Biphasic relaxation kinetics are typically observed, and one relaxation time is generally comparable to Tl1.…”

Section: Ru(bpy)2(cn)2supporting

confidence: 92%

Solvent Reorganization Energetics and Dynamics in Charge-Transfer Processes of Transition Metal Complexes

Zhang

Kozik

Sutin

et al. 1991

Advances in Chemistry

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Time-resolved and steady-state luminescence measurements were used to probe the energetics and dynamics of solvation in two different transition metal complexes. The metal-to-ligand charge-transfer excited state of Ru(bpy)2(CN)2 (bpy is bipyridine) was studied in a series of aliphatic alcohols, and the luminescent excited state of Mo2Cl4[P(CH3)3]4 was studied in aprotic organic solvents. The energetics of excited-state solvation were evaluated from the shapes and positions of the steady-state luminescence spectra recorded at low (~10 K) and room temperatures. The dynamics of excited-state solvation were probed by time-resolved emission spectroscopy. THE SOLVENT PLAYS A MAJOR ROLE I N GOVERNI NGthe rates of electrontransfer reactions in solution (I, 2). The solvent reorganization associated with electron-transfer reactions in polar solvents is often the major contributor to the total reorganization energy (X). In recent years, questions have arisen regarding the importance of solvent reorganization dynamics in controlling the rates of fast electron-transfer processes (3-11). Models that treat the solvent as a continuous dielectric medium are often used to describe solvation energetics and dynamics, but the applicability of these models to real chemical systems remains an open question. Electronic absorption and emission spectroscopies are powerful techniques for probing the environments of molecules in solution (12-22). The energies and shapes of absorption

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Section: Ru(bpy)2(cn)2supporting

confidence: 92%

Solvent Reorganization Energetics and Dynamics in Charge-Transfer Processes of Transition Metal Complexes

Zhang

Kozik

Sutin

et al. 1991

Advances in Chemistry

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“…8,9,11,12,14 The spectrum of the completely solvated anion was similar in all primary alcohols; however in secondary alcohols, the spectrum of the solvated anion is considerably red-shifted from that in primary alcohols. 21,22 This complexity has made it difficult to understand what physical processes in the alcohol will dominate the solvation process. They are also desirable because they can mimic some of the characteristics of water solvation but with slower solvation processes.…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature on the Dynamics of Benzophenone Anion Solvation in Alcohol

Zhang

1996

J. Phys. Chem.

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The solvation of the benzophenone anion in 1-propanol, 2-propanol, and 1-butanol has been measured over the temperature range -10 to -50°C. The initial spectra of the benzophenone anion were very similar in all three alcohols. The final spectrum of the benzophenone anion in 2-propanol is less blue-shifted (17 nm) than the spectrum of the anion in 1-propanol and 1-butanol. The activation energies for solvation are 22 kJ/mol for 1 propanol and 1-butanol and 16 kJ/mol for 2-propanol, which are similar to the energy for hydrogen bond breakage in the pure solvents. This suggests that the solvent H-bond

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“…These results resemble the vibrational frequencies observed in the condensed aromatic hydrocarbons containing more than two rings and this vibrational frequency corresponds to the frequency of the dominant C-C vibrational modes (37 the fluorescence band maxima and the fluorescence quantum yields observed in MPNI in all the solvents are independent of wavelength of excitation. This clearly indicates that the fluorescence is occurring from the most relaxed state in all the solvents and the solvent relaxation time is much smaller than the radiative lifetime as observed in other cases (38,39). The fluorescence excitation spectra recorded at different emission wavelengths are similar to each other as well as to the absorption spectra.…”

Section: Effect Of Solvents On the Spectral Characteristicsmentioning

confidence: 51%

Excited state intramolecular proton transfer in 2-(2'-hydroxyphenyl)-1H-naphth-[2,3-d]-imidazole: effects of solvents and pH

Das¹,

Krishnamoorthy²,

Dogra³

2000

Can. J. Chem.

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The solvent dependent study of absorption, fluorescence, and fluorescence excitation spectra of 2-(2 ′-hydroxyphenyl)-1H-naphth-[2,3-d]-imidazole (HPNI) have indicated the presence of different rotamers and tautomers in the S o and S 1 states. Similarity of the absorption and fluorescence spectra of HPNI in protic solvents with those of 2-(2 ′-methoxyphenyl)-1H-naphth-[2,3-d]-imidazole (MPNI) suggests that the normal emission is observed from the rotamers 2 and 4, whereas the tautomer emission is observed from the tautomer 3, formed by the excited state intramolecular proton transfer (ESIPT) in the rotamer 1 (Scheme 1). Ground state geometries of rotamers 1, 2, and the tautomer 3 were optimized using AM1 method. The results show that the rotamer 2 is the most stable and its stability further increases in polar and protic solvents due to the dipolar solvation interaction. The increase in the fluorescence quantum yield of the normal band when methanol or water is added to dioxane is due to: (i) the formation of rotamer 4, where ESIPT is not possible and (ii) the decrease in the rate of non-radiative decay process. Very large red shifted fluorescence bands of the monocations of HPNI and MPNI in different solvents have been assigned to the charge transfer band. Key words: 2-(2 ′-hydroxyphenyl)-1H-naphth-[2,3-d]-imidazole, ESIPT, prototropic reactions, fluorescence, 2-(2 ′-methoxyphenyl)-1H-naphth-[2,3-d]-imidazole. Résumé : L'influence du solvant sur les spectres d'absorption, de fluorescence et d'excitation de fluorescence du 2-(2-hydroxyphényl)-1H-napht-[2,3-d]-imidazole (HPNI) suggère la présence de divers rotamères et tautomères dans les états S 0 et S 1 . Les similarités entre les spectres d'absorption et de fluorescence du HPNI dans les solvants protiques et ceux du 2-(2-méthoxyphényl)-1H-naph-[2,3-d]-imidazole (MPNI) suggèrent que l'émission normale est observée à partir des rotamères 2 et alors que l'on observe l'émission tautomère à partir du tautomère 3 qui se forme par un transfert intramoléculaire de proton dans l'état excité (TIPEE) du rotamère 1 ( Schéma 1). Les géométries des rotamères 1 et 2 et du tautomère 3 dans leur état fondamental ont été optimisées à l'aide de la méthode AM1. Les résultats montrent que le rotamère 2 est le plus stable que sa stabilité est accrue par les solvants polaires et protiques en raison de l'interaction de solvatation dipolaire. L'augmentation du rendement quantique de fluorescence de la bande normale par addition de méthanol ou d'eau au dioxane résulte de: (i) la formation du rotamère 4 dans les cas où le TIPEE n'est pas possible; et (ii) de la diminution de la vitesse du processus de décroissance non radiative. Les importants déplacements vers le rouge des bandes de fluorescence des monocations du HPNI et du MPNI dans différents solvants ont été attribués à la bande de transfert de charge. Mots clés : 2-(2-hydroxyphényl)-1H-napht-[2,3-d]-imidazole, TIPEE, réactions prototropiques, fluorescence, 2-(2-méthoxyphényl)-1H-naph-[2,3-d]-imidazole. [Traduit par la Rédaction] Da...

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The Dynamics of Polar Solvation

Cited by 105 publications

References 49 publications

Solvent Reorganization Energetics and Dynamics in Charge-Transfer Processes of Transition Metal Complexes

Solvent Reorganization Energetics and Dynamics in Charge-Transfer Processes of Transition Metal Complexes

Effect of Temperature on the Dynamics of Benzophenone Anion Solvation in Alcohol

Excited state intramolecular proton transfer in 2-(2'-hydroxyphenyl)-1H-naphth-[2,3-d]-imidazole: effects of solvents and pH

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