Proton transfer and hydrogen bonding in the internal conversion of S1 anthraquinones

Flom, Steven R.; Barbara, Paul F.

doi:10.1021/j100267a017

Cited by 206 publications

(148 citation statements)

References 3 publications

Supporting

Mentioning

135

Contrasting

Order By: Relevance

“…Indeed, an intramolecular hydrogen bond can be formed between the amino and carbonyl groups of KN. However, in previous reports on ESIPT-induced deactivation of methyl salicylate 22 and diaminoanthraquinone, 23,24 the fast fluorescence decay observed was solvent independent. The strong solvent dependence observed here with KN can be attributed to the disruption of the intramolecular hydrogen bonding in protic solvents, which thus inhibits ESIPT.…”

Section: Discussionmentioning

confidence: 62%

Ultrafast Excited-State Dynamics of Kynurenine, a UV Filter of the Human Eye

et al. 2009

View full text Add to dashboard Cite

The excited-state dynamics of kynurenine (KN) has been examined in various solvents by femtosecondresolved optical spectroscopy. The lifetime of the S 1 state of KN amounts to 30 ps in aqueous solutions, increases by more than 1 order of magnitude in alcohols, and exceeds 1 ns in aprotic solvents such as DMSO and DMF, internal conversion (IC) being shown to be the main deactivation channel. The IC rate constant is pH independent but increases with temperature with an activation energy of about 7 kJ/mol in all solvents studied. The dependence on the solvent proticity together with the observation of a substantial isotope effect indicates that hydrogen bonds are involved in the rapid nonradiative deactivation of KN in water. These results give new insight into the efficiency of KN as a UV filter and its role in cataractogenesis.

show abstract

Section: Discussionmentioning

confidence: 62%

Ultrafast Excited-State Dynamics of Kynurenine, a UV Filter of the Human Eye

et al. 2009

View full text Add to dashboard Cite

show abstract

“…13,[32][33][34][35][36][37][38][39] This process is enabled by the nitro groups of EB that are good hydrogen-bond acceptors. [24][25][26]40,41 In order to further confirm this hypothesis, TA measurements were carried out in perdeuterated water.…”

Section: Articlementioning

confidence: 99%

Ultrafast Excited-State Dynamics of Eosin B: A Potential Probe of the Hydrogen-Bonding Properties of the Environment

2011

View full text Add to dashboard Cite

The photophysics of two dyes from the xanthene family, eosin B (EB), and eosin Y (EY) has been investigated in various solvents by femtosecond transient absorption spectroscopy, first, to clarify the huge disparity of the EB fluorescence lifetimes reported in literature, and, second, to understand the mechanism responsible for the ultrafast excited-state deactivation of EB in water. The excited-state lifetime of EB was found to be much shorter in water and in other protic solvents, due to the occurrence of hydrogen-bond assisted nonradiative deactivation. This mechanism is associated with the hydrogen bonds between the solvent molecules and the nitro groups of EB, which become stronger upon optical excitation due to the charge-transfer character of the excited-state. This process is not operative with EY, where the nitro groups are replaced by bromine atoms. Therefore, the excited-state lifetime of EB in solution is directly related to the strength of the solvent as a hydrogen-bond donor, offering the possibility to build a corresponding scale based on the fluorescence quantum yield or lifetime of EB. This scale of hydrogen-bonding strength could be especially useful for studies of liquid interfaces by time-resolved surface second harmonic generation

show abstract

“…Since the original work of Forster (2) and Weller (3) on 1-naphthylamine-4-sulfonate, considerable research work on proton transfer has been done over the years (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Due to these efforts, the acid-base behavior of various substituent groups attached to aromatic moieties in both the So and S , electronic states is now well understood.…”

Section: Introductionmentioning

confidence: 99%

Proton transfer equilibrium reactions in some substituted 3H-indole probe molecules: role played by the TICT state

Sarpal¹,

Belletête²,

Durocher³

1993

Can. J. Chem.

View full text Add to dashboard Cite

(6). The dependence of absorption and fluorescence spectral characteristics upon acidity has allowed us to characterize four species, namely, the anion (A), the neutral molecule (N), the cation (C), and the dication (DC), for molecules 2 and 3 . Molecules 4, 5, and 6 give rise to an additional anion due to the hydrolysis of the ester group. The relative order of protonations to available sites is discussed. The ring-protonated species have shown the Ph, and indole rings to be coplanar in both the ground and first excited singlet states. A low-energy non-emissive twisted intramolecular charge transfer (TICT) state taking its origin in the dimethylamino moiety is suggested from INDO-S calculations to explain the strong fluorescence quenching of these ring-protonated species. Acidity constants for the various prototropic equilibria have been determined experimentally both in the ground and in the excited singlet states. Forster cycle calculations have been used to supplement the various equilibrium constants. Possible applications in organized assemblies are discussed. additionnel qui provient d'une hydrolyse de l'ester. On discute de I'ordre relatif des protonations des divers sites. On a dCmontrC que les espbces protonCes des cycles benzenique et indolique sont coplanaires tant dans 1'Ctat fondamental que dans le premier Ctat excitC. Sur la base de calculs INDO-S, on suggbre qu'un Ctat de transfert de charge intramolCculaire dCformC, de basse Cnergie, non radiatif et dont I'origine se trouverait dans la portion dimCthylamino peut expliquer la forte dksactivation de fluorescence de ces espbces protonkes sur le cycle. On a dCterminC experimentalement les constantes d'aciditt des divers Cquilibres prototropiques tant dans 1'Ctat fondamental que dans les Ctats excites. On a utilisC des calculs de cycles de Forster comme supplCments aux diverses constantes d'kquilibre. On discute de diverses applications possibles pour des systbmes organises.[Traduit par la rCdaction]

show abstract

Proton transfer and hydrogen bonding in the internal conversion of S1 anthraquinones

Cited by 206 publications

References 3 publications

Ultrafast Excited-State Dynamics of Kynurenine, a UV Filter of the Human Eye

Ultrafast Excited-State Dynamics of Kynurenine, a UV Filter of the Human Eye

Ultrafast Excited-State Dynamics of Eosin B: A Potential Probe of the Hydrogen-Bonding Properties of the Environment

Proton transfer equilibrium reactions in some substituted 3H-indole probe molecules: role played by the TICT state

Contact Info

Product

Resources

About