Has the Excited State Proton Transfer Ever Been Observed in Phenol−(NH3)n Molecular Clusters?

Grégoire, Gilles; Dedonder‐Lardeux, C.; Jouvet, Christophe; Martrenchard, and S.; Solgadi, D.

doi:10.1021/jp0046039

Cited by 54 publications

(48 citation statements)

References 65 publications

(209 reference statements)

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“…Because of the Coulomb attraction the phenolate anion and the NH ‡ 4 (NH3)n¡1 entities cannot separate from each other and cannot lead to the formation of free NH4(NH3)n entities. Experimentally, large NH ‡ 4 (NH3)n¡1 are not observed, whereas parent clusters with n up to 12 have been observed in the explansion (GreÂ goire et al 2001). …”

Section: Evidence For Ground State Proton Transfermentioning

confidence: 90%

Is there an Excited State Proton Transfer in phenol (or 1 -naphthol)-ammonia clusters? Hydrogen Detachment and Transfer to Solvent: A key for non-radiative processes in clusters

David¹,

Dedonder‐Lardeux²,

Jouvet³

2002

International Reviews in Physical Chemistry

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This contribution highlights recent advances in the understanding of excited state dynamics in aromatic enols. This review will be mainly focused on the experimental and theoretical work performed on two model systems, 1-naphthol± ammonia and phenol±ammonia, and most particularly on cluster studies. These systems have long been thought to be prototypes for the famous`solvent-induced excited state proton transfer reaction', but recent results contradict this mechanism. The dynamics of these systems, excited in the S1 (ºº*) state, is not governed by couplings with ion pair states, inducing intracluster proton transfer, but rather linked to a crossing with a higher excited singlet state of the º¼* Rydberg state character, dissociative along the OH coordinate, leading to a hydrogen transfer from the hydroxyl group to the ammonia cluster via a non-adiabatic process, a mechanism also referred to as`concerted electron and proton transfer'. The crossing of the higher 1 º¼* state with lower excited 1 ºº* and ground states seems to be a general property in aromatic enols and azines (indole derivatives) and can help to understand the non-radiative decays in amino acid molecules as well as in DNA bases.

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Section: Evidence For Ground State Proton Transfermentioning

confidence: 90%

Is there an Excited State Proton Transfer in phenol (or 1 -naphthol)-ammonia clusters? Hydrogen Detachment and Transfer to Solvent: A key for non-radiative processes in clusters

David¹,

Dedonder‐Lardeux²,

Jouvet³

2002

International Reviews in Physical Chemistry

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“…The ESHT reaction is contrary to the traditional view that this cluster system will undergo an excited state proton transfer (ESPT) reaction as the pKa of this weak acid is lowered in the electronically excited state. 3 However, the ESHT reaction has been computationally predicted and experimentally confirmed in many systems including phenol, [4][5][6][7] halogenated phenols, 8,9 methylphenol, 10 thiophenol, [11][12][13] pyrrole, 14 indole, 15 and 3-methyl-indole. 16 The ESHT reaction of phenol is driven by a πσ* state that is repulsive along the O-H bond.…”

Section: Introductionmentioning

confidence: 99%

Effects of Amino Substitution on the Excited State Hydrogen Transfer in Phenol: A TDDFT Study

2009

Bulletin of the Korean Chemical Society

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When isolated phenol or a small phenol-solvent cluster is excited to the S1 state of ππ* character, the hydrogen atom of the hydroxyl group dissociates via a πσ* state that is repulsive along the O-H bond. We computationally investigated the substitution effects of an amino group on the excited state hydrogen transfer reaction of phenol. The time-dependent density functional theory (TDDFT) with B3LYP functional was employed to calculate the potential energy profiles of the ππ* and the πσ* excited states along the O-H coordinate, together with the orbital shape at each point, as the position of the substituent was varied. It was found that the amino substitution has an effect of lowering the πσ* state and enhancing the excited state hydrogen transfer reaction.

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“…We trace the decrease of F back to an H atom transfer in the excited state, which forms the ammonium Rydberg radical. This mechanism has been proposed by Gregoire et al [4,21] based on the lifetimes of several phenol-ammonia clusters and their perdeuterated isotopomers.…”

Section: Discussionmentioning

confidence: 86%

“…by GrØgoire et al [4,21] The rotational constant of ammonia about its symmetry axis is 6.228 cm À1 , [22] while the rotational constant of the spherical rotor NH 4 C is 5.674 cm À1 , determined from a rotationally resolved photoelectron spectrum. [23] This difference between the rotational constants of NH 3 and NH 4 C is similar to the reduction of F, which we observe in the phenolammonia cluster upon electronic excitation.…”

Section: Phenol(nh 3 )mentioning

confidence: 99%

Torsional Barriers in Aromatic Molecular Clusters as Probe of the Electronic Properties of the Chromophore

Jacoby

Schmitt

2004

ChemPhysChem

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We present a computer program that is capable of fitting n-fold torsional barriers Vn (n = 2-6) and torsional constants F simultaneously to high- and low-resolution spectroscopic data of different isotopomeric internal rotors. The program has been utilized to fit independently barriers and torsional constants for both electronic states of several aromatic clusters. The constant F of the ammonia moiety in the phenol-ammonia cluster is shown to decrease upon electronic excitation, thus imaging the formation of a hydrogen-bonded complex between the phenoxy radical and the NH4 radical in the excited state. In contrast, for the naphthol-ammonia 1:1 clusters no change of F of ammonia could be found. For phenol-methanol cluster we found a decrease of F upon excitation which points to a stronger hydrogen bond between phenol and methanol in the excited state. A strong reduction of the torsional barrier upon excitation points to the formation of a methoxonium radical in a similar photoreaction as in phenol-ammonia cluster. For the phenol-water system we postulate the same mechanism, a photoreaction, which leads to a translocated hydrogen atom in the S1 state what can be deduced from the change of the torsional constant upon electronic excitation.

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Has the Excited State Proton Transfer Ever Been Observed in Phenol−(NH₃)_n Molecular Clusters?

Cited by 54 publications

References 65 publications

Is there an Excited State Proton Transfer in phenol (or 1 -naphthol)-ammonia clusters? Hydrogen Detachment and Transfer to Solvent: A key for non-radiative processes in clusters

Is there an Excited State Proton Transfer in phenol (or 1 -naphthol)-ammonia clusters? Hydrogen Detachment and Transfer to Solvent: A key for non-radiative processes in clusters

Effects of Amino Substitution on the Excited State Hydrogen Transfer in Phenol: A TDDFT Study

Torsional Barriers in Aromatic Molecular Clusters as Probe of the Electronic Properties of the Chromophore

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