Excited state dissociation rate constants in naphthols

Rosenberg, Jerome L.; Brinn, Ira M.

doi:10.1021/j100668a008

Cited by 51 publications

(26 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In comparison, the half a volt more positive redox potentials of naphthol (E 1/2 0/− * ≈0.9 V vs. SCE) makes PET from the amines to naphthol an unfavorable, endergonic process. In contrast, as can be seen in the relative p K a diagram in Figure b, the excited state acidity of naphthol (p K a *=2.85) is more than sufficient to protonate primary (p K a =10.4–10.6), secondary (p K a =10.0–11.2), and tertiary amines (p K a =9.8–10.6) . As far as we know the redox potentials and p K a * for BINOL have not been reported but we anticipate that they will be similar to naphthol, if not less easily reduced due to the increased conjugation.…”

Section: Enantioselective Sensingmentioning

confidence: 99%

Chirality and Excited State Proton Transfer: From Sensing to Asymmetric Synthesis

Posey

Hanson

2019

ChemPhotoChem

View full text Add to dashboard Cite

proton transfer (ESPT) is a unique photochemical process where the electron density shift of a molecule in the excited state dramatically decreases the pK a value of a proton donor site. A majority of ESPT research to date has focused on achiral molecules but there is growing interest in understanding/harnessing ESPT to/from chiral molecules. This review summarizes and critically examines the literature to date describing the role of ESPT in enantioselective fluorescence sensing, asymmetric synthetic organic chemistry, and photoisomerization of chiral molecules. Our goal is to show that despite ESPT of chiral molecules being a relatively new pursuit, there has been significant progress and even greater potential for ESPT in these and other applications yet to be realized.[a] V.

show abstract

Section: Enantioselective Sensingmentioning

confidence: 99%

Chirality and Excited State Proton Transfer: From Sensing to Asymmetric Synthesis

Posey

Hanson

2019

ChemPhotoChem

View full text Add to dashboard Cite

show abstract

“…This is also consistent with the fact that molecules including an aromatic ring are more acidic in the excited state than in the ground state. [62][63][64][65] Subsequently, the non-aromatic five-membered ring in 25 spontaneously tautomerizes to the fully aromatic indole system of 4-methoxy-5-nitro-7-nitrosoindole (26). The reaction mechanism for MDNI-Ac is outlined in Scheme 3.…”

mentioning

confidence: 99%

Competition Between Cyclization and Unusual Norrish Type I and Type II Nitro-Acyl Migration Pathways in the Photouncaging of 1-Acyl-7-nitroindoline Revealed by Computations

Morgante¹,

Guruge²,

Ouedraogo³

et al. 2020

Preprint

View full text Add to dashboard Cite

The 7-nitroindolinyl family of caging chromophores has received much attention in the past two decades. However, its uncaging mechanism is still not clearly understood. In this study, we performed state-of-the-art density functional theory calculations to unravel the photo-uncaging mechanism in its entirety, and we compared the probabilities of all plausible pathways. We found competition between a classical cyclization and acyl migration pathways, and here we explain the electronic and steric reasons behind such competition. The migration mechanism possesses the characteristics of a combined Norrish Type I and a 1,6-nitro-acyl variation of a Norrish Type II mechanism, which is reported here for the first time. We also introduced a computational procedure that allows the estimation of intersystem crossing rate constants useful to compare the relative quantum yield of substituted cages. This procedure may pave the way for improved cage designs that possess higher quantum yields and a more efficient agonist release.<br>

show abstract

“…This is also consistent with the fact that molecules including an aromatic ring are more acidic in the excited state than in the ground state. [66][67][68][69] Subsequently, the non-aromatic five-membered ring in 19 spontaneously tautomerizes to the fully aromatic indole system of 4-methoxy-5-nitro-7-nitrosoindole (8). The reaction mechanism for MDNI-Ac is outlined in Scheme 3.…”

Section: Figurementioning

confidence: 99%

Unusual Norrish Type I and Type II Nitro-Acyl Migration Transition State in the Photo-Uncaging of 1-Acyl-7-Nitroindolines Revealed by Computations

Morgante¹,

Guruge²,

Ouedraogo³

et al. 2020

Preprint

View full text Add to dashboard Cite

The 7-nitroindolinyl family of caging chromophores has received a lot of attention in the past two decades. However, it is not clear if they undergo cyclization or migration upon photo-uncaging to release the active compound. In this study, we performed state-of-the-art density functional theory calculations to fully understand the photo-uncaging mechanism and we compared the probabilities of all plausible pathways. We found that the key transition state in the lowest¬ energy pathway involves an acyl migration. It possesses the characteristics of a combined Norrish Type I and a 1,6-nitro-acyl variation of a Norrish Type II mechanism, which has not been previously reported. We also introduced a new computational procedure that allows the estimation of intersystem crossing rate constants useful to compare the relative quantum yield of substituted cages. This procedure may pave the way for improved cage designs that possess higher quantum yields and more efficient agonist release.<br><br>

show abstract

Excited state dissociation rate constants in naphthols

Abstract: Experimentally determined proton dissociation (and reassociation) rate constants for substituted naphthols in the first excited singlet state are reported. The results are rationalized on the basis of a charge-transfer explanation supported by CNDO/2 and PPP molecular orbital calculations.

Cited by 51 publications

References 1 publication

Chirality and Excited State Proton Transfer: From Sensing to Asymmetric Synthesis

Chirality and Excited State Proton Transfer: From Sensing to Asymmetric Synthesis

Competition Between Cyclization and Unusual Norrish Type I and Type II Nitro-Acyl Migration Pathways in the Photouncaging of 1-Acyl-7-nitroindoline Revealed by Computations

Unusual Norrish Type I and Type II Nitro-Acyl Migration Transition State in the Photo-Uncaging of 1-Acyl-7-Nitroindolines Revealed by Computations

Contact Info

Product

Resources

About