Role of Solvent in Excited-State Proton Transfer in Hypericin

1994 ◽  
Vol 98 (34) ◽  
pp. 8352-8358 ◽  
Author(s):  
F. Gai ◽  
M. J. Fehr ◽  
J. W. Petrich
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Excited State Proton Transfer ◽  
Role Of Solvent

scholarly journals Revealing the role of excited state proton transfer (ESPT) in excited state hydrogen transfer (ESHT): systematic study in phenol–(NH3)n clusters

2021 ◽  
Author(s):  
Christophe Jouvet ◽  
Mitsuhiko Miyazaki ◽  
Masaaki Fujii
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Systematic Study ◽  
General Model ◽  
Hydrogen Transfer ◽  
Excited State Proton Transfer

A general model of excited state hydrogen transfer (ESHT) which unifies ESHT and the excited state proton transfer (ESPT) is presented from experimental and theoretical works on phenol–(NH3)n. The hidden role of ESPT is revealed.

Excited-State Proton Transfer: Molecules in a Hurry to Get Rid of Antiaromaticity

2019 ◽  
Author(s):  
Chia-Hua Wu ◽  
Lucas Karas ◽  
Henrik Ottosson ◽  
Judy Wu
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Chemical Shifts ◽  
Proton Relay ◽  
Proton Transfers ◽  
Bifunctional Compounds ◽  
Excited State Proton Transfer ◽  
Derivatives Of ◽  
Related Compounds

<p>Baird’s rule explains why and when excited-state proton transfer (ESPT) reactions happen in organic compounds. Bifunctional compounds that are [4<i>n</i>+2] π-aromatic in the ground state, become [4<i>n</i>+2] π-antiaromatic in the first <sup>1</sup>ππ* states, and proton transfer (either<i>inter-</i>or <i>intra-</i>molecularly) helps relieve excited-state antiaromaticity. Computed nucleus independent chemical shifts (NICS) for several ESPT examples (including excited-state intramolecular proton transfers (ESIPT), biprotonic transfers, dynamic catalyzed transfers, and proton relay transfers) document the important role of excited-state antiaromaticity. <i>o-</i>Salicylic acid undergoes ESPT only in the “antiaromatic” S<sub>1</sub>(<sup>1</sup>ππ*) state, but not in the “aromatic” S<sub>2</sub>(<sup>1</sup>ππ*) state. Stokes’ shifts of structurally-related compounds (<i>e.g.</i>, derivatives of 2-(2-hydroxyphenyl)benzoxazole and hydrogen-bonded complexes of 2-aminopyridine with pro tic substrates) vary depending on the antiaromaticity of the photoinduced tautomers. Remarkably, Baird’s rule predicts the effect of light on hydrogen bond strengths; hydrogen bonds that enhance (and reduce) excited-state antiaromaticity in compounds become weakened (and strengthened) upon photoexcitation.</p>

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