Charge injected proton transfer in indigo derivatives

2021 ◽  
Vol 23 (38) ◽  
pp. 21972-21980
Author(s):  
Kazuho Ikeda ◽  
Dongho Yoo ◽  
Ryu Nishikawa ◽  
Tadashi Kawamoto ◽  
Takehiko Mori
Keyword(s):  
Proton Transfer ◽  
Organic Semiconductors ◽  
Intermolecular Proton Transfer ◽  
Donor And Acceptor ◽  
Hydrogen Bonded

The donor and acceptor abilities of hydrogen bonded organic semiconductors are significantly improved by intermolecular proton transfer.

Intermolecular proton transfer in catalysis by carbonic anhydrase V

1999 ◽  
Vol 77 (5-6) ◽  
pp. 726-732 ◽  
Author(s):  
J Nicole Earnhardt ◽  
Chingkuang Tu ◽  
David N Silverman
Keyword(s):  
Carbonic Anhydrase ◽  
Proton Transfer ◽  
Active Site ◽  
Rate Constants ◽  
Intramolecular Proton Transfer ◽  
Proton Donor ◽  
Marcus Theory ◽  
Intermolecular Proton Transfer ◽  
Donor And Acceptor ◽  
Active Site Cavity

The dehydration of bicarbonate catalyzed by carbonic anhydrase is accompanied by the transfer of a proton from solution to the zinc-bound hydroxide. We have investigated the properties of proton transfer from donors in solution, mostly derivatives of imidazole and pyridine, to a truncated mutant of carbonic anhydrase V with replacements that render the active site cavity less sterically constrained, Tyr 64 →> Ala and Phe 65 →> Ala. Catalysis was measured by determining the rate of exchange of 18O between the CO2-HCO3- system and water, and rate constants for proton transfer were estimated as the rate-limiting step in the release of H218O from the enzyme to solution. Each proton donor enhanced catalytic activity in a saturable manner. The resulting rate constants for proton transfer when compared with the values of pKa of the donor and acceptor gave a Brønsted plot of high curvature. These data could also be described by Marcus theory which showed an intrinsic barrier for intermolecular proton transfer near 0.8 kcal/mol and a work term or thermodynamic contribution to the free energy of reaction near 10 kcal/mol. This low intrinsic kinetic barrier for proton transfer is very similar to nonenzymic bimolecular proton transfer between nitrogen and oxygen acids and bases in solution. However, the significant thermodynamic contribution suggests appreciable involvement of solvent and active-site organization prior to proton transfer. These Marcus parameters are very similar to those describing intramolecular proton transfer from His 64 in carbonic anhydrase, suggesting similarities in the intra- and intermolecular proton transfer processes.Key words: carbonic anhydrase, proton transfer, Marcus theory, carbon dioxide.

Intermolecular proton transfer induced by excess electron attachment to adenine(formic acid)n (n=2, 3) hydrogen-bonded complexes

2007 ◽  
Vol 342 (1-3) ◽  
pp. 215-222 ◽  
Author(s):  
Kamil Mazurkiewicz ◽  
Maciej Haranczyk ◽  
Piotr Storoniak ◽  
Maciej Gutowski ◽  
Janusz Rak ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Formic Acid ◽  
Electron Attachment ◽  
Excess Electron ◽  
Intermolecular Proton Transfer ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Damaging Intermolecular Energy and Proton Transfer Processes in Alpha-Particle-Irradiated Hydrogen-Bonded Systems

2018 ◽  
Vol 130 (52) ◽  
pp. 17269-17273 ◽  
Author(s):  
Shenyue Xu ◽  
Dalong Guo ◽  
Xinwen Ma ◽  
Xiaolong Zhu ◽  
Wentian Feng ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Alpha Particle ◽  
Transfer Processes ◽  
Intermolecular Energy ◽  
Hydrogen Bonded Systems ◽  
Hydrogen Bonded

Excited-State Intramolecular Proton Transfer in Polymers

1995 ◽  
Vol 413 ◽  
Author(s):  
Richard M. Tarkka ◽  
Samson A. Jenekhe
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Main Chain ◽  
Intramolecular Proton Transfer ◽  
Polymer Structure ◽  
Laser Dyes ◽  
Excimer Formation ◽  
Photochromic Materials ◽  
Hydrogen Bonded

ABSTRACTExcited state intramolecular proton transfer (ESIPT) has been demonstrated in new intramoleculary hydrogen bonded (IHB) polymers of interest as photostabilizers, triplet quenchers, photochromic materials, laser dyes and electroluminescent materials. The new IHB polymers containing the 2-(2-hydroxyphenyl)benzoxazole moiety in the main chain were used to explore the effects of polymer structure, extended conjugation and competition with excimer formation on the ESIPT process. It was found that polymer structure, and particularly extent of conjugation, affects an IHB polymer's ability to exhibit ESIPT.

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