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Computational studies on electron and proton transfer in phenol‐imidazole‐base triads
Author(s) -
Yan Shihai,
Kang Sunwoo,
Hayashi Tomoyuki,
Mukamel Shaul,
Lee Jin Yong
Publication year - 2009
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21339
Subject(s) - imidazole , chemistry , hydrogen bond , proton , electron transfer , delocalized electron , phenol , base (topology) , solvent , density functional theory , photochemistry , molecule , computational chemistry , stereochemistry , organic chemistry , mathematical analysis , physics , mathematics , quantum mechanics
Abstract The electron and proton transfer in phenol‐imidazole‐base systems (base = NH 2 − or OH − ) were investigated by density‐functional theory calculations. In particular, the role of bridge imidazole on the electron and proton transfer was discussed in comparison with the phenol‐base systems (base = imidazole, H 2 O, NH 3 , OH − , and NH 2 − ). In the gas phase phenol‐imidazole‐base system, the hydrogen bonding between the phenol and the imidazole is classified as short strong hydrogen bonding, whereas that between the imidazole and the base is a conventional hydrogen bonding. The n value in sp n hybridization of the oxygen and carbon atoms of the phenolic CO sigma bond was found to be closely related to the CO bond length. From the potential energy surfaces without and with zero point energy correction, it can be concluded that the separated electron and proton transfer mechanism is suitable for the gas‐phase phenol‐imidazole‐base triads, in which the low‐barrier hydrogen bond is found and the delocalized phenolic proton can move freely in the single‐well potential. For the gas‐phase oxidized systems and all of the triads in water solvent, the homogeneous proton‐coupled electron transfer mechanism prevails. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010