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Theoretical Study on the Substituent Effect on the Excited‐State Proton Transfer in the 7‐Azaindole‐Water Derivatives
Author(s) -
Yi Jiacheng,
Fang Hua
Publication year - 2017
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12839
Subject(s) - substituent , chemistry , excited state , halogen , proton , hydrogen atom , electronegativity , proton coupled electron transfer , atom (system on chip) , photochemistry , pyrrole , ring (chemistry) , computational chemistry , stereochemistry , electron transfer , atomic physics , organic chemistry , alkyl , physics , quantum mechanics , computer science , embedded system
The first excited‐state proton transfer ( ESPT ) in 7 AI ‐H 2 O complex and its derivatives, in which the hydrogen atom at the C 2 position in pyrrole ring was replaced by halogen atom X (X = F, Cl, Br), were studied at the TD ‐M06‐2X/6‐31 + G(d, p) level. The double proton transfer took place in a concerted but asynchronous protolysis pathway. The vibrational‐mode selectivity of excited‐state double proton transfer in the model system was confirmed. The specific vibrational‐mode could shorten the reaction path and accelerate the reaction rate. The substituent effects on the excited‐state proton transfer process were discussed. When the H atom at C 2 position in 7 AI ‐H 2 O complex was replaced by halogen atom, some geometrical parameters changed obviously, the barrier height of ESDPT reduced, and the asynchronicity of proton transfer enlarged. The above changes correlated with the Pauling electronegativity of halogen atom.