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The keto→enol photoisomerization of N ‐salicilydenemethylfurylamine: Nonadiabatic ab initio dynamics simulation
Author(s) -
Gao Aihua,
Wang Meishan
Publication year - 2018
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25656
Subject(s) - photoisomerization , conical intersection , chemistry , isomerization , intramolecular force , enol , excited state , photochemistry , cis–trans isomerism , ab initio , molecule , hydrogen bond , photochromism , keto–enol tautomerism , computational chemistry , tautomer , stereochemistry , atomic physics , catalysis , physics , biochemistry , organic chemistry
The photoinduced isomerization of cis ‐keto and trans ‐keto isomers in N ‐salicilydenemethylfurylamine has been studied using the surface‐hopping approach at the CASSCF level of theory. After the cis ‐keto or trans ‐keto isomer is excited to S 1 state, the molecule initially moves to a excited‐state local minimum. The torsional motion around relative bonds in the chain drives the molecule to approach a keto‐form conical intersection and then nonadiabatic transition occurs. According to our full‐dimensional dynamics simulations, the trans ‐keto and enol photoproducts are responsible for the photochromic effect of cis ‐keto isomer excited to S 1 state, while no enol isomer was obtained in the photoisomerization of trans keto on excitation. The cis keto to enol and cis keto to trans keto isomerizations are reversible photochemical reactions. It is confirmed that this aromatic Schiff base is a potential molecular switch. Furthermore, the torsion of CN bond occurs in the radiationless decay of trans ‐keto isomer, while it is completely suppressed by an intramolecular hydrogen bonding interaction in the dynamics of cis ‐keto form. Moreover, the excited‐state lifetime of cis keto is longer than that of trans ‐keto form due to the O···HN hydrogen bond.