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Rational design of a new class of diffusion‐inhibited HABI with fast back‐reaction
Author(s) -
Iwahori Fumiyasu,
Hatano Sayaka,
Abe Jiro
Publication year - 2007
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1183
Subject(s) - chemistry , naphthalene , photochromism , photochemistry , radical , activation energy , kinetics , irradiation , organic chemistry , physics , quantum mechanics , nuclear physics
The fast reversible photochromic molecule was synthesized with the aid of triphenylimidazolyl radicals (TPI ˙ ) and naphthalene linker. The crystal structure, photochemical properties, and kinetics of the target compound (1,8‐TPID‐naphthalene) were investigated. 1,8‐TPID‐naphthalene photochemically cleaved into 1,8‐bisTPI ˙ ‐ naphthalene and the color of the solution changed from colorless to green. ESR spectroscopy detected the light‐induced triplet radical pair in frozen matrix. After the UV irradiation is ceased, the back‐reaction of 1,8‐bisTPI ˙ ‐naphthalene occurred by thermal conversion in the dark. The kinetic study on the back‐reaction revealed that the reaction obeys the first‐order kinetics with 2.04 s of half‐life time at 295 K. The activation energy and frequency factor of the back‐reaction were determined as 42.0 kJ/mol and 9.25 × 10 6 s −1 , respectively. Copyright © 2007 John Wiley & Sons, Ltd.