The present invention is a photochromic material formed of a biimidazole compound represented by general formula (1-1):
(where, R
4
and R
5
respectively and independently represent a halogen atom or alkyl group, R
1
to R
3
and R
6
to R
8
respectively and independently represent a hydrogen atom, halogen atom, alkyl group, fluoroalkyl group, hydroxyl group, alkoxyl group, amino group, alkylamino group, carbonyl group, alkylcarbonyl group, nitro group, cyano group or aryl group, Ar
1
to Ar
4
respectively and independently represent a substituted or unsubstituted aryl group, R
4
may form a condensed, substituted or unsubstituted aryl ring with R
3
, and R
5
may form a condensed, substituted or unsubstituted aryl ring with R
6
).
the photodecoloration reaction proceeds via a short-lived radical with a half-life of 9.4 μs in benzene at room temperature. Both the colored and colorless species show the photoinduced homolytic bond cleavage reaction of the C-N bond between the nitrogen atom of the imidazole ring and the carbon atom of the 1-position of the 1,1'-binaphthyl moiety and that of the C-C bond between each of the carbon
Nanosecond photochromic molecular switching of a biphenyl-bridged imidazole dimer revealed by wide range transient absorption spectroscopy
作者:Tetsuo Yamaguchi、Michiel F. Hilbers、Paul P. Reinders、Yoichi Kobayashi、Albert M. Brouwer、Jiro Abe
DOI:10.1039/c4cc06001f
日期:——
We demonstrate that a biphenyl-bridged imidazole dimer exhibits fast photochromism with a thermal recovery time constant of ∼100 ns, which is the fastest thermal back reaction in all reported imidazole dimers.