Journal of the American Chemical Society p. 189 - 198 (1988)
Update date:2022-07-31
Topics: Photoisomerization Regioselective Experimental m-Styrylstilbenes Trans-Cis Photoisomerization
Ito, Yoshikatsu
Uozu, Yoshihiro
Dote, Toshimichi
Ueda, Masahiro
Matsuura, Teruo
Trans-cis photoisomerization of m-styrylstilbenes, i.e., 2,4,6-triisopropyl-3'-styrylstilbene (TISS), 2,4,6-trimethyl-3'-styrylstilbene (TMSS), and 3-styrylstilbene (SS), and of stilbenes, i.e., 2,4,6-triisopropylstilbene (TIS), 2,4,6-trimethylstilbene (TMS), and stilbene (S), are studied under direct or benzophenon-sensitized irradiation in hexane.Measurements of quantum yields for isomerization have revealed that although the styrylstilbene molecule bears two styryl groups, the reaction is highly regioselective, depending upon the excitation conditions and reactant structures.For example, isomerizations of trans,trans-TISS and trans,cis-TISS occured either at the 2,4,6-trisubstituted styryl side upon direct excitation or at the unsubstituted styryl side upon sensitized excitation.When the starting material carries an unsubstituted cis-styryl group, the major isomerization always occurred at this moiety by either direct or sensitized axcitation, e.g., cis,trans-TISS ---> trans,trans-TISS, cis,cis-TISS ---> trans,cis-TISS, and cis,trans-SS ---> trans,trans-SS.Furthermore, the photoisomerization of cis-SS was found to be one-way.These results are interpreted in terms of the usual "energy sink" concept: the excited-state energies (ES and ET) of the stilbene chromophores depend on molecular distortion in a subtle manner.It seems that an extremely rapid cis ---> trans isomerization rate of the unsubstituted cis-styryl group is also responsible for the observed preferential photoisomerization of this group.Finally, the cis,cis isomers of TISS, TMSS, and SS underwent upon sensitized excitation minor but substantial one-photon two-double-bond isomerization (cis,cis ---> trans,trans) in addition to major one-double-bond isomerization.This reaction is not common, since the two isomerizing double bonds are cross-conjugated.
View MoreQingdao S. H. Huanyu Imp. & Exp. Co., Ltd.
Contact:86-532-88250866
Address:Room 615, World Trade Centre Building B, Hongkong Middle Roda 6#, Qingdao, Shandong, China
Contact:+86-575-82733999 0575-82732999
Address:hangzhou gulf fine chemical zone,shangyu city,zhejiang province
HAINAN JINYING IMPORT AND EXPORT CO. LTD
Contact:+86-898-32875423
Address:A SECTION 19TH FL, TIMES SQUARE, NO.2 GUO MAO AVENUE HAIKOU, HAINAN, P. R. OF CHINA
LianYunGang Chiral Chemical(CHINA) CO.,LTD
Contact:+86-518-83616958 +86-519-82884848
Address:LianYunGang Chemical Industry Park (JiangSu)
Xi'an Costrong Pharmaceutical Co., Ltd.
Contact:029- 68576496
Address:Room 2004,Shuibao Building,No.190,South Erhuan Rd, Yanta District,Xi'an,Shaan Xi,China
Doi:10.1055/s-1986-31847
(1986)Doi:10.1016/j.ejmech.2008.02.007
(2009)Doi:10.1007/s11426-013-5042-2
(2014)Doi:10.1021/ja00345a001
(1983)Doi:10.1055/s-2005-870012
(2005)Doi:10.1039/c39820001260
(1982)