Photochromism of novel [1]benzothien-2-yl fulgides. Issue 38 (22nd September 2016)

• Record Type: Journal Article
• Authors: Zmeeva, Sofiya Yu.; Rybalkin, Vladimir P.; Popova, Lidiya L.; Tkachev, Valerii V.; Revinskii, Yurii V.; Tikhomirova, Karina S.; Starikov, Andrey G.; Dubonosov, Alexander D.; Bren, Vladimir A.; Aldoshin, Sergey M.; Minkin, Vladimir I.
• Is Part Of: Tetrahedron. Volume 72:Issue 38(2016)
• Page Start: 5776
• Page End: 5782
• Publication Date: 2016-09-22
• Subjects: Fulgide -- [1]Benzothiophene -- Furan-2, 5-dione -- X-ray diffraction -- Photochromism; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2016.08.002
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: Novel [1]benzothien-2-yl fulgides were synthesized and their structures established based on analysis by 1 H, 13 C NMR and IR spectroscopy, mass-spectrometry and X-ray diffraction. All the compounds exist in the ring-opened Z- isomeric forms. Under UV-irradiation fulgides with no substituent at the methylidene bridge undergo thermally or photochemically reversible Z/E -photoisomerization, but do not convert to the cyclic isomeric forms. Under the same conditions, 3-(1-(3-methyl[1]benzothien-2-yl)ethylidene)-4-(1-methylethylidene)-dihydrofuran-2, 5-dione with a methyl group at the methylidene bridge rearranges into the thermally stable colored 1, 3-cyclohexadiene ring-closed isomer which possesses improved spectral characteristics as compared with 2-thienyl and [1]benzothien-3-yl analogues. Irradiation with visible light results in the fast backward isomerization into the initial colorless hexatriene ring-opened form. Graphical abstract: Novel [1]benzothien-2-yl fulgides have been synthesized. Under irradiation the compounds with R 1 =H undergo reversible Z/E -photoisomerization, the compound with a methyl group ( R 1 =Me) at the methylidene bridge rearranges into the thermally stable colored ring-closed isomer.