New spiropyrans based on 1, 3-benzoxazine-2-one: acid catalyzed synthesis and theoretical insight into the photochromic activity. Issue 22 (1st June 2016)

• Record Type: Journal Article
• Authors: Ozhogin, Ilya V.; Dorogan, Igor V.; Lukyanov, Boris S.; Mukhanov, Eugene L.; Tkachev, Valery V.; Chernyshev, Anatoly V.; Lukyanova, Maria B.; Aldoshin, Sergey M.; Minkin, Vladimir I.
• Is Part Of: Tetrahedron letters. Volume 57:Issue 22(2016)
• Page Start: 2382
• Page End: 2385
• Publication Date: 2016-06-01
• Subjects: Spiropyran -- 1, 3-Benzoxazine -- Photochromism -- Acid catalyzed synthesis -- DFT calculations; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2016.04.054
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: [MeC(OH)2 ] + ClO4 − is a good catalyst for the synthesis of 1, 3-benzoxazine spiropyrans. Rotation of the nitro-group is involved in the main relaxation channel on the S1 PES. Excited-state structural relaxation determines photochromism of spiropyrans. Abstract: A new series of spiropyrans based on 1, 3-benzoxazine-2-one were synthesized using acid catalysis. Contrary to expectations, 6′-bromo-6-chloro-3-methyl-8′-nitro-spiro[1, 3-benzoxazine-4, 2′-chromene]-2-one and 6, 6′-dichloro-3-methyl-8′-nitro-spiro[1, 3-benzoxazine-4, 2′-chromene]-2-one did not exhibit photochromic behavior, which was explained by TD DFT calculations to be a consequence of the existence of an effective non-radiative decay pathway allowing the structural relaxation of the spiropyrans in the first singlet excited state.