Synthesis and Photochemical Properties of Stilbenophanes Tethered by Silyl Chains. Control of (2π + 2π) Photocycloaddition, Cis−Trans Photoisomerization, and Photocyclization

• Published in: Journal of organic chemistry Vol. 70; no. 24; pp. 9693 - 9701
• Main Authors: Maeda, Hajime, Nishimura, Ko-ichi, Mizuno, Kazuhiko, Yamaji, Minoru, Oshima, Juro, Tobita, Seiji
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 25-11-2005
• Subjects: Alicyclic compounds; Alicyclic compounds, terpenoids, prostaglandins, steroids; Chemistry; Exact sciences and technology; General and physical chemistry; Organic chemistry; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Preparations and properties; Intramolecular reaction; Photoisomerization; Triplet; Organic silane; Selectivity; Photochemical reaction; Quantum yield; Stilbene derivatives; Macrocycle; Stereoselectivity; Cycloaddition; Cyclization; Photoinduction; Fluorescence yield; Excimer; Benzenic compound; Cyclophane; Chemical synthesis; Sensitizer
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo050914+

Novel macrocyclic and medium-size stilbenophanes tethered by silyl chains were synthesized, and their photochemical and photophysical properties were examined. Direct photoirradiation of macrocyclic stilbenophanes gave intramolecular photocycloadducts stereoselectively, and the efficiency increased with decreasing distance between the two stilbene units. The triplet-sensitized photoreaction of stilbenophanes caused cis−trans photoisomerization. Photoreactions of cis-fixed stilbenophanes under an oxygen atmosphere selectively gave phenanthrenophanes. Fluorescence quantum yields increased with the introduction of silyl substituents, and hence those of silyl-tethered stilbenophanes were larger than that of unsubstituted trans -stilbene. Intramolecular excimer emission was observed when the distances between two stilbene units in the stilbenophanes were sufficiently small.