53119-60-1Relevant articles and documents
1,3-bicyclo[1.1.1]pentanediyl: The shortest rigid linear connector of phenylated photochromic units and a 1,5-dimethoxy-9,10-di(phenylethynyl) anthracene fluorophore
De Meijere, Armin,Ligang, Zhao,Belov, Vladimir N.,Bossi, Mariano,Noltemeyer, Matthias,Hell, Stefan W.
, p. 2503 - 2516 (2008/04/01)
An excess of bis-1,3-(4-iodophenyl)bicyclo[1.1.1]pentane, prepared in 63% yield by iodination of 1.3-diphenylbicyclo[1.1.1]pentane, was selectively mono-coupled with 9-ethynyl-1,5-dimethoxy-10-phenylethynylanthracene (26), and subsequently with the zinc derivatives of 1-(2-methyl/methoxy-4-methyl-5- phenylthiophen-3-yl)-2-(2-methyl/methoxy-4-methylthiophen-3-yl) perfluorocyclopentenes (38-H-41-H). Regioselective synthesis of the 2-unsubslituted thiophenes 38-H-41-H required intermediate prepara tion of 2-trimethylsilyl-3,5-dimethyl-4-bromothiophene (37) or 2-trimethylsilyl-5- methoxy-3-methyl-4-bromothiophene (40). Protection of the α-position of the thiophene ring with a 2-trimethylsilyl group blocks the rearrangement of the 4-lithio derivatives into the corresponding 2-lithiated thiophenes. With the bicyclo[1.1.1]pentane frag ment linking the photochromic units 1-3 and 1,5-dimethoxy-9,10-di(phenylethynyl)anthracene as a fluorescent part, quantitative resonance energy transfer between the excited state of the fluorophore (donor) and the closed form of the photochromic units 1-3 (acceptors) was observed. The closed forms of the methoxy-substituted photochromic units 2 and 3 are less resistant to UV light (313 nm) than the closed form of 1.
