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
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
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DOI：
10.1002/chem.200601316
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发表时间：
2007-01-01
影响因子：
4.3
通讯作者：
Hell, Stefan W.
中科院分区：
文献类型：
--
作者：
de Meijere, Armin;Zhao, Ligang;Hell, Stefan W.
过量的双-1,3-（4-碘苯）双环[1.1.1]戊烷通过1,3-二苯基双环[1.1.1]戊烷碘化，以63%的产率与9-乙基-1,5-二甲氧基-10-苯乙基- thracene（26）选择性单偶联，随后与1-（2-甲基/甲氧基-4-甲基-5-苯基噻吩-3-基）- 2-（2-甲基/甲氧基-4-甲基噻吩-3-基）全氟环戊烯（38-H-41-H）的锌衍生物选择性单偶联。2-未取代噻吩38-H-41-H的区域选择性合成需要中间制备2-三甲基硅基-3,5-二甲基-4-溴噻吩（37）或2-三甲基硅基-5-甲氧基-3-甲基-4-溴噻吩（40）。用2-三甲基硅基保护噻吩环的a位，阻止了4-锂衍生物重排成相应的2-锂化噻吩。以连接光致变色单元1-3和1,5-二甲氧基-9,10-二（苯乙基）蒽的双环[1.1.1]戊烷片段作为荧光部分，观察了荧光团（供体）激发态和光致变色单元1-3（受体）闭合态之间的定量共振能量转移。甲氧基取代的光致变色单元2和3的封闭形式对紫外光（313 nm）的抗性低于封闭形式1。
An excess of bis-1,3-(4-iodophenvl)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-phenylethynylan- thracene (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-unsubstituted thiophenes 38-H-41-H required intermediate preparation of 2-trimethylsilyl-3,5-dimethyl-4-bromothiophene (37) or 2-trimethylsilyl-5-methoxy-3-methyl-4-bromothio- phene (40). Protection of the a-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 fragment 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.