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-methylt hiophen-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-bromothiophene (40). Protection of the alpha-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.

中文翻译：

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1,3-双环[1.1.1]戊二基：苯基化的光致变色单元和1,5-二甲氧基-9,10-二（苯基乙炔基）蒽荧光团的最短的刚性线性连接器。

将过量的1,3-二苯基双环[1.1.1]戊烷碘化，以63％的收率制得的双1,3-（4-碘苯基）双环[1.1.1]戊烷与9-乙炔基-1,5-二甲氧基-10-苯基乙炔基蒽（26），随后带有1-（2-甲基/甲氧基-4-甲基-5-苯基噻吩-3-基）-2-（2-甲基）的锌衍生物/甲氧基-4-甲基噻吩-3-基）全氟环戊烯（38-H-41-H）。区域选择性合成2-未取代的噻吩38-H-41-H需要中间体制备2-三甲基甲硅烷基-3,5-二甲基-4-溴噻吩（37）或2-三甲基甲硅烷基-5-甲氧基-3-甲基-4-溴噻吩（40）。用2-三甲基甲硅烷基保护噻吩环的α-位可阻止4-硫代衍生物重排成相应的2-锂化的噻吩。与双环[1.1。1]戊烷片段连接光致变色单元1-3和1,5-二甲氧基-9,10-二（苯基乙炔基）蒽作为荧光部分，荧光团（供体）的激发态与封闭形式之间的定量共振能量转移观察到了光致变色单元1-3（受体）的数目。甲氧基取代的光致变色单元2和3的封闭形式比1的封闭形式对紫外线（313 nm）的抵抗力更弱。