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通过反 4 ( 4 R 苯乙烯基 )吡啶 [R =H(Ⅰa) ,Me(Ⅰb) ,OMe(Ⅰc) ,OH(Ⅰd) ,Me2 N(Ⅰe) ]在稀盐酸中的光二聚反应合成了 4个r 1 ,c 2 ,t 3,t 4 1 ,3 双 ( 4 R 苯基 ) 2 ,4 二 ( 4 吡啶基 )环丁烷 [R =H(Ⅱa) ,Me(Ⅱb) ,OMe(Ⅱc) ,OH(Ⅱd) ],除Ⅱa外 ,其余为新化合物 .光二聚反应具有高度立体选择性且几乎是定量完成的 .研究发现 ,随着取代基供电子能力的提高 ,光二聚反应速率下降 .反应的高度立体选择性以及该反应不受空气中氧气影响的事实表明光二聚反应是按激发单重态历程进行的 .研究还发现Ⅰa～Ⅰd在有机溶剂中主要发生反 顺异构化反应 ,随着溶剂极性增加 ,反 顺异构化速度加快 ,表明其反 顺异构化反应亦经激发单重态历程 .本文检测到了Ⅰa在稀盐酸溶液中的激基缔合物荧光 .
The compounds of the present invention were synthesized by photodimerization of 4 (4R styryl) pyridine [R = H (Ia), Me (Ib), OMe (Ic), OH (Id), Me2N 4 r 1, c 2, t 3, t 4 1, 3 bis (4 R phenyl) 2,4 di (4 pyridyl) cyclobutane [R = H (IIa), Me (IIb), OMe ( Ⅱc), OH (Ⅱd)], except for Ⅱa, the other is a new compound.The photodimerization is highly stereoselective and almost quantitatively completed.It is found that with the improvement of electron donating ability, the photodimerization reaction rate Decreased.The high stereoselectivity of the reaction and the fact that the reaction is not affected by the oxygen in the air indicate that photodimerization is carried out according to the excited singlet state.The study also found that Ⅰa ~ Reaction, with the increase of solvent polarity, the reaction speed of isostere isomerization was accelerated, indicating that the reaction of isostere isomerization was also excited by singlet state.The fluorescence of exciplex of Ⅰa in dilute hydrochloric acid solution was detected in this paper.