利用紫精可以活化水中溶解氧的特性,设计合成了苯-紫精化合物(BEV).利用紫外吸收、电化学及核磁等方法研究了BEV与八元瓜环CB[8]之间的相互作用.实验结果表明,2种化合物可以进行主客体超分子自组装形成1∶1的二元包合物BEV-CB[8].同时,分别考察了化合物BEV和BEV-CB[8]与小牛胸腺DNA的相互作用,并采用琼脂糖凝胶电泳研究了氙灯光照下化合物对pBR322 DNA的切割能力.结果表明,CB[8]的引入改变了化合物BEV与DNA的作用方式,使嵌入作用和静电作用增强.光照结果说明只有超分子BEV-CB[8]在光照下可以完全切割质粒DNA,即CB[8]的存在明显提高了BEV对质粒DNA的切割效率.%Combining supramolecular chemistry with biochemistry was a new research direction. In this paper, self-assembly between a host compound CB [ 8 ] with a guest molecule benzyl viologen ( BEV) was examined by UV absorption measurement, cyclic voltammetric method and 'H NMR technique. The experimental results revealed that CB[8] included benzyl and part of pyridinum of BEV to form binary compounds BEV-CB[8], and when BEV2+ was reduced to BEV+' , a new stable ternary complex (BEV+' )2/CB[8] would be formed. The two kinds of viologens, BEV and BEV-CB[8] , were used for DNA photocleavage studies in physiological environment following the research results that CB [ 8 ] could enhance the interaction between BEV and CT DNA with intercalation and electrostatic interaction. Only 50 u,mol/L of the complex BEV-CB[8] could cleave SC pBR 322 DNA completely compared with BEV, which showed no ability for DNA clea-vage under the irradiation of Xe lamp. The main reason was that BEV2+ was reduced to BEV*' under irradiation and CB[8] bound BEV+' tightly to form (BEV+)2/CB[8] , which prolonged the lifetime of viologen radical BEV+' , causing the dissolved oxygen in water activation and the reactive oxygen species, -OH and O-2' , could cleave SC pBR 322 DNA. The results indicate an important application by host molecule CB[n] in supramolecular chemistry, which gives an obviously evidence for the field of DNA cleavage.
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