Schnapp K A, Poe R, Leyva E, Soundararajan N, Platz M S
Department of Chemistry, Ohio State University, Columbus 43210.
Bioconjug Chem. 1993 Mar-Apr;4(2):172-7. doi: 10.1021/bc00020a010.
A series of fluorinated aryl azides and fluorinated azidobenzoates were studied by laser flash photolysis techniques. Using the pyridine ylide probe method it was possible to determine whether a singlet nitrene or ring-expanded ketenimine ylide is the trappable intermediate that is generated at ambient temperature. It was determined that two fluorine substituents, ortho and ortho' substituted relative to the azide group, are required to retard ring expansion and allow bimolecular capture of the singlet nitrene. LFP of ortho, ortho' difluorinated aryl azides in methanol produces the ground triplet state of the nitrene. The results are consistent with chemical analysis of reaction mixtures. The implications of this data for the design of photoaffinity labeling reagents are discussed.
通过激光闪光光解技术研究了一系列氟化芳基叠氮化物和氟化叠氮苯甲酸酯。使用吡啶叶立德探针法能够确定在室温下产生的可捕获中间体是单线态氮烯还是扩环烯酮亚胺叶立德。已确定相对于叠氮基团在邻位和邻'位取代的两个氟取代基是减缓环扩张并允许单线态氮烯进行双分子捕获所必需的。在甲醇中对邻、邻'二氟化芳基叠氮化物进行激光闪光光解产生氮烯的基态三重态。结果与反应混合物的化学分析一致。讨论了这些数据对光亲和标记试剂设计的意义。
