N-Arylbenzonitrilium ions. Photochemical generation and effect of substituents in the phenyl rings on lifetimes in water and reactivity with azide ion
作者:Patrick H. Ruane、Abid R. Ahmed、Robert A. McClelland
DOI:10.1039/b107028m
日期:2002.1.23
Ph–CN+–iPr (2); thus the effect of replacing an N-alkyl group with N-phenyl is modest. These two cations are also shown to have similar lifetimes to iminium analogs, e.g. Ph–CHN+(Me)–Ph. Thus, addition of water to analogous sp and sp2 hybridized systems occurs at a similar rate, and the increased steric access to the nitrilium plays at most a modest role. For the series where substituents in Ar′ were varied
硝酸根离子Ar–C N + –Ar'已通过激光闪光光解 在含有20%的水溶液中 乙腈。这阳离子 是通过苯甲酰亚胺盐的光热解产生的 酯类Ar–CZ N–Ar'(Z = –OC 6 H 4 -4-CN),其中4-氰基苯氧化物为光化学离去基团。反应速率常数水测定(k w),叠氮化物离子(ka z)和氢氧化物(k OH)。这阳离子Ph–C N + –Ph居住的时间仅短50倍水相较于Ph–C N + –iPr(2);因此,用N-苯基取代N-烷基的作用不大。这两个阳离子还显示了与亚硝基类似物相似的寿命,例如Ph–CH N +(Me)–Ph。因此,除了水与sp和sp 2相似的杂合系统的发生率相似,并且增加进入腈的空间最多只起到适度的作用。对于Ar'中的取代基随Ar等于而变化的系列苯基,log k w的哈米特图与σ相关,其中ρ = −1.4。对于Ar变化的系列,数据与σ +的相关性更好,尽管ρ +仅为-0