Dynamic nuclear magnetic resonance investigation of phosphonamidothioic and phosphonamidous chlorides
作者:James Burdon、Jacqueline C. Hotchkiss、W. Brian Jennings
DOI:10.1039/p29760001052
日期:——
chlorides, RP(S)(Cl)NPri2(R = Me, But, or Ph), show non-equivalent N-isopropyl groups in the proton n.m.r. spectra at low temperature. The barriers to isopropyl site-exchange have been determined by iterative bandshape analysis and lie in the range 9–12.6 kcal mol–1. These data are believed to refer to P–N bond rotation though alternative explanations are also considered. The corresponding NN-dimethyl
NN -二异丙基- P -alkylphosphonamidothioic氯化物,RP(S)(Cl)的NPR我2(R = Me中,卜吨,或pH),显示非等效Ñ在低温下在质子核磁共振谱-异丙基的基团。异丙基位点交换的障碍已通过迭代带状分析确定,范围为9–12.6 kcal mol –1。尽管也考虑了其他解释,但这些数据被认为是指PN键的旋转。相应的NN-二甲基化合物在低温下不显示任何N-甲基不等价性。R 1 P(Cl)–NR的某些类似膦酰亚磷化合物中PN键旋转的障碍还测量了2 2,并结合文献数据进行了讨论。尽管NN-二甲基化合物表现出与P-烷基取代基不同的反空间效应,但P–N旋转势垒通常随烷基取代基的空间体积而增加。该P -叔丁基的化合物不显示围绕在低温(-100至-150℃)的磷-碳键的旋转受阻的任何证据。