1H NMR utilization of through-space effects in configurational assignments. I—application to nitriles; determination of the separate effects of the electric field and anisotropy of the CN group
作者:Michel Rouillard、Serge Geribaldi、Jean Khazarian、Marcel Azzaro
DOI:10.1002/mrc.1270130504
日期:1980.5
AbstractThe changes in chemical shift induced by isomerization for all the ring protons of the Z‐ and E‐5,5‐dimethyl‐2‐cyclohexenylidene acetonitriles depend only on the through‐space effects of the cyano group. The configurational assignments were made taking into consideration the anisotropic and electric field effects, either separately or together. In the first case, the total effects are ΔXCNT=−14.7×10−6cm3 mol−1 and bμCNT=14.7×10−30 cm3, respectively. The second approach allows the estimation of the values ΔXCN=−4.9 × 10−6 cm3 mol−1 and bμCN=9.8 × 10−3 cm3, reflecting the combined contributions of magnetic anisotropy and electric field to the total effect.