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

Article abstract of DOI:10.1002/mrc.1270130504

The 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 Δ_χCN^T=-14.7E-6 cm³ mol^-1 and bμ_CN^T=14.7E-30 cm³, respectively.The second approach allows the estimation of the values Δ_χCN=-4.9E-6 cm³ mol^-1 and bμ_CN=9.8E-3 cm³, reflecting the combined contributions of magnetic anisotropy and electric field to the total effect.