Effects of Intramolecular Electric Fields in Molecules: EQR Coupling Constants

摘要

The variation in EQR coupling constants in chlorohyphen;, bromohyphen;, and iodobenzenes is interpreted in terms of intramolecular electric fields acting on the carbonmdash;halogen bonds. The proportionality factorscX's, relating such shifts to the effective electric fields are determined for the three types of bonds. ThecC1for a carbonmdash;chlorine bond agrees reasonably well with the value determined in experiments in external electric fields as long as the sign for the latter is chosen as positive. It is expected that further extensions of the method are possible.