Dipole moments of some N-phenyl-substituted derivatives of pyrrolidine, piperidine, morpholine, and thiomorpholine

Abstract

Apparent dipole moments in benzene of various p-substituted N-phenyl derivatives of pyrrolidine, piperidine, morpholine, and thiomorpholine and of some analogous NN-diethylanilines have been determined.

Vector moments along the bisector of angle CH₂[graphic omitted]CH₂ and also in the direction of the major axis of the aromatic ring have been calculated for the parent compounds. The order of magnitude of the latter is N-phenylpyrrolidine > NN-diethylaniline > N-phenylpiperidine > N-phenylmorpholine > N-phenyl-thiomorpholine. The nature of the heterocycle does not greatly affect the additional moments, µ(add.), along the major axis of the aromatic ring, required to account for the moments of the p-substituted compounds. In each series of compounds, µ(add) parallels the Hammett substituent constant, σ.