ANALYSIS OF THIOCYANATES BY NMR

Abstract

An unexpected nmr spectrum of β-phenyl ethyl thiocyanate in CDCl₃ solution has led to its analysis in a series of solvents of increasing polarity. Changes in polarity produce increments of ^δAB, transforming the signal from a singlet for 4 methylenic protons to a clear A₂B₂ pattern. Signals appear to split following increasing values of dielectric constants and dipole moments. Rotational isomerism is assumed to be the reason for it since the reaction field parameter depends directly on the dipole moments of rotamers, thus changes in their population affect the reaction field and ultimately the chemical shifts.