Stereochemistry in Solution. IV. Conformational Preference of the Non-bonded Electron Pair of Nitrogen in Piperidine Derivatives. Effective Size of the Lone Paired Electrons

From the IR spectrum in C-D stretching region of 2, 6-dideuterated piperidine, N-methylpiperidine, and N-isopropylpiperidine, quantitative evaluation was made about conformational preference of the non-bonded electron pair of nitrogen, Thirty percent of the lone pair was proved to exist in equatorial position in piperidine molecule in carbon tetrachloride.