Infrared C–D Stretching and 2H NMR Spectra of Isopropyl-2-d 1-(p-Substituted Phenyl)ethyl Ketones. Evidence for the Hydrogen Bond-Like Interaction between C–D Group and Aromatic π-Electrons

Abstract

Abstract Isopropyl-2-d 1-(p-X-phenyl)ethyl ketones (where, X=H, NO2, Br, Cl, C2H5, CH3, and NH2) were shown to have two absorption bands in the C–D stretching region. The absorption band at the higher frequency (ca. 2177 cm−1) is assigned to the C–D···π approached conformer, and the high frequency shift is ascribed to the effect of steric compression. Weak C–D···π hydrogen bond was shown to occur by the measurement of the substituent effect on the formation constant and the relative enthalpy of the C–D···π approached conformer.