CONFORMATIONAL DYNAMICS OF TRIPLE ROTORS - TRIS(DIMETHYLAMINO)METHANE, TRIISOPROPYLAMINE, AND RELATED MOLECULES

NMR spectra and their temperature-dependence are reported for tris(dim ethylamino)methane (1), for tris(diethylamino)methane (2), for triisop ropylamine (3), and for N,N-diisopropyl-3-pentylamine (4) and are disc ussed in terms of the conformations adopted and interconversion of the se conformations, as indicated by molecular mechanics calculations. So lid state NMR spectra, obtained by freezing the neat liquids at low te mperatures, were also used to support the conclusions of the conformat ional analysis. Proton NMR spectra of protonated forms of 3 and 4 were similarly analyzed. Less crowded triple rotors prefer a gauche, gauch e, gauche conformation while more crowded ones adopt an anti, gauche, gauche arrangement.