The synthetic procedure of lithocholyl-N-(2-aminoethyl)amide yielded a mixture of several forms detected by solid state C-13 CP/MAS NMR although the solution state NMR unambiguously ascertained that the compound was pure. By recrystallization from various solvents one pure polymorph alongside with four solvates were isolated. The structures of the pure polymorph and the solvates were characterized by C-13 and N-15 CP/MAS NMR and powder X-ray diffraction (PXRD) methods. Variable contact time and dipolar dephasing experiments were employed to obtain optimized CP parameters and to distinguish various CH (n) (n = 0-3) resonances. CSA analyses of spinning side bands at different spinning rates showed small variations in the shielding tensor values of the carbonyl group between the pure polymorph (recrystallized from acetonitrile, tetrahydrofuran and 1,4-dioxane) and p-xylene solvate.
机构:
Washington Univ, Dept Chem, St Louis, MO 63130 USA
Washington Univ, Ctr Mat Innovat, St Louis, MO 63130 USARhein Westfal TH Aachen, D-52056 Aachen, Germany
机构:
Washington Univ, Dept Chem, St Louis, MO 63130 USA
Washington Univ, Ctr Mat Innovat, St Louis, MO 63130 USARhein Westfal TH Aachen, D-52056 Aachen, Germany