Internal motions in a fulleropyrrolidine tertiary amide with axial chirality.

The kinetic parameters for topomerization around the N-CO bond and enantiomerization around the C-CO bond in N-1-naphthoyl fulleropyrrolidine 1 and N-1-naphthoyl pyrrolidine 2 have been determined by dynamic NMR (line shape simulation and selective inversion transfer). The DeltaS(not =) values are negligible. The DeltaH# value for topomerization of 1 is smaller with respect to that of 2 by 4.3 kcal mol(-1) (explained by the electron-withdrawing effect of fullerene) and the value for enantiomerization is greater by 1.4 kcal mol(-1) (explained by the greater rigidity of the fulleropyrrolidine ring, as confirmed by ab initio analyses). Copyright 2004 American Chemical Society