Optical stability of axially chiral push-pull-substituted buta-1,3dienes: Effect of a single methyl group on the C60 surface

A new spin on C60: Axially chiral, pushpull buta-1,3-diene chromophores conjugated to vicinally methylated fullerenes (see picture) have high barriers of rotation about their chiral axes. These high barriers allowed their optical resolution and the determination of the absolute configuration by comparison of experimental and calculated circular dichroism spectra. The methyl group is rigidly fixed upon the surface of the carbon sphere and is responsible for the high rotational barriers. (Figure Presented). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.