Self-Assemblies, Folding, and Properties of Perylene Monomers, Oligomers, and Polymers - Molecular Self-Assembly: Advances and Applications - page 178

Figure 5.20 NMR monitors isomerization reaction. Top: exhibits one

peak for all eight identical aromatic protons (left, red) and
only one triplet for protons adjacent to the disulfide bonds
(right, blue). Bottom:

2B

reaching a
50/50 diastereomeric mixture in about 24 h. The mixture
then exhibits two equally integrated perylene peaks and two
equal triplets for protons adjacent to the disulfide. Solvent:
CDCl

2B interconverts to 2K

.

3

To determine if the two compounds were truly interconverted
diastereomers, normal-phase HPLC was used to separate and purify
the suspected isomers. The compounds separated surprisingly well,
with heterochiral cyclic dimer 2K eluting before the homochiral cyclic

because of the more steric and soluble heterostructure
(Fig. 5.21). The separate fractions were collected, and immediately
characterized by mass spectrometry (ESI); each compound exhibited
identical mass and isotopic distributions consistent with the cyclic
dimer containing eight chlorine atoms (Fig. 5.21).

dimer 2B