Molecular self-assembly inhibition leads to basket-shaped cyclophane formation with chiral dynamics.
Planar perylene derivatives form macrocyclic dimers and concatenated dimer-dimer rings under the action of molecular self-assembly. If this underpinning principle is true, highly twisted perylene derivatives should be more frustrated toward formation of multimeric cyclic compounds such as macrocyclic dimers and concatenated dimer-dimers because of perturbation resulting from intermolecular pi-pi stacking. Indeed, 1,6,7,12- tetraphenoxy-substituted perylene is highly twisted and undergoes unimolecular cyclization rather than bimolecular or multimolecular cyclization. The resulting monocyclic monomer exhibits interesting conformation switching from one chiral structure (left-handedness) to another chiral structure (right-handedness) at room temperature. NMR studies of conformational dynamics reveal that such configuration change between the two enantiomers can be frozen at low temperature (-45 degrees C). An activation enthalpy barrier of 13.4 +/- 0.5 kcal.mol-1 for twisting the perylene plane in order to convert from one enantiomer to the other has been found.
Wang
Wei
W
Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.
Bain
Alex D
AD
Wang
Li-Qiong
LQ
Exarhos
Gregory J
GJ
Li
Alexander D Q
AD
D003500:Cyclization; D019281:Dimerization; D004988:Ethers, Cyclic / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010569:Perylene / Q000737:chemistry; D012399:Rotation; D013237:Stereoisomerism
D004988:Ethers, Cyclic; D010569:Perylene