All-Carbon Scaffolds by Rational Design

• Published in: Advanced materials (Weinheim) 2010-02, Vol.22 (7), p.803-812
• Main Authors: Diederich, François, Kivala, Milan
• Format: Article
• Language: English
• Subjects: Acetylene - chemistry; Acetylenic macrocycles; Bridged Bicyclo Compounds - chemistry; Carbon - chemistry; Chiroptic materials; Chromophores; Circular Dichroism; Fullerenes; Macrocyclic Compounds - chemistry; Optoelectronic materials; Scaffolding
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.200902623

The search for new molecular and regular polymeric allotropes of carbon has greatly stimulated the preparation and investigation of π‐conjugated acetylenic macrocycles, which often represent substructures of proposed 2D carbon networks. Perethynylated dehydroannulenes, expanded radialenes, and radiaannulenes with large, multi‐nanometer‐sized all‐carbon cores are potent electron acceptors, and their optoelectronic as well as stability and solubility properties are greatly enhanced by peripheral donor substitution. Acetylenic scaffolding into three dimensions has generated an expanded cubane with a C56 core, the first representative of a new class of “platonic” objects. Exceptional chiroptical properties displayed by enantiomerically pure alleno‐acetylenic, shape‐persistent macrocycles promise fascinating perspectives for the development of molecular and supramolecular chiroptical materials. Acetylenic scaffolding provides access to a diversity of planar, macrocyclic all‐carbon π‐chromophores, which include perethynylated dehydroannulenes, perethynylated expanded radialenes, and radiaannulenes and are potent electron acceptors. Peripheral substitution with electron donors leads to strongly enhanced optoelectronic properties and increased solubility and stability. Enantiomerically pure alleno‐acetylenic macrocycles represent new chiral carbon‐rich molecular architectures, featuring outstanding chiroptical responses.