Cycloparaphenylenes (CPPs) are hoop-shaped π-conjugated molecules in which paraphenylene units are linked in a cyclic manner. They represent the simplest structural unit of armchair carbon nanotubes.
Shigeru Yamago, Kyoto University, Japan, and colleagues, recently reported the first example of a host–guest complex of CPP and C60. Such host–guest complexes are suitable models for elucidating convex–concave π–π interactions.
Now they treated a mixture of CPPs with C60. CPP selectively encapsulated C60 forming the shortest fullerene-peapod (see picture). Such complementary host–guest complexes could be useful for the size- and shapeselective separation of higher fullerenes and carbon nanotubes.
- Size-Selective Encapsulation of C60 by Cycloparaphenylene: Formation of the Shortest Fullerene-Peapod,
Takahiro Iwamoto, YoshikiWatanabe, Tatsuya Sadahiro, Takeharu Haino, Shigeru Yamago,
Angew. Chem. Int. Ed. 2011, 50.