J. Am. Chem. Soc. 134, 142–145 (2012)

Polymerizing organic molecules to form synthetic nanotubes would allow researchers to take advantage of organic chemistry tools for nanotechnology applications. Joseph W. Lauher and his group have adopted an approach for producing tubular polymers in which macrocyclic monomers are designed to stack through π–π interactions, and which contain polymerizable units — two diacetylene groups in this case. The 34-atom monomer designed by the researchers forms a triclinic crystal with a favourable stacking distance to enable, on annealing, a single-crystal-to-single-crystal polymerization reaction covalently connecting the stacked monomers to form a synthetic nanotube. In principle, the monomer's cross-section is large enough to allow the inclusion of small molecules, however, the central opening of the nanotube becomes partially obstructed by a conformational tilt as the polymerization proceeds. Although the researchers demonstrate that it is possible with this approach to produce a fully chemically characterized tubular addition polymer (with a 1-nm-opening across the long axis and indefinite tube length), the challenge ahead is to make the nanotubes soluble and functional with ad hoc chemical modifications.