Topological explorations with a clip:  new molecular nanocarbons
The lack of synthetic control over the chirality of curved carbon nanostructures derived from graphene, such as carbon nanotubes (CNTs), prevents the development of molecular electronics applications that require high purity and uniformity of these materials. Single- and multi-walled CNTs are typically formed as a mixture of chiral, armchair, and zigzag nanostructures that significantly differ in their properties. The urgency of controlled chirality-specific synthesis of CNTs advanced the synthesis of curved molecular nanocarbons – molecular precursors for a stepwise synthesis of uniform single-walled CNTs. Applications in bioimaging, sensing, catalysis, and organic electronics have been rapidly emerging on account of the unusual properties of these hoop-like molecular nanocarbons.

To this date, no analogous molecular precursors for topologically more complex carbon nanostructures such as double-walled CNTs or carbon nanoscrolls exist because their topologies do not yet have a stable molecular representation.

TOPOCLIP develops such stable molecular representations, enables their synthesis by using a molecular clip, and delivers unprecedented topological molecular nanocarbons. The molecular clip helps controlling the curvature, preserves the electronic communication throughout the molecular nanocarbon structure, or allows construction of the first molecular nanocarbon with a reversible dynamic behavior. TOPOCLIP (1) improves our understanding of strain and non-covalent interactions that (de)stabilize curved nanocarbons, (2) delivers responsive nanocarbons that can alter shape with an external stimulus, and (3) establishes design principles for tailor-made molecular nanocarbons for future nano- and biotechnology applications. Ultimately, TOPOCLIP takes the vital step to find a solution to a long-standing challenge: the chirality-specific synthesis of carbon nanostructures of complex topologies obtained by rolling-up a graphene sheet beyond the single-walled CNTs.