Science http://doi.org/mq6 (2013)

Watching chemistry happen at the atomic level is a chemist's dream — and one that is now coming true. Using non-contact atomic force microscopy, Dimas de Oteyza and colleagues have obtained spectacular images of individual hydrocarbon molecules — with single-bond resolution — before and after a chemical reaction.

To study rearrangement reactions known as cyclization processes, de Oteyza et al. synthesized multicyclic hydrocarbon molecules on a silver surface and probed them using a single CO molecule tip. The high-resolution images reveal the mechanisms of thermally induced breaking and formation of molecular bonds, resulting in a variety of unexpected products. These observations, together with ab initio calculations, provide a clearer picture of the complex surface chemistry.

Cyclization processes are the key to the bottom-up molecular assembly of polyaromatic hydrocarbons and eventually of more complex graphene-like nanostructures.