The recent report[1] of what is termed a “half-Möbius” molecule is generating a lot of excitement. It was generated as part of a project to make odd-numbered cyclocarbons on STM (scanning tunnelling microscope) surfaces. I had discussed even-numbered cyclocarbons in another post[2], where I also happened to include several odd-numbered examples, such as C49 and C51. In this study[1] they were focussing on C13 and a precursor to this was to be C13Cl2. As part of the microscopy, they noticed this latter species was asymmetric (chiral) and so started the story of a “half-Möbius” molecule (molecules with twists in their topology are of course chiral). I should at this stage say that the concept of a half-Möbius is quite new and thought provoking. Perhaps the simplest way of explaining why, is that a conventional Möbius molecule (as with the strip or ribbon) requires two full circuits of the edge of the ribbon to return to the start, whereas this half version requires a full four circuits to achieve the same. More about this later. (more…)
References
- I. Rončević, F. Paschke, Y. Gao, L. Lieske, L.A. Gödde, S. Barison, S. Piccinelli, A. Baiardi, I. Tavernelli, J. Repp, F. Albrecht, H.L. Anderson, and L. Gross, "A molecule with half-Möbius topology", Science, 2026. https://doi.org/10.1126/science.aea3321
- H. Rzepa, "Molecules of the year 2025: Cyclo[48]carbon and others – the onset of bond alternation and the Raman Activity Spectrum.", 2025. https://doi.org/10.59350/g4309-gv109