Strange ‘Half-Mӧbius’ molecule has rare properties chemists have never seen before
Researchers have created an unusually twisted molecule with a never-before-seen electronic structure.
The new molecular architecture, called half-Mabius topology, “is another button we can flip to make and manipulate matter,” and expands our fundamental understanding of matter. physical And chemistryco-senior author Igor Rončevićlecturer in computational and theoretical chemistry at the University of Manchester in the United Kingdom, told Live Science.
A Möbius strip, created by twisting a ribbon 180 degrees and then joining the ends, is a mathematically interesting shape that results in a single continuous surface. This strange inverted geometry also has interesting implications for chemists, particularly when studying the electronic and spatial properties of molecular structures.
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Electrons in revolt
Usually, electrons are localized around a specific atom or bond, but a subset of cyclic compounds, called conjugated rings, allow electrons to travel freely throughout the loop, above and below the atoms. This delocalization makes the conjugated rings more stable than expected and also influences other properties, including color, optics, and reactivity.
However, in a Mabius molecule, the electron orbitals containing the electrons are twisted 180 degrees relative to each other at the junction where their ends meet. Electrons can still move across the entire molecule, but at this junction some of their properties cancel out, resulting in completely contrasting characteristics and behavior for the entire molecule.
“Chemistry thought these are the only two options,” Rončević said. “But our finding shows that there is another option, a third option, in which we can also rotate just 90 degrees.”
To achieve this, the team, co-led by Lion Grosssenior researcher at IBM Zurich, created two conjugated systems within a single ring of 13 carbon atoms. The ring contained two chlorine atoms bonded at positions 1 and 7 that insulated these conjugated systems and separated the electrons unevenly on either side. One side of the ring contained 13 electrons, while the other side contained only 11.
We have actually created a molecule with a completely new electronic structure and we want to see what else is possible.
Leo Gross, senior researcher at IBM Zurich
“The problem is that electrons like to associate,” Rončević said. “So to associate, they’re going to twist the molecule.”
The ring therefore spontaneously twists 90 degrees – pushing one chlorine atom up and the other down – to align these two separate conjugated systems. This then allows mixing between the two systems, allowing them to share their electrons throughout the molecule.
“At this point, we no longer have two separate systems; we have a single 24-electron system,” Rončević said. The resulting molecule therefore exhibits its own characteristic electronic and magnetic properties, distinct from standard and Möbius structures.
One last twist
The restricted twist angle of the half-Mabius molecule also gives rise to two possible versions of itself, called enantiomers.
Since the ring can twist left or right, the resulting molecules are mirror images of each other, much like left and right hands. This property, technically called chirality, is extremely important throughout chemistry, affecting everything from the synthesis of drug molecules to the production of OLEDs. Intriguingly, by applying a small external voltage, the team was able to freely interconvert a single molecule between the two enantiomers – something that is extremely difficult to achieve using conventional chemistry.
The team supported these experimental results with detailed calculations; the mind-blowing complexity of the half-Möbius electronic structure required a state of the art quantum computers. They published their findings on March 5 in the journal Science.
Looking ahead, the team intends to focus on exploring the fundamental theory and potential of these molecular architectures.
“We’ve actually created a molecule with a completely new electronic structure and we want to see what else is possible,” Gross said. “We could expand this and explore, for example, multiple half-Mabius or even braided twists.”
Rončević, I., Paschke, F., Gao, Y., Lieske, L., Gödde, LA, Barison, S., Piccinelli, S., Baiardi, A., Tavernelli, I., Repp, J., Albrecht, F., Anderson, HL and Gross, L. (2026). A molecule with a half-Möbius topology. Scienceeaea3321. https://doi.org/10.1126/science.aea3321
