* Astronomy

Molecule with a Split Personality as Porphyrinoid Switches Between Huckel and Mobius Topologies
If you take a strip of paper, twist one end by 180° and then stick the two ends together to form a ring, the result is called a Möbius strip, a geometric shape with only one surface and one edge. You can prove this by making a line along the strip with a pencil: Without lifting the pencil you get back to your starting point in the endwith the whole strip marked: at each point, both sides of the strip are marked by the line. Ring-shaped aromatic molecules can also have a topology like that of the Möbius strip, with only one side. Polish researchers have now made a porphyrin-like ring that can do something its paper analogue cant. As the team led by Lechoslaw Latos-Grazynski reports in the journal Angewandte Chemie, the new molecule can switch back and forth between the one-sided Möbius topology and a normal two-sided state (Hückel topology)without breaking the ring.

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