'Molecular armour' from Japan: a cage that holds flat molecules by shape alone — even at 200°C

Some cages hold things by charge or chemistry. This one holds them by fit. At Japan's Institute for Molecular Science, researchers Haruka Kano, Takashi Harimoto and Yasutomo Segawa built a tiny cage from two curved panels that sandwiches flat, ring-shaped molecules — the building blocks of many medicines and materials. Small guests slip in and out through side openings, with one shape held about 90 times more strongly than a near-identical one, while larger guests built into the cage during assembly stayed trapped even at 200°C under vacuum, whatever their electronic properties. Published in the Journal of the American Chemical Society, the work hints at new ways to sort, protect and deliver molecules by shape alone.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation