Strain can unlock electron-donating orbital in tetravalent carbon atoms

Strain amplifies tetravalent carbon atoms’ ability to donate electrons, facilitating various non-covalent interactions, quantum chemical calculations show. ‘Usually when a carbon atom is in a tetrahedral bonding situation, which is the most common, there’s no possibility for an electrophile to approach and interact with it. But if you bend back the four bonds that it’s attached to, you can get this to interact, and that has rarely been seen before,’ explains Steve Scheiner at Utah State University in the US, who co-led the study with Wiktor Zierkiewicz from Wrocław University of Science and Technology in Poland.