N. Pavliček et. al., Nature Nanotechnology 12, 3 (13 February 2017) © MacMillan Publisher Ltd.

Scientists synthesize long-sought triangle-shaped molecule

Researchers have synthesized a triangle-shaped molecule they’ve had in their sights for nearly 7 decades. When atoms come together to form molecules, electrons on different atoms pair up to form bonds that lock the molecule together. Molecules called free radicals have a leftover unpaired electron, an arrangement that makes them highly reactive, eager to pair that remaining electron. But in rare cases molecules with an even number of electrons can behave like radicals, because the arrangement of their atoms prevents all the electrons from finding partners with which to pair up. In 1950, Czech chemist Erich Clar predicted that a triangle-shaped hydrocarbon made from six fused circular benzene molecules would have an even number of atoms and electrons but be unable to pair two of its electrons due to the molecule’s geometry. Clar tried to synthesize this molecule—called triangulene—in solution, but failed because it was so reactive it immediately bound up with other triangulene fragments. Now, researchers have succeeded by first synthesizing a larger precursor that has a couple of extra hydrogen atoms on it that stabilize the molecule. They then blasted their molecule with an electron beam to tear off the extra hydrogens, leaving them with triangulene, and an impressive molecular portrait (pictured). Triangulene’s unique electronic arrangement is expected to make it magnetic and could make it valuable for quantum computing.