2011 Science News of the Year: Molecules
By Science News
Molecular muscle does the job
Chemists often wish they could reach into a test tube and physically force a chemical reaction — and now they’ve come pretty darn close. In a feat of molecular arm-twisting, researchers attached polymer chains to an extremely stable ring-shaped molecule and tore it in two (SN Online: 9/15/11). The new approach split the triazole ring, a compound found in many drugs and fungus-fighting chemicals, into its molecular building blocks, reversing the reaction that brought the ring together.
“It’s a way to almost literally put your hands on molecules and twist them or turn them in whatever way you want,” says Christopher Bielawski of the University of Texas at Austin, who led the research. Chemists often use heat to break compounds apart, but the approach can yield a variety of molecular pieces. And heat and other chemical tricks don’t work on the triazole ring, because it is too tough.
Bielawski and his students attached chains to opposite sides of the rings in solution and then inserted an ultrasound probe. The probe generated imploding bubbles, creating tiny pockets of suction that yanked on the polymer chains and tore open the rings. The technique reverses a reaction that was thought to go in only one direction, suggesting a new means for strong-arming other molecules into interesting new chemistry.