Projectile hydrogen molecules are central to a new green method for precisely breaking one of the most abundant and industrially important bonds you can find.
C–H bonds are very stable and as such their cleavage normally requires either a temperature above 300°C or treatment with something like irradiation – both of which can cause organic molecules to lose their functionality. Now a method developed by Leo Lau of Western University in Canada and colleagues can break C–H bonds without damaging the rest of the molecule.
Lau explains that although H2 is unreactive at room temperature, by raising its kinetic energy to more than 10eV it is possible to drive C–H cleavage when the H2 hits the H atom of a C–H bond. The H2 works as a light-mass projectile and differentiates its colliding partners by their atomic mass and ‘like the scalpel of a skilful surgeon’ only excises a hydrogen atom. The dissociation occurs nearly 100% of the time and all of the other bonds remain intact.
Read the original journal article in Green Chemistry:
Cleaving C–H bonds with hyperthermal H2: facile chemistry to cross-link organic molecules under low chemical- and energy-loads
Tomas Trebicky, Patrick Crewdson, Maxim Paliy, Igor Bello, Heng-Yong Nie, Zhi Zheng, Xiaoli Fan, Jun Yang, Elizabeth R. Gillies, Changyu Tang, Hao Liu, K. W. Wong and W. M. Lau
Green Chem., 2014, Advance Article, DOI: 10.1039/C3GC41460D