He described coordinating a pair of NHCs to a boron atom to make a borylene, :BHR2, where R is an NHC. This molecule is the first example of a persistent acyclic boron carbene analog. It’s a neutral molecule that is electronically similar to amines and phosphines, he said. The molecule is unusual, Bertrand pointed out, because boron is in the +1 oxidation state rather than the usual +3, which means it behaves as a Lewis base instead of a Lewis acid. By subsequently oxidizing the borylene, Bertrand’s group created a rare boron radical (Science, DOI: 10.1126/science.1207573). Bertrand also spoke about work in progress to use carbenes to isolate a persistent nitrene, :NR. Nitrenes are reactive carbene analogs used in chemical reactions and generated in situ from azides and isocyanates.
by Stephen K. Ritter |
April 23, 2012