Highly Active Iron Catalyst for Ammonia Borane Dehydrocoupling at Room Temperature

The iron complex [FeH(CO) (PNP)] (PNP = N-(CH(2)CH(2)PiPr(2))(2)) is a highly active catalyst for ammonia borane dehydrocoupling at room temperature. Mainly linear polyaminoborane is obtained upon release of 1 equiv of H-2. Mechanistic studies suggest that both hydrogen release and B-N coupling are metal-catalyzed and proceed via free aminoborane. Catalyst deactivation results from reaction with free BH3 that is formed by aminoborane rearrangement. Importantly, borane trapping with a simple amine allows for the observation of a TON that is unprecedented for a well-defined base metal catalyst.