Chemistry Department Colloquium

Dinitrogen (N2), 78 % of the earth's atmosphere, holds a unique position amongst small molecules, in that there is only one industrial process that uses it as a feedstock. The Haber Bosch process, which is a highly optimized, heterogeneous iron-catalyzed system based on iron, is used to make ammonia that is used for fertilizer to feed half of the world's human population, and which could be a future energy carrier to replace fossil fuels. Small scale conversions that operate under ambient conditions could offer food and energy justice to remote populations. Chemists have spent more than a century trying to make catalysts that can convert N2 under mild conditions, and a few catalysts for N2 conversion to ammonia or tris(silyl)amine have been developed, based on electron rich metals inspired by nature such as molybdenum. We have developed a new system, using electron deficient, and earth abundant metals formed into a metallacyclic cage with aromatic ligands, that traps dinitrogen, and funnels electrons and electrophiles to the N atoms, both demonstrating the first nitrogen reduction catalysis by a range of electropositive metal complexes, and enabling the first selective formation of bis(functionalized)amines by any catalyst.