Metallacyclic actinide catalysts for dinitrogen conversion to ammonia and secondary amines

Chemists have spent over a hundred years trying to make ambient temperature/pressure catalytic systems that can convert atmospheric dinitrogen into ammonia or directly into amines. A handful of successful d -block metal catalysts have been developed in recent years, but even binding of dinitrogen to an f -block metal cation is extremely rare. Here we report f -block complexes that can catalyse the reduction and functionalization of molecular dinitrogen, including the catalytic conversion of molecular dinitrogen to a secondary silylamine. Simple bridging ligands assemble two actinide metal cations into narrow dinuclear metallacycles that can trap the diatom while electrons from an externally bound group 1 metal, and protons or silanes, are added, enabling dinitrogen to be functionalized with modest but catalytic yields of six equivalents of secondary silylamine per molecule at ambient temperature and pressure. Metallacycles formed from two large, under-coordinated actinide M IV cations and two rigid arene-bridged aryloxide ligands are capable of binding dinitrogen inside their cavity. These f -block complexes can catalyse the reduction and functionalization of dinitrogen as well as the catalytic conversion of molecular dinitrogen to a secondary silylamine.