N activation on a molybdenum-titanium-sulfur cluster.

The FeMo-cofactor of nitrogenase, a metal-sulfur cluster that contains eight transition metals, promotes the conversion of dinitrogen into ammonia when stored in the protein. Although various metal-sulfur clusters have been synthesized over the past decades, their use in the activation of N has remained challenging, and even the FeMo-cofactor extracted from nitrogenase is not able to reduce N. Herein, we report the activation of N by a metal-sulfur cluster that contains molybdenum and titanium. An N moiety bridging two [MoSTi] cubes is converted into NH and NH upon treatment with Brønsted acids in the presence of a reducing agent.