Activation of Dinitrogen by Osmium Salen Complexes

This main purpose of the proposed investigation is to study the activation of dinitrogen by osmium salen complexes. Although the Haber-Bosch process easily produces ammonia from N2 and H2, a high temperature and pressure is required. On the other hand, nature makes use of a class of enzymes called nitrogenases to convert nitrogen to ammonia under mild conditions. Although a number of metal systems are able to cleave the N≡N bond, activation of N2 by osmium complexes has yet to be achieved. In a previous project, the investigators have synthesized a series of osmium nitrido complexes containing salen ligands. In this project, these nitrido complexes will be used to prepare a series of osmium dinitrogen complexes. Various strategies will then be used to cleave the N≡N bond in these complexes. This research should contribute to the development of more efficient chemical methods for the activation of dinitrogen, and to the understanding of the mechanism of biological nitrogen fixation.