Cleavage of the almost inert N 2 molecule, with its extremely strong N_N bond, represents a major chemical challenge. To date, only a single N2 cleavage reaction has been discovered for which a discrete, low-temperature stable, N 2-bound intermediate has been isolated in solution. This reaction of Laplaza and Cummins converts a three-coordinate Mo(III) complex via this intermediate to a Mo_N species. A knowledge of the structure of the intermediate is vital in approaching a quantitative understanding of the chemistry of N 2 cleavage. We have used molybdenum K-edge XAS, and have applied state-of-the-art multiple scattering analysis techniques to show that the intermediate is a linear Mo_N=N_Mo moeity with a Mo____Mo distance of 4.94 w and a _N=N_ bond-length of 1.19 w. The analysis was performed using the ab initio code FEFF in conjunction with the curve-fitting programs of EXAFSPAK, and included 19 distinct scattering paths, with significant contributions from multiple scattering paths of up to six legs in extent. Structural information on this solution species, stable only at low temperatures, could not have been obtained using any other technique.
Showing the most recent 10 out of 604 publications