(Figure Presented) The greenhouse gas N 2O is converted to N 2 by a μ-sulfido-tetracopper active site in the enzyme nitrous oxide reductase (N 2OR) via a process postulated to involve μ-1,3 coordination of N 2O to two Cu(I) ions. In efforts to develop synthetic models of the site with which to test mechanistic hypotheses, we have prepared a localized mixed valent Cu(II)Cu(I) 2 cluster bridged in a μ-η 2:η 1:η 1 fashion by disulfide, [L 3Cu 3(μ 3-S 2)]X 2 (L = 1,4,7-trimethyltriazacyclononane, X = O 3SCF 3 - or SbF 6 -). This cluster exhibits spectroscopic features superficially similar to those of the active site in N 2OR and reacts with N 2O to yield N 2 in a reaction that models the function of the enzyme. Computations implicate a transition state structure that features μ-1,1-bridging of N 2O via its O-atom to a [L 2Cu 2(μ-S 2)] + fragment and provide chemical precedence for an alternative pathway for N 2O reduction by N 2OR.
|Original language||English (US)|
|Number of pages||3|
|Journal||Journal of the American Chemical Society|
|State||Published - Mar 4 2009|