Abstract
Abiological NH3 synthesis under mild conditions on a PNP [=2,6-bis(di-tert-butyl-phosphinomethyl)pyridine] pincer chelating an Mo(N2)3 group has been reported and attributed to a catalytic cycle wherein only the equatorial N2 is reduced. The present calculations suggest that reduction of axial N2 ligands was the reason the cycle ended after production of 23 equiv. of NH3. NH3 detachment from axial NNH3 initiates a terminal reaction pathway by leaving an axial nitrido N behind on the Mo. The transinfluence of the strong axial nitride bond causes the second axial N2 to detach from the Mo, with N-Mo-N2 remaining as a non-catalytic, pincer-chelated group.
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ACKNOWLEDGMENTS
I am grateful to colleagues R. A. Kemp, D. R. Wheeler, D. Ingersoll, and S. L. Rempe for helpful discussions, and to G. Henkelman for assistance in implementing the dimer method.
Notes
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gcic.