Dinitrogen Dissociation on an Isolated Surface Tantalum Atom
P. Avenier,1
M. Taoufik,1*
A. Lesage,2
X. Solans-Monfort,3
A. Baudouin,1
A. de Mallmann,1
L. Veyre,
J.-M. Basset,1*
O. Eisenstein,4
L. Emsley,2
E. A. Quadrelli1*
Both industrial and biochemical ammonia syntheses are thought
to rely on the cooperation of multiple metals in breaking the
strong triple bond of dinitrogen. Such multimetallic cooperation
for dinitrogen cleavage is also the general rule for dinitrogen
reductive cleavage with molecular systems and surfaces. We have
observed cleavage of dinitrogen at 250°C and atmospheric
pressure by dihydrogen on isolated silica surface–supported
tantalum(III) and tantalum(V) hydride centers [(
Si-O)
2Ta
III-H]
and [(
Si-O)
2Ta
VH
3], leading to the Ta
V amido imido product [(
SiO)
2Ta(=NH)(NH
2)]:
We assigned the product structure based on extensive characterization
by infrared and solid-state nuclear magnetic resonance spectroscopy,
isotopic labeling studies, and supporting data from x-ray absorption
and theoretical simulations. Reaction intermediates revealed
by in situ monitoring of the reaction with infrared spectroscopy
support a mechanism highly distinct from those previously observed
in enzymatic, organometallic, and heterogeneous N
2 activating
systems.
2 Université de Lyon, Laboratoire de Chimie, UMR-5182 CNRS-ENS, Lyon, Ecole Normale Supérieure de Lyon, F-69364 Lyon Cedex, France.
3 Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
4 Institut Charles Gerhardt, UMR 5253 CNRS, UM 2- ENSCM, UM1, Chimie Théorique, Méthodologies, Modélisations, Université Montpellier 2, F-34095 Montpellier Cedex 05, France.
* To whom correspondence should be addressed. E-mail: quadrelli{at}cpe.fr (E.A.Q.); taoufik{at}cpe.fr (M.T.); basset{at}cpe.fr (J.-M.B.)
