TY - JOUR
T1 - Synthesis, Structure, and Reactivity of Uranium(VI) Nitrides
AU - Barluzzi, Luciano
AU - Hsueh, Fang-che
AU - Scopelliti, Rosario
AU - Atkinson, Benjamin E.
AU - Kaltsoyannis, Nikolas
AU - Mazzanti, Marinella
N1 - Funding Information:
We acknowledge support from the Swiss National Science Foundation grant number 200021_178793 and the Ecole Poly-technique Fédérale de Lausanne (EPFL). We thank R. Moinat and F. Sepulveda for carrying out the elemental and mass spectrometry analyses, F. Fadaei-Tirani for important contributions to the X-ray single crystal structure analyses. BEA and NK acknowledge the assistance given by Research IT, and the use of the Computational Shared Facility and the HPC Pool funded by the Research Lifecycle Programme at The University of Manchester.
Publisher Copyright:
© The Royal Society of Chemistry 2021.
PY - 2021/6/21
Y1 - 2021/6/21
N2 - Uranium nitride compounds are important molecular analogues of uranium nitride materials such as UN and UN
2which are effective catalysts in the Haber-Bosch synthesis of ammonia, but the synthesis of molecular nitrides remains a challenge and studies of the reactivity and of the nature of the bonding are poorly developed. Here we report the synthesis of the first nitride bridged uranium complexes containing U(vi) and provide a unique comparison of reactivity and bonding in U(vi)/U(vi), U(vi)/U(v) and U(v)/U(v) systems. Oxidation of the U(v)/U(v) bis-nitride [K
2{U(OSi(O
tBu)
3)
3(μ-N)}
2],1, with mild oxidants yields the U(v)/U(vi) complexes [K{U(OSi(O
tBu)
3)
3(μ-N)}
2],2and [K
2{U(OSi(O
tBu)
3)
3}
2(μ-N)
2(μ-I)],3while oxidation with a stronger oxidant (“magic blue”) yields the U(vi)/U(vi) complex [{U(OSi(O
tBu)
3)
3}
2(μ-N)
2(μ-thf)],4. The three complexes show very different stability and reactivity, with N
2release observed for complex4. Complex2undergoes hydrogenolysis to yield imido bridged [K
2{U(OSi(O
tBu)
3)
3(μ-NH)}
2],6and rare amido bridged U(iv)/U(iv) complexes [{U(OSi(O
tBu)
3)
3}
2(μ-NH
2)
2(μ-thf)],7while no hydrogenolysis could be observed for4. Both complexes2and4react with H
+to yield quantitatively NH
4Cl, but only complex2reacts with CO and H
2. Differences in reactivity can be related to significant differences in the U-N bonding. Computational studies show a delocalised bond across the U-N-U for1and2, but an asymmetric bonding scheme is found for the U(vi)/U(vi) complex4which shows a U-N σ orbital well localised to UN and π orbitals which partially delocalise to form the U-N single bond with the other uranium.
AB - Uranium nitride compounds are important molecular analogues of uranium nitride materials such as UN and UN
2which are effective catalysts in the Haber-Bosch synthesis of ammonia, but the synthesis of molecular nitrides remains a challenge and studies of the reactivity and of the nature of the bonding are poorly developed. Here we report the synthesis of the first nitride bridged uranium complexes containing U(vi) and provide a unique comparison of reactivity and bonding in U(vi)/U(vi), U(vi)/U(v) and U(v)/U(v) systems. Oxidation of the U(v)/U(v) bis-nitride [K
2{U(OSi(O
tBu)
3)
3(μ-N)}
2],1, with mild oxidants yields the U(v)/U(vi) complexes [K{U(OSi(O
tBu)
3)
3(μ-N)}
2],2and [K
2{U(OSi(O
tBu)
3)
3}
2(μ-N)
2(μ-I)],3while oxidation with a stronger oxidant (“magic blue”) yields the U(vi)/U(vi) complex [{U(OSi(O
tBu)
3)
3}
2(μ-N)
2(μ-thf)],4. The three complexes show very different stability and reactivity, with N
2release observed for complex4. Complex2undergoes hydrogenolysis to yield imido bridged [K
2{U(OSi(O
tBu)
3)
3(μ-NH)}
2],6and rare amido bridged U(iv)/U(iv) complexes [{U(OSi(O
tBu)
3)
3}
2(μ-NH
2)
2(μ-thf)],7while no hydrogenolysis could be observed for4. Both complexes2and4react with H
+to yield quantitatively NH
4Cl, but only complex2reacts with CO and H
2. Differences in reactivity can be related to significant differences in the U-N bonding. Computational studies show a delocalised bond across the U-N-U for1and2, but an asymmetric bonding scheme is found for the U(vi)/U(vi) complex4which shows a U-N σ orbital well localised to UN and π orbitals which partially delocalise to form the U-N single bond with the other uranium.
U2 - 10.1039/D1SC01796A
DO - 10.1039/D1SC01796A
M3 - Article
C2 - 34194699
SN - 2041-6520
VL - 12
SP - 8096
EP - 8104
JO - Chemical Science
JF - Chemical Science
IS - 23
ER -