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Synthesis, structure, and reactivity of uranium(vi) nitrides
Uranium nitride compounds are important molecular analogues of uranium nitride materials such as UN and UN(2) which 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 bond...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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The Royal Society of Chemistry
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208130/ https://www.ncbi.nlm.nih.gov/pubmed/34194699 http://dx.doi.org/10.1039/d1sc01796a |
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author | Barluzzi, Luciano Hsueh, Fang-Che Scopelliti, Rosario Atkinson, Benjamin E. Kaltsoyannis, Nikolas Mazzanti, Marinella |
author_facet | Barluzzi, Luciano Hsueh, Fang-Che Scopelliti, Rosario Atkinson, Benjamin E. Kaltsoyannis, Nikolas Mazzanti, Marinella |
author_sort | Barluzzi, Luciano |
collection | PubMed |
description | Uranium nitride compounds are important molecular analogues of uranium nitride materials such as UN and UN(2) which 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(t)Bu)(3))(3)(μ-N)}(2)], 1, with mild oxidants yields the U(v)/U(vi) complexes [K{U(OSi(O(t)Bu)(3))(3)(μ-N)}(2)], 2 and [K(2){U(OSi(O(t)Bu)(3))(3)}(2)(μ-N)(2)(μ-I)], 3 while oxidation with a stronger oxidant (“magic blue”) yields the U(vi)/U(vi) complex [{U(OSi(O(t)Bu)(3))(3)}(2)(μ-N)(2)(μ-thf)], 4. The three complexes show very different stability and reactivity, with N(2) release observed for complex 4. Complex 2 undergoes hydrogenolysis to yield imido bridged [K(2){U(OSi(O(t)Bu)(3))(3)(μ-NH)}(2)], 6 and rare amido bridged U(iv)/U(iv) complexes [{U(OSi(O(t)Bu)(3))(3)}(2)(μ-NH(2))(2)(μ-thf)], 7 while no hydrogenolysis could be observed for 4. Both complexes 2 and 4 react with H(+) to yield quantitatively NH(4)Cl, but only complex 2 reacts 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 for 1 and 2, but an asymmetric bonding scheme is found for the U(vi)/U(vi) complex 4 which shows a U–N σ orbital well localised to U[triple bond, length as m-dash]N and π orbitals which partially delocalise to form the U–N single bond with the other uranium. |
format | Online Article Text |
id | pubmed-8208130 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-82081302021-06-29 Synthesis, structure, and reactivity of uranium(vi) nitrides Barluzzi, Luciano Hsueh, Fang-Che Scopelliti, Rosario Atkinson, Benjamin E. Kaltsoyannis, Nikolas Mazzanti, Marinella Chem Sci Chemistry Uranium nitride compounds are important molecular analogues of uranium nitride materials such as UN and UN(2) which 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(t)Bu)(3))(3)(μ-N)}(2)], 1, with mild oxidants yields the U(v)/U(vi) complexes [K{U(OSi(O(t)Bu)(3))(3)(μ-N)}(2)], 2 and [K(2){U(OSi(O(t)Bu)(3))(3)}(2)(μ-N)(2)(μ-I)], 3 while oxidation with a stronger oxidant (“magic blue”) yields the U(vi)/U(vi) complex [{U(OSi(O(t)Bu)(3))(3)}(2)(μ-N)(2)(μ-thf)], 4. The three complexes show very different stability and reactivity, with N(2) release observed for complex 4. Complex 2 undergoes hydrogenolysis to yield imido bridged [K(2){U(OSi(O(t)Bu)(3))(3)(μ-NH)}(2)], 6 and rare amido bridged U(iv)/U(iv) complexes [{U(OSi(O(t)Bu)(3))(3)}(2)(μ-NH(2))(2)(μ-thf)], 7 while no hydrogenolysis could be observed for 4. Both complexes 2 and 4 react with H(+) to yield quantitatively NH(4)Cl, but only complex 2 reacts 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 for 1 and 2, but an asymmetric bonding scheme is found for the U(vi)/U(vi) complex 4 which shows a U–N σ orbital well localised to U[triple bond, length as m-dash]N and π orbitals which partially delocalise to form the U–N single bond with the other uranium. The Royal Society of Chemistry 2021-04-30 /pmc/articles/PMC8208130/ /pubmed/34194699 http://dx.doi.org/10.1039/d1sc01796a Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Barluzzi, Luciano Hsueh, Fang-Che Scopelliti, Rosario Atkinson, Benjamin E. Kaltsoyannis, Nikolas Mazzanti, Marinella Synthesis, structure, and reactivity of uranium(vi) nitrides |
title | Synthesis, structure, and reactivity of uranium(vi) nitrides |
title_full | Synthesis, structure, and reactivity of uranium(vi) nitrides |
title_fullStr | Synthesis, structure, and reactivity of uranium(vi) nitrides |
title_full_unstemmed | Synthesis, structure, and reactivity of uranium(vi) nitrides |
title_short | Synthesis, structure, and reactivity of uranium(vi) nitrides |
title_sort | synthesis, structure, and reactivity of uranium(vi) nitrides |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208130/ https://www.ncbi.nlm.nih.gov/pubmed/34194699 http://dx.doi.org/10.1039/d1sc01796a |
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