Issue 9, 2016

Synthesis and reactivity of a terminal uranium(iv) sulfide supported by siloxide ligands


The reactions of the tetrasiloxide U(III) complexes [U(OSi(OtBu)3)4K] and [U(OSi(OtBu)3)4][K18c6] with 0.5 equiv. of triphenylphosphine sulfide led to reductive S-transfer reactions, affording the U(IV) sulfide complexes [SU(OSi(OtBu)3)4K2]2, 1, and [{SU(OSi(OtBu)3)4K2}2(μ-18c6)], 2, with concomitant formation of the U(IV) complex [U(OSi(OtBu)3)4]. Addition of 1 equiv. of 2.2.2-cryptand to complex 1 resulted in the isolation of a terminal sulfide complex, [SU(OSi(OtBu)3)4K][Kcryptand], 3. The crucial role of the K+ Lewis acid in these reductive sulfur transfer reactions was confirmed, since the formation of complex 3 from the reaction of the U(III) complex [U(OSi(OtBu)3)4][Kcryptand] and 0.5 equiv. of PPh3S was not possible. Reactivity studies of the U(IV) sulfide complexes showed that the sulfide is easily transferred to CO2 and CS2 to afford S-functionalized products. Moreover, we have found that the sulfide provides a convenient precursor for the synthesis of the corresponding U(IV) hydrosulfide, {[(SH)U(OSi(OtBu)3)4][K18c6]}, 5, after protonation with PyHCl. Finally, DFT calculations were performed to investigate the nature of the U–S bond in complexes 1, 3 and 5. Based on various analyses, triple-bond character was suggested for the U–S bond in complexes 1 and 3, while double-bond character was determined for the U–SH bond in complex 5.

Graphical abstract: Synthesis and reactivity of a terminal uranium(iv) sulfide supported by siloxide ligands

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Article information

Article type
Edge Article
13 Feb 2016
08 Apr 2016
First published
10 May 2016
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2016,7, 5846-5856

Synthesis and reactivity of a terminal uranium(IV) sulfide supported by siloxide ligands

J. Andrez, J. Pécaut, R. Scopelliti, C. E. Kefalidis, L. Maron, M. W. Rosenzweig, K. Meyer and M. Mazzanti, Chem. Sci., 2016, 7, 5846 DOI: 10.1039/C6SC00675B

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