Synthesis and reactivity of a terminal uranium(iv) sulfide supported by siloxide ligands. Issue 9 (2nd June 2016)

• Record Type: Journal Article
• Authors: Andrez, Julie; Pécaut, Jacques; Scopelliti, Rosario; Kefalidis, Christos E.; Maron, Laurent; Rosenzweig, Michael W.; Meyer, Karsten; Mazzanti, Marinella
• Is Part Of: Chemical science. Volume 7:Issue 9(2016:Sep.)
• Page Start: 5846
• Page End: 5856
• Publication Date: 2016-06-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6sc00675b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The S-transfer reaction from Ph3 PS to the tetrasiloxide U(iii ) complex [U(OSi(O t Bu)3 )4 K] affords a stable U(iv ) triply bonded terminal sulfide that can be protonated to yield a U(iv ) doubly bonded terminal hydrosulfide. Abstract : The reactions of the tetrasiloxide U(iii ) complexes [U(OSi(O t Bu)3 )4 K] and [U(OSi(O t Bu)3 )4 ][K18c6] with 0.5 equiv. of triphenylphosphine sulfide led to reductive S-transfer reactions, affording the U(iv ) sulfide complexes [SU(OSi(O t Bu)3 )4 K2 ]2, 1, and [{SU(OSi(O t Bu)3 )4 K2 }2 (μ-18c6)], 2, with concomitant formation of the U(iv ) complex [U(OSi(O t Bu)3 )4 ]. Addition of 1 equiv. of 2.2.2-cryptand to complex1 resulted in the isolation of a terminal sulfide complex, [SU(OSi(O t Bu)3 )4 K][Kcryptand], 3 . The crucial role of the K + Lewis acid in these reductive sulfur transfer reactions was confirmed, since the formation of complex3 from the reaction of the U(iii ) complex [U(OSi(O t Bu)3 )4 ][Kcryptand] and 0.5 equiv. of PPh3 S 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(O t Bu)3 )4 ][K18c6]}, 5, after protonation with PyHCl. Finally, DFT calculations were performed to investigate the nature of the U–S bond in complexes1, 3 and5 . Based on various analyses, triple-bond character was suggested for the U–S bond in complexes1 and3, while double-bond character was determined for the U–SH bond in complex5 .