Brackbill I Joseph, Douair Iskander, Lussier Daniel J, Boreen Michael A, Maron Laurent, Arnold John
Department of Chemistry, University of California, Berkeley, and the Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720-1460, USA.
LPCNO, Université de Toulouse, INSA Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France.
Chemistry. 2020 Feb 21;26(11):2360-2364. doi: 10.1002/chem.202000214. Epub 2020 Feb 4.
While carbene complexes of uranium have been known for over a decade, there are no reported examples of complexes between an actinide and a "heavy carbene." Herein, we report the syntheses and structures of the first uranium-heavy tetrylene complexes: (CpSiMe ) U-Si[PhC(NR) ]R' (R=tBu, R'=NMe 1; R=iPr, R'=PhC(NiPr) 2). Complex 1 features a kinetically robust uranium-silicon bonding interaction, while the uranium-silicon bond in 2 is easily disrupted thermally or by competing ligands in solution. Calculations reveal polarized σ bonds, but depending on the substituents at silicon a substantial π-bonding interaction is also present. The complexes possess relatively high bond orders which suggests primarily covalent bonding between uranium and silicon. These results comprise a new frontier in actinide-heavy main-group bonding.
