A Thorium Chalcogenolate Series Generated by Atom Insertion into Thorium–Carbon Bonds

A new thorium monoalkyl complex, Th­(CH2SiMe3)­(L3) (L = MeC­(NiPr)2) (2), undergoes insertion of chalcogen atoms resulting in a series of thorium chalcogenolate complexes, Th­(ECH2SiMe3)­(L3) (E = S, SS, Se, Te; 5–8). Complex 6 represents the first alkyl disulfide thorium species and illustrates the ability of 2 to undergo controllable, stoichiometric atom insertion. All complexes have been characterized by 1H and 13C NMR spectroscopy, FTIR, EA, and melting point, and in the case of 1, 2, and 4–8, X-ray crystallography. Insertion was achieved by balancing the thermodynamic driving force of chalcogenolate formation versus the BDE of the pnictogen–chalcogen bond in the transfer reagent. Utilizing Me3NO as an oxygen atom transfer reagent led to C–H activation and SiMe4 extrusion rather than oxygen atom insertion, resulting in the alkoxide complex Th­(OCH2NMe2)­(L3) (4).