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

Abstract

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).