Bonding and Reactivity in Terminal versus Bridging Arenide Complexes of Thorium Acting as ThII Synthons

• Published in: Angewandte Chemie International Edition Vol. 62; no. 9; pp. e202215846 - n/a
• Main Authors: Hsueh, Fang‐Che, Rajeshkumar, Thayalan, Kooij, Bastiaan, Scopelliti, Rosario, Severin, Kay, Maron, Laurent, Zivkovic, Ivica, Mazzanti, Marinella
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20.02.2023
• Edition: International ed. in English
• Subjects: Actinides; Carbon dioxide; Inverse-Sandwich Complexes; Ligands; Naphthalene; Nitrous oxide; Reactivity; Redox Reactivity; Redox-Active Ligands; Reduction; Substrates; Thorium; Vinylidene
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202215846

Thorium redox chemistry is extremely scarce due to the high stability of ThIV. Here we report two unique examples of thorium arenide complexes prepared by reduction of a ThIV‐siloxide complex in presence of naphthalene, the mononuclear arenide complex [K(OSi(OtBu)3)3Th(η6‐C10H8)] (1) and the inverse‐sandwich complex [K(OSi(OtBu)3)3Th]2(μ‐η6,η6‐C10H8)] (2). The electrons stored in these complexes allow the reduction of a broad range of substrates (N2O, AdN3, CO2, HBBN). Higher reactivity was found for the complex 1 which reacts with the diazoolefin IDipp=CN2 to yield the unexpected ThIV amidoalkynyl complex 5 via a terminal N‐heterocyclic vinylidene intermediate. This work showed that arenides can act as convenient redox‐active ligands for implementing thorium‐ligand cooperative multielectron transfer and that the reactivity can be tuned by the arenide binding mode. A mononuclear arenide complex and an inverse‐sandwich complex of thorium can perform multielectron reductive chemistry with a range of substrates acting as ThII synthons. The mononuclear complex shows higher reactivity towards an diazoolefine yielding a ThIV amidoacetylido complex via a vinylidene intermediate suggesting that the Th reactivity is tuned by the arenide binding mode.