Actinide Pnictinidene Chemistry: A Terminal Thorium Parent‐Arsinidene Complex Stabilised by a Super‐Bulky Triamidoamine Ligand
Jingzhen Du, Gábor Balázs, John A. Seed, Jonathan D. Cryer, Ashley J. Wooles, Manfred Scheer, Stephen T. Liddle
Abstract
Abstract We report the direct synthesis of the terminal pnictidenes [An(Tren TCHS )(PnH)][M(2,2,2‐cryptand)] (Tren TCHS ={N(CH 2 CH 2 NSiCy 3 ) 3 } 3− ; An/Pn/M=Th/P/Na 5 , Th/As/K 6 , U/P/Na 7 , U/As/K 8 ) and their conversion to the pnictides [An(Tren TCHS )(PnH 2 )] (An/Pn=Th/P 9 , Th/As 10 , U/P 11 , U/As 12 ). Use of the super‐bulky Tren TCHS ligand was essential to accessing complete families, and 6 is an unprecedented example of a terminal thorium‐arsinidene complex and only the second structurally authenticated parent terminal arsinidene complex of any metal. Comparison of the terminal Th=AsH unit of 6 to the bridging ThAs(H)K linkage in structurally analogous [Th(Tren TIPS ){μ‐As(H)K(15‐crown‐5)}] (Tren TIPS ={N(CH 2 CH 2 NSiPr i 3 ) 3 } 3− ) reveals a stronger Th−As bond in the former compared to the latter, and a large response overall to the nature of the Th=AsH bonding upon removal of the electrostatically‐bound K‐ion; the σ‐bond changes little but the π‐bond is significantly perturbed.