A binuclear thorium complex with a Th–O–Th unit

Abstract

Complex 1, [(Trapen^TMS)ThCl, Trapen^TMS = N(CH₂Ph(o-NSiMe₃)₃)], reacts with sodium azide to afford the dimeric complex 2, [(Trapen^TMSN₃Th)₂]. Treatment of 2 with KC₈ yields a binuclear oxo-bridged thorium complex 3, [(Trapen^TMSTh)₂(µ-O)]. The crystal structure of 3 reveals a highly symmetrical configuration with a Th–O–Th unit, and the Th–O bond length is 2.271(2) Å. Density functional theory calculations indicate significant covalent character in the Th–O–Th interaction, surpassing that in related Th–N–Th systems and the Th–O bonding in complex 3 displays stronger covalent interactions.