Single and Double Alkyl Abstraction from a Bis(anilido)xanthene Thorium(IV) Dibenzyl Complex: Isolation of an Organothorium Cation and a Thorium Dication

Abstract

Reaction of [(XA2)ThCl2(dme)] [XA2 = 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene] with 2 equiv of PhCH2MgCl resulted in the formation of solvent-free [(XA2)Th(CH2Ph)2] (1). Subsequent reaction of 1 with either 1 or 2 equiv of B(C6F5)3 allowed isolation of the first non-cyclopentadienyl actinide alkyl cation, [(XA2)Th(CH2Ph)][PhCH2B(C6F5)3] (2), and a rare example of an actinide dication, [(XA2)Th][PhCH2B(C6F5)3]2 (3). The X-ray crystal structure of the dication reveals π-coordination of both PhCH2B(C6F5)3 anions, and solution NMR spectroscopy shows that a similar mode of contact ion pairing is operative in the monocation.