Systematic investigation of thorium(IV)- and uranium(IV)-ligand bonding in dithiophosphonate, thioselenophosphinate, and diselenophosphonate complexes

摘要

Homoleptic soft-donor actinide complexes of the general form An[E _2PROR′]_4 were synthesized from salt metathesis between ThCl_4(DME)_2 or UI_4(1,4-dioxane) _2 and M[E_2PROR′], M = Na, K, to yield 2 (An = Th, E = S, R = 4-MeOC_6H_4, R′ = Me), 3 (An = Th, E = S, R = 4-MeOC_6H_4, R′ = ~~tBu), 4 (An = U, E = S, R = 4-MeOC_6H_4, R′ = Me), 5 (An = Th, E = Se, R = C_6H_5, R′ = Me), and 6 (An = U, E = Se, R = C _6H_5, R′ = Me). In addition thorium and uranium thioselenophosphinate complexes 7 and 8 were produced from the reaction of ThCl_4(DME)_2 and UI_4(1,4-dioxane)_2 and Na[SSePPh_2], respectively. All compounds were characterized using elemental analysis, ~1H and ~(31)P NMR, and IR spectroscopy, and the U(IV) compounds were also examined with thioselenophosphinate spectroscopy. The ~(77)Se NMR spectrum of 5 reveals the first reported resonance with a Th-Se bond. The solid-state structures of 2, 5, 7, and 8 were determined by X-ray crystallography. The actinide-ligand bonding was examined using density functional theory calculations in conjunction with quantum theory of atoms-in-molecules analysis and shows slightly increased covalency in actinide-selenium bonds than actinide-sulfur.