A Direct Route to Bis(imido)uranium(V) Halides via Metathesis of Uranium Tetrachloride

Abstract

Metathesis reactions between uranium tetrachloride and lithium 2,6-diisopropylphenylamide in the presence of 4,4'-dialkyl-2,2'-bipyridyl (R(2)bpy; R = Me, (t)Bu) or triphenylphosphine oxide (tppo) appear to generate bis(imido)uranium(IV) in situ. These extremely reactive complexes abstract chloride from dichloromethane to generate U(NDipp)(2)Cl(R(2)bpy)(2) or U(NDipp)(2)Cl(tppo)(3) (Dipp = 2,6-(i)Pr(2)C(6)H(3)). The preparation of the bromide and iodide analogues U(NDipp)(2)X(R(2)bpy)(2) was achieved by addition of CH(2)X(2) (X = Br, I) to the uranium(IV) solutions. The uranium(V) halides were characterized by X-ray crystallography and found to exhibit linear N-U-N units and short U-N bonds. Electrochemical measurements were made on the chloride bipyridine species, which reacts readily with iodine or ferrocenium to generate bis(imido)uranium(VI) cations.

Thorium–phosphorus triamidoamine complexes containing Th–P single- and multiple-bond interactions

“…This desire stems not only from a need to develop our knowledge and understanding of actinide bonding at a fundamental level45678, but also because of potential applications in nuclear waste clean-up which might utilize extraction methods that exploit covalency differences in metal-ligand bonding9. Because actinide-ligand multiple bonds arguably contain the greatest opportunities to probe covalency101112, in recent years in addition to numerous oxo complexes12 there has been intensive progress in uranium-carbene13141516171819, -imido202122232425262728, -nitride29303132, -phosphinidene/-arsinidene/-arsenido33343536 and -chalcogenido (S, Se, Te) chemistry37383940. This work demonstrates the wide range of multiply bonded ligands that can be stabilised at uranium with appropriate supporting ligands, and also that softer, heavier main group element centres can be stabilised as well as relatively hard first-row elements such as C, N and O.…”

Synthesis and Reduction of Uranium(V) Imido Complexes with Redox‐Active Substituents

“…[4][5][6][7][8] The studyo fU À Nm ultiple bondingi sm ore limited, although it has recently achieved milestone discoveries in the isolation of the first exampleso ft erminal molecular uranium nitride, [9][10][11] terminal parenti mido, [12] and uranium tris(imido) moieties. [13,14] Presently,t here are an umber of high-valent uraniumb is(imido) complexes reported in the literature, [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] as well as uranium mono(imido)c omplexes in the uranium + 4, [24][25][26][27][28][29][30][31][32][33][34][35] + 5, [36][37][38][42][43][44][45][46] and + 6 [36,37,…”

Triamidoamine uranium(IV)–arsenic complexes containing one-, two- and threefold U–As bonding interactions

“…Uranium is one actinide that is amenable to routine study, and uranium-ligand multiple-bond complexes have attracted attention because they would be expected to contain some covalency 13-15 . Recently, in addition to the numerous uranium-oxo derivatives, for example uranyl 16 , there have been advances in the synthesis, characterization and understanding of covalent, terminal uraniumcarbene [17][18][19][20][21][22] , -imido [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] , -nitride [38][39][40] , -phosphinidene [41][42][43] and heavier-chalcogenide 44,45 multiple bonds. Nevertheless, carbon, nitrogen and oxygen donor ligands dominate, and post-first-row donor ligands remain relatively rare and sharply decrease in number as the periodic table is descended.…”