Achievements in uranium alkyl chemistry: celebrating sixty years of synthetic pursuits

Abstract

Organouranium complexes containing uranium-carbon σ-bonds have been highly sought after since the initial exploration of these complexes during the 1950s. Since this time, a variety of uranium starting materials have been developed and alkylating reagents used in order to generate such species. Trivalent uranium alkyl compounds have recently moved past using the bis(trimethylsilyl)methyl ligand with the use of larger ancillary hydrotris(pyrazolyl)borate ligands. The uranium(iv) congeners are dominated by cyclopentadienyl ligands, but recent developments have shown that amides, alkoxides, and phosphines are also suitable ligand frameworks for supporting such species. A family of uranium(iv) alkyls formed via cyclometallation and neutral homoleptics have also been described. Highly reactive uranium(v) and (vi) alkyl complexes have recently been synthesized at low temperatures. The representative studies highlighted herein have helped to pioneer the field of organouranium alkyl chemistry.

Collision‐induced dissociation of uranyl‐methoxide and uranyl‐ethoxide cations: Formation of UO 2 H + and uranyl‐alkyl product ions

“…The apparent formation of [UO 2 CH 3 ] + from CID of [UO 2 OCH 2 CH 3 ] + is particularly interesting. Species that contain uranyl–carbon bonds are relatively rare, presumably due to the reduction of UO 2 2 + to UO 2 + by alkyl ligands . Our results suggest that [UO 2 CH 3 ] + can be generated by CID of a relatively simple precursor such as [UO 2 OCH 2 CH 3 ] + .…”

“…The apparent formation of [UO 2 CH 3 ] + from CID of [UO 2 OCH 2 CH 3 ] + is particularly interesting. Species that contain uranyl-carbon bonds are relatively rare, [44][45][46][47][48] presumably due to the reduction of UO 2 2+ to UO 2 + by alkyl ligands. [48,49] [50] Heterolytic cleavage to liberate CH 3 has also been observed following CID of metal-acetonitrile complexes, including those that contain UO 2 2+ .…”

Synthesis and Hydrolysis of Uranyl, Neptunyl, and Plutonyl Gas-Phase Complexes Exhibiting Discrete Actinide–Carbon Bonds

“…Although the organometallic chemistry of the uranyl ion is relatively underdeveloped, significant success has recently been achieved in the formation of organometallic uranyl complexes, as well as other organouranium complexes containing uranium−carbon σ bonds. 6,7 Among the reported organouranyl compounds are chelate complexes in which the U−C bond is stabilized by a superstructure involving interactions with other atoms in the ligand. 8−12 Hayton and co-workers prepared the first genuine uranyl(VI)−alkyl complex.…”

Die Renaissance der nichtwässrigen Uranchemie

“…Ein entscheidendes Ergebnis für die Actinoidchemie war 1968 der Bericht über das Uranocen [U(η 8 ‐C 8 H 8 ) 2 ] ( 16 ) und 1969 die Bestätigung der Struktur, da dieser Komplex die Diskussion über die Beteiligung von f‐Elektronen an der Metall‐Ligand‐Bindung anregte, die bis heute anhält 75. Uran‐Alkyl‐, Uran‐Cyclopentadienyl‐ und Uran‐Aren‐Komplexe wurden kürzlich sehr ausführlich beschrieben,30c,d, 32b,c und der folgende Abschnitt hebt die wichtigsten Erkenntnisse hervor.…”

“…Ein Beispiel für diesen Ansatz ist die Synthese von [U(Me)(CH 2 Ph) 3 (Me 2 PCH 2 CH 2 PMe 2 )] ( 18 ) 77. Es geht also darum, die Verknüpfung sterisch zu stabilisieren,78 und mithilfe entsprechender Hilfsliganden konnten Uranmonoalkyl und Urandialkyl‐Derivate erhalten werden 32b…”