Cyclopentadienyl and phospholyl compounds in organometallic actinide chemistry

Heteroleptic Rare Earth Tetraalkylphospholide Cyclooctatetraenide Sandwich Complexes

“…Cyclopentadienide (Cp, {C5H5} -) and cyclooctatetraenide (COT, {C8H8} 2-) complexes are ubiquitous in rare-earth and actinide organometallic chemistry, [1][2][3][4][5] and have delivered landmark advances in metal-metal bonding [6][7][8][9] , molecular magnetism [9][10][11][12][13] , and small molecule activation [14][15][16][17] (Figure 1 A-D for some exemple complexes). Parent Cp and substituted derivatives, Cp R , {C5R5}, also find extensive use as inert spectator ligands in catalysts due to their ability to saturate coordination spheres and support additional functionality as required [18][19][20][21] .…”

Back to the future of organolanthanide chemistry

“…6 This particular feature has been later explained by Denning et al 21 and relates to an unusual intermediate valent electronic structure for these, in appearance only, simple molecules. The size mismatch between the small cyclopentadienyl ligand and the large metallic f-elements has been easily corrected by increasing the size of the aromatic ligand used, either by substituting the hydrogens with bulkier groups 23,24 or using larger aromatic rings. 25,26 Both methods proved very efficient in accessing sandwich compounds of various charges and oxidation states with f-elements.…”

Phenylsilyl-Substituted Tetramethylcyclopentadienide Uranium Chemistry: Magnesocenes vs Grignard Reagents

“…The organometallic chemistry of the f -elements has benefited greatly from the use of cyclopentadienyl ligands, which can be readily functionalized with substituents that provide different steric and electronic profiles. − The f -element cyclopentadienyl complexes are typically synthesized from the metal halides and lithium, sodium, or potassium cyclopentadienyl salts. − However, in the case of the commonly studied bis­(cyclopentadienyl) uranium dihalide complex, (C 5 Me 5 ) 2 UCl 2 , − synthesis from UCl 4 and one equivalent of the Grignard reagent, [(C 5 Me 5 )­MgCl­(THF)] 2 , , in refluxing toluene is more common than reactions with reagents such as LiC 5 Me 5 and KC 5 Me 5 . This mode of synthesis was extended to the trimethylsilyltetramethyl-substituted analogue, [C 5 Me 4 (SiMe 3 )] 2 UCl 2 , which was synthesized using [C 5 Me 4 (SiMe 3 )]­MgCl­(THF) rather than KC 5 Me 4 (SiMe 3 ) .…”