Cationic Organometallic Complexes of Scandium, Yttrium, and the Lanthanoids

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

“…Because Cp is a 5-carbon, 6-electron aromatic system, it can readily diffuse the negative charge through resonance. Therefore, cyclopentadienyls bind 7 in the review, but the list is not meant to be exhaustive since several reviews cover the area of noncyclopentadienyl rare earth chemistry (Arnold and Casely, 2009;Diaconescu, 2008;Edelmann et al, 2002;Edelmann, 2009;Konkol and Okuda, 2008;Li et al, 2010;Piers and Emslie, 2002;Reznichenko and Hultzsch, 2010;Trifonov, 2010;Zeimentz et al, 2006). Fryzuk and co-workers pioneered the use of multidentate amidophosphine ligands, which combine soft phosphine and hard amide donors, and incorporated such motifs into the coordination sphere of group 3 metals, including the tridentate [N(SiMe2CH2P i Pr2)2] -(P2N) in (P2N)ScR2 (R = Me, Et, CH2SiMe3) (Fryzuk et al, 1996), tetradentate (PhP[CH2(SiMe2)N(SiMe2)CH2]2PPh) 2-(P2N2) in (P2N2)Y[CH(SiMe3)2] (Fryzuk et al, 1997), and, recently, the tetradentate fc(NP i Pr2)2 in [(fc(NP i Pr2)2)Sc(THF)(-H)]2 (Halcovitch and Fryzuk, 2013).…”

CH Activation versus Yttrium–Methyl Cation Formation from [Y(AlMe4)3] Induced by Cyclic Polynitrogen Bases: Solvent and Substituent‐Size Effects

“…Consequently, non-solvated rare-earth-metal-methyl complexes were classified as the most reactive organolanthanide compounds. [9] The trianionic hexamethylate complexes [LnA C H T U N G T R E N N U N G {(m-Me) 2 Li(L)} 3 ] (L= N,N,N',N'-tetramethyl-1,2-ethane or 1,2-dimethoxyethane), first reported by Schumann and co-workers, [10] 4 ] by way of the in situ generated, THF-solvated analogue [LnA C H T U N G T R E N N U N G {(mMe) 2 LiA C H T U N G T R E N N U N G (thf) n } 3 ]. [4,11] The tris(tetramethylaluminates) of the rare-earth metals, first reported by Evans et al, [12] have also been used for this purpose.…”

“…[1] This field had been dominated by neutral and anionic complexes, but the interest in cationic species is steadily growing because they have shown to be versatile catalysts in a-olefin polymerisation and cognate processes. [2] Monocationic, rare-earth, alkyl complexes often include crown ethers as stabilising agents, for example in [LnA C H T U N G T R E N N U N G (CH 2 SiMe 3 ) 2 …”

Yttrium-Alkyl Complexes Supported by a Ferrocene-Based Phosphinimine Ligand

“…[1][2][3][4][5][6][7][8][9] In 1983, Watson reported the first yttrium(III) monoalkyl metallocene complex; 10 that report was also the first to identify a ligand exchange reaction going through a four-membered transition state identified as σ-bond metathesis. [11][12][13] Although cyclopentadienyl ligands have dominated the chemistry of yttrium alkyl complexes for a long time, [3][4][5] recently, several groups have reported the synthesis of such compounds supported by noncyclopentadienyl ligands. [14][15][16] Our group has studied extensively the reactivity of group 3 metals and uranium alkyl complexes supported by diamide ligands towards heterocyclic aromatic compounds.…”