Pentamethylcyclopentadienyl-Supported Rare-Earth-Metal Benzyl, Amide, and Imide Complexes

Abstract

The half-sandwich diiodide complexes [Cp*­LnI2] x (Ln = Y, Lu), obtained in high yields from Cp*Ln­(AlMe4)2 (Cp*= C5Me5) and 2 equiv of ISiMe3, reacted with 2 equiv of potassium benzyl KCH2Ph in THF to afford complexes Cp*Ln­(CH2Ph)2­(thf). Protonolysis of Cp*Ln­(CH2Ph)2­(thf) with 3,5-bis­(trifluoro­methyl)­aniline (H2N­C6H3­(CF3)2-3,5 = H2NArCF3) in toluene gave rare-earth-metal imide complexes [Cp*Ln­(NC6H3­(CF3)2-3,5)­(thf) x ]2 (Ln = Y (x = 2), Lu (x = 1)). The dimeric structure of [Cp*Ln­(NC6H3­(CF3)2-3,5)­(thf) x ]2 with two bridging imido ligands forming a planar Ln2N2 core was analyzed by X-ray crystallography. Treatment of Cp*Y­(CH2Ph)2­(thf) with H2N­C6H3­(CF3)2-3,5 in THF led to the monomeric bis­(amide) complex Cp*Y­(NH­C6H3­(CF3)2-3,5)2­(thf)2. The reaction of Cp*Y­(CH2Ph)2­(thf) with 2,6-diisopropyl­aniline in toluene gave also the bis­(amide) complex Cp*Y­(NH­C6H3­iPr2-2,6)2­(thf), whereas, in a THF solution, the formation of the labile mixed benzyl amide complex Cp*Y­(HN­C6H3­iPr2-2,6)­(CH2Ph)­(thf) was observed.

Potential Precursors for Terminal Methylidene Rare‐Earth‐Metal Complexes Supported by a Superbulky Tris(pyrazolyl)borato Ligand

“…Other rare solid‐state structures of monomeric but heteroleptic Tp‐based rare‐earth‐metal complexes as [Tp R,R Ln(Danip)(CH 2 SiMe 3 )] (R=Me or R=H, Ln=Yb, Danip=2,6‐di( o ‐anisol)phenyl)) display similar bond lengths (Yb−C ipso : 2.414(3)–2.438(4)/2.402(4)–2.435(5) Å; Yb−C(neosilyl): 2.379(4)–2.392(4)/2.359(4)–2.368(4) Å) taking into account the metal‐ion size [33] . The Lu−C(benzyl) bond length (2.412(3) Å) in 9‐Lu matches that in Lu(CH 2 Ph) 3 (THF) 3 [34] (2.404(7)–2.413(5) Å) and Lu(CH 2 Ph) 3 (THF) 2 (2.380(3)–2.404(3) Å) [35] but is slightly elongated compared with Cp*Lu(CH 2 Ph) 2 (THF) (2.378(2)–2.386(2) Å; Cp*=C 5 Me 5 ) [36] . Furthermore, there is no significant secondary interaction between Lu1 and the ipso carbon atom C27 for 9‐Lu , as suggested by the Lu1⋅⋅⋅C27 distance of 3.314 Å and the Lu‐C(CH 2 )‐C27 angle (114.3(2)°).…”

“…2019,25,[14711][14712][14713][14714][14715][14716][14717][14718][14719][14720] www.chemeurj.org (3) )i n9-Lu matches that in Lu(CH 2 Ph) 3 (THF) 3 [34] (2.404(7)-2.413(5) )a nd Lu(CH 2 Ph) 3 (THF) 2 (2.380(3)-2.404(3) ) [35] but is slightly elongatedc ompared with Cp*Lu(CH 2 Ph) 2 (THF) (2.378(2)-2.386(2) ;C p* = C 5 Me 5 ). [36] Furthermore, there is no significant secondary interaction between Lu1 andt he ipso carbon atom C27 for 9-Lu,a ss uggested by the Lu1···C27 distance of 3.314 and the Lu-C(CH 2 )-C27 angle (114.3(2)8). For further comparison, complex [Tp Me,Me Y(CH 2 Ph) 2 (THF)] was obtained through salt metathesis from [Tp Me,Me YCl 2 (THF) 2 ]a nd potassium benzyl( Y ÀC(CH 2 ) 2.457(8) and 2.418(8) ,Y -CH 2 -C ipso 116.4(6) and 130.1(6)8).…”

Open-Shell Early Lanthanide Terminal Imides

“…The initial step involves the first protonation of the methylidene moiety by the arylamine, generating mixed methyl/amide intermediate I 1 upon the release of one molecule of [GaMe 3 ]. Compounds similar to I 1 have been isolated and structurally characterized in the presence of cyclopentadienyl ancillary ligands. ,, A second equivalent of the amine affords a bis­(amido) complex as shown for 9-Nd . In the absence of additional amine, the reaction progress is crucially affected by the 2,6-substitution pattern of the arylamine and the size of Ln­(III).…”

“…Compounds similar to I 1 have been isolated and structurally characterized in the presence of cyclopentadienyl ancillary ligands. 27,40,45 A second equivalent of the amine affords a bis(amido) complex as shown for 9-Nd. In the absence of additional amine, the reaction progress is crucially affected by the 2,6-substitution pattern of the arylamine and the size of Ln(III).…”

A Rare-Earth-Metal Ensemble of the Tebbe Reagent: Scope of Coligands and Carbonyl Olefination

“…A closer look at this apparent discrepancy between solid-state analytics and NMR solution measurements indicated the occurrence of ligand redistribution in aromatic solvents over time (Scheme ). Such intermolecular ligand exchange would involve the coformation of putative [Cp R LnX 2 ], , but the hardly soluble byproducts were not further characterized. Furthermore, the true nature of the composition of the complexes 1-Ln X was validated with elemental analysis as well as various unit-cell checks confirming that the products 1-Ln X crystallized from the mother liquor in n -hexane as the exclusive product when they were not redissolved in aromatic solvents.…”