Synthesis and Reactivity of Bis(phospholyl)neodymium(III) and -samarium(III) Chlorides and Alkyl Derivatives

Abstract

The reaction of 2,3,4,5‐tetramethylphospholylpotassium [C4Me4PK] with [LnCl3(THF)x] (Ln = Nd, Sm) in a 2:1 ratio gave unsolvated ate complexes of the formula [(C4Me4P)2LnCl2K]. Crystallisation of the samarium complex from ether afforded a polymeric ether solvate: {[(η5‐C4Me4P)Sm(μ3‐Cl)2(μ:η5,η1‐C4Me4P)K(Et2O)]∞}, which was characterised by X‐ray crystallography. Reaction of [(C4Me4P)2LnCl2K] with [LiCH(SiMe3)2] in toluene gave the alkyl complexes [(C4Me4P)2LnCH(SiMe3)2]; these complexes were most efficiently prepared from [LnCl3(THF)x], [KC4Me4P] and [LiCH(SiMe3)2] in a one‐pot procedure. Reaction of [(C4Me4P)2LnCH(SiMe3)2] with molecular hydrogen gave [(C4Me4P)2NdH], when Ln = Nd, whereas, when Ln = Sm, reduction occurred and the already known [(C4Me4P)2Sm] was isolated instead.

Heterocyclopentadienyl Complexes of Group-3 Metals

“…For instance, classical Ln III ate complexes such as [(η 5 -Tmp) 2 LnCl 2 Li(solv) 2 ] [9] [Ln ϭ Y, Lu, solv ϭ Et 2 O, dimethoxyethane (DME)] or [(η 5 -Tmp) 2 LnCl 2 K] (Ln ϭ Nd, Sm) [10] have been prepared by the reaction of the appropriate alkali metal phospholide with LnCl 3 . In the case of [(η 5 -Tmp) 2 YCl 2 Li(Et 2 O) 2 ], it has been possible to observe the coupling of 31 P with 89 Y by NMR.…”

Heteroleptic Rare Earth Tetraalkylphospholide Cyclooctatetraenide Sandwich Complexes

“…{C5-nR5-nEn} where E is a heteroatom), such as phosphorus [40,41] . The chemistry of rare earth and actinide complexes supported by (mono)phospholide ligands, {PC4R4}, remains poorly developed with only 80 such structurally characterised examples in the CCDC by June 2024 [42] , the vast majority of which has been undertaken by Nief, Mathey, Le Floch, and co-workers who contributed seminal results in the research area [42][43][44][45][46][47][48][49][50][51] . The chemistry of {PC4R4} ligands complements, but is divergent from, that of their Cp counterparts (Figure 1 E) [52] .…”

f‐Block Phospholyl and Arsolyl Chemistry

“…Several other heteroleptic Ln III Tmp chloride complexes have been reported in the interim (Figure 12). In 1999, Nief and co‐workers prepared the ‘ate’ complexes [Ln(Tmp) 2 Cl 2 K] (Ln=Nd, Sm) by the separate reactions of parent LnCl 3 (THF) n with two equivalents of K(Tmp) in THF; recrystallisation of the Sm analogue from diethyl ether allowed the solid‐state structure of [Sm(η 5 ‐Tmp)(μ:η 5 ,η 1 ‐Tmp)(μ 3 ‐Cl) 2K( Et 2 O)] ∞ ( 34 ) to be determined [35] . Complexes [Ln(Tmp) 2 Cl 2 K] were characterised by 31 P NMR spectroscopy (Ln=Nd, δ P : 459 ppm; Ln=Sm, δ P : 49.7 ppm).…”

“…In 2006, Tilley and co‐workers reported the synthesis of [Sc(η 5 ‐Tmp) 2 (μ‐Cl) 2 Li(TMEDA)] ( 35 , TMEDA = N , N , N ’, N ’‐tetramethylethylenediamine) by the reaction of ScCl 3 (THF) 3 with two equivalents of Li(Tmp)(TMEDA) in toluene [36] . The 31 P NMR spectrum of 35 exhibits one signal at 99.8 ppm, and the local structure about Sc III in the solid state is comparable to the Sm III centre in 34 , [35] although the alteration of coordinating solvent, alkali metal and Ln III ion enforces a monomeric structure at 35 (Sc−P: 2.694(2) and 2.718(2) Å) [36] . The separate reactions of 35 with LiCp* or Sc(Cp*)(Cl) 2 with Li(Tmp)(TMEDA) both gave reaction mixtures with signals in their 31 P NMR spectra at 100.2 ppm, which the authors ascribed to the mixed Cp*/Tmp complex [Sc(Cp*)(Tmp)(μ‐Cl) 2 Li(TMEDA)], although this product was not structurally authenticated.…”

“…In 1999, Nief et al. reported the syntheses of the bis‐phospholyl complexes [Ln(Tmp) 2 {CH(SiMe 3 ) 2 }] (Ln=Nd, Sm), with the most efficient synthetic route being the sequential salt metathesis reactions of parent LnCl 3 (THF) n with two equivalents of K(Tmp) followed by one equivalent of Li{CH(SiMe 3 ) 2 } in THF [35] . Although these products were not characterised by single‐crystal XRD, they each exhibited two signals in their 31 P NMR spectra ( δ P : 456 and 501 ppm for Ln=Nd; 43.4 and 46.7 ppm for Ln=Sm).…”