Ytterbium complexes cyclopentadienyl compounds

The binuclear samarium and ytterbium complexes with mixed valence of Ln(II, IQ) (Me5C5)2Sm( i-Cp)Sm(C5Me5)2 [37] and (Me5C5)2Yb(ji-F)Yb(C5Me5)2 [46], are close to the being considered class of compounds in their nature. The complex with cyclopentadienyl bridge can be isolated from the mixture containing cyclopentadiene and... 

Recrystallization of the linked cyclopentadienyl-anilido ytterbium(ll) complex [Me2Si(CsMe4)(NPh)]Yb(THF)3 from toluene/hexane yielded the less solvated complex [ Me2Si(CsMe4)(NPh) Ln(THF)]2 as brown crystals in 91% yield (Scheme 219). The compound forms a dimeric structure through an intermolecular Yb-Ph 7r-interaction. 

Watson (1980), Watson et al. (1981) and TiUey and Andersen (1981b) prepared bis(pentamethylcyclopentadienyl) ytterbium, lutetium, neodymium and samarium chlorides and iodides. Some physical data of these compounds together with those of the other complexes with substituted cyclopentadienyl ligands are given in table 8. The following synthetic methods have been used ytterbium metal is oxidized by CjMejI in the presence of Lil in ether to give, via CjMejYbl, the complexes shown in eq. (20). In the absence of Lil, only dimeric pentamethylcyclopentadiene was isolated. 

Cyclopentadienyl complexes of lanthanoids(II) are known for samarium, europium and ytterbium [1-24] (Table III.L) One compound of Nd(II) is claimed as well [25], but its exact structure and the valent state of the neodymium atom apparently needs additional proves. Samarium derivatives are isolated as tetrahydrofuranates Cp2Sm(THF). In the case of europium and ytterbium solvent-free complexes are obtained. 

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