211310-79-1Relevant academic research and scientific papers
Unsolvated lanthanide metallocene cations [(C5Me5)2Ln][BPh4]: Multiple syntheses, structural characterization, and reactivity including the formation of (C5Me5)3Nd
Evans, William J.,Seibel, Christopher A.,Ziller, Joseph W.
, p. 6745 - 6752 (1998)
Divalent (C5Me5)2Sm reacts with AgBPh4 in toluene to form [(C5Me5)2Sm][BPh4], 1, in ca. 60% yield. The solid-state structure of 1 consists of a trivalent (C5Me5)2Sm bent metallocene unit with a 2.702(3) ? average Sm-C(C5Me5) distance that is oriented toward two of the phenyl rings of the [BPh4]- anion with 2.825(3) and 2.917(3) ? Sm-C(o-Ph) distances. 1 can also be obtained from reactions of Et3NHBPh4 in arene solvents with the trivalent samarium precursors (C5Me5)2Sm[CH(SiMe3)2] (>50% yield) and (C5Me5)2Sm(η3-CH2CHC2) (2) (>95% yield). 1 reacts with LiCH(SiMe3)2 in benzene to produce (C5Me5)2Sm[CH(SiMe3)2] in over 95% yield. The reaction of 1 with KC5Me5 in benzene constitutes a new synthesis of the sterically crowded complex (C5Me5)3Sm, which is formed in over 90% yield. This reaction provides a convenient way to make (C5Me5)3Ln complexes with lanthanides which do not have a reactive divalent oxidation state. To enhance the ease of preparing (C5Me5)3Ln complexes from LnCl3, an improved synthesis of the allyl precursors (C5Me5)2Ln(η3-CH2CHCH2) (Ln = Sm (2), Nd (3), Tm (4)) is reported. 2-4 can be prepared in 60-90% yield from (C5Me5)2LnCl2K(THF)2 and ClMg(CH2CHCH2) followed by desolvation of the solids between 55 and 70°C for 4-16 h. 2-4 react with Et3NHBP4 in benzene to produce [(C5Me5)2Ln][BPh4] (Ln = Sm (1), Nd (5), Tm(6)). 5 has a solid-state structure identical to that of 1 and similarly reacts with LiCH(SiMe3)2 and KC5Me5 in benzene to produce (C5Me5)2Nd[CH(SiMe3)2 and (C5Me5)3Nd (7), respectively, in high yield. 7 was characterized by X-ray crystallography and shown to have an (η5-C5Me5)3Nd structure with a 2.86(6) ? Nd-C(C5Me5) distance. Since the allyl complexes (C5Me5)2Ln(η3-CH2CHCH2) are readily converted to the hydrides [(C5Me5)2LnH](n) by hydrogen, the improved synthesis of the allyl complexes also provides an improved route to these hydrides as demonstrated by the reaction of (C5Me5)2Nd(η3-CH2CHCH2) with H2 to form [(C5Me5)2NdH]2 in 75% yield.
