Synthesis and Structures of the First Cationic Perfluoroaryllanthanoid(II) Complexes

• Published in: Chemistry : a European journal 2004-04, Vol.10 (7), p.1798-1804
• Main Authors: Deacon, Glen B., Forsyth, Craig M.
• Format: Article
• Language: English
• Subjects: borates; cations; Cations - chemistry; fluorinated ligands; Lanthanoid Series Elements - chemistry; lanthanoids; Models, Chemical; Models, Molecular; Molecular Structure; organometallic compounds; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200306010

Tetraphenylborate salts of solvated pentafluorophenyllanthanoid(II) cations [Ln(C6F5)(thf)n]+ (Ln=Eu, n=6 (1); Ln=Yb, n=5 (2)) were readily synthesized in high yield by reactions of ytterbium or europium with HgPh(C6F5) and Me3NHBPh4 in THF. The structures of 1⋅THF and 2 confirmed the existence of well‐separated ions and both 1 and 2 show notable thermal stability at room temperature. The cation in 2 was also observed in the remarkable mixed‐valent complex [YbII(C6F5)(thf)5][YbIII(C6F5)2{N(SiMe3)2}2] (3), fortuitously isolated in low yield from a reaction of ytterbium metal, HgPh(C6F5), and HN(SiMe3)2 in THF, and which additionally has an unusual bis(pentafluorophenyl)bis{bis(trimethylsilyl)amido)}ytterbate(III) anion. 171Yb–19F coupling has been observed in the low‐temperature 171Yb NMR spectra of 2 and [Yb(C6F5)2(thf)4]. A one‐pot reaction provides a simple route to novel tetraphenylborate salts of organolanthanoid(II) cations [Ln(C6F5)(thf)n]+ (e.g. 1). These organolanthanoid(II) cations show remarkable stability, even forming part of a fortuitously isolated mixed‐valent cation/anion pair (e.g. 2).