title: Neutral "Cp-Free" Silyl-Lanthanide(II) Complexes: Synthesis, Structure, and Bonding Analysis.
abstract: Complexes featuring lanthanide silicon bonds represent a research area still in its infancy. Herein, we report a series of Cp-free lanthanide (+II) complexes bearing σ-bonded silyl ligands. By reactions of LnI2 (Ln = Yb, Eu, Sm) either with a 1,4-oligosilanyl dianion [K-Si(SiMe3)2SiMe2SiMe2Si(SiMe3)2-K)] (1) or with 2 (Me3Si)3SiK (3) the corresponding neutral metallacyclopentasilanes ({Me2Si(Me3Si)2Si}2)Ln·(THF)4 (Ln = Yb (2a), Eu (2b), Sm (2c)), or the disilylated complexes ({Me3Si}3Si)2Ln·(THF)3 (Ln = Yb (4a), Eu (4b), Sm (4c)), were selectively obtained. Complexes 2b, 2c, 4b, and 4c represent the first examples of structurally characterized Cp-free Eu and Sm complexes with silyl ligands. In both series, a linear correlation was observed between the Ln-Si bond lengths and the covalent radii of the corresponding lanthanide metals. Density functional theory calculations were also carried out for complexes 2a-c and 4a-c to elucidate the bonding situation between the Ln(+II) centers and Si.
authors.affiliation: †Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Rainer
authors.initials: R
authors.lastname: Zitz
authors.affiliation: ‡Institut für Chemie, Universität Graz, Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Johann
authors.initials: J
authors.lastname: Hlina
authors.affiliation: §Institut für Physikalische und Theoretische Chemie, Technische Universität Graz, Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Gatterer
authors.affiliation: †Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Marschner
authors.affiliation: ∥Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics (BUTE), Szent Gellért tér 4, 1111 Budapest, Hungary.
authors.forename: Tibor
authors.initials: T
authors.lastname: Szilvási
authors.affiliation: ‡Institut für Chemie, Universität Graz, Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Judith
authors.initials: J
authors.lastname: Baumgartner