Crystal structure of the [(THF)Cs(μ-η⁵:η⁵-Cp′)₃Yb] _n oligomer

Abstract

<jats:p>The green compound poly[(tetrahydrofuran)tris[μ-η<jats:sup>5</jats:sup>:η<jats:sup>5</jats:sup>-1-(trimethylsilyl)cyclopentadienyl]caesium(I)ytterbium(II)], [CsYb(C<jats:sub>8</jats:sub>H<jats:sub>13</jats:sub>Si)<jats:sub>3</jats:sub>(C<jats:sub>4</jats:sub>H<jats:sub>8</jats:sub>O)]<jats:sub> <jats:italic>n</jats:italic> </jats:sub> or [(THF)Cs(μ-η<jats:sup>5</jats:sup>:η<jats:sup>5</jats:sup>-Cp′)<jats:sub>3</jats:sub>Yb<jats:sup>II</jats:sup>]<jats:sub> <jats:italic>n</jats:italic> </jats:sub> was synthesized by reduction of a red THF solution of (C<jats:sub>5</jats:sub>H<jats:sub>4</jats:sub>SiMe<jats:sub>3</jats:sub>)<jats:sub>3</jats:sub>Yb<jats:sup>III</jats:sup> with excess Cs metal and identified by X-ray diffraction. The compound crystallizes as a two-dimensional array of hexagons with alternating Cs<jats:sup>I</jats:sup> and Yb<jats:sup>II</jats:sup> ions at the vertices and cyclopentadienyl groups bridging each edge. This, based off the six-electron cyclopentadienyl rings occupying three coordination positions, gives a formally nine-coordinate tris(cyclopentadienyl) coordination environment to Yb and the Cs is ten-coordinate due to the three cyclopentadienyl rings and a coordinated molecule of THF. The complex comprises layers of Cs<jats:sub>3</jats:sub>Yb<jats:sub>3</jats:sub> hexagons with THF ligands and Me<jats:sub>3</jats:sub>Si groups in between the layers. The Yb—C metrical parameters are consistent with a 4<jats:italic>f</jats:italic> <jats:sup>14</jats:sup> Yb<jats:sup>II</jats:sup> electron configuration.</jats:p>

van der Waals Heterostructures Based on Nanolayered Paramagnetic Tm(II) Compounds and Boron Nitride for Investigating Spin Frustration

“…Furthermore, the root-mean-square deviation (RMSD, ω hex ) of the six metal ions from the mean plane of their positions is ω hex = 0.669 Å, versus ω hex = 0 for a completely planar structure. These data are similar to those for the Yb­(II) analogue 1 : ω hex = 0.671 and dihedral angle 20.26° . This observed consistency between 1 and 2 demonstrates that the corrugated nature of the individual layers is not impacted by changing the M­(II) center from Yb­(II) to Tm­(II).…”

“…These data are similar to those for the Yb(II) analogue 1: ω hex = 0.671 and dihedral angle 20.26°. 24 This observed consistency between 1 and 2 demonstrates that the corrugated nature of the individual layers is not impacted by changing the M(II) center from Yb(II) to Tm(II).…”

“…Recently, an organometallic rare-earth compound, [(THF)­Cs­(μ-η 5 :η 5 -Cp′) 3 Yb II ] n ( 1 ; Cp′ = C 5 H 4 SiMe 3 ), was synthesized and found to have a layered structure (see Figure ) that could potentially be exfoliated to form thin films . Compound 1 is one of several recent structures that crystallize with layers of hexagonal networks comprised of three M­(II) ions (M = Ba, Yb, and U) and three Cs­(I) ions connected by bridging Cp′ ligands. , The trimethylsilyl groups of the Cp′ ligand and the methylene groups of the bound THF molecules extend outward perpendicular to the layer plane but do not form covalent bonds with other layers.…”