Homoleptic Tris(α,ω-alkanediyl)yttriates of the Type [{Li(dme)}₃{Y(CH₂-X-CH₂)₃}] (X = C₂H₄, C₃H₆, Si(CH₃)₂)

Abstract

The metathesis reaction of anhydrous yttrium(III) chloride with ethereal solutions of 1,4-dilithiobutane, 1,5-dilithiopentane as well as bis(lithiomethyl)dimethylsilane in the molar ratio of 1:3 yields the homoleptic yttriates [{Li(dme)} 3 {Y-(C 4 H 8 ) 3 }] (2), [{Li(dme)} 3 {Y(C 5 H 10 ) 3 }] (3), and [{Li(dme)} 3 (Y{CH 2 Si(CH 3 ) 2 CH 2 } 3 )] (4) after addition of 1,2-dimethoxyethane (DME). The molecular structures of 2 and 3 show hexa-coordinate yttrium atoms in distorted octahedral environments of three bidentate chelating α,ω-alkanediyl ligands. Three Li(dme) units occupy bridging positions between two α-CH 2 fragments of different ligands. These complexes decompose at 0 °C in THF-d 8 solution leading to the formation of methyl vinyl ether as well as n-butane and npentane, respectively. The 13 C{ 1 H} NMR experiment of 2 at −40 °C shows a doublet for the α-CH 2 fragment with a 1 J C,Y coupling constant of 21.6 Hz. For the thermally more stable complex 4 (NMR measurement at r.t.), a 1 J C,Y coupling constant of 16.9 Hz was observed. Bis(lithiomethyl)dimethylsilane crystallizes as the cage compound [(Et 2 O) 4 {(LiCH 2 ) 2 Si(CH 3 ) 2 } 3 (LiCl)] 2 (1) with a shell-like structure around the central chloride ions. YCl 3 reacts with an excess of phenyllithium in diethyl ether to a product mixture. Lithium chloride can be removed with tetrahydropyran (THP) as [(thp) 2 LiCl] 2 (5). After the addition of THF to the residue, [Ph 3 Y(thf) 3 ] (6, 1 J C,Y = 48.7 Hz) could be identified in the solution. The applicability of complexes 2, 3, and 4 as initiators for styrene polymerization is studied in THF solution at −70 °C.

Syntheses and Molecular Structures of [(thf)4Li] [{(thf)Li}M(C4H8)3] (M = Zr, Hf) and Their Solution Behavior

“…The quotient k D / k H (kinetic isotope effect of 2 D/ 1 H) of this reaction has a value of 7. A similarly stabilizing solvent effect of [D 8 ]THF has been observed earlier for solutions of related [{(thf) 2 Li} 3 Y(C 4 H 8 ) 3 ] . Initially the butane‐1,4‐diide ions form n‐butyl groups.…”

“…Crystallographically authenticated homoleptic metalates have been reported for chromium(II), nickel(II), platinum(II), magnesium(II), and zinc(II) . In order to study the dependency of the molecular structures on the oxidation state of the metal we also prepared and investigated the yttrium(III) congener . Homoleptic metalates with central metal(IV) atoms are missing as of yet.…”

Magnesiacycloalkanes with Different Ring Sizes

“…The chemical shift of the magnesium-bound carbon atoms shows a value of δ = 21.4. This shift lies between the values of δ = 19.7 and 23.3, which were assigned to the mono- and dinuclear species in solution of related [({thf} 2 Mg­{μ-C­(CH 3 ) 2 ­(CH 2 ) 2 C­(CH 3 ) 2 }) 2 ] . Therefore, it was impossible to clarify the aggregation degree despite the fact that a uniform compound exists in solution.…”

“…We could show that an analogous dinuclear magnesium compound is also realized if the tertiary 2,5-dimethyl-2,5-dichlorohexane is used as a substrate in the Grignard reaction . However, in [({thf} 2 Mg­{μ-C­(CH 3 ) 2 ­(CH 2 ) 2 C­(CH 3 ) 2 }) 2 ] the C–Mg–C bond angle of 122.86(7)° between the magnesium-bound alkyl chains is significantly smaller .…”

Dilithium and Magnesium Alkanediides and 1‐Oxaalkanediides

“…The research group of Fröhlich prepared such complexes of the late transition metals nickel, palladium, platinum, and zinc . Recently, derivatives of the electropositive metals magnesium and yttrium were prepared and structurally authenticated.…”