Group 4 Metal and Lanthanide Complexes in the Oxidation State +3 with Tris(trimethylsilyl)silyl Ligands

Abstract

A number of paramagnetic silylated d1 group 4 metallates were prepared by reaction of potassium tris(trimethylsilyl)silanide with group 4 metallates of the type K[Cp2MCl2] (M = Ti, Zr, Hf). The outcomes of the reactions differ for all three metals. While for the hafnium case the expected complex [Cp2Hf{Si(SiMe3)3}2]− was obtained, the analogous titanium reaction led to a product with two Si(H)(SiMe3)2 ligands. The reaction with zirconium caused the formation of a dinuclear fulvalene bridged complex. The desired [Cp2Zr{Si(SiMe3)3}2]− could be obtained by reduction of Cp2Zr{Si(SiMe3)3}2 with potassium. In related reactions of potassium tris(trimethylsilyl)silanide with some lanthanidocenes Cp3Ln (Ln = Ce, Sm, Gd, Ho, Tm) complexes of the type [Cp3Ln Si(SiMe3)3]− with either [18-crown-6·K]+ or the complex ion [18-crown-6·K·Cp·K·18-crown-6] as counterions were obtained. Due to d1 or fn electron configuration, unambiguous characterization of all obtained complexes could only be achieved by single crystal XRD diffraction analysis.

f-Element silicon and heavy tetrel chemistry

“…53 In a later report, Baumgartner and co-workers reported a samarium analogue 30-Sm to add to the 30-Ln series. 67 In Fig. 10).…”

Rare-Earth–Silyl ate-Complexes Opening a Door to Selective Manipulations

“…8 − 12 Some years ago our group has entered the field and we have contributed a few examples of lanthanide complexes with mono- or bidentate oligosilanyl ligands. 13 − 17 …”

“…This was already observed by Schumann and co-workers in their reactions of Na[Cp 2 LnCl 2 ] (Ln = Dy, Ho, Er, Tm, and Lu) with 2 equiv of Me 3 SiLi to Li[Cp 2 Ln(SiMe 3 ) 2 ] 5 − 7 and later confirmed by us in reactions of Cp 3 Ln with (Me 3 Si) 3 SiK, which led to K[Cp 3 LnSi(SiMe 3 ) 3 ] ate-complexes for the elements Ce, Sm, Gd, Ho, and Tm. 17 Reacting Cp 3 Ln with K(Me 3 Si) 2 Si(SiMe 2 ) 2 Si(SiMe 3 ) 2 K 19 , 20 led to the cyclic disilylated products K[Cp 2 Ln{Si(SiMe 3 ) 2 SiMe 2 } 2 ] via elimination of CpK for Ln = Sm, Gd, Tb, Ho, and Tm. 13 , 17 The reaction of the oligosilanylene diide with Cp 3 Ce took a different course to the acyclic complex K 2 [Cp 3 Ce(Me 3 Si) 2 Si(SiMe 2 ) 2 Si(SiMe 3 ) 2 CeCp 3 ].…”

“… 17 Reacting Cp 3 Ln with K(Me 3 Si) 2 Si(SiMe 2 ) 2 Si(SiMe 3 ) 2 K 19 , 20 led to the cyclic disilylated products K[Cp 2 Ln{Si(SiMe 3 ) 2 SiMe 2 } 2 ] via elimination of CpK for Ln = Sm, Gd, Tb, Ho, and Tm. 13 , 17 The reaction of the oligosilanylene diide with Cp 3 Ce took a different course to the acyclic complex K 2 [Cp 3 Ce(Me 3 Si) 2 Si(SiMe 2 ) 2 Si(SiMe 3 ) 2 CeCp 3 ]. 13 …”

Polarised covalent thorium(iv)– and uranium(iv)–silicon bonds

“…The central Si atoms of the hypersilanide ligands in 2-An deviate significantly from tetrahedral geometries, with mean Si-Si-An bond angles of 116.48(6)1 (2-Th) and 116.97(7)1 (2-U) indicating significant steric repulsion between the trimethylsilyl substituents; a similar effect was reported for [U{N( t Bu)(C 6 H 3 Me 2 -3,5)} 3 {Si(SiMe 3 ) 3 }] (mean Si-Si-An: 115.43(8)1). 14 For both 2-Th and 2-U, the 1 H NMR spectra exhibit two Cp 0 -H resonances for the aand b-CH positions (2-Th: d H = 6.26 ppm, 6.72 ppm; 2-U: d H = 0.25 ppm, 0.37 ppm), and two resonances of equal intensity for the two chemically inequivalent trimethylsilyl environments (2- 30 we added one equivalent of Si(SiMe 3 ) 4 to a sample of 2-U ( Fig. S10 and S11, ESI †) to show that Si(SiMe 3 ) 4 resonates at different chemical shifts to that of 2-U.…”