Air-Stable Tetrakis(2,4,6-triisopropylphenyl)disilene. Direct Synthesis of Disilene from Dihalomonosilane

Abstract

The most air-stable disilene, tetrakis(2,4,6-triisopropylphenyl) disilene was obtained by the direct treatment of dichloromonosilane, bis(2,4,6-triisopropylphenyl)dichlorosilane, with lithium naphthalenide. The Si=Si bond, the distance being 2.144 Å via X-ray structure analysis, was found to be sterically covered with the four bulky substituents.

The Versatile Chemistry of Disilenides: Disila Analogues of Vinyl Anions as Synthons in Low-valent Silicon Chemistry

“…The obvious similarity between the reaction conditions of the originally reported synthesis of 11 by Watanabe 26 and its assumed reduction to 10 as reported by Weidenbruch served as 27 Disilenide 10 exhibited a rather surprising thermal stability melting at 121°C with only little decomposition.…”

“…The weak SiLi bond in 10 can be explained by the coordination with two dme molecules leading to an overall coordination number of 5 at the lithium cation (distorted square pyramidal). The most pertinent structural features, however, are an SiSi bond length, which is with 2.192(1) ¡ significantly longer than the corresponding bond in neutral 11, 26 as well as a relatively small SiSiC angle (107.6(1)°) at the negatively charged silicon atom, reflecting the high s character of the SiLi bond.…”

“…9a In order to generate 10, Weidenbruch and coworkers treated Watanabe's disilene 11 26 with elemental lithium in 1,2-dimethoxyethane (dme) in the expectation that one of the four Tip substituents would be cleaved off reductively in analogy to what had been reported by Masamune et al for Tip 2 Ge=GeTip 2 . 28 The isolation of the final product of this reaction sequence, tetrasilabutadiene 6a, lent the proposed intermediacy of 10 significant support.…”

The Synthesis and Properties of Bimetallic d-^|^pi; Electron Systems Containing Metallocenyl Substituents of Fe or Ru, and ^|^pi;-Electron Spacers of Heavier Main Group Elements from Group 14 or 15

“…Similarly to previously reported disilenes, a trans bent conformation was observed for 1, with the crystallographic center of symmetry at the center of the Si Si bond. In stark contrast to Tip 2 Si SiTip 2 , 14 which was reported to be almost The UV/vis spectrum of 1 in hexane showed two characteristic absorption maxima at 332 (ε 5,900) and 427 nm (24,000). Previous reports on tetraaryldisilenes described absorption maxima around 400 460 nm, which were assigned to π π electron transitions of the Si Si chromophore.…”

“…13 Moreover, TipSiCl 3 should be an appropriate synthetic precursor, as it is stable enough to be handled under ambient conditions. This assumption seems feasible, considering that the corresponding homoleptically substituted disilene Tip 2 Si SiTip 2 , 14 with a distinct Si Si double bond, exhibits suf cient stability. The synthetic route for the generation of 1,2 bis(Fc)disilene 1 is outlined in Scheme 3.…”