1070876-63-9

Usage

Reaction

A stable silicon(0) compound with a Si=Si double bond.

Upstream product

• 1070876-61-7 C₂₇H₃₆Cl₄N₂Si 

Downstream Products

• 1309604-71-4 ((HCN(2,6-iPr₂C₆H₃))2C)Si(BH₃)(C₃H₂N₂(2,6-iPr₂C₆H₃)2)BH₃ 

Relevant academic research and scientific papers

Addition of Small Electrophiles to N-Heterocyclic-Carbene-Stabilized Disilicon(0): A Revisit of the Isolobal Concept in Low-Valent Silicon Chemistry

Protonation and alkylation of (Idipp)S=Si(Idipp) (1) afforded the mixed-valent disilicon(I)-borates [(Idipp)(R)SiII=Si0(Idipp)][B(ArF)4] (1R[B(ArF)4]; R = H, Me, Et; ArF = C6H3-3,5-(CF3)2; Idipp = C[N(C6H3-2,6-iPr2)CH]2) as red to orange colored, highly air-sensitive solids, which were characterized by single-crystal X-ray diffraction, IR spectroscopy and multinuclear NMR spectroscopy. Dynamic NMR studies in solution revealed a degenerate isomerization (topomerization) of the "σ-bonded" tautomers of 1H[B(ArF)4], which proceeds according to quantum chemical calculations via a NHC-stabilized (NHC = N-heterocyclic carbene) disilahydronium ion ("π-bonded" isomer) and is reminiscent of the degenerate rearrangement of carbenium ions formed upon protonation of olefins. The topomerization of 1H[B(ArF)4] provides the first example of a reversible 1,2-H migration along a Si=Si bond observed in a molecular system. In contrast, 1Me[B(ArF)4] adopts a "rigid" structure in solution due to the higher energy required for the interconversion of the "σ-bonded" isomer into a putative NHC-stabilized disilamethonium ion. Addition of alkali metal borates to 1 afforded the alkali metal disilicon(0) borates 1M[BAr4] (M = Li, Ar = C6F5; M = Na, Ar = ArF) as brown, air-sensitive solids. Single-crystal X-ray diffraction analyses and NMR spectroscopic studies of 1M[BAr4] suggest in concert with quantum chemical calculations that encapsulation of the alkali metal cations in the cavity of 1 predominantly occurs via electrostatic cation-π interactions with the Si=Si π-bond and the peripheral NHC aryl rings. Displacement of the [Si(NHC)] fragments by the isolobal fragments [PR] and [SiR]- interrelates the cations [(NHC)(R)Si=Si(NHC)]+ to a series of familiar, multiply bonded Si and P compounds as verified by analyses of their electronic structures.

One-Electron Oxidation of a Disilicon(0) Compound: An Experimental and Theoretical Study of [Si2]+ Trapped by N-Heterocyclic Carbenes

One-electron oxidation of the disilicon(0) compound Si2(Idipp)2 (1, Idipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) with [Fe(C5Me5)2][B(ArF)4] (ArF=C6H3-3,5-(CF3)2) affords selectively the green radical salt [Si2(Idipp)2][B(ArF)4] (1-[B(ArF)4). Oxidation of the centrosymmetric1 occurs reversibly at a low redox potential (E1/2=-1.250V vs. Fc+/Fc), and is accompanied by considerable structural changes as shown by single-crystal X-ray structural analysis of 1-B(ArF)4. These include a shortening of the S-Si bond, a widening of the Si-Si-CNHC angles, and a lowering of the symmetry, leading to a quite different conformation of the NHC substituents at the two inequivalent Si sites in 1+. Comparative quantum chemical calculations of 1 and 1+ indicate that electron ejection occurs from the symmetric (n+) combination of the Si lone pairs (HOMO). EPR studies of 1-B(ArF)4 in frozen solution verified the inequivalency of the two Si sites observed in the solid-state, and point in agreement with the theoretical results to an almost equal distribution of the spin density over the two Si atoms, leading to quite similar 29Si hyperfine coupling tensors in 1+. EPR studies of 1-B(ArF)4 in liquid solution unraveled a topomerization with a low activation barrier that interconverts the two Si sites in 1+. The radical salt [Si2(Idipp)2][B(ArF)4] was obtained upon one-electron oxidation of the disilicon(0) compound Si2(Idipp)2. The open-shell compound was characterized by experimental and quantum-chemical methods, providing a detailed insight into the unusual electronic structure and bonding situation of this σ-type radical.

Synthesis and Stabilization of Neutral Compounds with Homonuclear Bonds

The present invention is directed to the synthesis and stabilization of neutral molecules containing homonuclear single or multiple bonds, methods of preparation, and uses thereof.