Formation of Trichlorosilyl‐Substituted Carbon‐Centered Stable Radicals through the Use of π‐Accepting Carbenes

Abstract

A radical change: Cyclic alkyl(amino) carbenes formed zwitterionic adducts with SiCl4, which were further converted into carbon‐centered stable radicals by changing the donor‐acceptor C→Si coordinate bond into a CSi covalent bond through a KC8 reduction. As the carbon radical site was directly bonded to a SiCl3 unit, a radical center that is right next to an acceptor has been generated.

Electron-Induced Conversion of Silylones to Six-Membered Cyclic Silylenes

“…All the bond parameters suggest that 2a might be a singlet diradical (as shown in SI Figure S12) containing one radical each on Si1 and C24 atoms (Si1−C24 = 1.824(2) Å). Similar Si−C bond distances are observed in the monoradical (Cy-cAAC • )SiCl 3 (181.93 (8) Å) 13 and slightly smaller than those of SiCl 2 -bridged singlet diradical (Cy-cAAC • ) 2 SiCl 2 (1.400(2), 1.403(2) Å). 6b The stronger π-acceptor property 13−15 of cAAC over NHC (N-heterocyclic carbene) is the reason why cAAC transfers the electron density from the silicon atom of cAAC-SiCl 2 to the carbene carbon atom producing a singlet 1,2-diradical (SI Scheme S1a) which dimerizes to form a stable singlet 1,4-diradical (cAAC • ) 2 Si 2 Cl 4 (SI Scheme S1b).…”

Synthesis and Characterization of a Triphenyl‐Substituted Radical and an Unprecedented Formation of a Carbene‐Functionalized Quinodimethane

“…Thus, the cAAC is becoming more nucleophilic, but also more electrophilic compared with that of NHC 3–4. Consequently, a number of radical species of main‐group elements (PN + ,5a P 2 + ,5b RP + ,5c HB + ,5d CO + ,5e a ketene with biradical character,5f SiCl 2 ,6 Si,7 and SiCl 3 8) were stabilized by cAAC.…”

“…Recently, the bonding properties of cAAC with main‐group elements were investigated 2. 4, 5–8 Moreover, the C:→Si coordination bond in cAAC:→SiCl 4 was adjusted to an electron‐sharing CSi single bond in the monoradical (cAAC)SiCl 3 ( 1 ) utilizing the benign π‐accepting property of cAAC compared to that of NHC 8. The DFT calculations on 1 showed that the radical electron resides in the p z orbital of the carbene carbon atom and interacts with the p z orbital of the nitrogen atom and one chlorine atom as well.…”

A Stable Neutral Radical in the Coordination Sphere of Aluminum

“…In contrast, stable radical complexes with neutral aluminum centers have not been isolated whereas stable M II (boryl) 2 (M = Ga, In, Tl) radicals have recently been reported by the groups of Aldridge and Jones. [15] Herein, we describe aneutral aluminum radical complex with an AlCl 2 center coordinated by two cAACs.T he monomeric radical complex (Me 2 -cAAC) 2 AlCl 2 could be prepared at ambient temperature.F or ab etter understanding of this structure,wealso provide aquantum-chemical analysis of the bonding situation. To the best of our knowledge,the only example of acarbenestabilized complex with low-valent aluminum is the NHC adduct of dialane (Al 2 H 4 ), which was reported by Jones et al in 2010.…”