Excellent yield of a variety of silicon-boron radicals and their reactivity

Nazish, Mohd; Ding, Yi; Legendre, Christina M.; Kumar, Arun; Graw, Nico; Schwederski, Brigitte; Herbst‐Irmer, Regine; Parvathy, Parameswaran; Parameswaran, Pattiyil; Kaim, Wolfgang; Roesky, Herbert W.

doi:10.1039/d2dt01318e

Cited by 7 publications

(2 citation statements)

References 63 publications

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“…29,38 Fascinated by the reactivity of bis-silylene we envision to explore the reactivity of new unsymmetrical bissilylene with highly reactive silylene. [39][40][41][42] Reaction of unsymmetrical bis-silylene with chlorosilylene (LSiCl) under reducing conditions in THF at -78 o C to room temperature resulted in the formation of a red-coloured solution. After two weeks reddish block-shaped crystals were obtained from Et 2 O solution at -30 °C which con rmed the formation of 4π-electron Si-containing four-membered ring (3).…”

Section: Methodsmentioning

confidence: 99%

Neutral 4π-electron tetrasilacyclobutadiene contains unusual features of a Möbius-type aromatic ring

Frenking,

Nazish,

Roesky

et al. 2024

Preprint

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We report the isolation and characterization of the novel 4π-electron tetrasilacyclobutadiene, an analogue of a 4π neutral cyclobutadiene that exhibits surprising features of a Möbius-type aromatic ring. Reduction of RSiCl3 (R = (iPr)2PC6H4) with KC8 in the presence of cycloalkyl amino-carbene (cAAC) led to the formation of corresponding silylene 1. Compound 1 shows further reactivity when treated with RSiCl3 under reducing conditions resulting in the formation of unsymmetrical bis-silylene 2, which was isolated as a dark red crystalline solid. Compound 3 was obtained when chlorosilylene was reduced with potassium graphite in the presence of 2. Although 3 is, according to Hückel’s rule an antiaromatic system it possesses significant aromatic character due to the unusual delocalization of the HOMO-1 and the loss of degeneracy of the higher-lying π MOs. The aromatic character of 3 is indicated by the structural stability of the compound by the very similar Si-Si bond lengths and by the NICS values. There is an unusual π conjugation between the 4 π electrons in the nearly square-planar Si4 ring where the delocalization of the HOMO-1 occurs at two opposite sides of the ring. The reversal of the π conjugation resembles the twisting of the π conjugation in Möbius aromatic systems and it contributes to the stability of the compound.

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Section: Methodsmentioning

confidence: 99%

Neutral 4π-electron tetrasilacyclobutadiene contains unusual features of a Möbius-type aromatic ring

Frenking,

Nazish,

Roesky

et al. 2024

Preprint

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show abstract

“…Such lack of isolable stiba‐ and bismasilenes provoked us to challenge the preparation of a doubly bonded heavy analogues R 2 Si=Ear (E=P, Sb, Bi), of the Schiff base derivatives. Surprisingly the reactivity of amidinate stabilized silylene towards antimony‐based compound remained almost unexplored [10b–h] . Which embarked us to synthesize phosphasilenes >Si=P− and its heavy homologue stibasilene >Si=Sb− using advantage of the above‐described unified synthetic approach, unfortunately could not obtained the bismasilenes.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Substituted Phosphasilenes and its Rare Homologue Stibasilene >Si=Sb−

Nazish,

Legendre,

Herbst‐Irmer

et al. 2023

Chemistry A European J

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Herein we report the reduction of R‐EX2 (E=P, Sb) with two equivalents of KC8 in the presence of silylene (LSiR; L=PhC(NtBu)2) to give Trip‐P=SiL(C6H4PPh2) (1), TerPh−P=(tBu)SiL (2) and TerPh−Sb=(tBu)SiL (3). The last (3) belongs to a new class of heavier analogues of Schiff bases (>C=N−), containing a formal >Si=Sb− double bond. The theoretical calculations suggest that lone pairs on the dicoordinated group‐15 centers are stabilized by hyperconjugative interactions resulting in pseudo‐Si−P/Si−Sb multiple bonds which are highly reactive as indicated by the high first and second proton affinities.

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Coordination and Stabilization of a Lithium Ion with a Silylene

Nazish

Legendre

Graw

et al. 2023

Chemistry A European J

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Herein, we report the stabilization of lithium‐ion as the source of lithium to use as a trans‐metalation reagent [{PhC(NtBu)2Si(tBu)Li}2I(tBuN)2CPh] (1). The reaction of 3 equivalents of the LSitBu (L=PhC(NtBu)2) and lithium iodide at low temperature leads to a silylene stabilized lithium‐ion with an additional coordination of amidinate ligand. Compound 1 shows two four membered and one six membered ring as confirmed by QTAIM calculations. Whereas the reaction of the LSiCl with 1.5 equivalents of carbodiimide (CyN)2C at room temperature affords compound [PhC(NtBu)2Si(Cl)(NCy)2NCy] (2) with the CN2SiN2C skeleton containing silicon as a central atom. Both the compounds were fully characterized by NMR, mass spectrometry, X‐ray crystallographic analysis, and quantum mechanical calculations.

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Excellent yield of a variety of silicon-boron radicals and their reactivity

Abstract: Herein we report stable silicon-boron radicals of composition LSi(NMe2)-B(Br)Tip (1), LSi(NMe2)-B(I)Tip (2) LSi(tBu)-B(I)Tip (3) [L=PhC(NtBu)2]. They were prepared in high yield using a one-pot reaction of LSiR, X2BTip, and KC8...

Cited by 7 publications

References 63 publications

Neutral 4π-electron tetrasilacyclobutadiene contains unusual features of a Möbius-type aromatic ring

Neutral 4π-electron tetrasilacyclobutadiene contains unusual features of a Möbius-type aromatic ring

Synthesis and Characterization of Substituted Phosphasilenes and its Rare Homologue Stibasilene >Si=Sb−

Coordination and Stabilization of a Lithium Ion with a Silylene

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