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Reactions of the amidinate-stabilized silicon(II) bis(trimethylsilyl)amide [LSiN(SiMe3)2], {L = PhC(N tBu)2, 1} with a stiochiometric amount of elemental sulfur, selenium and tellurium afforded the first stable silanechalcogenones comprising an acyclic amido substituent [L{N(SiMe3)2}Si=E] {E = S ( 2), Se ( 3) or Te ( 4)}. All compounds were characterized by X-ray crystallography and multinuclear NMR spectroscopy. The results illustrate that these compounds possess some silicon-chalcogen double bond character. [ABSTRACT FROM AUTHOR]

An isolable phenylborylene species supported by two oxazol-2-ylidene ligands was synthesized and structurally characterized. Computational studies revealed the presence of lone-pair electrons on the boron atom in this molecule; therefore, there are eight electrons around the three-coordinate boron center. The nucleophilic property was confirmed by the reactions with trifluoromethanesulfonic acid and [(thf)Cr(CO)5], which gave the corresponding conjugate acid and a chromium-borylene complex, respectively. [ABSTRACT FROM AUTHOR]

The reaction of the NHC-disilicon(0) complex [(IAr)Si=Si(IAr)] ( 1, IAr=:C{N(Ar)C(H)}2, Ar=2,6- iPr2C6H3) with two equiv of elemental Te in toluene at room temperature for three days afforded a mixture of the first dimeric NHC-silicon monotelluride [(IAr)Si=Te]2 ( 2) and its isomeric complex [(IAr)Si(μ-Te)Si(IAr)=Te] ( 3). When the same reaction was performed for ten days, only 3 was isolated from the reaction mixture. Compound 1 reacted with four equiv of elemental Te in toluene for four weeks, which proceeded through the formation of 2, 3 and the NHC-disilicon tritelluride complex [{(IAr)Si(=Te)}2Te] ( 5-Te), to form the dimeric NHC-silicon ditelluride [(IAr)Si(=Te)(μ-Te)]2 ( 4). The reactions are in line with theoretical mechanistic studies for the formation of 4. Compound 3 reacted with one equiv of elemental sulfur in toluene to form the first NHC-disilicon sulfur ditelluride complex [{(IAr)Si(=Te)}2S] ( 5-S). [ABSTRACT FROM AUTHOR]

Oxidative addition of the C−O bond in L2PhB: (L=oxazol-2-ylidene) to an AlI center induced ring expansion of an oxazol-2-ylidene ring, affording a unique organoboron species formally involving either an Al, N, O mixed heterocyclic carbene or anionic (amino)(boryl)carbene fragment. [ABSTRACT FROM AUTHOR]

An autoionization of germanium dichloride/dioxane complex with an imino-N-heterocyclic carbene ligand ( L) afforded a novel germyliumylidene ion, [( L)GeCl]+[GeCl3]−, which was fully characterized. Reduction of the germyliumylidene ion with potassium graphite produced a cyclic species [( L)Ge], which can be viewed as both a Ge0 species and a mesoionic germylene. X-ray diffraction analysis and computational studies revealed one of the lone pairs on the Ge atom is involved in the π system on the GeC2N2 five-membered ring. It was also confirmed that the nucleophilic behavior of [( L)Ge] as a two lone-pair donor. [ABSTRACT FROM AUTHOR]

An autoionization of germanium dichloride/dioxane complex with an imino-N-heterocyclic carbene ligand ( L) afforded a novel germyliumylidene ion, [( L)GeCl]+[GeCl3]−, which was fully characterized. Reduction of the germyliumylidene ion with potassium graphite produced a cyclic species [( L)Ge], which can be viewed as both a Ge0 species and a mesoionic germylene. X-ray diffraction analysis and computational studies revealed one of the lone pairs on the Ge atom is involved in the π system on the GeC2N2 five-membered ring. It was also confirmed that the nucleophilic behavior of [( L)Ge] as a two lone-pair donor. [ABSTRACT FROM AUTHOR]

The trapping of a silicon(I) radical with N-heterocyclic carbenes is described. The reaction of the cyclic (alkyl)(amino) carbene [cAACMe] (cAACMe=:C(CMe2)2(CH2)NAr, Ar=2,6- iPr2C6H3) with H2SiI2 in a 3:1 molar ratio in DME afforded a mixture of the separated ion pair [(cAACMe)2Si:.]+I− ( 1), which features a cationic cAAC-silicon(I) radical, and [cAACMe−H]+I−. In addition, the reaction of the NHC-iodosilicon(I) dimer [IAr(I)Si:]2 (IAr=:C{N(Ar)CH}2) with 4 equiv of IMe (:C{N(Me)CMe}2), which proceeded through the formation of a silicon(I) radical intermediate, afforded [(IMe)2SiH]+I− ( 2) comprising the first NHC-parent-silyliumylidene cation. Its further reaction with fluorobenzene afforded the CAr−H bond activation product [1-F-2-IMe-C6H4]+I− ( 3). The isolation of 2 and 3 confirmed the reaction mechanism for the formation of 1. Compounds 1- 3 were analyzed by EPR and NMR spectroscopy, DFT calculations, and X-ray crystallography. [ABSTRACT FROM AUTHOR]

The trapping of a silicon(I) radical with N-heterocyclic carbenes is described. The reaction of the cyclic (alkyl)(amino) carbene [cAACMe] (cAACMe=:C(CMe2)2(CH2)NAr, Ar=2,6- iPr2C6H3) with H2SiI2 in a 3:1 molar ratio in DME afforded a mixture of the separated ion pair [(cAACMe)2Si:.]+I− ( 1), which features a cationic cAAC-silicon(I) radical, and [cAACMe−H]+I−. In addition, the reaction of the NHC-iodosilicon(I) dimer [IAr(I)Si:]2 (IAr=:C{N(Ar)CH}2) with 4 equiv of IMe (:C{N(Me)CMe}2), which proceeded through the formation of a silicon(I) radical intermediate, afforded [(IMe)2SiH]+I− ( 2) comprising the first NHC-parent-silyliumylidene cation. Its further reaction with fluorobenzene afforded the CAr−H bond activation product [1-F-2-IMe-C6H4]+I− ( 3). The isolation of 2 and 3 confirmed the reaction mechanism for the formation of 1. Compounds 1- 3 were analyzed by EPR and NMR spectroscopy, DFT calculations, and X-ray crystallography. [ABSTRACT FROM AUTHOR]