18909-18-7Relevant articles and documents
A C2-Linked Bis-silene Formed without Using Metals and the Transformation into the Bis-silyl and Bis-silylium C4-Cumulenes
Chen, Yilin,Li, Jiancheng,Jiang, Wenjun,Zhao, Jinbo,Zhu, Hongping,Muhammed, Shahila,Parameswaran, Pattiyil,Roesky, Herbert W.
, p. 4282 - 4286 (2020)
Reaction of silylene L(Cl)Si: (1; L = PhC(NtBu)2) with 1,3-diyne Me3SiCCCCSiMe3produced bis-silene L(Cl)Si=C(SiMe3)CC(SiMe3)C=Si(Cl)L (2). This shows a route by oxidative coupling reaction to silenes. Reaction of 2 with AgOSO2CF3resulted in [L(Cl)(F3CO2SO)Si](Me3Si)C=C=C=C(SiMe3)[Si(OSO2CF3)(Cl)L] (3) and a silver mirror. From the reaction of 2 and B(C6F5)3were isolated compounds {[L(Cl)Si](Me3Si)C=C=C=C(SiMe3)[Si(Cl)L]}2+·2[ClB(C6F5)3]-(4) and {LSi[μ2-C2(SiMe3)(CCSiMe3)]}2(5). When 2 was treated with [Ph3C]+[B(C6F5)4]-, compounds [L2(Cl)Si]+[B(C6F5)4]-(6) and Ph2C=-cyclo-C(CH=CH)2CHCPh3(7) were formed. These reactions exhibit reduction of the polar Si=C bond to create unusual species of neutral and dicationic C4-cumulenes. The formation, bonding, and reactivity of compound 2 is explored by the computational quantum mechanical calculations.
A Base-Free Terminal Actinide Phosphinidene Metallocene: Synthesis, Structure, Reactivity, and Computational Studies
Zhang, Congcong,Hou, Guohua,Zi, Guofu,Ding, Wanjian,Walter, Marc D.
, p. 14511 - 14525 (2018)
The synthesis, structure, and reactivity of a base-free terminal actinide phosphinidene metallocene have been comprehensively studied. The salt metathesis reaction of the thorium methyl iodide complex Cp?2Th(I)Me (2; Cp? = η5-1,2,4-(Me3C)3C5H2) with Mes*PHK (Mes* = 2,4,6-(Me3C)3C6H2) in THF furnishes the first stable base-free terminal phosphinidene actinide metallocene, Cp?2Th═PMes* (3). Density functional theory (DFT) shows that the bonds between the Cp?2Th2+and [PMes*]2-fragments are more covalent than those in the related thorium imido complex. While the phosphinidene complex3shows no reactivity toward alkynes, it reacts with a variety of heterounsaturated molecules such as CS2, isothiocyanate, nitriles, isonitriles, and organic azides, forming carbodithioates, imido complexes, metallaaziridines, and azido compounds. These experimental observations are complemented by DFT computations.
A Phosphine-Coordinated Boron-Centered Gomberg-Type Radical
Rosenthal, Amos J.,Devillard, Marc,Miqueu, Karinne,Bouhadir, Ghenwa,Bourissou, Didier
, p. 9198 - 9202 (2015)
The P-coordinated boryl radical [Ph2P(naphthyl)BMes]. (Mes=mesityl) was prepared by (electro)chemical reduction of the corresponding borenium salt or bromoborane. Electron paramagnetic resonance (EPR) analysis in solution and DFT cal
Trivalent Rare-Earth-Metal Bis(trimethylsilyl)amide Halide Complexes by Targeted Oxidations
Bienfait, André M.,Wolf, Benjamin M.,T?rnroos, Karl W.,Anwander, Reiner
, p. 5204 - 5212 (2018)
In contrast to previously applied salt metathesis protocols the targeted rare-earth-metal compounds Ln[N(SiMe3)2]2(halogenido) were accessed by oxidation of Ln(II) silylamide precursors. Treatment of Sm[N(SiMe3)3]2(thf)2 with 0.5 equiv of C2Cl6 or 0.25 equiv of TeBr4 in thf and crystallization thereof gave [Sm{N(SiMe3)2}2(μ-X)(thf)]2 (X = Cl, Br). A similar reaction/crystallization procedure performed with 0.5 equiv of 1,2-diiodoethane gave monomeric Sm[N(SiMe3)2]2I(thf)2. Switching to Yb[N(SiMe3)2]2(thf)2, the aforementioned oxidants generated monomeric five-coordinate complexes Yb[N(SiMe3)2]2X(thf)2 (X = Cl, Br, I). The reaction of Eu[N(SiMe3)2]2(thf)2 with 0.5 equiv of C2Cl6 in thf yielded the separated ion pair [Eu{N(SiMe3)2}3Cl][(thf)5Eu(μ-Cl)2Eu(thf)5]. Performing the chlorination in n-hexane led to oxidation followed by rapid disproportionation into EuCl3(thf)x and Eu[N(SiMe3)2]3. The bromination reaction did not afford crystalline material, while the iodination gave crystals of divalent EuI2(thf)5. Use of trityl chloride (Ph3CCl) as the oxidant in thf accomplished the Eu(III) species [Eu{N(SiMe3)2}2(μ-Cl)(thf)]2. In situ oxidation of putative [Tm{N(SiMe3)2}2(thf)x] using 0.5 equiv of C2Cl6 in thf followed by crystallization from n-hexane led to the formation of a mixture of [Tm{N(SiMe3)2}2(μ-Cl)(thf)]2 and Tm[N(SiMe3)2]3. Switching the oxidant to 0.5 equiv of 1,2-diiodoethane and crystallizing from thf repeatedly afforded the bis-halogenated complex Tm[N(SiMe3)2]I2(thf)3.
Rapid Iron(III)?Fluoride-Mediated Hydrogen Atom Transfer
Doyle, Lorna M.,Gericke, Robert,McDonald, Aidan R.,Panda, Chakadola
supporting information, p. 26281 - 26286 (2021/11/12)
We anticipate high-valent metal–fluoride species will be highly effective hydrogen atom transfer (HAT) oxidants because of the magnitude of the H?F bond (in the product) that drives HAT oxidation. We prepared a dimeric FeIII(F)?F?FeIII(F) complex (1) by reacting [FeII(NCCH3)2(TPA)](ClO4)2 (TPA=tris(2-pyridylmethyl)amine) with difluoro(phenyl)-λ3-iodane (difluoroiodobenzene). 1 was a sluggish oxidant, however, it was readily activated by reaction with Lewis or Br?nsted acids to yield a monomeric [FeIII(TPA)(F)(X)]+ complex (2) where X=F/OTf. 1 and 2 were characterized using NMR, EPR, UV/Vis, and FT-IR spectroscopies and mass spectrometry. 2 was a remarkably reactive FeIII reagent for oxidative C?H activation, demonstrating reaction rates for hydrocarbon HAT comparable to the most reactive FeIII and FeIV oxidants.
Three-coordinate copper(II) alkynyl complex in C-C bond formation: The sesquicentennial of the glaser coupling
Warren, Timothy H.,Bakhoda, Abolghasem,Okoromoba, Otome E.,Greene, Christine,Boroujeni, Mahdi Raghibi,Bertke, Jeffery A.
supporting information, p. 18483 - 18490 (2020/11/27)
Copper(II) alkynyl species are proposed as key intermediates in numerous Cu-catalyzed C-C coupling reactions. Supported by a β-diketiminate ligand, the three-coordinate copper(II) alkynyl [CuII]-C≡CAr (Ar = 2,6-Cl2C6H3) forms upon reaction of the alkyne H-C≡CAr with the copper(II) tertbutoxide complex [CuII]-OtBu. In solution, this [CuII]-C≡CAr species cleanly transforms to the Glaser coupling product ArC≡C-C≡CAr and [CuI](solvent). Addition of nucleophiles R′C≡C-Li (R′ = aryl, silyl) and Ph-Li to [CuII]-C≡CAr affords the corresponding Csp-Csp and Csp-Csp2 coupled products RC≡C-C≡CAr and Ph-C≡CAr with concomitant generation of [CuI](solvent) and {[CuI]-C≡CAr}-, respectively. Supported by density functional theory (DFT) calculations, redox disproportionation forms [CuIII](C≡CAr)(R) species that reductively eliminate R-C≡CAr products. [CuII]-C≡CAr also captures the trityl radical Ph3C· to give Ph3C-C≡CAr. Radical capture represents the key Csp-Csp3 bond-forming step in the copper-catalyzed C-H functionalization of benzylic substrates R-H with alkynes H-C≡CR′ (R′ = (hetero)aryl, silyl) that provide Csp-Csp3 coupled products R-C≡CR via radical relay with tBuOOtBu as oxidant.
