Reversible Binding of Ethylene to Silylene–Phosphine Complexes at Room Temperature

Rodrı́guez, Ricardo; Gau, David; Kato, Tsuyoshi; Saffon‐Merceron, Nathalie; Cózar, Abel de; Cossío, Fernando P.; Baceiredo, Antoine

doi:10.1002/anie.201105097

Cited by 98 publications

(64 citation statements)

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“…4,7 The silylene 1 also reacts readily with excess norbornadiene (NBD) to generate a silirane 5 with a similar SiS2C core geometry to 3, in which one of the double bonds of NBD has reacted with the silicon atom in 1 (see Supporting Information). This reaction, however, is irreversible up to 162 °C, at which temperature 5 decomposes.…”

Section: )mentioning

confidence: 99%

“…3 to generate the 1,4-distannabicyclo[2.2.0]butanes, as exemplified in Scheme 1 (1), or the reversible binding of ethylene by the silylene-phosphine complex (also described as a phosphonium sila-ylide), as shown in Scheme 1 (2), to give the corresponding silirane product with a penta-coordinate silicon atom. 4 Scheme 1. Illustration of reversible reactions of main group compounds with ethylene near room temperature.…”

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“…These include disilynes, 12 digermynes, 3 frustrated Lewis-pair borane-phosphine molecules, 13 silylenes, 14 silylene precursors, 7k and digallenes, 15 but reversibility in ethylene binding, which is key for the development of possible catalysts, remains rare. 3,4 Further studies of the electronic factors that govern the reversibility of ethylene complexation by silylenes and their heavier group 14 element congeners are in hand. …”

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Reversible Complexation of Ethylene by a Silylene under Ambient Conditions

et al. 2014

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Reversible Complexation of Ethylene by a Silylene under Ambient Conditions

et al. 2014

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“…TheS iÀSi single bond lengths vary between 2.311(2) and 2.392(2) .C uriously,i nt he 29 Si NMR spectrum of 5 in C 6 D 6 solution at 25 8 8Conly one signal at d = 14.28 ppm is observed, while in the solid state CP-MAS 29 Si NMR revealed the expected three signals at d = 14.72, 8.39, and À88.75 ppm. Finally,wepondered the question whether the formation of 5 proceeds 1) as an intramolecular isomerization or 2) through the dissociation of styrene from the kinetic product 4.Afew reversible [1+ +2] cycloadditions involving silylenes and ethylene have indeed been reported, for example,t he reaction of ethylene with ap hosphonium silaylide [17] and with acyclic silylenes. 19, 9.28, and À84.22 ppm, which coalesce in ar ather undefined manner upon warming to room temperature.T hese findings suggest that the two signals at d = 9.28 and À84.22 ppm arise from an unknown dynamic process.D espite the high probability that the upfield signal at d = À84.22 ppm belongs to the SiTip 2 moiety on grounds of similarity with 2a,w ec onfirmed the assignment by calculating the NMR shifts at the M06-2X/ def2TZVPP level of theory.T he results (d 29 Si calcd = À79.04 (SiTip 2 ), 29.43 (SiCPh), 20.90 (SiCH 2 )ppm) are in qualitative agreement with the experiments.W et entatively explain the peculiar NMR behavior with hindered rotation at the two more congested silicon atoms.…”

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Disilenyl Silylene Reactivity of a Cyclotrisilene

et al. 2018

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The highly reactive silicon congeners of cyclopropene, cyclotrisilenes (c-Si R ), typically undergo either π-addition to the Si=Si double bond or σ-insertion into the Si-Si single bond. In contrast, treatment of c-Si Tip (Tip=2,4,6- Pr C H ) with styrene and benzil results in ring opening of the three-membered ring to formally yield the [1+2]- and [1+4] cycloaddition product of the isomeric disilenyl silylene to the C=C bond and the 1,2-diketone π system, respectively. At elevated temperature, styrene is released from the [1+2]-addition product leading to the thermodynamically favored housane species after [2+2] cycloaddition of styrene and c-Si Tip .

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“…This chelating ligand possesses both an important donor potential due to the electron rich substituents on P and significant steric bulk. Diaminophosphines have been successfully employed in the stabilization of reactive species [81][82][83][84][85]. Coordination of ligand 40 to [(THT)AuCl] yielded the corresponding gold(I) chloride complex 41 (Scheme.…”

Section: Influence Of the Substitution Pattern At P On The Oxidative mentioning

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Gold: Oxidative Addition to Au(I)

Joost

2015

Synthesis and Original Reactivity of Copper and Gold Complexes

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In this chapter, the results obtained during the course of this Ph.D. work concerning intermolecular σ-bond activation processes with gold(I) are exposed: (i) the oxidative addition of σ-SiSi bonds at monoligated cationic gold(I) complexes, (ii) the design of diphosphine gold(I) complexes suitable for oxidative addition reactions and (iii) application of the latter in σ-bond activation processes (strained carbocycles and simple aryl halides) will be discussed. Intermolecular SiSi Bond Activation at Au(I)As mentioned above, it was found that disilanes undergo oxidative addition to gold (I) in an intramolecular manner (see Sect. 3.3.3). In that work, the product was stabilized by chelate assistance of two (Scheme 3.13) or only one (Scheme 3.15) phosphine donor atoms pre-orientating the σ-SiSi bond and stabilizing the ensuing oxidative addition product. At the same time, chelate assistance raises the question of the role and importance of the anchoring sites used to promote disilane activation.We therefore started to investigate if similar transformations would also proceed intermolecularly. Besides elucidating the role of chelate assistance, the study of an intermolecular oxidative addition to gold(I) should pave the way for subsequent transformations (transmetallation, CH activation, reductive elimination) as encountered for example in 2-electron redox catalysis based on group-10 metals. Prominent illustrations are the palladium-catalyzed cross-coupling reactions of aryl halides and p-block element-based carbon-nucleophiles (e.g. arylboronic acids, arylstannanes, arylsilanes, etc.) for which oxidative addition of a carbon-halogen bond to a palladium complex is the entry point in the catalytic cycle, before transmetallation and reductive elimination yields CC-coupled products.Consequently our efforts concentrated on the identification of gold(I) complexes that are (i) able to undergo oxidative addition of disilanes and (ii) yield gold(III) complexes which are sufficiently stable to study their reactivity. We started to explore the reactions of simple monophosphine gold complexes with disilanes. Experimental ResultsAs a first control experiment, one equivalent of disilane (PhMe 2 Si) 2 was added to the phosphine gold complex (Ph 3 P)AuCl in toluene (Scheme 5.1).No reaction occurred over days at room temperature and progressive heating up to 100°C only led to decomposition of the gold precursor. Neutral (L)AuCl complexes are commonly activated with chloride abstractors, and thus we sought to generate a more electrophilic gold species using GaCl 3 . Upon addition of GaCl 3 (1 eq.), the 31 P NMR signal of (Ph 3 P)AuCl shifted from δ = 33 ppm to δ = 31 ppm. The resulting adduct is stable for hours at −80°C, but rapidly decomposes at higher temperatures. Upon addition of (PhMe 2 Si) 2 to a 1:1 mixture of (Ph 3 P)AuCl and GaCl 3 in CD 2 Cl 2 at −90°C (Scheme 5.2), the solution immediately turned to light yellow. Analysis of the reaction mixture by 31 P NMR spectroscopy at −80°C indicated the formation of a new species 24a...

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Reversible Binding of Ethylene to Silylene–Phosphine Complexes at Room Temperature

Cited by 98 publications

References 41 publications

Reversible Complexation of Ethylene by a Silylene under Ambient Conditions

Reversible Complexation of Ethylene by a Silylene under Ambient Conditions

Disilenyl Silylene Reactivity of a Cyclotrisilene

Gold: Oxidative Addition to Au(I)

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