Cascade Activation of SiH, CH, and SiC Bonds at a Rhodium β‐Diiminate Complex

Zhu, Di; Kozera, Daniel J.; Enns, Kelly D.; Budzelaar, Peter H. M.

doi:10.1002/ange.201206751

Cited by 5 publications

(4 citation statements)

References 34 publications

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“…230 Scheme 5 shows the unusual changes in the products that were produced when[( i Pr 3 P) 2 Ni] 2 (N 2 ) was reacted with related primary, secondary, and tertiary silanes. [Note: a structurally related Rh complex (5-106 107 ) but with a nitrogen bidentate has also been reported. ]…”

Section: Reactions Of Silanes Initiated By Loss Of a Neutral Ligandmentioning

confidence: 99%

“…The reactions of other silanes with 2,6-Me 2 C 6 H 3 were also studied: HSi( n C 8 H 17 ) 3 (rearrangement), HSi( n C 8 H 17 )Me 2 , and HSi(cy-C 6 H 11 )Me 2 (both with rearrangement to two isomers, HSiPhMe 2 (complex decomposes). 107 69 L = β-diimidate (see structure for 5-106). 107 70 When 20 equiv of HSi(OEt) 3 was added to IrCl(CO)(PPH 3 ) 2 , IrCl(H) 2 (CO)(PPh 3 ) 2 formed in 82% yield (X-ray) plus a mixture of Si(OEt) 4 , (EtO) 2 SiOSi(OEt) 3 + (EtO) 2 HSiOSi(OEt) 3 .…”

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confidence: 99%

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Reactions of Hydrosilanes with Transition Metal Complexes

2016

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This third review in a series involving reactions of hydrosilanes and transition metal complexes and characterization of the products covers the period 2009 thru 2013. After a brief discussion of other synthetic methods used for the formation of Si-TM complexes, Section 3 provides an extended discussion of the types of ligands and metal complexes used as reactants with hydrosilanes. The increase in use of pincer ligands in forming stable, isolable complexes is featured. Three tables list the complexes reported for primary, secondary, and tertiary silanes. Many reactions leading to SiTM complexes are initiated by loss of a ligand prior to oxidative addition of the hydrosilane or by a metathesis reaction. Structural data are tabulated for the isolated complexes and provide the Si-TM bond ranges for the elements in the "d" block. A major section on nonclassical (σ or agostic) complexes includes two general groupings with Si-H···TM and M-H···Si interactions. A section on solution processes identified by NMR spectroscopy is dominated by hydride exchange examples. A section on bonding outlines a unifying bonding description that has been proposed as well as calculations reported for Si-TM complexes, both real and hypothetical examples.

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Section: Reactions Of Silanes Initiated By Loss Of a Neutral Ligandmentioning

confidence: 99%

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confidence: 99%

Reactions of Hydrosilanes with Transition Metal Complexes

2016

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“…The formation of these silyl-donor-functionalized NHC complexes can be viewed as the insertion of the silylene moieties into the CoÀC(benzyl) bond of 1, [17] but the genuine route is probably quite complicated. In an effort to probe the mechanism, we monitored the reaction of 1 with PhSiH 3 (1 equiv) in C 6 D 6 by 1 H NMR spectroscopy in a sealed NMR tube.…”

Section: Zhenbo Mo Yang Liu and Liang Deng*mentioning

confidence: 99%

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

2013

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Silyl ligands stand out as particularly versatile ligands owing to their exceptionally strong s-donating ability and trans effect. [1] These properties should make silyl-containing ligands capable of generating coordinatively unsaturated metal species, directing the coordination and dissociation of other ligands, and therefore conferring enhanced reactivity or accelerated catalytic turnover to their complexes. [2] N-Heterocyclic carbenes (NHCs) are another type of strongly s-donating ligand with a strong trans effect and have joined the cyclopentadienyl anions and phosphine ligands as particularly useful widely applied ligands. [3] Accompanying the emergence of versatile monodentate NHCs, [4] numerous functionalized NHC ligands featuring tethered substitutents or binding sites, such as borate, alkoxide, enolate, amine, amide, imine, heterocycle, thioether, and phosphine groups, have been developed and applied in transition-metal chemistry. [5,6] In contrast, functionalized NHC ligands featuring silyl donors have remained elusive, although some NHCs with silyl substitutents on the imidazole ring are known (Scheme 1). [7] The absence of this type of potentially useful ligand might result from the inherent challenge of combining a nucleophilic carbene with a Lewis acidic silane moiety in the same ligand scaffold, as there have been reports of silanes reacting with NHCs to afford Lewis acid-base adducts, [8] Si À H insertion products, [9] or even ring expansion of the NHC (Scheme 1). [10] With this knowledge in mind, we envisioned that instead of the direct synthesis of a silyl-donor-functionalized NHC ligand, a postsilylation method involving the reaction of hydrosilanes with a cyclometalated transition-metal-NHC complex might be a more feasible route. This idea was inspired by our previous finding that the cyclometalated NHC complex [Co(IMes') 2 ] (1) can react with CO, isocyanides, and diazo compounds to furnish novel donor-group-functionalized NHC complexes. [11] Herein, we report the preparation of the first silyl-donor-functionalized NHC complexes by a sequential cobalt-mediated C À H activation and silylation protocal, their reactivity toward H 2 and BH 3 ·thf, and more interestingly, their remarkable catalytic performance in the catalytic hydrosilylation of 1-octene with PhSiH 3 . In this transformation, the very fast initial rate and the high turnover number and selectivity of these catalysts were superior to those observed for [Co 2 (CO) 8 ] and [(IPr 2 Me 2 ) 2 CoPh 2 ] (IPr 2 Me 2 : 2,5-diisopropyl-3,4-dimethylimidazol-1-ylidene).Our previous study showed that the reduction of [(IMes) 2 CoCl], prepared from [(Ph 3 P) 3 CoCl] and IMes (IMes: 1,3-dimesitylimidazol-2-ylide), with sodium amalgam results in the formation of the cyclometalated cobalt(II)-NHC complex [Co(IMes') 2 ] (1; Scheme 2). [11] Upon further investigation, we found that 1 can be prepared more conveniently by the one-pot reaction of CoCl 2 with IMes (2 equiv) and sodium amalgam (2 equiv; Scheme 2). The addition of PhSiH 3 (1 equiv) to a su...

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“…The formation of these silyl‐donor‐functionalized NHC complexes can be viewed as the insertion of the silylene moieties into the CoC(benzyl) bond of 1 ,17 but the genuine route is probably quite complicated. In an effort to probe the mechanism, we monitored the reaction of 1 with PhSiH 3 (1 equiv) in C 6 D 6 by 1 H NMR spectroscopy in a sealed NMR tube.…”

Section: Methodsmentioning

confidence: 99%

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

Liu

Deng

2013

Angewandte Chemie

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Neuer Schwung für den Katalysator: Eine Reaktionssequenz aus Cobalt‐vermittelter C‐H‐Aktivierung und Silylierung wurde entwickelt und für die Herstellung von neuartigen Silyldonor‐funktionalisierten NHC‐Komplexen verwendet (siehe Schema; Mes=Mesityl; R=H, Me, Ph). Die erhaltenen Cobalt‐Komplexe zeigen hohe Aktivität und Selektivität in der katalytischen Hydrosilylierung von Olefinen.

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Cascade Activation of SiH, CH, and SiC Bonds at a Rhodium β‐Diiminate Complex

Cited by 5 publications

References 34 publications

Reactions of Hydrosilanes with Transition Metal Complexes

Reactions of Hydrosilanes with Transition Metal Complexes

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

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