An NHC–Silyl–NHC Pincer Ligand for the Oxidative Addition of C−H, N−H, and O−H Bonds to Cobalt(I) Complexes

Sun, Jian; Luo, Lun; Luo, Yi; Deng, Liang

doi:10.1002/anie.201611162

Cited by 38 publications

(23 citation statements)

References 89 publications

(15 reference statements)

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“…The structures clearly show the new C−Si and Pt−Si bonds formed, with the bond distance in the latter being almost identical to that in 2.1 a (2.2609(8) and 2.2619(6) Å for 2.2 a and 2.2 b , respectively). The seven‐membered metalacycle is in a boat conformation, as previously observed in cobalt and iron systems reported by Deng . All these compounds are very stable both in solution and in the solid state, even under air.…”

Section: Resultssupporting

confidence: 74%

σ‐Silane Platinum(II) Complexes as Intermediates in C−Si Bond‐Coupling Processes

Ríos

Fouilloux

Dı́ez

et al. 2019

Chemistry A European J

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Platinumc omplexes [Pt(NHC')(NHC)][BAr F ]( in which NHC' denotes ac yclometalated N-heterocyclic carbene ligand, NHC) react with primary silanes RSiH 3 to afford the cyclometalated platinum(II) silyl complexes [Pt(NHC-SiHR')(NHC)][BAr F ]t hrough ap rocess that involves the formation of CÀSi and PtÀSi bonds with concomitante xtrusion of H 2 .L ow-temperature NMR studies indicatet hat the process proceeds through initial formation of the s-SiH complexes [Pt(NHC')(NHC)(HSiH 2 R)][BAr F ], which are stable at temperatures below À10 8C. At highert emperatures, activation of one SiÀHb ond followed by aC ÀSi coupling reaction generates an agostic SiH platinum hydride derivative [Pt(H)(NHC'-SiH 2 R)(NHC)][BAr F ], whichu ndergoes as econd SiÀHb ond activation to afford the final products. Computationalm odeling of the reaction mechanism indicates that the stereochemistry of the silyl/hydride ligands after the first SiÀHb ond cleavage dictates the nature of the products, favoringthe formation of aC ÀSi bond over aC ÀHb ond, in contrastt op revious results obtained for tertiary silanes. Furthermore, the processi nvolves a trans-to-cis isomerization of the NHC ligand beforet he second SiÀHbond cleavage.

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Section: Resultssupporting

confidence: 74%

σ‐Silane Platinum(II) Complexes as Intermediates in C−Si Bond‐Coupling Processes

Ríos

Fouilloux

Dı́ez

et al. 2019

Chemistry A European J

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“…Very recently, Deng and co-workers presented another type of cobalt(III) complexes supported by NHC−silyl−NHC ligands. 307 Silyl-functionalized NHCs are thought to have pronounced electron-donating properties. However, the incompatibility of the Lewis acidic silanes with nucleophilic NHC ligands renders the direct synthesis of this type of ligand difficult.…”

Section: Complexes Of Cobaltmentioning

confidence: 99%

“…Pincer-type ligands possess the important features of strong electron-donation and high rigidity, which are useful for the synthesis of reactive transition metal species and also new catalyst design. − On the basis of these factors, there is high interest in cobalt complexes supported by NHC-based pincer ligands. ,− As the representative study in this area, Fout found that the bis(NHC)-aryl ligand 2,6-bis( N -arylbenzimidazol-2-ylidene)phenyl ( Ar CCC-2) was able to support cobalt(I, II, and III) species that are useful catalysts for the hydro-functionalization of olefins. , As the preparation of the bis(NHC)-aryl lithium salts from the reactions of the bis(NHC)benzene with Bu n Li was unsuccessful, the author developed a one-pot metalation procedure, the reactions of the 1,3-benzene-bridged di(benzimidazolium) salts [H 3 ( Ar CCC-2)]Cl 2 with [Co(N(SiMe 3 ) 2 ) 2 (py) 2 ], LiN(SiMe 3 ) 2 , and ClCPh 3 . Using this protocol, the green pincer complexes [( Ar CCC-2)CoCl 2 (py)] (Ar = Dipp, 138 ; Mes, 139 ) were prepared in high yields (Scheme ).…”

Section: High-oxidation-state 3d Metal Complexes With Nhc Ligationmentioning

confidence: 99%

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High-Oxidation-State 3d Metal (Ti–Cu) Complexes withN-Heterocyclic Carbene Ligation

et al. 2018

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High-oxidation-state 3d metal species have found a wide range of applications in modern synthetic chemistry and materials science. They are also implicated as key reactive species in biological reactions. These applications have thus prompted explorations of their formation, structure, and properties. While the traditional wisdom regarding these species was gained mainly from complexes supported by nitrogen- and oxygen-donor ligands, recent studies with N-heterocyclic carbenes (NHCs), which are widely used for the preparation of low-oxidation-state transition metal complexes in organometallic chemistry, have led to the preparation of a large variety of isolable high-oxidation-state 3d metal complexes with NHC ligation. Since the first report in this area in the 1990s, isolable complexes of this type have been reported for titanium(IV), vanadium(IV,V), chromium(IV,V), manganese(IV,V), iron(III,IV,V), cobalt(III,IV,V), nickel(IV), and copper(II). With the aim of providing an overview of this intriguing field, this Review summarizes our current understanding of the synthetic methods, structure and spectroscopic features, reactivity, and catalytic applications of high-oxidation-state 3d metal NHC complexes of titanium to copper. In addition to this progress, factors affecting the stability and reactivity of high-oxidation-state 3d metal NHC species are also presented, as well as perspectives on future efforts.

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“…In this context, silyl ligands are of particular interest due to their strong σ‐donor ability, which enables them to generate electron‐rich metal sites and concomitantly labilize trans substituents . To date, monoanionic silyl ligands that feature pendant donor groups (Scheme , left) such as phosphine, pyridine, quinoline, olefin, and N ‐heterocyclic carbenes (NHCs) moieties,, have been developed and applied in transition‐metal (TM)‐mediated activation of inert bonds (i.e., H−H, N−H, C−H, N≡N) in catalysis . N‐Heterocyclic silylenes (NHSis), the heavy analogues of NHCs, represent a new type of stronger σ‐donors than NHCs and phosphines that have already been demonstrated to be effective in homogeneous catalysis .…”

Section: Methodsmentioning

confidence: 99%

Chelate Silylene–Silyl Ligand Can Boost Rhodium‐Catalyzed C−H Bond Functionalization Reactions

Kostenko

Zhou

et al. 2018

Chemistry A European J

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The first N-heterocyclic silylene (NHSi)-silane scaffold LSi-R-Si(H)Mes (1) (L=PhC(NtBu) ; R=1,12-xanthendiyl spacer; Mes=2,4,6-Me C H ) was synthesized and used to form the unique rhodium(III) complex (LSi-R-SiMes )Rh(H)Cl 2 through its reaction with 0.5 molar equivalents of [Rh(coe) Cl] (coe=cyclooctene). An X-ray diffraction analysis revealed that 2 has a (Si Si )Rh(H)Cl core with three short Rh⋅⋅⋅H-C contacts with Me groups of the ligand 1, which cause a distorted pentagonal bipyramidal coordination of the Rh center. Unexpectedly, the reaction of 2 with tBuONa gives the new bis(silyl)hydridorhodium(III) complex 4. Due to the strong donor ability of the chelate Si -Si ligand, 2 and 4 can act as highly efficient pre-catalysts in the Rh-mediated selective C-H functionalization of 2-phenylpyridines with C-C unsaturated organic substrates under mild reaction conditions.

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An NHC–Silyl–NHC Pincer Ligand for the Oxidative Addition of C−H, N−H, and O−H Bonds to Cobalt(I) Complexes

Cited by 38 publications

References 89 publications

σ‐Silane Platinum(II) Complexes as Intermediates in C−Si Bond‐Coupling Processes

σ‐Silane Platinum(II) Complexes as Intermediates in C−Si Bond‐Coupling Processes

High-Oxidation-State 3d Metal (Ti–Cu) Complexes withN-Heterocyclic Carbene Ligation

Chelate Silylene–Silyl Ligand Can Boost Rhodium‐Catalyzed C−H Bond Functionalization Reactions

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