C–CN Bond Activation of Benzonitrile with [Rh<sup>–I</sup>(dippe)]<sup>−</sup>

Grochowski, Matthew R.; Morris, James; Brennessel, William W.; Jones, William D.

doi:10.1021/om200342f

Cited by 27 publications

(10 citation statements)

References 26 publications

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“…Considering that the oxidative additions of phenyl chloride, benzyl chloride, and benzonitrile to a Ni 0 complex have been experimentally reported and theoretically analyzed, − we tried to locate a related Ni II hydride phenyl propene complex where the H(hydride) is cis to the phenyl group but failed to optimize such a structure. This agrees with previous works. , …”

Section: Resultsmentioning

confidence: 99%

“…The concerted oxidative addition of a σ bond to a Ni 0 atom has been analyzed in many experimental and theoretical studies. − Thus, we focus here on the ligand-to-ligand H transfer and address the following points. (i) Why is the ligand-to-ligand H transfer preferred over the usual concerted oxidative addition of C–H bond in the case of Ni 0 catalysts?…”

Section: Introductionmentioning

confidence: 99%

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Aromatic C–H σ-Bond Activation by Ni⁰, Pd⁰, and Pt⁰ Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

et al. 2017

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C−H σ-bond activation of arene (represented here by benzene) by the Ni 0 propene complex Ni 0 (IMes)-(C 3 H 6 ) (IMes = 1,3-dimesitylimidazol-2-ylidene), which is an important elementary step in Ni-catalyzed hydroarylation of unactivated alkene with arene, was investigated by DFT calculations. In the Ni 0 complex, the C−H activation occurs through a ligand-to-ligand H transfer mechanism to yield Ni II (IMes)(C 3 H 7 )(Ph) (C 3 H 7 = propyl; Ph = phenyl). In Pd 0 and Pt 0 analogues, the activation occurs through concerted oxidative addition of the C−H bond to the metal. Analysis of the electron redistribution during the C−H activation highlights the difference between the two mechanisms. In the ligand-toligand H transfer, charge transfer (CT) occurs from the metal to the benzene. However, the atomic population of the transferring H remains almost constant, suggesting that different CT simultaneously occurs from the transferring H to the LUMO of propene. The electron redistribution contrasts significantly with that found for Pd 0 and Pt 0 , in which CT occurs only from the metal to the benzene. Preference for ligand-to-ligand H transfer over concerted oxidative addition in the Ni 0 complex is shown to be due to the smaller atomic radius of Ni in comparison to those of Pd and Pt and the smaller Ni II −H bond energy relative to the Pd II −H and Pt II −H energies. Interestingly, the bulky ligand accelerates the ligand-to-ligand H transfer in the Ni 0 complex by decreasing the distance between the coordinated benzene and alkene substrates. Thus, the Gibbs activation energy (ΔG°⧧) decreases in the case of cyclic-alkylaminocarbene with bulky substituents (CACC-K3), while the ΔG°⧧ values are similar in X-Phos, IMes, and nonsubstituted cyclic alkylaminocarbene (CAAC-K0). An electron-withdrawing substituent on the arene accelerates the C−H activation by favoring the metal to arene CT.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aromatic C–H σ-Bond Activation by Ni⁰, Pd⁰, and Pt⁰ Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

et al. 2017

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“…The 31 P{ 1 H} SSNMR spectrum (158 K, Figure D) of hydrogenated microcrystalline [1-NBD][BAr H 4 ] (2 bar, 1 h, 298 K), features a single very broad resonance centered at δ 89.0, which is assigned to the amorphous zwitterionic decomposition product [1-BAr H 4 ] , which has been independently prepared (Supporting Information). Zwitterionic complexes such as Rh(PR 3 ) 2 {(η 6 -C 6 H 5 )BAr H 3 } are well-known. − No signals were observed that could be assigned to a σ-alkane complex. For [1-NBD][BAr F 4 ] , after hydrogenation for 1 h, two broad closely spaced downfield doublets where observed [δ 105.1, J (RhP) ≈ 180 Hz; δ 102.2, J (RhP) ≈ 190 Hz] that are assigned to σ-alkane complex [1-NBA][BAr F 4 ] .…”

Section: Resultsmentioning

confidence: 99%

Controlling Structure and Reactivity in Cationic Solid-State Molecular Organometallic Systems Using Anion Templating

et al. 2018

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The role that the supporting anion has on the stability, structure, and catalytic performance, in solid-state molecular organometallic systems (SMOM) based upon [Rh-(Cy 2 PCH 2 CH 2 PCy 2)(η 2 η 2-NBD)][BAr X 4 ], [1-NBD][BAr X 4 ], is reported (X = Cl, F, H; NBD = norbornadiene). The tetra-aryl borate anion is systematically varied at the 3,5-position, Ar X = 3,5-X 2 C 6 H 3 , and the stability and structure in the solid-state compared with the previously reported [1-NBD][BAr CF3 4 ] complex. Single-crystal X-ray crystallography shows that the three complexes have different packing motifs, in which the cation sits on the shared face of two parallelepipeds for [1-NBD][BAr Cl 4 ], is surrounded by eight anions in a gyrobifastigium arrangement for [1-NBD][BAr F 4 ], or the six anions show an octahedral cage arrangement in [1-NBD][BAr H 4 ], similar to that of [1-NBD][BAr CF3 4 ]. C−X•••X−C contacts, commonly encountered in crystal-engineering, are suggested to be important in determining structure. Addition of H 2 in a solid/gas reaction affords the resulting σ-alkane complexes, [Rh(Cy 2 PCH 2 CH 2 PCy 2)(η 2 η 2-NBA)][BAr X 4 ] [1-NBA][BAr X 4 ] (NBA = norbornane), which can then proceed to lose the alkane and form the zwitterionic, anion-coordinated, complexes. The relative rates at which hydrogenation and then decomposition of σ-alkane complexes proceed are shown to be anion dependent. [BAr CF3 4 ] − promotes fast hydrogenation and an indefinitely stable σ-alkane complex. With [BAr H 4 ] − hydrogenation is slow and the σ-alkane complex so unstable it is not observed. [BAr Cl 4 ] − and [BAr F 4 ] − promote intermediate reactivity profiles, and for [BAr Cl 4 ] − , a single-crystal to single-crystal hydrogenation results in [1-NBA][BAr Cl 4 ]. The molecular structure derived from X-ray diffraction reveals a σalkane complex in which the NBA fragment is bound through two exo Rh•••H−C interactions-different from the endo selective binding observed with [1-NBA][BAr CF3 4 ]. Periodic DFT calculations demonstrate that this selectivity is driven by the microenvironment dictated by the surrounding anions. [1-NBA][BAr X 4 ] are catalysts for gas/solid 1-butene isomerization (298 K, 1 atm), and their activity can be directly correlated to the stability of the σ-alkane complex compared to the anion-coordinated decomposition products.

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“…The mechanisms of these reactions with Co complexes remain elusive. d 10 monomeric [(dippe)Rh] −1 also undergoes the oxidative addition of benzonitrile, 37 while photoirradiation of Cp*Rh(PMe 3 )H 2 (Cp* = η 5 -pentamethylcyclopentadienyl) and Tp'Rh(PMe 3 )H 2 (Tp' = hydrotris(3,5-dimethylpyrazol-1yl)borate) allow that of acetonitrile after kinetically favored C− H activation at the Rh(I) center. 23,38,39 It is unlikely that η 2coordination of the cyano group to the Rh centers occurs, contrasting with the reactions of Ni(0) and Pd(0) because an η 2nitrile complex locates at the energy level higher than that of the C−H activation product and a low-energy pathway from the η 2nitrile complex to either the C−H or C−CN activation is not evident according to DFT calculations.…”

Section: Mechanism Of C−cn Bond Activationmentioning

confidence: 99%

Metal-mediated C–CN Bond Activation in Organic Synthesis

Nakao

2020

Chem. Rev.

109

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Nitriles are ubiquitous versatile building blocks in organic synthesis. Common reactions of nitriles include the transformation of cyano groups into carbonyl and amine moieties. The functionalization of nitriles can also be accomplished at the alpha-position of alkanenitriles and at the ortho-position of cyanoarenes. On the other hand, the C–CN bond of nitriles has rarely been recognized as a valuable reaction site due to its thermodynamic robustness. Although it has been known for a long time in organometallic chemistry that C–CN bonds can be cleaved by transition-metal complexes, this elemental reaction had not been used in catalytic synthetic transformations of nitriles until two decades ago. This review surveys the progress of metal-catalyzed reactions of nitriles via C–CN bond activation. After introducing several different modes to activate C–CN bonds by various transition metals, catalytic reactions are categorized mainly into two parts: (i) reactions with CN as a leaving group and (ii) reactions with nitriles as a source of CN groups. Cross-coupling-type transformations with a cyano leaving group, cyanation reactions using nitriles as a nontoxic cyano source, and novel synthetic reactions such as carbocyanation are highlighted together with useful demonstrations of their utility in organic synthesis.

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C–CN Bond Activation of Benzonitrile with [Rh^–I(dippe)]⁻

Cited by 27 publications

References 26 publications

Aromatic C–H σ-Bond Activation by Ni⁰, Pd⁰, and Pt⁰ Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

Aromatic C–H σ-Bond Activation by Ni⁰, Pd⁰, and Pt⁰ Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

Controlling Structure and Reactivity in Cationic Solid-State Molecular Organometallic Systems Using Anion Templating

Metal-mediated C–CN Bond Activation in Organic Synthesis

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C–CN Bond Activation of Benzonitrile with [Rh–I(dippe)]−

Cited by 27 publications

References 26 publications

Aromatic C–H σ-Bond Activation by Ni0, Pd0, and Pt0 Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

Aromatic C–H σ-Bond Activation by Ni0, Pd0, and Pt0 Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

Controlling Structure and Reactivity in Cationic Solid-State Molecular Organometallic Systems Using Anion Templating

Metal-mediated C–CN Bond Activation in Organic Synthesis

Contact Info

Product

Resources

About

C–CN Bond Activation of Benzonitrile with [Rh^–I(dippe)]⁻

Aromatic C–H σ-Bond Activation by Ni⁰, Pd⁰, and Pt⁰ Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism

Aromatic C–H σ-Bond Activation by Ni⁰, Pd⁰, and Pt⁰ Alkene Complexes: Concerted Oxidative Addition to Metal vs Ligand-to-Ligand H Transfer Mechanism