Bis(imino)acenaphthene (BIAN)-supported palladium(<scp>ii</scp>) carbene complexes as effective C–C coupling catalysts and solvent effects in organic and aqueous media

Crawford, Katherine A.; Cowley, Alan H.; Humphrey, Simon M.

doi:10.1039/c4cy00192c

Cited by 16 publications

(11 citation statements)

References 47 publications

(61 reference statements)

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“…In the literature, there are not available apparent information about activation energy of the heterogeneous catalyzed Suzuki reaction of Brac and FBA in aqueous media. Crawford et al synthesized 1,2‐acenaphthenyl NHC‐supported palladium(II) catalysts ((BIAN)‐supported palladium(II) carbene complexes) and used them in heterogeneous catalyzed Suzuki reaction of bromobenzaldehyde and FBA in aqueous media . The activation energies of these catalytic systems were determined to be in the range of 111‐116 kJ mol −1 .…”

Section: Resultsmentioning

confidence: 99%

“…Crawford et al synthesized 1,2-acenaphthenyl NHC-supported palla-dium(II) catalysts ((BIAN)-supported palladium(II) carbene complexes) and used them in heterogeneous catalyzed Suzuki reaction of bromobenzaldehyde and FBA in aqueous media. 48 The activation energies of these catalytic systems were determined to be in the range of 111-116 kJ mol −1 . When these results compared with the present study, it can be seen that activation energies which determined by Crawford and co-workers are significantly larger than the poly(AAm-co-AMPS)-based NHC-Pd-pyridine catalyzed Suzuki reaction of Brac and FBA.…”

Section: Activation Energymentioning

confidence: 99%

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The kinetics and mechanism of polymer‐based NHC‐Pd‐pyridine catalyzed heterogeneous Suzuki reaction in aqueous media

Boztepe

Künkül

Gürbüz

et al. 2019

Int J of Chemical Kinetics

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One of the most important challenges of the Suzuki reaction is a green synthesis of reaction products. In terms of economy and ecology, the Suzuki reaction details must be characterized for the industrial‐scale Suzuki reaction processes. In this paper, for the first time, a kinetic and mechanistic study on the Suzuki reaction catalyzed with hydrogel‐supported PEPPSI (pyridine‐enhanced precatalyst preparation stabilization (and) initiation) type NHC‐Pd‐pyridine composite has been investigated. To determine the rate‐limiting step, the effects of reactants and experimental conditions on the heterogeneous Suzuki reaction have been experimentally defined. The experimental results demonstrated that it is possible to reach 100% yield under the optimum reaction conditions, which were found as 75 × 10−3 mol/L of phenylboronic acid (FBA), 50 × 10−3 mol/L of bromoacetophenone (Brac), 125 × 10−3 mol/L of K2CO3, 1 g/L of catalyst, 80°C of reaction temperature, 400 rpm of mixing rate, and 3 h of reaction time. The transmetalation step in the cycle was defined as the rate‐limiting step. On the basis of kinetic results, a mathematical reaction rate expression was presented assuming the steady‐state approach to steps of the catalytic cycle. The activation energy (Ea) of the reaction was estimated to be 34.88 kJ/mol.

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Section: Resultsmentioning

confidence: 99%

Section: Activation Energymentioning

confidence: 99%

The kinetics and mechanism of polymer‐based NHC‐Pd‐pyridine catalyzed heterogeneous Suzuki reaction in aqueous media

Boztepe

Künkül

Gürbüz

et al. 2019

Int J of Chemical Kinetics

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“…In 2014, Humphrey and co‐workers reported mixed NHC/phosphine [Pd(BIAN‐NHC)(PPh 3 )Cl 2 ] complexes 8 – 9 and evaluated their reactivity in the Suzuki–Miyaura cross‐coupling of aryl halides under aqueous conditions (Scheme 5). [35] The performance of catalysts 8 – 9 was also evaluated in non‐polar solvents. Interestingly, it was found that water and toluene promoted catalyst decomposition to yield a new heterogeneous species, while both catalysts were considerably more stable in dichloromethane.…”

Section: Palladium‐bian‐nhc Complexesmentioning

confidence: 99%

BIAN‐NHC Ligands in Transition‐Metal‐Catalysis: A Perfect Union of Sterically Encumbered, Electronically Tunable N‐Heterocyclic Carbenes?

Chen

Liu

Szostak

2021

Chemistry A European J

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The discovery of NHCs (NHC = N‐heterocyclic carbenes) as ancillary ligands in transition‐metal‐catalysis ranks as one of the most important developments in synthesis and catalysis. It is now well‐recognized that the strong σ‐donating properties of NHCs along with the ease of scaffold modification and a steric shielding of the N‐wingtip substituents around the metal center enable dramatic improvements in catalytic processes, including the discovery of reactions that are not possible using other ancillary ligands. In this context, although the classical NHCs based on imidazolylidene and imidazolinylidene ring systems are now well‐established, recently tremendous progress has been made in the development and catalytic applications of BIAN‐NHC (BIAN = bis(imino)acenaphthene) class of ligands. The enhanced reactivity of BIAN‐NHCs is a direct result of the combination of electronic and steric properties that collectively allow for a major expansion of the scope of catalytic processes that can be accomplished using NHCs. BIAN‐NHC ligands take advantage of (1) the stronger σ‐donation, (2) lower lying LUMO orbitals, (3) the presence of an extended π‐system, (4) the rigid backbone that pushes the N‐wingtip substituents closer to the metal center by buttressing effect, thus resulting in a significantly improved control of the catalytic center and enhanced air‐stability of BIAN‐NHC‐metal complexes at low oxidation state. Acenaphthoquinone as a precursor enables facile scaffold modification, including for the first time the high yielding synthesis of unsymmetrical NHCs with unique catalytic properties. Overall, this results in a highly attractive, easily accessible class of ligands that bring major advances and emerge as a leading practical alternative to classical NHCs in various aspects of catalysis, cross‐coupling and C−H activation endeavors.

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“…Nevertheless, enormous progress has been made improving the efficiency of Suzuki catalysts and extremely high turnover frequencies and turnover number can be achieved and the nature of the solvent plays an important role with respect to catalyst stability. 58 The active catalyst in the Suzuki reaction is based on a palladiumĲ0) species ( Fig. 15 shows a generic mechanism for the reaction).…”

Section: C-c Coupling Reactionsmentioning

confidence: 99%

Solvent effects in catalysis: rational improvements of catalysts via manipulation of solvent interactions

Dyson

Jessop

2016

Catal. Sci. Technol.

274

229

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Bis(imino)acenaphthene (BIAN)-supported palladium(ii) carbene complexes as effective C–C coupling catalysts and solvent effects in organic and aqueous media

Abstract: Significant solvent effects in the Suzuki–Miyaura coupling reaction are described for the case of two new N-heterocyclic carbene-supported palladium(ii) complexes.

Cited by 16 publications

References 47 publications

The kinetics and mechanism of polymer‐based NHC‐Pd‐pyridine catalyzed heterogeneous Suzuki reaction in aqueous media

The kinetics and mechanism of polymer‐based NHC‐Pd‐pyridine catalyzed heterogeneous Suzuki reaction in aqueous media

BIAN‐NHC Ligands in Transition‐Metal‐Catalysis: A Perfect Union of Sterically Encumbered, Electronically Tunable N‐Heterocyclic Carbenes?

Solvent effects in catalysis: rational improvements of catalysts via manipulation of solvent interactions

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