Contribution of Electrochemistry to Organometallic Catalysis

Jutand, Anny

doi:10.1021/cr068072h

Cited by 498 publications

(226 citation statements)

References 243 publications

Supporting

Mentioning

217

Contrasting

Unclassified

Order By: Relevance

“…[11] It thus became possible: 1) to observe the reaction of Ar'B(OH) 2 with trans-[ArPdXL 2 ] (L= PPh 3 ; in the presence or absence of the base) through the evolution of the reduction current of the Pd II complex, 2) to observe the formation of the intermediate [ArPdAr'L 2 ] (based on its reduction current) on the way to reductive elimination, 3) to observe and quantify the final Pd 0 complex (based on its oxidation current) that was formed after transmetalation/reductive elimination, and 4) to observe and quantify the formation of the cross-coupling product ArAr' (based on its reduction current). DMF was selected as the solvent, and OH À as a typical soluble base (introduced as nBu 4 NOH, 1 m in methanol).…”

Section: Resultsmentioning

confidence: 99%

“…(1 CN,Br ; C 0 = 1.9 mm) with PhB(OH) 2 (2 H ; bC 0 ) in the presence of PPh 3 (2 C 0 ) and OH À (aC 0 ) was followed by chronoamperometry [11] in DMF. A rotating gold disk electrode was polarized at + 0.05 V, the oxidation potential of [Pd [12] At the end of the reaction (400 s), a voltammogram obtained at a fixed gold disk electrode by scanning first towards oxidation potentials exhibited the oxidation peak of [Pd…”

Section: Kinetics Of the Reaction Of Trans-mentioning

confidence: 99%

See 1 more Smart Citation

Kinetic Data for the Transmetalation/Reductive Elimination in Palladium‐Catalyzed Suzuki–Miyaura Reactions: Unexpected Triple Role of Hydroxide Ions Used as Base

Amatore

Jutand

Duc

2011

Chemistry A European J

Self Cite

344

257

View full text Add to dashboard Cite

The mechanism of the reaction of trans-[ArPdX(PPh(3))(2)] (Ar=p-Z-C(6)H(4); Z=CN, F, H; X=I, Br, Cl) with Ar'B(OH)(2) (Ar'=p-Z'-C(6)H(4); Z'=CN, H, OMe) has been established in DMF in the presence of the base OH(-) in the context of real palladium-catalyzed Suzuki-Miyaura reactions. The formation of the cross-coupling product ArAr' and [Pd(0)(PPh(3))(3)] has been followed through the application of electrochemical techniques. Kinetic data have been obtained for the first time, with determination of the observed rate constant, k(obs), of the overall reaction. trans-[ArPdX(PPh(3))(2)] is not reactive in the absence of the base. The base OH(-) plays three roles. It favors the reaction: 1) by formation of trans-[ArPd(OH)(PPh(3))(2)], a key complex which, in contrast to trans-[ArPdX(PPh(3))(2)], reacts with Ar'B(OH)(2) (rate-determining transmetalation), and 2) by unexpected promotion of the reductive elimination from the intermediate trans-[ArPdAr'(PPh(3))(2)], which generates ArAr' and a Pd(0) species. Conversely, the base OH(-) disfavors the reaction by formation of the unreactive anionic Ar'B(OH)(3)(-). As a consequence of these antagonistic effects of OH(-), the overall reactivity is controlled by the concentration of OH(-) and passes through a maximum as the concentration of OH(-) is increased. Therefore, the base favors the rate-determining transmetalation and unexpectedly also the reductive elimination.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Kinetics Of the Reaction Of Trans-mentioning

confidence: 99%

Kinetic Data for the Transmetalation/Reductive Elimination in Palladium‐Catalyzed Suzuki–Miyaura Reactions: Unexpected Triple Role of Hydroxide Ions Used as Base

Amatore

Jutand

Duc

2011

Chemistry A European J

Self Cite

344

257

View full text Add to dashboard Cite

show abstract

“…In addition, compared with the more conventional chemical cross-coupling methods, electrochemical reactions have the advantage of providing an additional driving force (cathodic potential) for the reaction processes, which thus limits the need for additional means of activation, such as heating of the reaction medium [85][86][87][88][89].…”

Section: Electrochemical Cross-coupling Using Ni-tpy Systemsmentioning

confidence: 99%

Exploring Mechanisms in Ni Terpyridine Catalyzed C–C Cross-Coupling Reactions—A Review

2018

View full text Add to dashboard Cite

Abstract:In recent years, nickel has entered the stage for catalyzed C-C cross-coupling reactions, replacing expensive palladium, and in some cases enabling the use of new substrate classes. Polypyridine ligands have played an important role in this development, and the prototypical tridentate 2,2 :6 ,2 -terpyridine (tpy) stands as an excellent example of these ligands. This review summarizes research that has been devoted to exploring the mechanistic details in catalyzed C-C cross-coupling reactions using tpy-based nickel systems.

show abstract

“…Electrochemistry is a very powerful technique that can provide fundamental insights into reaction mechanisms of redox catalysts (23)(24)(25)(26)(27). Conventionally, a catalyst is deposited on a conducting electrode material (e.g., graphite); however, this approach does not allow site isolation of the catalysts.…”

mentioning

confidence: 99%

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

Collman

Dey

Yang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

O2 reactivity of a functional NOR model is investigated by using electrochemistry and spectroscopy. The electrochemical measurements using interdigitated electrodes show very high selectivity for 4e O2 reduction with minimal production of partially reduced oxygen species (PROS) under both fast and slow electron flux. Intermediates trapped at cryogenic temperatures and characterized by using resonance Raman spectroscopy under single-turnover conditions indicate that an initial bridging peroxide intermediate undergoes homolytic OOO bond cleavage generating a trans heme/nonheme bis-ferryl intermediate. This bis ferryl species can oxygenate 2 equivalents of a reactive substrate.C ytochrome c oxidase (CcO) and nitric oxide reductase (NOR) belong to the heme copper oxidase superfamily of enzymes (1, 2). CcO is the terminal enzyme in the respiratory chain of higher organisms, located in their mitochondrial membrane, that reduces O 2 to H 2 O as source of energy. The O 2 reduction process in CcO generates a pH gradient across the bilayer membrane, which provides the driving force for ATP synthesis. The bimetallic active site of CcO has a heme ligated to the protein by a proximal histidine ligand and a distal Cu B site coordinated by 3 histidine ligands ( Fig. 1) (3). In addition to the bimetallic site, there is a conserved tyrosine ligand covalently attached to one of the histidines coordinated to Cu B (4, 5). The NORs are the older member of the family and are found in bacteria using NO 3 Ϫ as source of energy instead of O 2 (2, 6, 7). Although there are no high-resolution crystal structures of NOR, biochemical studies and computer modeling indicate that these enzymes have a histidine-ligated heme, quite like the CcOs, and a distal Fe B , unlike Cu B in CcO, coordinated by 3 histidines ( Fig. 1) (8-10). NORs do not have the conserved tyrosine residue of CcO but have a few conserved key glutamate residues (11,12). Although the NOR enzymes are proposed to have specific proton channels, they are probably not involved in generating proton gradients (13-16).These 2 enzymes exhibit complementary reactivity toward 2 very significant diatomic molecules in nature; O 2 and NO. In eukaryotes CcO (aa 3 type) reduces O 2 to H 2 O and is reversibly but strongly inhibited by [17][18][19][20]. Several other CcOs (ba 3 , caa 3 , cbb 3 ) are reported to exhibit limited (Ͻ1%) NOR activity, i.e., reduce NO to N 2 O (7, 21). On the other hand, NORs that reduce NO to N 2 O are reversibly but strongly inhibited by O 2 , and some of them show modest (Ϸ10%) O 2 reduction activity (12). The parallels in their reactivities toward O 2 and NO and similarities in their secondary structures have led to a hypotheses regarding NOR's and CcO's similar evolutionary origins (6,22).Electrochemistry is a very powerful technique that can provide fundamental insights into reaction mechanisms of redox catalysts (23-27). Conventionally, a catalyst is deposited on a conducting electrode material (e.g., graphite); however, this approach does not allow site isola...

show abstract

Contribution of Electrochemistry to Organometallic Catalysis

Cited by 498 publications

References 243 publications

Kinetic Data for the Transmetalation/Reductive Elimination in Palladium‐Catalyzed Suzuki–Miyaura Reactions: Unexpected Triple Role of Hydroxide Ions Used as Base

Kinetic Data for the Transmetalation/Reductive Elimination in Palladium‐Catalyzed Suzuki–Miyaura Reactions: Unexpected Triple Role of Hydroxide Ions Used as Base

Exploring Mechanisms in Ni Terpyridine Catalyzed C–C Cross-Coupling Reactions—A Review

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

Contact Info

Product

Resources

About

Contribution of Electrochemistry to Organometallic Catalysis

Cited by 498 publications

References 243 publications

Kinetic Data for the Transmetalation/Reductive Elimination in Palladium‐Catalyzed Suzuki–Miyaura Reactions: Unexpected Triple Role of Hydroxide Ions Used as Base

Kinetic Data for the Transmetalation/Reductive Elimination in Palladium‐Catalyzed Suzuki–Miyaura Reactions: Unexpected Triple Role of Hydroxide Ions Used as Base

Exploring Mechanisms in Ni Terpyridine Catalyzed C–C Cross-Coupling Reactions—A Review

O 2 reduction by a functional heme/nonheme bis-iron NOR model complex

Contact Info

Product

Resources

About

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex