Electrochemical Oxidation of Methanol with Ru/Pd, Ru/Pt, and Ru/Au Heterobimetallic Complexes

Abstract

The heterobimetallic complexes CpRu(PPh3)(μ-Cl)(μ-dppm)PdCl2 (1) [dppm = bis(diphenylphosphino)methane], CpRu(PPh3)Cl(μ-dppm)AuCl (2), and CpRu(PPh3)(μ-Cl)(μ-dppm)PtCl2 (3) were synthesized by the reaction of CpRu(PPh3)Cl(η1-dppm) (4) with Pd(COD)Cl2, AuPPh3Cl, and Pt(COD)Cl2, respectively. Compounds 1 and 2 were characterized by X-ray crystallography. Electrochemical oxidation of CH3OH in the presence of 1, 2, or 3 leads to considerable enhancement of the oxidative currents and formation of the organic products CH2(OCH3)2 and HCOOCH3. Addition of water increases both the current and the proportion of the more highly oxidized product, HCOOCH3. Current efficiencies obtained with heterobinuclear complexes 1−3 were significantly higher than those obtained using the model compound CpRuCl(η2-dppm) (5) as catalyst.

Activity of a novel titanium-supported bimetallic PtSn/Ti electrode for electrocatalytic oxidation of formic acid and methanol

“…In order to enhance the electroactivity of pure platinum, bimetallic or ternary metal electrocatalysts containing Pt have been fabricated. Bimetallic PtRu electrocatalysts have been intensively investigated and show high activity for methanol oxidation [9][10][11][12][13][14][15][16][17][18]. Electrochemical oxidation of both methanol and formic acid on bimetallic PtIr catalysts has been carried out [9,19].…”

Electrochemical oxidation of ethanol using Nafion electrodes modified with heterobimetallic catalysts

“…1a) [17][18][19]22]. The first and third waves correspond to the II/III and III/IV oxidations of either Ru or Fe while the second wave represents the II/IV oxidation of the second metal (Pt or Pd).…”

“…In these complexes, the metals are linked through a 1,1 0 -bis(diphenylphosphino)methane (dppm) ligand which allows for a synergistic effect and increased reactivity of the complex when compared to mononuclear model compounds [18,21,22]. The electrocatalytic oxidation of methanol by the homogeneous catalysts 1-5 produces 1,1-dimethoxymethane (DMM) and methyl formate (MF) after two-and four-electron oxidation to formaldehyde and formic acid followed by condensation with excess methanol in solution [18,21,22]. The electrocatalytic oxidation of ethanol by 1-5 yields acetaldehyde and acetic acid (AA), the twoand four-electron oxidation products, as well as their respective ethanol condensates 1,1 0 -diethoxyethane (DEE) and ethyl acetate (EA) [23,24].…”

Dimerization of ethynylaniline to a quinoline derivative using a ruthenium/gold heterobimetallic catalyst

“…Solvents were passed through an MBraun MB-SP solvent purification system prior to use. The bimetallic catalysts, 1 36 and 2, 27 and 2-ethynylphenol 9 34 were prepared according to literature reports. Compounds 1, 36 2, 27 and 9 34 were characterized by comparison to literature data.…”