Real Time Characterization of Catalysis by On-Line Electrochemistry/Mass Spectrometry. Investigation of Quinone Electrocatalysis of Amine Oxidation

Regino, Merle C.S.; Brajter-Toth, Anna

doi:10.1002/(sici)1521-4109(199905)11:5<374::aid-elan374>3.0.co;2-8

Cited by 23 publications

(5 citation statements)

References 30 publications

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“…[30][31][32][33][34][35][36][37][38][39] A notable advantage of the radial configuration [21][22][23] is the ability to accurately control the conversion in the cell, and by using a thin layer cell one can also obtain full conversion of the reactants with minimal ohmic drop.…”

Section: Resultsmentioning

confidence: 99%

“…Preparative electrochemistry of ruthenium complexes, followed by ESI-MS product analysis of reaction products has been extensively studied by Bond et al 28,29 However, direct on-line coupling of the electrochemical cell to the ESI-MS provides several additional advantages, including the minimization of anode-cathode crosstalk and quenching of consecutive homogeneous reactions following the electrochemical transformations. [30][31][32][33][34][35][36][37][38][39] A notable advantage of the radial configuration [21][22][23] is the ability to accurately control the conversion in the cell, and by using a thin layer cell one can also obtain full conversion of the reactants with minimal ohmic drop.…”

Section: Resultsmentioning

confidence: 99%

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Electro-oxidation of Ruthenium Cyclopentadienyl PTA Complexes in DMF

Gutkin

Gun

Prikhodchenko

et al. 2007

J. Electrochem. Soc.

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Halogen complexes of ruthenium cyclopentadienyl ͓CpRu͑PTA͒ 2 X͔; ͓CpRu͑PTA͒͑PPh 3 ͒X͔; ͓CpRu͑PPh 3 ͒ 2 Cl͔, and ͓CpRu͑mPTA͒͑PPh 3 ͒X͔ + ͑Cp = C 5 H 5 ; PTA = 1,3,5-triaza-7-phosphaadamantane; mPTA + = ͓1-methyl-1,3,5-triaza-7-phosphaadamantane͔ + ; X = Cl − , I − ͒ were investigated by electrospray mass spectrometry ͑ESI-MS͒, in flow-cell cyclic voltammetry, by microelectrodes, and by combined online electrochemistry and electrospray mass spectrometry ͑EC/ESI-MS͒ in dimethyl formamide solution. Coordination changes and the structures of the initial compounds and the products of the electrooxidation of the Ru͑II͒ complexes were traced by in situ EC/MS n experiments which revealed their fragmentation pathways. ESI-MS collision-induced dissociation fragmentations of the initial reactants and the oxidation products were explained by soft acid-hard base considerations taking into account the different nature of Ru͑II͒-Ru͑IV͒ centers. The electrochemical studies show that it is possible to tune the formal potentials for the oxidation of ͓CpRuL 2 X͔ complexes by over 300 mV by proper selection of the ligands. The increase of the redox potential by the different ligands follows the order PTA Ͻ PPh 3 Ͻ mPTA + . We demonstrate a similarity between the propensity of the ligand to fragment out in the gas phase and its relationship to the formal potential of the complex.The use of neutral water-soluble monodentate phosphines such as 1,3,5-triaza-7-phosphaadamantane ͑PTA͒ has received renewed interest in the recent literature due to its ability to solubilize transition metal complexes in the aqueous phase. This property has been used for aqueous phase or biphasic homogeneous catalysis of Rh, Ru, and Pd-PTA complexes, in tests as new drugs for tumor inhibition ͑Ru-and Pt-PTA͒ and in photoluminescent devices ͑Au-PTA͒. 1 Other interesting characteristics of PTA are the ability to bridge different transition metals both via P and N donor atoms, to create complex water soluble organometallic networks, 2 and to selectively functionalize either P or N, for example by attack from BH 3 . 3,4 Ru͑II͒, Rh͑I͒, and Rh͑III͒ complexes of N-methyl-PTA ͑PTA-Me͒ such as trans-͓RuI 4 ͑PTA-Me͒ 2 ͔, ͓RuI 2 ͑PTA-Me͒ 3 ͑H 2 O͔͒I 3 , and ͓RhI 4 ͑PTA-Me͒ 2 ͔I are active catalysts for the hydrogenation of cinnamaldehyde 5 at the C v O bond for Ru, and at the C v C double bond for Rh. Also these complexes were found to be active in DNA binding studies. 6 The synthesis of the new rhenium pentahydride complex ͓ReH 5 ͑PPh 3 ͒ 2 ͑PTA͔͒ and its characterization by X-ray diffraction analysis, variable temperature infrared ͑IR͒ and nuclear magnetic resonance ͑NMR͒ experiments, including T 1 analysis and protonation studies was also recently described. 7

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Electro-oxidation of Ruthenium Cyclopentadienyl PTA Complexes in DMF

Gutkin

Gun

Prikhodchenko

et al. 2007

J. Electrochem. Soc.

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“…The catalytic and electrocatalytic oxidation of aliphatic amines with reversible redox couple acting as a mediator has been much less investigated. − However, it has the advantage to decrease the overpotential needed for the oxidation of amines, as well as to minimize the surface fouling effect on the working electrodes . This correspondingly increases the sensitivity and enhances the reliability and reproducibility of the obtained data.…”

Section: Introductionmentioning

confidence: 99%

Electrocatalytic Dealkylation of Amines Mediated by Ferrocene

2019

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The homogeneous catalytic oxidation of dicyclohexylamine (DCHA), N,N-dimethylcyclohexylamine (DMCHA) and N,N-dicyclohexylmethylamine (DCHMA) has been investigated in the presence of electrochemically generated ferrocenium ions as the catalyst. Mechanistic details for this electrocatalytic process have been scrutinized with the use of cyclic voltammetry, bulk electrolysis, and digital simulations techniques. A one-electron catalytic process between ferrocene and the respective amines was observed. The products obtained from bulk electrolysis were isolated and identified by FTIR, 1H and 13C NMR spectroscopy, and mass spectrometry. Both DCHMA and DMCHA proceed to yield a secondary amine product by the elimination of one methyl group. In the absence of this group, as in the case of DCHA, the cycloalkyl group is then eliminated. The catalytic efficiency and the second-order rate constants were estimated and found to follow the order DCHA ≪ DMCHA < DCHMA. The results presented in this work should open up a new avenue to achieve simple, low-cost, and efficient amine oxidation, which could be useful in several areas of chemistry.

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“…We refer the interested reader to a selection of published reviews pertaining to electrospray ionization and/or EC/ESI coupling available elsewhere . The focus in the current paper is kept on features of electrochemistry/ electrospray that have been largely neglected but might be important for analytical practice, especially if one considers how the development of electrochemical derivatization of analytes has become an established and fruitful method [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38].…”

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confidence: 99%

Perspective on Electrospray Ionization and Its Relation to Electrochemistry

Pozniak

Cole

2015

J. Am. Soc. Mass Spectrom.

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A VAbstract. The phenomenon of electrospraying of liquids is presented from the perspective of the electrochemistry involved. Basics of current and liquid flow in the capillary and spray tip are discussed, followed by specifics of charging and discharging of the sprayed liquid surface. Fundamental theories and numerical modeling relating electrospray current to solution and spray parameters are described and then compared with our own experimentally obtained data. The method of mapping potentials and currents inside the electrospray capillary by using an inserted electrically-isolated small wire probe electrode is discussed in detail with illustrations from new and published data. Based on these experimentally obtained results, a new mathematical model is derived. The introduced "nonlinear resistor electrospray capillary model" divides the electrospray capillary into small sections, adds their contributions, and then, by transition to infinitely small section thickness, produces analytical formulas that relate current and potential maps to other properties of the electrospraying liquid: primarily conductivity and current density. The presentation of the model is undertaken from an elementary standpoint, and it offers the possibility to obtain quantitative information regarding operating parameters from typical analytical systems subjected to electrospray. The model stresses simplicity and ease of use; examples applying experimental data are shown and some predictions of the model are also presented. The developed nonlinear resistor electrospray capillary model is intended to provide a new quantitative basis for improving the understanding of electrochemical transformations occurring in the electrospray emitter. A supplemental material section gives full derivation of the model and discusses other consequences.

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Real Time Characterization of Catalysis by On-Line Electrochemistry/Mass Spectrometry. Investigation of Quinone Electrocatalysis of Amine Oxidation

Cited by 23 publications

References 30 publications

Electro-oxidation of Ruthenium Cyclopentadienyl PTA Complexes in DMF

Electro-oxidation of Ruthenium Cyclopentadienyl PTA Complexes in DMF

Electrocatalytic Dealkylation of Amines Mediated by Ferrocene

Perspective on Electrospray Ionization and Its Relation to Electrochemistry

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