Transient Ru-methyl formate intermediates generated with bifunctional transfer hydrogenation catalysts

Desorption electrospray ionization (DESI) coupled to high-resolution Orbitrap mass spectrometry (MS) was used to study the reactivity of a (β-amino alcohol)(arene)RuCl transfer hydrogenation catalytic precursor in methanol (CH3OH). By placing [(p-cymene)RuCl2]2 on a surface and spraying a solution of β-amino alcohol in methanol, two unique transient intermediates having lifetimes in the submillisecond to millisecond range were detected. These intermediates were identified as Ru (II) and Ru (IV) complexes incorporating methyl formate (HCOOCH3). The Ru (IV) intermediate is not observed when the DESI spray solution is sparged with Ar gas, indicating that O2 dissolved in the solvent is necessary for oxidizing Ru (II) to Ru (IV). These proposed intermediates are supported by high-resolution and high mass accuracy measurements and by comparing experimental to calculated isotope profiles. Additionally, analyzing the bulk reaction mixture using gas chromatography-MS and nuclear magnetic resonance spectroscopy confirms the formation of HCOOCH3. These results represent an example that species generated from the (β-amino alcohol)(arene)RuCl (II) catalytic precursor can selectively oxidize CH3OH to HCOOCH3. This observation leads us to propose a pathway that can compete with the hydrogen transfer catalytic cycle. Although bifunctional hydrogen transfer with Ru catalysts has been well-studied, the ability of DESI to intercept intermediates formed in the first few milliseconds of a chemical reaction allowed identification of previously unrecognized intermediates and reaction pathways in this catalytic system.

[1]  Tony W. T. Bristow,et al.  On-line reaction monitoring by extractive electrospray ionisation. , 2011, Rapid communications in mass spectrometry : RCM.

[2]  M. Eberlin,et al.  The bridge connecting gas-phase and solution chemistries. , 2011, Angewandte Chemie.

[3]  S. Yao,et al.  Detection of intermediates for the Eschweiler-Clarke reaction by liquid-phase reactive desorption electrospray ionization mass spectrometry. , 2011, The Analyst.

[4]  Yan Liu,et al.  Development of submillisecond time-resolved mass spectrometry using desorption electrospray ionization. , 2011, Analytical chemistry.

[5]  C. Djerassi.  The Oppenauer Oxidation , 2011 .

[6]  R. Cooks,et al.  Accelerated bimolecular reactions in microdroplets studied by desorption electrospray ionization mass spectrometry , 2011 .

[7]  Allis S. Chien,et al.  Detecting reaction intermediates in liquids on the millisecond time scale using desorption electrospray ionization. , 2011, Angewandte Chemie.

[8]  A. Singh,et al.  Transfer Hydrogenation of Ketones and Catalytic Oxidation of Alcohols with Half-Sandwich Complexes of Ruthenium(II) Designed Using Benzene and Tridentate (S, N, E) Type Ligands (E = S, Se, Te) , 2010 .

[9]  S. Fukuzumi,et al.  A low-spin ruthenium(IV)-oxo complex: does the spin state have an impact on the reactivity? , 2010, Angewandte Chemie.

[10]  Shiyong Wu,et al.  The study of protein conformation in solution via direct sampling by desorption electrospray ionization mass spectrometry , 2010, Journal of the American Society for Mass Spectrometry.

[11]  A. Singh,et al.  Synthesis, characterization and reactivity of arene ruthenium compounds based on 2,2′-dipyridylamine and di-2-pyridylbenzylamine and their applications in catalytic hydrogen transfer of ketones , 2010 .

[12]  M. Wills,et al.  (1R,2S)-(+)-cis-1-Amino-2-indanol: An Effective Ligand for Asymmetric Catalysis of Transfer Hydrogenations of Ketones. , 2010 .

[13]  R. Cooks,et al.  Desorption electrospray ionization and other ambient ionization methods: current progress and preview. , 2010, The Analyst.

[14]  N. Russo,et al.  Mechanistic investigation of the hydrogenation of O(2) by a transfer hydrogenation catalyst. , 2010, Journal of the American Chemical Society.

[15]  K. Ohkubo,et al.  Mechanistic insights into hydride-transfer and electron-transfer reactions by a manganese(IV)-oxo porphyrin complex. , 2009, Journal of the American Chemical Society.

[16]  R. Waymouth,et al.  Mechanistic Studies of the Oxidative Dehydrogenation of Methanol Using a Cationic Palladium Complex , 2009 .

[17]  J. Metzger,et al.  Electron-transfer-catalyzed dimerization of trans-anethole: detection of the distonic tetramethylene radical cation intermediate by extractive electrospray ionization mass spectrometry. , 2008, Journal of the American Chemical Society.

[18]  R. Cooks,et al.  Orbitrap mass spectrometry: instrumentation, ion motion and applications. , 2008, Mass spectrometry reviews.

[19]  E. Ison,et al.  Mechanistic investigations of the iridium(III)-catalyzed aerobic oxidation of primary and secondary alcohols. , 2008, Journal of the American Chemical Society.

[20]  Jianliang Xiao,et al.  Broader, greener, and more efficient: recent advances in asymmetric transfer hydrogenation. , 2008, Chemistry, an Asian journal.

[21]  T. Ikariya,et al.  Aerobic oxidation of alcohols with bifunctional transition-metal catalysts bearing C-N chelate ligands. , 2008, Chemistry, an Asian journal.

[22]  J. Ruiz,et al.  Heterogeneous Catalysis in the Meerwein—Ponndorf—Verley Reduction of Carbonyl Compounds , 2008 .

[23]  R. Graham Cooks,et al.  Ambient desorption ionization mass spectrometry , 2008 .

[24]  Joop A. Peters,et al.  Transfer Hydrogenation Including the Meerwein‐Ponndorf‐Verley Reduction , 2008 .

[25]  T. Meyer,et al.  Proton-coupled electron transfer. , 2007, Chemical reviews.

[26]  T. Rauchfuss,et al.  Homogeneous catalytic reduction of dioxygen using transfer hydrogenation catalysts. , 2007, Journal of the American Chemical Society.

[27]  Jose Rafael Ruiz and Cesar Jimenez-Sanchidrian.  Heterogeneous Catalysis in the Meerwein-Ponndorf-Verley Reduction of Carbonyl Compounds , 2007 .

[28]  Jianliang Xiao,et al.  Aqueous-phase asymmetric transfer hydrogenation of ketones--a greener approach to chiral alcohols. , 2007, Chemical communications.

[29]  W. Nam,et al.  High-valent iron(IV)-oxo complexes of heme and non-heme ligands in oxygenation reactions. , 2007, Accounts of chemical research.

[30]  M. Eberlin.  Electrospray Ionization Mass Spectrometry: A Major Tool to Investigate Reaction Mechanisms in Both Solution and the Gas Phase , 2007, European journal of mass spectrometry.

[31]  R. Cooks,et al.  Droplet dynamics and ionization mechanisms in desorption electrospray ionization mass spectrometry. , 2006, Analytical chemistry.

[32]  Zheng Ouyang,et al.  Ambient Mass Spectrometry , 2006, Science.

[33]  Elisabetta Alberico,et al.  Asymmetric transfer hydrogenation: chiral ligands and applications. , 2006, Chemical Society reviews.

[34]  A. Makarov,et al.  Performance evaluation of a hybrid linear ion trap/orbitrap mass spectrometer. , 2006, Analytical chemistry.

[35]  R. Cooks,et al.  Ambient mass spectrometry using desorption electrospray ionization (DESI): instrumentation, mechanisms and applications in forensics, chemistry, and biology. , 2005, Journal of mass spectrometry : JMS.

[36]  A. Makarov,et al.  The Orbitrap: a new mass spectrometer. , 2005, Journal of mass spectrometry : JMS.

[37]  R. Morris,et al.  Mechanisms of the H2-hydrogenation and transfer hydrogenation of polar bonds catalyzed by ruthenium hydride complexes , 2004 .

[38]  R. Cooks,et al.  Mass Spectrometry Sampling Under Ambient Conditions with Desorption Electrospray Ionization , 2004, Science.

[39]  Peter Chen,et al.  Electrospray Ionization Tandem Mass Spectrometry in High‐Throughput Screening of Homogeneous Catalysts. , 2003 .

[40]  Peter Chen.  Electrospray ionization tandem mass spectrometry in high-throughput screening of homogeneous catalysts. , 2003, Angewandte Chemie.

[41]  Robert H Morris,et al.  Mechanism of the hydrogenation of ketones catalyzed by trans-dihydrido(diamine)ruthenium II complexes. , 2002, Journal of the American Chemical Society.

[42]  R. Noyori,et al.  Metal-ligand bifunctional catalysis: a nonclassical mechanism for asymmetric hydrogen transfer between alcohols and carbonyl compounds. , 2001, The Journal of organic chemistry.

[43]  Ryoji Noyori,et al.  Asymmetric Catalysis by Architectural and Functional Molecular Engineering: Practical Chemo- and Stereoselective Hydrogenation of Ketones. , 2001, Angewandte Chemie.

[44]  Peter Chen,et al.  Fishing for Catalysts: Mechanism‐Based Probes for Active Species in Solution , 2000 .

[45]  M. Vargaftik,et al.  Giant Pd-561 clusters: onset to new catalytic properties , 1999 .

[46]  M. Wills,et al.  Asymmetric transfer hydrogenation of C=O and C=N bonds , 1999 .

[47]  T. Ikariya,et al.  The Catalyst Precursor, Catalyst, and Intermediate in the RuII‐Promoted Asymmetric Hydrogen Transfer between Alcohols and Ketones , 1997 .

[48]  and Ryoji Noyori,et al.  Asymmetric Transfer Hydrogenation Catalyzed by Chiral Ruthenium Complexes , 1997 .

[49]  V. Yachandra,et al.  Manganese Cluster in Photosynthesis: Where Plants Oxidize Water to Dioxygen. , 1996, Chemical reviews.

[50]  S. Shinoda,et al.  Mechanistic study on dehydrogenation of methanol with [RuCl2(PR3)3]-type catalyst in homogeneous solutions , 1996 .

[51]  D. Lu,et al.  Polyacrylonitrile coated silica as support for copper catalyst in methanol dehydrogenation to methyl formate , 1994 .

[52]  David A. Dixon,et al.  A local density functional study of the structure and vibrational frequencies of molecular transition-metal compounds , 1992 .

[53]  Dennis R. Salahub,et al.  Optimization of Gaussian-type basis sets for local spin density functional calculations. Part I. Boron through neon, optimization technique and validation , 1992 .

[54]  R. Noyori,et al.  BINAP: an efficient chiral element for asymmetric catalysis , 1990 .

[55]  E. C. Ashby.  Single-electron transfer, a major reaction pathway in organic chemistry. An answer to recent criticisms , 1988 .

[56]  A. Becke,et al.  Density-functional exchange-energy approximation with correct asymptotic behavior. , 1988, Physical review. A, General physics.

[57]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[58]  P. Maitlis,et al.  The Ruthenium-Catalysed Conversion of Methanol into Methyl Formate. , 1986 .

[59]  D. Trimm,et al.  Isotopic labeling studies of the mechanism of dehydrogenation of methanol to methyl formate over copper-based catalysts , 1985 .

[60]  T. Nestrick,et al.  Catalytic Transfer Hydrogenation , 1974 .

[61]  E. Miyazaki,et al.  Kinetics of the Catalytic Decomposition of Methanol, Formaldehyde and Methyl Formate over a Copper-wire Surface , 1967 .

[62]  A. Heck,et al.  The detection of intermediates in the ruthenium(II) catalysed asymmetric hydrogenation of ketones using electrospray ionisation mass spectrometry , 2000 .

[63]  K. Ohe,et al.  Palladium(II)-catalyzed oxidation of terminal alkenes to methyl ketones using molecular oxygen , 2000 .

[64]  T. Ikariya,et al.  Amino alcohol effects on the ruthenium(II)-catalysed asymmetric transfer hydrogenation of ketones in propan-2-ol , 1996 .

[65]  M. N. Vargaftik,et al.  METHANOL OXIDATION CATALYZED WITH A GIANT PALLADIUM CLUSTER , 1994 .

[66]  O. Yamamoto,et al.  Dehydrogenation of methanol to methyl formate over palladium/zinc oxide catalysts , 1991 .

[67]  John T. Groves,et al.  Reactive iron porphyrin derivatives related to the catalytic cycles of cytochrome P-450 and peroxidase. Studies of the mechanism of oxygen activation , 1988 .

[68]  E. C. Ashby.  Single electron transfer : a major reaction pathway in organic chemistry , 1984 .

[69]  Y. Pocker,et al.  Mechanism of methanol oxidation by lead tetra-acetate. The novel intermediacy of formaldehyde hemiacetal , 1974 .

[70]  D. Whittaker,et al.  Kinetics of the Meerwein-Ponndorf-Verley reaction , 1969 .