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Our research centers on the use of electroanalytical, chromatographic, and spectroscopic methods to investigate and elucidate the kinetics and mechanisms of reduction and oxidation processes involving organic and organometallic species at various electrodes in nonaqueous solvents. For these purposes, we utilize computer-controlled data-acquisition procedures, and we use digital simulation to model the dynamics of the electron-transfer and accompanying chemical reactions. In addition, we are employing electrocatalysis, with chemically modified electrodes and with homogeneously generated mediators, for the electrosynthesis of organic and organometallic species. Compounds whose electrochemical behavior is of particular interest include alkyl halides, aryl halides, ethylenic halides, freons, acetylenic halides, acyl halides, amines, esters, organic sulfides and disulfides, ketones, anhydrides, allenes, and cumulenes.
To characterize organic electrode processes, we use a variety of electroanalytical techniques: cyclic voltammetry, hydrodynamic voltammetry with rotating disk and ring-disk electrodes, thin-layer electrochemistry, spectroelectrochemistry, preparative-scale controlled-potential coulometry, and electrochemistry—EPR spectroscopy. Electrolysis products are separated, identified, and quantitated with the aid of gas and liquid chromatography, mass and NMR spectrometry, and gas chromatography coupled to either mass spectrometry or Fourier transform infrared spectroscopy. In many instances, starting materials as well as suspected electrolysis products must be synthesized and characterized.
Research projects presently under way include the following: (1) use of electrogenerated cobalt(I) salen and nickel(I) salen for the catalytic reduction of halogenated organic compounds; (2) reactions of electrogenerated alkylcobalt(III) salen species in the presence of nitric oxide; (3) synthesis of new Schiff-base complexes of electroactive transition metals; (4) production of aldehydes via reduction of alkyl halides by nickel(I) salen; (5) preparation of glass nanobeads modified with transition-metal catalysts; and (6) electrochemical catalysis in room-temperature ionic liquids.
"Formation of 2-(3`-oxocyclohexyl)-2-cyclohexen-1-one via reduction of 2-cyclohexen-1-one with electrogenerated nickel(I) salen," with M. S. Mubarak, M. Pagel, and L. M. Marcus. J. Org. Chem., 63, 1319 (1998).
"Catalytic reduction of iodoethane by cobalt(I) salen electrogenerated at vitreous carbon cathodes," with K. S. Alleman. J. Electroanal. Chem. Interfacial Electrochem., 451, 121 (1998).
"Cathodic reduction of diphenyl disulfide by electrogenerated cobalt(I) salen," with M. J. Samide. J. Electrochem. Soc., 145, 3374 (1998).
"Electrochemical reduction of 2-bromothiazole at carbon cathodes in dimethylformamide," with C. Ji. J. Electroanal. Chem. Interfacial Electrochem., 455, 147 (1998).
"Electrochemical behavior of 3-chloro-2,4-pentanedione in the presence of cobalt salen," with M. J. Samide. J. Pharm. Biomed. Anal., 19, 193 (1999).
"Catalytic reduction of 1,8-diiodooctane by electrogenerated cobalt(I) salen and formation of mu-(1,8-n-octyl)-bis[(salen)cobalt(III)]," with K. S. Alleman. J. Electroanal. Chem. Interfacial Electrochem., 460, 207 (1999).
"Cathodic behavior of cycloalken-1-yl-phenylsulfones. I. Competition among dimerization, cleavage, isomerization, and oligomerization," with S. Prigent, P. Cauliez, and J. Simonet. Acta Chem. Scand., 53, 892 (1999).
"Addition to activated olefins of radicals formed from reaction of alkyl halides with electrogenerated nickel(I) salen," with M. S. Mubarak. J. Saudi Chem. Soc., 3, 135 (1999).
"Production of ethylene oxide via catalytic reduction of 2-bromo- and 2-iodoethanol by cobalt(I) cyclam and nickel(I) cyclam electrogenerated at carbon cathodes," with M. A. Semones. J. Electrochem. Soc., 147, 260 (2000).
"Catalytic reduction of ethyl chloroacetate by cobalt(I) salen electrogenerated at vitreous carbon cathodes," with L. J. Klein, K. S. Alleman, J. A. Karty, and J. P. Reilly. J. Electroanal. Chem., Interfacial Electrochem., 481, 24 (2000).
"Cathodic Cleavage of Sulfones: Formation of Phenolate from Strongly Activated Aryl Sulfones," with L. J. Klein, O. Fourets, and J. Simonet. J. Electroanal. Chem., 487, 66 (2000).
"Heterogeneous Electron-Transfer Rate Constants for M2(O2CR)40/ , Where M = Mo, W, Ru, or Rh and R = Alkyl or Aryl," with M. H. Chisholm, K. C. Glasgow, L. J. Klein, and A. M. Macintosh. Inorg. Chem., 39, 4354 (2000).
"Aryl sulfones with stronly electron-withdrawing substituents; do their electrogenerated radical anions always undergo a single cleavage reaction?" with J.-F. Pilard, O. Fourets, J. Simonet, and L. J. Klein. J. Electrochem. Soc., 148 E171 (2001).
"Synthesis of 5-(w-sulfhydrylalkyl)salicylaldehydes as precursors for the preparation of alkanethiol-modifed metal sales," with C. Ji. Tetrahedron Lett., 42, 6065 (2001).
"Catalytic reduction of 6-bromo-1-hexene by nickel (1) salen electrogenerated at a glassy carbon cathodes in acetonitrile," with D. M. Fang and M.S. Mubarak. J. Electrochem. Soc., 148, E464 (2001).
"Cyclic voltammetric study of the catalytic behavior of nickel (1) salen electrogenerated at a glassy carbon electrode in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF4-)," with B.K. Sweeny. Electrochem. Commun., 3, 712 (2001).
"Electrochemical reduction of benzyl iodide, benzal bromide, and benzal chlorobromide at carbon cathodes in the presence of nitric oxide in acetonitrile," with C. Ji. J. Electronanal. Chem., 516, 39 (2001).
"Electrochemical Reduction of Halogenated Pyrimidines at Mercury Cathodes in Acetonitrile," with C. Ji and E. R. Davidson. J. Electroanal. Chem., 500, 3 (2001).
"Aryl Sulfones with Strongly Electron-Withdrawing Substituents: Do Their Electrogenerated Radical-Anions Always Undergo a Single Cleavage Reaction?" with J.-P. Pilard, O. Fourets, J. Simonet, and L. J. Klein. J. Electrochem. Soc., 148, E171 (2001).
"Synthesis of 5-(w-Sulfhydrylalkyl)salicylaldehydes as Precursors for the Preparation of Alkanethiol-modified Metal Salens," with C. Ji. Tetrahedron Lett., 42, 6065 (2001).
"Survey of the Electrochemical Behavior of Chlorinated Pyrazines, Quinoxalines, and Pyridazines at Carbon and Mercury Cathodes," with M. S. Mubarak. J. Electroanal. Chem., 507, 110 (2001).
"Cyclic Voltammetric Study of the Catalytic Behavior of Nickel(I) Salen Electrogenerated at a Glassy Carbon Electrode in an Ionic Liquid (1-Butyl-3-methylimidazolium Tetrafluoroborate, BMIMBF4-)," with B. K. Sweeny. Electrochem. Commun., 3, 712 (2001).
"Catalytic Reduction of 6-Bromo-1-hexene by Nickel(I) Salen Electrogenerated at Glassy Carbon Cathodes in Acetonitrile," with D. M. Fang and M. S. Mubarak. J. Electrochem. Soc., 148, E464 (2001).
"Electrochemical Reduction of Benzyl Iodide, Benzal Bromide, and Benzal Chlorobromide at Carbon Cathodes in the Presence of Nitric Oxide in Acetonitrile," with C. Ji. J. Electroanal. Chem., 516, 39 (2001).
"Direct and Cobalt(I) Salen-Catalyzed Reduction of 2,6-Bis(chloromethyl)pyridine at Carbon Cathodes in Acetonitrile," with C. Ji, J. A. Karty, J. P. Reilly, and M. S. Mubarak. J. Electroanal. Chem., 516, 50 (2001).
"Catalytic Reduction of 1-Bromooctane by Nickel(I) Salen Electrogenerated at a Mercury Cathode in Dimethylformamide," with A. L. Guyon, L. J. Klein, and D. M. Goken. J. Electroanal. Chem., 526, 134 (2002).
"Catalytic Reduction of Ethyl Chloroacetate by Cobalt(I) Salophen Electrogenerated at Vitreous Carbon Cathodes," with A. J. Moad, L. J. Klein, J. A. Karty, and J. P. Reilly. J. Electroanal. Chem., 531, 163 (2002).
"Cathodic Behavior of Aromatic Polythioethers: Sulfur-Containing Molecular Asterisks as Redox Mediators," with N. Gueguen-Simonet, J. Simonet, and L. J. Klein. J. Electrochem. Soc., 149, E389 (2002).
"Electroreductive Intramolecular Cyclization of a Bromo Propargyloxy Ester Catalyzed by Nickel(I) Tetramethylcyclam Electrogenerated at Carbon Cathodes in Dimethylformamide," with A. P. Esteves, D. M. Goken, L. J. Klein, M. A, Lemos, and M. J. Medeiros. J. Org. Chem., 68, 1024 (2003).
"Formation of Aldehydes and Ketones via Reduction of Alkyl Monohalides by Electrogenerated Nickel(I) Salen in Dimethylformamide in the Presence of Water, Oxygen, and Light," with P. Vanalabhpatana. Tetrahedron Lett., 44, 3245 (2003).
"Metal-Ligand Charge-Transfer Promoted Photo-Electronic Bergman Cyclization of Copper Metalloenediynes: Photochemical DNA Cleavage via C-4¢ H-Atom Abstraction," with P. J. Benites, R. C. Holmberg, D. S. Rawat, B. J. Kraft, L. J. Klein, H. H. Thorp, and J. M. Zaleski. J. Am. Chem. Soc., 125, 6434 (2003).
http://Peters.chem.indiana.edu