Carbon bases, electrogenerated

Two types of electrogenerated carbon bases have commonly been used (1) dianions derived from activated alkenes, and (2) carbanions formed by reductive cleavage of halogen compounds or by direct reduction of weak carbon acids. In both cases, the efficiency of the proton transfer reaction relies on a thermodynamically favored proton transfer or a fast follow-up reaction of the deproto-nated substrate. 

Two types of electrogenerated carbon bases are commonly used dianions derived from activated alkenes, and carbanions formed by cleavage or direct reduction of weak carbon acids. 

There are many possibilities for acidic sulphones to react with electrogenerated bases, and give specific functionalization on the a carbon. The first significant example was reported by Baizer58 when reducing sulphone 70 in the presence of oxygen. 

Catalytic processes based on the use of electrogenerated nickel(O) bipyridine complexes have been a prominent theme in the laboratories of Nedelec, Perichon, and Troupel some of the more recent work has involved the following (1) cross-coupling of aryl halides with ethyl chloroacetate [143], with activated olefins [144], and with activated alkyl halides [145], (2) coupling of organic halides with carbon monoxide to form ketones [146], (3) coupling of a-chloroketones with aryl halides to give O -arylated ketones [147], and (4) formation of ketones via reduction of a mixture of a benzyl or alkyl halide with a metal carbonyl [148]. 

S.L. Alvarez-Crespo, M.J. Lobo-Castanon, A.J. Miranda-Ordieres and P. Tunon-Blanco, Amperometric glutamate biosensor based on poly(o-phenylenediamine) film electrogenerated onto modified carbon paste electrodes, Biosens. Bioelectron., 12(8) (1997) 739-747. 

Generally, in non-nucleophilic solvents (yet in the presence of non-nucleophilic organic bases like lutidine or inorganic bases like sodium carbonate) two ways of couplings may concern electrogenerated aromatic cation radicals. Thus, with an aromatic substrate such as ArH, radical coupling [7] may compete with the addition cation radical/substrate. 

Casadei MA, Cesa S, Rossi L (2000) Electrogenerated base-promoted synthesis of organic carbonates from alcohols and carbon dioxide. Eur J Org Chem 13 2445-2448... 

Choi HN, Yoon SH, Lyu YK, Lee WY et al. (2007) Electrogenerated chemiluminese ethanol biosensor based on carbon nanotube-titania-nafion composite film. Electroanalysis. 19 459 65. 

Zhuang YF, Zhang DM, Ju HX (2005) Sensitive determination of heroin based on electrogenerated chemiluminescence of tris(2, 2 -bipyridyl)ruthenium(II) immobilized in zeolite Y modified carbon paste electrode. Analyst 130(4) 534-540. doi 10.1039/b415430d... 

Finally, nanocomposites incorporating electrogenerated PPy have known a growing interest in the last decade, especially those based on carbon nanotubes (CNT). Indeed CNT-PPy hybrids exhibit very high capacitance that makes them promising materials for supercapacitors. Several methods can be envisaged for the obtention of CNT-PPy hybrids electropolymerization on a CNT-array-modified electrode, coelectrodeposition from mixtures of surfactant stabilized aqueous CNT dispersion with the monomer or from mixtures in an ionic liquid layer on the electrode, and alternatively direct electrodeposition of PPy on CNT in a cavity microelectrode. ... 

Allen PM, Hess U, FooteC S, Baizer MM (1982) Electrogenerated bases. IV. Reaction of electrogenerated superoxide with some carbon acids. Synthetic Coirunun 12 123-129 Nugent ST, Baizer MM, Little RD (1982) Electroreductive cyclization. A comparison of the electrochemical and analogous chemical (MIRC) reaction. Tetrahedron Lett 23 1339-1342... 

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