Jacques Perichon

Electrosynthesis of carboxylic acids from organic halides and carbon dioxide

Abstract The electrocarboxylation of a large variety of organic halides is achieved in simple and mild conditions in diaphragm-less cells.

A thermodynamic, structural and kinetic study of the electrochemical lithium intercalation into the xerogel V2O5 · 1.6 H2O in a propylene

Abstract The electrochemical lithium insertion reaction into the vanadium pentoxide xerogel V2O5·.1.6 H2O (noted VXG) in a propylene carbonate solution has been investigated by structural, thermodynamic and kinetic studies. This material, obtained via a sol-gel process, is a lamellar compound whose high anisotropic structure is characterized by the stacking of ribbons in the c direction. The presence of propylene carbonate in the starting material leads to a basal distance of 21.6 A (1 A = 10−10 m). About 1.8 Li+ ions can be accomodated between the ribbons of this lamellar compound at the same energetic level of ~ 3.1 V vs. Li/Li+. Entropy measurements, X-ray diffraction experiments and particle size determinations have given evidence for the existence of two one-phase regions for the composition ranges 0

Electrochemical carboxylation of terminal alkynes catalyzed by nickel complexes: unusual regioselectivity

> 5sx 10−11 cm2 s−1, its low electronic conductivity hinders utilisation of high current densities. Cycling experiments have shown a satisfactory behaviour since for a current density j = 0.05 mA cm−2, about 70% of the initial capacity, ie. 70 Ah/kg, is recovered after the 30th cycle.

ORGANIC ELECTROREDUCTIVE COUPLING REACTIONS USING TRANSITION METAL COMPLEXES AS CATALYSTS

Abstract The electrochemical reduction of the nickel (II) complex Ni(bipy)3(BF4)2 yields an active catalyst for the regioselective functionalization of the 2-position of terminal alkynes with carbon dioxide. A series of α-substituted acrylic acids have been obtained with selectivities of 65–90% and fair overall yields.

Electrochemical behaviour of a silver-exchanged “mordenite”-type zeolite

It is about 20 years since the combination of transition-metal catalysis and electroreduction was shown to be applicable to the coupling of organic molecules. This was followed by a number of fundamental investigations and basic syntheses using various nickel, cobalt, or palladium compounds which can easily be reduced in situ electrochemically to low-valent reactive intermediates. The last decade has been less characterized by reports on new catalytic systems than by the development of new synthetic applications. The aim of this review is to show that the electrochemical processes described here offer valuable advantages in organic synthesis.

The coupling of organic groups by the electrochemical reduction of organic halides: Catalysis by 2,2′-bipyridinenickel complexes

Abstract The electrochemical behaviour of a silver-exchanged “mordenite”-type zeolite (ZO − Ag + ) has been investigated. It has been found that Ag + ions could be electrochemically reduced in aqueous solutions containing various supporting electrolytes according to ZO − Ag + +M′ + + e − →ZO − M′ + +Ag(0) where M′ + represents the cation of the supporting electrolyte; M′ + =Li + , Na + , K + , Cs + , H + , NH 4 + , etc… Such a reaction requires the transfer of silver ions from the zeolite lattice towards the current collector and simultaneously transfer of M′ + cations from external solution into the zeolite lattice. Two kinds of silver metal particles can be formed: crystallites or dendrites on the current collector which can subsequently be reoxidized, and some small particles which can migrate back into the zeolite. The conditions to obtain dispersed silver deposit in zeolite have been discussed and determined. Hence, electrochemical preparation of some zeolite-supported metal catalysts can be anticipated. The diffusion coefficient of silver ions D Ag + has been calculated from a chronoamperometric study performed in 1 M LiClO 4 .

Electrocatalyzed carboxylation of organic halides by a cobalt-salen complex

Abstract The electrochemical reduction of a dilute solution of NiX 2 bipy (bipy = 2,2′-bipyridine) in N -methylpyrrolidone gives the corresponding Ni 0 complex, which undergoes oxidative addition with an excess of an organic halide RX to form RNiX. Decomposition of RNiX gives the dimer R 2 in good yield and nickel(II). The nickel(0) species is regenerated to give an electrocatalytic process. The possible mechanism of these reactions is discussed briefly.

Electrosynthesis of alcohols from organic halides and ketones or aldehydes

The carboxylation of benzylic and allylic chlorides by CO2 in tetrahydrofuran + hexamethylphosphoramide (40% – 60%) is electrocatalyzed by a cobalt Schiff-base complex Co(Salen). The reactions were performed by controlled-potential electrolysis at the RCo (Salen) reduction potential. The yield of the carboxylic acid formation has been calculated.

Mechanism of electrochemical reduction of vanadium oxides

Abstract The electrosynthesis of a wide range of alcohols from organic halides and ketones or aldehydes is achieved under simple and mild conditions in an undivided electrolytic cell using different sacrificial anodes.

Electrochemical cross-coupling between 2-halopyridines and aryl or heteroaryl halides catalysed by nickel-2,2′-bipyridine complexes

Abstract We specify the different electrochemical processes occurring when V2O5 is electrochemically reduced, yielding insertion products with lithium. Under low current density, V2O5 is of a ternary phase of approximate stoichiometry, V2O5Li0.5. During the second step a further reversible insertion of Li+ occurs, yielding V2O5Li without any important modification of the crystalline structure, thus making the reduction reversible. During the two last steps, Li+ incorporation is much more difficult and rapidly causes an important and irreversible modification of the crystalline structure, thus making the reduction irreversible. V2O3, has nearly the same faradaic capacity as V2O5 but, unlike V2O5, it can be hardly be used in batteries since its discharge occurs in a wide potential range.