Jean-Claude Moutet

Polypyrrole films containing metal complexes: syntheses and applications

Abstract The deliberate modification of electrode surfaces by polymer films containing metal complexes to control the properties of the interface forms a new field that combines coordination chemistry with polymer chemistry and electrochemistry, and which aims at developing new materials for electrocatalysis, electroanalysis and photoelectrochemistry. This review describes the powerful method to prepare polymer coatings on a carrier electrode based on electropolymerization of pyrrole and substituted pyrroles. An overview of prospective applications is given.

Electrochemical coating of a platinum electrode by a poly(pyrrole) film containing the fac-Re (2,2'-bipyridine) (CO)3Cl system. Application to electrocatalytic reduction of CO2

Donnees sur la preparation et le comportement electrochimique des electrodes de Pt recouvertes de films de polypyrrole contenant des complexes de Re(I) avec le bipyridyle

Alkylammonium and pyridinium group-containing polypyrroles, a new class of electronically conducting anion-exchange polymers

Polypyrrole films containing alkylammonium and pyridinium groups have been deposited on platinum and glassy carbon electrode surfaces by oxidative electropolymerization of N-substituted pyrrole monomers. These new functionalized polypyrroles show an improved and potential-independent anion-exchange behaviour, as compared to the regular polypyrrole. They partition ferricyanide ions strongly from organic and aqueous electrolytes and a stable electrochemical reaction of the trapped anions can be observed. Perturbations of the potential of the Fe(CN)3−/4−6 redox ions bound to the polymers are discussed in terms of electrostatic and charge-transfer interactions with ammonium and pyridinium moieties. Organic and inorganic anions can also be trapped effectively in these electronically conducting anion-exchange polymers.

Electrocatalytic epoxidation and oxidation with dioxygen using manganese(III) Schiff-base complexes

Abstract The electrocatalytic properties of different Mn III Schiff-base complexes in acetonitrile solution in the presence of benzoic anhydride, an axial base and dioxygen have been investigated by cyclic voltammetry. Bulk electrolysis in the presence of cyclooctene yields cyclooctene oxide and shows that the best catalyst complexes (in terms of current efficiency and turnover) are based on ligands containing an ethano (Salen complexes) or a 1,2-cyclohexylidene (Salchx complexes) bridging unit and 5,5′-dichloro substituents. The effect of axial base such as pyridine, collidine, 1- and 2-methylimidazole is shown. The use of the latter base gave the best results for cycloctene epoxidation. Some investigation on tetraline and triphenylphosphine oxidation are also reported.

Poly(pyrrole-manganese porphyrin): A catalytic electrode material as a model system for olefin epoxidation and drug metabolism with molecular oxygen

Abstract The oxidative electropolymerization of three pyrrole-substituted manganese tetraphenylporphyrins can be used to coat Pt or C electrodes with polymeric films able to catalyse the epoxidation of cyclo-octene and stilbene with molecular oxygen. Cross-linked polymers prepared from monomers containing two or three pyrrole groups, and thus having a better polymerizability, present a lower activity than the polymeric films synthesized from the monomer containing only one pyrrole moiety. Confinement of the catalyst on the electrode surface markedly improves its stability compared with that of homogeneous electrocatalytic systems. This catalytic electrode material has been successfully applied to the preparation of oxidized metabolites of a drug.

Viologen-based redox-switchable anion-binding receptors

A series of viologen-based receptors have been synthesized and their anion-binding properties have been investigated by-NMR, UV-visible spectroscopy, electrochemistry and X-ray diffraction analyses. Linking two positively charged viologens through a propyl chain promotes a remarkable chelate-like binding of chlorides revealed by 1H-NMR spectroscopy. Of all the anionic species investigated, only fluoride is detectable by the naked eye and by electrochemical methods. The reduction-triggered formation of a π-dimer from two viologen-based cation radicals was also investigated by electrochemical and spectroelectrochemical methods and by theoretical calculations.

Complexation and electrochemical sensing of anions by amide-substituted ferrocenyl ligands

New amide-containing ferrocenyl ligands, L1–5, were prepared and the voltammetric and 1H NMR investigations of anion binding were carried out in organic media. The electrochemical recognition ability of L1–5 towards F−, HSO4−, H2PO4− and ATP2− is based on the synergy between H-bonding to amide protons in anion complexation to reduced, neutral ligands and ion-pairing interactions developed with the oxidized, cationic form of the ligands. The strength of the anion–ligand interactions depends on the number of ferrocene centers and amide groups in the receptor, and on the accessibility of the binding sites. Clear two-wave cyclic voltammetry features allowed the amperometric titration of H2PO4− and ATP2− by ligands L4 and L5 built from a cyclotriveratrylene structural unit, and containing a combination of three ferrocene centers with three (L4) or six (L5) amide groups.

(Ferrocenylmethyl)trimethylammonium cation: a very simple probe for the electro-chemical sensing of dihydrogen phosphate and ATP anionsElectronic supplementary information (ESI) available: cyclic voltammograms of 1 in the presence of increasing amounts of ATP2– or HSO4–. See http://www.rsc.org/suppdata/nj/b1/b107713a/

By virtue of strong ion-pairing interactions that are reinforced following its oxidation to the ferrocinium form, (ferrocenylmethyl)trimethylammonium cation is able to electrochemically sense dihydrogen phosphate and ATP anions in organic electrolytes; clear two-wave voltammetry features allow their amperometric titration by this very simple derivative of ferrocene.

Soluble heterometallic coordination polymers based on a bis-terpyridine-functionalized dioxocyclam ligand.

Soluble homo- and heterometallic coordination polymers containing transition metal cations (Cu(2+), Fe(2+), Co(2+), and Ni(2+) ions) were prepared in a two-step procedure using a polytopic bis(terpyridine)dioxocyclam ligand 1H(2) (dioxocyclam = 1,4,8,11-tetraazacyclotetradecane-5,7-dione). These supramolecular systems incorporate two different metal complexes, the metal cations being located both between two terpyridine units and in the macrocyclic framework. The characterization of these soluble architectures was investigated by cyclic voltammetry, mass spectrometry, viscosimetry, and UV-vis absorption and electron paramagnetic resonance (EPR) spectroscopies. Our results clearly indicate the formation of well-organized heterometallic polymers in which two different metal ions alternate in the self-assembled structure. These investigations furthermore brought to light an original acid-controlled disassembling process of the homometallic copper(II) polymer into dinuclear complexes.

Anion recognition and redox sensing by a metalloporphyrin–ferrocene–alkylammonium conjugate

The synthesis and characterization of a novel redox molecular receptor is reported. This chemosensor is structured on a ferrocene fragment whose cyclopentadienyl moieties have been connected to distinct and complementary zinc porphyrin and alkylammonium binding sites, enabling multipoint recognition and detection of anionic species. Cumulative effects of multiple anchoring points on this ammonium–ferrocene–metalloporphyrin chemosensor allowed the unprecedented ferrocene-based voltammetric sensing of halide anions.