Didier Delabouglise

Chiral metals: Amino acid substituted conducting polypyrroles

Abstract Chiral amino acid groups are substituted on the 3 position of pyrrole. These functionalized monomers are electropolymerized, the high conductivity obtained for the polymers confirming the existence of long conjugated chains. The circular dichroism spectra of these polypyrroles exhibit a large positive Cotton effect, centered on the absorption band associated with the intrachain bipolaronic transition. These results reveal that the conjugated chains of conducting polypyrroles themselves have become chiral, because of an induction effect originating from the chiral substituents.

Stabilization of the conductivity of poly(3-methylthiophene) by triflimide anions

Abstract A new doping anion is proposed for electronically conducting polymers. Poly(3-methylthiophene) doped with bis(trifluoromethanesulfonyl)imide anions exhibits a high conductivity (460 S cm −1 ) and a remarkable stability of the conducting state in ambient atmosphere (7% loss after 40 days). These effects are explained by the highly delocalized charge of this anion, resulting in very weak basicity and lower chemical reactivity.

Dihydrophenazine derivatives for overcharge protection of rechargeable lithium batteries

Abstract Two dihydrophenazine derivatives bearing either 2-hydroxypropyl or ethyl substituents on both N atoms, have been tested in liquid and polymer electrolyte lithium cells. Only the first one bearing 2-hydroxypropyl substituents induced a levelling of the overcharge potential. The fixed potential corresponded to either of its redox systems according to the current density and the internal resistance of the unit cells. At present the possible determining role of the hydroxyl groups is a drawback owing to its reactivity on lithium metal.

Enantioselective chiral poly(thiophenes)

Chiral poly(thiophenes) have been synthesized by electropolymerization; they exhibit high specific rotation, stability, and conductivity and can stereoselectively recognize chiral anions used as doping agents during voltammetric cycles.

Modification of the structure and electrochemical properties of poly(thiophene) by ether groups

Poly[3-(3,6-dioxaheptyl)thiophene] has been synthesised by electropolymerisation; this highly conducting electroactive polymer exhibits specific interactions with lithium cations.

Biotin grafting on boron-doped diamond.

Grafting of biotin on top of a polycrystalline boron-doped diamond layer was achieved by surface oxidation followed by an esterification reaction and revealed by fluorescently labelled streptavidin.

Cation recognition properties of polypyrrole 3-substituted by azacrown ethers

The synthesis of new functionalized conducting polypyrroles bearing azacrown ethers at C-3 is described; these show selective cation binding on voltammetric cycling in organic media.

Influence of the molecular structure on the refractive index of semiconducting di‐β‐alkylated sexithiophenes

The optical absorption of thin solid films of dialkylated sexithiophene derivatives (2A6T) has been measured at incident energies below the fundamental absorption edge, where these semiconducting organic materials are transparent. The absorption spectra present interference patterns that have been used for determining their refractive index n. A value of 1.904 was measured on unsubstituted sexithiophene. Alkyl substitution leads to a decrease of n, which is more pronounced as the alkyl chain length increases. This behavior is attributed to the corresponding decrease of the density of the material. Our data are compared to other experimental determinations of the optical parameters of thiophene oligomers and polymers published to date.

Control of the interface properties of conducting polypyrrole

Abstract Chemical modification of polypyrrole by 3-substitution of the monomer results in different kinds of new interface properties for the corresponding material. Alkylation allows a marked increase in the hydrophobicity and its regulation by the substituent length. Polyether chains increase the reversibility of the polymer redox system in organic electrolyte, and thus the power capability and the long-term stability of polypyrrole as an electrode material for batteries. Substituted carboxylic groups give rise to a linear pH-dependence of the formal redox potential of polypyrrole in acidic media.

Polyethyleneoxide-dihydrophenazine block copolymer as a cathode material for lithium-polymer batteries

Abstract Polycondensation of N,N′-bis-(2-hydroxypropyl)-dihydrophenazine with end tosylated short polyethyleneoxide chains gave rise to a new block copolymer alternating electroactive molecular units with cation solvating segments. Typical voltammetric waves of the dihydrophenazine units were obtained from organic liquid solution of this copolymer. Solid state electrochemistry in a lithium–polymer cell afforded promising battery performances.