Benoit Gourdet

Bio: Benoit Gourdet is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: End-group. The author has an hindex of 1, co-authored 1 publications receiving 38 citations.

Extremely regio‐regular poly (3‐alkylthiophene)s from simplified chain‐growth Grignard metathesis polymerisations and the modification of their chain‐ends

Abstract: A simplified route to regio-regular poly(3-alkylthiophene)s (P3AT) with predetermined molecular weights and low molecular weight distributions based on the chain-growth GRIM polymerisation of 2,5-dibromo-3-alkylthiophenes is detailed. It is proposed by way of in-depth 13 C-, 1 H- and two-dimensional NMR characterisations that the resulting P3ATs are quasi-100% regio-regular except for one regio-irregular pair at one chain-end. It is probable that chain-end groups exhibit reduced conjugation with the rest of the polymer. A comparison of the preparation of poly(3-hexylthiophene) and poly(3-butylthiophene) (P3BT) is presented. New methods required for the hydrogenation, formylation and bromomethylation of the chain-ends of P3BT, necessary to overcome its poor solubility and low reactivity, are described.

Direct (Hetero)arylation Polymerization: Simplicity for Conjugated Polymer Synthesis

Abstract: Direct (hetero)arylation polymerization (DHAP) has recently been established as an environmentally benign method for the preparation of conjugated polymers. This synthetic tool features the formation of C–C bonds between halogenated (hetero)arenes and simple (hetero)arenes with active C–H bonds, thereby circumventing the preparation of organometallic derivatives and decreasing the overall production cost of conjugated polymers. Since its inception, selectivity and reactivity of DHAP procedures have been improved tremendously through the careful scrutinity of polymerization outcomes and the fine-tuning of reaction conditions. A broad range of monomers, from simple arenes to complex functionalized heteroarenes, can now be readily polymerized. The successful application of DHAP now leads to nearly defect-free conjugated polymers possessing comparable, if not slightly better, characteristics than their counterparts prepared using classical cross-coupling methods. This comprehensive review describes the mechan...

Chain-Growth Condensation Polymerization for the Synthesis of Well-Defined Condensation Polymers and π-Conjugated Polymers

Abstract: Condensation polymerization is an important method of polymerization that yields not only engineering plastics such as polyamides, polyesters, and polyimides but also π-conjugated polymers, which have recently received considerable attention with the development of the information technology industry. The molecular weight of those polymers is generally difficult to control, and the polydispersity index theoretically approaches 2 at high conversion, which is unlike the behavior of living polymerization. An uncontrolled molecular weight and broad molecular weight distribution do not stem inherently from the reaction type of condensation polymerization, i.e. condensation steps with elimination of a small molecule species but from a polymerization mechanism for step-growth polymerization. Accordingly, if the mechanism of condensation polymerization could be converted from step-growth to chain-growth, living condensation polymerization would be possible. Nature already uses a chain-growth condensation polymerization process to synthesize perfectly monodisperse biopolymers such as polypeptides,1 DNA,2 and RNA.3 For example, in the biosynthesis of polypeptides, the amino group of an aminoacyl-tRNA, monomer, selectively reacts with the terminal ester moiety of polypeptidyl-tRNA in a ribosome to elongate the peptide chain. Even in artificial condensation polymerization of AB monomers, the chain-growth mechanism could be involved in the following two cases. (1) The change of the substituent effect induced by bond formation of the monomer drives the reactivity of the polymer end group to become higher than that of the monomer (Scheme 1A). (2) In condensation polymerization based on a coupling reaction with a transition metal catalyst, the catalyst is intramolecularly transferred to and activates the elongated polymer end group after the coupling reaction of the monomer with the polymer (Scheme * E-mail: yokozt01@kanagawa-u.ac.jp. Tsutomu Yokozawa was born in Chiba in 1957. He received his B.S. (1981), M.S. (1983), and Ph.D. (1987) degrees in Organic Chemistry from Tokyo Institute of Technology under the direction of Professor Nobuo Ishikawa and Professor Takeshi Nakai. In 1985, he had already started an academic career in the Research Laboratory of Resources Utilization, Tokyo Institute of Technology, as a Research Associate, and he was promoted to Assistant Professor in 1988. He joined the Department of Applied Chemistry, Kanagawa University, as a Lecturer in 1991, and he was promoted to Associate Professor in 1993. During 1997-1998, he worked as a visiting scientist at the University of Illinois at Urbana-Champaign with Professor J. S. Moore. He was promoted to Full Professor in 1999. He was also a researcher for PRESTO, JST, during 2001-2005. He received the Award of the Society of Polymer Science, Japan, in 2007. His research interests cover controlled synthesis of polymers, supramolecular chemistry of polymers, as well as synthetic organic chemistry. Chem. Rev. 2009, 109, 5595–5619 5595

High molecular weights, polydispersities, and annealing temperatures in the optimization of bulk-heterojunction photovoltaic cells based on poly(3-hexylthiophene) or poly(3-butylthiophene)

Abstract: A series of poly(3-hexylthiophene)s (P3HTs) and poly(3-butylthiophene)s (P3BTs) with predetermined molecular weights and varying polydispersities are prepared using a simplified Grignard metathesis chain-growth polymerization. Techniques were elaborated to prepare extremely high molecular weight P3HT (number-average molecular weight of around 280 000 g mol–1) with a low polydispersity (< 1.1) without resorting to fractionation. Optimization of the annealing of a series of solar cells based on blends of poly(3-alkylthiophene)s (P3ATs) and [6,6]-phenyl C61 butyric acid methyl ester indicates that the polydispersities, molecular weights, and degrees of conjugation of the P3ATs all have an important impact not only on cell characteristics but also on the most effective annealing temperature required. The results indicate that each cell requires annealing treatments specific to the type of polymer and its molecular weight distribution.

Poly(3-hexylthiophene): synthetic methodologies and properties in bulk heterojunction solar cells

Abstract: Poly(3-hexylthiophene) (P3HT) remains of significant importance as a prototypical benchmark hole conductor material in Organic Photovoltaics (OPVs). In this review we discuss synthetic strategies to P3HT, particularly focusing on those leading to the regioregular form and discussing key physical and morphological properties. Finally, a survey and a brief discussion of P3HT performance in bulk-heterojunction (BHJ) OPVs are also provided.

Mechanistic studies on Ni(dppe)Cl2-catalyzed chain-growth polymerizations: Evidence for rate-determining reductive elimination

Abstract: The mechanisms for Ni(dppe)Cl2-catalyzed chain-growth polymerization of 4-bromo-2,5-bis(hexyloxy)phenylmagnesium chloride and 5-bromo-4-hexylthiophen-2-ylmagnesium chloride were investigated. Rate studies utilizing IR spectroscopy and gas chromatography revealed that both polymerizations exhibit a first-order dependence on the catalyst concentration but a zeroth-order dependence on the monomer concentration. 31P NMR spectroscopic studies of the reactive organometallic intermediates suggest that the resting states are unsymmetrical NiII−biaryl and NiII−bithiophene complexes. In combination, the data implicate reductive elimination as the rate-determining step for both monomers. Additionally, LiCl was found to have no effect on the rate-determining step or molecular weight distribution in the arene polymerization.