References of "Lecomte, Philippe"
     in
Bookmark and Share    
See detailMacromolecular engineering of aliphatic polyesters by click chemistry
Lecomte, Philippe ULg

Scientific conference (2009, September 10)

Detailed reference viewed: 23 (9 ULg)
Full Text
See detailNew developments in the functionalization of aliphatic polyesters by "click" copper-catalyzed azide-alkyne cycloaddition
Lecomte, Philippe ULg; Riva, Raphaël ULg; Schmeits, Stephanie ULg et al

Conference (2009, June 03)

Nowadays, biodegradable and biocompatible aliphatic polyesters are widely used as environmentally friendly thermoplastics and biomaterials. Nevertheless, the absence of any pendant functional group is a ... [more ▼]

Nowadays, biodegradable and biocompatible aliphatic polyesters are widely used as environmentally friendly thermoplastics and biomaterials. Nevertheless, the absence of any pendant functional group is a severe limitation for the development of novel applications. Our strategy aiming at functionalizing aliphatic polyesters relies on the “click” copper-catalyzed cycloaddition (CuAAC) of alkynes duly substituted by functional groups or even chains onto PCL bearing pendant azides. The aliphatic polyesters bearing pendant azides have been very efficiently synthesized by a straightforward approach, which relies on the ring-opening copolymerization of αClεCL (or γBrεCL) and εCL (or lactide) followed by reaction with sodium azide to convert pendant chlorides or bromides into azides. The alternative reported by Emrick et al. is based on the CuAAC reaction of azides substituted by any functional group onto copolyesters of poly(ε-caprolactone) bearing pendant alkynes. Interestingly enough, Emrick et al. carried out the CuAAc reaction in water at 80°C. Unfortunately, it turned out, at least in our hands, that these conditions can not be extended to the derivatization of more sensitive aliphatic polyesters because degradation was then unavoidable. Nevertheless, we found out that degradation can be minimized whenever the CuAAC reaction is carried out in an organic solvent at lower temperature. Typically, the CuAAC reaction was carried out in DMF or THF at 35°C. Recently, it was shown that supercritical carbon dioxide can be used as a more environmentally friendly solvent than DMF or THF. The contamination by catalytic residues of aliphatic polyesters functionalized by the CuAAC reaction is a severe limitation in view of future applications, especially in the biomedical field. In the last part of this talk, a special attention will be paid on our current efforts to get rid of copper residues. [less ▲]

Detailed reference viewed: 62 (22 ULg)
Full Text
See detailFunctionalization of aliphatic polyesters by “click chemistry” in supercritical carbon dioxide
Grignard, Bruno ULg; Schmeits, Stephanie ULg; Riva, Raphaël ULg et al

Poster (2009, May 14)

The combination of ring-opening polymerization of lactones and “click” copper-catalyzed Huisgen’s [3+2] cycloaddition is known to be a very efficient strategy for the functionalization of poly(ε ... [more ▼]

The combination of ring-opening polymerization of lactones and “click” copper-catalyzed Huisgen’s [3+2] cycloaddition is known to be a very efficient strategy for the functionalization of poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA). Whenever the “click” reaction occurs in an organic solvent (THF or DMF), at relatively low temperature (35°C) and within short reaction time (2 hours), no significant degradation of polyester chains is detected. This strategy was implemented in previous works to graft alkynes substituted by different functional groups, such as hydroxyl, tertiary amines, acrylates or ammonium salts onto azide-functionalized PCL. Moreover, this approach was previously extended to the synthesis of grafted copolymers, either by the grafting of omega-alkyne-PEO onto azide-functionalized aliphatic PLA or PCL (“grafting onto” technique) either by grafting of an ATRP initiator followed by the polymerization of vinyl monomers, such as styrene (“grafting from” technique). These functionalized aliphatic polyesters are promising materials for the development of new biomedical devices. In this work, novel conditions were implemented for the “click” reaction in order to avoid the use of organic solvents and to limit the amount of catalyst remnants in functionalized aliphatic polyesters. Toward this end, if was found that the functionalization by “click” chemistry can be efficiently carried out in supercritical carbon dioxide rather than in THF or DMF. For that sake, it turned out necessary to synthesize a perfluorinated polyamine in order to solubilize the catalyst in supercritical carbon dioxide. Aliphatic polyesters are not soluble in supercritical carbon dioxide. Nevertheless, even under heterogeneous conditions, the functionalization of aliphatic polyesters by “click” chemistry is quantitative. Interestingly enough, no degradation was observed. Last but not least, the copper catalyst was easily removed by supercritical fluid extraction leading to a very low content of residual copper in the final copolyester. [less ▲]

Detailed reference viewed: 136 (16 ULg)
See detailAn analysis of the role of cyclin dependant kinase inhibitor 1B (CDKN1B) gene mutations in 86 families with familial isolated pituitary adenomas (FIPA)
Tichomirova, M. A.; Daly, Adrian ULg; Pujol, Julien ULg et al

in The Endocrine Society's 91st Annual Meeting : 10-13 juin 2009, Washington (2009)

Detailed reference viewed: 29 (7 ULg)
Full Text
See detailMetal enolates in polymer science and technology
Lecomte, Philippe ULg; Jérôme, Robert ULg

in Zabicky, Jacob (Ed.) The Chemistry of Metal Enolates (2009)

Detailed reference viewed: 14 (4 ULg)
Full Text
See detailRecent advances in the synthesis of aliphatic polyesters by “click” chemistry
Riva, Raphaël ULg; Jérôme, Christine ULg; Jérôme, Robert ULg et al

Conference (2008, September 11)

Since the discovery of Sharpless and Meldal, the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is more and more popular in the field of macromolecular engineering owing to its robustness, its ... [more ▼]

Since the discovery of Sharpless and Meldal, the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is more and more popular in the field of macromolecular engineering owing to its robustness, its high tolerance to a wide range of functional groups without any need of protecting groups and the absence of side-products. This reaction is known to be a very efficient “click” reaction as defined by Sharpless. The chemical modification of aliphatic polyesters remains, at the time being, a very difficult task to achieve because of the very limited number of efficient chemical reactions, which can be implemented in the absence of chain degradation. The main purpose of this contribution is to report on the most recent advances on the use of CuAAC to derivatize aliphatic polyesters (Scheme 1). Interestingly enough, it was recently shown that CuAAC carried out onto aliphatic polyesters attached with either azides or alkynes is very efficient under mild conditions, which limit undesirable degradation. Several functional groups were grafted onto aliphatic polyesters by CuAAC without using any protection/deprotection reactions. The CuAAC is also very efficient to prepare aliphatic polyesters with various architectures as highlighted by the synthesis of graft copolymers, star-shaped copolymers and networks. This “click” chemistry has been combined with other polymerization mechanism such as ATRP in order to extend further the range of available polymers. [less ▲]

Detailed reference viewed: 37 (11 ULg)
Full Text
See detailMacromolecular engineering of aliphatic polyesters by ring-opening polymerization
Lecomte, Philippe ULg; Jérôme, Christine ULg; Jérôme, Robert ULg

Conference (2008, September 09)

During the past few years, a steadily increasing attention was paid to the synthesis of biodegradable and biocompatible aliphatic polyesters because of potential applications as biomaterials or as ... [more ▼]

During the past few years, a steadily increasing attention was paid to the synthesis of biodegradable and biocompatible aliphatic polyesters because of potential applications as biomaterials or as environmentally friendly thermoplastics. The first purpose of this work is to show that the modification of these aliphatic polyesters by pendant functional groups is an efficient tool to tailor the main properties, including biodegradation rate, bioadhesion, hydrophilicity, degree of crystallinity. The strategies implemented for the synthesis of aliphatic polyesters bearing pendant functional groups rely on the synthesis of g-substituted e-caprolactones followed by their ring-opening polymerization and on the chemical modification of duly functionalized aliphatic polyesters.The second part of the lecture will be dedicated to some recent examples dealing with the use of functional caprolactones to prepare various architectures such as star-shaped copolymers, graft copolymers, macrocycles and networks. [less ▲]

Detailed reference viewed: 24 (8 ULg)
Full Text
Peer Reviewed
See detailMacromolecular engineering of biodegradable polyesters by ring-opening polymerization and 'Click' chemistry
Lecomte, Philippe ULg; Riva, Raphaël ULg; Jérôme, Christine ULg et al

in Macromolecular Rapid Communications (2008), 29(12-13), 982-997

Biodegradability makes aliphatic polyesters valuable candidates for biomaterials and environmentally friendly thermoplastics. Nevertheless, their chemical modification, which is mandatory for a series of ... [more ▼]

Biodegradability makes aliphatic polyesters valuable candidates for biomaterials and environmentally friendly thermoplastics. Nevertheless, their chemical modification, which is mandatory for a series of potential applications, is usually a problem because it must be carried out under very mild conditions in order to prevent degradation by hydrolysis and/or transesterification from occurring. In this review, the copper(i) -catalyzed azide-alkyne cycloaddition, which is a click reaction, is shown to be very efficient to bypass these problems and to tailor the macromolecular architecture and functionality of those polyesters without facing undesired degradation reactions. [less ▲]

Detailed reference viewed: 53 (23 ULg)
Full Text
Peer Reviewed
See detailRecent advances in the synthesis of aliphatic polyesters by ring-opening polymerization
Jérôme, Christine ULg; Lecomte, Philippe ULg

in Advanced Drug Delivery Reviews (2008), 60(9), 1056-1076

Advanced drug delivery systems rely on the availability of biocompatible materials. Moreover, biodegradability is highly desirable in the design of those systems. Consequently, aliphatic polyesters appear ... [more ▼]

Advanced drug delivery systems rely on the availability of biocompatible materials. Moreover, biodegradability is highly desirable in the design of those systems. Consequently, aliphatic polyesters appear as a class of promising materials since they combine both properties. Nevertheless, their use in practical biomedical systems relies on clinical approval which not only depends on the material itself but also on its reproducible synthesis with the absence of residual toxics. The first sections of this review aim at reporting on the evolution of the initiators/catalytic systems and of the synthesis conditions (particularly the use of supercritical CO2 as polymerization medium) in order to produce aliphatic polyesters with controlled macromolecular parameters by still "greener" ways. In addition, the further development of delivery systems also depends on the synthesis of materials exhibiting novel properties, such as amphiphilicity or pH-sensitivity that are emerging from the active research in macromolecular engineering. Functionalizing aliphatic polyesters is quite tedious due to their sensitivity towards hydrolytic degradation. The last section of this review is discussing several strategies to obtain functional (co)polyesters of various architectures providing them with novel properties. [less ▲]

Detailed reference viewed: 38 (7 ULg)
See detailNew developments on the macromolecular engineering of ring-shaped aliphatic polyesters
Lecomte, Philippe ULg; Li, Haiying; Jérôme, Robert ULg

Scientific conference (2008, May 30)

Detailed reference viewed: 8 (2 ULg)
Full Text
Peer Reviewed
See detailContribution of "click chemistry" to the synthesis of antimicrobial aliphatic copolyester
Riva, Raphaël ULg; Lussis, Perrine ULg; Lenoir, Sandrine ULg et al

in Polymer (2008), 49(8), 2023-2028

A straightforward strategy is proposed to impart antimicrobial properties to biodegradable poly(oxepan-2-one) (poly(epsilon-caprolactone) or PCL), which is based on the grafting of pendant ammonium salts ... [more ▼]

A straightforward strategy is proposed to impart antimicrobial properties to biodegradable poly(oxepan-2-one) (poly(epsilon-caprolactone) or PCL), which is based on the grafting of pendant ammonium salts by "click" chemistry. First, statistical copolymerization of 3-chlorooxepan-2-one (alpha-chloro-epsilon-caprolactone or alpha Cl epsilon CL) with oxepan-2-one (epsilon-caprolactone or epsilon CL) was initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP). In a second step, pendant chlorides were converted into azides by reaction with sodium azide (NaN3). Finally, quaternary ammonium containing alkynes were quantitatively added to the pendant azide groups of PCL by the copper-catalyzed Huisgen's 1,3-dipolar cycloaddition, which is a typical "click" reaction. An alternative two-step strategy based on the cycloaddition of the amine containing alkyne onto the pendant azides, followed by quaternization turned out to be less efficient. The antimicrobial activity was analyzed by the "shaking flask method" in the presence of Escherichia coli [less ▲]

Detailed reference viewed: 86 (17 ULg)
Full Text
See detailSynthesis of novel functional aliphatic polyesters by association of ring-opening polymerization and click chemistry
Lecomte, Philippe ULg; Schmeits, Stephanie ULg; Riva, Raphaël ULg et al

Conference (2008, April 09)

Nowadays, biodegradable and biocompatible aliphatic polyesters are widely used as environmentally friendly thermoplastics and biomaterials. Nevertheless, the absence of any functional group along the ... [more ▼]

Nowadays, biodegradable and biocompatible aliphatic polyesters are widely used as environmentally friendly thermoplastics and biomaterials. Nevertheless, the absence of any functional group along the chain is a severe limitation for the development of new applications. Very recently, it was reported by Emrick et al. and by us that copper(I)-mediated 1,3-dipolar Huisgen's cycloaddition of alkynes and azides, the most widely used “click” reaction in the frame of macromolecular engineering, is very efficient to derivatize aliphatic polyesters. Due to the tolerance for many functional groups, cumbersome protection and deprotection steps are not needed. One main advantage of copper(I)-mediated Huisgen's cycloaddition compared to other reactions previously used to derivatize aliphatic polyesters relies on the mildness of the experimental conditions, which results in limited degradation. Our most recent results dealing with the combination of “click” chemistry and ring-opening polymerization towards functional PCL and PLA, networks, graft and hyperbranched copolymers will be highlighted. [less ▲]

Detailed reference viewed: 44 (9 ULg)
Full Text
Peer Reviewed
See detailAmphiphilic sun-shaped polymers by grafting macrocyclic copolyesters with PEO
Li, Haiying; Jérôme, Robert ULg; Lecomte, Philippe ULg

in Macromolecules (2008), 41(3), 650-654

An amphiphilic sun-shaped copolymer was successfully prepared by esterification of carboxylic acid terminated PEO with the pendent hydroxyl groups of high molecular weight (M-n = 28 000) cyclic PCL. The ... [more ▼]

An amphiphilic sun-shaped copolymer was successfully prepared by esterification of carboxylic acid terminated PEO with the pendent hydroxyl groups of high molecular weight (M-n = 28 000) cyclic PCL. The cyclic structure of the copolyester originally resulted from the polymerization initiation by a cyclic tin dialkoxide and was ultimately stabilized by the intramolecular cross-linking of a few unsaturated groups. [less ▲]

Detailed reference viewed: 27 (12 ULg)
Full Text
Peer Reviewed
See detailPH-responsive biodegradable amphiphilic networks
Zednik, Jiri; Riva, Raphaël ULg; Lussis, Perrine ULg et al

in Polymer (2008), 49(3), 697-702

Copper-mediated azide - alkyne Huisgen's 1,3-dipolar cycloaddition is a "click" reaction that was successfully used to prepare pH-responsive, amphiphilic and biodegradable networks. Indeed, this reaction ... [more ▼]

Copper-mediated azide - alkyne Huisgen's 1,3-dipolar cycloaddition is a "click" reaction that was successfully used to prepare pH-responsive, amphiphilic and biodegradable networks. Indeed, this reaction proved to be very efficient in the "one pot" grafting of amino alkyne onto azide containing poly(epsilon-caprolactone) and the cross-linking of these chains by alpha,omega-dialkynyl poly(ethylene oxide). The pH-controlled release of guests hosted during the cross-linking step was illustrated with an entrapped model dye. [less ▲]

Detailed reference viewed: 36 (12 ULg)