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Papers by Emmanuel Allard
ChemInform, 2003
) ester, ketone) with C 60 2anion give rise to C 60 (CH 2 -A) 2 adducts (major products) along wi... more ) ester, ketone) with C 60 2anion give rise to C 60 (CH 2 -A) 2 adducts (major products) along with unexpected methanofullerenes C 60 >CH-A and monosubstituted dihydrofullerenes C 60 (H)(CH 2 -A) (minor products). Methanofullerenes are shown to come from side reactions with X 2 CH-A traces.
Organic solar cells based on interpenetrated network of conjugated polymer as donor and fullerene... more Organic solar cells based on interpenetrated network of conjugated polymer as donor and fullerene derivative as acceptor materials have a great potential for improvement of the efficiency. We fabricated a device based on a composite of poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) and [6,6]-phenyl C60 butyric acid methyl ester (PCBM). Surface treatment, insertion of interfacial layers, and improvement of the morphology of the active
Tetrahedron, 2014
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
![Research paper thumbnail of Chemical generation and reactivity of C602−. High-yield and regioselective alkylation of [60, Ih] fullerene](https://attachments.academia-assets.com/39640229/thumbnails/1.jpg)
](Tetrahedron Letters, 1999
Physical Chemistry Chemical Physics, 2002
ABSTRACT Intramolecular photoinduced charge-separation and charge-recombination processes in two ... more ABSTRACT Intramolecular photoinduced charge-separation and charge-recombination processes in two C60-spacer-TTF dyads, in which C60 and TTF (tetrathiafulvalene) are connected through a flexible spacer of different lengths, have been investigated in polar solvents by time-resolved absorption and fluorescence techniques. Weak interaction between the C60-moiety and TTF-moiety in the ground state was suggested by the steady-state absorption spectra; the dyad with the shorter spacer shows slightly stronger interaction than that with the longer spacer. The observed short fluorescence lifetimes of these dyads, compared with that of their precursor fullerene derivative in THF and benzonitrile indicate that the charge separation takes place via the singlet excited state of the C60-moiety, producing the ion pairs (C60˙−-spacer-TTF˙+) as shown from the transient absorption spectra in the 800–1100 nm region. In polar benzonitrile solvent, the ion-pair state with the long flexible chain shows longer lifetime than that with the short chain, suggesting that weaker interaction between C60 and TTF moieties is preferred to the long ion-pair lifetime. These observations were compared with other reported data for C60-TTF dyads.
Organic Letters, 2001
Reactions of chemically generated C 60 2dianion with halo derivatives bearing a second functional... more Reactions of chemically generated C 60 2dianion with halo derivatives bearing a second functional group (halo, ester, ketone) give rise to new organo C 60 derivatives. Thus, the regioselective formation of 1,2-and 1,4-adducts is observed from long-chain halo derivatives, whereas using 1,3-dihaloalkanes leads to 1,2-fused ring C 60 adducts. Such adducts may be used as new synthons in C 60 chemistry, thus leading to new C 60 -based dyads, as exemplified by two examples. 10.
Optics Communications, 2002
We report measurements of the third-order nonlinear optical susceptibilities of a novel dyads of ... more We report measurements of the third-order nonlinear optical susceptibilities of a novel dyads of C 60 -TTF with saturated (ACACA) chemical bonds in solutions were performed using degenerate four wave mixing (DFWM) technique at k ¼ 532 nm in picosecond regime. The third-order nonlinear susceptibilities values, and the corresponding figures of merits are evaluated. The optical power limiting properties of the mentioned compounds are measured using picosecond laser pulses at the same wavelength k ¼ 532 nm. A correlation between the length of the carbon chain (i.e., the increase of the number of saturated (ACACA) bonds and third-order susceptibilities is found.
New Journal of Chemistry, 2003
Functionalized mixed dihydrofullerenes C 60 RH and C 60 RR 0 are easily obtained from reactions b... more Functionalized mixed dihydrofullerenes C 60 RH and C 60 RR 0 are easily obtained from reactions between C 60 2À anion and halo derivatives RX and R 0 X. The key step consists in the selective reaction of the intermediate [C 60 R] À ion, as soon as it is formed, with either CF 3 CO 2 H or R 0 X. This process is made possible thanks to the very fast single electron transfer (SET) reaction between C 60 2À and RX. Functionalized dihydrofullerenes C 60 RH thus prepared are also shown to be very good starting compounds for obtaining various C 60 RR 0 derivatives. y Present address:
Nanoscale, 2012
Herein, we report an easy preparation of azide-coated polystyrenebased nanoparticles (15 nm in di... more Herein, we report an easy preparation of azide-coated polystyrenebased nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength.
Macromolecules, 2012
The convergent synthesis of fluorescent polystyrene core−PAMAM shell nanoparticles in the 15−20 n... more The convergent synthesis of fluorescent polystyrene core−PAMAM shell nanoparticles in the 15−20 nm diameter range is presented using azido-coated nanoparticles (NP N3 ) as a clickable platform. The coupling of the different partners occurs exclusively on the surface of the cross-linked polystyrene matrix owing to its nonswelling properties in water. PAMAM dendrons having an alkyne moiety at their focal point and peripheral carboxylic acid groups were covalently attached to the surface of azido-coated nanoparticles via a CuAAC reaction. Given the high density of azide anchoring groups on the NP surface (about 560 N 3 per NP) and the size of the PAMAM derivative, the grafting of dendrons was not complete, leaving azide units available for further functionalization with an alkyne dansyl derivative. These new dendron-coated nanoparticles, which possess a number of terminal functional groups comparable to the high eighth generation of PAMAM dendrimers, are obtained in a few steps without tedious chromatographic purification. Dendritic shell saturation levels of 70−85% were reached for these dendron-coated nanoparticles. The colloidal stability of the resulting scaffold was governed by the dendritic shell. Particularly, a pH-dependent electrostatic selfassembly process between the ammonium moieties of the cationic surfactant and carboxylate groups of PAMAM can be switched. This straightforward strategy gives access to dendron-coated nanoparticles as valuable building blocks for the construction of functional nanomaterials.
Journal of Polymer Science Part A: Polymer Chemistry, 2012
Journal of Polymer Science Part A: Polymer Chemistry, 2008
The synthesis and pH-sensing properties of fluorescent polymer nanoparticles (NPs) in the 20 nm d... more The synthesis and pH-sensing properties of fluorescent polymer nanoparticles (NPs) in the 20 nm diameter range with a sensitive dye covalently attached to the particle surface and a reference dye entrapped within the particle core are presented. Fluorescein-functionalized NPs were readily obtained by conjugation of fluorescein isothiocyanate (FITC) to amine-coated crosslinked polystyrene-based nanoparticles prepared by microemulsion polymerization followed by postfunctionalization. This all water-based method gave access to stable aqueous suspensions of pH-sensing fluorescent NPs. The encapsulation of the insensitive reference fluorescent dye (1,9-diphenylanthracene, DPA) was then conveniently achieved by soaking leading to dual fluorescent NPs containing about 20 DPA and 55 fluorescein, as deduced from spectroscopic analyses. This core-shell type architecture maximizes the interactions of the sensing dye with the medium while protecting the reference dye. The variations of the ratio of the fluorescence emission intensities of the sensitive dye (fluorescein) to the reference dye (DPA) with pH show that the dual fluorescent NPs act as a ratiometric pH sensor with a measuring range between pH 4 and pH 8. This pH nanosensor was found to be fast, fully reversible, and robust without any leaching of dye over a long period of time. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6206-6213, 2008
![Research paper thumbnail of Liquid-Crystalline Mixed [5 : 1]Hexa-adducts of [60]Fullerene. Preliminary Communication](https://attachments.academia-assets.com/39640245/thumbnails/1.jpg)
](Helvetica Chimica Acta, 2007
A liquid-crystalline mixed [5 : 1]hexa-adduct of [60]fullerene was synthesized by addition of two... more A liquid-crystalline mixed [5 : 1]hexa-adduct of [60]fullerene was synthesized by addition of two different malonate derivatives onto C 60 . The hexa-adduct derivative 2 was prepared by a stepwise synthetic procedure (fullerene ! mono-adduct of C 60 ! hexa-adduct of C 60 ). Cyanobiphenyl and octyloxybiphenyl derivatives were selected as mesogens. The malonate derivatives showed either a monotropic nematic phase or a monotropic smectic A phase, and the hexa-adduct derivative gave rise to an enantiotropic smectic A phase.
Green Chemistry, 2012
The magnetically assisted removal of fatty acids from organic solutions and vegetable oils using ... more The magnetically assisted removal of fatty acids from organic solutions and vegetable oils using iron oxide magnetic nanoparticles (MNPs) was investigated. The effect of contact time and concentration on the adsorption of oleic acid from ethanol-hexane solutions was investigated at room temperature using equilibrium batch experiments. The results showed that the adsorption is rapid (<2 h) and follows a pseudo-second-order model. The adsorption isotherm was found to follow the Langmuir model and the maximum adsorption capacity of oleic acid was determined to be 125 mg g −1 . FTIR analyses of the magnetically separated MNPs demonstrated the covalent binding of the carboxylic group to the particle surface in a bidentate/bridging manner. Thermogravimetric analyses showed that the adsorption capacity of MNPs is very similar for the most common fatty acids in vegetable oils ( palmitic, stearic, oleic and linoleic acids). Desorption of fatty acids was readily achieved upon basic treatment and the regenerated magnetite nanoparticles were found to be recyclable for repeated use. The separation of fatty acids from olive and sunflower oils was investigated without added solvent. MNPs were found to remove up to 85% of the fatty acids in the oil within 2 h with a 10 wt% load at room temperature, without alteration of the pigment composition. † Electronic supplementary information (ESI) available: Additional data, detailed experimental procedure for iron determination, -S10 and Tables S1-S5 as mentioned in the text. See
Advanced Functional Materials, 2007
Cyclam-capped cross-linked nanoparticles (NPc) were prepared in two steps as depicted in Scheme 1... more Cyclam-capped cross-linked nanoparticles (NPc) were prepared in two steps as depicted in Scheme 1. First, halobenzylfunctionalized nanoparticles, noted NPi, were obtained by copolymerization of styrene and vinylbenzylchloride (VBCl) in the presence of divinylbenzene (DVB) as a cross-linking agent
![Research paper thumbnail of Liquid-Crystalline [60]Fullerene-TTF Dyads](https://attachments.academia-assets.com/39587962/thumbnails/1.jpg)
](Organic Letters, 2005
60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic... more 60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic methodology was based on the addition of a malonate derivative to C 60 (Bingel-type reaction). Both the malonate and dyad showed smectic B and A phases. The supramolecular organization within the smectic layers was of the monolayer type for the malonate and of the bilayer type for the fullerene derivative. In the latter case, the supramolecular organization was governed by the C 60 unit.
ChemInform, 2003
) ester, ketone) with C 60 2anion give rise to C 60 (CH 2 -A) 2 adducts (major products) along wi... more ) ester, ketone) with C 60 2anion give rise to C 60 (CH 2 -A) 2 adducts (major products) along with unexpected methanofullerenes C 60 >CH-A and monosubstituted dihydrofullerenes C 60 (H)(CH 2 -A) (minor products). Methanofullerenes are shown to come from side reactions with X 2 CH-A traces.
Organic solar cells based on interpenetrated network of conjugated polymer as donor and fullerene... more Organic solar cells based on interpenetrated network of conjugated polymer as donor and fullerene derivative as acceptor materials have a great potential for improvement of the efficiency. We fabricated a device based on a composite of poly(2-methoxy-5-(2&#39;-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) and [6,6]-phenyl C60 butyric acid methyl ester (PCBM). Surface treatment, insertion of interfacial layers, and improvement of the morphology of the active
Tetrahedron, 2014
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
Tetrahedron Letters, 1999
Physical Chemistry Chemical Physics, 2002
ABSTRACT Intramolecular photoinduced charge-separation and charge-recombination processes in two ... more ABSTRACT Intramolecular photoinduced charge-separation and charge-recombination processes in two C60-spacer-TTF dyads, in which C60 and TTF (tetrathiafulvalene) are connected through a flexible spacer of different lengths, have been investigated in polar solvents by time-resolved absorption and fluorescence techniques. Weak interaction between the C60-moiety and TTF-moiety in the ground state was suggested by the steady-state absorption spectra; the dyad with the shorter spacer shows slightly stronger interaction than that with the longer spacer. The observed short fluorescence lifetimes of these dyads, compared with that of their precursor fullerene derivative in THF and benzonitrile indicate that the charge separation takes place via the singlet excited state of the C60-moiety, producing the ion pairs (C60˙−-spacer-TTF˙+) as shown from the transient absorption spectra in the 800–1100 nm region. In polar benzonitrile solvent, the ion-pair state with the long flexible chain shows longer lifetime than that with the short chain, suggesting that weaker interaction between C60 and TTF moieties is preferred to the long ion-pair lifetime. These observations were compared with other reported data for C60-TTF dyads.
Organic Letters, 2001
Reactions of chemically generated C 60 2dianion with halo derivatives bearing a second functional... more Reactions of chemically generated C 60 2dianion with halo derivatives bearing a second functional group (halo, ester, ketone) give rise to new organo C 60 derivatives. Thus, the regioselective formation of 1,2-and 1,4-adducts is observed from long-chain halo derivatives, whereas using 1,3-dihaloalkanes leads to 1,2-fused ring C 60 adducts. Such adducts may be used as new synthons in C 60 chemistry, thus leading to new C 60 -based dyads, as exemplified by two examples. 10.
Optics Communications, 2002
We report measurements of the third-order nonlinear optical susceptibilities of a novel dyads of ... more We report measurements of the third-order nonlinear optical susceptibilities of a novel dyads of C 60 -TTF with saturated (ACACA) chemical bonds in solutions were performed using degenerate four wave mixing (DFWM) technique at k ¼ 532 nm in picosecond regime. The third-order nonlinear susceptibilities values, and the corresponding figures of merits are evaluated. The optical power limiting properties of the mentioned compounds are measured using picosecond laser pulses at the same wavelength k ¼ 532 nm. A correlation between the length of the carbon chain (i.e., the increase of the number of saturated (ACACA) bonds and third-order susceptibilities is found.
New Journal of Chemistry, 2003
Functionalized mixed dihydrofullerenes C 60 RH and C 60 RR 0 are easily obtained from reactions b... more Functionalized mixed dihydrofullerenes C 60 RH and C 60 RR 0 are easily obtained from reactions between C 60 2À anion and halo derivatives RX and R 0 X. The key step consists in the selective reaction of the intermediate [C 60 R] À ion, as soon as it is formed, with either CF 3 CO 2 H or R 0 X. This process is made possible thanks to the very fast single electron transfer (SET) reaction between C 60 2À and RX. Functionalized dihydrofullerenes C 60 RH thus prepared are also shown to be very good starting compounds for obtaining various C 60 RR 0 derivatives. y Present address:
Nanoscale, 2012
Herein, we report an easy preparation of azide-coated polystyrenebased nanoparticles (15 nm in di... more Herein, we report an easy preparation of azide-coated polystyrenebased nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength.
Macromolecules, 2012
The convergent synthesis of fluorescent polystyrene core−PAMAM shell nanoparticles in the 15−20 n... more The convergent synthesis of fluorescent polystyrene core−PAMAM shell nanoparticles in the 15−20 nm diameter range is presented using azido-coated nanoparticles (NP N3 ) as a clickable platform. The coupling of the different partners occurs exclusively on the surface of the cross-linked polystyrene matrix owing to its nonswelling properties in water. PAMAM dendrons having an alkyne moiety at their focal point and peripheral carboxylic acid groups were covalently attached to the surface of azido-coated nanoparticles via a CuAAC reaction. Given the high density of azide anchoring groups on the NP surface (about 560 N 3 per NP) and the size of the PAMAM derivative, the grafting of dendrons was not complete, leaving azide units available for further functionalization with an alkyne dansyl derivative. These new dendron-coated nanoparticles, which possess a number of terminal functional groups comparable to the high eighth generation of PAMAM dendrimers, are obtained in a few steps without tedious chromatographic purification. Dendritic shell saturation levels of 70−85% were reached for these dendron-coated nanoparticles. The colloidal stability of the resulting scaffold was governed by the dendritic shell. Particularly, a pH-dependent electrostatic selfassembly process between the ammonium moieties of the cationic surfactant and carboxylate groups of PAMAM can be switched. This straightforward strategy gives access to dendron-coated nanoparticles as valuable building blocks for the construction of functional nanomaterials.
Journal of Polymer Science Part A: Polymer Chemistry, 2012
Journal of Polymer Science Part A: Polymer Chemistry, 2008
The synthesis and pH-sensing properties of fluorescent polymer nanoparticles (NPs) in the 20 nm d... more The synthesis and pH-sensing properties of fluorescent polymer nanoparticles (NPs) in the 20 nm diameter range with a sensitive dye covalently attached to the particle surface and a reference dye entrapped within the particle core are presented. Fluorescein-functionalized NPs were readily obtained by conjugation of fluorescein isothiocyanate (FITC) to amine-coated crosslinked polystyrene-based nanoparticles prepared by microemulsion polymerization followed by postfunctionalization. This all water-based method gave access to stable aqueous suspensions of pH-sensing fluorescent NPs. The encapsulation of the insensitive reference fluorescent dye (1,9-diphenylanthracene, DPA) was then conveniently achieved by soaking leading to dual fluorescent NPs containing about 20 DPA and 55 fluorescein, as deduced from spectroscopic analyses. This core-shell type architecture maximizes the interactions of the sensing dye with the medium while protecting the reference dye. The variations of the ratio of the fluorescence emission intensities of the sensitive dye (fluorescein) to the reference dye (DPA) with pH show that the dual fluorescent NPs act as a ratiometric pH sensor with a measuring range between pH 4 and pH 8. This pH nanosensor was found to be fast, fully reversible, and robust without any leaching of dye over a long period of time. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6206-6213, 2008
Helvetica Chimica Acta, 2007
A liquid-crystalline mixed [5 : 1]hexa-adduct of [60]fullerene was synthesized by addition of two... more A liquid-crystalline mixed [5 : 1]hexa-adduct of [60]fullerene was synthesized by addition of two different malonate derivatives onto C 60 . The hexa-adduct derivative 2 was prepared by a stepwise synthetic procedure (fullerene ! mono-adduct of C 60 ! hexa-adduct of C 60 ). Cyanobiphenyl and octyloxybiphenyl derivatives were selected as mesogens. The malonate derivatives showed either a monotropic nematic phase or a monotropic smectic A phase, and the hexa-adduct derivative gave rise to an enantiotropic smectic A phase.
Green Chemistry, 2012
The magnetically assisted removal of fatty acids from organic solutions and vegetable oils using ... more The magnetically assisted removal of fatty acids from organic solutions and vegetable oils using iron oxide magnetic nanoparticles (MNPs) was investigated. The effect of contact time and concentration on the adsorption of oleic acid from ethanol-hexane solutions was investigated at room temperature using equilibrium batch experiments. The results showed that the adsorption is rapid (<2 h) and follows a pseudo-second-order model. The adsorption isotherm was found to follow the Langmuir model and the maximum adsorption capacity of oleic acid was determined to be 125 mg g −1 . FTIR analyses of the magnetically separated MNPs demonstrated the covalent binding of the carboxylic group to the particle surface in a bidentate/bridging manner. Thermogravimetric analyses showed that the adsorption capacity of MNPs is very similar for the most common fatty acids in vegetable oils ( palmitic, stearic, oleic and linoleic acids). Desorption of fatty acids was readily achieved upon basic treatment and the regenerated magnetite nanoparticles were found to be recyclable for repeated use. The separation of fatty acids from olive and sunflower oils was investigated without added solvent. MNPs were found to remove up to 85% of the fatty acids in the oil within 2 h with a 10 wt% load at room temperature, without alteration of the pigment composition. † Electronic supplementary information (ESI) available: Additional data, detailed experimental procedure for iron determination, -S10 and Tables S1-S5 as mentioned in the text. See
Advanced Functional Materials, 2007
Cyclam-capped cross-linked nanoparticles (NPc) were prepared in two steps as depicted in Scheme 1... more Cyclam-capped cross-linked nanoparticles (NPc) were prepared in two steps as depicted in Scheme 1. First, halobenzylfunctionalized nanoparticles, noted NPi, were obtained by copolymerization of styrene and vinylbenzylchloride (VBCl) in the presence of divinylbenzene (DVB) as a cross-linking agent
Organic Letters, 2005
60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic... more 60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic methodology was based on the addition of a malonate derivative to C 60 (Bingel-type reaction). Both the malonate and dyad showed smectic B and A phases. The supramolecular organization within the smectic layers was of the monolayer type for the malonate and of the bilayer type for the fullerene derivative. In the latter case, the supramolecular organization was governed by the C 60 unit.