You will find below the publication list of our pole.
For the publication list of each pole member, please see his/her personal webpage.
2002 |
Synthesis and properties of water-soluble gold colloids covalently derivatized with neutral polymer monolayers Article de journal C Mangeney; F Ferrage; I Aujard; V Artzner; L Jullien; O Ouari; E Djouhar Rékai; A Laschewsky; I Vikholm; J W Sadowski Journal of the American Chemical Society, 124 (20), p. 5811–5821, 2002. @article{Mangeney:2002, title = {Synthesis and properties of water-soluble gold colloids covalently derivatized with neutral polymer monolayers}, author = {C Mangeney and F Ferrage and I Aujard and V Artzner and L Jullien and O Ouari and E Djouhar R\'{e}kai and A Laschewsky and I Vikholm and J W Sadowski}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037157185&doi=10.1021%2fja010796h&partnerID=40&md5=0866a4217a986ce8c43d1a84df5645a0}, doi = {10.1021/ja010796h}, year = {2002}, date = {2002-01-01}, journal = {Journal of the American Chemical Society}, volume = {124}, number = {20}, pages = {5811--5821}, abstract = {Citrate-capped gold nanoparticles as well as planar gold surfaces can be efficiently grafted with a covalently attached polymer monolayer a few nanometers thick, by simple contact of the metal surface with dilute aqueous solutions of hydrophilic polymers that are end-capped with disulfide moieties, as shown by UV/vis absorption, dynamic light scattering, and surface plasmon resonance studies. The hydrophilic polymer-coated gold colloids can be freeze-dried and stored as powders that can be subsequently dissolved to yield stable aqueous dispersions, even at very large concentrations. They allow for applying filtrations, gel permeation chromatography, or centrifugation. They do not suffer from undesirable nonspecific adsorption of proteins while allowing the diffusion of small species within the hydrogel surface coating. In addition, specific properties of the original hydrophilic polymers are retained such as a lower critical solution temperature. The latter feature could be useful to enhance optical responses of functionalized gold surfaces toward interaction with various substrates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Citrate-capped gold nanoparticles as well as planar gold surfaces can be efficiently grafted with a covalently attached polymer monolayer a few nanometers thick, by simple contact of the metal surface with dilute aqueous solutions of hydrophilic polymers that are end-capped with disulfide moieties, as shown by UV/vis absorption, dynamic light scattering, and surface plasmon resonance studies. The hydrophilic polymer-coated gold colloids can be freeze-dried and stored as powders that can be subsequently dissolved to yield stable aqueous dispersions, even at very large concentrations. They allow for applying filtrations, gel permeation chromatography, or centrifugation. They do not suffer from undesirable nonspecific adsorption of proteins while allowing the diffusion of small species within the hydrogel surface coating. In addition, specific properties of the original hydrophilic polymers are retained such as a lower critical solution temperature. The latter feature could be useful to enhance optical responses of functionalized gold surfaces toward interaction with various substrates. |
UV-vis subpicosecond spectroscopy of 4-(9-anthryl)-N,N′-dimethylaniline in polar and nonpolar solvents: A two-dimensional view of the photodynamics Article de journal M M Martin; P Plaza; P Changenet-Barret; A Siemiarczuk Journal of Physical Chemistry A, 106 (10), p. 2351–2358, 2002. @article{Martin:2002, title = {UV-vis subpicosecond spectroscopy of 4-(9-anthryl)-N,N′-dimethylaniline in polar and nonpolar solvents: A two-dimensional view of the photodynamics}, author = {M M Martin and P Plaza and P Changenet-Barret and A Siemiarczuk}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037075488&doi=10.1021%2fjp013107x&partnerID=40&md5=0302b1415347c0cd27d9e53261d1a8ca}, doi = {10.1021/jp013107x}, year = {2002}, date = {2002-01-01}, journal = {Journal of Physical Chemistry A}, volume = {106}, number = {10}, pages = {2351--2358}, abstract = {Transient absorption and gain spectra are reported for 4-(9-anthryl)-N,N′-dimethylaniline (ADMA) in polar and nonpolar solvents in the 330-780 nm wavelength range after excitation with a 500-fs laser at 370 nm. In acetonitrile, the initial transient spectra can be interpreted by the superposition of the dimethylaniline cation radical and the anthracene anion radical absorption bands, resulting from the well-known ultrafast photoinduced charge separation. In benzonitrile, similar transient spectra are reached 20-30 ps after excitation. In this solvent, as well as in alcohols, tetrahydrofuran and cyclohexane, the initial UV and visible absorption bands exhibit the spectral characteristics of the locally excited (LE) state. With increasing time, while these bands decay, the signature of the charge-transfer (CT) state appears and one observes a red shift of the region of minimum differential absorption, where gain is expected. These changes occur at a solvent-dependent rate, except in acetonitrile in which the spectra show little evolution because of our limited time resolution. Discrepancies with previously published models for ADMA photodynamics are discussed. In polar solvents except acetonitrile, a quasi-barrierless or slightly activated electron transfer is proposed to explain the long-time decay of the UV absorption band attributed to the LE state. On the other hand, inertial internal torsion around the bond linking the aniline and anthracene moieties in the LE state followed by solvation-induced charge separation similar to that in bianthryl is proposed to explain differences between acetonitrile and benzonitrile or other solvents in the UV range. A two-dimensional picture in which both internal torsion and solvation dynamics determine the excited-state reaction path is discussed, taking into account the initial proposal made by Mataga's group. In cyclohexane, in which solvation effects are not expected, the spectral changes in the picosecond time range are attributed to geometrical relaxation within the S1 state.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Transient absorption and gain spectra are reported for 4-(9-anthryl)-N,N′-dimethylaniline (ADMA) in polar and nonpolar solvents in the 330-780 nm wavelength range after excitation with a 500-fs laser at 370 nm. In acetonitrile, the initial transient spectra can be interpreted by the superposition of the dimethylaniline cation radical and the anthracene anion radical absorption bands, resulting from the well-known ultrafast photoinduced charge separation. In benzonitrile, similar transient spectra are reached 20-30 ps after excitation. In this solvent, as well as in alcohols, tetrahydrofuran and cyclohexane, the initial UV and visible absorption bands exhibit the spectral characteristics of the locally excited (LE) state. With increasing time, while these bands decay, the signature of the charge-transfer (CT) state appears and one observes a red shift of the region of minimum differential absorption, where gain is expected. These changes occur at a solvent-dependent rate, except in acetonitrile in which the spectra show little evolution because of our limited time resolution. Discrepancies with previously published models for ADMA photodynamics are discussed. In polar solvents except acetonitrile, a quasi-barrierless or slightly activated electron transfer is proposed to explain the long-time decay of the UV absorption band attributed to the LE state. On the other hand, inertial internal torsion around the bond linking the aniline and anthracene moieties in the LE state followed by solvation-induced charge separation similar to that in bianthryl is proposed to explain differences between acetonitrile and benzonitrile or other solvents in the UV range. A two-dimensional picture in which both internal torsion and solvation dynamics determine the excited-state reaction path is discussed, taking into account the initial proposal made by Mataga's group. In cyclohexane, in which solvation effects are not expected, the spectral changes in the picosecond time range are attributed to geometrical relaxation within the S1 state. |
2001 |
A hyperpolar, multichromophoric cyclodextrin derivative: Synthesis, and linear and nonlinear optical properties Article de journal E D Rekaï; J -B Baudin; L Jullien; I Ledoux; J Zyss; M Blanchard-Desce Chemistry - A European Journal, 7 (20), p. 4395–4402, 2001. @article{Rekai:2001, title = {A hyperpolar, multichromophoric cyclodextrin derivative: Synthesis, and linear and nonlinear optical properties}, author = {E D Reka\"{i} and J -B Baudin and L Jullien and I Ledoux and J Zyss and M Blanchard-Desce}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035887434&doi=10.1002%2f1521-3765%2820011015%297%3a20%3c4395%3a%3aAID-CHEM4395%3e3.0.CO%3b2-W&partnerID=40&md5=a7139d4eee973c3a274eacb7e3bc5041}, doi = {10.1002/1521-3765(20011015)7:20<4395::AID-CHEM4395>3.0.CO;2-W}, year = {2001}, date = {2001-01-01}, journal = {Chemistry - A European Journal}, volume = {7}, number = {20}, pages = {4395--4402}, abstract = {A chiral, highly polar, multichromophoric supermolecule has been designed by gathering seven push-pull chromophores onto a β-cyclodextrin assembling unit through covalent flexible linkers. The photophysical and nonlinear optical properties of this mutichromophoric conical bundle were investigated and compared with those of the monomeric chromophore. The strongly absorbing multichromophoric system combines interesting features: it has a high molecular first-order hyperpolarisability and a very large dipolar moment (μ=38 D) which reveal a self-arrangement of the dipolar chromophores within the supermolecule. The confinement of the push-pull chromophores within the nanoscopic bundle affects their optical properties and promotes interactions: The multichromophoric supermolecule is hypochromically and hypsochromically shifted with respect to its monomeric analogue. In addition, the close proximity promotes excitonic coupling, as well as excimer formation phenomena.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A chiral, highly polar, multichromophoric supermolecule has been designed by gathering seven push-pull chromophores onto a β-cyclodextrin assembling unit through covalent flexible linkers. The photophysical and nonlinear optical properties of this mutichromophoric conical bundle were investigated and compared with those of the monomeric chromophore. The strongly absorbing multichromophoric system combines interesting features: it has a high molecular first-order hyperpolarisability and a very large dipolar moment (μ=38 D) which reveal a self-arrangement of the dipolar chromophores within the supermolecule. The confinement of the push-pull chromophores within the nanoscopic bundle affects their optical properties and promotes interactions: The multichromophoric supermolecule is hypochromically and hypsochromically shifted with respect to its monomeric analogue. In addition, the close proximity promotes excitonic coupling, as well as excimer formation phenomena. |
Evaluation of the separation efficiency of some processes based on interaction of reactive species with a static, spatially periodic potential Article de journal L Jullien; A Lemarchand Journal of Physical Chemistry B, 105 (19), p. 4415–4423, 2001. @article{Jullien:2001a, title = {Evaluation of the separation efficiency of some processes based on interaction of reactive species with a static, spatially periodic potential}, author = {L Jullien and A Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035902352&doi=10.1021%2fjp003532a&partnerID=40&md5=2cf0333f07c719f673415a9141d0597d}, doi = {10.1021/jp003532a}, year = {2001}, date = {2001-01-01}, journal = {Journal of Physical Chemistry B}, volume = {105}, number = {19}, pages = {4415--4423}, abstract = {A procedure is proposed to achieve the selective extraction of any given species from a mixture of closely related molecules exhibiting similar thermodynamic and kinetic properties. It is based on exposing the mixture to a reactive, out-of-equilibrium medium in the presence of a static and spatially periodic potential. Optimal results are obtained upon satisfying stochastic resonance conditions involving the rate constants, the diffusion coefficients of the chemical species, and the characteristic features of the periodic potential. In the case of an electric field, the corresponding relations are shown to be compatible with the current level of experimental achievement.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A procedure is proposed to achieve the selective extraction of any given species from a mixture of closely related molecules exhibiting similar thermodynamic and kinetic properties. It is based on exposing the mixture to a reactive, out-of-equilibrium medium in the presence of a static and spatially periodic potential. Optimal results are obtained upon satisfying stochastic resonance conditions involving the rate constants, the diffusion coefficients of the chemical species, and the characteristic features of the periodic potential. In the case of an electric field, the corresponding relations are shown to be compatible with the current level of experimental achievement. |
Evolution of a chemical system as a trajectory in a phase space. A fruitful picture of the second law Article de journal L Jullien; H Lemarchand Journal of Chemical Education, 78 (6), p. 803–810, 2001. @article{Jullien:2001, title = {Evolution of a chemical system as a trajectory in a phase space. A fruitful picture of the second law}, author = {L Jullien and H Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035366781&partnerID=40&md5=2b72ee0bebcbb0fe5139db918d170852}, year = {2001}, date = {2001-01-01}, journal = {Journal of Chemical Education}, volume = {78}, number = {6}, pages = {803--810}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Femtosecond studies of intramolecular bond twisting in solution Inproceedings M Glasbeek; H Zhang; P Changenet; P Plaza; M M Martin; W Rettig Schryver, De F C; Feyter, De S; Schweitzer, G (Ed.): IVth International Conference on Femtochemistry, p. 417-430, Wiley-VCH, 2001. @inproceedings{RN99, title = {Femtosecond studies of intramolecular bond twisting in solution}, author = {M Glasbeek and H Zhang and P Changenet and P Plaza and M M Martin and W Rettig}, editor = {F C De Schryver and S De Feyter and G Schweitzer}, year = {2001}, date = {2001-01-01}, booktitle = {IVth International Conference on Femtochemistry}, pages = {417-430}, publisher = {Wiley-VCH}, series = {Femtochemistry: With the Nobel Lecture of A. Zewail}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Ionized Aminohydroxycarbene and Its Isomers: Relative Stability and Unimolecular Reactivity Article de journal G Bouchoux; A Espagne Chemical Physics Letters, 348 (3-4), p. 329-336, 2001, ISSN: 0009-2614. @article{RN55, title = {Ionized Aminohydroxycarbene and Its Isomers: Relative Stability and Unimolecular Reactivity}, author = {G Bouchoux and A Espagne}, doi = {10.1016/s0009-2614(01)01117-4}, issn = {0009-2614}, year = {2001}, date = {2001-01-01}, journal = {Chemical Physics Letters}, volume = {348}, number = {3-4}, pages = {329-336}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Primary events in the photoactive yellow protein chromophore in solution Article de journal P Changenet-Barret; P Plaza; M M Martin Chemical Physics Letters, 336 (5-6), p. 439-444, 2001, ISSN: 0009-2614. @article{RN36, title = {Primary events in the photoactive yellow protein chromophore in solution}, author = {P Changenet-Barret and P Plaza and M M Martin}, url = {<Go to ISI>://000167697200011}, issn = {0009-2614}, year = {2001}, date = {2001-01-01}, journal = {Chemical Physics Letters}, volume = {336}, number = {5-6}, pages = {439-444}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Primary photochemical processes in organic materials in solution Article de journal P Plaza; P Changenet-Barret; D Laage; M Martin Actualite Chimique, (2), p. 37–42, 2001. @article{Plaza:2001, title = {Primary photochemical processes in organic materials in solution}, author = {P Plaza and P Changenet-Barret and D Laage and M Martin}, url = {https://www.scopus.com/record/display.uri?eid=2-s2.0-0035258302&origin=reflist&sort=plf-f&cite=2-s2.0-0035258302&src=s&imp=t&sid=5b7c48bdfaa5afb8c4c7e0247afd59c6&sot=cite&sdt=a&sl=0&recordRank=}, year = {2001}, date = {2001-01-01}, journal = {Actualite Chimique}, number = {2}, pages = {37--42}, abstract = {In this paper, we report on intramolecular electron transfer, distorsional relaxation or isomerization reactions in a few classes of commercial or recently engineered organic compounds in solution. We also show the role of the solvent polarity as well as solvent dynamics in the deactivation pathway and in the reaction kinetics. The reactions are probed in real time by pico-femtosecond transient absorption spectroscopy.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, we report on intramolecular electron transfer, distorsional relaxation or isomerization reactions in a few classes of commercial or recently engineered organic compounds in solution. We also show the role of the solvent polarity as well as solvent dynamics in the deactivation pathway and in the reaction kinetics. The reactions are probed in real time by pico-femtosecond transient absorption spectroscopy. |
Thermosensitive polymer structures based on segmented copolymer networks Article de journal A Laschewsky; O Ouari; C Mangeney; L Jullien Macromolecular Symposia, 164 , p. 293–300, 2001. @article{Laschewsky:2001, title = {Thermosensitive polymer structures based on segmented copolymer networks}, author = {A Laschewsky and O Ouari and C Mangeney and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035022230&doi=10.1002%2f1521-3900%28200102%29164%3a1%3c293%3a%3aAID-MASY293%3e3.0.CO%3b2-M&partnerID=40&md5=a0fa089fd29cfad0974b838e97a2a438}, doi = {10.1002/1521-3900(200102)164:1<293::AID-MASY293>3.0.CO;2-M}, year = {2001}, date = {2001-01-01}, journal = {Macromolecular Symposia}, volume = {164}, pages = {293--300}, abstract = {Segmented polymer networks with LCST-behavior have been prepared by free radical initiated copolymerization of α,ω-bis-methacrylate terminated poly(methyl vinyl ether) (PMVE) with 2-hydroxy ethyl methacrylate (HEMA) or butyl acrylate (BA). The PMVE bis-macromonomers have been obtained via a semi-continuous process by end-capping the living cationic polymerization of methyl vinyl ether (MVE) with HEMA. The phase separation temperature can be varied by changing the PMVE/comonomer ratio. Incorporation of PMVE-grafts in the hydrogels increases the rate of deswelling and improves the mechanical properties. The application of the segmented networks for thermo-controllable solid phase extraction has been demonstrated by their thermosensitive adsorption behavior of toluene from a water solution.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Segmented polymer networks with LCST-behavior have been prepared by free radical initiated copolymerization of α,ω-bis-methacrylate terminated poly(methyl vinyl ether) (PMVE) with 2-hydroxy ethyl methacrylate (HEMA) or butyl acrylate (BA). The PMVE bis-macromonomers have been obtained via a semi-continuous process by end-capping the living cationic polymerization of methyl vinyl ether (MVE) with HEMA. The phase separation temperature can be varied by changing the PMVE/comonomer ratio. Incorporation of PMVE-grafts in the hydrogels increases the rate of deswelling and improves the mechanical properties. The application of the segmented networks for thermo-controllable solid phase extraction has been demonstrated by their thermosensitive adsorption behavior of toluene from a water solution. |
2000 |
Diffusion of reactive species tuned by modulated external fields: Application to high performance chromatography Article de journal L Jullien; A Lemarchand; H Lemarchand Journal of Chemical Physics, 112 (19), p. 8293–8301, 2000. @article{Jullien:2000, title = {Diffusion of reactive species tuned by modulated external fields: Application to high performance chromatography}, author = {L Jullien and A Lemarchand and H Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0011581281&doi=10.1063%2f1.481434&partnerID=40&md5=f676c1604ecc9229e75b9fcff8ff0f96}, doi = {10.1063/1.481434}, year = {2000}, date = {2000-01-01}, journal = {Journal of Chemical Physics}, volume = {112}, number = {19}, pages = {8293--8301}, abstract = {In order to improve the separation of any given chemical species from a mixture of compounds with close thermodynamic and kinetic properties, we propose a new chromatography procedure in the presence of a uniform time-periodic field. In the framework of a macroscopic reaction-diffusion model in an external field, we prove that the apparent motion of the chemical species is of diffusion type and determine an approximate analytical expression for the effective diffusion coefficient. Considering this coefficient as a function of the rate constants and maximizing it leads to specific relations between rate constants and field properties interpreted as stochastic resonances. In the case of an electric field, we show that these constraints are compatible with typical experimental values. © 2000 American Institute of Physics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In order to improve the separation of any given chemical species from a mixture of compounds with close thermodynamic and kinetic properties, we propose a new chromatography procedure in the presence of a uniform time-periodic field. In the framework of a macroscopic reaction-diffusion model in an external field, we prove that the apparent motion of the chemical species is of diffusion type and determine an approximate analytical expression for the effective diffusion coefficient. Considering this coefficient as a function of the rate constants and maximizing it leads to specific relations between rate constants and field properties interpreted as stochastic resonances. In the case of an electric field, we show that these constraints are compatible with typical experimental values. © 2000 American Institute of Physics. |
Excited-State Dynamics in Polar Solvents of Push - Pull Polyenes Designed for Nonlinear Optics Article de journal P Plaza; D Laage; M M Martin; V Alain; M Blanchard-Desce; W H Thompson; J T Hynes Journal of Physical Chemistry A, 104 (11), p. 2396-2401, 2000, (cited By 27). @article{Plaza20002396, title = {Excited-State Dynamics in Polar Solvents of Push - Pull Polyenes Designed for Nonlinear Optics}, author = {P Plaza and D Laage and M M Martin and V Alain and M {Blanchard-Desce} and W H Thompson and J T Hynes}, doi = {10.1021/jp992282z}, year = {2000}, date = {2000-01-01}, journal = {Journal of Physical Chemistry A}, volume = {104}, number = {11}, pages = {2396-2401}, abstract = {Subpicosecond spectroscopy of push - pull polyenes, previously designed to achieve large optical nonlinearities, reveals an isosbestic point in the time-resolved gain band in polar solvents. The compounds possess a diethylthiobarbituric acid electron-withdrawing group and a dibutylaniline electron-releasing group coupled by a $pi$-conjugated chain. The final gain peak exhibits a regular red shift with increasing chain length, whereas the ground-state absorption shift levels off. A fast photoinduced process toward a rigid, fully conjugated cyanine-like structure is proposed. This observation supports a recent proposal that a proper description of the excited-state dynamics of these push - pull polyenes requires more than two valence bond states.}, note = {cited By 27}, keywords = {}, pubstate = {published}, tppubtype = {article} } Subpicosecond spectroscopy of push - pull polyenes, previously designed to achieve large optical nonlinearities, reveals an isosbestic point in the time-resolved gain band in polar solvents. The compounds possess a diethylthiobarbituric acid electron-withdrawing group and a dibutylaniline electron-releasing group coupled by a $pi$-conjugated chain. The final gain peak exhibits a regular red shift with increasing chain length, whereas the ground-state absorption shift levels off. A fast photoinduced process toward a rigid, fully conjugated cyanine-like structure is proposed. This observation supports a recent proposal that a proper description of the excited-state dynamics of these push - pull polyenes requires more than two valence bond states. |
Multichromophoric cyclodextrins. 8. Dynamics of homo- and heterotransfer of excitation energy in inclusion complexes with fluorescent dyes Article de journal M N Berberan-Santos; P Choppinet; A Fedorov; L Jullien; B Valeur Journal of the American Chemical Society, 122 (48), p. 11876–11886, 2000. @article{Berberan-Santos:2000, title = {Multichromophoric cyclodextrins. 8. Dynamics of homo- and heterotransfer of excitation energy in inclusion complexes with fluorescent dyes}, author = {M N Berberan-Santos and P Choppinet and A Fedorov and L Jullien and B Valeur}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034614079&doi=10.1021%2fja000995l&partnerID=40&md5=52ae95b5bfa2c9c36c7202004715d451}, doi = {10.1021/ja000995l}, year = {2000}, date = {2000-01-01}, journal = {Journal of the American Chemical Society}, volume = {122}, number = {48}, pages = {11876--11886}, abstract = {The water-soluble β-cyclodextrin, CD-St, with seven steroidic naphthalene chromophores linked to the primary rim, can form inclusion complexes with a merocyanine dye (DCMOH) and an oxazine dye (Ox725); the stoichiometry is 2:1 (CD-St:dye). This system works as an antenna since the dye is surrounded by 14 chromophores. The efficiency of transfer from the antenna chromophores to the encased dye was found to be close to 100%. The dynamics of this heterotransfer and homotransfer (i.e., energy hopping among the antenna chromophores) was investigated by time-resolved fluorescence intensity and time-resolved fluorescence anisotropy experiments, respectively. The distribution of rate constants for homotransfer was recovered thanks to a previously described Monte Carlo simulation from which an average rate constant was calculated and found to be about 4 x 1011 s-1. This value is about 10 times faster than the rate constant for heterotransfer in the case of Ox725, and about three times faster than in the case of DCMOH. The results are discussed in terms of interchromophoric distances, mutual orientations and Forster radii.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The water-soluble β-cyclodextrin, CD-St, with seven steroidic naphthalene chromophores linked to the primary rim, can form inclusion complexes with a merocyanine dye (DCMOH) and an oxazine dye (Ox725); the stoichiometry is 2:1 (CD-St:dye). This system works as an antenna since the dye is surrounded by 14 chromophores. The efficiency of transfer from the antenna chromophores to the encased dye was found to be close to 100%. The dynamics of this heterotransfer and homotransfer (i.e., energy hopping among the antenna chromophores) was investigated by time-resolved fluorescence intensity and time-resolved fluorescence anisotropy experiments, respectively. The distribution of rate constants for homotransfer was recovered thanks to a previously described Monte Carlo simulation from which an average rate constant was calculated and found to be about 4 x 1011 s-1. This value is about 10 times faster than the rate constant for heterotransfer in the case of Ox725, and about three times faster than in the case of DCMOH. The results are discussed in terms of interchromophoric distances, mutual orientations and Forster radii. |
1999 |
100 Q.C.M. corrigés de Biologie, physique, chimie : Concours d'entrée kiné, sage-femme, ergothérapeutes, techniciens en analyse biomédicale, manipulateurs d'électroradiologie médicale Livre Eric Labbe 1999, ISBN: 2224025653. @book{Eric_Labbe34041583, title = {100 Q.C.M. corrig\'{e}s de Biologie, physique, chimie : Concours d'entr\'{e}e kin\'{e}, sage-femme, ergoth\'{e}rapeutes, techniciens en analyse biom\'{e}dicale, manipulateurs d'\'{e}lectroradiologie m\'{e}dicale}, author = {Eric Labbe}, isbn = {2224025653}, year = {1999}, date = {1999-01-01}, keywords = {}, pubstate = {published}, tppubtype = {book} } |
A new fluorescent probe for studies of interactions between hydrophobic oligonucleotides and cellular membranes Article de journal C Gosse; A S Boutorine; L Jullien; C Hélène Nucleosides and Nucleotides, 18 (6-7), p. 1473–1476, 1999. @article{Gosse:1999, title = {A new fluorescent probe for studies of interactions between hydrophobic oligonucleotides and cellular membranes}, author = {C Gosse and A S Boutorine and L Jullien and C H\'{e}l\`{e}ne}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032780790&doi=10.1080%2f07328319908044757&partnerID=40&md5=a66f0dd32d9fd907157f39ab4d0d9e6e}, doi = {10.1080/07328319908044757}, year = {1999}, date = {1999-01-01}, journal = {Nucleosides and Nucleotides}, volume = {18}, number = {6-7}, pages = {1473--1476}, abstract = {The synthesis of a new fluorescently labeled medium-sensitive lipophilic oligonucleotide is reported. A fluorescent chalcone chromophore was introduced between the 5' end of the nucleic acid and the fatty hydrocarbon chains. A blue shift of both absorption and emission wavelength maxima results from a transfer of the chromophore to a more hydrophobic medium or upon binding of the conjugate to unilamellar vesicles of egg phosphatidyl choline. These conjugates could be used as markers for cell uptake studies of lipophilic nucleic acid derivatives.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The synthesis of a new fluorescently labeled medium-sensitive lipophilic oligonucleotide is reported. A fluorescent chalcone chromophore was introduced between the 5' end of the nucleic acid and the fatty hydrocarbon chains. A blue shift of both absorption and emission wavelength maxima results from a transfer of the chromophore to a more hydrophobic medium or upon binding of the conjugate to unilamellar vesicles of egg phosphatidyl choline. These conjugates could be used as markers for cell uptake studies of lipophilic nucleic acid derivatives. |
Coiling of cylindrical membrane stacks with anchored polymers Article de journal V Frette; I Tsafrir; M -A Guedeau-Boudeville; L Jullien; D Kandel; J Stavans Physical Review Letters, 83 (12), p. 2465–2468, 1999. @article{Frette:1999, title = {Coiling of cylindrical membrane stacks with anchored polymers}, author = {V Frette and I Tsafrir and M -A Guedeau-Boudeville and L Jullien and D Kandel and J Stavans}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001682275&doi=10.1103%2fPhysRevLett.83.2465&partnerID=40&md5=b08a889760d34f23aa3c60bb6ebac403}, doi = {10.1103/PhysRevLett.83.2465}, year = {1999}, date = {1999-01-01}, journal = {Physical Review Letters}, volume = {83}, number = {12}, pages = {2465--2468}, abstract = {We study experimentally a coiling instability of cylindrical multilamellar stacks of phospholipid membranes, induced by polymers with hydrophobic anchors grafted along their hydrophilic backbone. We interpret our experimental results in terms of a model in which local membrane curvature and polymer concentration are coupled. The model predicts the occurrence of maximally tight coils above a threshold polymer concentration. Indeed, only maximally tight coils are observed experimentally. Our system is unique in that coils form in the absence of twist and adhesion. © 1999 The American Physical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We study experimentally a coiling instability of cylindrical multilamellar stacks of phospholipid membranes, induced by polymers with hydrophobic anchors grafted along their hydrophilic backbone. We interpret our experimental results in terms of a model in which local membrane curvature and polymer concentration are coupled. The model predicts the occurrence of maximally tight coils above a threshold polymer concentration. Indeed, only maximally tight coils are observed experimentally. Our system is unique in that coils form in the absence of twist and adhesion. © 1999 The American Physical Society. |
Imaging vesicle adhesion by evanescent wave-induced fluorescence Article de journal A -L Bernard; M -A Guedeau-Boudeville; L Jullien; J -M Di Meglio Europhysics Letters, 46 (1), p. 101–106, 1999. @article{Bernard:1999, title = {Imaging vesicle adhesion by evanescent wave-induced fluorescence}, author = {A -L Bernard and M -A Guedeau-Boudeville and L Jullien and J -M Di Meglio}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033106602&doi=10.1209%2fepl%2fi1999-00567-2&partnerID=40&md5=49cb98f45a9c22589a42dc9ffaa0630c}, doi = {10.1209/epl/i1999-00567-2}, year = {1999}, date = {1999-01-01}, journal = {Europhysics Letters}, volume = {46}, number = {1}, pages = {101--106}, abstract = {We present a new method to study the adsorption of vesicles on solid substrates, combining the use of the evanescent wave-induced fluorescence (EWIF) and classical optical microscopy. We show in this paper that our method can clearly discriminate between a spherical vesicle just touching the substrate and a spread vesicle: this method should thus be useful to design and tailor substrates for controlled adhesion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a new method to study the adsorption of vesicles on solid substrates, combining the use of the evanescent wave-induced fluorescence (EWIF) and classical optical microscopy. We show in this paper that our method can clearly discriminate between a spherical vesicle just touching the substrate and a spread vesicle: this method should thus be useful to design and tailor substrates for controlled adhesion. |
Multichromophoric cyclodextrins as fluorescent sensors. Interaction of heptachromophoric β-cyclodextrins with surfactants Article de journal P Choppinet; L Jullien; B Valeur Journal of the Chemical Society. Perkin Transactions 2, (2), p. 249–255, 1999. @article{Choppinet:1999a, title = {Multichromophoric cyclodextrins as fluorescent sensors. Interaction of heptachromophoric β-cyclodextrins with surfactants}, author = {P Choppinet and L Jullien and B Valeur}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001332443&partnerID=40&md5=8fdc2aafe919e03c5bf3b8fac4c62aad}, year = {1999}, date = {1999-01-01}, journal = {Journal of the Chemical Society. Perkin Transactions 2}, number = {2}, pages = {249--255}, abstract = {A β-cyclodextrin derivative CD-NA bearing 7 negatively charged naphthoate chromophores is shown to strongly interact with cationic surfactants. In the absence of surfactant, the CD-NA emission spectrum is composed of two bands: one is assigned to the normal fluorescence and the other one to the fluorescence of intramolecular excimers. Interaction with a cationic surfactant leads to a drop in excimer emission. The ratio of the fluorescence intensities of the monomer and excimer bands is directly related to the concentration of the surfactant. In the case of electroactive surfactants such as cetylpyridimum chloride, the fluorescence quenching arising from photoinduced electron transfer can be additionally used for sensing. CD-NA can thus be used to detect cetyltrimethylammonium chloride (cetyl = hexadecyl) and cetylpyridinium chloride in an aqueous solution at concentrations as low as a few micromoles per litre and up to about 50 micromoles per litre. The interaction between CD-NA and cationic surfactants can be interpreted by a micellization process induced by CD-NA rather than by the formation of 1 : 1 inclusion complexes. The analogy with the interaction between cationic surfactants and polyelectrolytes bearing negative charges is outlined. It should be noted that addition of the anionic surfactant sodium dodecyl sulfate does not induce any photophysical effect.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A β-cyclodextrin derivative CD-NA bearing 7 negatively charged naphthoate chromophores is shown to strongly interact with cationic surfactants. In the absence of surfactant, the CD-NA emission spectrum is composed of two bands: one is assigned to the normal fluorescence and the other one to the fluorescence of intramolecular excimers. Interaction with a cationic surfactant leads to a drop in excimer emission. The ratio of the fluorescence intensities of the monomer and excimer bands is directly related to the concentration of the surfactant. In the case of electroactive surfactants such as cetylpyridimum chloride, the fluorescence quenching arising from photoinduced electron transfer can be additionally used for sensing. CD-NA can thus be used to detect cetyltrimethylammonium chloride (cetyl = hexadecyl) and cetylpyridinium chloride in an aqueous solution at concentrations as low as a few micromoles per litre and up to about 50 micromoles per litre. The interaction between CD-NA and cationic surfactants can be interpreted by a micellization process induced by CD-NA rather than by the formation of 1 : 1 inclusion complexes. The analogy with the interaction between cationic surfactants and polyelectrolytes bearing negative charges is outlined. It should be noted that addition of the anionic surfactant sodium dodecyl sulfate does not induce any photophysical effect. |
Multichromophoric cyclodextrins, part 7: Photophysical and structural features of inclusion complexes with fluorescent dyes Article de journal P Choppinet; L Jullien; B Valeur Chemistry - A European Journal, 5 (12), p. 3666–3678, 1999. @article{Choppinet:1999, title = {Multichromophoric cyclodextrins, part 7: Photophysical and structural features of inclusion complexes with fluorescent dyes}, author = {P Choppinet and L Jullien and B Valeur}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032776997&partnerID=40&md5=1b37ae7ec0106c482165361a54b12291}, year = {1999}, date = {1999-01-01}, journal = {Chemistry - A European Journal}, volume = {5}, number = {12}, pages = {3666--3678}, abstract = {The synthesis of a new water-soluble β-cyclodextrin CD-St, with seven steroidic naphthalene chromophores linked to the primary rim, is reported together with the photophysical and structural features of its inclusion complexes with merocyanine and oxazine fluorescent dyes. These complexes were formed in a buffer at pH 10. At this pH the cyclodextrin is 14 times negatively charged since each chromophore bears two carboxylic groups. No excimer emission was detected, as expected from the design principles. Two complexes can be formed with stoichiometries 1:1 and 2:1 (CD:dye) for both dyes. The respective association constants were determined. In the 2:1 complexes, the cyclodextrin secondary rims are facing each other. Such complexes are outstanding artificial antennae with 14 chromophores surrounding an energy acceptor. Comparison was made with another (previously reported) water-soluble β-cyclodextrin CD-NA with seven naphthalene chromophores - also linked to the primary rim - but bearing only one carboxylic group each. In fact, CD-NA only forms 1:1 complexes with the same dyes. The difference in complexing ability of CD-NA and CD-St is discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The synthesis of a new water-soluble β-cyclodextrin CD-St, with seven steroidic naphthalene chromophores linked to the primary rim, is reported together with the photophysical and structural features of its inclusion complexes with merocyanine and oxazine fluorescent dyes. These complexes were formed in a buffer at pH 10. At this pH the cyclodextrin is 14 times negatively charged since each chromophore bears two carboxylic groups. No excimer emission was detected, as expected from the design principles. Two complexes can be formed with stoichiometries 1:1 and 2:1 (CD:dye) for both dyes. The respective association constants were determined. In the 2:1 complexes, the cyclodextrin secondary rims are facing each other. Such complexes are outstanding artificial antennae with 14 chromophores surrounding an energy acceptor. Comparison was made with another (previously reported) water-soluble β-cyclodextrin CD-NA with seven naphthalene chromophores - also linked to the primary rim - but bearing only one carboxylic group each. In fact, CD-NA only forms 1:1 complexes with the same dyes. The difference in complexing ability of CD-NA and CD-St is discussed. |
Multichromophoric cyclodextrins. 6. Investigation of excitation energy hopping by Monte-Carlo simulations and time-resolved fluorescence anisotropy Article de journal M N Berberan-Santos; P Choppinet; A Fedorov; L Jullien; B Valeur Journal of the American Chemical Society, 121 (11), p. 2526–2533, 1999. @article{Berberan-Santos:1999, title = {Multichromophoric cyclodextrins. 6. Investigation of excitation energy hopping by Monte-Carlo simulations and time-resolved fluorescence anisotropy}, author = {M N Berberan-Santos and P Choppinet and A Fedorov and L Jullien and B Valeur}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033599566&doi=10.1021%2fja983601n&partnerID=40&md5=c22d6aad0691447e272018e264831012}, doi = {10.1021/ja983601n}, year = {1999}, date = {1999-01-01}, journal = {Journal of the American Chemical Society}, volume = {121}, number = {11}, pages = {2526--2533}, abstract = {Excitation energy transport in several β-cyclodextrins containing seven appended chromophores was studied theoretically and experimentally by steady- state and time-resolved fluorescence anisotropy. The absorption spectra compared to those of reference chromophores did not reveal significant interactions between the chromophores in the ground state, thus allowing us to assume a very weak coupling regime for energy transfer. The measured long time anisotropies were found to be in all cases close to one-seventh of the fundamental anisotropy, showing that the chromophores are randomly oriented. A realistic model in which the chromophores are in fixed positions but randomly oriented was developed to interpret the steady-state and time- resolved emission anisotropy data. A Monte-Carlo simulation based on the appropriate master equation allowed the calculation of the theoretical anisotropy decay in terms of reduced variables and parameters. The decay contains a wide spectrum of rate constants. A good fit to the experimental decays was obtained. Moreover, the nearest-neighbor distance recovered from the anisotropy and the steady-state anisotropy for all cyclodextrins (5-7 r{A} in all cases) are compatible with the nearest-neighbor distances expected from molecular modeling, which confirms the validity of the theoretical model.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Excitation energy transport in several β-cyclodextrins containing seven appended chromophores was studied theoretically and experimentally by steady- state and time-resolved fluorescence anisotropy. The absorption spectra compared to those of reference chromophores did not reveal significant interactions between the chromophores in the ground state, thus allowing us to assume a very weak coupling regime for energy transfer. The measured long time anisotropies were found to be in all cases close to one-seventh of the fundamental anisotropy, showing that the chromophores are randomly oriented. A realistic model in which the chromophores are in fixed positions but randomly oriented was developed to interpret the steady-state and time- resolved emission anisotropy data. A Monte-Carlo simulation based on the appropriate master equation allowed the calculation of the theoretical anisotropy decay in terms of reduced variables and parameters. The decay contains a wide spectrum of rate constants. A good fit to the experimental decays was obtained. Moreover, the nearest-neighbor distance recovered from the anisotropy and the steady-state anisotropy for all cyclodextrins (5-7 Å in all cases) are compatible with the nearest-neighbor distances expected from molecular modeling, which confirms the validity of the theoretical model. |
Self-assembly of Janus cyclodextrins at the air-water interface and in organic solvents Article de journal B Hamelin; L Jullien; A Laschewsky; C Hervé Du Penhoat Chemistry - A European Journal, 5 (2), p. 546–556, 1999. @article{Hamelin:1999, title = {Self-assembly of Janus cyclodextrins at the air-water interface and in organic solvents}, author = {B Hamelin and L Jullien and A Laschewsky and C Herv\'{e} Du Penhoat}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033046267&doi=10.1002%2f%28SICI%291521-3765%2819990201%295%3a2%3c546%3a%3aAID-CHEM546%3e3.0.CO%3b2-I&partnerID=40&md5=1aa2c5f97b3dfcdef0f221c8c886e0dc}, doi = {10.1002/(SICI)1521-3765(19990201)5:2<546::AID-CHEM546>3.0.CO;2-I}, year = {1999}, date = {1999-01-01}, journal = {Chemistry - A European Journal}, volume = {5}, number = {2}, pages = {546--556}, abstract = {The self-organization of various amphiphilic cyclodextrins is reported at the air-water interface as well as in organic solvents. These rather rigid molecules expose different molecular surfaces to the external medium according to the nature of the environment, and consequently several types of association are observed. At the air-water interface, stable mono-and multilayers are formed whose behavior can be related to the molecular structure of the amphiphilic compounds. In apolar aromatic solvents, such as benzene or toluene, dimerization occurs as shown by vapour pressure osmometry (VPO), 1H NMR spectroscopy and 1H13C heteronuclear NOE measurements. Such a feature is absent in organic solvents that compete for the formation of hydrogen bonds. The consequences of these results concerning the use of cyclodextrin derivatives as calibration standards for the determination of molecular weights are discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The self-organization of various amphiphilic cyclodextrins is reported at the air-water interface as well as in organic solvents. These rather rigid molecules expose different molecular surfaces to the external medium according to the nature of the environment, and consequently several types of association are observed. At the air-water interface, stable mono-and multilayers are formed whose behavior can be related to the molecular structure of the amphiphilic compounds. In apolar aromatic solvents, such as benzene or toluene, dimerization occurs as shown by vapour pressure osmometry (VPO), 1H NMR spectroscopy and 1H13C heteronuclear NOE measurements. Such a feature is absent in organic solvents that compete for the formation of hydrogen bonds. The consequences of these results concerning the use of cyclodextrin derivatives as calibration standards for the determination of molecular weights are discussed. |
Thermodynamic Behavior of a Supramolecular System Self-Assembled by Electrostatic Interaction in Aqueous Solution. Results and Theoretical Analysis Article de journal L Jullien; H Cottet; B Hamelin; A Jardy Journal of Physical Chemistry B, 103 (49), p. 10866–10875, 1999. @article{Jullien:1999, title = {Thermodynamic Behavior of a Supramolecular System Self-Assembled by Electrostatic Interaction in Aqueous Solution. Results and Theoretical Analysis}, author = {L Jullien and H Cottet and B Hamelin and A Jardy}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001597844&partnerID=40&md5=ea841685fb09dc1a9df850eb4e6a2b9f}, year = {1999}, date = {1999-01-01}, journal = {Journal of Physical Chemistry B}, volume = {103}, number = {49}, pages = {10866--10875}, abstract = {The acid-base and association properties of oppositely charged cyclodextrins in aqueous solution have been investigated by potentiometry. The experimental thermodynamic constants can be analyzed with a theoretical approach leading to structural data in satisfactory agreement with the crystallographic structures of the parent compounds and previous NMR investigations. The corresponding theory is expected to be helpful for understanding and for predicting the behavior of many supramolecular systems involving charged organic molecules.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The acid-base and association properties of oppositely charged cyclodextrins in aqueous solution have been investigated by potentiometry. The experimental thermodynamic constants can be analyzed with a theoretical approach leading to structural data in satisfactory agreement with the crystallographic structures of the parent compounds and previous NMR investigations. The corresponding theory is expected to be helpful for understanding and for predicting the behavior of many supramolecular systems involving charged organic molecules. |
Towards highly efficient nonlinear optical chromophores: molecular engineering of octupolar molecules Article de journal M Blanchard-Desce; J -B Baudin; L Jullien; R Lome; O Ruel; S Brasselet; J Zyss 12 (2), p. 333–338, 1999. @article{Blanchard-Desce:1999, title = {Towards highly efficient nonlinear optical chromophores: molecular engineering of octupolar molecules}, author = {M Blanchard-Desce and J -B Baudin and L Jullien and R Lome and O Ruel and S Brasselet and J Zyss}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032599630&doi=10.1016%2fS0925-3467%2899%2900059-2&partnerID=40&md5=608ca6fec7e1b491b2489ad8d402903e}, doi = {10.1016/S0925-3467(99)00059-2}, year = {1999}, date = {1999-01-01}, volume = {12}, number = {2}, pages = {333--338}, abstract = {Octupolar molecules are of particular interest in the field of nonlinear optics due to their potentially large two or three-dimensional quadratic nonlinearities. In order to design molecules combining enhanced first hyperpolarizabilities and excellent transparency, we have implemented an original strategy based upon adequate functionalization of an orthogonalized biphenyl core. We have designed novel 3-dimensional all-organic octupoles of D2d symmetry and investigated their optical nonlinearities by performing harmonic light scattering experiments in solution. By grafting four electron-donating and/or electron withdrawing substituents on the central biphenyl unit, large molecular nonlinearities (β) have been achieved while maintaining full transparency in the visible range. Molecules displaying larger nonlinearities and better transparency than pNA have been obtained. Molecular optimization has been further pursued via tethering elongated conjugated spikes on the central biphenyl core and taking advantage of multidimensional charge transfer leading to 3D-octupolar molecules displaying both larger nonlinearity and broader transparency than DR1 (up to βxyz = 145 × 10-30 esu with λmax = 400 nm).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Octupolar molecules are of particular interest in the field of nonlinear optics due to their potentially large two or three-dimensional quadratic nonlinearities. In order to design molecules combining enhanced first hyperpolarizabilities and excellent transparency, we have implemented an original strategy based upon adequate functionalization of an orthogonalized biphenyl core. We have designed novel 3-dimensional all-organic octupoles of D2d symmetry and investigated their optical nonlinearities by performing harmonic light scattering experiments in solution. By grafting four electron-donating and/or electron withdrawing substituents on the central biphenyl unit, large molecular nonlinearities (β) have been achieved while maintaining full transparency in the visible range. Molecules displaying larger nonlinearities and better transparency than pNA have been obtained. Molecular optimization has been further pursued via tethering elongated conjugated spikes on the central biphenyl core and taking advantage of multidimensional charge transfer leading to 3D-octupolar molecules displaying both larger nonlinearity and broader transparency than DR1 (up to βxyz = 145 × 10-30 esu with λmax = 400 nm). |
1998 |
How does the gibbs free energy evolve in a system undergoing coupled competitive reactions? Article de journal L Jullien; A Proust; J -C Le Menn Journal of Chemical Education, 75 (2), p. 194–199, 1998. @article{Jullien:1998, title = {How does the gibbs free energy evolve in a system undergoing coupled competitive reactions?}, author = {L Jullien and A Proust and J -C Le Menn}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0039784723&partnerID=40&md5=9b76ac0d9cea46672dc9ee93fc16e5be}, year = {1998}, date = {1998-01-01}, journal = {Journal of Chemical Education}, volume = {75}, number = {2}, pages = {194--199}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Self-assembly of a molecular capsule driven by electrostatic interaction in aqueous solution Article de journal B Hamelin; L Jullien; C Derouet; C H Du Penhoat; P Berthault Journal of the American Chemical Society, 120 (33), p. 8438–8447, 1998. @article{Hamelin:1998, title = {Self-assembly of a molecular capsule driven by electrostatic interaction in aqueous solution}, author = {B Hamelin and L Jullien and C Derouet and C H Du Penhoat and P Berthault}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032569193&doi=10.1021%2fja980046g&partnerID=40&md5=c9d806283a479743d90bfd37476a326d}, doi = {10.1021/ja980046g}, year = {1998}, date = {1998-01-01}, journal = {Journal of the American Chemical Society}, volume = {120}, number = {33}, pages = {8438--8447}, abstract = {A self-assembling molecular capsule based on electrostatic interaction has been designed and its structure is investigated by dynamic 1H NMR. The hydrodynamic description resulting from relaxation and PGSE 1H NMR experiments indicates that association between oppositely charged hydrophilic β-cyclodextrin derivatives in 50 mM KCl aqueous solution corresponds to dimerization with an interdistance between interacting units lying in the 0.4-1.1 nm range with a maximal probability at 0.6 nm.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A self-assembling molecular capsule based on electrostatic interaction has been designed and its structure is investigated by dynamic 1H NMR. The hydrodynamic description resulting from relaxation and PGSE 1H NMR experiments indicates that association between oppositely charged hydrophilic β-cyclodextrin derivatives in 50 mM KCl aqueous solution corresponds to dimerization with an interdistance between interacting units lying in the 0.4-1.1 nm range with a maximal probability at 0.6 nm. |
1997 |
Does aggregation modulate the apparent association constant of host-guest complexes and related species? Article de journal B Hamelin; L Jullien Journal of the Chemical Society - Faraday Transactions, 93 (12), p. 2153–2160, 1997. @article{Hamelin:1997, title = {Does aggregation modulate the apparent association constant of host-guest complexes and related species?}, author = {B Hamelin and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748597387&doi=10.1039%2fa700730b&partnerID=40&md5=d8bad9212598488e98e6367d09cd6f83}, doi = {10.1039/a700730b}, year = {1997}, date = {1997-01-01}, journal = {Journal of the Chemical Society - Faraday Transactions}, volume = {93}, number = {12}, pages = {2153--2160}, abstract = {The present paper illustrates the consequences of aggregation phenomena on the apparent association constant of a host-guest system in three different cases. In the first, the guest gives aggregates whereas in the second the host exhibits aggregation while maintaining a constant affinity for the guest. In the last case under examination, it is the host-guest species that is assumed to aggregate. Numerical simulations based on widely used experimental protocols emphasized the significance of aggregation phenomena on apparent association constants under a broad range of circumstances. The possible relevance of the present analysis to real systems is discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present paper illustrates the consequences of aggregation phenomena on the apparent association constant of a host-guest system in three different cases. In the first, the guest gives aggregates whereas in the second the host exhibits aggregation while maintaining a constant affinity for the guest. In the last case under examination, it is the host-guest species that is assumed to aggregate. Numerical simulations based on widely used experimental protocols emphasized the significance of aggregation phenomena on apparent association constants under a broad range of circumstances. The possible relevance of the present analysis to real systems is discussed. |
Dynamic behavior of a perfunctionalized β-cyclodextrin as probed by NMR and molecular modeling Article de journal L Catoire; V Michon; L Monville; A Hocquet; L Jullien; J Canceill; J -M Lehn; M Piotto; C H Du Penhoat Carbohydrate Research, 303 (4), p. 379–393, 1997. @article{Catoire:1997a, title = {Dynamic behavior of a perfunctionalized β-cyclodextrin as probed by NMR and molecular modeling}, author = {L Catoire and V Michon and L Monville and A Hocquet and L Jullien and J Canceill and J -M Lehn and M Piotto and C H Du Penhoat}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030730720&doi=10.1016%2fS0008-6215%2897%2900188-2&partnerID=40&md5=5a1d95947c311db10fcad166684adcfe}, doi = {10.1016/S0008-6215(97)00188-2}, year = {1997}, date = {1997-01-01}, journal = {Carbohydrate Research}, volume = {303}, number = {4}, pages = {379--393}, abstract = {Conformational analysis of a perfunctionalized β-cyclodextrin by NMR and molecular modeling has revealed that this compound exists as an equilibrium mixture of C1 and C7 conformers in slow exchange. From carbon chemical shifts, interglycosidic vicinal heteronuclear coupling constants and NOESY volumes, it has been demonstrated that the macrocyclic conformation is responsable for the asymmetry in the C1 form. Several dynamic processes such as rapid conformational averaging, localized chemical exchange and the C1/C7 equilibrium have been shown to occur on widely separated timescales. In parallel, a molecular modeling study has revealed that the accessible conformational space of β-CDs is not significantly reduced with respect to that of the related disaccharide, β-maltose. All of the dynamic phenomena appear to be related to the macrocylic puckering and two distinct modes of variation in puckering have emerged from MD trajectories: transitions are either auto-compensated without perceptible change in macrocycle puckering or irreversible leading to considerable variation in macrocycle puckering. Optimization of the NMR-defined theoretical structures leads to auto- complexation of an exocyclic substituent.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Conformational analysis of a perfunctionalized β-cyclodextrin by NMR and molecular modeling has revealed that this compound exists as an equilibrium mixture of C1 and C7 conformers in slow exchange. From carbon chemical shifts, interglycosidic vicinal heteronuclear coupling constants and NOESY volumes, it has been demonstrated that the macrocyclic conformation is responsable for the asymmetry in the C1 form. Several dynamic processes such as rapid conformational averaging, localized chemical exchange and the C1/C7 equilibrium have been shown to occur on widely separated timescales. In parallel, a molecular modeling study has revealed that the accessible conformational space of β-CDs is not significantly reduced with respect to that of the related disaccharide, β-maltose. All of the dynamic phenomena appear to be related to the macrocylic puckering and two distinct modes of variation in puckering have emerged from MD trajectories: transitions are either auto-compensated without perceptible change in macrocycle puckering or irreversible leading to considerable variation in macrocycle puckering. Optimization of the NMR-defined theoretical structures leads to auto- complexation of an exocyclic substituent. |
pH-dependent specific binding and combing of DNA Article de journal J -F Allemand; D Bensimon; L Jullien; A Bensimon; V Croquette Biophysical Journal, 73 (4), p. 2064–2070, 1997. @article{Allemand:1997, title = {pH-dependent specific binding and combing of DNA}, author = {J -F Allemand and D Bensimon and L Jullien and A Bensimon and V Croquette}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030881494&doi=10.1016%2fS0006-3495%2897%2978236-5&partnerID=40&md5=67fabb87ba140361b6bc5c28e2ea523a}, doi = {10.1016/S0006-3495(97)78236-5}, year = {1997}, date = {1997-01-01}, journal = {Biophysical Journal}, volume = {73}, number = {4}, pages = {2064--2070}, abstract = {Recent developments in the rapid sequencing, mapping, and analysis of DNA rely on the specific binding of DNA to specially treated surfaces. We show here that specific binding of DNA via its unmodified extremities can be achieved on a great variety of surfaces by a judicious choice of the pH. On hydrophobic surfaces the best binding efficiency is reached at a pH of textasciitilde5.5. At that pH textasciitilde40-kbp DNA is 10 times more likely to bind by an extremity than by a midsegment. A model is proposed to account for the differential adsorption of the molecule extremities and midsection as a function of pH. The pH-dependent specific binding can be used to align anchored DNA molecules by a receding meniscus, a process called molecular combing. The resulting properties of the combed molecules will be discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recent developments in the rapid sequencing, mapping, and analysis of DNA rely on the specific binding of DNA to specially treated surfaces. We show here that specific binding of DNA via its unmodified extremities can be achieved on a great variety of surfaces by a judicious choice of the pH. On hydrophobic surfaces the best binding efficiency is reached at a pH of textasciitilde5.5. At that pH textasciitilde40-kbp DNA is 10 times more likely to bind by an extremity than by a midsegment. A model is proposed to account for the differential adsorption of the molecule extremities and midsection as a function of pH. The pH-dependent specific binding can be used to align anchored DNA molecules by a receding meniscus, a process called molecular combing. The resulting properties of the combed molecules will be discussed. |
1996 |
Interaction, lipid exchange, and effect of vesicle size in systems of oppositely charged vesicles Article de journal V Marchi-Artzner; L Jullien; L Belloni; D Raison; L Lacombe; J -M Lehn Journal of Physical Chemistry, 100 (32), p. 13844–13856, 1996. @article{Marchi-Artzner:1996, title = {Interaction, lipid exchange, and effect of vesicle size in systems of oppositely charged vesicles}, author = {V Marchi-Artzner and L Jullien and L Belloni and D Raison and L Lacombe and J -M Lehn}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000460872&doi=10.1021%2fjp960327f&partnerID=40&md5=3795a27b061ada113fcc14c7fe016f95}, doi = {10.1021/jp960327f}, year = {1996}, date = {1996-01-01}, journal = {Journal of Physical Chemistry}, volume = {100}, number = {32}, pages = {13844--13856}, abstract = {The interactions between charged unilamellar vesicles of different size prepared from mixtures of egg lecithin (EPC1), cholesterol, and a charged component, either stearylamine or dicetyl phosphate, were investigated. Several techniques, i.e. fluorescence spectroscopy, 133Cs-NMR, light scattering measurements, and electron and optical microscopies in dilute aqueous solutions, provided evidence that vesicles bearing opposite charges interact via contact followed by lipid exchange; the progressive charge neutralization is shown by 133Cs-NMR to occur without fusion of vesicle internal pools. Vesicle size determines as diverse features as contact duration, extent of lipid exchange, and final distribution of surface charge among the vesicle mixture. © 1996 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interactions between charged unilamellar vesicles of different size prepared from mixtures of egg lecithin (EPC1), cholesterol, and a charged component, either stearylamine or dicetyl phosphate, were investigated. Several techniques, i.e. fluorescence spectroscopy, 133Cs-NMR, light scattering measurements, and electron and optical microscopies in dilute aqueous solutions, provided evidence that vesicles bearing opposite charges interact via contact followed by lipid exchange; the progressive charge neutralization is shown by 133Cs-NMR to occur without fusion of vesicle internal pools. Vesicle size determines as diverse features as contact duration, extent of lipid exchange, and final distribution of surface charge among the vesicle mixture. © 1996 American Chemical Society. |
Multichromophoric cyclodextrins. 3. Investigation of dynamics of energy hopping by frequency-domain fluorometry Article de journal M N Berberan-Santos; J Canceill; E Gratton; L Jullien; J -M Lehn; P So; J Sutin; B Valeur Journal of Physical Chemistry, 100 (1), p. 15–20, 1996. @article{Berberan-Santos:1996, title = {Multichromophoric cyclodextrins. 3. Investigation of dynamics of energy hopping by frequency-domain fluorometry}, author = {M N Berberan-Santos and J Canceill and E Gratton and L Jullien and J -M Lehn and P So and J Sutin and B Valeur}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0003019274&doi=10.1021%2fjp951598d&partnerID=40&md5=99ebe5d1e0d18c77b7580fe2784de54a}, doi = {10.1021/jp951598d}, year = {1996}, date = {1996-01-01}, journal = {Journal of Physical Chemistry}, volume = {100}, number = {1}, pages = {15--20}, abstract = {A β-cyclodextrin labeled with seven naphthoyloxy chromophores was studied by steady-state and time-resolved fluorescence spectroscopy in order to get information on the dynamics of energy hopping between chromophores. The steady-state fluorescence anisotropy was recorded as a function of excitation wavelength in a mixture of methanol and ethanol at 110 K (rigid glass). The fluorescence anisotropy decay was obtained under the same conditions by the multifrequency phase-modulation technique upon excitation at 290 nm. The data were analyzed and interpreted on the basis of a theoretical model involving a unique rate constant for energy hopping between nearest neighbors. In particular, this model predicts a long-time leveling-off of the emission anisotropy at 1/7th of the fundamental anisotropy, which is confirmed by both steady-state and time-resolved data and thus indicates that there is no preferred mutual orientation between the chromophores. As regards the rate of energy hopping, an average value of 2 × 109 s-1 can be deduced from the comparison between the theoretical and experimental decays. This value is shown to be consistent with a dipole-dipole mechanism of energy transfer. © 1996 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A β-cyclodextrin labeled with seven naphthoyloxy chromophores was studied by steady-state and time-resolved fluorescence spectroscopy in order to get information on the dynamics of energy hopping between chromophores. The steady-state fluorescence anisotropy was recorded as a function of excitation wavelength in a mixture of methanol and ethanol at 110 K (rigid glass). The fluorescence anisotropy decay was obtained under the same conditions by the multifrequency phase-modulation technique upon excitation at 290 nm. The data were analyzed and interpreted on the basis of a theoretical model involving a unique rate constant for energy hopping between nearest neighbors. In particular, this model predicts a long-time leveling-off of the emission anisotropy at 1/7th of the fundamental anisotropy, which is confirmed by both steady-state and time-resolved data and thus indicates that there is no preferred mutual orientation between the chromophores. As regards the rate of energy hopping, an average value of 2 × 109 s-1 can be deduced from the comparison between the theoretical and experimental decays. This value is shown to be consistent with a dipole-dipole mechanism of energy transfer. © 1996 American Chemical Society. |