You will find below the publication list of our pole.
For the publication list of each pole member, please see his/her personal webpage.
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. |
Multichromophoric cyclodextrins. 4. Light conversion by antenna effect Article de journal L Jullien; J Canceill; B Valeur; E Bardez; J -P Lefèvre; J -M Lehn; V Marchi-Artzner; R Pansu Journal of the American Chemical Society, 118 (23), p. 5432–5442, 1996. @article{Jullien:1996, title = {Multichromophoric cyclodextrins. 4. Light conversion by antenna effect}, author = {L Jullien and J Canceill and B Valeur and E Bardez and J -P Lef\`{e}vre and J -M Lehn and V Marchi-Artzner and R Pansu}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029953291&doi=10.1021%2fja954332t&partnerID=40&md5=86be6c0094475ed11e09091268977ba1}, doi = {10.1021/ja954332t}, year = {1996}, date = {1996-01-01}, journal = {Journal of the American Chemical Society}, volume = {118}, number = {23}, pages = {5432--5442}, abstract = {A water soluble β-cyclodextrin (CD-NA) bearing seven naphthoyl chromophores forms very stable 1:1 complexes with a merocyanine laser dye DCM-OH (4-(dicyanomethylene)-2-methyl-6-(p-(bis(hydroxyethyl)amino)-styryl)-4 H-pyran). The antenna effect, i.e. energy transfer from the naphthoyl antenna chromophores to the encased dye, is shown to occur with 100% efficiency. The stability of the complexes is very high (K(s) textasciitilde 105) owing to the contribution of the naphthoate residues. The structural features of the complexes have been examined in detail: circular dichroism experiments confirm the expected axial orientation of DCM-OH in the cavity of CD-NA, and fluorescence anisotropy measurements together with 13C-NMR longitudinal relaxation time measurements show that the complex formed between CD-NA and DCM-OH is tight. The mechanisms of homotransfer (i.e., between naphthoate chromophores) and heterotransfer (i.e., from naphthoate chromophores to DCM-OH included in the cavity) are discussed in light of existing theories. In both cases, the major contribution arises more likely from Coulombic interaction than from short-range interactions. Such multichromophoric cyclodextrins are good models for mimicry of the antenna function in photosynthesis and show great promise as photochemical microreactors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A water soluble β-cyclodextrin (CD-NA) bearing seven naphthoyl chromophores forms very stable 1:1 complexes with a merocyanine laser dye DCM-OH (4-(dicyanomethylene)-2-methyl-6-(p-(bis(hydroxyethyl)amino)-styryl)-4 H-pyran). The antenna effect, i.e. energy transfer from the naphthoyl antenna chromophores to the encased dye, is shown to occur with 100% efficiency. The stability of the complexes is very high (K(s) textasciitilde 105) owing to the contribution of the naphthoate residues. The structural features of the complexes have been examined in detail: circular dichroism experiments confirm the expected axial orientation of DCM-OH in the cavity of CD-NA, and fluorescence anisotropy measurements together with 13C-NMR longitudinal relaxation time measurements show that the complex formed between CD-NA and DCM-OH is tight. The mechanisms of homotransfer (i.e., between naphthoate chromophores) and heterotransfer (i.e., from naphthoate chromophores to DCM-OH included in the cavity) are discussed in light of existing theories. In both cases, the major contribution arises more likely from Coulombic interaction than from short-range interactions. Such multichromophoric cyclodextrins are good models for mimicry of the antenna function in photosynthesis and show great promise as photochemical microreactors. |
1995 |
Drug delivery: Piercing vesicles by their adsorption onto a porous medium Article de journal M -A Guedeau-Boudeville; L Jullien; J -M Di Meglio Proceedings of the National Academy of Sciences of the United States of America, 92 (21), p. 9590–9592, 1995. @article{Guedeau-Boudeville:1995, title = {Drug delivery: Piercing vesicles by their adsorption onto a porous medium}, author = {M -A Guedeau-Boudeville and L Jullien and J -M Di Meglio}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028820145&doi=10.1073%2fpnas.92.21.9590&partnerID=40&md5=251b948d8859e06857263108f1f5e581}, doi = {10.1073/pnas.92.21.9590}, year = {1995}, date = {1995-01-01}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {92}, number = {21}, pages = {9590--9592}, abstract = {Experimental evidence is presented that supports the possibility of building a 'molecular drill.' By the adsorption of a vesicle onto a porous substrate (specifically, a lycopode grain), it was possible to increase the permeability of the vesicle by locally stretching its membrane. Molecules contained within the vesicle, which could not cross the membrane, were delivered to the porous substrate upon adsorption. This general process could provide another method for drug delivery and targeting.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Experimental evidence is presented that supports the possibility of building a 'molecular drill.' By the adsorption of a vesicle onto a porous substrate (specifically, a lycopode grain), it was possible to increase the permeability of the vesicle by locally stretching its membrane. Molecules contained within the vesicle, which could not cross the membrane, were delivered to the porous substrate upon adsorption. This general process could provide another method for drug delivery and targeting. |
Formation of highly stable heterodimers in aqueous solution between β-cyclodextrin derivatives bearing multiple opposite charges Article de journal B Hamelin; L Jullien; F Guillo; J -M Lehn; A Jardy; L De Robertis; H Driguez Journal of Physical Chemistry, 99 (51), p. 17877–17885, 1995. @article{Hamelin:1995, title = {Formation of highly stable heterodimers in aqueous solution between β-cyclodextrin derivatives bearing multiple opposite charges}, author = {B Hamelin and L Jullien and F Guillo and J -M Lehn and A Jardy and L De Robertis and H Driguez}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000285072&partnerID=40&md5=34255c509ef04ce2b93b4a7f1cf9684a}, year = {1995}, date = {1995-01-01}, journal = {Journal of Physical Chemistry}, volume = {99}, number = {51}, pages = {17877--17885}, abstract = {Two water-soluble perfunctionalized β-cyclodextrins bearing amino or carboxyl groups were used to examine the possibility of obtaining stable heterodimers in water. The acidobasic properties of both compounds may be accounted for on the basis of a theoretical interpretation of the potentiometric titration of polyelectrolytes. The association constants between positively and negatively charged β-cyclodextrins were determined by potentiometric titrations. The Gibbs energies of association between cyclodextrins are shown to depend on the product of elementary charges borne by each interacting species. The results obtained are significant for evaluation of electrostatic contributions to molecular recognition. © 1995 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two water-soluble perfunctionalized β-cyclodextrins bearing amino or carboxyl groups were used to examine the possibility of obtaining stable heterodimers in water. The acidobasic properties of both compounds may be accounted for on the basis of a theoretical interpretation of the potentiometric titration of polyelectrolytes. The association constants between positively and negatively charged β-cyclodextrins were determined by potentiometric titrations. The Gibbs energies of association between cyclodextrins are shown to depend on the product of elementary charges borne by each interacting species. The results obtained are significant for evaluation of electrostatic contributions to molecular recognition. © 1995 American Chemical Society. |
1994 |
ELECTROCHEMICAL ACTIVATION OF BROMOTRIFLUOROMETHANE : A NEW METHOD TO PREPARE TRIFLUOROMETHYLATED COMPOUNDS Inproceedings Jean-Michel Paratian; Eric Labbe; Soline Sibille; Jean-Yves Nedelec; Jacques Perichon Torii, Sigeru (Ed.): Novel trends in electroorganic synthesis - proceedings of the Second International Symposium on Electroorganic Synthesis, Kurashiki, September 27 - 30, 1994 and Pre-Symposium on Novel Aspects of Electrogenerated Active Species, Okayama, September 24 - 25. 1994, p. 99-102, Tokyo, 1994. @inproceedings{RID:0429150543570-42, title = {ELECTROCHEMICAL ACTIVATION OF BROMOTRIFLUOROMETHANE : A NEW METHOD TO PREPARE TRIFLUOROMETHYLATED COMPOUNDS}, author = {Jean-Michel Paratian and Eric Labbe and Soline Sibille and Jean-Yves Nedelec and Jacques Perichon}, editor = {Sigeru Torii}, year = {1994}, date = {1994-01-01}, booktitle = {Novel trends in electroorganic synthesis - proceedings of the Second International Symposium on Electroorganic Synthesis, Kurashiki, September 27 - 30, 1994 and Pre-Symposium on Novel Aspects of Electrogenerated Active Species, Okayama, September 24 - 25. 1994}, pages = {99-102}, address = {Tokyo}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |