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11. Rectifying antennas for energy harvesting from the microwaves to visible light: A review

Author

Reynaud, C.A., primary, Duché, D., additional, Simon, J.-J., additional, Sanchez-Adaime, E., additional, Margeat, O., additional, Ackermann, J., additional, Jangid, V., additional, Lebouin, C., additional, Brunel, D., additional, Dumur, F., additional, Gigmes, D., additional, Berginc, G., additional, Nijhuis, C.A., additional, and Escoubas, L., additional

Published
2020
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12. Simultaneous initiation of radical and cationic polymerization reactions using the “G1” copper complex as photoredox catalyst: Applications of free radical/cationic hybrid photopolymerization in the composites and 3D printing fields

Author

Mokbel, H., primary, Anderson, D., additional, Plenderleith, R., additional, Dietlin, C., additional, Morlet-Savary, F., additional, Dumur, F., additional, Gigmes, D., additional, Fouassier, J.P., additional, and Lalevée, J., additional

Published
2019
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13. Photoinduced Thermal Polymerization Reactions

Author

Bonardi, A.-H., primary, Bonardi, F., additional, Morlet-Savary, F., additional, Dietlin, C., additional, Noirbent, G., additional, Grant, T. M., additional, Fouassier, J.-P., additional, Dumur, F., additional, Lessard, B. H., additional, Gigmes, D., additional, and Lalevée, J., additional

Published
2018
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14. Apport de l'analyse par Eléments finis à la conception d'un électrolyte de batterie Lithium Métal Polymère

Author

Dufaye, G, Lebon, Frédéric, Gigmes, D, Hochard, C, Maurel, A, Maria, S, Bouchet, R, Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)

Subjects
[SPI]Engineering Sciences [physics]
Abstract

International audience; Un modèle de croissance dendritique simulé par éléments finis est proposé dans ce poster. Ce modèle est notamment basé sur les travaux de Monroe et Newman, pour l’écriture de l’équation de Butler-Volmer modifiée qui permet un couplage entre les effets électrochimiques et les efforts mécaniques subis par la matrice et l’électrolyte positif. Cette équation est résolue spatialement et temporellement par une méthode d’éléments finis afin de suivre l’évolution de la croissance dendritique en fonction des caractéristiques de la matrice polymère.

Published
2016

24. Verwendung einer Inhibitorkombination, Harzmischung, Reaktionsharzmörtel, Zweikomponenten - Mörtelsystem und dessen Verwendung sowie Patrone, Kartusche oder Folienbeutel enthaltend ein Zweikomponenten - Mörtelsystem

Author

PFEIL A., BRINKHORST J., GIGMES D., PRATT D. A., BERTIN D., VALGIMIGLI, LUCA, PFEIL A., BRINKHORST J., GIGMES D., VALGIMIGLI L., PRATT D. A., and BERTIN D.

Subjects
ANCHORING PROCESS, INHIBITORS, COPOLYMERS
Abstract

Verwendung einer Kombination aus einer Verbindung der allgemeinen Formel (I):in der R1 und R2 jeweils unabhängig voneinander Wasserstoff oder eine unverzweigte oder verzweigte C1-C20-Alkylgruppe ist, X -OR3 oder -NR3 2 ist, wobei R3 eine unverzweigte oder verzweigte C1-C20-Alkylgruppe oder eine C2-C4-Polyalkylenoxid-Gruppe ist, und einer Verbindung der allgemeinen Formel (II):in der R Wasserstoff, eine unverzweigte oder verzweigte C1-C18-Alkylgruppe oder -OR3 oder -NR3 2 ist, wobei R3 eine verzweigte oder unverzweigte C1-C20-Alkylgruppe ist, R' Wasserstoff, eine unverzweigte oder verzweigte C1-C18-Alkylgruppe ist und R'' eine unverzweigte oder verzweigte C1-C18-Alkylgruppe ist, zur Einstellung der Reaktivität und der Gelzeit von Harzmischungen auf Basis von radikalisch polymerisierbaren Verbindungen.

Published
2012

25. Chapter 6: Recent developments in nitroxide mediated polymerization

Author

Gigmes, D., Junkers, T., Barner-Kowollik, C., Lalevée, J., Gigmes, D., Junkers, T., Barner-Kowollik, C., and Lalevée, J.

Abstract

The current chapter highlights the latest developments in the fields of enhanced spin capturing polymerization (ESCP), in situ nitroxide mediated radical polymerization (in situ NMP) as well as nitroxide mediated photo-polymerization (NMP2), critically embedded into the latest developments in the wider field of reversible deactivation polymerization. Specific examples for each area are provided, noting the specific advantages and disadvantages of each technique, spanning the fields of block and star copolymer design to spatially resolved gradient surfaces.

Published
2016

26. Synthesis of nitroxides and alkoxyamines

Author

Gigmes, D, Blinco, James, Bottle, Steven, Fairfull-Smith, Kathryn, Simpson, Emily, Thomas, Komba, Gigmes, D, Blinco, James, Bottle, Steven, Fairfull-Smith, Kathryn, Simpson, Emily, and Thomas, Komba

Abstract

Nitroxide mediated polymerization is an important branch of controlled radical polymerisation, which has revolutionised the preparation of polymer architectures and compositions. This is the first book dedicated to the topic and covers the history and development of NMP, as well as current techniques of academic and industrial interest. The book will be of interest to polymer chemists and materials scientists at graduate level and above.

Published
2016

27. Synthesis of New Dendritic Polymeric Adsorbents for Trapping Radioactive Radon

Author

Noel, R., Roy, M., Trang, P., Gigmes, D., Busto, J., Gingras, M., Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), SuperNEMO, and Cristofol, Danielle

Subjects
[CHIM.ORGA]Chemical Sciences/Organic chemistry, [CHIM.ORGA] Chemical Sciences/Organic chemistry
Abstract

Radon is a radioactive Noble gas naturally occurring in air. The most important isotope of this gas is 222Rn, which comes from a 238U decay. 222Rn contributes to most of the natural radioactivity. In particle physics experiments, radon is a principal source of background noise during measurements. It is also the second cause of lungs cancer in the world.1,2 To control 222Rn pollution, activated charcoals are already used as adsorbents, but various types exist, and each one has a wide range of efficiency.3 Furthermore, they are not of a high purity and homogeneity. More importantly, they show some traces of radioactivity (238U, 40K, ...), plus a diffusion of encapsulated radon. One solution to avoid these radioactive contaminants is to make fully organic absorbents, to limit radioactive impurities. Inorganic materials and zeolites are in general not appropriate in this regard. Thus, we are working on new dendritic monomers and polymers, as new entities possessing a covalent pre-organization of cavities toward nanoporous materials, after a potent cross-linkage. Some sulfurated asterisk monomers are quite easy to make (2 to 4 high-yielding steps).4 These monomers were thus polymerized to some extent by radical polymerization, and they will be cross-linked in the future to allow a new avenue for optimized adsorption and chemisorption properties.

Published
2014

28. Poly(methyl methacrylate)-b-poly (n-butyl acrylate)-b-poly(ε-caprolactone) triblock copolymers as tougheners for PMMA matrices

Author

Chagneux, N., Kierkels, J., Leblanc, T., Thomas Trimaille, Meijer, H., Gérard, P., Gigmes, D., Bertin, D., Goossens, H., and Processing and Performance

Subjects
Nitroxide-mediated polymerization, Deformation mechanisms, Toughness, Block copolymers
Abstract

Poly(methyl methacrylate)-b-poly(butyl acrylate)-b-poly(ε-capro-lactone) (PMMA-PBA-PCL) triblock copolymers of typical number-averaged block molecular weights of 45 to 100 kg/mol for PMMA, 25 kg/mol for PBA and 10 kg/mol for PCL were synthesized by sequential nitroxide-mediated polymerization (NMP) of BA and MMA from a SG1 (N-(tert-butyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)) nitroxide-functionalized PCL macroalkoxyamine initiator. This alkoxy-amine was obtained by transformation of an OH-terminated PCL into acrylate-end capped PCL, followed by 1,2-intermolecular radical addition (IRA) of MAMA-SG1 (so-called BlocBuilder® MA). NMP of BA from the macroalkoxyamine proceeded in a controlled manner. The high living chain ratio of PBA-PCL allowed further initiation of NMP of MMA, leading to triblock copolymers with adjustable PMMA block molecular weights. The samples prepared by solvent casting were found to organize in a lamellar morphology for the pure triblock copolymers, and in a spherical morphology when blended with a PMMA homo-polymer of Mn = 40 kg/mol and polydispersity index of 2.1. Finally, the mechanical properties and the local deformation mechanisms of the pure triblock copolymers and their blends with PMMA were investigated by time-resolved SAXS measurements during tensile testing. The dominant microscopic deformation mode of the triblock copolymer was found to change from crazing to cavitation-induced shear yielding, due to the easy-cavitating PCL block of the copolymer.

Published
2014

30. Stimuli-responsive behavior of micelles prepared from a poly(vinyl alcohol)-block-poly(acrylic acid)-block-poly(4-vinylpyridine) triblock terpolymer

Author

UCL - SST/IMCN/BSMA - Bio and soft matter, Poggi, Elio, Guerlain, Claire, Debuigne, A., Detrembleur, C., Gigmes, D., Hoeppener, S., Schubert, U.S., Fustin, Charles-André, Gohy, Jean-François, UCL - SST/IMCN/BSMA - Bio and soft matter, Poggi, Elio, Guerlain, Claire, Debuigne, A., Detrembleur, C., Gigmes, D., Hoeppener, S., Schubert, U.S., Fustin, Charles-André, and Gohy, Jean-François

Abstract

A poly(vinyl alcohol)-block-poly(acrylic acid)-block-poly(4-vinylpyridine) triblock terpolymer (PVOH-b-PAA-b-P4VP) is prepared by hydrolyzing a poly(vinyl acetate)-block-poly(acrylonitrile)-block-poly(4-vinylpyridine) precursor (PVAc-b-PAN-b-P4VP) synthesized by a combination of cobalt-mediated radical polymerization (CMRP) and nitroxide mediated polymerization (NMP). The PVOH-b-PAA-b-P4VP terpolymer is further micellized in water and the accordingly obtained micellar structures are characterized by a combination of dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM) as a function of pH. Well-defined micelles are observed in the whole pH range except for pH values below 4.5 where non-aggregated chains (unimers) are present. The formation of micelles can be rationalized by the formation of insoluble PAA/P4VP inter-polyelectrolyte complexes in the 4.5-6 pH range while hydrophobic P4VP cores are observed at pH values above 6. Finally, the effect of the addition of different salts on the micellar characteristic features is investigated.

Published
2015

33. FUNCTIONALIZATION OF VINYL TERMINATED POLYETHYLENES USING RADICAL MEDIATED THIOL-ENE CHEMISTRY

Author

Mazzolini, J., Monteil, V., D Agosto, F., Christophe Boisson, Gigmes, D., Bertin, D., Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), and Montarnal, Damien

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

34. SANS from hard soft nanocomposites: understanding reinforcement from accurate description of structure to mechanical properties under small and large deformation

Author

Boue, F., Jestin, J., Chloe Chevigny, Gigmes, D., Denis Bertin, Jouault, N., Vallat, P., Florent Dalmas, Said, S., Laboratoire d'Ingénierie des Matériaux de Bretagne (LIMATB), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO), Laboratoire Chimie Provence (LCP), Centre National de la Recherche Scientifique (CNRS)-Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC), and Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2009

35. Novel nanoporous membrane formed in a self-assembly block copolymer

Author

Querelle, S., Ellouze, F., Quemener, D., Perrin, L., Phan, T., Gigmes, D., Bertin, Denis, Deratani, A., Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Laboratoire Chimie Provence (LCP), Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

36. Design of new membranes assisted by block copolymer assembly

Author

Querelle, S., Ellouze, F., Quemener, Damien, Perrin, L., Phan, T., Gigmes, D., Bertin, Denis, Deratani, A., Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Laboratoire Chimie Provence (LCP), Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

37. Aminyl and aminoalkyl radicals: a new access through a direct observation

Author

Lalevee, Jacques, Gigmes, D., Bertin, Denis, Graff, Bernadette, Allonas, Xavier, Fouassier, Jean-Pierre, Département de Photochimie Générale (DPG), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), and Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.POLY]Chemical Sciences/Polymers
Published
2007

38. Ordered nanoporous membranes by self-assembly of polystyrene-b-polyxyethylene-b-polystyrene triblock copolymers

Author

Querelle, S., Perrin, L., Phan, T., Gigmes, D., Bertin, Denis, Deratani, A., Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Laboratoire Chimie Provence (LCP), Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

39. First Effective Nitroxide-Mediated Polymerization of Methyl Methacrylate

Author

Guillaneuf, Y., Gigmes, D., S. R. A., Marque, Tordo, P., Bertin, Denis, Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

40. Interaction of monomer radicals with nitroxides : a new access to the radical combination rate constants

Author

Lalevee, Jacques, Gigmes, D., Bertin, Denis, Allonas, Xavier, Fouassier, Jean-Pierre, Département de Photochimie Générale (DPG), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), and Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.MATE]Chemical Sciences/Material chemistry
Published
2007

41. Alkoxyamine C-ON Bond Homolysis: Stereoelectronic Effects

Author

Beaudoin, E., Bertin, Denis, Gigmes, D., S. R. A., Marque, Siri, D., Tordo, P., Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2006

42. Intramolecular hydrogen bonding

Author

Acerbis, S., Bertin, D., Boutevin, B., Gigmes, D., Lacroix-Desmazes, P., LeMercier, C., Lutz, J.-F., Marque, S.R.A., Siri, D., Tordo, P., and Publica

Published
2006

43. Alkoxyamines of stable aromatic nitroxides: N-O vs. C-O bond homolysis

Author

Gigmes, D., Gaudel-Siri, A., S. R. A., Marque, Bertin, Denis, Tordo, P., Astolfi, P., Greci, L., Rizzoli, C., Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, [CHIM.POLY]Chemical Sciences/Polymers, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2006

44. Highly labile alkoxyamines : homolysis rate constant kd

Author

Bertin, Denis, Marque, S., Tordo, P., Gigmes, D., P.-E., Dufils, Guillaneuf, Y., Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences
Published
2005

45. Control vs. homolysis rate constant of alkoxyamines : Kinetic modeling to improve NMP

Author

Bertin, Denis, Tordo, P., Marque, S., Gigmes, D., Guerret, O., Guillaneuf, Y., Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences
Published
2005

46. Kinetic analysis of NMP : How to obtain high molar masses living controlled polystyrene

Author

Bertin, Denis, Tordo, P., Marque, S., Gigmes, D., Guerret, O., Guillaneuf, Y., Luneau, B., P.-E., Dufils, Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences
Published
2005

47. One step synthesis of NMP star polymer initiator for core first mehod

Author

Bertin, Denis, Tordo, P., Gigmes, D., Guerret, O., P.-E., Dufils, Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), and Nouguier, Colette

Subjects
[CHIM] Chemical Sciences, [CHIM]Chemical Sciences
Published
2005

49. ESR investigation of chemical exchange in geminally diphosphorylated linear nitroxide radicals

Author

UCL - SC/CHIM - Département de chimie, Rockenbauer, A, Olive, G, Rozanska, X, Jacques, Alain, Gigmes, D, Le Moigne, FO, Peeters, Daniel, German, A, Tordo, P., UCL - SC/CHIM - Département de chimie, Rockenbauer, A, Olive, G, Rozanska, X, Jacques, Alain, Gigmes, D, Le Moigne, FO, Peeters, Daniel, German, A, and Tordo, P.

Abstract

For geminally diphosphorylated linear nitroxide radicals, a marked line width alternation (LWA) can be observed. The LWA appears irrespectively whether the investigated radicals R"N(O-.)C(P(O)(OEt)(2))(2)R' contain any chiral group or not. If R" = tert-butyl and R' = H, the small P-hydrogen coupling indicates a completely blocked rotation around the N-C sigma-bond and the LWA can be assigned to a chemical exchange between conformations in which the phosphoryl groups have a symmetric and a nonsymmetric geometry. The conformational change is accompanied by the deformation of the CP2 bonding angle and the rate of exchange is slowed in pentane for which the solvent molecules can be trapped by the chelating phosphoryl groups. If R" = benzyl, both the proton hyperfine lines of the CH2 group and the phosphorus lines of the CP2 group produce a LWA; two coalescences can be observed. In the case of a chiral R" group (R" = secondary butyl, R' = methyl) a tentative four-site model can explain the highly complex LWA.

Published
2004

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