Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement

Molecular modeling techniques are applied to polyesteramides designed as PNOBDME (C 34H 38 N2O 6 ) n and PNOBEE (C 26H22 N2O 6 ) n, synthesized and characterized as cholesteric liquid crystals -through the condensation reaction between 4 and 40-(terephthaloyl- diaminedibenzoic chloride (NOBC) and ra...

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Autores: Pérez Méndez, Mercedes, Fayos Alcañíz, José, Meunier, Marc
Tipo de recurso: otro
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/267415
Acceso en línea:http://hdl.handle.net/10261/267415
Access Level:acceso abierto
Palabra clave:Cholesteric Liquid-Crystal Polyesteramides
Molecular modeling
WAXS synchrotron radiation source
Conformational Analysis
Rietveld refinement
Crystal polymeric chains models
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spelling Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld RefinementPérez Méndez, MercedesFayos Alcañíz, JoséMeunier, MarcCholesteric Liquid-Crystal PolyesteramidesMolecular modelingWAXS synchrotron radiation sourceConformational AnalysisRietveld refinementCrystal polymeric chains modelsMolecular modeling techniques are applied to polyesteramides designed as PNOBDME (C 34H 38 N2O 6 ) n and PNOBEE (C 26H22 N2O 6 ) n, synthesized and characterized as cholesteric liquid crystals -through the condensation reaction between 4 and 40-(terephthaloyl- diaminedibenzoic chloride (NOBC) and racemic glycol: DL-1,2 dodecanediol, or DL-1,2-butanediol, respectively, being chemical modificationsof precursor multifunctional cholesteric LC polyesters, adding new properties but holding their helical macromolecular structures. Although the starting raw materials were racemic, these cholesteric LC polymers exhibit unexpected optical activity and chiral morphology. For that reason, conformational analysis is studied on the monomer models of PNOBDME and PNOBEE. Four helical conformers models, experimentally observed by NMR, are proposed for each cholesteric polyesteramide: Rgg, Rgt, Sgg, Sgt. Polymerization of the monomeric conformers, with minima energies, have been simulated and used to reproduce the crystalline fraction observed by x-ray diffraction. Three orders of chirality are observed in the structure of the polymer chains: One due to the asymmetric carbon atoms, a second chirality due to the two successive rotations of the benzene groups, along the main chain, within the monomer which implies the formation of helical molecules, for both R and S chirality and still, a third chirality corresponding to the twisting of the rigid/semirigid cholesteric LC polymer chains. All these factors contributing to the net optical activity observed in these materials. Crystal packing is simulated in triclinic primitive P1cells, with molecular chains oriented parallel to the z-axis (c lattice parameter equal to the pitch length of each simulated polymer helix) and parameters a, b, α, β and γ, obtained by Pawley refinement from the known structures of precursor polyesters. The simulated x-ray diffraction patterns of the proposed crystal models fit, after successive Pawley and Rietveld refinement cycles, the experimental WAXS. Powder Quantitative Phase Analysis applied to an ideal mixture with the four possible helical conformers, for each degree of polymerization, allows to refine their relative weight and determine the major phase relative amount. These results would confirm the theory of a preferable recrystallization, among the four possible helical diastereoisomers, depending on the synthetic conditions.We thank CSIC for its facilities. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewedInTechOpenCSIC - Unidad de Recursos de Información Científica para la Investigación (URICI)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2022202220222022info:eu-repo/semantics/otherhttp://purl.org/coar/resource_type/c_3248Publisher's versioninfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/bookParthttp://hdl.handle.net/10261/267415reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.5772/intechopen.100388Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2674152026-05-22T06:33:51Z
dc.title.none.fl_str_mv Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
title Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
spellingShingle Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
Pérez Méndez, Mercedes
Cholesteric Liquid-Crystal Polyesteramides
Molecular modeling
WAXS synchrotron radiation source
Conformational Analysis
Rietveld refinement
Crystal polymeric chains models
title_short Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
title_full Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
title_fullStr Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
title_full_unstemmed Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
title_sort Molecular Simulation of Cholesteric Liquid-Crystal Polyesteramides: Conformational and Structure Analysis by Rietveld Refinement
dc.creator.none.fl_str_mv Pérez Méndez, Mercedes
Fayos Alcañíz, José
Meunier, Marc
author Pérez Méndez, Mercedes
author_facet Pérez Méndez, Mercedes
Fayos Alcañíz, José
Meunier, Marc
author_role author
author2 Fayos Alcañíz, José
Meunier, Marc
author2_role author
author
dc.contributor.none.fl_str_mv CSIC - Unidad de Recursos de Información Científica para la Investigación (URICI)
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Cholesteric Liquid-Crystal Polyesteramides
Molecular modeling
WAXS synchrotron radiation source
Conformational Analysis
Rietveld refinement
Crystal polymeric chains models
topic Cholesteric Liquid-Crystal Polyesteramides
Molecular modeling
WAXS synchrotron radiation source
Conformational Analysis
Rietveld refinement
Crystal polymeric chains models
description Molecular modeling techniques are applied to polyesteramides designed as PNOBDME (C 34H 38 N2O 6 ) n and PNOBEE (C 26H22 N2O 6 ) n, synthesized and characterized as cholesteric liquid crystals -through the condensation reaction between 4 and 40-(terephthaloyl- diaminedibenzoic chloride (NOBC) and racemic glycol: DL-1,2 dodecanediol, or DL-1,2-butanediol, respectively, being chemical modificationsof precursor multifunctional cholesteric LC polyesters, adding new properties but holding their helical macromolecular structures. Although the starting raw materials were racemic, these cholesteric LC polymers exhibit unexpected optical activity and chiral morphology. For that reason, conformational analysis is studied on the monomer models of PNOBDME and PNOBEE. Four helical conformers models, experimentally observed by NMR, are proposed for each cholesteric polyesteramide: Rgg, Rgt, Sgg, Sgt. Polymerization of the monomeric conformers, with minima energies, have been simulated and used to reproduce the crystalline fraction observed by x-ray diffraction. Three orders of chirality are observed in the structure of the polymer chains: One due to the asymmetric carbon atoms, a second chirality due to the two successive rotations of the benzene groups, along the main chain, within the monomer which implies the formation of helical molecules, for both R and S chirality and still, a third chirality corresponding to the twisting of the rigid/semirigid cholesteric LC polymer chains. All these factors contributing to the net optical activity observed in these materials. Crystal packing is simulated in triclinic primitive P1cells, with molecular chains oriented parallel to the z-axis (c lattice parameter equal to the pitch length of each simulated polymer helix) and parameters a, b, α, β and γ, obtained by Pawley refinement from the known structures of precursor polyesters. The simulated x-ray diffraction patterns of the proposed crystal models fit, after successive Pawley and Rietveld refinement cycles, the experimental WAXS. Powder Quantitative Phase Analysis applied to an ideal mixture with the four possible helical conformers, for each degree of polymerization, allows to refine their relative weight and determine the major phase relative amount. These results would confirm the theory of a preferable recrystallization, among the four possible helical diastereoisomers, depending on the synthetic conditions.
publishDate 2022
dc.date.none.fl_str_mv 2022
2022
2022
2022
dc.type.none.fl_str_mv info:eu-repo/semantics/other
http://purl.org/coar/resource_type/c_3248
Publisher's version
info:eu-repo/semantics/publishedVersion
dc.type.openaire.fl_str_mv info:eu-repo/semantics/bookPart
format other
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/267415
url http://hdl.handle.net/10261/267415
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.5772/intechopen.100388
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv InTechOpen
publisher.none.fl_str_mv InTechOpen
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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