Theoretical determination of the vibrational raman optical activity signatures of helical polypropylene chains

Résultats de recherche: Contribution à un journal/une revueArticle

Résumé

Raman and vibrational Raman optical activity (VROA) spectra of helical conformers of polypropylene chains are simulated using ab initio methods to unravel the relationships between the vibrational signatures and the primary and secondary structures of the chains. For a polypropylene chain containing three units, conformational effects are shown to lead to more acute signatures for VROA than for Raman spectra. In addition to regular polypropylene chains, which can display right and left helicities with the same probability, chirality and therefore helicity are enforced by substituting one chain end with a phenyl group. The simulations predict that the threefold helical structures, which correspond to (TG) conformations of the backbone, have a specific VROA backward signature in the form of an intense couplet around 1100 cm . This couplet is associated with collective wagging and twisting motions, while most of its intensity comes from the anisotropic invariants combining normal coordinate derivatives of the electric dipole-electric dipole polarizability and of the electric dipole-magnetic dipole polarizability. A similar signature has already been found in model helical polyethylene chains, whereas it is very weak in forward VROA.
langue originaleAnglais
Pages (de - à)2366-2376
Nombre de pages11
journalChemPhysChem
Volume7
Numéro de publication11
Les DOIs
étatPublié - 13 nov. 2006

Empreinte digitale

Polypropylenes
optical activity
polypropylene
signatures
electric dipoles
Chirality
Polyethylene
Conformations
Raman scattering
Derivatives
twisting
magnetic dipoles
chirality
polyethylenes
Raman spectra
simulation

Citer ceci

@article{a33baf4fc9f247d4a9a5354019c40e1f,
title = "Theoretical determination of the vibrational raman optical activity signatures of helical polypropylene chains",
abstract = "Raman and vibrational Raman optical activity (VROA) spectra of helical conformers of polypropylene chains are simulated using ab initio methods to unravel the relationships between the vibrational signatures and the primary and secondary structures of the chains. For a polypropylene chain containing three units, conformational effects are shown to lead to more acute signatures for VROA than for Raman spectra. In addition to regular polypropylene chains, which can display right and left helicities with the same probability, chirality and therefore helicity are enforced by substituting one chain end with a phenyl group. The simulations predict that the threefold helical structures, which correspond to (TG) conformations of the backbone, have a specific VROA backward signature in the form of an intense couplet around 1100 cm . This couplet is associated with collective wagging and twisting motions, while most of its intensity comes from the anisotropic invariants combining normal coordinate derivatives of the electric dipole-electric dipole polarizability and of the electric dipole-magnetic dipole polarizability. A similar signature has already been found in model helical polyethylene chains, whereas it is very weak in forward VROA.",
author = "E. Lamparska and V. Li{\'e}geois and O. Quinet and B. Champagne",
note = "Copyright 2006 Elsevier B.V., All rights reserved.",
year = "2006",
month = "11",
day = "13",
doi = "10.1002/cphc.200600451",
language = "English",
volume = "7",
pages = "2366--2376",
journal = "ChemPhysChem",
issn = "1439-4235",
publisher = "Wiley-VCH Verlag",
number = "11",

}

Theoretical determination of the vibrational raman optical activity signatures of helical polypropylene chains. / Lamparska, E.; Liégeois, V.; Quinet, O.; Champagne, B.

Dans: ChemPhysChem, Vol 7, Numéro 11, 13.11.2006, p. 2366-2376.

Résultats de recherche: Contribution à un journal/une revueArticle

TY - JOUR

T1 - Theoretical determination of the vibrational raman optical activity signatures of helical polypropylene chains

AU - Lamparska, E.

AU - Liégeois, V.

AU - Quinet, O.

AU - Champagne, B.

N1 - Copyright 2006 Elsevier B.V., All rights reserved.

PY - 2006/11/13

Y1 - 2006/11/13

N2 - Raman and vibrational Raman optical activity (VROA) spectra of helical conformers of polypropylene chains are simulated using ab initio methods to unravel the relationships between the vibrational signatures and the primary and secondary structures of the chains. For a polypropylene chain containing three units, conformational effects are shown to lead to more acute signatures for VROA than for Raman spectra. In addition to regular polypropylene chains, which can display right and left helicities with the same probability, chirality and therefore helicity are enforced by substituting one chain end with a phenyl group. The simulations predict that the threefold helical structures, which correspond to (TG) conformations of the backbone, have a specific VROA backward signature in the form of an intense couplet around 1100 cm . This couplet is associated with collective wagging and twisting motions, while most of its intensity comes from the anisotropic invariants combining normal coordinate derivatives of the electric dipole-electric dipole polarizability and of the electric dipole-magnetic dipole polarizability. A similar signature has already been found in model helical polyethylene chains, whereas it is very weak in forward VROA.

AB - Raman and vibrational Raman optical activity (VROA) spectra of helical conformers of polypropylene chains are simulated using ab initio methods to unravel the relationships between the vibrational signatures and the primary and secondary structures of the chains. For a polypropylene chain containing three units, conformational effects are shown to lead to more acute signatures for VROA than for Raman spectra. In addition to regular polypropylene chains, which can display right and left helicities with the same probability, chirality and therefore helicity are enforced by substituting one chain end with a phenyl group. The simulations predict that the threefold helical structures, which correspond to (TG) conformations of the backbone, have a specific VROA backward signature in the form of an intense couplet around 1100 cm . This couplet is associated with collective wagging and twisting motions, while most of its intensity comes from the anisotropic invariants combining normal coordinate derivatives of the electric dipole-electric dipole polarizability and of the electric dipole-magnetic dipole polarizability. A similar signature has already been found in model helical polyethylene chains, whereas it is very weak in forward VROA.

UR - http://www.scopus.com/inward/record.url?scp=33751213901&partnerID=8YFLogxK

U2 - 10.1002/cphc.200600451

DO - 10.1002/cphc.200600451

M3 - Article

VL - 7

SP - 2366

EP - 2376

JO - ChemPhysChem

JF - ChemPhysChem

SN - 1439-4235

IS - 11

ER -