Polymorphs and colors of polydiacetylenes: a first principles study.
Polydiacetylenes (PDAs) are exceptional polymeric materials with pi-conjugated backbones. Several of them can undergo chromogenic transitions under a wide range of external stimuli. Herein we investigate the electronic structure and the resulting properties of model and experimental PDAs, by means of first principles condensed matter calculations. It is shown that torsional isomers with a twist of the lateral groups can be formed at small energetic costs. We also show the relationship that exists between these twists and the observed changes in the electronic and physical properties. In particular, the calculated changes in the absorption, Raman and NMR spectra agree with the color and property changes as observed experimentally. Therefore, these isomers are excellent models for the structures involved in the chromogenic transitions.
Filhol
Jean-Sébastien
JS
Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Université Montpellier 2, Place E. Bataillon, 34095 Montpellier Cedex 5, France. filhol@univ-montp2.fr
Deschamps
Jérôme
J
Dutremez
Sylvain G
SG
Boury
Bruno
B
Barisien
Thierry
T
Legrand
Laurent
L
Schott
Michel
M
D003460:Crystallization; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D000078789:Polyacetylene Polymer; D011108:Polymers / Q000737:chemistry*; D053279:Polyynes / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics
D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; C082361:polydiacetylene