title: Chiroptical properties of carbo[6]helicene derivatives bearing extended π-conjugated cyano substituents.
abstract: New carbo[6]helicene derivatives grafted with π-conjugated cyano-phenyl arms were synthesized in enantiopure forms and their π-conjugation examined by UV-vis spectroscopy. The influence of the π-conjugation on the circular dichroism spectra and molar rotations is discussed based on comparing experimental data with results from quantum-chemical calculations. The results highlight the fact that increasing the spatial extension of the π-system in a helicene molecule is an efficient way of increasing its molar rotation.
authors.affiliation: Institut des Sciences Chimiques de Rennes, Campus de Beaulieu, UMR 6226 CNRS, Université de Rennes 1, Rennes, France.
authors.forename: Mehdi El Sayed
authors.initials: Mel S
authors.lastname: Moussa
authors.forename: Monika
authors.initials: M
authors.lastname: Srebro
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Anger
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.forename: Christian
authors.initials: C
authors.lastname: Roussel
authors.forename: Christophe
authors.initials: C
authors.lastname: Lescop
authors.forename: Jochen
authors.initials: J
authors.lastname: Autschbach
authors.forename: Jeanne
authors.initials: J
authors.lastname: Crassous
keywords: circular dichroism; helicene; pi-conjugation; quantum-chemical calculations