title: Helically Coiled Graphene Nanoribbons.
abstract: Graphene is a zero-gap, semiconducting 2D material that exhibits outstanding charge-transport properties. One way to open a band gap and make graphene useful as a semiconducting material is to confine the electron delocalization in one dimension through the preparation of graphene nanoribbons (GNR). Although several methods have been reported so far, solution-phase, bottom-up synthesis is the most promising in terms of structural precision and large-scale production. Herein, we report the synthesis of a well-defined, helically coiled GNR from a polychlorinated poly(m-phenylene) through a regioselective photochemical cyclodehydrochlorination (CDHC) reaction. The structure of the helical GNR was confirmed by1H NMR, FT-IR, XPS, TEM, and Raman spectroscopy. This Riemann surface-like GNR has a band gap of 2.15 eV and is highly emissive in the visible region, both in solution and the solid state.
authors.affiliation: Département de chimie and Centre de Recherche sur les Matériaux Avancés (CERMA), Université Laval, 1045 Ave de la Médecine, Québec, G1V 0A6, Canada.
authors.forename: Maxime
authors.initials: M
authors.lastname: Daigle
authors.affiliation: Département de chimie and Centre de Recherche sur les Matériaux Avancés (CERMA), Université Laval, 1045 Ave de la Médecine, Québec, G1V 0A6, Canada.
authors.forename: Dandan
authors.initials: D
authors.lastname: Miao
authors.affiliation: Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133, Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lucotti
authors.affiliation: Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133, Milano, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Tommasini
authors.affiliation: Département de chimie and Centre de Recherche sur les Matériaux Avancés (CERMA), Université Laval, 1045 Ave de la Médecine, Québec, G1V 0A6, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Morin
keywords: carbon materials; graphene nanoribbons; helical polymer; helicenes; photochemistry