title: Liquid crystalline metal-free phthalocyanines designed for charge and exciton transport.
abstract: A joint theoretical and experimental study of the electronic and structural properties of liquid crystalline metal-free phthalocyanines bearing a strong potential for charge and exciton transport has been performed. The synthesis of such compounds has been triggered by quantum chemical calculations showing that: (i) hole transport is favored in metal-free phthalocyanines by their extremely low reorganization energy (0.045 eV) and large electronic splittings; and (ii) the efficiency of energy transfer along the one-dimensional discotic stacks is weakly affected by rotational disorder due to the two-dimensional character of the molecules. We have synthesized two metal-free phthalocyanines with different branched aliphatic chains on the gram scale to allow for a full characterization of their solid-state properties. The two compounds self-organize in liquid crystalline mesophases, as evidenced by optical microscopy, differential scanning calorimetry, X-ray powder diffraction, and molecular dynamics simulations. They exhibit a columnar rectangular mesophase at room temperature and a columnar hexagonal mesophase at elevated temperature.
authors.affiliation: Laboratoire de Chimie des Polymères, Université Libre de Bruxelles, CP 206/1 Boulevard du Triomphe, B-1050 Brussels, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Tant
authors.forename: Yves Henri
authors.initials: YH
authors.lastname: Geerts
authors.forename: Matthias
authors.initials: M
authors.lastname: Lehmann
authors.forename: Vinciane
authors.initials: V
authors.lastname: De Cupere
authors.forename: Gaël
authors.initials: G
authors.lastname: Zucchi
authors.forename: Bo Wegge
authors.initials: BW
authors.lastname: Laursen
authors.forename: Thomas
authors.initials: T
authors.lastname: Bjørnholm
authors.forename: Vincent
authors.initials: V
authors.lastname: Lemaur
authors.forename: Valérie
authors.initials: V
authors.lastname: Marcq
authors.forename: Anick
authors.initials: A
authors.lastname: Burquel
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Hennebicq
authors.forename: Fabrice
authors.initials: F
authors.lastname: Gardebien
authors.forename: Pascal
authors.initials: P
authors.lastname: Viville
authors.forename: David
authors.initials: D
authors.lastname: Beljonne
authors.forename: Roberto
authors.initials: R
authors.lastname: Lazzaroni
authors.forename: Jérôme
authors.initials: J
authors.lastname: Cornil