title: Synthesis and Chiroptical Properties of Hexa-, Octa-, and Deca-azaborahelicenes: Influence of Helicene Size and of the Number of Boron Atoms.
abstract: Four members of a new class of cycloborylated hexa-, octa-, and deca-helicenes (1 a-d) have been prepared in enantiopure form, along with two cycloplatinated deca-helicenes (1 d', 1 d1), further extending the family of cycloplatinated hexa- and octa-helicenes reported previously. The azabora[n]helicenes display intense electronic circular dichroism and large optical rotations; the dependence of the optical activity on the size of the helix (n=6, 8, 10) and the number of boron atoms (1 or 2) has been examined in detail both experimentally and theoretically. The photophysical properties (nonpolarized and circularly polarized luminescence) of these new fluorescent organic helicenes have been measured and compared with the corresponding organometallic phosphorescent cycloplatinated derivatives (1 a1-d1).
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR 6226, Institut de Physique de Rennes, UMR 6251, Campus de Beaulieu, CNRS-Université de Rennes 1, 35042, Rennes Cedex, France.
authors.forename: Chengshuo
authors.initials: C
authors.lastname: Shen
authors.affiliation: Faculty of Chemistry, Jagiellonian University, R. Ingardena 3, 30-060, Krakow, Poland.
authors.forename: Monika
authors.identifier: 0000-0003-4211-325X
authors.initials: M
authors.lastname: Srebro-Hooper
authors.affiliation: Aix Marseille University, CNRS, Centrale Marseille, iSm2, Marseille, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Jean
authors.affiliation: Aix Marseille University, CNRS, Centrale Marseille, iSm2, Marseille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR 6226, Institut de Physique de Rennes, UMR 6251, Campus de Beaulieu, CNRS-Université de Rennes 1, 35042, Rennes Cedex, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Toupet
authors.affiliation: Department of Chemistry, University of Durham, Durham, DH1 3LE, UK.
authors.forename: J A Gareth
authors.initials: JA
authors.lastname: Williams
authors.affiliation: Department of Chemistry, San José State University, San José, CA, 95192-0101, USA.
authors.forename: Alexis R
authors.initials: AR
authors.lastname: Torres
authors.affiliation: Department of Chemistry, San José State University, San José, CA, 95192-0101, USA.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Riives
authors.affiliation: Department of Chemistry, San José State University, San José, CA, 95192-0101, USA.
authors.forename: Gilles
authors.initials: G
authors.lastname: Muller
authors.affiliation: Department of Chemistry, University at Buffalo - State University of New York, Buffalo, NY, 14260, USA.
authors.forename: Jochen
authors.identifier: 0000-0001-9392-877X
authors.initials: J
authors.lastname: Autschbach
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR 6226, Institut de Physique de Rennes, UMR 6251, Campus de Beaulieu, CNRS-Université de Rennes 1, 35042, Rennes Cedex, France.
authors.forename: Jeanne
authors.identifier: 0000-0002-4037-6067
authors.initials: J
authors.lastname: Crassous
mesh_terms: D001372:Aza Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D011084:Polycyclic Aromatic Hydrocarbons / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001372:Aza Compounds; D001896:Boron Compounds; D011084:Polycyclic Aromatic Hydrocarbons
keywords: boron; circular dichroism; helicenes; luminescence; quantum-chemical calculations