title: Extended pi-conjugated dendrimers based on truxene.
abstract: The largest pi-conjugated dendrimers containing up to nine 10,15-dihydro-5H-diindeno[1,2-alpha;1',2';-c]fluorene (truxene) moieties have been prepared with good yields by repetitive Friedel-Crafts acetylation and acid-promoted cyclotrimerization reactions. An alternative approach to the convergent synthesis of desired dendrimers has been developed, in which the core is generated "in-situ" by acid-promoted cyclotrimerizations of aryl methyl ketones. This proves valuable to afford large-size and precisely well-defined dendrimers in an accelerated dendrimer-growth strategy utilizing enlarged repeat units. The increasing amount of SiCl4 dramatically improves the yield of cyclotrimerization reactions. The introduction of hexahexyl groups onto C-5, C-10, C-15 positions of the truxene moiety greatly enhances the solubility of our compounds. Further investigation indicates that the torsion angle between the truxene segment and the benzene ring might play a key role in determining the photo properties of pi-conjugated dendrimers.
authors.affiliation: The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P R China.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Cao
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Zhang
authors.forename: Jin-Liang
authors.initials: JL
authors.lastname: Wang
authors.forename: Xing-Hua
authors.initials: XH
authors.lastname: Zhou
authors.forename: Hua
authors.initials: H
authors.lastname: Lu
authors.forename: Jian
authors.initials: J
authors.lastname: Pei