title: Star-Shaped Conjugated Molecules with Oxa- or Thiadiazole Bithiophene Side Arms.
abstract: Star-shaped conjugated molecules, consisting of a benzene central unit symmetrically trisubstituted with either oxa- or thiadiazole bithiophene groups, were synthesized as promising molecules and building blocks for application in (opto)electronics and electrochromic devices. Their optical (Eg (opt)) as well as electrochemical (Eg (electro)) band gaps depended on the type of the side arm and the number of solubilizing alkyl substituents. Oxadiazole derivatives showed Eg (opt) slightly below 3 eV and by 0.2 eV larger than those determined for thiadiazole-based compounds. The presence of alkyl substituents in the arms additionally lowered the band gap. The obtained compounds were efficient electroluminophores in guest/host-type light-emitting diodes. They also showed a strong tendency to self-organize in monolayers deposited on graphite, as evidenced by scanning tunneling microscopy. The structural studies by X-ray scattering revealed the formation of supramolecular columnar stacks in which the molecules were organized. Differences in macroscopic alignment in the specimen indicated variations in the self-assembly mechanism between the molecules. The compounds as trifunctional monomers were electrochemically polymerized to yield the corresponding polymer network. As shown by UV/Vis-NIR spectroelectrochemical studies, these networks exhibited reversible electrochromic behavior both in the oxidation and in the reduction modes.
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00664, Warsaw, Poland.
authors.forename: Kamil
authors.initials: K
authors.lastname: Kotwica
authors.affiliation: Department of Organic Chemistry, Omsk F. M. Dostoevsky State University, Mira av. 55A, Omsk, Russian Federation.|Laboratory of New Organic Materials, Omsk State Technical University, Mira av. 11, Omsk, 644050, Russian Federation.
authors.forename: Anastasia S
authors.initials: AS
authors.lastname: Kostyuchenko
authors.affiliation: Physics Department, University of Durham, South Road, Durham, DH1 3LE, United Kingdom.
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Data
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Marszalek
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00664, Warsaw, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Skorka
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01224, Warsaw, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Jaroch
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00664, Warsaw, Poland.
authors.forename: Sylwia
authors.initials: S
authors.lastname: Kacka
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00664, Warsaw, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Zagorska
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01224, Warsaw, Poland.
authors.forename: Robert
authors.initials: R
authors.lastname: Nowakowski
authors.affiliation: Physics Department, University of Durham, South Road, Durham, DH1 3LE, United Kingdom.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Monkman
authors.affiliation: Department of Organic Chemistry, Omsk F. M. Dostoevsky State University, Mira av. 55A, Omsk, Russian Federation. fisyuk@chemomsu.ru.|Laboratory of New Organic Materials, Omsk State Technical University, Mira av. 11, Omsk, 644050, Russian Federation. fisyuk@chemomsu.ru.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Fisyuk
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany. pisula@mpip-mainz.mpg.de.|Department of Molecular Physics, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland. pisula@mpip-mainz.mpg.de.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Pisula
authors.affiliation: Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00664, Warsaw, Poland. apron@ch.pw.edu.pl.
authors.forename: Adam
authors.initials: A
authors.lastname: Pron
keywords: electron transport; host-guest systems; self-assembly; semiconductors; supramolecular chemistry