Star‐Shaped Conjugated Molecules with Oxa‐ or Thiadiazole Bithiophene Side Arms. Issue 33 (12th July 2016)

• Record Type: Journal Article
• Authors: Kotwica, Kamil; Kostyuchenko, Anastasia S.; Data, Przemyslaw; Marszalek, Tomasz; Skorka, Lukasz; Jaroch, Tomasz; Kacka, Sylwia; Zagorska, Malgorzata; Nowakowski, Robert; Monkman, Andrew P.; Fisyuk, Alexander S.; Pisula, Wojciech; Pron, Adam
• Is Part Of: Chemistry. Volume 22:Issue 33(2016)
• Page Start: 11795
• Page End: 11806
• Publication Date: 2016-07-12
• Subjects: electron transport -- host–guest systems -- self-assembly -- semiconductors -- supramolecular chemistry; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201600984
• Languages: English
• ISSNs: 0947-6539

Abstract

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 ( E g (opt)) as well as electrochemical ( E g (electro)) band gaps depended on the type of the side arm and the number of solubilizing alkyl substituents. Oxadiazole derivatives showed E g (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. Abstract : Bright stars : Star‐shaped conjugated molecules with oxa‐ or thiadiazole bithiophene side arms were investigated as promising molecules and building blocks for application in (opto)electronics and electrochromic devices (see figure).