TY - JOUR A1 - Schnitzlein, Matthias A1 - Zhu, Chongwei A1 - Shoyama, Kazutaka A1 - Würthner, Frank T1 - π‐Extended Pleiadienes by [5+2] Annulation of 1‐Boraphenalenes and ortho‐Dihaloarenes JF - Chemistry – A European Journal N2 - Palladium‐catalyzed [5+2] annulation of 1‐boraphenalenes with ortho‐dihaloarenes afforded negatively curved π‐extended pleiadienes. Two benzo[1,2‐i:4,5‐i’]dipleiadienes (BDPs) featuring a seven‐six‐seven‐membered ring arrangement were synthesized and investigated. Their crystal structure revealed a unique packing arrangement and theoretical calculations were employed to shed light onto the dynamic behavior of the BDP moiety and its aromaticity. Further, a naphthalene‐fused pleiadiene was stitched together by oxidative cyclodehydrogenation to yield an additional five‐membered ring. This formal azulene moiety led to distinct changes in optical and redox properties and increased perturbation of the aromatic system. KW - annulation KW - aromaticity KW - azulene KW - cyclodehydrogenation KW - polycyclic aromatic hydrocarbons Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293919 VL - 28 IS - 61 ER - TY - JOUR A1 - Schnitzlein, Matthias A1 - Mützel, Carina A1 - Shoyama, Kazutaka A1 - Farrell, Jeffrey M. A1 - Würthner, Frank T1 - PAHs Containing both Heptagon and Pentagon: Corannulene Extension by [5+2] Annulation JF - European Journal of Organic Chemistry N2 - Utilizing Pd‐catalyzed [5+2] annulation a series of heptagon‐extended corannulenes could be synthesized from a borinic acid precursor furnished by C−H borylation strategy. Single‐crystal X‐ray analysis revealed the presence of two conformational enantiomers crystallizing in a racemic mixture. Through their embedded five‐ and seven‐membered rings these polycyclic aromatic hydrocarbons (PAHs) exhibit both negative and positive curvature and UV/Vis/NIR absorption spectroscopy as well as cyclic voltammetry experiments provided insights into the influence of larger flanking aromatic systems and electron‐donating substituents encompassing the heptagonal ring. Through [5+2] annulation of acenaphthylene an azulene‐containing PAH with intriguing optoelectronical properties including a very small bandgap and absorption over the whole visible spectrum could be obtained. Theoretical calculations were employed to elucidate the long‐wavelength absorption and aromaticity. KW - annulation KW - aromaticity KW - azulene KW - Corannulene KW - polycyclic aromatic hydrocarbons Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262627 VL - 2022 IS - 5 ER - TY - THES A1 - Suraru, Sabin-Lucian T1 - Elektronenarme und kernerweiterte Naphthalindiimide und Diketopyrrolopyrrole für organische Dünnschichttransistoren T1 - Electron-deficient and core-extended naphthalene diimides and diketopyrrolopyrroles for organic thin film transistors N2 - Im Rahmen dieser Arbeit wurde gezeigt, dass die elektronischen Eigenschaften und das Packungsverhalten von Naphthalindiimid (NDI)- und Diketopyrrolopyrrol (DPP)- Derivaten durch Einführen geeigneter Substituenten sowie durch Erweiterung des konjugierten Pi-Systems zur Optimierung der Eigenschaften als organische Halbleitermaterialien eingestellt werden können. Während DPP-Halbleiter zwar in Polymeren, nicht jedoch als niedermolekulare Halbleiter, für die organische Elektronik von Bedeutung sind, stellen vor allem die hier vorgestellten cyanierten DPP-Derivate eine synthetisch leicht zugängliche Klasse an niedermolekularen p-Halbleitern mit exzellenten Lochtransporteigenschaften dar. Die Expansion des NDI- und DPP-Kerns eröffnet zudem den synthetischen Zugang zu neuen Verbindungsklassen mit veränderten elektronischen Eigenschaften. Gerade das für die Carbazolocarbazoldiimide postulierte Konzept einer elektronenreichen p-Transportachse konnte durch Wahl geeigneter Imidsubstituenten zur Entwicklung zweidimensionaler p-Halbleiter mit sehr guten Mobilitäten führen. Schließlich stellen 2,6-kernhalogenierte NDI-Derivate mit fluorierten Imidgruppen aufgrund der herausragenden Elektronenmobilitäten und der sehr hohen Luftstabilität außergewöhnliche Kandidaten für den Einsatz als n-Halbleiter in organischen Dünnschichttransistoren dar. N2 - The present thesis shows that the electronic and packing properties of naphthalene diimide (NDI) and diketopyrrolopyrrole (DPP) derivatives can be tuned by introduction of suitable substituents and by the extension of the conjugated pi-core, in order to optimize the properties of the respective organic semiconductor materials. Although DPP derivatives have attracted much attention as structural units in polymers, they have hardly been investigated as small molecule semiconductors in the field of organic electronics. Thus, especially the cyanated DPP derivatives represent a significant step towards easily accessible, high performance p-type molecular material based on DPP. Furthermore, the extension of the aromatic NDI and DPP cores opens up synthetic access to new classes of compounds with modified electronic properties. Especially interesting is the postulated and demonstrated concept for designing carbazolocarbazole diimides with an electron-rich p-axis for charge transport resulting in the development of efficient two-dimensional p-type semiconductors with high mobilities by proper choice of imide substituents. Finally, due their outstanding electron mobilities and very high air stability, the 2,6-core-halogenated NDIs with fluorinated imide substituents are exceptionally promising candidates as n-type semiconductors in organic TFTs. KW - Dünnschichttransistor KW - Organischer Halbleiter KW - Anellierung KW - Naphthalindiimid KW - Diketopyrrolopyrrol KW - thin film transistor KW - organic semiconductor KW - annulation KW - naphthalene diimide KW - diketopyrrolopyrrole Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87880 ER -