Synthese von funktionellen Buckybowls und verwandten Nanostrukturen über die regioselektive Zyklodehydrofluorierung

The main goal of this thesis was the synthesis of the extended PAHs via selective C-F bond activation. The first part of the thesis is concentrated on the activation of C-F bond in the trifluoromethyl group in the aromatic arenes under mild conditions. We found out that the direct intramolecular cyclization of the CF3 group on activated alumina allows us to synthesize a range of the cyclic aromatic ketones in appropriate yields. The main advantages of this approach are the scalability, the inexpensive starting materials, the high tolerance of the CF3 group and the high selectivity of reaction. In addition, the hydrolysis of the CF3 group was found to be a simple way for the synthesis of carboxylated PAHs. Furthemore, we demonstrate a facile pathway for synthesis have presented an approach for the synthesis of rationally halogenated bowl-shaped PAHs. We succeeded in the transformation of precursors into the halogenated buckybowls by aryl-aryl coupling in near-quantitative yields. The presented method allowed us to introduce the halogen functionalities at virtually any position and, thus, the obtained halogenated diindenochrysenes and indacenopicenes can be used as building blocks for structures with the complex architecture. The alumina promoted aryl-aryl coupling appeared to be tolerant towards aromatic C-Br and C-Cl bonds. For the first time, the X-ray crystallographic analysis of diindeno[4,3,2,1-cdef:4',3',2',1'-lmno]chrysene structure was conducted and the bowl-shaped character of the molecule was confirmed (bowl depth at 1.78 Å). It is worth to mention that in the alumina-promoted aromatic C-F bond activation a solvent plays a crucial role providing the homogenious distribution of the precursor and influencing the efficiency of HF-elimination. Our finding revealed the ability of o-dichlorobenzene to accelerate the reaction up to 200 times yielding a pure target compound. In the second part of the thesis we present a novel type of molecular receptor based on two indacenopicene units and tolyl as a tether. The binding behaviour of the 9,9'-(5-methyl-1,3-phenylene)di-as-indaceno[3,2,1,8,7,6-pqrstuv]picene towards C60 or C70 in toluene was investigated by fluorescence spectroscopy. The formation of 1:1 complexe in the presence of C60 or C70 was herewith confirmed. Titration experiments gave crude estimation of the association constants. The preliminary association constants were found to be 8.65×103 M-1 for C60 and 6.04×104 M-1 for C70 complexes. Thus, the binding affinity to C70 is significantly higher than to C60. The third part of the thesis describes the synthetic approach for the preparation of the highly curved buckybowls from the diindenochrysene precursor. The product obtained by the double-fold Suzuki cross-coupling and subsequent aryl-aryl coupling on the activated alumina exhibits the large bowl depth (5.2 Å). Moreover, in this chapter we illustrated a pyrene-based method for the synthesis of oligoindenopyrenes including the intramolecular cyclization via C-F bond activation. The last part of the thesis highlights the introduction of peripheral zig-zag units into nanographene molecules by acid-promoted intramolecular reductive cyclization. As precursor for acene-type nanographenes were employed aromatic aldehydes. The advantages of such cycloaromatization are effectiveness, availiability of chemicals, scalability and near-quantitative yields. The developed reaction protocol allowed us to synthesize a series of nanographenes and the bowl-shaped acene-type molecule based on diindenochrysene core. Taken together, these findings suggested the simple and facile ways towards extended bowl-shaped and planar structures, which can be utilized in the synthesis of fullerenes, nanotubes and nanographenes.Das Hauptziel der Dissertation war die Synthese von erweiterten polyzyklischen aromatischen Kohlenwasserstoffen durch die selektive C-F-Bindungsaktivierung. Der erste Teil der Arbeit konzentriert sich auf die Aktivierung der C-F-Bindung in der Trifluormethylgruppe in den aromatischen Arenen unter milden Bedingungen. Wir fanden heraus, dass die direkte intramolekulare Zyklisierung der CF3-Gruppe auf aktiviertem Aluminiumoxid es uns ermöglicht, eine Reihe der zyklischen aromatischen Ketone in geeigneten Ausbeuten zu synthetisieren. Die Hauptvorteile dieses Ansatzes sind die Skalierbarkeit, die kostengünstigen Ausgangsstoffe, die hohe Toleranz der CF3-Gruppe und die hohe Selektivität der Reaktion. Darüber hinaus wurde festgestellt, dass die Hydrolyse der CF3-Gruppe ein einfacher Weg für die Synthese von carboxylierten PAK ist. Des Weiteren erarbeiteten wir eine einfache Methode zur Synthese und haben einen Ansatz für die Synthese von rational halogenierten schalenförmigen PAKs vorgestellt. Es ist uns in nahezu quantitativen Ausbeuten gelungen, die Präkursore in halogenierte Buckybowls durch Aryl-Aryl-Kupplung zu transformieren. Die vorgestellte Methode erlaubt es uns, die Halogenfunktionalitäten an beliebiger Stelle einzuführen. Somit können die syntetisierten halogenierten Diindenochrysene und Indacenopene als Bausteine für Strukturen mit einer komplexen Architektur verwendet werden. Die mit Aluminiumoxid geförderte Aryl-Aryl-Kupplung schien tolerant gegenüber aromatischen C-Br- und C-Cl-Bindungen zu sein. Erstmals wurde die röntgenkristallographische Analyse der Diindenochrysenstruktur durchgeführt und der schalenförmige Charakter des Moleküls bestätigt (Schalentiefe von 1.78 Å). Es gilt zu erwähnen, dass bei der durch Aluminiumoxid produzierten aromatischen C-F-Bindungsaktivierung das Lösungsmittel eine entscheidende Rolle spielt. Es sorgt für eine homogene Verteilung des Präkursors und beeinflusst die Effizienz der HF-Eliminierung. Unser Ergebnis zeigte die Fähigkeit von o-Dichlorbenzol, die Reaktion bis zu 200-mal zu beschleunigen, was zu einer reinen Zielverbindung führt. Im zweiten Teil der Arbeit präsentieren wir einen neuartigen Typ eines molekularen Rezeptors, der auf zwei Indacenopicen-Einheiten und Phenyl als Halteverbindung basiert. Das Bindungsverhalten des 9,9'-(5-Methyl-1,3-phenylen)di-as-indace-no[3,2,1,8,7,6-pqrstuv]picens gegenüber C60 oder C70 in Toluol wurde mithilfe von Fluoreszenzspektroskopie untersucht. Die Bildung eines 1:1-Komplexes in Anwesenheit von C60 oder C70 wurde hiermit bestätigt. Die Titrationsexperimente gaben eine grobe Einschätzung der Assoziationskonstanten. Die vorläufige Assoziationskonstanten wurden als 8,65×103 M-1 für C60 und 6,04×104 M-1 für C70-Komplexe definiert. Somit ist die Bindungsaffinität zu C70 deutlich höher als zu C60. Das dritte Kapitel beschreibt einen synthetischen Ansatz für die Herstellung der stark gewölbten Buckybowls aus Diindenochrysen-Präkursoren. Das durch die doppelte Suzuki-Kreuzkupplung und die anschließende Aryl-Aryl-Kupplung auf aktiviertem Aluminiumoxid erhaltene Produkt weist eine sehr große Schalentiefe (5.2 Å) auf. Darüber hinaus veranschaulichen wir in diesem Teil ein pyrenbasiertes Verfahren zur Synthese von Oligoindenopyrenen einschließlich der intramolekularen Zyklisierung über die C-F-Bindungsaktivierung. Das letzte Kapitel dieser Dissertation widmet sich der Einführung von dezentralen Zickzack-Einheiten in Nanographene-Moleküle mittels säurefördernder intramolekularer reduktiver Zyklisierung. Als Präkursor für die acenartigen Nanographene wurden aromatische Aldehyde eingesetzt. Die Vorteile einer solchen Zykloaromatisierung sind die Effektivität, die gute Verfügbarkeit der Chemikalien, die gute Skalierbarkeit, sowie nahezu quantitative Ausbeuten. Die von uns entwickelte Synthesestrategie erlaubte es, eine Reihe von Nanographenen und das schalenförmige acenartige diindenochrysenbasierte Molekül herzustellen. Zusammengefasst, zeigen diese Ergebnisse einen einfachen und leichten Wege zu erweiterten schalenförmigen und planaren Strukturen auf, die zur Synthese von Fullerenen, Nanoröhren und Nanographenen genutzt werden können

An Indacenopicene‐based Buckybowl Catcher for Recognition of Fullerenes

A novel buckybowl catcher with an extended π-surface has been synthesized via cross-coupling of two bowl shaped bromoindacenopicene moieties with a tolyl linker. The obtained catcher has been unambiguously characterized by 2D-NMR and mass spectrometry. DFT calculations indicate that the curved shape of the receptor moieties is favourable for binding fullerenes. Effective binding was confirmed for interactions with C$_{60}$ and C$_{70}$ utilizing NMR spectroscopy and isothermal titration calorimetry (ITC). The resulting binding values show a higher affinity of the catcher towards C$_{70}$ over C$_{60}$. The designed catcher demonstrated the fundamental possibility of creating sensors for spherical aromaticity

Design and Synthesis of Pyrido[2,1‑<i>b</i>][1,3,5]thiadiazine Library via Uncatalyzed Mannich-Type Reaction

This Research Article describes the synthesis of an over 700-member library of (8<i>R</i>/8<i>S</i>)-3-R-8-aryl-6-oxo-3,4,7,8-tetrahydro-2<i>H</i>,6<i>H</i>-pyrido­[2,1-<i>b</i>]­[1,3,5]­thiadiazin-9-carbonitriles by uncatalyzed Mannich-type reaction of <i>N</i>-methylmorpholinium (4<i>R</i>/4<i>S</i>)-4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridin-2-thiolates with a set of primary amines and excessive HCHO. The scope and limitations of the reaction were studied. Starting thiolates were obtained in yields of 53–82% by multicomponent reaction of aromatic aldehydes, cyanothioacetamide, 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum’s acid), and <i>N</i>-methylmorpholine, followed by heterocyclization of the resulting Michael adducts

From Corannulene to Indacenopicene: Effect of Carbon Framework Topology on Aromaticity and Reduction Limits

The electronic structure, reduction limits, and coordination abilities of a bowl-shaped polycyclic aromatic hydrocarbon, indacenopicene (C₂₆H₁₂, <b>1</b>), have been investigated for the first time using a combination of theoretical and experimental tools. A direct comparison with the prototypical corannulene bowl (C₂₀H₁₀, <b>2</b>) revealed the effects of carbon framework topology and symmetry change on the electronic properties and aromaticity of indacenopicene. The accessibility of two reduction steps for <b>1</b> was predicted theoretically and then confirmed experimentally. Two reversible one-electron reduction processes with the formal reduction potentials at −1.92 and −2.29 V vs Fc^+/0 were detected by cyclic voltammetry measurements, demonstrating the stability of the corresponding mono- and dianionic states of <b>1</b>. The products of the doubly reduced indacenopicene have been isolated as rubidium and cesium salts and fully characterized. Their X-ray diffraction study revealed the formation of tetranuclear organometallic building blocks with the [M₂(18-crown-6)]²⁺ (M = Rb (<b>3</b>) and Cs (<b>4</b>)) cations occupying the concave cavities of two C₂₆H₁₂^2– anions. The coordination of two outside <i>exo</i>-bound rubidium ions is terminated by crown ether molecules in <b>3</b> to form the discrete [Rb⁺₄(18-crown-6)₃­(C₂₆H₁₂^2–)₂] tetramer. In contrast, the larger cesium ions allow the 1D polymeric chain propagation in <b>4</b> to afford [Cs⁺₂(18-crown-6)₂­(THF)­(C₂₆H₁₂^2–)]_∞

From Corannulene to Indacenopicene: Effect of Carbon Framework Topology on Aromaticity and Reduction Limits

The electronic structure, reduction limits, and coordination abilities of a bowl-shaped polycyclic aromatic hydrocarbon, indacenopicene (C₂₆H₁₂, <b>1</b>), have been investigated for the first time using a combination of theoretical and experimental tools. A direct comparison with the prototypical corannulene bowl (C₂₀H₁₀, <b>2</b>) revealed the effects of carbon framework topology and symmetry change on the electronic properties and aromaticity of indacenopicene. The accessibility of two reduction steps for <b>1</b> was predicted theoretically and then confirmed experimentally. Two reversible one-electron reduction processes with the formal reduction potentials at −1.92 and −2.29 V vs Fc^+/0 were detected by cyclic voltammetry measurements, demonstrating the stability of the corresponding mono- and dianionic states of <b>1</b>. The products of the doubly reduced indacenopicene have been isolated as rubidium and cesium salts and fully characterized. Their X-ray diffraction study revealed the formation of tetranuclear organometallic building blocks with the [M₂(18-crown-6)]²⁺ (M = Rb (<b>3</b>) and Cs (<b>4</b>)) cations occupying the concave cavities of two C₂₆H₁₂^2– anions. The coordination of two outside <i>exo</i>-bound rubidium ions is terminated by crown ether molecules in <b>3</b> to form the discrete [Rb⁺₄(18-crown-6)₃­(C₂₆H₁₂^2–)₂] tetramer. In contrast, the larger cesium ions allow the 1D polymeric chain propagation in <b>4</b> to afford [Cs⁺₂(18-crown-6)₂­(THF)­(C₂₆H₁₂^2–)]_∞

From Corannulene to Indacenopicene: Effect of Carbon Framework Topology on Aromaticity and Reduction Limits

The electronic structure, reduction limits, and coordination abilities of a bowl-shaped polycyclic aromatic hydrocarbon, indacenopicene (C₂₆H₁₂, <b>1</b>), have been investigated for the first time using a combination of theoretical and experimental tools. A direct comparison with the prototypical corannulene bowl (C₂₀H₁₀, <b>2</b>) revealed the effects of carbon framework topology and symmetry change on the electronic properties and aromaticity of indacenopicene. The accessibility of two reduction steps for <b>1</b> was predicted theoretically and then confirmed experimentally. Two reversible one-electron reduction processes with the formal reduction potentials at −1.92 and −2.29 V vs Fc^+/0 were detected by cyclic voltammetry measurements, demonstrating the stability of the corresponding mono- and dianionic states of <b>1</b>. The products of the doubly reduced indacenopicene have been isolated as rubidium and cesium salts and fully characterized. Their X-ray diffraction study revealed the formation of tetranuclear organometallic building blocks with the [M₂(18-crown-6)]²⁺ (M = Rb (<b>3</b>) and Cs (<b>4</b>)) cations occupying the concave cavities of two C₂₆H₁₂^2– anions. The coordination of two outside <i>exo</i>-bound rubidium ions is terminated by crown ether molecules in <b>3</b> to form the discrete [Rb⁺₄(18-crown-6)₃­(C₂₆H₁₂^2–)₂] tetramer. In contrast, the larger cesium ions allow the 1D polymeric chain propagation in <b>4</b> to afford [Cs⁺₂(18-crown-6)₂­(THF)­(C₂₆H₁₂^2–)]_∞