Metal-mediated perfluoroalkylations and the electrochemical fluorination to perfluoroalkyl compounds

Diese Arbeit beschäftigt sich mit der Synthese und Charakterisierung von mehrfach perfluoralkylierten Verbindungen. Das erste Kapitel behandelt die Kupfer-vermittelte mehrfache Pentafluorethylierung von aromatischen Systemen, sowie die Untersuchung deren Folgechemie. Dabei wurden iodierte Aryl-Derivate mit dem Kupferorganyl CuC2F5 umgesetzt. Mit dieser Methode konnten symmetrisch und unsymmetrisch pentafluorethylierte Anilin- und Phenol-Derivate dargestellt werden. Die Anilin-Derivate wurden zu den entsprechenden Diazoniumsalzen umgesetzt, welche zunächst vollständig charakterisiert und anschließend deren Folgechemie untersucht wurde. Das zweite Kapitel behandelt die Darstellung von Bis(trifluormethyl)sulfon durch elektrochemische Fluorierung mittels des Simons-Prozesses. Dabei wurde der Umsatz der Reaktion durch Verwendung der teilfluorierten Verbindung (Trifluormethyl)methylsulfon als Startmaterial optimiert.Within this thesis multiple perfluoroalkylated compounds were synthesized and characterized. The first chapter deals with the copper-mediated multiple pentafluoroethylation of aromatic systems, and the investigation of their further reactivity. In this work, iodinated aryl derivatives were reacted with the copper organyl CuC2F5. Symmetrically and asymmetrically pentafluoroethylated aniline and phenol derivatives were prepared via this method. The aniline derivatives were reacted to give the corresponding diazonium salts, which were first fully characterized and then their further reactivities were investigated. The second chapter deals with the preparation of bis(trifluoromethyl)sulfone by electrochemical fluorination using the Simons process. Here, the conversion of the reaction was optimized by using the partially fluorinated compound (trifluoromethyl)methyl sulfone as starting material

The crystal structure of trimethylsulfonium tris(trifluoromethylsulfonyl)methanide, C7_7H9_9F9_9O6_6S4_4

C$_7$H$_9$F$_9$O$_6$S$_4$, orthorhombic, P2$_1$2$_1$2$_1$ (no. 19), a = 8.80180(10) Å, b= 10.96580(10) Å, c = 16.91360(10) Å,V= 1632.48(3) Å$^3$, Z= 4, R$_{gt}$(F) = 0.0222, wR$_{ref}$(F$^2$) = 0.0604, T = 100 K

Pentafluoroethylaluminates: A Combined Synthetic, Spectroscopic, and Structural Study

Salts of the tetrakis(pentafluoroethyl)aluminate anion [Al(C$_{2}$F$_{5}$)$_{2}$]$^{-}$ were obtained from AlCl$_{3}$ and LiC$_{2}$F$_{5}$. They were isolated with different counter‐cations and characterized by NMR and vibrational spectroscopy and mass spectrometry. Degradation of the [Al(C$_{2}$F$_{5}$)$_{4}$]$^{-}$ ion was found to proceed via 1,2‐fluorine shifts and stepwise loss of CF(CF$_{3}$) under formation of [(C$_{2}$F$_{5}$)$_{4-n}$AlF$_{n}$]− (n=1–4) as assessed by NMR spectroscopy and mass spectrometry and supported by results of DFT calculations. In addition, the [(C$_{2}$F$_{5}$)AlF$_{3}$]$^{-}$ ion was structurally characterized

Innovative Syntheses of Cyano(fluoro)borates: Catalytic Cyanation, Electrochemical and Electrophilic Fluorination

Different types of high‐yield, easily scalable syntheses for cyano(fluoro)borates Kt[BF$_{n}$(CN)$_{4-n}$] (n=0–2) (Kt=cation), which are versatile building blocks for materials applications and chemical synthesis, have been developed. Tetrafluoroborates react with trimethylsilyl cyanide in the presence of metal‐free Brønsted or Lewis acid catalysts under unprecedentedly mild conditions to give tricyanofluoroborates or tetracyanoborates. Analogously, pentafluoroethyltrifluoroborates are converted into pentafluoroethyltricyanoborates. Boron trifluoride etherate, alkali metal salts, and trimethylsilyl cyanide selectively yield dicyanodifluoroborates or tricyanofluoroborates. Fluorination of cyanohydridoborates is the third reaction type that includes direct fluorination with, for example, elemental fluorine, stepwise halogenation/fluorination reactions, and electrochemical fluorination (ECF) according to the Simons process. In addition, fluorination of [BH(CN)$_{2}${OC(O)Et}]$^{-}$ to result in [BF(CN)$_{2}${OC(O)Et}]$^{-}$ is described

cAAC‐stabilisierte 9,10‐Diboraanthracene – offenschalige Singulettbiradikale

Geringe HOMO-LUMO-Abstände und eine hohe Ladungsträgermobilität prädestinieren die höheren Acene für Anwendungen im Bereich der Organoelektronik. Die Leistungsfähigkeit derartiger Verbindungen steigt hierbei dramatisch mit der Anzahl anellierter Benzolringe. Größere Acenmengen sind synthetisch bisher jedoch nur für Acene bis Heptacen verlässlich zugänglich. Theoretischen Studien zufolge besitzen (Oligo)acene offenschalige Singulettbiradikal- und (Poly)acene polyradikalische Grundzustände. Eindeutige experimentelle Belege für diese Vorhersagen sind hingegen äußerst selten. Durch den Einbau von zwei Boratomen in das Anthracengrundgerüst konnten wir den HOMO-LUMO-Abstand von Acenen dramatisch verringern und zwar ohne die Notwendigkeit einer Ausweitung des konjugierten π-Systems. Stabilisierung der Borzentren durch cyclische (Alkyl)(amino)carbene lieferte hierbei neutrale 9,10-Diboraanthracene mit disjunkten, offenschaligen Singulettbiradikal-Grundzuständen

cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States

Narrow HOMO–LUMO gaps and high charge‐carrier mobilities make larger acenes potentially high‐efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open‐shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO–LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10‐diboraanthracenes, which are shown to feature disjointed, open‐shell singlet biradical ground states

Innovative Syntheses of Cyano(fluoro)borates: Catalytic Cyanation, Electrochemical and Electrophilic Fluorination

Different types of high‐yield, easily scalable syntheses for cyano(fluoro)borates Kt[BF$_{n}$(CN)$_{4-n}$] (n=0–2) (Kt=cation), which are versatile building blocks for materials applications and chemical synthesis, have been developed. Tetrafluoroborates react with trimethylsilyl cyanide in the presence of metal‐free Brønsted or Lewis acid catalysts under unprecedentedly mild conditions to give tricyanofluoroborates or tetracyanoborates. Analogously, pentafluoroethyltrifluoroborates are converted into pentafluoroethyltricyanoborates. Boron trifluoride etherate, alkali metal salts, and trimethylsilyl cyanide selectively yield dicyanodifluoroborates or tricyanofluoroborates. Fluorination of cyanohydridoborates is the third reaction type that includes direct fluorination with, for example, elemental fluorine, stepwise halogenation/fluorination reactions, and electrochemical fluorination (ECF) according to the Simons process. In addition, fluorination of [BH(CN)$_{2}${OC(O)Et}]$^{-}$ to result in [BF(CN)$_{2}${OC(O)Et}]$^{-}$ is described

cAAC‐Stabilized 9,10‐diboraanthracenes—Acenes with Open‐Shell Singlet Biradical Ground States

Narrow HOMO–LUMO gaps and high charge‐carrier mobilities make larger acenes potentially high‐efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open‐shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO–LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10‐diboraanthracenes, which are shown to feature disjointed, open‐shell singlet biradical ground states

cAAC‐stabilisierte 9,10‐Diboraanthracene – offenschalige Singulettbiradikale

Geringe HOMO-LUMO-Abstände und eine hohe Ladungsträgermobilität prädestinieren die höheren Acene für Anwendungen im Bereich der Organoelektronik. Die Leistungsfähigkeit derartiger Verbindungen steigt hierbei dramatisch mit der Anzahl anellierter Benzolringe. Größere Acenmengen sind synthetisch bisher jedoch nur für Acene bis Heptacen verlässlich zugänglich. Theoretischen Studien zufolge besitzen (Oligo)acene offenschalige Singulettbiradikal- und (Poly)acene polyradikalische Grundzustände. Eindeutige experimentelle Belege für diese Vorhersagen sind hingegen äußerst selten. Durch den Einbau von zwei Boratomen in das Anthracengrundgerüst konnten wir den HOMO-LUMO-Abstand von Acenen dramatisch verringern und zwar ohne die Notwendigkeit einer Ausweitung des konjugierten π-Systems. Stabilisierung der Borzentren durch cyclische (Alkyl)(amino)carbene lieferte hierbei neutrale 9,10-Diboraanthracene mit disjunkten, offenschaligen Singulettbiradikal-Grundzuständen