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Fluorinated Butatrienes Fluorinated Butatrienes Dissertation zur Erlangung des akademischen Grades des Doktors der Naturwissenschaften (Dr. rer. nat.) eingereicht im Fachbereich Biologie, Chemie, Pharmazie der Freien Universität Berlin vorgelegt von Dipl.-Chem. Christian Ehm aus Berlin Berlin, April 2010 1. Gutachter: Prof. Dr. Dieter Lentz 2. Gutachter: Prof. Dr. Beate Paulus Disputation am 28.6.2010 I Acknowledgements It would not have been possible to write this doctoral thesis without the help and support of the kind people around me, to only some of whom it is possible to give particular mention here. First and foremost I would like to thank my principal supervisor, Professor Dieter Lentz, for the opportunity of doing research in his group. Without his continuous support and encouragement this thesis would not be in the present state. I highly appreciate that Professor Beate Paulus has agreed to be co-referee of my thesis. I would like to cordially thank Lada for her love and patience as well as her interest in my research. Special thanks to my family for their continuous support and love. I would like to thank Mike Roland, Sten Dathe and Sven Wünsche for their friendship and the fun we have had every Sunday evening. Special thanks to Sebastian Freitag, Boris Bolsinger and Frederic Heinrich for their friendship. They deserve much gratefulness for keeping me on the right way. I would like to thank all my colleagues at the Institut für Chemie und Biochemie, Abteilung Anorganische Chemie. In particular I want to thank all members of the Lentz group, Thomas Hügle, Moritz Kühnel, Dr. Floris Akkerman, Dr. Małgorzata Szwak, Dr. Rainer Kickbusch, Bernd Schmitt, Max Römer and Stefanie Fritz for the helpful discussions and funny times. I highly appreciate the careful proof reading of my thesis and publications by Moritz and Thomas. Additionally I would like to thank some ´special´ members of other research groups for their friendship and the funny times we shared: Dr. Meike Roskamp, Denis Petri, Christian Rohner, Christoph Erk, Stephan Meyer, and Birgit Müller. I would like to thank the all the services at the Freie Universität Berlin, the material store (Karl Bohl and Joachim Völter), glass blower (Dirk Busold), mechanic (Peter Scharmberg), accounts department (Daniela Doppelstein), secretariat (Inge Kanakaris-Wirtl and Lamis Sires) and building services (Jürgen-Peter Böttcher) deserve particular credit. They all contributed to the success of this thesis. For a one year scholarship, the Freie Universität Berlin is highly acknowledged just as well I have to thank Professor Peter Luger for giving me a one year salaried position and the II opportunity to teach mathematics. Special thanks to my lab colleague Stefanie Fritz. I am very grateful for her outstanding friendship and guidance. She has always been a source of inspiration during the last four years. Furthermore I appreciate the careful proof-reading of my thesis and publications. Her sense of humor brightened up the darkest days. III List of Publications Articles in Journals: • Christian Ehm, Dieter Lentz (2010) “Partially Fluorinated Butatrienes: A Coupled Cluster Study” J. Phys. Chem. A 2010, 114, 3609-3614. • Christian Ehm, Dieter Lentz (2010) “Diels-Alder Reactions of 1,1,4,4- Tetrafluorobutatriene” Chem. Commun. 2010, 46, 2399-2401. • Christian Ehm, Floris A. Ackerman, Dieter Lentz (2010) “Fluorinated Butatrienes”, J. Fluor. Chem. 2010, DOI:10.1016/j.jfluchem.2010.06.017. • Christian Ehm, Dieter Lentz (2010) “Cyclic Dimers of Tetrafluorobutatriene” Org. Biomol. Chem., submitted. Poster contributions: “First metal free variant of the Stille-type cross-coupling reaction” 18th International Symposium on Fluorine Chemistry Prag, 2006 Lectures: “Fluorierte Kumulene: Butatriene” 13. Deutscher Fluortag, Schmitten/Dorfweil 2008 IV Table of Content 1 Introduction...............................................................................................................1 2 Results and Discussion............................................................................................7 2.1 Aims of this work...............................................................................................7 2.2 Tetrafluorobutatriene.........................................................................................8 2.2.1 Improved Synthesis of Tetrafluorobutatriene.............................................8 2.2.2 Organic Reactions Involving Tetrafluorobutatriene..................................12 2.2.2.1 Diels – Alder Reactions....................................................................12 2.2.2.2 Other Pericyclic Reactions...............................................................19 2.3 Dimers and Higher Oligomers of Tetrafluorobutatriene..................................21 2.3.1 Tetrafluorobutatriene – Dimers................................................................21 2.3.2 Higher Oligomers of Tetrafluorobutatriene – Some Comments on the Constitution of the Tetrafluorobutatriene Polymer........................38 2.4 Partially Fluorinated Butatrienes.....................................................................40 2.4.1 Partially Fluorinated Butatrienes and their Enyne Isomers – Theoretical Considerations......................................................................40 2.4.1.1 State of the Art....................................................................................40 2.4.1.2 C4H3F................................................................................................43 2.4.1.3 C4H2F2...............................................................................................45 2.4.1.4 C4HF3................................................................................................49 2.4.1.5 C4H4 and C4F4...................................................................................51 2.4.1.6 Isodesmic Reactions – Stabilization or Destabilization of Tetrafluorobutatriene by Fluorination?..............................................52 2.4.1.7 Conclusions......................................................................................53 2.4.2 Partially Fluorinated Butatrienes – Synthetic Strategies.........................55 2.4.2.1 Synthetic Strategies for the Synthesis of Butatrienes........................55 2.4.2.1 Attempted Synthesis of 1,1-Difluorobutatriene by Multiple Hydrogen Fluoride Elimination from 1,1,1,3,3-Pentafluorobutane...56 2.4.2.2 Attempted Synthesis of 1,1-Difluorobutatriene by Rearrangement Reactions of 1,1-Difluorobuta-1-en-3-yne .......................................58 2.4.2.3 Attempted Synthesis of 1,1-Difluorobutatriene by Elimination of Hydrogen Bromide from Suitable Precursors...............................59 2.4.2.4 Attempted Synthetic Approaches to Potential Precursors of 1,1-Difluorobutatriene ..................................................................64 2.4.2.5 Elimination of Hydrogen Halides to Form Cumulenic Centers – Theoretical Considerations...............................................................67 2.4.2.6 Comments on the Synthesis of Small Fluorinated Molecules by Coupling Reactions Involving Fluorinated Ethylene or Methane Building Blocks ................................................................................69 2.4.2.7 Attempted Synthesis of 1,1-Difluorobut-1-en-3-yne Metal Complexes – Potential Precursors for 1,1-Difluorobutatriene Metal Complexes..............................................................................71 2.4.2.8 Conclusions......................................................................................72 2.5 Higher Homologues of Tetrafluorobutatriene – Tetrafluorinated Pentatetraene and Hexapentaene....................................73 2.6 Attempted Syntheses of Tetrafluorobutatriene Transition Metal Complexes – Considerations on the Instability of Tetrafluorobutatriene....77 3 Summary and Outlook............................................................................................81 4 Theoretical Background..........................................................................................83 V 4.1 Introduction......................................................................................................83 4.2 Electronic Structure Methods..........................................................................85 4.2.1 Self-consistent Field Theory....................................................................85 4.2.2 The Energy of a Slater Determinant........................................................87 4.2.3 The Basis Set Approximation...................................................................93 4.3 Electron Correlation Methods.........................................................................95 4.3.1 Introduction..............................................................................................95 4.3.2 Excited Slater determinants.....................................................................96 4.3.3 Configuration Interaction..........................................................................97 4.3.4 Size Consistency and Size Extensivity..................................................101 4.3.5 Many Body Pertubation Theory.............................................................101 4.3.6 Coupled Cluster Methods......................................................................108 4.3.7 Connections between Coupled Cluster, Configuration Interaction and Perturbation Theory.........................................................................111 4.4 Basis Sets......................................................................................................113
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