Stimuli-Responsive Self-Assembly and Spatial Functionalization of Organic Cages Based on Tribenzotriquinacenes Dissertation zur Erlangung des naturwissenschaftlichen Doktorgrades der Julius-Maximilians-Universität Würzburg vorgelegt von Ayan Dhara aus Singarkone, Indien   Würzburg 2017 Eingereicht bei der Fakultät für Chemie und Pharmazie am: __11_._0_9_.2_0_1_7___________ Gutachter der schriftlichen Arbeit: 1. Gutachter: Priv.-Doz. Dr. Florian Beuerle 2. Gutachter: Prof. Dr. Frank Würthner Prüfer des öffentlichen Promotionskolloquiums: 1. Prüfer: Priv.-Doz. Dr. Florian Beuerle 2. Prüfer: Prof. Dr. Frank Würthner 3. Prüfer: Prof. Dr. Udo Radius Datum des öffentlichen Promotionskolloquiums: _2_7_._10_._2_0_17____________ Doktorurkunde ausgehändigt am: ____________________ i ii Dedicated To My beloved Parents iii iv List of Abbreviations BARF Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate BET Brunauer-Emmett-Teller CCDC Cambridge Crystallographic Data Center COF Covalent Organic Framework CTV Cyclotriveratrylene D Diffusion Coefficient DABCO 1,4-Diazabicyclo[2.2.2]octane DCC Dynamic Covalent Chemistry DCM Dichloromethane DCTB trans-2-[3-(4-tert-Butylphenyl)-2-methyl-2-propenylidene]malononitrile DIBAL-H Di-iso-butylaluminium hydride DMSO Dimethylsulfoxide DOSY Diffusion-Ordered Spectroscopy EA Elemental Analysis EM Effective Molarity G Gibbs Free Energy H Enthalpy ITC Isothermal Titration Calorimetry K Association Constant a k Boltzmann Constant B K Intrinsic Binding Constant i K Statistical Factor σ MALDI Matrix-Assisted Laser Desorption/Ionization MOF Metal Organic Framework MOMCl Methoxymethyl chloride MS Mass Spectrometry N Avogadro constant A NBS N-Bromosuccinimide v NMR Nuclear Magnetic Resonance OAc Acetoxy OMIM Organic Monomer with Intrinsic Microporosity ORTEP Oak Ridge Thermal Ellipsoid Plot OTf Trifluoromethanesulfonate PIM Polymer with Intrinsic Microporosity PM6 Parameterization Method 6 ppm Parts Per Million p-TsOH para-Toluenesulfonic acid Q Heat Change R Gas Constant r Radius R Retention factor f rt Room Temperature S Entropy TBAF Tetra-n-butylammonium fluoride TBTQ Tribenzotriquinacene TES Triethylsilyl TFA Trifluoroacetic acid THC Tetrahedral Character THF Tetrahydrofuran TLC Thin Layer Chromatography TMS Trimethylsilyl TOF Time of flight tpt 2,4,6-Tri(4-pyridyl)-1,3,5-triazine η Viscosity ρ Density σ Symmetry Number σ External Symmetry Number ext σ Internal Symmetry Number int vi Table of Contents     Chapter 1 - Aim of the Thesis ........................................................... 1   Chapter 2 - Literature Survey .......................................................... 5   2.1 Boron-Nitrogen Dative Bonds in Supramolecular Assemblies .................................... 5  2.1.1 Geometry and Stability of Boron-Nitrogen Dative Bonds ..................................... 7  2.1.2 Boron-Nitrogen Dative Bonds as Secondary Interactions .................................... 10  2.1.3 Boron-Nitrogen Dative Bonds as Primary Interactions ........................................ 13  2.2 Tribenzotriquinacene ................................................................................................... 19  2.2.1 Structural Analysis ............................................................................................... 21  2.2.2 Synthesis of the TBTQ Scaffold ........................................................................... 21  2.2.3 Bridgehead-Functionalization .............................................................................. 23  2.2.4 Outer rim-Functionalization ................................................................................. 27  2.2.5 Ortho-Functionalization ....................................................................................... 30  2.2.6 Apical-Functionalization ...................................................................................... 31  2.3 Framework Materials .................................................................................................. 33  2.3.1 Covalent Organic Cage Compounds .................................................................... 34  2.3.2 Endohedral Functionalization of Covalent Organic Cage Compounds ............... 36  2.3.3 Exohedral Functionalization of Covalent Organic Cage Compounds.................. 38  Chapter 3 - Results and Discussion ................................................ 40   3.1 An Organic Cage Linked by Boron-Nitrogen Dative Bonds ...................................... 40  3.1.1 Design Principle ................................................................................................... 40  3.1.2 Model System ....................................................................................................... 42  3.1.3 Supramolecular Cage Based on Boron-Nitrogen Dative Bonds .......................... 46  3.1.4 Stimuli-Responsive Switching ............................................................................. 55  3.2 Apical Functionalization of Tribenzotriquinacene ...................................................... 59  3.2.1 Design Principles .................................................................................................. 60  3.2.2 Synthesis of Apically Functionalized Tribenzotriquinacene ................................ 62  3.2.3 Deprotection of Methoxy Groups ......................................................................... 67  3.2.4 Apically Functionalized Tribenzotriquinacenes ................................................... 68  vii 3.3 Functionalized Organic Cages .................................................................................... 72  3.3.1 Exohedral Cage Functionalization ....................................................................... 72  3.3.2 Synthesis of a 2-Substituted-meta-diboronic Acid .............................................. 76  3.3.3 Towards the Formation of Cages Possessing Both Interior and Exterior Functionalities ............................................................................................................... 82  Chapter 4 - Summary ...................................................................... 86   Chapter 5 - Zusammenfassung ....................................................... 90   Chapter 6 - Experimental Section .................................................. 95   6.1 Materials and Methods ............................................................................................... 95  6.2 Synthesis and Characterization ................................................................................... 96  References ....................................................................................... 111   Appendix ......................................................................................... 120   Crystallographic Data ..................................................................................................... 120  Analytical Data ............................................................................................................... 123  Titration Data .................................................................................................................. 145  1H-NMR Spectroscopy ............................................................................................... 145  Isothermal Titration Calorimetry (ITC) ...................................................................... 147  Acknowledgements ........................................................................ 149       viii