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Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy University of Bath PHD Stoichiometric and catalytic reactions of ruthenium multi N-heterocyclic carbene complexes Cybulski, Mateusz Award date: 2018 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 24. Sep. 2021 STOICHIOMETRIC AND CATALYTIC REACTIONS OF RUTHENIUM MULTI N-HETEROCYCLIC CARBENE COMPLEXES Mateusz Krzysztof Cybulski A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy University of Bath Department of Chemistry September 2017 Attention is drawn to the fact that copyright of this thesis rests with its author. This copy of this thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and they must not copy it or use material from it except as permitted by law or with the consent of the author. This thesis may be made available for consultation within the University Library and may be photocopied or lent to other libraries for the purposes of consultation. Signed………………………………. Date………………………………. Contents CONTENTS ACKNOWLEDGEMENTS ............................................................................................... i ABSTRACT ...................................................................................................................... ii ABBREVIATIONS ......................................................................................................... iv Analytical .................................................................................................................. iv Units ........................................................................................................................... v Chemical .................................................................................................................... v Chapter 1: Introduction 1.1. C-F bonds and applications of organofluorine compounds .................................. 1 1.2. Fluorine incorporation ........................................................................................... 2 1.3. Catalytic HDF by late transition metal complexes ................................................ 7 1.3.1. Group 8: Iron and ruthenium ...................................................................... 7 1.3.2. Group 9: Cobalt, rhodium and iridium ...................................................... 10 1.3.3. Group 10: Nickel, palladium and platinum ............................................... 20 1.3.4. Group 11: Copper and gold ....................................................................... 26 1.3.5. Heterodimetallic systems .......................................................................... 29 1.4. Ruthenium N-heterocyclic carbene dihydride complexes................................... 31 1.5. Thesis synopsis .................................................................................................... 36 1.6. References for Chapter 1 ..................................................................................... 36 Chapter 2: C-F bond activation using trans-[Ru(NHC)4H2] complexes 2.1. Synthesis of trans-[Ru(NHC)4H2] complexes ..................................................... 41 2.2. Stoichiometric C-F activation of fluoroarenes and synthesis of trans- [Ru(NHC)4HF] complexes................................................................................ 44 2.3. Catalytic HDF of fluoroarenes using trans-[Ru(NHC)4H2] complexes .............. 49 2.4. Mechanistic studies of catalytic HDF ................................................................. 54 Contents 2.4.1. Reactivity of trans-[Ru(IMe)4HF] (4) with silanes ................................... 54 2.4.2. Probing NHC dissociation in catalytic C-F activation .............................. 57 2.4.3. DFT study of catalytic HDF ...................................................................... 65 2.5. Summary ............................................................................................................. 69 2.6. References for Chapter 2 ..................................................................................... 70 Chapter 3: C-F bond activation using [Ru(NHC)2L2H2] complexes 3.1. Introduction ......................................................................................................... 73 3.2. Stoichiometric C-F and C-H activation of C6F6 and C6F5H using [Ru(IEt2Me2)2(PPh3)2H2] (cct-8) ...................................................................... 74 3.2.1. Isolation and characterisation of [Ru(IEt2Me2)2(PPh3)HF] (cct-10) and [Ru(IEt2Me2)2(PPh3)2H][H2F3] (13) ........................................................................ 76 3.2.2. Isolation and characterisation of [Ru(IEt2Me2)2(PPh3)(C6F5)H] (11) ....... 81 3.2.3. Isolation and characterisation of [Ru(IEt2Me2)(PPh3)2(C6F5)H] (12) ....... 83 3.3. Stoichiometric C-F and C-H activation of C6F5H using trans- [Ru(IMe4)2(PPh3)2H2] (ttt-9) ............................................................................ 86 3.4. Isolation of trans-[Ru(IMe4)2(PPh3)2HF] (ttt-14) ............................................... 88 3.5. Reactivity of [Ru(NHC)2(PPh3)2HF] with silanes .............................................. 89 3.5.1. Characterisation of [Ru(IMe4)2(PPh3)(SiR3)H3] complexes ..................... 91 3.5.2. Characterisation of [Ru(IEt2Me2)2(PPh3)(SiEt3)H3] (19) and [Ru(IEt2Me2)2(PPh3)(SiPh3)H3] (20) ....................................................................... 95 3.6. Reactivity of [Ru(IEt2Me2)2(PPh3)(C6F5)H] (11) and [Ru(IEt2Me2)(PPh3)2(C6F5)H] (12) with Et3SiH ............................................... 98 3.7. Synthesis and stoichiometric reactivity of [Ru(NHC)2(P-P)HF] complexes ...... 98 3.8. Characterisation of [Ru(NHC)2(P-P)HX] complexes ....................................... 101 3.9. Catalytic HDF of C6F6 using [Ru(NHC)2L2H2] complexes .............................. 106 3.10. Summary ........................................................................................................... 112 3.11. References for Chapter 3 ................................................................................... 113 Contents Chapter 4: C-O Bond Activation of DPEphos via Attack of Nucleophilic Ru-H in RuL4H2 4.1. Introduction ....................................................................................................... 116 4.2. Reactivity of [Ru(IMe4)2(PPh3)2H2] (ttt-9) ....................................................... 117 4.2.1. Reaction of [Ru(IMe4)2(PPh3)2H2] (ttt-9) with DPEphos ....................... 117 4.2.2. Reaction of [Ru(IMe4)2(PPh3)2H2] (ttt-9) with diphenyl(2- methoxyphenylphosphine) ..................................................................................... 122 4.2.3. Reaction of [Ru(IMe4)2(PPh3)2H2] (ttt-9) with DCEphos ...................... 123 4.2.4. Reaction of [Ru(IMe4)2(PPh3)2H2] (ttt-9) with xantphos ....................... 124 4.3. Reaction of [Ru(IEt2Me2)2(PPh3)2H2] (cct-8) with DPEphos ........................... 126 4.4. Reaction of [Ru(PPh3)4H2] (32) with DPEphos ................................................ 132 4.5. DFT studies of C-O activation by [Ru(IMe4)2(PPh3)2H2] (ttt-9) ...................... 137 4.6. Discussion ......................................................................................................... 140 4.7. Summary ........................................................................................................... 148 4.8. References for Chapter 4 ................................................................................... 149 Chapter 5: Reactivity of ruthenium dihydride complexes with P(C6F5)3 5.1. Introduction ....................................................................................................... 154 5.2. Reaction of [Ru(IMe4)2(PPh3)2H2] (ttt-9) with PCF ......................................... 154 5.3. Reaction of [Ru(PPh3)4H2] (32) with PCF and characterisation of [Ru(PPh3)3HF] (37) .................................................................................................................. 158 5.4. Reactivity of [Ru(PPh3)3HF] (37) ..................................................................... 165 5.4.1. Reactivity of [Ru(PPh3)3HF] (37) with silanes ....................................... 166 5.4.1.1. Reaction of [Ru(PPh3)3HF] (37) with R3SiH (R= Et, Ph) and characterisation of [Ru(PPh3)3(SiR3)H3] (38, R= Et; 39, R= Ph). ..................... 166 5.4.1.2. Reactivity of [Ru(PPh3)3HF] (37) with CF3SiMe3 .......................... 169 5.4.2. Reactivity of [Ru(PPh3)3HF] (37) with boranes ..................................... 170 5.4.2.1. Reactivity
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