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Conorflemingphdthesis.Pdf (3.852Mb) Geminally Bis(supermesityl) Substituted Phosphorus Compounds and A Study of 5,6-Substituted- Acenaphthenes By Conor Gareth Edward Fleming A thesis submitted in partial fulfilment for the award of Doctor of Philosophy The School of Chemistry University of St Andrews North Haugh St Andrews Fife KY16 9ST 31st January 2013 i Declaration I, Conor Gareth Edward Fleming, hereby certify that this thesis, which is approximately 39,000 words in length, has been written by me, that it is the record of work carried out by me and that it has not been submitted in any previous application for a higher degree. I was admitted as a research student in September 2008 and as a candidate for the degree of Doctor of Philosophy in August 2009; the higher study for which this is a record was carried out in the University of St Andrews between 2008 and 2013. Date Signature of candidate I hereby certify that the candidate has fulfilled the conditions of the Resolution and Regulations appropriate for the degree of Doctor of Philosophy in the University of St Andrews and that the candidate is qualified to submit this thesis in application for that degree. Date Signature of supervisor ii In submitting this thesis to the University of St Andrews I understand that I am giving permission for it to be made available for use in accordance with the regulations of iii Abstract This thesis describes the effect of placing a phosphorus atom in a sterically strained environment with particular emphasis on the geminal disubstitution of two 2,4,6-tri- tert-butylphenyl iv Acknowledgements First and foremost, I would like to thank my supervisor Dr. Petr Kilian who has provided expert guidance and support throughout my time at St Andrews. I also thank him for his assistance in producing this thesis. Any errors and/or omissions contained within are attributable solely to me. Furthermore, I would like to thank Profs. Alex Slawin and Derek Woollins for their help and support through the years. I am indebted to our former group member Dr. Piotr Wawrzyniak for his practical help, especially at the start of my research and to Dr. Fergus Knight for his help towards the end of it. I would also like to thank Caroline Horsburgh (MS), Stephen Boyer (EA) and Melanja Smith & Dr. Tomas Lebl (NMR spectroscopy) for their technical expertise. All of the members (past and present) of the Kilian/Slawin/Woollins conglomeration of research groups, from supervisors down to undergrad project students, have contributed to producing a friendly working environment in the lab with good humour and banter. I therefore thank (in no particular order) Brian MF, Brian S, Jacks, Hua, Upu, Vit, Amy, Tim, Paul, Matt, Ken, Becca, Lucy, Joy, Kasun, Brian C, Andreas, Louise, Steffi, Anna, Paula, Nick and Nikolay. I hope any future workplace which I find myself in will be filled with as much fun and dinosaurs as I found here. The Science-Fiction and Fantasy, Doctor Who and Mostly Harmless societies have played a massive part in my life in St Andrews and I met a huge amount of amazing people through them. I particularly want to thank Lucy, Ally and Sian for being awesome. I am grateful to EPSRC and EaSTCHEM for funding my research. Finally, I would like to thank my family and in particular my parents without whom I could not have got where I am now. Their love and support through thick and thin has allowed me to achieve my educational goals. v Table of Contents Declaration ..................................................................................................................... ii Abstract ......................................................................................................................... iv Acknowledgements ........................................................................................................ v Table of Contents .......................................................................................................... vi List of Figures ............................................................................................................... ix List of Schemes ............................................................................................................. xi List of Tables ............................................................................................................... xii Abbreviations ............................................................................................................. xiii Preamble ..................................................................................................................... xvi Chapter 1 – Introduction to Phosphorus Chemistry and Bulky Substituents................. 1 1. Phosphorus and its chemistry............................................................................. 1 a. Phosphorus: occurrence and uses............................................................... 1 b. Phosphorus nomenclature .......................................................................... 2 c. Phosphorus chemistry & reactions............................................................. 5 d. Phosphorus-oxygen double bonds ............................................................. 6 e. 31P NMR spectroscopy and variable temperature measurements .............. 7 2. The use of sterically hindering substituents ....................................................... 9 a. Reactive species and steric protection ....................................................... 9 b. Sterically protected phosphorus compounds in the literature .................. 11 c. Supermesityl and 2,4,6-triisopropylphenyl .............................................. 14 3. Main group Radicals ........................................................................................ 18 a. Introduction to main group radicals ......................................................... 18 b. Radical nomenclature and generation ...................................................... 18 c. Phosphorus radicals nomenclature ........................................................... 19 d. Phosphorus radical examples ................................................................... 19 e. Spin labelling and EPR ............................................................................ 22 Chapter 2 - Geminally Bis(supermesityl) Substituted Phosphorus Compounds ......... 23 1. Supermesityl and steric hindrance ................................................................... 23 a. Mes* in Main Group Chemistry .............................................................. 23 b. The production and previous studies of Mes*2P(=O)Cl in the literature 24 c. Other bis(supermesityl) substituted phosphorus compounds in the literature ................................................................................................... 25 d. Possible routes to phosphinyl radicals ..................................................... 27 e. Structural and Spectroscopic characteristics of Mes*2P(=O)Cl .............. 28 2. Reactivity of Mes*2P(=O)Cl ............................................................................ 31 a. Reaction with organolithium.................................................................... 31 b. Reduction of Mes*2P(=O)Cl .................................................................... 31 c. Synthesis of Mes*(2,4-tBu2C6H3)PH....................................................... 33 d. Reduction conditions ............................................................................... 34 3. The Structural and spectroscopic characteristics of Mes*2P(=O)H and its further reactions ............................................................................................... 36 a. Spectroscopic study of Mes*2P(=O)H ..................................................... 36 b. Deprotonation of Mes*2P(=O)H 5 ........................................................... 37 c. Reaction of phosphinite 7 with alkyl halides ........................................... 38 d. Reaction of phosphinite 7 with halogens ................................................. 39 e. Reduction of Mes*2P(=O)Me 8 ............................................................... 39 f. X-ray discussion of 4, 5, 8 and 9 ............................................................. 41 g. Computational discussion ........................................................................ 49 vi 4. The structure of Mes*(2,4-tBu2C6H3)PH and its further reactions .................. 54 a. Production and potential deprotonation of Mes*(2,4-tBu2C6H3)PH ....... 54 b. Chlorination of Mes*(2,4-tBu2C6H3)PH .................................................. 55 c. Boronation, thionation and selenation of Mes*(2,4-tBu2C6H3)PH ......... 56 d. X-ray discussion of the novel compounds 10, 13 and 14 ........................ 58 5. Experimental .................................................................................................... 64 General notes ................................................................................................... 64 6. Conclusions and unanswered questions ........................................................... 81 Chapter 3 - A Study of Phosphorus Substituted Naphthalenes and Acenaphthenes ... 83 1. Introduction to PAHs ....................................................................................... 83 a. The structure of naphthalene and acenaphthene ...................................... 83 b. Peri-substitution on naphthalene ............................................................. 84 c. Peri-substitution on
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