Low Oxidation State Group 15 Chemistry: New Synthetic Methods Towards Polymers By Erin L. Norton A Thesis Submitted to the Faculty of Graduate Studies and Research through the Department of Chemistry and Biochemistry in Partial Fulfillment of the Requirements for the Degree of Master of Science at the University of Windsor Windsor, Ontario, Canada 2008 Library and Bibliotheque et 1*1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-42260-1 Our file Notre reference ISBN: 978-0-494-42260-1 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library permettant a la Bibliotheque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, prefer, telecommunication or on the Internet, distribuer et vendre des theses partout dans loan, distribute and sell theses le monde, a des fins commerciales ou autres, worldwide, for commercial or non­ sur support microforme, papier, electronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in et des droits moraux qui protege cette these. this thesis. Neither the thesis Ni la these ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent etre imprimes ou autrement may be printed or otherwise reproduits sans son autorisation. reproduced without the author's permission. In compliance with the Canadian Conformement a la loi canadienne Privacy Act some supporting sur la protection de la vie privee, forms may have been removed quelques formulaires secondaires from this thesis. ont ete enleves de cette these. While these forms may be included Bien que ces formulaires in the document page count, aient inclus dans la pagination, their removal does not represent il n'y aura aucun contenu manquant. any loss of content from the thesis. •*• Canada © 2008 Erin L. Norton Abstract During the past two decades significant advances have been made in the area of low valent phosphorus chemistry. Much of the more recent work has focused on developing controlled synthetic methods, as well as understanding reactivity of compounds bearing phosphorus atoms in unusually low oxidations states. One of the most studied classes of stable compounds containing P(+l) centers are the triphosphenium salts that consist of a dicoordinate phosphorus cation ligated by two phosphines or a diphosphine ligand. New and improved syntheses of such salts containing halide counter anions were developed and are presented in this thesis. Polyphosphazenes are an important class of phosphorus containing polymers. Although methods exist to replace the phosphinyl fragments within the polymer backbone, methods to replace the nitrogen atoms were unknown. Methods for the substitution of these atoms with P(I) centers were developed and are anticipated to produce new groups of polymers with unique properties. IV Co-Authorship Statement Much of the material contained within this document has been previously published in peer-reviewed journals. In accordance with regulations defined by the Faculty of Graduate Studies, this dissertation is presented in manuscript format. I was the principal investigator for all publications and I had a significant role in the preparation of the manuscripts. I acknowledge my supervisor Dr. Charles L. B. Macdonald as a co­ author in this work as he also made significant contribution to the writing of manuscripts. Other listed authors on manuscripts contributed through raw data acquisition. Also, Jonathon Dube assisted in collection of raw data for both Chapters 3 and 4. The dissertation is based on the following publications: Chapter 1 The writing of this chapter will go towards an invited Perspectives Article in the periodical Dalton Transactions of the Royal Society of Chemistry. It is expected that this work will be submitted shortly after the dissertation is defended. Chapter 2 Norton, E.L., Szekely, K.S., Dube, J.W., Bomben, P.G., Macdonald, C.L.B., Inorg. Chem., 2008, 47, 1196-1203. DOI: 10.1021/ic701342u. Chapters 3 & 4 This work has not been published. v Dedicated to B. C. Norton vi Acknowledgements First and foremost I must thank my supervisor Dr. Chuck Macdonald for the opportunity he has given me, and all of the encouragement and support he provided me during my master's. No question was too stupid for Chuck and he was always encouraging when things weren't going well. I would like to thanks all the Macdonald Group members especially Ben Cooper for his friendship and collaborative lab efforts; Bobby Ellis for showing me "the ropes" when I first started; the undergrads who have contributed to this work: Paolo Bomben, Kara Szekely, and especially Jon Dube for his hard work and enthusiasm. Also thanks to the other "Macdonald's"-Erica Morasset, Chris Andrews, Rajoshree Roychowdhury, Greg Farrar, Mike Stinchcombe and Tamara Milovic. Special thanks to Drs. Sam Johnson, Jim Green, and Holger Eichorn for their help in anything from Glove Box Maintenance to translating German journal articles. Also thanks to the Johnson group members, Jill, Meghan, and Ritu for fun in the office. I thank my family for all their support especially my mother who has been through a lot in the past several years, but has taught me to persevere. A special thanks to Aaron Rossini for encouragement and support. Lastly, there is someone who will never read this thesis, but has probably influenced it the most. My dad taught me to be respectful, to have integrity and to take pride in everything I do. I know he wouldn't have understood an ounce of the chemistry within, however he would have enthusiastically read this thesis from cover to cover. vii Statement of Originality I certify that this thesis, and the research to which it refers, are the product of my own work and that any ideas from the work of other people, published or otherwise, are fully acknowledged in accordance with the standard referencing practices of the discipline. I acknowledge the helpful guidance and support of my supervisor Dr. C.L.B. Macdonald. viii Table of Contents Abstract iv Co-Authorship Statement v Dedication vi Acknowledgements vii Statement of Originality viii List of Tables x List of Figures and Schemes xi List of Abbreviations, Symbols, Nomenclature xiv Chapter 1 - Introduction into Low Oxidation State Main Group Chemistry 1 1.1 General Introduction 1 1.2 Oxidation States, Valence States and Our Model 2 1.3 Examples of Low Oxidation State Main Group Elements 5 1.3.1 Phosphine Ligands 6 1.3.2 iV-heterocyclic Carbene Ligands 17 1.3.3 Iniine-containing Ligands and Related Ligands 22 1.4 Dissertation Overview 27 1.5 References 29 Chapter 2 - A Convenient Preparative Method for Cyclic Triphosphenium Bromide and Chloride Salts 33 2.1 Introduction 33 2.2 Experimental 36 2.3 Results and Discussion 45 2.4 Conclusions 59 2.5 References 60 Chapter 3 - Small Molecular Targets as Monomers for Polymerization 63 3.1 Introduction 63 3.2 Experimental 68 3.3 Results and Discussion 75 3.4 Conclusions 87 3.5 References 88 Chapter 4 - Development of an Improved Synthesis of N-Heterocyclic Phosphenium Salts 90 4.1 Introduction 90 4.2 Experimental 92 4.3 Results and Discussion 96 4.4 Conclusions 102 4.5 References 104 Chapter 5 - Dissertation Summary and Future Considerations 106 5.1 Dissertation Summary 106 5.2 Future Considerations 107 5.3 References Ill Vita Auctoris 112 ix List of Tables Table 2.1. P NMR shifts corresponding to the acyclic and cyclic intermediates as well as the product for the room temperature reaction of PCI3 + bis(diethylphosphino)propane (depp) 35 Table 2.2. Summary of X-ray crystallographic data for compounds 2.7[Br], 2.8[Br] and 2.8[HC12] 43 Table 2.3. Summary of X-ray crystallographic data for compounds [dppe(OH)2][Br] and [dppe(0)(OH)][Br] 44 Table 2.4. Selected Metrical Parameters for compounds 2.7[Br], 2.8[Br] and 2.8[HC12]. Distances are reported in angstroms and angles in degrees; for 2.7[Br], the corresponding values for each independent cation in the asymmetric unit are reported separately 52 Table 2.5. Selected Metrical Parameters for compounds [dppe(OH)2][Br]2 and [dppe(0)(OH)][Br3]. Distances are reported in angstroms and angles in degrees 57 Table 3.1. Summary of X-ray crystallographic data for compounds 3.7 74 Table 3.2. Selected Metrical Parameters for compound 3.7. Distances are reported in angstroms and angles in degrees; the corresponding values for each associated bond length are reported separately 80 Table 4.1. Summary of reaction attempts to form [Mes-DAB-P][Br] 94 Table 4.2. 31P{!H}-NMR experiment results for the reactions in Table 1. Most intense signal in each spectrum denoted by * 95 x List of Figures and Schemes Figure 1.1. Some examples of our model of correlating Lewis Stucture to Oxidation State based on the number of "lone pairs" of electrons associated with the central atom. Phosphorus is used as an example 4 Figure 1.2. Ambiguity in Lewis-type chemical structure drawings of a single cation having the formula [P(PR3)2] 4 Scheme 1.1. First isolation of a cyclic triphosphenium salt 7 Scheme 1.2. Isolation of an acyclic triphosphenium salt 7 Scheme 1.3. First Synthesis of an diphosphine stabilized Arsenium salt 7 Scheme 1.4.