UNIVERSITY OF CALGARY Expanding the Scope of Boraamidinates: Ligand Modification and f-Block Complexes by Andrea Marie Corrente A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY CALGARY, ALBERTA AUGUST, 2010 © Andrea Marie Corrente 2010 Library and Archives Bibliothèque et Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l’édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre référence ISBN: 978-0-494-69539-5 Our file Notre référence ISBN: 978-0-494-69539-5 NOTICE: AVIS: The author has granted a non- L’auteur a accordé une licence non exclusive exclusive license allowing Library and permettant à la Bibliothèque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l’Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans le loan, distribute and sell theses monde, à des fins commerciales ou autres, sur worldwide, for commercial or non- support microforme, papier, électronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L’auteur conserve la propriété du droit d’auteur ownership and moral rights in this et des droits moraux qui protège cette thèse. Ni thesis. Neither the thesis nor la thèse ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent être imprimés ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author’s permission. In compliance with the Canadian Conformément à la loi canadienne sur la Privacy Act some supporting forms protection de la vie privée, quelques may have been removed from this formulaires secondaires ont été enlevés de thesis. cette thèse. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n’y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. ii Abstract A critical aspect of coordination chemistry is ligand design. Boraamidinates 2- - ([RB(NRʹ)2] , bams) are isoelectronic to amidinates ([RC(NRʹ)2] , ams) and guanidinates - ([R2NC(NRʹ)2] , guans), however, the boron-containing ligands are comparatively less well studied. For instance, all known bams are dianionic with either alkyl or aryl substituents on boron and only complexes of the main group and d-block elements are found in the literature. This thesis focuses on further developing the chemistry of bams through ligand modification and preparation of f-block complexes. 2- The first example of a stable dilithio boraguanidinate ([R2NB(NRʹ)2] , bog) is presented; metathesis reactions reveal that this electron-rich ligand is a strong reducing agent. A novel seven-membered C4OBN heterocycle, isolated while exploring alternative synthetic routes to the bog ligand, represents the first example of a structurally characterized 1,3,2-oxazaborepane. Altering bams by either incorporating a spacer group on boron or by mono- metallation is achieved. New ferrocenyl (diamino)boranes are prepared and deprotonation is attempted in the pursuit of ferrocenyl bis-boraamidinates. The first example of a t t tetralithio bis-bam ligand, [Li4][( BuN)2B−C6H4−(N Bu)2], is found to be extremely air- sensitive. Single deprotonation of PhB[N(H)Dipp]2 with either butyllithium or benzyl potassium gives the monoanionic bams [M][PhB{N(H)Dipp}(NDipp)] (M = Li, K). The new dianionic bam reagent [K2][PhB(NDipp)2], which is obtained from double deprotonation of PhB[N(H)Dipp]2 with benzyl potassium, is useful for preventing the inclusion of a salt by-product in metathetical reactions. iii The coordination chemistry of the bam ligand is extended to the f-block elements in the preparation of “ate” complexes of the form {[Li(THF)4][{PhB(NDipp)2} LnCl2(THF)]}2 (Ln = Y, Pr, Nd, Sm, Ho, Er, Yb) and 2:1 spirocyclic species [Li2(THF)8][{PhB(NDipp)2}2LnI] (Ln = La, Sm). The reaction of the yttrium and samarium “ate” complexes with an excess of trimethylsilyl trifluoromethanesulfonate generates {[PhB(NDipp)2]LnCl(THF)2}2. The analogous iodide species are prepared from the reaction of [K2][PhB(NDipp)2] and LnI3(THF)3.5 and metathesis reactions of both neutral complexes are examined. Extensive attempts to form a samarium(II) bam complex reveal that protonolysis is the preferred route over metathesis or reduction. iv Acknowledgements I would first like to thank Dr. Tristram Chivers for being an incredible supervisor. His enthusiasm and involvement in all of my projects is greatly appreciated and the wealth of knowledge I gained from our numerous discussions is immeasurable. I would also like to acknowledge the members of the Chivers group with whom I had the privilege to work over the past four years: Drs. Jari Konu, Stuart Robertson, Jamie Ritch, Dana Eisler, Maarit Risto and Tracey Roemmele. It was a pleasure being a part of this group of excellent chemists, colleagues and friends. I would like to extend my appreciation to Dr. Warren Piers and Dr. Thomas Baumgartner for being members of my supervisory committee, to Dr. George Shimizu who participated in my qualifying exam, and to Dr. Nasser Moazzen-Ahmadi who acted as my internal-external for both examinations. Many thanks to Dr. Alan Cowley for agreeing to make the trip up north to Calgary to serve as my external examiner. Dr. Sjoerd Harder provided very helpful correspondence when I ventured into the world of lanthanide boraamidinates and I want to express my gratitude to him, especially for his inspirational words that got me through some very frustrating times in the lab: “This bam chemistry is not easy!”. Thanks as well to Dr. Chuck Macdonald for giving me the push I needed to leave Windsor for grad school - it really was the right decision! As all chemistry graduate students at UofC know, we would not get through our degrees without the extraordinary efforts of Bonnie King. From lending a sympathetic ear to making sure our i's are dotted and t’s are crossed before a deadline hits, Bonnie keeps everyone on track and her genuine care for the students is something you don’t find just anywhere. v I’d also like to say thank you to the members of the instrumentation team, including Dr. Masood Parvez, Dr. Yamdagni, Dorothy Fox, Qiao Wu and, in particular, Johnson Li and Wade White who always gave it their best shot with my less-than- cooperative samples. I truly appreciate your time and efforts! Mike Siewert, Ed Cairns and Keith Collins were essential in keeping our glove box and ovens running, which warrants a huge thank you! Additionally, I would like to acknowledge NSERC, Alberta Ingenuity and the University of Calgary for providing ample funding throughout my PhD studies. Although I came to Calgary knowing not a single person, I am fortunate to now have so many friends here that acknowledging each of them would require me to add Appendix C to this document; I appreciate everyone who has been a part of my Calgary life and would like to take a moment to mention a few specific people. Thanks to Josh Smith for wearing a Toronto Maple Leafs shirt during orientation making for easy conversation, for putting up with my homesick *moments* during our first year here and for inviting Korwin to be his Calgary roommate when he came to town. Thank you to Matt Hobbs for opening my eyes to the greatness of the CFL, pushing me well beyond my limits in the mountains and for our numerous chemistry “discussions”. A very special thanks to Dr. Sean Dalrymple and Alana Keen for being great friends and for all the fun times we’ve shared in Calgary and The ‘Stoon. It has also been nice having fellow Macdonald group alumnus Paolo Bomben in the department to keep up with what’s going on at home - I wish him luck with the rest of his degree. I am fortunate to have wonderful family and friends from Windsor who have supported me throughout my University career. I am forever indebted to my incredible vi parents, whose love and support has gotten me through the roughest of times; even though they probably don’t realize it, I really couldn’t have made it this far without them. Thank you to my sister and brother, Kimberly and Christopher, for the text messages and iChats that on some days made me homesick and on others made me happy to be 3000 km away! I would also like to thank my Nonna for all of her prayers and for getting excited about every little success I had in grad school. To my great friends Lindsay, Dana, Melissa and Kendall – thanks for all of the random chats and messages and your visits to CowTown. I would also like to express thanks to Dr. Sharonna Greenberg not only for regular phone dates but also for taking the time to read this thesis and provide me with awesome feedback. And finally, to my best friend, life co-pilot and soon-to-be-husband Korwin: your daily support and encouragement and your endless tolerance of chemistry talk is appreciated more than I can ever explain. If we made it through grad school together, we can make it through anything!! vii Dedication For their endless love and support and for always believing in me, I dedicate this thesis to my parents, Mary Jean and Silvio. viii Table of Contents Approval Page.................................................................................................................ii