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This Thesis Has Been Submitted in Fulfilment of the Requirements for a Postgraduate Degree (E.G This thesis has been submitted in fulfilment of the requirements for a postgraduate degree (e.g. PhD, MPhil, DClinPsychol) at the University of Edinburgh. Please note the following terms and conditions of use: • This work is protected by copyright and other intellectual property rights, which are retained by the thesis author, unless otherwise stated. • A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. • This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author. • The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. • When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Synthesis of f-block Complexes in a Polypyrrolic Macrocyclic Environment Natalie Alison Potter (neé Jones) MSci, AMRSC This thesis is submitted for the degree of Doctor of Philosophy of the University of Edinburgh 5th April 2011 i Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less. Marie Curie ii Declaration Except where specific reference has been made to other sources, the work presented in this thesis is the original work of the author. It has not been submitted, in whole or in part, for any other degree. Natalie A. Potter 5th April 2010 iii Abstract In this thesis, the chemistry of lanthanide and actinide complexes of Schiff-base, polypyrrolic macrocyclic ligands has been evaluated. Chapter one introduces some general chemistry of uranium before focussing on uranium(III) and (IV) coordination complexes of nitrogen donor ligands. The surface chemistry of uranium metal is also briefly discussed along with the synthesis of uranium borohydride, hydride and alkyl complexes. Chapter two describes the synthesis and characterisation of the monometallic complexes [M(L)] or [M(HL)], where M = Y, Ce, and U, of the octadentate Schiff- base pyrrole macrocycle H4L. In particular, these complexes display a new binding mode of the macrocycle which leads to the formation of the unique trinuclear supramolecular complexes [M(HL)]3, (M = Ce, Y). Reactions of these materials towards hydrolysis, oxygen sources and other metal reagents are also exemplified. Chapter three details the synthesis and characterisation of the bimetallic complexes, [(MX)2(L)], where M = Ce, U, and Np and X = I or Cl, and [(MX2)2(L)], where M = U, and the attempts to transform these complexes into metal hydrides via their borohydrides. The solid state variable temperature magnetism of the binuclear U(III) and Np(III) complexes was recorded and was found to be consistent with the formation of iodide-bridged, polymeric structures. Chapter four explores the synthesis and reactions of adducts between UI3 and neutral macrocyclic ligands that incorporate either oxygen or nitrogen donors such as crown ethers and cyclam, respectively. The new synthesis of the key starting material, unsolvated UI3 is also outlined, along with the full characterisation of UI4(OEt)2. iv v Acknowledgements I would like to thank my supervisors Jason and Polly for their continued support, advice and their endless enthusiasm for chemistry and to Paul my industrial supervisor for funding. Also I would like to thank the sponsors of this project; The University of Nottingham, The University of Edinburgh and the Atomic Weapons Establishment (AWE). I would like to thank the support staff at the University of Edinburgh; Mr Juraj Bella and Dr. Marika McCremoux for NMR support, Prof. Simon Parsons, Dr. Anna Collins and Dr. Fraser White for help with X-ray crystallography. Thanks go to all in lab 34 past and present, the post-docs; Steve, Chris. Manuel, Sergey, Lorena, Emmalina, Bernabe and Stephen and my fellow students; Ian, Dipti, J.-C., Mo, Stephen, James, Aline, Zoë, Anne-Fred, John, Anne, Guy, Aáron, Chloe, Isobel, Rebecca and Colin. Also I would like to thank everyone in the department, for helping us to settle in so well, especially to Jill and Phil. I would also like to thank my family for their love, and support and my sister, Michelle, for being a great chemistry role model. I would also like to thank Craig’s family who have been very supportive during my PhD. Special thanks to my husband, Craig, for his endless encouragement, and support. vi Abbreviations Å Angstrom Ad Adamantyl atm Atmosphere bar Bar, unit of pressure n-Bu n-butyl t-Bu tert-butyl Bn Benzyl ca. circa, about COT Cyclooctatetraene Cp Cyclopentadiene Cp* Pentamethylcyclopentadiene Cp‡ Monoethyltetramethylcyclopentadiene Cyclam 1,4,8,11-tetraazacyclotetradecane DABCO 1,4-diazabicyclo[2.2.2]octane DMF Dimethylformamide dme Dimethylether dmpe Bis(1,2-dimethylphosphino)ethane fc ferrocene i-Pr Isopropyl Me Methyl N′′ Hexamethyldisilyl amide 3- NN′3 [N(CH2CH2NSiMe2t-Bu)3] t t NON [N( Bu)Si(Me2)OSi(Me2)N( Bu)] Ph Phenyl Py Pyridine RT Room temperature R Generic alkyl group T tesla THF Tetrahydrofuran TMS Trimethylsilyl tpy 2,2′:6′,2′′-terpyridine Tren Tris(2-aminoethyl)amine vii Nuclear Magnetic Resonance spectroscopic data (NMR) δ chemical shift in ppm J coupling constant m multiplet ppm parts per million 13C{1H} proton decoupled 13C NMR q quaternary carbon s singlet t triplet Mass spectroscopic data EI Electron Impact m/z mass to charge ratio M+ molecular ion Infrared spectroscopic data (IR) br broad cm-1 wavenumber m medium s strong w weak SQUID data SQUID Superconducting QUantum Interference Device χ Magnetic susceptibility μ Effective magnetic moment viii For Mum, Dad, Michelle and Craig In Memory of John Clark Potter (1946 – 2010) ix Table of Contents Chapter 1: Introduction ............................................................................. 1 1.1 Uranium………………………………………………………………………1 1.2 Surface Chemistry…………………………………………………………….5 1.3 Uranium(III) and Uranium(IV) Chemistry…………..……………………….6 1.4 Uranium Hydrides…………………………….………………………………6 1.4.1 UH3…………………………………………………………………….6 1.4.2 Uranium Hydride Complexes………………………………………….8 1.5 Uranium Borohydrides…………………………………………….…….…..11 1.5.1 Uranium Alkyls .............................................................................. …..15 1.6 Uranium Amides…………………………………………………….....……17 1.7 Uranium Aryloxides……………………….…………………...……………27 1.8 Uranium Cp and COT complexes…………………………………………...28 1.9 Uranium Alkyls……………………………………..…………..…………...29 1.10 Uranium Polypyrrolic Complexes…………………………………………..32 1.10.1 Macrocyclic Uranium Complexes ....................................................... 36 1.10.2 Actinide/Lanthanide Separation............................................................44 1.10.3 Uranium Schiff Base Complexes ......................................................... 46 1.10.4 Schiff Base Pyrrole Macrocycles ......................................................... 47 1.11 References…………………………………………………………………...51 x Chapter 2: Monometallic Complexes ..................................................... 60 2.1 Synthesis of Schiff-base Macrocycles………………………………………60 Me 2.1.1 Synthesis of H4L ............................................................................... 60 Et 2.1.2 Synthesis of H4L ................................................................................ 61 2.2 Synthesis of Uranium Complexes…………………………………………...65 2.2.1 Synthesis of [U(LEt)] ............................................................................ 65 Et 2.2.2 Synthesis of [UO2(Opy)(H2L )] .......................................................... 71 2.3 Synthesis of Cerium Complexes…………………………………………….74 Et 2.3.1 Synthesis of [Ce(HL )]3 ...................................................................... 74 Et 2.3.2 Synthesis of [Ce(THF)2(HL )] ............................................................ 86 2.3.3 Synthesis of [Ce(LEt)] .......................................................................... 90 Et 2.3.4 Synthesis of [{Ce(L )}2Zn] ................................................................. 92 2.4 Synthesis of Yttrium Complexes……………………………………………95 Et 2.4.1 Synthesis of [Y(HL )]3 ........................................................................ 95 2.4.2 Synthesis of [Y(THF)2(HL)] ................................................................ 97 Et 2.4.3 Synthesis of [{Y(OH2)(H2L )}2(µ-OH)2] ......................................... 102 2.5 Conclusions…………………………………………………………..…….106 2.6 References………………………………………………………………….106 Chapter 3: Bimetallic Complexes . ……………………………………111 xi 3.1 Direct uranium–metal bonds……………………………………………….111 3.2 Multinuclear uranium complexes………………………………………….113 3.3 Synthesis of Starting Materials…………………………………………….118 Et 3.3.1 Preparation of [K4L ] ........................................................................ 118 3.3.2 Preparation of UI3(THF)4 ................................................................... 119 3.4 Synthesis of Bimetallic Complexes………………………………………..119 Me Et 3.4.1 Synthesis of [(UI)2(L )] and [(UI)2(L )] ......................................... 119 Et 3.4.2 Preparation of [(UBH4)2(L )] ............................................................ 125 Et 3.4.3 Preparation of [(UH)2(L )] ................................................................ 128 Et 3.4.4 Preparation of [(UCl2)2(L )] .............................................................. 129 Et 3.4.5 Synthesis of [(CeI)2(L )] ................................................................... 130 3.5 Neptunium Chemistry……………………………………………………...130
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