REDOX AND ADDITION REACTIONS OF BINARY FLUORIDES A thesis submitted to the University of Glasgow in fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY by JOHN ALBERT BERRY B.Sc, Department of Chemistry, University of Glasgow, GLASGOW, December. 1976. ProQuest Number: 13804100 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 13804100 Published by ProQuest LLC(2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 "There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact" Mark Twain "It is better to meet a mother bear robbed of her cubs than to meet some fool busy with a stupid project". Proverbs, 1£, 12 (Good News Bible) Acknowledgements I wish to express my sincere gratitude to my supervisors, Professor D.W.A, Sharp and Dr, J,M, Winfield for their help, encouragement and patience throughout this work, I should like to acknowledge the help and encourage­ ment I received from Dr, A, Prescott, especially with the work involving UF^ in CH^CN, I should also like to thank all my research student colleagues and the many members of staff who helped me, in particular Drs. R,T, Poole, I,D, MacLeod, Messrs. T, Boyle and 0,R, Chambers for helpful discussions, and Drs, R, ICeat, A,P, Lane and A,L, Porte for n,m.r,^laser Raman^and e.p.r, facilities respectively. The award of an S.R.C, Research Studentship is gratefully acknowledged. Abstract This thesis describes the study of complexation and redox reactions of iodine pentafluoride, and redox and addition reactions of uranium hexafluoride and rhenium hexafluoride# Solutions of IF,. in acetonitrile and pyridine were 1 19 studied using Raman, H and F n.m.r, spectroscopy. In CH^CN solution, the I-F»««I contacts which occur in liquid IF^, are replaced by C=N*»»I contacts as the concentration of CH^CN increases, A large decrease in the frequency of the v. band of IF-, and small increases in the C-C and C=N 1 5 stretching frequencies of CH^CN are observed in the Raman spectra. The results obtained suggest a maximum number of four CH-CN molecules can co-ordinate to each IF- A 1:1 3 5' complex is formed between IF,- and C^H^N and spectra of mixtures of the two liquids can best be explained in terms of an equilibrium between this complex and the two components. The solid 1:1 adduct, IF,-, 1 ,4-Dioxane was prepared and characterised by elemental analysis and 1 19 vibrational spectroscopy. Vibrational, and H and F n.m.r, spectra were recorded of its solutions in CH^CN, A polymeric structure for the adduct, based on a chain-structure is suggested. Reactions of IF- with metals and metal fluorides were 5 investigated, using IF,- or CH^CN as solvent. Thallium metal -f* reacts with IF^ to form insoluble T1 IF^ , which readily hydrolyses to give TIIOF^, Silver metal reacts with IF^ in CH^CN to give a viscous oil, whose spectra indicate that IF^~ is not formed. The reaction between copper and 1F,- in CH^CN gives a blue-white soluble solid whose composition is variable. The product from the reaction between mercury and IF,- is also of variable composition. Thallium (I) fluoride reacts with IF,- in CH^CN to give (Tl^^IF^"" as one product. These redox reactions all involve a 2-electron reduction of I(V) to I(III), but the reaction products depend on the stability of the I(III) species towards disproportionation# The products were identified by elemental analysis and vibrational spectroscopy. The addition reactions of IF^ with metal fluorides indicate that, in at least some instances, adduct formation is preferred to fluoride ion addition, T1F reacts with IF,- to produce either the soluble solid T1F.IF,- or the viscous liquid T1F,3IF^, The latter is formed if IF,. is present in a very large excess. reac^s in CH^CN forming the adduct CuF^,4CI1^CN.4IF^, This is a blue-green oil and 1 19 was characterised by elemental analysis, H and F n.m.r,, e,p,r,, electronic and vibrational spectroscopy, A structure based on these data is presented. Tungsten hexafluoride and molybdenum hexafluoride do not react with iodine in IF- but rhenium hexafluoride forms 5 a stable solution containing the I^ ion. This was confirmed by electronic and resonance Raman spectroscopy. No isolable product is formed. Uranium hexafluoride also forms a species containing , but a further reaction occurs and uranium pentafluoride is obtained as a pale green precipitate, UF^ is very soluble in CH^CN, with which it forms an isolable 1:1 adduct, and was characterised in the solid state by vibrational spectroscopy and in solution by Raman and electronic spectroscopy. Thallium, cadmium and copper metals are all readily oxidised by UF^ in CH^CN, forming soluble hexa- fluorouranates(V), These are isolable as the solvates T1(UF6)3.5CH3CN, Cd(UF6)2.5CU3CN and Cu(UF6)2.5CH CN, Electronic spectra obtained agree with the latest literature spectra. Values of vibrational frequencies obtained from vibronic couplings in electronic spectra agree well with the values from i.r. spectra. No silver compound could be isolated because of rapid solvent polymerisation caused by UF^ in the presence of Ag# UF^ is reduced by CH^CN to give UF^, while the solvent is slowly polymerised. The increase in concentration of UFt- with time is seen from Raman and electronic spectra, run at 30 minute intervals. attacks CH^CN too rapidly to allow reactions involving excess ReF^ to be carried out. However Cu(ReF6)2,4CH3CN.O,5IF5 was prepared using a mixture of IF- and CI10CN as solvent. 5 3 The reduction of UF^ by CH^CN to give UF^, interferes with relatively slow reactions such as F ion addition, HgF2 and UF6 in CI^CN give Hg(UF6)2,6CH3CN, and no U(Vl) species is isolated, ^u-^2 an(^ ^ 6 a mi-x^ure U(V) and U(VI) compounds and the equilibrium UF„2“ + UF^ -----* UF„~ + UF.~ o o x ( o is believed to exist in the reaction mixture, CuF^. 4CHo0N 4IFC behaves as a fluoride ion donor towards 2 ‘ 3 * 5 PFC and WF, in CH^CN The PF*"" ion was detected in solution 5 6 3 ' 6 by ^F, and ^ P I.N,D,0,R, n.m.r. spectroscopy, while WF^~ 1 9 was observed in both F n.m.r, and Raman spectra. However, the reactions between CuF0 4C1LCN 4IF_ and ReF^ and UI<V 2' 3 * 5 6 6 in IF,- are much less straightforward. The products were not completely characterised, but fluorido ion addition is at most only a side reaction. This may indicate that UF^ and ReF^ are poorer F acceptors than PF,- and WF^# Another explanation is that despite the F~ ion donor properties of CuF^,4CH^CN,4IF^ in CH^CN, it does not behave as such in IFC The co-ordinated CbLCN in CuF0 4CH0CN 4IFC 0 J 2 3 * 5 remains unattacked, despite high concentrations of ReF^ or UF^ and a long period of reaction. TABLE OF CONTENTS Page INTRODUCTION 1 CHAPTER ONE EXPERIMENTAL TECHNIQUES 48 CHAPTER TWO REACTIONS OP IODINE PENTAPLUORIDE 62 WITH ORGANIC BASES I Liquid Iodine Pentafluoride 65 II Iodine Pentafluoride and Acetonitrile 68 III Iodine Pentafluoride and 1,4-Dioxane 77 IY Iodine Pentafluoride and Pyridine 83 Experimental 92 CHAPTER THREE REACTIONS OF IODINE PENTAPLUORIDE 94 WITH METALS AND METAL FLUORIDES I Reaction of Thallium with IF_ 97 5 II Reaction of Thallium(l) Fluoride 101 with IFC j III Reaction of Thallium(l) Fluoride 102 with IF,- in the presence of CH^CN IV Reaction of Thallium(III) Fluoride 106 with IF,- in the presence of CH^CN V Reaction of Mercury with IF,- 106 VI Reaction of Silver with IFC 110 5 VII Reaction of Silver with IFC in the 110 5 presence of CII^CN VIII Reaction of Gold with IFC in the 112 5 presence of CH^CN IX Reaction of Copper with IF^ l12 X Reaction of Copper with IF,- in the 112 presence of IF,- Page XI Reaction of Copper(ll) Fluoride 115 with IF_ in the presence of CH-CN 5 1 3 Experimental 133 CHAPTER POUR REACTIONS OF METAL HEXAFLUORIDES 143 WITH IODINE IN IODINE PENTAFLUORIDE I Iodine in Iodine Pentafluoride with 144 Tungsten or Molybdenum Hexafluoride, II Iodine in Iodine Pentafluoride with 144 Rhenium Hexafluoride, III Iodine in Iodine Pentafluoride with 151 Uranium Hexafluoride IV Metal Hexafluorides with Bromine in 157 Iodine Pentafluoride Experimental 148 CHAPTER FIVE REDOX REACTIONS IN ACETONITRILE, 160 REACTIONS OF URANIUM AND RHENIUM HEXAFLUORIDES WITH METALS I Oxidation of Metals by Uranium 162 Hexafluoride in Acetonitrile II Reduction of Uranium Hexaflucride 174 by Acetonitrile III Oxidation of Copper by Rhenium 179 Hexafluoride Experimental 181 CHAPTER SIX FLUORIDE ION ADDITION REACTIONS, 185 REACTION OF COPPER(II) FLUORIDE WITH URANIUM HEXAFLUORIDE, AND COPPER(II) FLUORIDE TETRAKIS— (ACETONITRILE) TETRAKIS-(IODINE PENTAFLUORIDE) WITH PHOSPHORUS PENTAFLUORIDE, TUNGSTEN HEXAFLUORIDE, RHENIUM HEXAFLUORIDE AND URANIUM HEXAFLUORIDE, Page I Reaction of Copper(II) Fluoride 186 with Uranium Hexafluoride in Acetonitrile, II Reaction of Copper(ll) Pluoride 189 tetrakis-(Acetonitrile) tetrakis- (Iodine Pentafluoride) with Phosphorus Pentafluoride and Tungsten Hexafluoride in Acetonitrile and with Rhenium Hexafluoride in Iodine Pentafluoride Experimental 197 APPENDIX 201 REFERENCES 206 LIST OF TABLES AND FIGURES TABLE PAGE FIGURE PAGE 1 3 1 22 2 4 2 23 3 9 3 25 4 21 4 27 5 37 5 51 6 66 6 55 7 69 7 57 8 79 8 58 9 84 9 58 10 85 10 63 11 8T .