Themochemical and SPECTROSCOPIC STUDIES of SOME GOLD and TELLURIUM COMPLEXES -R V . E^Vc by Michael John Baker. a Thesis Present
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THEmOCHEMICAL AND SPECTROSCOPIC -r STUDIES OF SOME V . e^vc GOLD AND TELLURIUM COMPLEXES by Michael John Baker. A thesis presented for the degree of Doctor of Philosophy in the University of London Chemistry Department, Royal Holloway College 1982 RHC bGMSaa Ô a302 14 006045828b ProQuest Number: 10097505 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 complete 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 10097505 Published by ProQuest LLC(2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 I wish to express my sincere thanks to Dr. Arthur Finch and Dr. Peter Gates for their great help and patient counselling throughout my three years of research at Holloway. Also, my thanks to the past and present Heads of Department at Scunthorpe College of Science and Technology, Mr, Hopkinson and Mr. Watts, and to North Humberside County Council for enabling this research to be undertaken. Finally, my deepest thanks and affection to my mother, whose typing of this work and constant encouragement have been invaluable (as has the encouragement of her colleague-typistÎ). M.J. Baker. CONTENTS. 1. ABSTRACT 16 THERMOCHEMISTRY OF SOLD TETRAHALIDES. 2. INTRODUCTION 19 2a." General chemistry 19 2b. Halides of gold 26 2c. Thermodynamic properties of gold/halogen compounds 3k 2d. Background to gold thermodynamic data contained 36 in N.B.S. Circular 500 3 . EXPERIMENTAL SECTION 3a. Synthesis and analysis of the compounds used 40 3b. Aurochloric acid 40 3c. Potassium, rubidium and caesium tetrachloroaurate 40 3d. Potassium, rubidium and caesium tetrabromoaurate 41 3e. Tétraméthylammonium and tetraethylammonium 43 dibromoaurate 3f. Tétraméthylammonium and tetraethylammonium 44 dichloroaurate 3g. Tétraméthylammonium, triethylammonium and 46 tetraethylammonium diiodoaurate 3h. Reclamation of gold 50 3j. Details of reactions studied 50 3k. Calorimetry 67 3 1 . Brief description of procedure 6? 3m. Calculation of the heat of reaction ?4 3n. Titration calorimetry 76 4. RESULTS SECTION 4a. Tetrahaloaurate results (heat of solution) 85 4b. KAuCl^ 85 4c. RbAuCl^^ 88 4d. KAuBr^^ 90 4e. RbAuBrj^ 93 DISCUSSION OF RESULTS. 4f. Tetrahaloaurate results (heat of solution) 103 4g, Raman spectra IO3 4h. Calorimetric results 108 4 j. Calculations II3 4k. Summary of tetrahaloaurate results 121 Tetraalkylammonium dibromoaurate results. 122 41. Raman spectra 122 4m. Heat of reaction of Mej^NAuBr2 with FeSO^^ solution 129 4n. Heat of reaction of Et^NAuBrg with FeSOj^ solution I30 4o. Calculations I33 4p. Summary of dihaloaurate results I37 Tetraalkylammonium dihaloaurates. I38 4q. The Raman spectra of the dichloroaurates 138 4r. The Raman spectra of the diiodoaurates 144 4s. Calorimetric results of Etj^^NAuI^ with SOg (aq) 147 4t. Calculations I50 4u. Calorimetric titration results. 152 4v. KAuClj^ with aqueous ferrous sulphate I52 4w. KAuBrj[^ with aqueous ferrous sulphate 154 4x. Mechanism of the ferrous reduction of gold (III) 159 4y. Mechanism of the hydrolysis of gold (III) I63 4z. Kinetics and mechanism of the sulphite reduction 165 gold (III) 5. Antimony pentachloride and Arsenic trichloride i j q complexes of Auric Chloride. 5a. Experimental. I70 5b. Results and discussion. 6. APPENDIX III. 6a. Calculation of lattice energies by the ^ 1 7 7 Kapustinskii method 6b. Errors in lattice energy calculations via the 180 Kapustinskii equn. 7 . APPENDIX IV. Estimation of experimental errors. 182 8. APPENDIX V. Calorimetric reaction stoichiometries. 185 8a. FeSOj^ with Et^^NAuBr^ 185 8b. SO2 with Etj^NAuI^ 186 8c. FeSO^ with KAuClj^ I87 9. APPENDIX VI. Calculation of the ionic radii of the complex 188 anions 10.APPENDIX VII. THAM calibrations. I92 11.APPENDIX VIII. Activity coefficients of the calorimetric solvents 1 9 5 used SPECTROSCOPY OF TELLURIUM HALIDES AND COMPLEXES. 12. INTRODUCTION. 12a. General Chemistry. I99 12b. Halides of the Gp VI elements. 202 12c. Tellurium (II) and (IV) chlorides and bromides. 206 12d. Lewis acid complexes of tellurium tetrahalides. 214 1 3 . EXPERIMENTAL SECTION. 13a. 'Tellurium tetrachloride. 217 13b. Tellurium tetrabroraide. 219 13c. Tellurium dichloride dibromide. 220 13d. Tellurium dichloride dibromide/aluminium 222 chloride complex Tellurium Tetrabromide Complexes. 223 13e. Tellurium tetrabromide/aluminium tribromide 223 complex 13f. Tellurium tetrabromide/aluminium trichloride 226 complex 13g. Tellurium tetrabromide/antimony pentabromide 227 complex 13h. Tellurium tetrabromide/antimony pentachloride 227 complex Tellurium Tetrachloride Complexes. 228 1 3 i. Tellurium tetrachloride/aluminium tribromide 229 complex 13k. Tellurium tetrachloride/aluminium trichloride 229 complex 1 3 1. Tellurium tetrachloride/antimony penta(^lo^ide 230 14. RESULTS AND DISCUSSION SECTION. l4a. Tellurium tetrabromide and tetrachloride. 231 l4b. Tellurium dichloride dibromide. 241 I4c. Tellurium dichloride dibromide/aluminium 245 trichloride complex. 14 . Tellurium tetrabromide complexes. 247 l4d. Tellurium tetrabromide/aluminium tribromide 257 complex l4e. Tellurium tetrabromide/aluminium trichloride 273 complex l4f. Tellurium tetrabromide/antimony pentabromide 273 complex l4g. Tellurium tetrabromide/antimony pentachloride 278 complex 14_ . Tellurium Tetrachloride Complexes. 281 l4h. Tellurium tetrachloride/aluminium tribromide 281 complex 14j. Tellurium tetrachloride/aluminium trichloride 289 complex l4k. Tellurium tetrachloride/antimony pentachloride 292 complex 1 5 . APPENDIX I Characterisation and analysis of tellurium 297 compounds 16. APPENDIX II Solvent purification and drying.and tellupium 299 toxjLcity 1 7. REFERENCES. 300 18. ADDENDUM. 313 8 List of Tables. Page . 2al). Ionisation energies of group IB elements. 20 2a2). Some standard redox potentials of Au corapds. 22 2bl). Halides of gold and thermodynamic data at 27 298 K for crystalline compounds. 2cl). Examples of chemical thermodynamic properties 35 of gold halides, 3nl).. Syringe calibration for titration 80 calorimetry. 3n2). Enthalpy of neutralisation of HCl(l.OM) 81 with Na0H(0.03M). 4bl). Enthalpy of solution of KAuCl^ in water. 85 4b2). Enthalpy of solution of KAuCl^^ in HCl soins. 86 4b3). Enthalpy of solution of KAuCl^ in KNO^ soins. 87 4cl). Enthalpy of solution of RbAuCl^ in water. 88 4c2). Enthalpy of solution of RbAuCl^ in HCl soins. 89 4dl). Enthalpy of solution of KAuBr^ in water. 90 4d2). Enthalpy of solution of KAuBr^^ in HBr soins. 91 4d3). Enthalpy of solution of KAuBr^ in NaC10|^ 92 soins. 4el). Enthalpy of solution.of RbAuBr^ in water. 93 4e2). Enthalpy of solution of RbAuBr^ in HBr soins. 94 4gl). Vibrational spectra of AuCl^. 4g2). Vibratipnal spectra of AuBr^. e 4jl). Estimation of AH^y^^ and AH^^^ values for 120 AuCl^ and AuBr^ (R.M. de Jonge). 4j2). AH^y^^ and AH^^^ values for AuCI^ and AuBr^ 120 (this work). 4k). Summary of the tetrahaloaurate results. 121 411). Vibrational spectra of the tetraalkylammonium 123 dibromoaurate. 4m). Enthalpy of reaction of Me^NAuBrg with FeSO^. 12? 4n). Enthalpy of reaction of Et^NAuBr2 with FeSO^. I30 4p). Summary of the dihaloaurate results. 137 4ql). Raman spectrum of Etji^NAuCl2 (s ). 141 4s). Enthalpy of reaction of Et^NAuIg in SO^ soins. 147 4v). Calorimetric KAuCl^ results(titration). 152 4wl). Calorimetric KAuBr^ results(titration). 15^ 5bl). Raman spectrum of auric chloride (Adams and 173 Churchill). 8al). Stoichiometry of the FeS0 ^/Et^NAuBr2 reaction. 185 8bl). Stoichiometry of the S02 /Et^NAul2 reaction. 186 8cl). Stoichiometry of the FeSO^^KAuCl^^ reaction. 187 loal). Endothermie tham calibrations. 192 lobl). Exothermic tham calibrations. 193 12 al). Ionisation energies of the group VI elements. 201 12 bl). Halides of the group VI elements (& structures 203 of the halides). I4al). Raman spectra of the solid tellurium tetra 232 halides . I4bl). Raman spectrum of solid TeCl2 ,Br2 . 246 l4cl). Raman spectra of the TeCl2 Br2 /AlCl^ salts. 252 I4dl). Raman spectra of the TeBr^/AlBr^ products. 260 I4el). Raman spectrum of the TeBr^/AlCl^ product. 270 I4fl), Raman spectrum of the TeBr^SbBr^ product. 276 I4gl). Raman spectrum of the TeBr^SbCl^ product. 279 I4hl). Raman spectrum of the TeCl^/AlBr^ product. 285 10 14jl). Raman spectrum of the TeCl^/AlCl^ product. 2 9 I l4kl). Raman spectrum of the TeCl^SbCl^ product. 295 11 List of Figures. Page 2 bl). Au^Clg 29 2b2). Electronic absorption spectra of KAuCl^ in KCl,32 KAüBr^ in KBr and KAuCl/^KAuBr^ in KI. 2b3). Electronic absorption spectra of AuGl” , AuBr^ 33 and AUI2 in acetonitrile. 3 jl). Raman spectra of RbAuBr^ in aq. NaOH soins. 60 3j2). Raman spectrum of CsAuCl^AgNO^ precipitate. 6l 3j3). U.V./vis. spectra of AuBrJJ/AgNO^ reactants 62 and products. 3j4). Chart of transmittance at 381 nm on addition of&3 AgNO^(excess) to CsAuBr^(aq) + HNO^(aq). 3j5). Potentiometric trace of the AgNO^/CsAuCl^(aq) 64 reaction. 3 1 1). The calorimeter. 68 3 1 2 ). The experimental apparatus. 69 3ml). Exothermic reaction trace (eg tham with HCl) 77 and calibration trace. 3m2). Endothermie reaction trace (eg Me^NAuBr^ reactn?^ with FeSO^) and calibration trace. 3nl). Example exothermic titration trace and ^ calibration. 4el). Graph