InhaltsangabePreface xiii CompanionWebsite xv Acknowledgements xvii Biographies xix 1. Determining Structures - How and Why 1 1.1 Structural chemistry - where did it come from? 1 1.2 Asking questions about structure 4 1.3 Answering questions about structure 5 1.4 Plan of the book 7 1.5 Supplementary information 8 2. Tools and Concepts 9 2.1 Introduction 9 2.2 How structural chemistry techniques work 10 2.3 Symmetry 11 2.4 Electron density 21 2.5 Potential-energy surfaces 21 2.6 Timescales 24 2.7 Structural definitions 26 2.8 Sample preparation 27 2.9 Quantitative measurements 30 2.10 Instrumentation 32 2.11 Data analysis 36 3. Theoretical Methods 45 3.1 Introduction 45 3.2 Approximating the multi-electron Schrodinger equation 46 3.3 Exploring the potential-energy surface 52 3.4 Extending the computational model to the solid state 56 3.5 Calculating thermodynamic properties 61 3.6 Calculating properties of chemical bonding 63 3.7 Comparing theory with experiment: geometry 65 3.8 Comparing theory with experiment: molecular properties 68 3.9 Combining theory and experiment 74 4. Nuclear Magnetic Resonance Spectroscopy 79 4.1 Introduction 79 4.2 The nuclear magnetic resonance phenomenon 79 4.3 Experimental set-up 83 4.4 The pulse technique 86 4.5 Information from chemical shifts 92 4.6 Information from NMR signal intensities. 100 4.7 Simple splitting patterns due to coupling between nuclear spins 101 4.8 Information from coupling constants 112 4.9 Notsosimple spectra 116 4.10 The multi-nuclear approach 120 4.11 Multiple resonance 121 4.12 Multipulse methods 126 4.13 Twodimensional NMR spectroscopy 129 4.14 Gases 140 4.15 Liquid crystals 140 4.16 Solids 141 4.17 Monitoring dynamic phenomena and reactions 147 4.18 Paramagnetic compounds 154 5. Electron Paramagnetic Resonance Spectroscopy 169 5.1 The electron paramagnetic resonance experiment 169 5.2 Hyperfine coupling in isotropic systems 171 5.3 Anisotropic systems 175 5.4 Transition-metal complexes 179 5.5 Multiple resonance 182 6. Mossbauer Spectroscopy 189 6.1 Introduction 189 6.2 The Mossbauer effect 189 6.3 Experimental arrangements 192 6.4 Information from Mossbauer spectroscopy 194 6.5 Compound identification 204 6.6 Temperature- and time-dependent effects 208 6.7 Common difficulties encountered in Mossbauer spectroscopy 212 6.8 Further possibilities in Mossbauer spectroscopy 213 7. Rotational Spectra and Rotational Structure 219 7.1 Introduction 219 7.2 The rotation of molecules 219 7.3 Rotational selection rules 224 7.4 Instrumentation 228 7.5 Using the information in a spectrum 229 7.6 Using rotation constants to define molecular structures 232 8. Vibrational Spectroscopy 237 8.1 Introduction 237 8.2 The physical basis; molecular vibrations 237 8.3 Observing molecular vibrations 239 8.4 Effects of phase on spectra 245 8.5 Vibrational spectra and symmetry 248 8.6 Assignment of bands to vibrations 254 8.7 Complete empirical assignment of vibrational spectra 262 8.8 Information from vibrational spectra 263 8.9 Normal coordinate analysis 272 9. Electronic Characterization Techniques 277 9.1 Introduction 277 9.2 Electron energy levels in molecules 278 9.3 Symmetry and molecular orbitals 279 9.4 Photoelectron spectroscopy 281 9.5 Valence excitation spectroscopy 286 9.6 Electronic energy levels and transitions in transition-metal complexes 289 9.7 Circular dichroism 298 10. Diffraction Methods 303 10.1 Introduction 303 10.2 Diffraction of electrons, neutrons and X-rays 304 10.3 Diffraction by gases 308 10.4 Diffraction by liquids 321 10.5 Diffraction by single crystals; symmetry 323 10.6 Diffraction by single crystals; the theoretical basis 329 10.7 Diffraction by single crystals; the experiment. 33

Professor David Rankin School of Chemistry, University of Edinburgh, Scotland Prof. Dr. Norbert W. Mitzel Department for Inorganic Chemistry and Structural Chemistry, Bielefeld University, Germany Dr Carole Morrison School of Chemistry, University of Edinburgh, Scotland

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