Dissertation zur Erlangung des Doktorgrades der Fakult¨at f¨ur Chemie und Pharmazie der Ludwig-Maximilians-Universit¨at M¨unchen From Molecular Building Blocks to Condensed Carbon Nitride Networks: Structure and Reactivity Bettina Valeska Lotsch aus Frankenthal / Pfalz 2006 Erkl¨arung Diese Dissertation wurde im Sinne von § 13 Abs. 3 bzw. 4 der Promotionsordnung vom 29. Januar 1998 von Herrn Prof. Dr. Wolfgang Schnick betreut. Ehrenw¨ortliche Versicherung Diese Dissertation wurde selbstst¨andig, ohne unerlaubte Hilfe erarbeitet. M¨unchen, den 20. 11. 2006 Bettina Valeska Lotsch Dissertation eingereicht am 20. 11. 2006 1. Gutachter: Prof. Dr. Wolfgang Schnick 2. Gutachter: Prof. Dr. J¨urgen Senker M¨undliche Pr¨ufung am 19. 12. 2006 To my parents and sister Acknowledgements First of all, I would like to express my gratitude to Prof. W. Schnick for giving me the op- portunity to work in his group, for the freedom of research paired with continuous advertence and support, and for his stimulating enthusiasm. Without his professional guidance and en- couragement, this thesis would not have become what it is. I am indebted to Prof. J. Senker for introducing me into the “brave new world” of solid-state NMR, for his encouragement to never stop digging deeper, for his conviction that the time issue comes only second, and for his seemingly never ending repertoir of questions, answers, ideas and patience, as well as for being co-referee of this thesis. I am thankful to Prof. T. Bein, Prof. D. Johrendt, Prof. K. Karaghiosoff and Prof. T. M. Klap¨otke for their being available as examiners in my viva-voce. Special thanks go to Dr. Markus D¨oblinger, as well as Lena Seyfarth and Jan Sehnert for a fruitful collaboration and stimulating insights into electron diffraction, solid-state NMR, and the world of theory, respectively. For carrying out innumerous measurements, as well as for the “postprocessing” involved, I would like to thank Sandra Albert, Dr. Sascha Correll, Dr. Markus D¨oblinger, Dagmar Ewald, Dr. Gerd Fischer, Helmut Hartl, Dr. Alexandra Lieb, Prof. Dr. Konstantin Karaghiosoff, Juliane Kechele, Thomas Miller, Christian Minke, Peter Mayer, Dr. Peter Mayer, Dr. Oliver Oeckler, Andreas Sattler and Wolfgang W¨unschheim. In detail, I would like to thank • Dr. Oliver Oeckler for his invaluable advice (both in real and in reciprocal space) and for his particular “challenging” view on things in general, • Dr. J¨orn Schmedt auf der G¨unne and Christian Minke for their assistance and co- operation in all NMR-related matters, • Dr. Barbara J¨urgens for opening up the intriguing playground of C/N chemistry and shifting the focus to the most interesting problems, • Andreas Sattler and Theresa Soltner for their assistance, invaluable discussions and exchange of views on C/N matters and beyond, • my bachelor and research students Lucia Romana Lorenz and Daniel Benker for their participation and support, • Carolin Buhtz for her creative contributions to the electron diffraction investigations and her imperturbable capability to listen and de-dramatize things, • Dr. Alexandra Lieb for keeping company in our “night-lab”, for her unfailing nutritional backup, and for her inspiringly different world outlook – I learned a lot ... • Dr. Ulrich Baisch and Dr. Sascha Correll for their outstanding helpfulness and guidance, • Dr. Alexandra Lieb, Juliane Kechele, Robert Kraut, Dr. Abanti Nag, Rebecca R¨omer and Wolfgang W¨unschheim for their collegiality and for creating a pleasant working- and “biosphere” in laboratory D 2.107, • Wolfgang W¨unschheim for technical support whenever hardware or software of all kinds quit the service, • Richard Betz, Sebastian Braun, Dr. Markus D¨oblinger, Michael G¨obel and Dr. Oliver Oeckler for proof-reading this thesis and for racking their brains for me ... For providing a particularly convenient working atmosphere throughout the last years and for all sorts of technical, scientific and “personal” support, I woud like to thank my – present and past – colleagues Dr. Ulrich Baisch, Constantin Beyer, Sabine Beyer, Daniel Bichler, Cordula Braun, Sascha Correll, Holger Emme, Cora Hecht, Elsbeth Hermanns, Gunther Heymann, Dr. Henning H¨oppe, PD Dr. Hubert Huppertz, Stefanie Jakob, Petra Jakubcova, Friedrich Ka- rau, Juliane Kechele, Johanna Knyrim, Robert Kraut, Dr. Alexandra Lieb, Catrin L¨ohnert, Thomas Miller, Christian Minke, Helen M¨uller, Dr. Abanti Nag, Dr. Oliver Oeckler, Sandro Pagano, Dr. Regina Pocha, Florian Pucher, Stefan Rannabauer, Christoph R¨ohlich, Rebecca R¨omer, Andreas Sattler, Dr. J¨orn Schmedt auf der G¨unne, Christian Schmolke, Stefan Sedl- maier, Jan Sehnert, Lena Seyfarth, Theresa Soltner, Florian Stadler, Dr. Johannes Weber, Wolfgang W¨unschheim and Martin Zeuner. Above all, I am indebted to my parents, my sister and Sebastian, who continuously encouraged and supported me with maximum forbearance and patience. For all what they have done and sacrificed, suffice it to say: Gratitude is one of the least articulate of the emotions, especially when it is deep. Felix Frankfurter Be not afraid of growing slowly, be afraid only of standing still. Chinese Proverb Contents 1 Introduction 15 2 Experimental Methods 22 2.1PreparativeMethods................................. 22 2.1.1 VacuumandInertGasLine......................... 22 2.1.2 Furnaces.................................... 22 2.1.3 GloveBox................................... 23 2.1.4 OperatingTechniques............................ 23 2.2AnalyticalMethods.................................. 24 2.2.1 DiffractionTechniques............................ 24 2.2.2 SpectroscopicMethods............................ 30 2.2.3 ElementalAnalysis.............................. 36 2.2.4 MassSpectrometry.............................. 37 2.2.5 ThermalAnalysis............................... 37 3 Theoretical Basis and Models 38 3.1DynamicalProcesses................................. 38 3.2NeutronScattering.................................. 41 3.2.1 BasicPrinciples................................ 41 3.2.2 Diffraction.................................. 43 3.2.3 QuasielasticNeutronScattering(QENS).................. 44 3.2.4 MotionalModels............................... 46 3.2.5 EISF...................................... 47 3.3MagneticResonance................................. 48 3.3.1 BasicPrinciples................................ 48 3.3.2 InteractionHamiltoniansandOperatorFormalism............ 50 3.3.3 High-ResolutionNMR:GeneralAspectsandTechniques......... 63 10 CONTENTS CONTENTS 4 Dynamics and Reactivity 69 4.1 Ammonium Dicyanamide . ............................ 71 4.1.1 Introduction................................. 71 4.1.2 Solid-StateNMR............................... 73 4.1.3 NeutronScattering.............................. 90 4.2 Ammonium Cyanoureate . ............................105 4.2.1 Introduction.................................105 4.2.2 CrystalStructure...............................105 4.2.3 ThermalReactivity..............................110 4.2.4 Cyanoguanylurea...............................121 5CNx Precursors 128 5.1Dicyanamides.....................................130 5.2GuanidiniumDicyanamide..............................135 5.2.1 Introduction.................................135 5.2.2 CrystalStructures..............................135 5.2.3 VibrationalSpectroscopy..........................141 5.2.4 ThermalBehavior..............................143 5.3MelaminiumDicyanamide..............................148 5.3.1 Introduction.................................148 5.3.2 CrystalStructure...............................148 5.3.3 ThermalBehavior..............................151 5.3.4 Temperature-DependentFTIRSpectroscopy...............153 5.3.5 Discussion...................................155 5.4GuanylureaDicyanamide..............................157 5.4.1 Introduction.................................157 5.4.2 CrystalStructure...............................157 5.4.3 SpectroscopicCharacterization.......................159 5.4.4 ThermalBehavior..............................160 5.5Tricyanomelaminates.................................167 5.6Non-MetalTricyanomelaminates..........................170 5.6.1 CrystalStructuresandSpectroscopicCharacterization..........170 5.6.2 ThermalBehavior..............................185 5.6.3 DSC and In Situ X-RayDiffraction....................186 5.6.4 IRSpectroscopy...............................188 5.6.5 Solid-StateNMR...............................191 11 CONTENTS CONTENTS 5.6.6 Discussion...................................192 5.7PreliminaryConclusion...............................193 6Melam 196 6.1Introduction......................................197 6.2ThermalBehaviorofMelamine...........................200 6.3 Adduct Phases . ...................................203 6.3.1 MassSpectrometry..............................203 6.3.2 ElementalAnalysis..............................204 6.3.3 IRSpectroscopy...............................205 6.3.4 NMRSpectroscopy..............................206 6.3.5 ThermalAnalysis...............................212 6.4Melam.........................................213 6.4.1 IRSpectroscopyI:Formation........................215 6.4.2 AnalyticalData................................216 6.4.3 CrystalStructure...............................216 6.4.4 IRSpectroscopyII:Structure........................218 6.4.5 Solid-StateNMRSpectroscopy.......................218 6.4.6 ThermalBehavior..............................221 6.4.7 UV/VisSpectroscopy............................222 6.4.8 Discussion...................................224 6.5MelamDerivatives..................................226