Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 190 for “"single crystal X-ray diffraction"”.
-
Optimization Techniques for Phase Retrieval Based on Single-Crystal X-Ray Diffraction Data
… innovative optimization models for phasing crystal structures from X-ray diffraction data. First, an integer minimal principle for quartets and triplets is proposed for initially setting the phases of structure factors that compose a Karle-Hauptman matrix. Initialization in this manner is …
-
Single-crystal X-ray diffraction at extreme conditions in mineral physics and material sciences
Single crystal X-ray diffraction (XRD) is a powerful non-destructive method which allows unambiguously identify crystalline phases, determine a crystal structure (unit cell parameters, a space group, atomic coordinates and atomic occupancies) and, if required, a phase composition. This thesis deals …
-
Low Temperature Single-Crystal X-ray Diffraction on A(1-x)A'xMnO3 (A=La,Eu and A'=Ba,Sr)
… We investigated these materials by single-crystal X-ray diffraction. For La0.815Ba0.185MnO3 the structure was analyzed in the temperature range of 188.9-295K. The temperature of 188.9K has been selected as minimum since the crystal undergoes a first-order structural phase transition …
-
Structural variations of feldspars at high pressure and high temperature
… thesis, high-pressure and high-temperature X-ray diffraction data were collected for feldspars over a range of compositions which has led to the development a structural model that allows one to predict the structural evolution of feldspars at depth in the Earth's crust. Specifically, the …
-
Alkalimetallmanganchalkogenide : Synthese, Struktur und Magnetismus
… synthesised and the structure were determined by single crystal X-Ray-Diffraction. The spin-structures of the compounds K2Mn3S4 and Na6MnS4 were determined by Neutrondiffraction experiments involved by measurements in the dependence of an external magnetic field.
-
Homochiral Crystals for Selective Synthesis
… sulfide ligands and copper(I) halides and their crystal structures were determined by single-crystal X-ray diffraction. The aim was to prepare coordination polymers that crystallize as conglomerates in order to use them in total spontaneous resolution. The anionic and neutral ligands were varied …
-
Synthetic and structural studies of Calix[4]pyrogallolarenes: towards biological applications
… been studied by diffusion NMR spectroscopy and single crystal X-ray diffraction. It has been found that calix nano-capsules can be formed by calix[4]pyrogallolarenes in polar protic solvents when the alkyl chain is substituted with bromine at its terminus. This is speculated to be due to …
-
Crystal engineering of dynamic metal organic frameworks for applications in chromic sensing and capturing of small molecules
Crystal engineering of metal organic frameworks (MOFs) has developed rapidly over the years. This has been fuelled by useful properties endowed by these materials. MOFs present a unique platform to control chemical and physical properties through manipulation of the components that construct these …
-
Prehnite at the Atomic Scale: Al/Si Ordering, Hydrogen Environment, and High-Pressure Behavior
… (Al,Si)O4 and SiO4 tetrahedra alternating with single sheets of AlO4(OH)2 octahedra. To understand the ordering in the structure and differences between various samples of prehnite, single-crystal X-ray diffraction data at ambient conditions were collected on four single crystals of prehnite …
-
Oxidative addition of N-H and O-H bonds to iridium: developing active catalysts for N-H and O-H additions to unsaturates
… spectroscopy, IR spectroscopy, C-H analyses and single crystal x-ray diffraction. Similarly, oxidative addition of the O-H bond of phenol, p-cresol, 3,5-dimethylphenol, and water to [Ir(COD)(PMe₃)₃]CI (la) produces mer-Ir(OR)H(PMe₃)₃C1 (<b>5a-c and 6</b>) which were characterized by ¹H, ³¹P and …
-
Investigation of layered calcium phosphates and related materials for Biomaterial applications
… was performed mainly using powder X ray diffraction with thermogravimetric and fourier transform infrared providing further means of analysis. When possible, single crystal X ray diffraction was also utilised. Investigations were performed on metal alkyl phosphates with strontium …
-
The Chemistry of Some Triosmium Alkylidene and Alkylidyne Cluster Complexes
… ('1)H and ('13)C NMR spectroscopy together with single-crystal X-ray diffraction analyses.
-
Polyoxotitanates and their role in titania sol-gel polymerization
… Ti\sb{18}O\sb{28}H\rbrack (OBu\sp{t})\sb{17}$. A single crystal X-ray diffraction study of its t-BuOH solvate revealed a $\rm Ti\sb{18}O\sb{45}$ metal-oxygen framework having a pentacapped Keggin structure Reaction of the complex with t-amyl alcohol led to the product $\rm\lbrack …
-
Aqueous phase catalysis using mono- and bimetallic transition metal complexes
… resonance spectroscopy, infrared spectroscopy, single crystal X-ray diffraction (for complex 2.14), mass spectrometry, elemental analysis and melting point determinations.
-
Crystal engineering and sorption studies of cyclotriveratrylene and C-methylcalix[4]resorcinarene solvates
Cyclotriveratrylene compounds crystallised from acetonitrile (1) and 2-butanone (4) are shown to be nearly isostructural, resulting in the formation of dimeric capsules, while the compound which crystallised from chloroform (3) results in the formation of layers of cyclotriveratrylene molecules …
-
Baeyer-Villiger Oxidation of 1,7- & 1,9-dibromopentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione
… product was established unequivocally via single crystal X-ray diffraction. Baeyer-Villiger oxidation of 1,9-dibromo-PCU-8,11-dione using ceric ammonium nitrate (CAN) was also performed and afforded a mixture of lactones. Only one of these lactones, which also contained an alkene …
-
Part I. Synthesis of Polyoxoanion Supported Organoactinides. Part Ii. Surface Oxygen Reactivity in Decavanadate
… polyoxoanion to actinide adducts. According to a single crystal X-ray diffraction study of (C(,5)H(,5))(,3)U- (NbW(,5)O(,19))(,2) (n-C(,4)H(,9))(,4)N (,5), IR spectroscopy, and ('17)O NMR spectros- copy, all four adducts contain MW(,5)O(,19)('3-) ligands which coordinate to the metal center as …
-
Trispyrazolylborate and Tetramethylcyclopentadienyl Osmium Chemistry: Toward Methane Coordination Complexes
… and this conclusion has been confirmed by a single-crystal X-ray diffraction experiment. Treatment of [(C5Me 4H)2OsBr]2[Os2Br8] with excess 1,5-cyclooctadiene (cod) in refluxing ethanol gives (C5Me 4H)2Os and [(C5Me4H)2OsBr][Os 2HBr4(cod)2]. An X-ray crystallographic study of the latter …
-
Systematic Studies on the Chelating Ligand Effects of Novel Borafluoronium Ions
… and characterized using NMR spectroscopy and single crystal X-ray diffraction. Further investigations into the coordination of other bisphosphine ligands, such as dppe, rac-BINAP, and Xantphos, resulted in the formation of Lewis adducts rather than the desired borafluoronium ions. The …
Page 1 of 10