Structure determination of powdered crystals is still not a trivial task. For gas hydrates, the difficulty lies in how to determine the rotational disorder and cage occupancies of the guest molecules without other supporting information or constraints because the complexity of the problem for the powder diffraction technique generally depends on the number of atoms to be located in the asymmetric unit. Here, the crystal structures of gas hydrates of CO2, C2H6, C3H8, and Methylcyclohexane/CH4, as determined by the direct-space and Rietveld techniques are reported. The resultant structures and cage occupancies were consistent with results found from conventional experimental methods using single crystal x-ray diffraction or solid-state 13C-NMR. It was shown that the procedures reported in this study make it possible to determine guest disorder and absolute cage occupancy of gas hydrates even from powder crystal.

Li-O2 batteries have been attracting increasing attention and R&D efforts as promising power sources for electric vehicles (EVs) due to their significantly higher theoretical energy densities compared to conventional Li-ion batteries. The research presented in this thesis covers the investigation of factors influencing the decomposition of Li2O2, the development of highly active electrocatalysts, and the design of low-cost and easy-operation binder-free O2 electrodes for Li-O2 batteries. Being the main technique, SR-PXD was used both as a continuous light source to advance the electrochemical decomposition of Li2O2 under the X-ray illumination and an operando tool that allowed us to probe the degradation of Li2O2. Since XRD was intensively used in my thesis work, the effect of X-ray irradiation on the stability of Li2O2 was studied. The accelerating effect of X-rays on the electrochemical decomposition of Li2O2 was, for the first time, explored. The electrochemical decomposition rate of Li2O2 was proportional to the X-ray intensity used. It is proposed that the decomposition might involve a three-step reaction with [Li2O2]x+ and Li2-xO2* as intermediates, which followed pseudo-zero-order kinetics. Then, three electrocatalysts (Pt/MNT, Ru/MNT and Li2C8H2O6) were developed, which exhibited good electrocatalytic performances during the OER. Their activities were evaluated by following the Li2O2 decomposition in electrodes during the charging processes. In addition, the time-resolved OER kinetics for the electrocatalyst-containing Li-O2 cells charged galvanostatically and potentiostatically was systematically investigated using operando SR-PXD. It was found that a small amount of Pt or Ru decoration on the MNTs enhanced the OER efficiency in a Li-O2 cell. The Li2O2 decomposition of an electrode with 5 wt% Pt/MNT, 2 wt% Ru/MNT or Li2C8H2O6 in a Li-O2 cell followed pseudo-zero-order kinetics. Finally, a novel binder-free NCPE for Li-O2 batteries was presented. It displayed a bird’s nest microstructure, which could provide the self-standing electrode with considerable mechanic durability, fast O2 diffusion and enough space for the discharge product deposition. The NCPE contained N-containing functional groups, which may promote the electrochemical reactions.

This work investigated the synthesis, characterisation and properties of known and novel scandium carboxylate Metal-organic Frameworks (MOFs). The first part reports the performance of these Sc-MOFs as Lewis acid catalysts. The porous MOF scandium trimesate MIL-100(Sc) and the scandium terephthalates such as MIL-101(Sc), MIL-88B(Sc) and MIL-68(Sc) (prepared as the Sc-analogue for the first time), and scandium biphenyldicarboxylate MIL-88D(Sc) were prepared and tested as Lewis acid catalysts. Chromium MIL-101 and MIL-100 and scandium-exchanged zeolites were prepared for comparison. Moreover, successful encapsulation of the phosphotungstate polyoxometalates (POMs) in the cavities of MIL-101(Sc) enhanced the stability of this material. These scandium and chromium MOFs, POM-MOF composites and scandium-exchanged zeolite were tested as heterogeneous catalysts in the carbonyl ene reaction between α-methyl styrene and ethyl trifluoropyruvate. This showed that MIL-100(Sc) was the best catalyst for this reaction, achieving a conversion of 99% to the desired product. The stabilized MIL-101(Sc) was also very active, but less selective for this reaction. Acetalisation of acetaldehyde was also studied, and in this reaction the isoreticular MOFs MIL-88(B) and MIL-88D(Sc) were the most active and selective catalysts. For this reaction, the activity of MIL-100(Sc) was low, which was attributed to reduce pore size and blockage. Functionalisation of the range of scandium terephthalates such as MIL-101(Sc), MIL-88B(Sc), MIL-68(Sc), Sc₂BDC₃,and MIL-53(Sc) particularly with –NH₂ groups, made up the second main part of this research. Solvothermal synthesis were performed at lower temperatures and using mixed solvents to synthesize these amino-terephthalate MOFs, often for the first time, and their adsorption properties were studied, particularly for the adsorption of CO₂. The synthesis of pure Sc₂(NH₂-BDC)₃ and Sc₂(Br-BDC)₃ was achieved for first time by a solvothermal route, lower temperatures, and mixed solvents. This approach yielded large crystals suitable for single crystal diffraction and microcrystal IR spectroscopy. Post-synthetic modification (PSM) of Sc₂(NH₂-BDC)₃ was explored by incorporation of NO₂-groups into the framework by solvent-assisted ligand exchange. The adsorption properties of functionalised and post-modified materials were compared with those of Sc₂BDC₃ and Sc₂(NO₂-BDC)₃ for methanol and hydrocarbons This study demonstrated that Sc₂BDC₃ and Sc₂(NH₂-BDC)₃ give the higher uptakes while the –Br and –NO₂ forms display shape selectivity for n-alkanes over iso-alkanes. Amino-functionalised MIL-53(Sc) was prepared for the first time using a mixed ligand approach, so that 10-20% of a second functionalised terephthalate ligand (NO₂, Br, -(OH)₂) was required for successful single phase synthesis in addition to amino-terephthalic acid. The materials were characterised using PXRD, TGA and gas adsorption, which confirms the samples show a range of behaviour for CO₂ adsorption. Notably, the `breathing´ behaviour is strongly dependent on the type of functionalisation. Finally, the exploratory synthesis of novel scandium MOFs, using isophthalic acid (IA) and its amino and nitro- derivatives, 2,5-furandicarboxylate (FDA) and the porphyrin tetra(carboxyphenyl)porphyrin (TCPP) as linkers was carried out and six novel materials were synthesized, three of which gave crystals large enough for their structure to be determined by single crystal diffraction. Further characterisation was carried out by PXRD, TGA and solid-state NMR. Some of these materials have been shown to be porous to CO₂ and N₂.

Small quantities of amorphous content can have a profound influence on the properties of a material, however their instability means that quantifying amorphous content over time is important for proving the stability of a drug. Quantifying amorphous content in α-lactose monohydrate by solid state 13C CP MAS NMR, has been carried out by use of proton saturation recovery relaxation and differentiating between spectra by partial least squares (PLS), however these techniques have not proved sensitive on their own, this work investigates their sensitivity in combination. Crystalline α-lactose monohydrate and a rapidly quenched melt were combined to create a set of calibration mixes, whose spectra were recorded using proton saturation recovery relaxations ranging from 2 to 60 seconds. This technique showed a limit of detection of 0.17% (LOD = intercept + 3xSy/x), with a relaxation delay of 15 s and was able to recognise amorphous materials generated by spray and freeze drying. The atmospheric effects on the proton saturation recovery relaxation times of different amorphous lactose preparations were investigated. This found that an oxygen atmosphere reduced the relaxation times, of amorphous lactose that was prepared from a rapidly quenched melt. The loss of moisture from spray dried and freeze dried samples to less than 1% removed the significance of this effect. Lactose is an important excipient in pharmaceuticals and a key ingredient of confectionary, very little research has been carried out in to the quantification of the isomers of different preparations of amorphous lactose. This work quantifies the isomer content by Gas Chromatography with Flame Ionisation Detection (GC-FID) using a DB-17 15m 0.53mm 1.00 μm column and derivatisation with N- (trimethylsilyl)imidazole.

Novel open-framework germanates and vanadoborates, which are constructed from typical types of clusters, have been synthesized based on different strategies. The crystal structures are solved by using single crystal X-ray diffraction (SXRD) technique or by combined techniques. Additionally, the structures of two open-framework materials, PKU-3 and PKU-16, are determined from nano-sized crystals by rotation electron diffraction (RED) combined with powder X-ray diffraction (PXRD). This thesis serves as an introduction to synthesis of open-framework germanates and vanadoborates based on different design strategies. Two germanates are obtained; SU-74 is achieved by employing a novel structure directing agent (SDA), SUT-8 is achieved by assembling the novel structure building units (SBUs) of Co@Ge14 with the introduction of cobalt ions in the synthesis. Four strategies are successfully used in construction of open-framework vanadoborates: using metal-oxo polyhedra as the linkages in SUT-6; applying the scale chemistry approach in SUT-7; employing metal-organic complexes as the linkages in SUT-12, SUT-13, SUT-14; and introducing covalent bond organic linkages into SUT-10 and SUT-11. Single crystal X-ray diffraction is used to conduct the structure determination in combination with other techniques. Furthermore, the structures of two open-framework materials, an aluminoborate PKU-3 and a germanosilicate PKU-16, are solved from nano-sized crystals using RED data. The structures are further confirmed by Rietveld refinement against PXRD data. The advantages of the RED techniques are demonstrated in two aspects. In PKU-3, the presence of seriously preferred orientation and light elements in the structure makes it difficult for structure determination by PXRD, but it is easier by RED. In PKU-16, the RED technique is used to determine its structure from the as-synthesized multi-phasic sample containing nano-sized crystals. After the structure of PKU-16 has been solved, the synthesis of this interesting phase can be optimized and pure PKU-16 can be obtained. Keywords: Open-framework, germanates, vanadoborates, aluminoborates, germanosilicates, crystal structure, hydrothermal synthesis, single crystal X-ray diffraction, rotation electron diffraction, powder X-ray diffraction

In this work, in-depth structural and electrical characterisation is used to study a family of “empty” tetragonal tungsten bronzes (TTBs), A2₄A1₂B1₂B2₈O₃₀. An initial investigation into the effect of the A1-cation size on the properties of empty Ba₄R₀.₆₇◻₁.₃₃Nb₁₀O₃₀ TTBs (where R is the A1-cation and R = La, Nd, Sm, Gd, Dy and Y; ◻ = vacancy) was performed. These were determined to be metrically tetragonal by powder x-ray diffraction, with decreasing R cation size inducing increased crystal anisotropy. This tetragonal structural distortion, driven by contraction in the ab-plane, is shown to stabilise c-axis ferroelectricity; a direct correlation between tetragonality and the ferroelectric Curie temperature, T[sub]C, is demonstrated. Further examination of the relaxor ferroelectric (RFE) to ferroelectric (FE) crossover in Ba₄(La₁₋ₓNdₓ)₀.₆₇◻₁.₃₃Nb₁₀O₃₀ TTBs using detailed structural studies employing variable temperature, high resolution neutron, synchrotron X-ray and electron diffraction revealed a common superstructure with 2√2 × √2 × 2 cell with respect to the basic tetragonal aristotype cell. However, they display different degrees of order/disorder which can disrupt polar order (ferroelectricity). La-rich analogues exhibit a disordered regime between the low and high temperature ferroelectric and non-polar phases. Although polar, this disordered regime is non-ferroelectric, however, large polarisation may be established with an applied electric field, but relaxes back to the disordered phase upon removal of the field. Substitution of Nd for La at the A1-site leads to destabilisation of the disordered phase and reintroduces “normal” ferroelectric behaviour. Finally, isovalent substitution of Sr²⁺∙ for Ba²⁺ is shown to lead to the development of relaxor behaviour at higher dopant concentrations in Ba₄₋ₓSrₓDy₀.₆₇◻₁.₃₃Nb₁₀O₃₀, (x = 0, 0.25, 0.5, 1, 2, 3; ◻ = vacancy). With increasing x the unit cell contracts in both the ab- plane and c-axis coinciding with a decrease in T[sub]C and development of relaxor behaviour for x ≥ 2. This observation is rationalised by differing cation occupancies: for x ≤ 1, Sr²⁺ principally occupies the A2-site while for x ≥ 2 significant Sr²⁺ occupation of the A1-site leads to the observed RFE characteristics. The FE to RFE crossover is discussed in the context of a previously proposed TTB crystal chemical framework with the A1-site tolerance factor identified as the dominant influence on relaxor behaviour.

Dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate was introduced into the chemically stable UiO-66 structure by a postsynthetic linker exchange reaction to create an optical sensor material for the detection of oxidative agents such as nitrous gases. The incorporated tetrazine unit can be reversibly oxidized and reduced, which is accompanied by a drastic colour change from yellow to pink and vice versa. The high stability of the framework during redox reaction was proven by powder X-ray diffraction and nitrogen physisorption measurements.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21129号 / 工博第4493号 / 新制||工||1698(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 宮原 稔, 教授 山本 量一, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p>The overall time and cost for a drug to go from the drug discovery to the consumer market is  significant,  showing  a  need  for  improved  drug  testing  and  discovery  methods.    Work  on nonlinear  optical  methods  for  both  small  active  pharmaceutical  ingredient  drug  formulation analysis and large biological therapeutic stability testing has been shown to improve testing times for formulation, stability and dissolution testing.  Herein, we review the existing and conventional approaches to address stability testing that the pharmaceutical industry uses, and how leveraging nonlinear optical (NLO) methods can improve the current challenges.  The specificity, sensitivity and low limit of detection of second harmonic generation is discussed in application to crystal formation in small-molecule active pharmaceutical ingredients.  The nonlinear optical methods second harmonic generation and two-photon excited ultraviolet fluorescence are directly compared to  ‘gold  standard’  powder  X-ray  diffraction,  which  is  commonly  used  for  measuring  crystal formation and growth of active pharmaceutical ingredients in amorphous solid dispersions.  In addition, the existing FRAP method (with multiple limitations) is improved upon with the ability to  perform  recovered  diffusion  coefficient  data  analysis  in  the  spatial  Fourier  domain.    The collective results discussed in this thesis are just a small subset of the total breadth of investigations marrying the new challenges in the pharmaceutical industry with the new NLO tools tailored to meet them</p>

Photoelectrodes and photovoltaic devices have been prepared via multiple thin film deposition methods. Aerosol assisted chemical vapour deposition (AACVD), electrodeposition (ED), chemical bath deposition (CBD) and doctor blade technique (DB) have been used to deposit binary and ternary metal oxide films on FTO glass substrates. The prepared thin films were characterised by a combination of SEM (Scanning Electron Microscopy), powder X-ray diffraction, mechanical strength tests and photochemical measurements. Nickel oxide (NiO) thin films prepared by AACVD were determined to have good mechanical strength . with a photocurrent of 7.6 μA cm-2 at 0 V and an onset potential of about 0.10 V. This contrasted with the dark current density of 0.3 μA cm-2 at 0 V. These NiO samples have very high porosity with crystalline columns evidenced by SEM. In comparison with the AACVD methodology, NiO films prepared using a combination of ED and DB show good mechanical strength but a higher photocurrent of 24 μA cm-2 at 0 V and an onset potential of about 0.10 V with a significantly greater dark current density of 7 μA cm-2 at 0 V. The characteristic features shown in the SEM are smaller pores compared to the AACVD method. Copper (II) oxide (CuO) and copper (I) oxide (Cu2O) films were fabricated by AACVD by varying the annealing temperature between 100-325°C in air using a fixed annealing time of 30 min. It was shown by photocurrent density (J-V) measurements that CuO produced at 325 °C was most stable and provided the highest photocurrent of 173 μA cm-2 at 0 V with an onset potential of about 0.23 V. The alignment of zinc oxide (ZnO) nano-rods and nano-tubes fabricated by CBD have been shown to be strongly affected by the seed layer on the FTO substrate. SEM images showed that AACVD provided the best seed layer for aligning the growth of the nano-rods perpendicular to the surface. Nano-rods were successfully altered into nano-tubes using a potassium chloride bath etching method. NiO prepared by both AACVD and the combined ED/DB method were sensitized to absorb more of the solar spectrum using AACVD to deposit CuO over the NiO. A large increase in the photocurrent was observed for the p-type photoelectrode. These p-type photoelectrode showed a photocurrent density of approximately 100 μA cm-2 at 0 V and an onset potential of 0.3 V. This photocathode was then used as a base to produce a solid state p-type solar cell. For the construction of the solid state solar cells several n-type semiconductors were used, these were ZnO, WO3 and BiVO4. WO3 and BiVO4 were successfully produced with BiVO4 proving to be the optimum choice. This cell was then studied more in depth and optimised by controlling the thickness of each layer and annealing temperatures. The best solid state solar cell produced had a Jsc of 0.541 μA cm-2 (541 nA) and a Voc of 0.14 V, TX146 made up of NiO 20 min, CuFe2O4 50 min, CuO 10 min, BiVO4 27 min, using AACVD and then annealed for 30 min at 600°C.