In this thesis, 60 crystal structures which have been synthesised by the solvothermal method are reported, with 57 of them representing novel materials. The remaining three materials have previously been reported but have been made by a new and milder method of synthesis. Ti, Zr, Hf, V, Nb, Ta and Mo have all been used to make fluoride or oxyfluoride materials at temperatures ranging from 60C to 200C. Both inorganic and organic moieties ("templates") have been used to direct the formation of the (oxy)fluoride materials, usually as an anionic species. These materials have then been studied for their magnetic properties, where relevant. Initially, 10 vanadium-based compounds were made at 100C using a range of templates. Through variations in water content, temperature and cation ratio, a further 19 compounds were synthesised. The inorganic species in these structures ranged from monomers, to dimers, tetramers and chains, to infinite 2D sheets. A family of vanadium compounds has been synthesised, with piperazine as a template, which shows an increase in covalent connectivity through the increase of the reaction temperature, with a decrease in oxidation state as a result. These materials are also interrelated through the use of a "Y" shaped motif in their structural composition. Through a change in cation content a novel trigonal chain compound (related to the structure of CsCrF₄) has been synthesised with piperazine which possibly shows strong geometric frustration. Vanadium oxyfluoride analogues of (VO)₂P₂O₇ have been made, which show interesting magnetic properties with a range of different templates, ranging from alkali metal cations to the bulky protonated template trans 1,2 bis (4-pyridyl) ethene. The best fits to the magnetic susceptibility data are obtained with an antiferromagnetic Heisenberg chain model. Nine molybdenum-based structures have also been synthesised, with five of the structures being made through changes in the temperature and cation ratio of the reactions. An example of this is the formation of tetrameric units with ammonium, through the condensation of monomers as a result of an increase in the reaction temperature. A further 22 structures have also been made with metals, M = Ti, Zr, Hf, Nb and Ta. These structures have a tendency to form isolated polyhedral units under the conditions studied in this work. Several examples of isolated [MF₆][superscript n-] and [MF₇][superscript n-] monomers are reported and also one example of a trans-connected [TiOF₄]²⁻ infinite chain structure.

An exploration of some early transition metal (oxy) fluoride systems using solvothermal techniques has been carried out. 30 novel materials have been synthesised, which fall into three classes based on different metal centres; vanadium (21), molybdenum (5) and niobium (4). Some of these also contain secondary metal centres, namely copper (22) and zinc (1). Simultaneously, the relationship between the SHG values and the crystal structures of the hilgardites family members Pb₂B₅O₉Cl, Pb₂B₅O₉Br, Sr₂B₅O₉Cl and Ba₂B₅O₉Cl was investigated. In particular, the Pb–containing members of the hilgardite family of borate halides exhibit an abnormally large non–linear optical response, which was analysed based on neutron powder diffraction. Using solvothermal synthesis in HF–containing media, 21 novel vanadium oxyfluorides containing interesting structural features, were synthesised at 160˚C using a range of organo-amine compounds as a ligand, template, linker or structure directing agent. The architectures of the crystal structures may be categorised into; four clusters including monomeric vanadium units, five clusters including vanadium dimers, eight 1–D chains, two 2–D layers and two 3–D networks. ‘Composition–space’ diagrams with three components were used to study the effect of stoichiometry changes of reactants and to map out the crystallisation fields. The combination of early (Nb⁵⁺, Mo⁶⁺) and late (Cu²⁺) transition metals with different organo-amines produced nine novel compounds incorporating monomers, chains and 2– D interpenetrated networks. The chains and layers were synthesised from a systematic series of reactions at 160˚C and can be subdivided into four pairs, the topologies of which are essentially unique to each ligand, containing in each case a Cu–based cationic species, but alternately either [MoO₂F₄]²⁻ or [NbOF₅]²⁻, in an isomorphous manner, as the anionic moiety. The overall structures of these materials reflect the influence of the organo–amine ligands. The materials have been studied for their magnetic properties and characterised by thermogravimetric analysis, Rietveld refinement and elemental analysis where relevant.

Carbon-13 nuclear magnetic resonance is a very useful spectroscopic technique in studying organic compounds, especially when the proton NMR does not provide much information. In this study of multicyclic lactams, different NMR techniques were used: broadband decoupled spectra, single-frequency off-resonance decoupling (SFORD), and the attached proton test (APT). Lanthanide shift reagents and lanthanide relaxation reagents were also used. Almost all the carbon-13 resonances of mono-, bi-, and polycyclolactams were unambiguously assigned. The most powerful method in the assignments was based on the use of the lanthanide induced shifts (LIS) which confirmed the assignments qualitatively and quantitatively. The quantitative confirmation comes from the calculations of LIS and their comparison with the observed shifts. The carbon-13 chemical shielding of the studied lactams was analyzed and compared with analogous compounds. The results presented provide a consistent picture and the major influences in the trends of the ¹³C chemical shifts. However, no empirical relationships were derived for this series of compounds. The solution conformations of most of these lactams have been investigated using the shifts induced in their carbon-13 NMR by Yb(dpm)₃. These conformations were compared with structures obtained from X-ray data and MINDO/3 calculations. The structural analyses of ε-caprolactam and 3-azabicyclo[4.3.1]decan-4-one showed that these molecules have at least two conformations in solution. The LIS structural analyses were confirmed by using ¹³C T₁ relaxation times in Gd(dpm)₃ and Gd(fod)₃ relaxation reagents. The different contributions to the ¹³C NMR lanthanide induced shifts (LIS) were studied with emphasis in determining the importance of the ligand pseudocontact contribution. This was found to be important, especially in carbons in proximity to the complexation site.

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The main goal of the present work was the synthesis of alkaline-earth nitridomanganates (AExMnyNz) with extended anionic structures and the characterization of their electronic and magnetic properties. Up to now, only compounds with isolated nitridomanganate anions have been reported in the discussed ternary systems. A systematic exploratory synthesis, employing high-temperature treatment of AE nitrides and Mn under controlled N2 pressure, yielded more than ten new nitridomanganates. Their crystal structures contain anionic building blocks of different dimensionalities, ranging from isolated species to three-dimensional frameworks. In general, the formation of Mn-rich compositions was found to be driven by the emergence of Mn-Mn interactions, which creates a link between nitridometalates and transition-metal-rich binary nitrides. The obtained nitridomanganates display a plethora of interesting phenomena, such as large spin-orbit coupling, magnetic frustration, quenching of magnetism due to Mn-Mn interactions, and metal-insulator transition.

Charge transfer salts of Tetracyanoquinodimethane (TCNQ) were synthesised and their electrical and magnetic properties were investigated. These salts show unusual electrical and magnetic behaviour in contrast to conventional organic compounds. These salts have crystal structures which in general consist of TCNQ radical ions stacked in chains, isolated from each other by the diamagnetic cations. They are thus regarded as "one-dimensional" electrical and magnetic systems. The ESR spectra of these salts are attributed to triplet excitons showing that the spin-spin and electronelectron correlation effects are important. In the ESR spectra (Chapter III) of some TCNQ salts dipolar splitting is observed confirming the spin-spin interaction. These triplet excitons are regarded as bound electron-hole pairs. The experimentally determined dipolar splitting tensors are presented in Chapter III and the intensity data in Chapter IV. A large number of fine structure lines are observed in the ESR spectra of Pyridinium-TCNQ and 4-Aminopyridinium-TCNQ apart from regular triplet exciton lines (Chapter III). These lines are attributed to the trapping of excitons on an extended formula finit (TCNQ2 )n. In Chapter IV the temperature dependent magnetic susceptibilities are discussed in terms of Heisenberg antiferromagnetism and Pauli paramagnetism. In Chapter V temperature dependent behaviour of electrical conductivity is discussed in terms of an exciton band model, the lattice structure of the salts and one-dimensional lattice consisting of defects giving rise to high and low conducting segments. Low temperature electrical and magnetic phases are discussed (Chapters IV and VII) in terms of a band and hopping mechanisms.In Chapter VI self consistent field calculations are made with reference to the tight binding one electron band theory using simplified Roothaan equations considering CNDO approximations. Theoretical results are related to experimental band gaps, spinspin interactions and charge alteration.