Abstract The present thesis deals with the nuclear magnetic resonance (NMR) spectroscopy of small solutes applied to the studies of liquid crystals and molecular sieves. In this method, changes induced by the investigated environment to the static spectral parameters (i.e. nuclear shielding, indirect and direct spin-spin coupling and quadrupole coupling) of the solute are measured. The nuclear shielding of dissolved noble gases is utilized for the studies of thermotropic liquid crystals. The relation between the symmetry properties of mesophases and the nuclear shielding is described. The different interaction mechanisms perturbing the observed noble gas nuclear shielding are discussed, particularly, the role of long-range attractive van der Waals interactions is brought out. The suitability of the noble gas NMR spectroscopy to the studies of lyotropic liquid crystals is investigated in terms of nuclear shielding and quadrupole coupling interactions. In molecular sieve systems, the effect of inter- and intracrystalline motions of solutes on their NMR spectra is discussed. A novel method for the measurement of the intracrystalline motions is developed. The distinctions in the 13C shielding of methane adsorbed in AlPO4-11 and SAPO-11, two structurally similar molecular sieves differing in composition, are indicated.

Examinations of the effects of (a.) alkyl carbon chain length and (b.) perfluorination of acyl chlorides; propionyl chloride, butyryl chloride, valeroyl chloride, and perfluorinated acyl chlorides; perfluoropropionyl chloride and perfluorobutyryl chloride, are reported and compared using CP-FTMW spectroscopy. All of these molecules are already published in various journals except for valeroyl chloride. The chapters are organized by molecule alkyl chain length and include some background theory. Conformational stability, internal rotation, helicity, and ionic character of the C-Cl bond via the nuclear electric quadrupole coupling constant (χzz) are analyzed. Results show syn, syn-anti/syn-gauche, and syn-anti-anti/syn-gauche-anti stable conformations. Internal rotation was only seen in propionyl chloride. Helicity was not observed. (χzz) was observed to be inert to alkyl chain length, ~ 60 MHz and ~ 65 MHz for the nonfluorinated and fluorinated acyl chlorides. Partial fluorination and varying functional groups are recommended.

Abstract In this thesis nuclear magnetic resonance (NMR) and magneto-optical rotation (MOR) parameters are investigated for water, paying special attention to the effect of solvation from gaseous to liquid phase. Nuclear magnetic shielding and quadrupole coupling tensors of NMR spectroscopy are studied for gaseous and liquid water. Liquid state is modelled by a 32-molecule Car-Parrinello molecular dynamics simulation, followed by property calculations for the central molecules in clusters cut out from the simulation trajectory. Gaseous state is similarly represented by a one-molecule simulation. Gas-to-liquid shifts for shielding constants obtained this way are in good agreement with experiments. To get insight into the local environment and its effect on the properties the clusters are divided into groups of distinct local features, namely the number of hydrogen bonds. The analysis shows in detail how the NMR tensors evolve as the environment changes gradually from the gas to liquid upon increasing the number of hydrogen bonds to the molecule of interest. The study sheds light on the usefulness of NMR experiments in investigating the local coordination of liquid water. To go a bit further, the above mentioned NMR parameters along with the spin-spin coupling constant are examined for water dimer in various geometries to have insight into solvation and hydrogen bonding phenomena from bottom to top. Characteristic changes in the properties are monitored as the geometry of the dimer is systematically varied from very close encounter of the monomers to distances and orientations where hydrogen bonding between monomers ceases to exist. No rapid changes during the hydrogen bond breaking are observed indicating that the hydrogen bonding is a continuous phenomenon rather than an on-off situation. However, for analysis purposes we provide an NMR-based hydrogen bond definition, expressed geometrically, based on the behaviour of the NMR properties as a function of dimer geometry. Our definition closely resembles widely used definitions and thus reinforces their validity. Magneto-optical rotation parameters, the nuclear spin optical rotation (NSOR) and the Verdet constant, are computed for gaseous and liquid water, in the same manner as the NMR properties above. Recent pioneering experiments including NSOR for hydrogen nuclei in liquid water and liquid xenon have demonstrated that this technique has a potential to be a useful new probe of molecular structure. We reproduce computationally, applying a first-principles theory developed recently in the group, the experimental NSOR for hydrogen nuclei in liquid water, and predict hydrogen NSOR in gaseous water along with the oxygen NSOR in liquid and gaseous water. NSOR is an emerging experimental technique that needs interplay between theory and computation for validation, steering and insight.

Abstract In this thesis, the theory of static magnetic resonance spectral parameters of nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy is investigated in terms of the molecular Breit-Pauli Hamiltonian, which is obtained from the relativistic Dirac equation via the Foldy-Wouthuysen transformation. A leading-order perturbational relativistic theory of NMR nuclear shielding and spin-spin coupling tensors, and ESR electronic g-tensor, is presented. In addition, the possibility of external magnetic-field dependency of NMR parameters is discussed. Various first-principles methods of electronic structure theory and the role of one-electron basis sets and their performance in magnetic resonance properties in terms of their completeness profiles are discussed. The presented leading-order perturbational relativistic theories of NMR nuclear shielding tensors and ESR electronic g-tensors, as well as the theory of the magnetic-field dependent NMR shielding and quadrupole coupling are evaluated using first-principles wave function and density-functional theories.

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