Jukka Jokisaari | University of Oulu (original) (raw)

Papers by Jukka Jokisaari

Molecular Physics, Feb 20, 1984

ABSTRACT

Springer eBooks, 1990

A special method is described to simplify the analysis of the NMR spectral parameters of partiall... more A special method is described to simplify the analysis of the NMR spectral parameters of partially oriented molecules, so as to make seemingly underdetermined problems solvable. The method is applied to the anisotropic couplings Dij of acetonitrile oriented in various liquid crystals.

Chemischer Informationsdienst, Feb 18, 1975

Molecular Physics, Aug 10, 1986

The 125Te N.M.R. spectrum of tellurophene in three liquid crystals was recorded and analysed. The... more The 125Te N.M.R. spectrum of tellurophene in three liquid crystals was recorded and analysed. The different orientational behaviour of tellurophene in the liquid crystals enabled the anisotropy of the tellurium-125 shielding tensor, sigmazz - 1/2(sigmaxx + sigmayy), and the difference sigmaxx - sigmayy of the tensor elements to be determined. The resulting values are -1569 ± 21 ppm and 307 ± 26 ppm, respectively. The analysis of the 125Te N.M.R. spectra is also discussed.

Journal of Molecular Structure, Oct 1, 1983

The rc~-structure of pyrrole-' sN dissolved in three nematic liquid crystals has been determined ... more The rc~-structure of pyrrole-' sN dissolved in three nematic liquid crystals has been determined by using linear combinations of the dipolar H-H,~N-H and~:C-H coupling constants_ The observed deviations between the structures, the large chemical shift variations and the behavior of the order tensor elements are interpreted as a consequence of hydrogen bonding between the pyrrole and liquid crystal molecules.

Springer eBooks, 2003

ABSTRACT Interestingly, the first results of the 129Xe NMR experiments were published as early as... more ABSTRACT Interestingly, the first results of the 129Xe NMR experiments were published as early as 1951 when Proctor and Yu [1] reported the magnetic moment of the isotope. One can regard the experiment by Loewenstein and Brenman in 1978 [2] as the starting point of the application of xenon NMR to the investigation of liquid-crystalline systems. They were the first, to the author’s knowledge, to record the 131Xe NMR spectrum of xenon in a liquid-crystalline environment, a lyotropic liquid crystal composed of poly-γ-benzyl-L-glutamate (PBLG) and chloroform. This work will be discussed in section 4. A huge growth of interest in 129Xe NMR spectroscopy emerged in the 1980s when its use was suggested for deriving information on pore size in microporous materials, such as zeolites and molecular sieves. The first 129Xe NMR experiments on xenon in a thermotropic liquid crystal were performed in 1988 by Bayle et al. [3]. Several review articles have been published on Xe NMR, the most comprehensive being that by Ratcliffe [4] which covers various applications. The review by Bonardet et al. concentrates on 129Xe NMR of porous solids [5], and the one by Jokisaari deals with NMR of noble gases in isotropic liquids and liquid crystals [6].

The Ne-21 QC (Quadrupole Coupling) was studied over the temperature range 305 to 352 K in the liq... more The Ne-21 QC (Quadrupole Coupling) was studied over the temperature range 305 to 352 K in the liquid crystal Merck ZLI 1167. The results indicate that the total EFG (Electric Field Gradient) experienced by the isotope must be a sum of at least two contributions. The comparison of the EFG's derived in similar environments by Xe-131, Kr-83, and Ne-21 NMR (Nuclear Magnetic Resonance) will most probably make it possible to separate the various contributions, one of them being the external EFG created by the liquid crystal.

Chemischer Informationsdienst, Dec 25, 1973

Chemischer Informationsdienst, Nov 18, 1986

Liquid Crystals, Jul 16, 2019

NMR spectroscopy of quadrupolar noble gases, 21 Ne (spin 3/2), 83 Kr (9/2), 131 Xe (3/2), dissolv... more NMR spectroscopy of quadrupolar noble gases, 21 Ne (spin 3/2), 83 Kr (9/2), 131 Xe (3/2), dissolved in thermotropic liquid crystals enables the derivation of versatile information about the physical properties of the materials. The spectra display fine structures, triplets and nonets, which reveal quadrupole couplings. These in turn can be used in the determination of electric field gradients (EFG), orientational order parameters, and tilt angles. Comparison of 129 Xe and 131 Xe chemical shifts reveals second order quadrupole shifts (SOQS) in circumstances where the ratio of quadrupole coupling and magnetic flux density is suitable. The 131 Xe SOQS is shown to distinguish between uniaxial and biaxial nematic phases. Both 83 Kr and 131 Xe NMR spectra may display asymmetry around the central transition because of the SOQS, which can be used to identify biaxiality in nematic phases. As a curiosity, the effect of possible hexadecapole coupling on the 83 Kr NMR transitions of krypton in liquid crystals is discussed.

Elsevier eBooks, 1999

NMR spectroscopy of the two xenon nuclides 129Xe and 131Xe is described. 129Xe is a spin-1/2 nucl... more NMR spectroscopy of the two xenon nuclides 129Xe and 131Xe is described. 129Xe is a spin-1/2 nucleus with a reasonable inherent sensitivity whilst 131Xe is quadrupolar. Applications of xenon NMR spectroscopy include studies of shielding in gaseous samples, and use of xenon as a probe for liquid, liquid crystalline and solid environments. One major area of application involves studies of zeolites, and other cavity structures. The ability to obtain high spin polarizations of xenon through laser techniques has opened up the use of xenon NMR in both chemistry and biology. The NMR spectra of xenon compounds are also covered.

eMagRes, Jun 17, 2013

Information on the properties of liquid crystals (LC) can be derived by using atomic or molecular... more Information on the properties of liquid crystals (LC) can be derived by using atomic or molecular probes and measuring their NMR spectra. It has emerged that xenon-129 (due to its large polarizable electron cloud; spin ½) is very sensitive to various changes in its local environment. In LCs, this means sensitivity to temperature, density, phase transitions, phase structure, diamagnetic susceptibility, orientational and positional order parameters, and tilt angle. Information about electric field gradients in LCs may be obtained through quadrupolar xenon-131 (spin 3/2). Xenon-131 may also distinguish between uniaxial and biaxial LC phases via the second-order quadrupole shift. This article describes experiments and related theories of 129/131Xe NMR in liquid crystalline samples. Keywords: liquid crystals; xenon; phase transitions; order parameters; quadrupole coupling; second-order quadrupole shift; tilt angle

Organic magnetic resonance, Jun 1, 1975

The 300 MHz spectra of 2‐methyl‐, 2‐phenyl‐, 2‐(2‐chlorophenyl)‐ and 2‐(4‐chlorophenyl)‐oxetanes ... more The 300 MHz spectra of 2‐methyl‐, 2‐phenyl‐, 2‐(2‐chlorophenyl)‐ and 2‐(4‐chlorophenyl)‐oxetanes were recorded in CCl4 and C6D6. The chemical shifts and the proton‐proton coupling constants were solved through iterative calculations. The results were discussed in the light of structural factors and theoretical calculations. The average angle of pucker for the oxetane ring was estimated at c. 5°, in fair agreement with the value of 3·3° derived from a microwave study.

Zeitschrift für Naturforschung, Dec 1, 1974

Spin-spin coupling constants between the methine proton in the oxetane ring and the phenyl proton... more Spin-spin coupling constants between the methine proton in the oxetane ring and the phenyl protons and carbon nuclei have been calculated in different conformations in the INDO approximation for 2-phenyloxetane and 2-(4-fluorophenyl) oxetane, and in the CNDO approximation for 2-(2chlorophenyl) oxetane and 2-(3-chlorophenyl) oxetane. In each case the finite perturbation method has been used. In the case of 2-(2-chlorophenyl) oxetane a fairly high energy barrier for the rotation around the CC bond between the rings is obtained, while in the other three cases the barrier is much lower. The calculations predict an equilibrium conformation in which the oxygen atom lies almost in the plane of the aromatic ring. The calculated dipole moments of 2-(2-chlorophenyl) oxetane and 2-(3-chlorophenyl) oxetane vary significantly with conformation.

Journal of magnetic resonance, Apr 1, 1983

The deuteron quadrupole coupling constants, Q n, and methyl angles of the solute molecules CD&N, ... more The deuteron quadrupole coupling constants, Q n, and methyl angles of the solute molecules CD&N, CD,Br, CDSI, and CD3N02 were determined in various liquid-crystal solvents by use of NMR spectroscopy of oriented molecules. Carbon-13 satellifes at natural abundance in the *H or 'H spectra were used for the measurement of the degree of order of the C-D bonds. The results reveal a strong solvent dependence of Qn (maximum variation of 26% in CDjN02) as well as of the DCD angle (maximum variation of 2.3 degrees in CD& These large apparent effects are attributed to much smaller real variations occurring in a two-site interaction. A general correlation between increasing anisotropy of the solvent diamagnetic susceptibility, decreasing Qn, and increasing DCD angle is observed.

Microporous and Mesoporous Materials, Jul 1, 2001

129 Xe nuclear magnetic resonance (NMR) spectra of xenon gas adsorbed into silicoaluminophosphate... more 129 Xe nuclear magnetic resonance (NMR) spectra of xenon gas adsorbed into silicoaluminophosphate (SAPO-11) and aluminophosphate (AlPO 4-11) molecular sieve samples were recorded at variable temperatures. From the variations of the anisotropic nuclear shielding of xenon atoms adsorbed inside the sieve channels it was possible to separate the direct temperature eect and the eect due to loading variation. It was found that in the AlPO 4-11 sample, unlike in SAPO-11, several resonance signals having dierent temperature dependence arise from the non-adsorbed gas between the crystals. This behavior is shown to arise from the exchange between the external crystallite surfaces and the free intercrystallite atoms. The chemical shift variations of these signals are utilized to estimate the intercrystallite cavity sizes. Two-dimensional exchange spectra of xenon were recorded in order to reveal further the role of the intercrystallite cavities, surface physisorption and the contribution of the fast exchange of xenon to these spectral signals. Contributions of material dierences and sample composition to the nuclear shielding and the eect of sample defects on the loading level estimations are also discussed. These results are useful when analyzing the spectrum of a probe atom in a microporous material sample as a whole, not only the spectral components from the adsorbed and the free gas. Furthermore, these ®ndings help to understand the peculiar temperature dependences of the NMR spectra, even in cases with imperfect sample quality or with variations in the packing degree, particularly with high gas amounts.

Molecular Physics, Jul 1, 1978

The solvent dependence of the indirect Hg-H, Hg-C and C-H coupling constants in dimethyl mercury ... more The solvent dependence of the indirect Hg-H, Hg-C and C-H coupling constants in dimethyl mercury has been studied. The measurements show an increase of about 2 per cent in the absolute values of the Hg-H and Hg-C coupling constants on passing from neat dimethyl mercury to a solution in deuterated acetone. Solvent dependence is also observable in comparing the values

Progress in Nuclear Magnetic Resonance Spectroscopy, 1982

3.2.2. Use of nematic-isotropic phase transition. Method A 3.2.3. Gradient method. Method B 3.2.4... more 3.2.2. Use of nematic-isotropic phase transition. Method A 3.2.3. Gradient method. Method B 3.2.4. Use of smectic liquid crystals. Method C 3.25. Use of chiral mesophases. Method D 3.2.6. Sample rotation. Method E 3.2.7. Use of electric fields. Method F 3.2.8. Mixing of two thermotropic nematic liquid crystals with opposite diamagnetic anisotropies. Method G 3.3. Experimental and Theoretical Results 3.3.1. Anisotropy of proton chemical shift 3.3.2. Anisotropy of carbon-l 3 chemical shift 3.3.3. Anisotropy of nitrogen-15 chemical shift 3.3.4. Anisotropy of fluorine-19 chemical shift 3.3.5. Anisotropy of phosphorus-31 chemical shift 3.3.6. Anisotropies of the chemical shifts of other nuclei Appendix. List of Liquid Crystal Solvents used in studies of Anisotropies in Spin-Spin Couplings and Chemical Shifts Note added in proof References 1. LIQUID CRYSTAL SOLVENTS IN NMR SPECTROSCOPY

Chemischer Informationsdienst, Sep 16, 1986