Biomedical subjects

Young-Sik Kye

Publications and source records attributed to Young-Sik Kye.

3 recordsLinked to original sources

PubMed2005

Orientation of single crystals using linear approximations to NMR transits.

We have derived analytical expressions for determining the orientation of high-symmetry single crystals from line-crossings in a single rotation plot. We demonstrate the utility of the method using the strontium-87 resonance in strontium nitrate. Employing our new method, which we call orientation of single crystals using linear approximations to NMR transits (OSCULANT), in combination with fourth-order perturbation theory, we obtain a highly accurate value for the quadrupole coupling constant, and an estimate for the chemical shielding anisotropy.

Crystallization↗

PubMed2004

Isotopomeric polymorphism.

The complex formed between 4-methylpyridine and pentachlorophenol (4MPPCP) crystallizes in a triclinic space group. If the same complex is synthesized from deuterated pentachlorophenol (4MPPCP-d1), it crystallizes in an entirely different monoclinic polymorph. Solid-state NMR of samples synthesized with a full range of deuteration levels, crystallized from solution or the melt, and in the presence or absence of seeds confirms that the isotopomers indeed have different thermodynamically stable crystal structures. The phenomenon is apparently due to very different hydrogen bond strengths between the two polymorphs.

Deuterium↗

PubMed1998

207Pb NMR of Solid Solutions of Divalent Metal Nitrates.

207Pb NMR spectra of mixed crystals of anhydrous lead and strontium nitrate show up to 13 lines, arising from lead ions with 0-12 Pb(2+) nearest-neighbor cations replaced by Sr(2+). The shifted lines are further split by the multiplicity of inequivalent nearest-neighbor replacements. The average shift per Sr(2+) ion is 21.8 ppm. Similar but somewhat smaller effects are seen in [Pb,Ba](NO(3))(2) mixed crystals. The intensities of the resonances can be fit to Monte Carlo models of Pb(2+) and Sr(2+) ion distributions and are consistent with like nearest-neighbor pairs being 120 J/mol lower in energy than unlike pairs.

Journal Article↗