• Bulletin of the Korean Chemical Society
• /
• v.23 no.4
• /
• pp.555-562
• /
• 2002

Isomers based on the RS and EZ geometrical isomerism of the neutral, deprotonated species of HMPAO and their complexes with zinc(Ⅱ) ion have been investigated by semiempirical AM1 optimization method. The Hartree-Fock energies on AM1 geometries o f HMPAO species were calculated with HF/6-31G* methods. Twenty-two isomers of the neutral and twenty isomers of the deprotonated species of HMPAO have been found. The presence of four EE-series isomers of both zinc(Ⅱ) complexes with the neutral and deprotonated HMPAO have been expected and the SREE typical isomer of both types of complexes is the most stable isomer. Energies of complexation of zinc(Ⅱ)/HMPAO isomers with AM1 geometries were calculated by HF/ 6-31G*method. Due to the complexations with zinc(Ⅱ), the structural reorganizations of some isomers of the neutral HMPAO have been occurred. The optimized geometrical parameters of the related conformations have been discussed in terms of their stabilities and existences.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.8
• /
• pp.1053-1054
• /
• 2002

• Journal of the Korean Chemical Society
• /
• v.29 no.5
• /
• pp.516-521
• /
• 1985

Ethylenediamine-triacetatocobalt (III) complexes with an ammine, an ethylene-diamine, and a trimethylenediamine as the unidentate ligand were prepared, and were isolated as only one isomer for each case by the Dowex 50W-X8, cation exchange resin in $H^+$ form. The geometrical isomer of these complexes have been assigned cis-equatorial form in the three possible geometrical isomers from the elemental analysis, pH titration, IR, NMR, and electronic absorption spectrum. It was found that $[CoN_3O_3]$ system of the meridional form with multidentate ligand have the first absorption band of the largely splitting pattern, and that the diamines (ethylenediamine, trimethylenediamine) have coordinated to the central cobalt (III) ion as a unidentate ligand.

• Food Science and Biotechnology
• /
• v.17 no.1
• /
• pp.31-37
• /
• 2008

The distributions and content of geometrical isomers of conjugated linoleic acids (CLA) in dairy foods such as milk, yogurt, and cheese, produced or being sold in the Quebec province of Canada, were investigated by gas chromatographic analysis. The mean contents of total CLA (mg/g fat) were $5.06{\pm}0.74$ in 4 low-fat milk samples, $14.14{\pm}4.95$ in 6 yogurt samples, and $18.22{\pm}7.89$ in 5 natural ripened cheeses. Among the yogurt samples, YY contained the highest content of total CLA ($20.68{\pm}5.17\;mg/g$ fat). Among the cheese samples, Gruyere contained the highest amount of total CLA ($29.86{\pm}0.62$) as well as c-9,t-11 ($22.03{\pm}0.36\;mg/g$ fat), followed by Jarlsberg ($22.76{\pm}0.14$), Provolone ($16.42{\pm}0.52$), Cheddar ($13.83{\pm}0.81$), and Swiss ($8.23{\pm}1.11$). Based on the distribution ratios of CLA isomers in these dairy foods, the c-9,t-11 isomer appeared to be the major CLA isomer in both the low-fat milk ($89.87{\pm}2.39%$) and yogurt ($90.98{\pm}4.42%$). In the cheeses, however, the ratio of c-9,t-11 ($54.86{\pm}13.06%$) was slightly higher than that of c-10,c-12 ($40.81{\pm}13.40%$).

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.1
• /
• pp.60.2-60.2
• /
• 2010

We have studied the abundance ratio of HNC and HCN toward the Red MSX Sources (RMS) using HCN (J=1-0), HNC (J=1-0), $H^{13}CN$ (J=1-0), $HN^{13}C$ (J=1-0),and $N_2H^+$ (J=1-0) lines observed with the Mopra 22 m radio telescope. The RMS are massive young stellar objects identified by the MSX satellite data combined with the 2MASS data. HCN and HNC (a geometrical isomer of HCN) are among the most basic interstellar molecules. According to our analysis, the column density of HCN is found to be correlated with that of HNC. Additionally, the [HNC]/[HCN] abundance ratio is sensitive to the core temperature because HNC is depleted in high temperature regions. This result is consistent with the previous results seen in low mass starless or protostellar cores.

• Journal of the Korean Chemical Society
• /
• v.22 no.3
• /
• pp.133-137
• /
• 1978

A straight chain flexible tetraamine ligand, 1,l0-dipropyl-5R-methyltriethylenetetraamine(R-$Pr_2$metrien) has been synthesized, and the dichloro and dinitro cobalt(III) complexes of this ligand have been prepared. The ligand has been expected to show a topological preference for the trans isomer. As expected, only trans geometrical isomers have been obtained and their structures have been elucidated via elemental analyses, nmr, electronic absorption and CD data.

• Archives of Pharmacal Research
• /
• v.26 no.2
• /
• pp.138-142
• /
• 2003

From the pulp of Euphoria longana (Longan Arillus), three cerebroside molecular species have been isolated. Six known cerebrosides, soyacerebrosides I and II, 1-Ο-$\beta$-D-glucopyranosyl-(2S,3R,4E,8E)-2-(2 -lignoceroylamino)-4,8-octadecadiene-1,3-diol (long an cerebroside I) and its 8Z isomer (Iongan cerebroside II), momor-cerebroside I, and phytolacca cerebroside, were identified as major components of these cerebroside molecular species. All the cerebrosides were shown to be a mixture of geometrical isomers (8E and 8Z) of sphingosine-type or phytosphingosine-type glucocerebrosides possessing 2-hydroxy fatty acids. The structures of these cerebrosides have been determined on the basis of chemical and spectroscopic evidence.

• Applied Biological Chemistry
• /
• v.35 no.5
• /
• pp.395-398
• /
• 1992

In order to study the influence of a 6'-methyl group in ring C of griseofulvin ${\underline{(1)}}$ on the fungicidal activity, 6'-methyl group was replaced with a larger phenyl group as $({\pm})-6'-phenylgriseofulvin$ ${\underline{(3)}}$, $({\pm})-6'-epiphenylgriseofulvin$ ${\underline{(4)}}$, synthesized by a Diels-Alder cycloaddition. Their biological activities were examined against Botrytis allii (IFO 9430) and B. cinerea (AHU 9573). $({\pm})-6'-Phenylgriseofulvin $ ${\underline{(3)}}$ showed high activity in $25\;{\mu}g/disc$.

• Korean journal of food and cookery science
• /
• v.7 no.1
• /
• pp.45-51
• /
• 1991

In this study, several standard fatty acids were analyzed by three analysis instruments. And also, for the two kinds of soybean oils, fatty acids compositions were determined by three instruments. The results were obtained as follows: 1. In the case of Gas Chromatography (GC), standard fatty acids (Myristic, Stearic, Linoleic, Linolenic, Arachidonic acid) were determined with high reproducibility, but oleic acid/elaidic acid were not seperated. By Capillary Gas Chromatography (CGC), most of standard fatty acids were determined with very high reproducibility than saturated fatty acids, and palmitic acid/oleic acid were not seperated. 2. In the analytical ability of cis-trans fatty acids isomer (oleic acid/elaidic acid), CGC was shown better analytical ability of geometrical isomer than HPLC. Oleic acid/elaidic acid were not seperated by packed column (15% DEGS). The rquire time for standard fatty acids analysis was as follows; GC, 7.21 min., CGC, 9.84 min., HPLC, 24.48 min. 3. The major compositions of fatty acids of each soybean oil (CSOY; refined, DSOY; unrefined) by GC and CGC were linoleic acid, oleic acid, palmitic acid, linolenic acid and stearic acid. But in the case of HPLC, palmitic acid/oleic acid were not seperated. Analytical ability of three instruments on fatty acids composition in each soybean oil was same trend as in the standard fatty acids mixture.

• Journal of the Korean Magnetics Society
• /
• v.17 no.1
• /
• pp.47-50
• /
• 2007

[ $ZnCr_2O_4$ ] shows geometrically frustrated magnet. Recently, $CoCr_2O_4$ has been investigated for multiferroic property and dielectric anomalies by spin-current model. Polycrystalline $CoCr_2O_4$ and $CoCrFeO_4$ compounds was prepared by wet-chemical process. Crystallographic and magnetic properties of $CoCr_2O_4$ and $CoCrFeO_4$ were investigate by using the x-ray diffractometer(XRD), vibrating sample magnetometer(VSM), superconducting quantum interference device magnetometer(SQUID), and $M\"{o}ssbauer$ spectroscopy. The crystal structure was found to be single-phase cubic spinel with space group of Fd3m. The lattice constants of $CoCr_2O_4$ and $CoCrFeO_4$ $a_0$ were determined to be 8.340 and 8.377 ${\AA}$, respectively. The ferrimagnetic transition temperature for the both samples were observed at 97 K and 320 K. The $M\"{o}ssbauer$ absorption spectra at 4.2 K show that the well developed two sextets are superposed with small difference of hyperfine field($H_{hf1}=507\;and\;H_{hf2}=492\;kOe$). Isomer shift values($\delta$) of the two sextets are found to be 0.33 and 0.34 mm/s relative to the Fe metal, respectively, which are consistent with the high spin $Fe^{3+}$ charge state.