• 한국결정학회지
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• 제11권2호
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• pp.71-74
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• 2000

The title compound, [Cr(OC3H6N2)6](NO3)3·4H2O, was crystallized in the centrosymmetric space group P with two half molecules in an asymmetric unit, and the two complete molecules are generated by inversion symmetry located at Cr atoms. Therefore, the Cr atoms are coordinated to six imidazolidone ligands through the oxygen atoms, and both CrO6 units have a slightly distorted octahedral geometry.

• 한국결정학회지
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• 제11권3호
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• pp.147-150
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• 2000

The complex [CuL}Cl₂·3H₂O(1)(L=2,13-bis(2-hydroxyethyl)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0/sup 1.18/,0/sup 7.12/] docosane) has been synthesized and characterized by X-ray crystallography. 1. crystallized in the monoclinic, space group C2/c, with a=21.647(6)Å, b=8.549(1)Å, c=18.132(5)Å, β=118.58(2)°, V=2946.8(12)ų, Z=4, R₁(wR₂) for 2374observed reflections of [I>2σ(I)] was 0.052(0.187). The centrosymmetric complex 1 has an axially elongated octahedral geometry with four secondary and tertially amines of the macrocycle and tow oxygen atoms of the pendant hydroxyethyl groups.

• 한국결정학회지
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• 제10권2호
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• pp.114-118
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• 1999

The title compound consisting of a calix[4]arene molecule with four phenyl rings arranged alter-nately in anti-orientation fashion, two propyloxy groups, and four para-tert-butyl group, attached on the upper rim of calix[4]arene, and polyether chain with two phenyl rings attached on the lower rim of calix[4]arene offers a big cavity inside the molecule that might possess a potential for form-ing host-guest complexes.

• 한국결정학회지
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• 제14권1호
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• pp.13-15
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• 2003

For all primitive centric space groups in the triclinic, monoclinic and orthorhombic systems, either phase 0 or π can be allocated to three different kinds of reflections in order to specify the origin at one of the eight centers of symmetry. and the same holds for all primitive acentric space groups belonging to the point group 222. If these phased reflections are used as a basic set, more and more phased reflections with better accuracy could emerge in the process of direct methods.

• 한국결정학회지
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• 제14권1호
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• pp.32-34
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• 2003

여러 조건하에서 Clonorchis sinensis로부터 helminth glutatione S-transferase(28kDa isozyme)가 결정화되었다. 0.05 M potassium 완충 용액 (pH 7.0) 내에서 10% polyehtylene glycol MME 550(PEG MME 5 K)에서 자라난 결정이 $3.0{\AA}$ 분해능까지 회절하였다. 이 결정의 결정학적 자료는 다음과 같다 : 단사정계 공간 군 C2, $a=95.83{\AA}$, $b=63.82{\AA}$, $c=235.09{\AA}$, ${\beta}=97.2^{\circ}$.

• Journal of Magnetics
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• 제12권3호
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• pp.108-112
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• 2007

Nature of phase transition in $LaVO_3$ has been studied using X-ray diffraction, SQUID magnetometer, and $M\"{o}ssbauer$ spectroscopy with 1% of $^{57}Fe$ doped sample. The crystal structure was orthorhombic with space group Pnma. Antiferromagnetic phase transition temperature $T_N$ was 140K, below which a weak ferromagnetic trace has been found. $M\"{o}ssbauer$ spectra below $T_N$ were single set of hyperfine sextet, which enabled us to discard the possibility of two inequivalent magnetic sites or uncompensated antiferromagnetism. Hyperfine magnetic field abruptly disappeared as low as about 90K, much below $T_N$.

• Bulletin of the Korean Chemical Society
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• 제12권5호
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• pp.525-529
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• 1991

A simple route is described for the selective functionalization of calixarene at the para positions of phenyl rings. Calix[4]arene tetraacetate 2, obtained from the treatment of calix[4]arene with acetic anhydride, undergoes Fries rearrangement to yield the diametrically para substituted p-diacetylcalix[4]arene 3 in 80% yield. The crystal and molecular strucutre has been determined by X-ray diffraction method. The crystals are orthorhombic, space group Pna21, with a = 11.121 (3), b = 10.374 (3), c = 21.690 (6) $\AA$ and Z = 4. The structure was solved by direct method and refined by full-matrix least-squares methods to final R of 0.036 for 1795 observed reflections. Each hydroxyl hydrogen atom is disordered over two positions. The macrocycle exists in the cone conformation which is determined by the strong circular intramolecular flip-flop type hydrogen bonds of phenolic OH, while crystal packing effects of the diametrically para-acetyl substituents seem to be responsible for the distortion of the cone conformation.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1295-1298
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• 1999

Novel platinum(IV) complexes with asymmetric chiral diamine ligands cis,cis,trans-A2PtCl2(X)2 (X = OH, OCOCH3, OCOC2H5, A2 =NH2CH(CH3)CH2NH(c-C6H11)(apcha), NH2CH(CH3)CH2NH(c-C5H9)(apcpa)) have been prepared. One of the platinum(IV) complexes, (apcpa)PtCl2(OCOC2H5)2(6), was subjected to X-ray crystallographic analysis. The crystal structure of (apcpa)PtCl2(OCOC2H5)2 (monoclinic, P21 (No. 4), a = 9.1391(1), b = 22.2517(1), c = 10.0687(1)Å, β= 109.105(1)。 , V = 1934.80(3)Å3 , Z = 4, R1 = 0.0532) exhibits that the platinum atom achieves a typical octahedral arrangement with two nitrogen atoms in cis positions and two carboxylato group in trans positions. The spectroscopic data disclose that these platinum(IV) complexes are stable and their molecular structures are retained in aqueous solution. The title complexes are highly cytotoxic in vitro but do not exhibit oral anticancer activity in vivo.

• Biodesign
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• 제7권1호
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• pp.24-27
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• 2019

Pnc1 converts nicotinamide to nicotinic acid to generate NAD⁺ through the Preiss-Handler pathway that is one of the NAD⁺-salvage pathway. By reducing levels of nicotinamide, an inhibitor of the NAD⁺-dependent histone deacetylase Sir2, yeast Pnc1 contributes gene silencing. In this study, to understand the structural features and molecular mechanism of nicotinamidase Pnc1, we overexpressed, purified, and crystallized the N-terminally His₆-tagged Pnc1 protein from Kluyveromyces lactis and obtained X-ray diffraction data at a resolution of 2.2 Å. The crystals of the K. lactis Pnc1 (KlPnc1) belonged to space group P2₁2₁2₁ with unit cell parameters a=38.5, b=77.3, c=83.3, and α=β=γ= 90°. There is one molecule in the asymmetric unit.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.5-8
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• 1995

The crystal structure and dielectric propoerties of $(Pb_{1-x}Ca_x)(Zr_{1-y}Sn_y)O_3$ Ceramics were investigated. Sn substitution reduced the volitility of PbO due to the decrease of the unit cell. The crystal structure of $(Pb_{1-x}Ca_x)(Zr_{1-y}Sn_y)O_3$ Ceramics was refined based on Orthorhombic Cmmm space group, More than two types of phase transition were observed, These phase transitons make the posicitve and negative temperature coefficient of dielectric constant of $(Pb_{1-x}Ca_x)(Zr_{1-y}Sn_y)O_3$.