• 대한화학회지
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• 제9권3호
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• pp.134-141
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• 1965

니코틴 二沃化水素酸鹽의 結晶은 直角非等軸結晶係(料方晶係)에 屬하며 空間群은 $p2_12_12_1$이다. 單位格子의 크기는 a=7.61, b=11.01 및 e=17.27${\AA}$이며 單位格子안에 들어있는 化學單位의 水는 4이다. 이 結晶의 構造를 X-線廻折法에 依하여 解析하였으며 R 値 ${\sum}{\mid}{\mid}F_{\circ}{\mid}-{\mid}F_c{\mid}{\mid}{\div}{\sum}{\mid}F_{\circ}{\mid}$ 가 $F_{orl}$와 $_{kol}$에 關하여 各各 0.16및 0.14의 값을 이룰 때까지 精密化 하였다. 原子間距離의 精密化를 試圖하지는 않았지만 피리딘 고리 안의 C-C 및 C-N의平均距離는 各各 1.40 및 $1.35{\AA}$의 값을 가진다. 피리딘 고리 內의 各原子는 實驗誤差內에서 同一平面上에 있으며 피롤리딘 고리에서는 $C_6,\;C_7,\;C_8$및$N_2$原子는 大略 同一平面上에 있으나 $C_9$는 이 平面으로 부터 約0.22${\AA}$ 떨어져있다. 피리딘 고리의 平面과 $C_6,\;C_7,\;C_8$및 $N_2$가 이루는 平面의 各法線은 約 $94^{\circ}$를 이루고 있다. 이코틴 二沃化水素酸鹽의 한 分子內의 두個의 요오드 原子中 한개는 피리딘 고리의 窒素原子와 $3.55{\AA}$의 距離로 連結되여 있으며 다른 한개는 피콜리딘 고리의 窒素原子 와 $3.58{\AA}$의 距離로 連結되여 있다. 結晶內에서 各 分子는 Van der Waals force로 서로 接燭되여 있다.

• 대한방사선기술학회지:방사선기술과학
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• 제29권3호
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• pp.147-155
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• 2006

기체 저장제로서 제올라이트의 구조와 기체분자의 유출입 기전을 이해하기 위해 완전히 탈수된 $K_3-A$들을 제조하고 $K_3Na_8H-A(R_1=0.0478,\;R_2=0.0458$ 및 $a=12.257(1){\AA}$)의 결정구조들을 Pm3m 입방 공간군에서 단결정 X-ray 회절 방법으로 연구하였다. 진공 탈수된 $K_3Na_8H-A$의 결정구조에 있어서, 단위세포 당 3개의 $K^+$ 이온들이 8-ring(0.0, 0.4531, 0.4531) 상에 존재하였고, 단위세포 당 8개의 $Na^+$ 이온들이 6-oxygen ring들의 중앙에 위치하였다. 8-ring상에 존재하는 각 $K^+$ 이온들은 두 가지 종류의 골격산소 원자들로 부터 각각 $2.87(2){\AA}$과 $2.79(1){\AA}$의 거리를 가지고 있었다. 이러한 값들은 이미 기존에 알려진 $K_{12}Na-A$의 값들보다 더 짧은 값으로 이들의 이온 반경들을 고려할 때 더 타당한 값들이였다. $K^+$ 이온들의 정확한 위치들은 8-ring들의 중앙으로부터 약 $0.8{\AA}$ 떨어져 있었다. 이러한 결과는 제올라이트 골격을 안전화시켜 기체분자들의 효과적인 유출입 통제와 저장을 가능하게 하며, 유효 부피 극대화를 이루어 더 많은 기체 저장을 할 수 있으므로 병원에서 사용하는 산소 저장 용기를 더욱더 소형임은 물론 산소가 필요한 응급환자 들을 위한 휴대하기 간편한 용기를 만들어 줄 것으로 예상된다.

• Archives of Pharmacal Research
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• 제2권2호
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• pp.99-110
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• 1979

The crystal structure of sulfapyridine, $C_{11}H_{11}N_{3}O_{2}S$, has been determined by X-ray diffraction method. The compound crystallizees in the monoclinic space group C2/c with a = 12, 80(4), b= 11.72(4), $c= 15.36(5){\AA}, {\beta}= 94(3)^{\circ}$and Z = 8. A total of 1133 observed reflections were collected by the Weissenberg method with CuKaradiation. Structure was solved by the heavy atom method and refined by isostropic block-diagonal least-squares method to the R value of 0.14. The nitrogen in the pyridine ring of sulfapyridine is associated with an extra-annular hydrogen. The C (benzene ring) S-N-C (pyridine ring) group adopts the gauche form with a fonformational angle of $71^{\circ}$. The benzene ring are inclined at angle of $84^{\circ}.to the pyridine ring plane. Sulfapyridine shows three different hydrogen bonding in the crystal. They are two N-H...O hydrogen bonds with the distance of 2.90 and 2.98${\AA}$ respectively, and on N-H...N with the distance of 3.06 ${\AA}$.

• 대한화학회지
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• 제7권4호
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• pp.257-263
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• 1963

The crystal structure of nicotinic acid hydrochloride has been determined by two-dimensional x-ray method. The unit cell is monoclinic with a = 7.21 ${\AA}$, b = 6.69 ${\AA}$, c = 7.54 ${\AA}$, ${\beta}=100^{\circ}$, space group $C{\frac{2}{2}}-P2_1$, and contains two formula units. Weissenberg diagrams have been taken along the a, b and c axes with Cu K${\alpha}$ radiation and the positions of the atoms have been fixed by means of two dimensional Patterson syntheses, a Fourier projection along the b-axis and trial and error method. The bond lengths are: pyridine ring C-C = 1.38, 1.39 ${\AA}$, C-N = 1.34, 1.36 ${\AA}$, carboxyl group $C_4-C_6$ = 1.46 ${\AA}$, $C_6-O_1$ = l.33 ${\AA}$, $C_6-O_2$ = 1.19 ${\AA}$. The ring nitrogen atom may be regarded as forming bifurcated hydrogen bond with an oxygen atom $O_2$ of one neighbouring molecule and with a neighbouring chlorine atom, being linked by forming a hydrogen bond with an other oxygen atom $O_1$ of above mentioned neighbouring molecule, in such a way that chains parallel to the c-axis are formed.

• 대한수학회논문집
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• 제37권1호
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• pp.45-56
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• 2022

In this paper, we introduce and study the class of rings in which every ideal consisting entirely of zero divisors is a d-ideal, considered as a generalization of strongly duo rings. Some results including the characterization of AA-rings are given in the first section. Further, we examine the stability of these rings in localization and study the possible transfer to direct product and trivial ring extension. In addition, we define the class of d_E-ideals which allows us to characterize von Neumann regular rings.

• 약학회지
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• 제54권4호
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• pp.300-308
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• 2010

Adrenoceptor has been considered to be an important target in psychiatric disorders. Based on x-ray structures of bovine rhodopsin, we established homology model of ${\alpha}_{2c}$-adrenoceptor (ADA2C_rat) and then analyzed docking from binding model of receptor-ligand complex with high-active compound No.29 in tricyclic isoxazole analogues (1-30). We observed that the N (1.907 $\AA$) and O (1.712 $\AA$) atoms of isoxazole ring on the docked ligand (No.29) formed H-bonding interaction with O-H of Ser5.32 and carmeron phenyl ring centroid of tricyclic isoxazole formed $\pi-\pi$ interaction at 3.342 $\AA$ distance with phenyl ring centroid of Phe6.52. According to predictions of blood-brain distribution (logBB) through penetration of blood-brain barrie (BBB) and polar surface area (PSA) of the ligands, the high-active compound No.29 has values of logBB=-0.203, PSA=67.50, respectively. These results suggest that the high-active compound No.29 is a novel anti-depressant with the characteristics such as dopamine and serotonin.

• 통합자연과학논문집
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• 제8권4호
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• pp.250-257
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• 2015

The crystal structure of the potential active 3-(4-ethylphenyl)-3H-chromeno[4,3-c]isoxazole-3a(4H)-carbonitrile ($C_{19}H_{16}N_2O_2$) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group $P2_1/c$ with unit cell dimension a=6.6869 (8) ${\AA}$, b=15.8326 (19) ${\AA}$ and c= 15.237 (2) ${\AA}$ [${\alpha}=90^{\circ}$, ${\beta}=100.663^{\circ}$ and ${\gamma}=90^{\circ}$]. In the structure chromene, isoxazole and carboxylate are almost coplanar each other. All geometrical parameters revelled that chromene ring of pyran ring adopt sofa conformation. The crystal packing is stabilized by intermolecular C-H...N and C-H...O hydrogen bond interaction.

• 통합자연과학논문집
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• 제8권3호
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• pp.184-191
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• 2015

The crystal structure of the potential active methyl-3-phenyl-3H-chromeno[4,3-c]isoxazole-3a(4H)-carboxylate ($C_{18}H_{15}NO_4$) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the orthorombic space group $P2_12_12_1$ with unit cell dimension $a=9.8320(17){\AA}$, $b=9.9890(18){\AA}$ and $c=15.588(3){\AA}$ [${\alpha}=90^{\circ}$, ${\beta}=90^{\circ}$ and ${\gamma}=90^{\circ}$]. In the structure chromene, isoxazole and carboxylate are almost coplanar each other. All geometrical parameters revelled that chromene ring of pyran ring adopt sofa conformation. The crystal packing is stabilized by intermolecular C-H...O and C-H...N hydrogen bond interaction.

• 한국결정학회지
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• 제16권1호
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• pp.1-5
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• 2005

The structure of the title compound has been determined by single-crystal X-ray diffraction work. The crystals are orthorhombic, space group $Pna2_1$ with a=11.095(3), b=21.834(7), c=12.574(4) $\AA$, and R1=0.0667. The average carbon bond length in aromaticity In the molecule is 1.386(1) $\AA$ and the average single bond length linking the central benEene ring and peripheral phenyl rings is 1.491(3) $\AA$. The average dihedral angle between the central benzene ring and each of six peripheral phenyl rings is $67.1(1)^{\circ}$ and the average dihedral angle between neighboring two phenyl rings is $55.0(1)^{\circ}$. Thus the molecule adopts a quasi-propeller configuration with approximate six-fold rotation symmetry.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1090-1096
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• 2005

$Ag_4Br_4$ nanoclusters have been synthesized in about 75% of the sodalite cavities of fully $K^+$-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar $K_4Br^{3+}$ cation. A single crystal of $Ag_{12}$-A, prepared by the dynamic ion-exchange of $Na_{12}$-A with aqueous 0.05 M $AgNO_3$ and washed with $CH_3OH$, was placed in a stream of flowing 0.05 M KBr in $CH_3OH$ for two days. The crystal structure of the product ($K_9(K_4Br)Si_{12}Al_{12}O_{48}{\cdot}0.75Ag_4Br_4$, a = 12.186(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index $R_1$ = 0.080 for the 99 reflections for which $F_o\;{\gt}\;4_{\sigma}\;(F_o)$. The thirteen $K^+$ ions per unit cell are found at three crystallographically distinct positions: eight $K^+$ ions in the large cavity fill the six-ring site, three $K^+$ ions fill the eight-rings, and two $K^+$ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring $K^+$ ions ($K_4Br^{3+}$). Three $Ag^+$ and three $Br^-$ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized $Ag_4Br_4$ clusters (interpenetrating tetrahedra; symmetry $T_d$; diameter ca. 7.9 $\AA$) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) $\AA$) is held in place by the coordination of its four $Ag^+$ ions to the zeolite framework (each $Ag^+$ cation is 2.52(3) $\AA$ from three six-ring oxygens) and by the coordination of its four $Br^-$ ions to $K^+$ ions through six-rings (Br-K = 3.00(4) $\AA$).