• 한국세라믹학회지
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• 제40권6호
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• pp.513-518
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• 2003

La/sub 2/3-x/Li/sub 3x/□/sub 1/3-2x/TiO₃ compounds with x=0.13 and 0.12 were prepared by slow cooling (x=0.13) and rapid quenching (x=0.12) into the liquid nitrogen after sintering at 1350℃ for 6 h. Their crystal structure has been determined by Rietveld refinement of both the powder neutron and X-ray diffraction data. From neutron diffraction data, we found that the main phase was not tetragonal (P4/mmm), but trigonal (R3cH). The refinement of neutron diffraction for the slow cooled samples were in a good agreement with a new model; a mixture of trigonal (R3cH, 45.7 wt％), tetragonal (p4/mmm, 37.0 wt％), and Li/sub 0.57/Ti/sub 0.86/O₂(pbnm, 17.2 wt%), but the quenched sample was found not to contain tetragonal (p4/mmm). X-ray diffraction data couldn't be well fitted because of the Poor scattering factor of lithium ions and the similar reflection patterns among trigonal (R3cH), tetragonal (p4/mmm), and cubic (Pm3m). We also knew that one transport bottlenecks is destroyed by one La vacancy in the case of trigonal (R3cH).

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.491-498
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• 1992

Chelating triphosphines were applied to freeze the fluxionality and to minimize the number of isomers found in the monophosphine analogues and this technique was proved to be useful. RuH(NO)$P_3$($P_3$; Cyttp, ttp and etp) complexes were characterized to have similar trigonal bipyramidal structures with linear NO groups. Cyttp prefers to have a meridional geometry while etp prefers a facial one and ttp complexes are mixture of these two isomers. The crystal structure of RuH(NO)(Cyttp) has been determined to have a distorted trigonal bipyramidal structure with a linear NO in the equatorial plane. The crystals are orthorhombic, space group $P_{nma}$, with unit cell dimensions a = 16.356(2), b = 20.474(2), c = 10.915(l) ${\AA}$, V = 3655 ${\AA}^3$, Z = 4, R = 0.035 and $R_w$ = 0.034 for the 2900 intensities with $F_o^2 >3{\sigma}(F_o^2)$ and the 208 variables.

• Applied Biological Chemistry
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• 제37권2호
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• pp.124-129
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• 1994

25%(v/v) dioxane 수용액의 넓은 pH범위에서 살충성 $O,O-Diethyl-{\alpha}-cyanobenzylideneamino-oxyphosphorothioate(Volaton^{\circledR})$의 가수분해 반응은 용매효과 (pH 6.0; m=0.21, n=1.55, pH 12.0; m=0.42, n=3.14 및 $|m|{\ll}|l|$), 반응 속도식, 일반염기 촉매효과, 가수분해 반응생성물 분석 및 분자 궤도(MO) 함수 계산 등의 결과로부터 trigonal bipyramidal$(sp^3d^2)$중간체를 경유하여 pH 7.0 이하에서는 $A_{AC}2$형 반응, 그리고 pH 9.0 이상에서는 $B_{AC}2$형 반응이 일어난다. Volaton의 가수분해 반응성은 입체 장애보다는 양하전 크기$(p{\gg}{\alpha}C_2)$에 의존적이며 $pH\;7.0{\sim}9.0$ 사이에서는 이들 두 반응이 경쟁적으로 일어나는 반응 메카니즘을 제안하였다.

• 한국결정학회지
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• 제15권1호
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• pp.9-17
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• 2004

Trigonal system에 屬한 25個 space group들 中 18個는 hexagonal axes만을 나타내는 lattice letter p로 表示되고, 나머지 7個의 rhombohedral space groups R3(146), $R\={3}$(148), R32(155), R3m(160), R3c(161), $R\={3}m$(166), $R\={3}c$(167)은 첫째 3개의 lattice points (0, 0, 0), (2/3, 1/3, 1/3), (1/3, 2/3, 2/3)를 갖는 hexagonal cell in obverse setting과 둘째 primitive rhombohedral cell의 두 가지로 表示된다. 本 論文에서는 space group $R\={3}c$(167)에 대하여 論한 後 이 space group에 屬한 化合物인 tris(1,2,3,4-tetraphenylbuta-1,3-dienyl)cyclotriphosphazene, $C_{84}H_{60}N_3P_3$의 構造를 hexagonal 및 rhombohedral cell 의 양쪽으로 糾明하여 發表하였다.

• 대한화학회지
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• 제56권4호
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• pp.440-447
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• 2012

Heteroleptic complexes of zirconium (IV) derived from bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic ${\beta}$-diketones of the general formula ZrLL' (where $LH_2=RCNH(C_6H_4)SC:C(OH)N(C_6H_5)N:CCH_3$, $R=-C_6H_5$, $-C_6H_4Cl(p)$ and $L^{\prime}H_2=R^{\prime}C:(NOH)C:C(OH)N(C_6H_5)N:CCH_3$, $R^{\prime}=-CH_2CH_3$, $-C_6H_5$, $-C_6H_4Cl(p)$ were prepared by the reactions of zirconium tetrachloride with disodium salts of Schiff bases ($L\;Na_2$) and oximes of heterocyclic ${\beta}$-diketones ($L^{\prime}\;Na_2$) in 1:1:1 molar ratio in dry refluxing THF. The structures of these monomeric zirconium (IV) complexes were elucidated with the help of elemental analysis, molecular weight measurements, spectroscopic (IR, NMR and mass) studies. A distorted trigonal bipyramidal geometry may be suggested for these heteroleptic zirconium (IV) complexes. The ligands (bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic ${\beta}$-diketones) and their heteroleptic complexes of zirconium (IV) were screened against A. flavus, P. aeruginesa and E. coli.

• 한국결정학회지
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• 제3권1호
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• pp.31-36
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• 1992

플루오로시노론 아세토나이드, C24H30F2O6, 삼사 정계, 공간군 R3(육방정계 단위세포), a=b=17. 896 A., c: 18365 ,3,, V=5094.3 A',2:9 A(MoK a) =0.7107 k, D-: 1.31 g/cm", D.: 1.328 g/cm", T=298 K,1101 개의 독립된 회절반점에 대한 최종신뢰도값 R=0.050. 분자구조는 관련된 코티코 스테로이드 화합물의 구조와 일치한다. 3회 회전 대칭 관계에 있는 세개의 분자가 수소결합에 의해 서로 연결되어, c-축에수직한 층을 형성한다.

• Bulletin of the Korean Chemical Society
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• 제8권1호
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• pp.1-3
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• 1987

The crystal structure of $K_5Na_2[SbW_6O_{24}]{\cdot}12H_2O$ has been determined. Final R = 0.081 for 890 observed independent reflections collected by diffractometry. Crystal data as follows; trigonal, space group R3m, a = 9.794(1) ${\AA},\;{\alpha}$ = 84.72$(1)^{\circ}$, Z = 1. The heteropolyanion has a structure with point symmetry $D_{3d}$ (3m), of the ideal Anderson-type heteropolyanion. The Sb-W and W-W distances are 3.259(2) and 3.259(3) ${\AA}$. Three types of W-O ($W-O_t,\;W-O_b\;and\;W-O_c$) distances are 1.73(2), 1.95(4) and 2.20(3) ${\AA}$. The Sb-O distance is 1.97(3) ${\AA}$.

• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.498-503
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• 1992

The protonation of RuH(NO)(Cyttp) resulted in the formation of $[RuH_2(NO)(Cyttp)]^+$ which is characterized as a classical cis-dihydried complex. This complex is fluxional and the intramolecular process involving a molecular hydrogen complex is proposed. This mechanism was further supported by the reactivity of this complex toward neutral 2-electron ligands. On the other hand, it failed to detect the existence of $[RuH_2(NO)(etp)]^+$ probably due to instability of the complex but the crystal structure of $[Ru(PMe_3)(NO)(etp)]^+$ formed by the protonation of RuH(NO)(etp) followed by the addition of $PMe_3$ was determined to have a trigonal bipyramidal structure with a linear NO in the equatorial plane and a facial etp ligand. The crystals are monoclinic, space group P21/n, with unit cell dimensions a = 14.130(2), b = 21.026 (3), c = 14.760 (1) ${\AA}$, ${\beta}$ = 97.88 $(l)^{\circ}$ V = 4344 ${\AA}^3$, Z = 4, R = 0.046 and $R_w$ = 0.056 for the 4779 intensities with $F_o^2 > 3{\sigma}(F_0^2)$ and the 440 variables.

• Bulletin of the Korean Chemical Society
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• 제27권7호
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• pp.1038-1042
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• 2006

A new type of DTPA-bis-amides (L1-L4) and their Gd(III)-complexes of the type $[Gd(L)(H_2O)]{\cdot}nH_2O$ (5: L1; 6: L2; 7: L3; 8: L4) have been prepared and characterized by analytical and spectroscopic techniques. The X-ray crystal structure of 8 has been determined for structural confirmation. The coordination geometry adopts a tricapped trigonal prism geometry with L4 acting as a chelate octadentate and a water molecule in the coordination sphere. Crystals are monoclinic, $P2_1$, a = 14.468(3), b = 19.235(4), c = 13.527(2) $\AA$ $\beta$ = $107.245(3)^{\circ}$, V = 3595.2(11) $\AA^3$, Z = 4, $D_{calc}$ = 1.570. Significant increases in relaxivities are observed with 6 and 7 as compared with that of $Omniscan^{(R)}$, a commercial MR agent: R1 = 12.46 $mM^{-1}\;s^{-1}$, R2 = 8.76 $mM^{-1}\;s^{-1}$ for 6; R1 = 12.77 nm-1 s-1, R2 = 7.60 mM-1 s-1 for 7; R1 = 4.9 $mM^{-1}\;s^{-1}$, R2 = 4.8 $mm^{-1}\;s^{-1}$ for $Omniscan^{(R)}$. In the case of 5, however, both R1 and R2 are found to be lower to show 2.09 $mM^{-1}\;s^{-1}$, and 1.82 $mM^{-1}\;s^{-1}$, respectively.

• Bulletin of the Korean Chemical Society
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• 제15권3호
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• pp.245-249
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• 1994

NaMg[$Cr(C_2O_4)_3]{\cdot}10H_2O$ crystallizes in the trigonal space group P$\bar{3}$c1, with a=b= 16.969(3), c=12.521(3) ${\AA}$, ${\alpha}={\beta}=90^{\circ},\;{\gamma}=120^{\circ},\;{\rho}=1.734 \;gcm^{-3},\;{\mu}=6.46\;cm^{-1}$, Z=6. Intensities for 1062 unique reflections were measured on a four-circle diffractometer with Mo K${\alpha}$ radiation (${\lambda}=0.71069\;{\AA}$). The structure was solved by direct methods and refined to a final ${\omega}$R value of 0.084. X-ray crystal structure showed that magnesium ion appears to be occupied over two sites with the occupancy ratio of 2:1. The crystal possesses 10 water molecules instead of previously estimated 9 water molecules.