• 제목, 요약, 키워드: $NaBrO_3$ crystal

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Nuclear Magnetic Resonance Study of 23Na Nucleus in NaBrO3 Single Crystal

  • Yeom, Tae Ho
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.342-346
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    • 2015
  • The nuclear magnetic resonance of the $^{23}Na$ nucleus in a $NaBrO_3$ single crystal was investigated at the temperature range of 200 K~410 K. The tendencies of temperature dependence of the nuclear quadrupole coupling for the two magnetically inequivalent Na(I) and Na(II) centers are found to be opposite to each other. The nuclear spin-lattice relaxation mechanism of $^{23}Na$ in the $NaBrO_3$ crystal is investigated, and the result revealed that the Raman process is dominant in the temperature range investigated. The relaxation process of the $^{23}Na$ nuclear spins was well described by a single exponential function in time. The $T_1$ values of the $^{23}Na$ nuclei in the $NaBrO_3$ single crystal decreased with increasing temperature. The calculated activation energy for the $^{23}Na$ is $0.032{\pm}0.002eV$.

Crystal Structures of Bromine Sorption Complexes of $Ca^{2+}$-Exchanged Zeolite A

  • 장세복;송성환;김양
    • Bulletin of the Korean Chemical Society
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    • v.16 no.12
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    • pp.1163-1167
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    • 1995
  • The structures of dehydrated Ca4Na4-A (a=12.243(1) Å) and of its bromine sorption complex (a=12.214(1) Å) have been determined by single crystal x-ray diffraction techniques in the cubic space groupPm&bar{3}m at 21(1) ℃. Both crystals were dehydrated at 360 ℃ and 2 X 10-3 Torr for 2 days and one crystal was treated with 180 Torr of bromine vapor at 24 ℃ for 1 h. The structures were refined to final error indices, R1=0.066 and R2=0.078 with 192 reflections and R1=0.109 and R2=0.093 with 100 reflections, respectively, for which I>3σ(I). In these structures, four Ca2+ and four Na+ ions are located on two different threefold axes associated with 6-ring oxygens, respectively. In Ca4Na4-A·6Br2, four Ca2+ ions are recessed 0.28(1) Å into the large cavity and four Na+ ions extend 0.63(1) Å into the sodalite unit. A total of six dibromine molecules are sorbed per unit cell. Each Br2 molecule approaches a framework oxide ion axially with O(1)-Br(1)=3.27(2) Å Br(1)-Br(2)=2.66(6) Å and O(1)-Br(1)-Br(2)=172(1)°, indicating a charge-transfer interaction.

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Synthesis and Crystal Structure of Ag4Br4 Nanoclusters in the Sodalite Cavities of Fully K+-Exchanged Zeolite A (LTA)

  • Lim, Woo-Taik;Choi, Sik-Young;Kim, Bok-Jo;Kim, Chang-Min;Lee, In-Su;Kim, Seok-Han;Heo, Nam-Ho
    • Bulletin of the Korean Chemical Society
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    • v.26 no.7
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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) $\AA$).

Formation of Mo(NAr)(PMe₃)₂Cl₃and Mo₂(PMe₃)₄Cl₄from Reduction of Mo(NAr)₂Cl₂(DME) with Mg in the Presence of PMe₃[Ar=2,6-diisopropylphenyl]

  • 정건수;박병규;Lee, Soon W.
    • Bulletin of the Korean Chemical Society
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    • v.18 no.2
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    • pp.213-217
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    • 1997
  • Magnesium reduction of Mo(N-C6H3-2,6-i-Pr2)2Cl2(DME) in the presence of trimethylphosphine led to a mixture of Mo(N-C6H3-2,6-i-Pr2)(PMe3)2Cl3, 1, and Mo2(PMe3)4Cl4, 2. In solution 1 is slowly air-oxidized to Mo(N-2,6-i-Pr2-C6H3)(OPMe3)(PMe3)Cl3, 3. 1 is chemically inert to carbon nucleophiles (ZnMe2, ZnEt2, AlMe3, AlEt3, LiCp, NaCp, TlCp, NaCp*, MeMgBr, EtMgBr), oxygen nucleophiles (LiOEt, LiO-i-Pr, LiOPh, LiOSPh), and hydrides (LiBEt3H, LiBEt3D). Crystal data for 1: orthorhombic space group P212121, a=11.312(3) Å, b=11.908(3) Å, c=19.381(6) Å, Z=4, R(wR2)=0.0463 (0.1067). Crystal data for 2: monoclinic space group Cc, a=18.384(3) Å, b=9.181(2) Å, c=19.118(3) Å, b=124.98(1)°, Z=4, R(wR2)=0.0228 (0.0568). Crystal data for 3: orthorhombic space group P212121, a=11.464(1) Å, b=14.081(2) Å, c=16.614(3) Å, Z=4, R(wR2)=0.0394 (0.0923).

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Bacillus thuringiensis의 내독소(內毒素)와 플라스미드의 분리에 관한 연구 (Studies on the Isolation of δ-Endotoxin and Plasmids in Bacillus thuringiensis)

  • 오상수;이형환
    • 한국미생물·생명공학회지
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    • v.13 no.1
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    • pp.51-57
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    • 1985
  • Bacillus thuringiensis subspecies중 HD-1, HD-9, HD-73과 finitimus의 내독소와 플라스미드분리에 대하여 얻은 실험결과는 다음과 같다. 1. 밀도구배에 의한 ${\delta}$-내독소 정제는 NaBr, CsCl, Renografin-76으로 행하여 밀도구배 재료간 독소 수율은 Renografin-76>CsCl>NaBr순으로 독소와 아포의 분리가 양호하였고 그 순도는 약 98%정도였다. 2. 정제한 내독소는 SDS-PAGE, 현미경 관찰, 생물검정으로 조사하였고, SDS-PAGE에 의한 하위단위체의 분자량은 약 66,000과 130,000달돈 이었다. 3. 내독소의 결정단백질의 외부형태는 finitimus를 제외한 3균주는 모두 이중피라마드형이었다. 4. 담배나방 유충에 대한 살충실험 결과 $0.1{\mu}g/ml$의 내독소 농도에서 HD-1은 60%, HD-73은 100% 치사율을 보였다. 5. B. thuringiensis의 플라스미드 크기는 약 0.5~120Kb 정도였고 그 수는 HD-1, HD-9, HD-73에서 각각 12, 3, 11개 였고, finitimus 균주에는 플라스미드가 없었다.

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Structural, Electrochemical, DNA Binding and Cleavage Properties of Nickel(II) Complex [Ni(H2biim)2(H2O)2]2+ of 2,2'-Biimidazole

  • Jayamani, Arumugam;Thamilarasan, Vijayan;Ganesan, Venketasan;Sengottuvelan, Nallathambi
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3695-3702
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    • 2013
  • A nickel(II) complex $[Ni(H_2biim)_2(H_2O)_2](ClO_4)_2{\cdot}H_2O$ (1) of biimidazole ligand has been synthesized and characterized (Where $H_2biim$ = 2,2'-biimidazole). The single crystal X-ray diffraction of the complex shows a dimeric structure with six coordinated psudo-octahedral geometry. The cyclic voltammograms of complex exhibited one quasireversible reduction wave ($E_{pc}=-0.61V$) and an irreversible oxidation wave ($E_{pa}=1.28V$) in DMF solution. The interaction of the complex with Calf-Thymus DNA (CT-DNA) has been investigated by absorption and fluorescence spectroscopy. The complex is an avid DNA binder with a binding constant value of $1.03{\times}10^5M^{-1}$. The results suggest that the nickel(II) complex bind to CT-DNA via intercalative mode and can quench the fluorescence intensity of EB bind to CT-DNA with $K_{app}$ value of $3.2{\times}10^5M^{-1}$. The complex also shown efficient oxidative cleavage of supercoiled pBR322 DNA in the presence of hydrogen peroxide as oxidizing agent. The DNA cleavage by complex in presence of quenchers; viz. DMSO, KI, $NaN_3$ and EDTA reveals that hydroxyl radical or singlet oxygen mechanism is involved. The complex showed invitro antimicrobial activity against four bacteria and two fungi. The antimicrobial activity was nearer to that of standard drugs and greater than that of the free ligand.