• Bulletin of the Korean Chemical Society
• /
• 제12권2호
• /
• pp.193-196
• /
• 1991

The $^{13}C-NMR$ shifts of a series of para-substituted $8-aryl-tricyclo[3.2.1.0^{2,7}]oct-8-yl$ and $9-aryl-tricyclo[3.3.1.0^{2,8}]-non-9-yl$ cations were measured in $FSO_3H/SO_2ClF\ at\-90^{\circ}$ in order to examine whether the ${\rho}^{C^+}$ values can be used as a measure of the geometric influence on the charge delocalization resulting from ${\rho}$ conjugation in rigid tricyclopropylcarbinyl cations. Plot of the ${\Delta}{\delta}^{C+} shifts against the ${\sigma}^{C+}$ constants revealed excellent linear correlation. The 8-aryl tricyclooctyl systems yielded a ${\rho}^{C+}$ value of -5.00 with r = 0.9962. Previous investigation of the 9-aryl-tricyclononyl systems gave a correlation coefficient of r = 0.9948 with a slope of ${\rho}^{C+}$ = -4.95. A fair parallelism exists between the results of $^{19}F-NMR $ studies and the change of ${\rho}^{C+}$ value in these cations. Consequently, it is established that the ${\rho}^{C+}$ value can be used to explain the mechanism of charge stabilization of the rigid cyclopropylcarbinyl cation such as tricyclo $[3.2.1.0^{2,7}]oct-8-yl$ cation.

• 한국동물학회지
• /
• 제23권3호
• /
• pp.137-148
• /
• 1980

토끼 골격근 小胞體의 ATPase 活性에 미치는 $Hg^{2+}, Cu^{2+}, Pb^{2+}, Cd^{2+}, Mn^{2+}$ 등 2價 陽이온을 영향을 비교 측정하였다. 이들 陽이온은 $Mn^{2+}$을 제외하고 모두 이 酵素의 活性을 阻害하였다. $Mn^{2+}$은 低濃度 (12.5-100 $\mu$M)에서는 오히여 活性을 증가시켰고, 그 보다 高濃度에서는 극히 약하게 阻害하였다. $Mn^{2+}$을 제외한 위의 2價 陽이온들의 阻害龍은 $Hg^2$가 가장 컸고 (阻害係數 Ki = 10$\mu$M), rm 다음이 $Cu^{2+}$ (Ki = 30$\mu$M), $Pb^{2+}$ (Ki = 120$\mu$M), $Cd^{2+}$ (Ki = 320$\mu$M)의 순이었다. 위의 4종의 陽이온들의 ATPase에 대한 阻害作用을 可逆的 非競爭的 阻害로 판정되었다.

• 대한화학회지
• /
• 제31권1호
• /
• pp.14-24
• /
• 1987

실리카 및 제올라이트의 OH기 또는 교환된 양이온과 CO분자간의 상호작용과 전자구조를 살펴보기 위하여 CNDO/2계산을 행하였다. 실리카의 OH기와 CO분자간의 상호작용에너지는 약 12kcal/mol이었고, 그 결합거리, R(O-H${\cdots}$C)는 2.6${\AA}$이었다. 여러가지의 양이온과 CO분자와의 결합강도는 $H^+ < Na^+ < Li^+$의 순이었는데, 그것은 양이온의 정전기적 장의 세기와 일치하였다. 또한 OH기나 양이온과 결합하고 있는 CO분자의 결합차수는 OH-CO type의 경우를 제외하고는 모두 증가하였다. 제올라이트에 있는 양이온을 떼어내는데 필요한 에너지는 $H^+ > Li^+ > Na^+$의 순이었으며, 이것은 제올라이트의 골격으로부터 양이온으로 이동되는 전하의 양과 관계가 있다.

• 대한화학회지
• /
• 제41권2호
• /
• pp.77-81
• /
• 1997

거대고리 리간드인 1,12-diaza-3,4;9,10-dibenzo-5,8-dioxacyclopentadecane$(NtnOenH_4)$와 1,12,15-triaza-3,4;9,10-dibenzo-5,8-dioxacyclo-heptadecane$(NdienOenH_4)$를 운반체로 포함한 클로로포름 액체막을 통한 운반속도는 Ni(II)$({\Delta}Gp)$값을 구하여 본 결과, 운반속도의 순위는 전이금속 양이온들이 갖는 분배수화 자유에너지의 음의 값의 크기에 비례함을 알 수 있었다.

• 대한방사성의약품학회지
• /
• 제8권2호
• /
• pp.63-70
• /
• 2022

The development of myocardial perfusion imaging (MPI) agents has been motivated because coronary artery disease has been one of the leading causes of death worldwide since the 1960s. Several positron emission tomography (PET) MPI agents were developed, and ¹⁸F-labeled phosphonium cations were reported actively among them. In this study, we synthesized novel ¹⁸F-labeled phosphonium cations, (5-[¹⁸F]fluoropentyl)diphenyl(pyridin-2-yl)phosphonium and (2-(2-[¹⁸F]fluoroethoxy)ethyl)diphenyl(pyridin-2-yl)phosphonium, and evaluated potential as MPI agents. Two labeled compounds were synthesized via nucleophilic substitution reactions of ¹⁸F-fluoride with the appropriate tosylate precursor in the presence of Kryptofix 2.2.2 and K₂CO₃. MicroPET studies were performed in normal rats to evaluate in vivo distribution of radiolabeled phosphonium cations for 60 min. The radiolabeled compounds were synthesized with 5%-10% yield. The radiochemical purity of labeled compounds was > 98% by analytical HPLC, and the specific activity was > 11.8 GBq/µmol. The result of microPET studies of these labeled compounds in rats showed intense uptake in the myocardium at 30 and 60 min. The results suggest that these ¹⁸F-labeled novel phosphonium cations would have potential as promising candidates for myocardial perfusion imaging.

• 한국토양비료학회지
• /
• 제14권1호
• /
• pp.37-43
• /
• 1981

초지개발(草地開發)이 유망시(有望視)되는 전국각지(全國各地)의 미개간(未開墾) 산지토양(山地土壤)의 표토(表土)를 채취(採取)하여 Hom$\grave{e}$s의 Systematic Variation 방법(方法)에 의(依)한 다량요소(多量要素) Cations K: Ca: Mg 적정시비비율(適正施肥比率) 결정(決定)을 위(爲)한 Pot 시험(試驗)을 수원(水原)에서 수행(遂行)한 결과(結果)는: 1. 안양등(安養等) 6개지역(個地域)의 토양(土壤)에 대(對)한 혼파재배(混播栽培) 시(時) 각(各) 토양(土壤) 및 초종별(草種別) 다수확(多收穫)을 위(爲)한 당량비 기준(基準) Cations K: Ca: Mg 적정시비비율(適正施肥比率)이 계산(計算)되었다. (표(表)4). 2. 혼파목초중(混播牧草中) 두과수량증수(荳科收量增收)를 위(爲)해서는 대구(大邱), 대관령토양(大關嶺土壤)에서는 K, 광주(光州), 운봉(雲峰)은 Ca, 제주(濟州)는 Mg 적정시비비율(適正施肥比率)이 높았고 이는 토양중(土壤中) 이들 이온들의 함량(含量) 또는 함량비율(含量比率)이 낮은 것과 병관되었다. 3. 두과목초수량(荳科牧草收量)은 화본과수량(禾本科收量)보다 Cations 시비비율(施肥比率) 및 시비량(施肥量)에 크게 영향(影響)을 받고 이에따라 혼파목초(混播牧草)의 총수량(總收量), 품질(品質), 식생비율(植生比率)이 또한 영향(影響)을 받는다. 4. 화본과(禾本科) 및 두과목초(荳科牧草)의 K, Ca, Mg 함량(含量)에 미치는 이들 ion간(間)의 길항효과(拮抗效果)의 차(差)와 그리고 이들 ion들이 Na, Fe, Mn, Cu, Zn 함량(含量)에 미치는 영향(影響)에 관(關)해 논하였다. 5. 화본과목초(禾本科牧草)에서 K-group 처리(處理)에서만 K/(Ca+Mg) 당량비가 grass tetany 한계치(限界値)인 2.2보다 훨씬 높은 2.4~3.3에 달(達)했고 반면(反面)에 두과목초(荳科牧草)는 0.9~1.2로 미달(未達)되었다. 이는 적당한 화본과(禾本科) 두과(荳科) 식생비율유지(植生比率維持)는 grass tetany 유발(誘發)을 크게 줄일 수 있음을 나타낸다.

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1561-1565
• /
• 2012

The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the $NH_2$ group upon ionization. Ionization favors the intramolecular proton transfer process, leading to a proton-transferred radical-cation structure, [$NH_3{^+}-CHCH_3-COO{\bullet}$], which contrasts with the fact that a proton-transferred zwitterionic conformer is not stable for a neutral alanine in the gas phase. The energy barrier during the proton transfer process is calculated to be about 6 kcal/mol.

• 한국응용과학기술학회지
• /
• 제22권1호
• /
• pp.9-14
• /
• 2005

Competitive solvent extraction of alkaline earth metal cations from water into organic solvent containing the carboxylic acid crown ether and analogous crown ether phosphonic acid monoethyl esters were investigated. sym-(n-Decyldibenzo)-16-crown-5xyacetic acid $\underline{1}$ and monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{3}$ are structurally identical except for the ionizable groups. Both of them provide similar extraction behavior in terms of efficiency and selectivity, but monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{3}$ showed higher alkaline earth metals loadings at acidic or neutral media. Monoethylsym-(n-octyldibenzo)-16-rown-5-oxymethylphosphonic acid $\underline{2}$ showed better selectivity and alkaline earth metals loading than did the analogous sym-(n-octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid $\underline{6}$.

• 한국자기학회지
• /
• 제15권2호
• /
• pp.85-91
• /
• 2005

Effect of different cations to the formation of iron oxyhydroxide was studied using $M\ddot{o}ssbauer$ spectroscopy, X-ray diffraction (XRD) and BET. Redox Potential and pH were measured for the determination of the internal reaction rate, as well. The phases of iron oxyhydroxide could not be the same with each other, due to the presence of different cations in solution. Although the oxyhydroxide compound was composed of the same phases, the fraction of each phase was different from each other. The internal reaction rate was varied by the substitution of cation. It could be a cause of the different phase and particle size of oxyhydroxide compound.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2000년도 학술발표회 발표논문집
• /
• pp.531-535
• /
• 2000

This study was carried out to investigate water quality of streamflow in a forest land. We measured discharges and the concentration of streamflow for T-N, T-P, COD, cations(Na$\^$+/, K$\^$+/, Ca$\^$2+/, Mg$\^$2+/), and anions(CI$\^$－/, SO$\_$4/$\^$2-/). The average concentration of pollutants were extremely low, such as 0.4mg/$\ell$ for T-N, 0.02 mg/$\ell$ for T-P and 2.68mg/$\ell$for COD. The concentration of cations have a tendency to decrease with increasing discharge, while the concentration of SO$\_$4/$\^$2-/) increase with increasing discharge. It was found that the average concentration of Ca$\^$2+/ was highest and that of K$\^$+/ was lowest among cations.