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11.
12.
A new kinetic-catalytic method by the initial rate procedure for the determination of nanogram level of iron(III) is developed, which is based on its catalytic effect on the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with N,N-dimethylaniline (DMA) to form an indamine dye (λmax=590 nm) in the presence of hydrogen peroxide. Iron(II) is also determined, being oxidized to iron(III) by hydrogen peroxide. Calibration graphs obtained by the initial rate method are linear in the range 1–1000 ng ml−1 Fe and as low as 10−8 M Fe(II, III) can easily be determined. The relative standard deviations are 6.6, 2.5 and 1.5% for ten determinations of 1, 20 and 60 ng ml−1 of Fe(III), respectively. The method is applicable to the determination of iron in natural waters without preconcentration and separation. 相似文献
13.
邻羧基苯甲醛苯甲酰腙稀土配合物的合成和抗氧化活性 总被引:6,自引:0,他引:6
通过邻羧基苯甲醛与苯甲酰肼在苯中的缩合反应制备了邻羧基苯甲醛苯甲酰腙 (H2 L)。在水中合成了H2 L的 6种稀土配合物 ,并采用元素分析IR ,UV ,1 HNMR和DTA TG对配合物进行了表征。配合物的分子式为RE(HL2 )·4H2 O (RE =La ,Pr,Nd ,Eu ,Gd和Er) ,配体以四齿参与配位 ,配合物是八配位结构。此外用紫外光谱法测定了配合物对O2 -·自由基的清除率。结果表明邻羧基苯甲醛苯甲酰腙稀土配合物有一定的抗氧化活性 ,对O2 -·自由基的清除率在 8%~ 2 5 %范围内 相似文献
14.
Uppadine LH Gisselbrecht JP Kyritsakas N Nättinen K Rissanen K Lehn JM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(8):2549-2565
An extended family of heterometallic [(M1)2(M2)2(L-)4](n+) [2x2] grid-type arrays 1-9 has been prepared. The three-tiered synthetic route encompasses regioselective, redox and enantioselective features and is based on the stepwise construction of heteroditopic hydrazone ligands A-C. These ligands contain ionisable NH and nonionisable NMe hydrazone units, which allows the metal redox properties to be controlled according to the charge on the ligand binding pocket. The 2-pyrimidine (R) and 6-pyridine (R') substituents have a significant effect on complex geometry and influence both the electrochemical and magnetic behaviour of the system. 1H NMR spectroscopic studies show that the Fe(II) ions in the grid can be low spin, high spin or spin crossover depending on the steric effect of substituents R and R'. This steric effect has been manipulated to construct an unusual array possessing two low-spin and two spin-crossover Fe(II) centres (grid 8). Electrochemical studies were performed for the grid-type arrays 1-9 and their respective mononuclear precursor complexes 10-13. The grids function as electron reservoirs and display up to eight monoelectronic, reversible reduction steps. These processes generally occur in pairs and are assigned to ligand-based reductions and to the Co(III)/Co(II) redox couple. Individual metal ions in the heterometallic grid motif can be selectively addressed electrochemically (e.g., either the Co(III) or Fe(II) ions can be targeted in grids 2 and 5). The Fe(II) oxidation potential is governed by the charge on the ligand binding unit, rather than the spin state, thus permitting facile electrochemical discrimination between the two types of Fe(II) centre in 7 or in 8. Such multistable heterometallic [2x2] gridlike arrays are of great interest for future supramolecular devices incorporating multilevel redox activity. 相似文献
15.
JIANG Yinzhi & HU Weixiao . Department of Pharmaceutical Science Zhejiang University of Technology Hangzhou China . Department of Applied Chemistry Zhejiang Institute of Science Technology Hangzhou China 《中国科学B辑(英文版)》2004,47(3)
Rare earth complexes with organic ligands have been used as luminescence-material usually. Except their luminescent property, the complexes of trivalent lanthanide ions have low toxicity and powerful para-magnetic properties[1,2], so the lanthanide complexes are associated with important biological uses as diag-nostic tools and medicines[36]. Recently, there are some reports on Ce(III) complexes, some of which show anti-cancer activities[7]. S- tetrazines can be used as poly-dentate chelatin… 相似文献
16.
The title coordination compound with N-substituted-salicyl Schiff ligand, Cu(C15H12N2O3)(C5H5N), has been synthesized. The coordination compound crystallizes in orthorhombic system, space group Pbca with a=2.037 62(7) nm, b=0.698 45(2)nm, c=2.508 76(9)nm, V=3.570 4(2) nm3, Z=8, F(000)=1 688, Dc=1.529 g·cm-3, Mr=410.91, μ=1.250 mm-1, R=0.031 3 and wR=0.077 0. In the coordination compound, one phenolate oxygen, one carbonyl oxygen and one hydrazine nitrogen atom from the dianionic ligand N-salicylaldehyde-N′-(4-methoxybenzoyl) hydrazone and one pyridine nitrogen atom coordinate to Cu(Ⅱ) ion, forming a distorted square plane. CCDC: 218182. 相似文献
17.
Bhetanabhotla S. Sastry Jangala V. Rao Tippanu Thirupathi Rao Chilukuri S. P. Sastry 《Mikrochimica acta》1992,108(3-6):185-193
Four simple and sensitive visible spectrophotometric methods (A-D) for the determination of nitrofurazone in bulk samples and pharmaceutical formulations are described. They are based on the formation of colored species by treating either its reduction product with 3-methylbenzothiazolin-2-one hydrazone in the presence of ferric chloride (method A: max 600 nm) or its hydrolysis product with thiobarbituric acid (method B: max 520 nm, 440 nm) or barbituric acid (method C: max 400 nm) or by oxidizing it with excess N-bromosuccinimide and determining the consumed NBS using metol-isonicotinic acid hydrazide (method D: max 620 nm). 相似文献
18.
Potentiometric investigations on metal complexes of various bivalent metal ions, viz. UO2(II), Cu(II), Ni(II), Co(II), Cd(II), Pb(II), Zn(II) and Mn(II) with benzilmonol(lepidy!)hydrazone (BLH) have been carried
out at different ionic strengths and at different temperatures in order to determine stability constants of the complexes.
Thermodynamic parameters ΔC, ΔH and ΔS have also been evaluated from temperature coefficient data. The effect of varying the
dielectric constant of the medium on the stability constants of complexes has also been investigated at 30±0.5°C and μ = 0.1MNaCl.
Thermodynamic stability constants and thermodynamic stabilization energies for the first transition metals have also been
discussed. 相似文献
19.
合成了4个新型的含羧基酰腙类配体H2L^1~H2L^4,通过元素分析、TG-DTA、IR、摩尔电导等方法表征了它们与Pb(Ⅱ)配合物的结构,结果表明,配体以四齿形式与Pb(Ⅱ)形成了1:1的配合物,其中羧基以桥式方式参与配位. 相似文献
20.
《应用有机金属化学》2017,31(12)
A novel tridentate chelating ligand, Ethyl 2‐(2‐(2‐chlorobenzoyl)hydrazono)propanoate and its late transition metal complexes were synthesized, characterized and evaluated for anticancer behavior. The structures were elucidated with the help of elemental analyses, spectral (vibrational, electronic, NMR and mass) and thermo‐gravimetric techniques. Single crystal X‐ray crystallographic studies of the ligand suggest an orthorhombic lattice structure with Pna21 space group. The interaction of ligand and complexes with DNA (CT‐DNA) has been extensively studied using absorption, emission, viscosity and thermal denaturation studies with E. coli DNA. The DNA cleavage ability of ligand and metal complexes was tested using plasmid pBR322 DNA by gel electrophoresis method. The ligand and its copper complex have been evaluated for their in vitro anticancer activity against human cancer cells of different origin such as KB (Oral), A431 (Skin), Mia‐Pa‐Ca (Pancreases), K‐549 (Lung), K‐562 (Leukemia), MCF‐7 (Breast) and VERO by MTT assay and the apoptosis assay was carried out with acridine orange/ethidium bromide (AO/EB) staining method. The studies suggest that ligand and copper complex exhibit significant cytotoxic activity on KB, MCF‐7, A‐431, Mia‐Pa‐Ca‐2 an d A‐549 cell lines compared to K‐562 and VERO cell lines. 相似文献