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1.
《Analytical letters》2012,45(1-2):99-112
Abstract A spectrophotometric study of the Pd(II) complex of a reagent 2-(5-Bromo-2-Pyridylazo)-5-(diethylamino)-Phenol (5-Br-PADAP) is presented. A violet complex is formed at pH 3.53, and shows maximal absorbance at 585 nm with molar absorptivity of 3.86 × 104 1. mol?1 cm?1. Beer's law is obeyed up to 50 μ of Pd(II). The method offers the advantages of simplicity, high precision, requires no extraction and is very selective, where 5.0 mg Pt(VI) and 0.3 mg Au(III) ions do not interfere. 相似文献
2.
《Analytical letters》2012,45(14):2951-2961
ABSTRACT A highly sensitive azo dye, 2-(5-nitro-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (Nitro-PAPS), is used as a colorimetric reagent for the determination of tin(IV) content. Nitro-PAPS reacts with tin(IV) to form a water-soluble complex in 1.0 M acetic acid. Full color development is attained within 5 minutes, and maintains constant absorbance for at least 24 hours. The apparent molar absorptivity is 7.7 x 104 dm3 mol?1 cm?1 at a maximum wavelength of 580 ran. Beer's law is obeyed for tin(IV) in the range of 0-1.2 μg ml?1. The proposed method is successfully applied to the determination of trace amounts of tin in steels. 相似文献
3.
以2-氨基-5-取代苯氧甲基-1,3,4-噻二唑(1)为起始原料, 合成了中间体2-氯乙酰氨基-5-取代苯氧甲基-1,3,4-噻二唑)-2-乙酰亚胺(2)和2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-4-噻唑啉酮(3), 化合物3进一步与取代苯甲醛发生类Knoevenagle缩合反应, 得到了一系列2-(5-取代苯氧甲基-1,3,4-噻二唑-2-亚胺基)-5-(取代苯基亚甲基)-4-噻唑啉酮类化合物4a~4p. 目标化合物4a~4p的结构经IR, 1H NMR和元素分析确证. 相似文献
4.
《Analytical letters》2012,45(7-8):713-723
Abstract Hafnium(IV) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the pH range 3.3–11.0 to yield a sparingly soluble red-coloured chelate that can be dissolved with Triton X-100. Effect of initial pH of metal ion and order of addition of reagents was studied in detail. The 1:3 complex adheres to Beer's law over the concentration range 0.02–1.12 μg/ml of Hf(IV), has a molar absorptivity 1.33x105 1 mol?1cm?1, Sandell sensitivity 1.3 ng cm?2, formation constant (log K) 11.94 and the method had a relative standard deviation of ± 1.5%. Effect of 60 diverse ions on the determination of hafnium(IV) was studied. This fairly selective method is the most sensitive so far reported for the spectrophotometric determination of hafnium(IV). 相似文献
5.
Wei Wang Min-Zhen Mao Xiao-Guang Zhang Xiao-Rui Zheng Xiao-Ying Huang 《Phosphorus, sulfur, and silicon and the related elements》2018,193(3):164-167
A series of novel ethyl 2-(5-methyl-3-arylisoxazole-4-carboxamido)-4-alkylthiazole-5-carboxylates I-1-6 were synthesized. The structures of all target compounds were characterized by 1H NMR, 13C NMR, IR, MS and elemental analyses. Their fungicidal and herbicidal activities were evaluated. The results of preliminary bioassays show that the title compounds I-4 possess 20–50% inhibition against most of the tested plants at the dosage of 150 g ai/ha, while the title compounds I-1-5 possess 32–58% inhibition against FusaHum graminearum, Thanatephorus cucumeris, Botrytis cinereapers and Fusarium oxysporum in vitro at the concentration of 100 mg/L. 相似文献
6.
《Analytical letters》2012,45(7):1013-1027
Abstract Nine new hydroxamic acids in conjunction with four pyridylazo reagents were explored for extractive separation and spectrophotometric determination of palladium in environmental samples. It was found that maximum sensitivity and selectivity was achieved by employing N-p-methoxyphenyl-2-furylacrylohydroxamic acid (MFHA) and 5-(diethylamino)-2-(2-pyridylazo) phenol (DEPAP). Palladium was first selectively extracted with MFHA in isoamyl alcohol at pH 2.7-3.5 and the extract was equilibrated with a mixture of 5 M HCl and 10? 3 M solution of DEPAP in ethanol. The resulting intensely green ternary complex was measured at 560 nm (σ 5.1 × 104 l mole?1 cm?1). The extraction system is suitable for enrichment of palladium over 15 times without loss in recovery and enables determination of palladium at levels as low as 10?4 ppm (0.1 ppb). The method tolerates the presence of a large number of diverse ions normally associated with palladium, including platinum metals, and was employed for the determination of palladium in standard catalysts, biological materials, and freshwaters. 相似文献
7.
The behaviour of the vanadium(V) complex with 5-Br-PADAP at a mercury electrode was investigated in HOAcNaOAc. The adsorption phenomena were observed by linear-sweep voltammetry. The mechanism of the electrode reaction was found to be the irreversible reduction of the V(V) in the complex adsorbed on the surface of the electrode to the V(IV) complex with 5-Br-PADAP. In 0.02 mol l?1 HOAc-0.012 mol l?1 NaOAc (pH 4.5) and 1 × 10?6 mol l?1 5-Br-PADAP, the detection limits of linear-sweep adsorption voltammetry and 1.5th-order derivative adsorption voltammetry are 5 × 10?10 and 2.5 × 10?11 mol l?1 , respectively. The method was applied to samples of ore (Geological Deposit). 相似文献
8.
The molecular and electronic structure of hypothetical metallofullerenes In5C55 (1a) and In10C60 (2a) were simulated by the MNDO/PM3 method. Formally, heterofullerene1a is obtained from the C60 cluster by replacement of the carbon atoms at α-positions relative to one of the pentagons by In atoms, and cluster2a is obtained from the C70 cluster by replacement of the carbon atoms framing the polar pentagons of this fullerene by In atoms. Along with clusters1a and2a, their η5-π-complexes ln(η5-1a (1b) and ln2(2η5-2a) (2b) with one (1b) and two (2b) exohedral In atoms coordinated to the pentagons (pent
*) isolated by In atoms were also studied. The energies of the In—pent
* bonds in1b and2b are approximately equal to 104 kcal mol−1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 880–883, May, 1998. 相似文献
9.
K. K. Vijaya Raj B. Narayana 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1971-1981
A smooth one-step synthesis of 2-(2-bromo-5-methoxyphenyl)-5-(3-arylidene)-1,3-thiazolo[3,2-b]-1,2,4-triazol-6-(5H)-ones (4a–n) is described. The newly prepared compounds are characterized by analytical and IR, 1 H NMR, 13 C NMR, and FABMS spectral analysis. A few compounds are screened for anticonvulsant activity. Compounds 4i and 4n exhibit promising anticonvulsant activity and are recommended for further studies. 相似文献
10.
1,2-Bis-[(5-methyl)-2-1H-benzimidazolyl]- (L
1), 1,2-bis-[(5-chloro)-2-1H-benzimidazolyl]- (L
2), 1,2-bis-[(5-nitro)-2-1H-benzimidazolyl]-1,2-ethanediol (L
3) and their PdCl2 complexes were synthesized and characterized by elemental analysis, molar conductivity, i.r. and 1H-n.m.r. spectra. The benzene ring substituents lead to a decrease in melting point. The methyl group reduces the solubility and the acidity of L
1 and Pd(L
1)Cl2, whereas the Cl and NO2 groups increase the solubility and the acidity of L
2, L
3, Pd(L
2)Cl2 and Pd(L
3)Cl2. In Pd(L
1)Cl2 and Pd(L
2)Cl2 complexes, the ligands act as a bidentate through two nitrogen atoms. In Pd(L
3)Cl2, ligand coordination occurs through one OH group oxygen atom and one of the benzimidazole nitrogen atoms. 相似文献
11.
A new highly sensitive and selective chromogenic reagent, 2-(2,5-disulfonic-4-methoxyphenylazo)-7-(2-hydroxyl-5-carboxylphenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic
acid (1), was synthesized and applied to the spectrophotometric determination of trace thorium. In 5 mL of a 6 M perchloric acid
medium, which greatly increases the selectivity, thorium reacts with 1 to form a 1: 2 green complex, having a sensitive absorption peak at 670 nm. Under optimal conditions, Beer’s law is obeyed
over the range from 0 to 0.8 μg/mL Th(IV) and the apparent molar absorptivity is 2.09 × 105 L/mol cm. It is found that, uranium(VI), Ti(IV), heavy rare earths, and most of other common metal ions do not interfere.
The method has been tested on the determination of thorium in food samples with satisfactory results.
The text was submitted by the authors in English. 相似文献
12.
Determination of titanium by adsorption-voltammetry with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP) 总被引:1,自引:0,他引:1
Summary The 1:1 complex between titanium (IV) and 5-Br-PADAP can be used to determine titanium by adsorption voltammetry at a stationary Hg-electrode. The experimental conditions for the determination are described. The detection limit is 3×10–10 mol/l Ti (0.015 ppb). Calibration curves are linear for solutions containing 4×10–10 to 5×10–8 mol/l Ti(IV) and an enrichment time of 3 min. The influence of foreign ions was investigated. The determination can be carried out in the presence of a 5000-fold excess of iron. 相似文献
13.
Ali Z. Abu-Zuhri 《Microchemical Journal》1984,29(3):345-349
A spectrophotometric study of the Th(IV) complex of a new reagent 2-(5-Bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) is presented. A reddish brown complex is formed at pH 4.86, and shows maximal absorbance at 580 nm with molar absorptivity of 1.66 × 105 mol−1 cm−1 liter. Beer's law is obeyed over the range 0.0 to 15 μg of thorium. Rare earths ions like La3+, Ce3+, and Y3+ do not interfere because they form complexes with 5-Br-PADAP at higher pH's (>9.94) (1). A new method for determining trace amounts of thorium is proposed, which possesses the advantages of high sensitivity and selectivity. 相似文献
14.
2-取代硫醚-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑类化合物的合成、结构与体外抗癌活性 总被引:19,自引:0,他引:19
以天然产物没食子酸为原料经醚化、酯化、酰肼化、成盐、闭环、硫醚化六步反应合成了6个2-取代硫醚-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑类衍生物, 釆用铟催化下水相合成目标化合物8, 具有反应条件温和, 合成收率高的特点; 用IR, 1H NMR, 13C NMR和元素分析对各化合物进行了表征及结构确证, 并用X射线单晶衍射法测定了化合物8a [2-(2-氯-5-吡啶甲基)硫醚-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑]的晶体结构, 采用MTT法进行了新化合物抑制PC3和BGC-823癌细胞体外试验, 结果表明在5μmol•L-1浓度下化合物8e对PC3的抑制活性为55.71%. 化合物8b对BGC-823细胞抑制活性为66.21%. 相似文献
15.
1-[5-(1,3-二氧-4,5,6,7-四氢-1H-异吲哚-2-基)苯基]-3-取代脲衍生物的合成与除草活性研究 总被引:1,自引:0,他引:1
为了寻找高效低毒的原卟啉原氧化酶抑制剂(protox)类除草剂, 设计并合成了一系列1-[5-(1,3-二氧-4,5,6,7-四氢-1H-异吲哚-2-基)苯基]-3-取代脲类衍生物4a~4d和5a~5g. 化合物4a~4d经异氰酸酯法合成, 收率、纯度高; 化合物5a~5g利用固体光气一锅法合成, 反应时间短.所得化合物结构经1H NMR, IR, 质谱和元素分析表征. 初步生物活性测试表明: 化合物4c, 5a, 5b, 5c在有效成分75 g/hm2 剂量下对苘麻、马刺苋、凹头苋等双子叶杂草表现出90%以上的防效. 相似文献
16.
A. R. Jalilian M. Sheikhha M. Mirzaei G. R. Aslani A. Shafiee 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(2):373-377
5-[2-(2-Chlorophenoxy)phenyl]-1,3,4-oxadiazole-2-yl-4-fluorobenzoate 6a, the non-classic benzodiazepine ligand, has been shown to elicit a significant anticonvulsant activity against pentylenetetrazole-induced
convulsion. In order to perform biological studies, we decided to prepare the [18F]-labeled compound. This compound was prepared in no-carrier-added (n.c.a) form from 5-[2-(2-chlorophenoxy)phenyl]-1,3,4-oxadiazole-2-yl-4-N,N,N-trimethylanilinium
triflate 5 in one step at 125 °C in Kryptofix 2.2.2/[18F] and DMSO as the solvent followed by column chromatography. The synthesis took 20 minutes with an overall radiochemical
yield of 70-75% (EOS) and a specific activity about 74 GBq/mmole and chemical-radiochemical purity more than 95%.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Abdallah Harizi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2377-2385
The phosphonomethylhydrazide 2a reacts with N-acylated imidates 3a–d to give the corresponding 5-aryl (or 5-benzyl)-2-[(1-diethoxyphosphonyl)methyl]-1,3,4-oxadiazoles 4a–d after the elimination of ethanamide 5. Compounds 2a–e are prepared by the action of triethyl phosphonoacetate 1 with hydrazine and its derivatives. The structures of 1,3,4-oxadiazoles 4a–d and hydrazides 2a–e have been unequivocally confirmed by means of IR, 1 H, 13 C, 31 P NMR and mass spectrometry. 相似文献
18.
Akbar Mobinikhaledi Naser Foroughifar Somayeh Faghihi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1837-1842
Treatment of 2-aminopyridine ( 1 ) with chloroacetyl chloride in dry benzene gave 2-chloro-N-(pyridin-2-yl)acetamide ( 3 ), which on further reaction with potassium thiocyanate gave 2-imino-3-(pyridin-2-yl)thiazolidin-4-one ( 4 ) as an intermediate compound for the synthesis of pyridin-2-yl substituted 2-imino-thiazolidine-4-one derivatives. Cyclocondensation reaction of ( 4 ) with a series of aromatic aldehydes gave 5-arylidene derivatives of pyridin-2-yl substituted 2-imino-thiazolidine-4-ones 5a–j . 1 H and 13C NMR spectroscopy, as well as elemental analyses, were used for the identification of these new compounds. 相似文献
19.
Cadmium(II) reacts with 2-[2-(5-bromopyridyl)azo]-5-dimethyl-aminophenol (5-Br-DMPAP) in aqueous solution; the complex can be extracted with organic solvents such as chloroform, 3-methyl-l-butanol and methyl isobutyl ketone at pH 8–10.5 to give a red solution which absorbs at 525–555 nm. The absorbance in organic solvents is stable and the system conforms to Beer's law; the optimal range in 3-methyl-1-butanol for measurement in 1.00-cm cells is 0.01–l p.p.m. cadmium. Moderate amounts of many cations and anions do not interfere, and interfering cations such as zinc, copper, manganese and nickel can be separated by extraction with dithizone. The 5-Br-DMPAP method is one of the most sensitive procedures available for the determination of cadmium; the molar absorptivity in a 3-methyl-1-butanol extract is 1.41·105 1 mol?1 cm?1 at 555 nm. 相似文献
20.
超声辐射下合成1-[(未)取代苯酰基-3-[5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑-2-基]-硫脲 总被引:2,自引:0,他引:2
1-苯基-3-甲基-5-氯吡唑-4-甲酸与氨基硫脲在三氯氧磷中反应得到2-氨基-5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑(1), 然后分别采用超声辐射法和常规加热法与(未)取代苯甲酰基异硫氰酸酯(2)反应合成了一系列未见报到的1-[(未)取代苯酰基-3-[5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑-2-基]-硫脲(3a~3j). 化合物的结构经元素分析, IR, 1H NMR确证. 相似文献