Thiotropolone as a Chromogenic Reagent for the Microdetermination of Copper(II)

Thiotropolone forms a brown water-insoluble complex with copper(II), extracttable into chloroform and other non-polar solvents. The 1:2 complex shows maximum absorption at 450 nm and obeys Beer's law upto 4.55 ppm. The sensitivity of the reaction is 0.0046 μg Cu(II)/cm² for log I₀/I=0.001 with molar absorptivity of 1.36×10⁴. The usefulness of the procedure has been enhanced to the determination of copper in various alloys and synthetic mixtures.     

4-Acetylpyridine 2-Benzothiazolylhydrazone as a Chromogenic Reagent for Common Epoxides

Abstract

A simple and sensitive color reaction of common epoxides as well as other some alkylating agents with 4-acetylpyrldine 2-benzothiazolylhydrazone (ABH) is described. These compounds gave a purpllsh red color after reaction with ABH for 2 hrs at 110°C in methyl cellosolve or for 20 min at 120°C followed by treatment with plperazlne on silica gel thin-layer plates. Four aliphatic terminal epoxides could be determined spectrophotometrically in the range from 20 to 125 nmol/ml. The limits of detection of these epoxides on silica gel thin-layer plates were 10 pmol/spot order by the visual inspection. The reaction mechanism is also discussed based on the chemical structure of the isolated chromophore.     

邻磺酸基苯偶氮若丹宁流动注射分光光度法测定钯(Ⅱ)

本文报道了应用邻磺酸基苯偶氮若丹宁（ｏ－ＳＢＡＲ）试剂流动注射分光光度法测定钯的新方法。以（１＋１）的磷酸溶液为载体,试剂ｏ－ＳＢＡＲ与钯（Ⅱ）在反应管内迅速反应生成桔红色的络合物,其最大吸收波长为５２１ｎｍ。大量的碱金属、碱土金属及常见有色金属离子不影响,除Ａｕ＾３＋和Ｒｕ＾３＋干扰外,其他贵金属离子也有一定的允许量。此方法进样频率为８１次／小时,测定钯（Ⅱ）的线性范围为０．１～４．０μｇ／ｍＬ     

Complexometric Determination of Mercury(II) Using 2-Mercaptopropionylglycine as a Selective Masking Reagent

 A selective complexometric method for the determination of mercury(II) in the presence of associated metal ions is reported, based on the selective masking ability of 2-mercaptopropionylglycine (MPGH₂) towards mercury. Mercury, along with other associated metal ions, is first complexed with excess of EDTA and the surplus EDTA is back titrated at pH 5–6 (hexamine buffer) with standard zinc sulfate solution using xylenol orange as indicator. An aqueous 1% solution of MPGH₂ is then added to displace EDTA selectively from the Hg-EDTA complex and the released EDTA is titrated with the same standard zinc sulfate solution. Reproducible and accurate results are obtained for 4–85 mg of mercury with a relative error of ≤ 0.26% and coefficient of variation not exceeding 0.42%. The interferences of various cations and anions are studied. The method is used for the analysis of mercury in its complexes and alloy samples. Received August 30, 2000. Revision January 15, 2001.     

A Simple Sensitive Spectrophotometric Method for the Determination of Ce4+ Using Variamine Blue as a Chromogenic Reagent

A rapid and sensitive spectrophotometric method is described for the determination of trace amounts of cerium using Variamine Blue (VB) as a chromogenic reagent. The proposed method is based on the reaction of cerium with potassium iodide in acidic medium to liberate iodine, which oxidizes Variamine Blue to give a violet colored species with an absorption maximum at 560nm. Beers law was obeyed in the range 2–10µg mL^–1 of cerium. The molar absorptivity and Sandells sensitivity are found to be 1.65×10⁴L mol^–1cm^–1 and 8.48×10^–3µgcm^–2, respectively. The proposed method has been successfully applied to the determination of cerium in alloy and synthetic mixtures.     

Isonitroso-4-Methyl-2-Pentanone for Solvent Extraction and Spectrophotometric Determination of Palladium (II) at Trace Level

Abstract

Isonitroso-4-methyl-2-pentanone (HIMP) is proposed as a new reagent for extraction and photometric determination of Pd(II). The reagent forms a yellow complex with palladium in the pH range 4.0-5.0. The complex extracted into chloroform was measured at 330 nm. The molar absorptivity was found to be 5.37 × 10³ 1 mol^?1 cm^?1 and Sandell's sensitivity 20 ng cm^?2 Beer's law was obeyed over the concentration range 0.1-10.0 μg/ml of palladium. The method is applicable for palladium estimation in Ores and catalysts.     

Ruthenium(II) and Osmium(II) Vinyl Complexes as Highly Sensitive and Selective Chromogenic and Fluorogenic Probes for the Sensing of Carbon Monoxide in Air

The detection of carbon monoxide in solution and air has been achieved using simple, inexpensive systems based on the vinyl complexes [M(CH?CHR)Cl(CO)(BTD)(PPh₃)₂] (R=aryl, BTD=2,1,3‐benzothiadiazole). Depending on the nature of the vinyl group, chromogenic and fluorogenic responses signalled the presence of this odourless, tasteless, invisible, and toxic gas. Solutions of the complexes in CHCl₃ underwent rapid change between easily differentiated colours when exposed to air samples containing CO. More significantly, the adsorption of the complexes on silica produced colorimetric probes for the naked‐eye detection of CO in the gas phase. Structural data for key species before and after the addition of CO were obtained by means of single X‐ray diffraction studies. In all cases, the ruthenium and osmium vinyl complexes studied showed a highly selective response to CO with exceptionally low detection limits. Naked‐eye detection of CO at concentrations as low as 5 ppb in air was achieved with the onset of toxic levels (i.e., 100 ppm), thus resulting in a remarkably clear colour change. Moreover, complexes bearing pyrenyl, naphthyl, and phenanthrenyl moieties were fluorescent, and greater sensitivities were achieved (through turn‐on emission fluorescence) in the presence of CO both in solution and air. This behaviour was explored computationally using time‐dependent density functional theory (TDDFT) experiments. In addition, the systems were shown to be selective for CO over all other gases tested, including water vapour and common organic solvents. Supporting the metal complexes on cellulose strips for use in an existing optoelectronic device allows numerical readings for the CO concentration to be obtained and provision of an alarm system.     

Synthesis,Structure and Photochromic Properties of 1-Phenyl-3-Methyl-4-(4-Bromobenzal)-Pyrazolone-5 Thiosemicarbazone

A new organic photochromic compound containing pyrazolone-ring, 1-phenyl-3-methyl-4-(4-bromobenzal)-pyrazolone-5 thiosemicarbazone (PM4BrBP-TSC), was synthesized and characterized by elemental analyses and single crystal X-ray diffraction. The X-ray determination indicated that PM4BrBP-TSC is of orthorhombic system, space group Pbca with cell dimensions of a = 12.184(2) Å, b = 18.121(3) Å, c = 18.554(4) Å, V = 4096.4(12) ų, Z = 8 and R = 0.0387. The photochromic properties and photocolored kinetics of PM4BrBP-TSC were studied by Time-dependent UV-Vis reflectance spectra and fluorescence spectra under 365 nm light irradiation. The crystal structure analysis showed that the photochromic properties were related to the photoisomerization from enol tautomer to keto one.     

新显色剂1-(2-咪唑偶氮)-2-萘酚-4-磺酸作为络合滴定指示剂的研究

本文报道了新显色剂1-(2-咪唑偶氮)-2-萘酚-4-磺酸(IANS)的物理性质、酸离解常数,并对该试剂作为EDTA络合滴定Cu~(2+)、Zn~(2+)、Pb~(2+)、Cd~(2+)、和Hg~(2+)的指示剂进行了研究,结果与二甲酚橙比较令人满意。     

N-2-Pyridinylmethyl-N'-arylmethyl-diaminomaleonitriles: New Highly Selective Chromogenic Chemodosimeters for Copper(II)

Copper chemodosimeters: The copper(II)-promoted air oxidation of 1-3 to form 4-6 permits the highly selective colorimetric detection of Cu(2+) ions. The formation of copper(II) complexes of 4-6 proceeds rapidly, and the chemodosimeters 1-3 are viable at physiological pH.     

2-二异丙氨基-3-甲基-5-(4-二甲氨基偶氮苯)-1,3,4-噻二唑作为光度法显色剂的可能性

噻二唑偶氮类化合物作为光度显色剂迄今未见报道。我们合成了2-二异丙氨基-3-甲基-5-(4-二甲氨基偶氮苯)-1,3,4-噻二唑(见下式),简称为TDAA-Ⅰ。     

Cyclohexane-1, 3-Dione bis (4-Methylthiosemicarbazone) as a Spectrophotometric Reagent for the Determination of Zn (II)

Abstract

The spectrophotometric study of reddish cyclohexane-1, 3-dione bis (4-methylthiosemicarbazone)-Zn(II) was made in dimethylformamide-water solution (λ_max= 475 nm, ∑ = 3.3×10⁴ 1.mole^?1. cm^?1. Sandell sensitivity = 2×10^?2 μg Zn(II).cm^?2, stoichiometry 1:1, and apparent stability constant 6.1×10⁴). A new method for the spectrophotometric determination of Zn(II) is proposed for concentrations between 0.1 and 2.5 ppm. The relative error (95% confidence level) is 0.7% for 1.0 pprn of Zn(II).

The extraction with ethylacetate of the reddish complex was also studied spectrophotometrically (λ_max = 493 nm, ∑ in organic phase = 4.8×10⁴ 1.mole^?1.cm. Sandell sensitivity = 3.4×10^?4 μg Zn(II).cm^?2, stoichiometry 1:1, apparent extraction constant 1.4×10⁴). A new method for the extraction-spectrophotometric determination of Zn(II) is proposed for concentrations, in aqueous phase, between 0.02 and 0.30 ppm. The relative error (95% confidence level) is 1.0% for 0.15 pprn of Zn(II).     

Catalytic Synthesis of 2-Methyl-1,4-Naphthoquinone (Vitamin K3) Over Silica-Supported Aminomethyl Phosphine-Ru(II), Pd(II), and Co(II) Complexes

Ru(II), Pd(II), and Co(II) complexes of the free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl)aminopropyltriethoxysilane [(EtO)₃Si(CH₂)₃ N(CH₂PPh₂)₂] (DIPAPTES), and its SiO₂-DIPAPES have been synthesized under a nitrogen atmosphere using Schlenk techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to give 2-methyl-1,4-naphthoquinone (vitamin K₃, menadione, 2MNQ) in the presence of hydrogen peroxide as a clean and cheap oxidant. The catalytic synthesis of vitamin K₃ was investigated using both homogeneous catalysis with free complexes and heterogeneous catalysis with silica-supported complexes. [(DIPAPTES)PdCl₂] and its silica-supported form showed the best catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphtoquinone compared to the other metal complexes. 2MNQ yield reached 52.26% with the 2MN conversion of 90.52% using complex [(DIPAPTES)PdCl₂] and 58.59% with the 2MN conversion of 99.56% using the silica supported [SiO₂(DIPAPES)PdCl₂] complex for 1 h. Recycling was investigated for the silica-supported Pd(II) complex and compared with the classical production of vitamin K₃.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Astraphloxin Cyanine Dye as a Reagent for the Selective Extraction-Photometric Determination of Trace Mercury(II)

A procedure was developed for the extraction-photometric determination of low concentrations of mercury(II) in aqueous solutions. It is based on the reaction of the Hg Br ₃ ^? acidocomplex with the Astraphloxin cationic dye to give an ion pair extracted with toluene. The detection limit for mercury is 0.015 mg/L. Effects of a number of heavy metal cations on determining mercury(II) were studied. It was shown that these effects appear in the presence of 500-fold molar amounts of interferents. The procedure was used for determining mercury(II) in the presence of 200-fold molar amounts of some heavy metal cations. The relative standard deviation was no worse than 5%.     

The Reaction of Triplet 2-Methyl-1,4-Naphthoquinone (Menadione) with DNA and Polynucleotides

Abstract— The photoreaction of 2-methyl-l,4-naphthoquinone (MQ, menadione) with DNA and polynucleotides in argon-saturated aqueous solution (pH 7) was studied. Results from laser flash photolysis experiments indicate that triplet quinone reacts with DNA and polyA but not detectably with polyU by one-electron oxidation of the bases of the nucleic acid with formation of the radical anion of the quinone. Irradiation of argon-saturated solutions containing MQ and DNA or polynucleotides (polyU, polyA, polyG or polyC) with 334 nm light leads to an increase in molecular weight for single-stranded DNA, polyA and to a much less extent for polyU. This finding indicates crosslink formation with quantum yields in the range of 10⁻⁵-10⁻³     

藉聚2-丙烯胺缩-3-(4-甲酰基苯偶氮)-4,5-二羟基-2,7-萘二磺酸分光光度法测定生物体液、食品和饮品中的镁

聚2-丙烯胺缩3－（4-甲酰基苯偶氮）-4，5-二羟基-2，7-萘二磺酸（PA-FPNS）在pH11．5的磷酸盐介质中．与镁（Ⅱ）形成一蓝色络合物，其最大吸收位于604nm，表观摩尔吸光系数ε=5．7×104L·mol-1·cm-1，线性范围为0．01～0．35mg／L，至少稳定12h。考察了30多种共存离子的影响，在所测样品中它们不干扰，无需掩蔽或分离即可直接测得其中的镁。     

Spectrophotometric Determination of Palladium by the New Chromogenic Reagent N-Butyl - N'-(Sodium P-Aminobenzenesulfonate) Thiourea

Abstract

A highly sensitive spectrophotometric method for determination of palladium by the new chromogenic reagent (BPT) has been developed. In the presence of cetyltrimethylammonium bromide(CTMAB), palladium reacts with BPT to form a stable yellow complex in HAc-NaAc buffer solution of pH 4.6-5.6 at 294.4 nm with a molar absorptivity of 2.46 x 10⁵ l mol^?1 cm^?1. The method is simple, rapid and sensitive. Trace amounts of palladium in mineral and catalyst samples have been satisfactorily determined by the method.     

A Sensitive Catalytic-Photometric Method for the Determination of Trace Amounts of Palladium(II) by Using a Computerized Probe-Type Photometer1, 2

A simple and sensitive catalytic-photometric method for the determination of trace amounts of palladium(II) based on its heterogeneous catalytic effect on the reduction of neutral red (NR) by hypophosphite (HP) has been developed. The reaction was monitored at 530 nm and the time elapsed (At) for the absorbance to decrease from its initial value by 1.5 absorbance units was recorded using the variable time method. The influence of reaction variables is discussed. The ranges of linearity were 0.108–6.533 ppm and 0.032–0.653 ppm palladium(II) at temperatures of 30 and 55°C, respectively. The relative standard deviations of the developed method were 2.5 and 2.7% (for 8 replicate determinations of 1.110 ppm Pd(II)) at 30 and 55°C, respectively. The effect of interferences from other metal ions and some anions was studied. The developed method has been successfully tested for determination of Pd(II) in Al–Si–Pd catalysts.