Spectrophotometric determination of manganese with derivatives of 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3- H-indol-2-ylidene)propenyl]-3 H-indolium

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of manganese in sewage. The method is based on the reaction of manganese with derivatives of 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3-H-indol-2-ylidene)propenyl]-3H-indolium to form a colored ion associate with a sensitive absorption maximum at 560 nm. The appropriate reaction conditions have been established: pH 8.5–10.0, 1.25–2.3×10^–3 mol L^–1 1-nitroso-2-naphthol, and 1.6–2.4×10^–4 mol L^–1 dye reagent. Beer's law is obeyed for manganese concentrations up to 4.2 mg L^–1. The limit of detection is 0.01 mg L^–1 Mn²⁺; the molar absorptivity of the ion associate was 7.5×10⁴ L mol^–1 cm^–1. The effect of various foreign ions was examined. A reaction mechanism is suggested. The developed procedure was tested for determination of manganese in sewage with satisfactory precision and accuracy.     

Synthesis of 3-(2-amino-2-carboxyethyl)-2-carboxy-7-chlorobenzofuran

Two methods for the synthesis of 3-(2-amino-2-carboxyethyl)-2-carboxy-7-chlorobenzofuran are proposed.Faculty of Chemistry, N. Copernicus University, Torun 87–100, Poland. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1048–1050, August, 1997.     

Saure Hydrolyse von 2-(4-Chlorphenylazo)-2-(N-carbamidino-ureido)-propan

Zusammenfassung Die saure Hydrolyse der Arylazo-Verbindung1 wird beschrieben und interpretiert: Als Zwischenprodukte werden ungeladenes Aryldiazen (Ar–N=N–H) sowie zwitterionisches Aryldiazen (Ar–NH⁺=N:^–)und im weiteren Verlauf des Reaktionsgeschehens 1,4-Diaryltetrazenimionen postuliert.

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Acid hydrolysis of 2-(4-Chlorophenylazo)-2-(N-carbamidinoureido)-propane

Acid hydrolysis of the arylazo compound1 is described and discussed. As reaction intermediates uncharged aryldiazene (Ar–N=N–H) as well as zwitterionic aryldiazene (Ar–NH⁺=N:^–) and subsequently 1.4-diaryltetrazenium ions are postulated.

     

Cyclodextrin Complexation of the Stilbene 4-(2-(4-Tert-butylphenyl)ethen-1-yl)- benzoate and the Self-assembly of Molecular Devices

E-4-(2-(4- tert - butylphenyl) ethen-1- yl)benzoate, E-1^–, photoisomerizes to the Z-1^– isomer and vice versa in the free state and in the binary complexes 2·E-1^–, 2·Z-1^–, 3·E-1^– and 3·Z-1^– where 2 is the urea-linked cyclodextrin N-(6 ^A -deoxy--cyclodextrin-6 ^A - yl)-N-(6 ^A -deoxy--cyclodextrin-6 ^A - yl)urea and 3 is N,N- bis(6 ^A -deoxy--cyclodextrin-6 ^A - yl)urea. In 2·E-1^–and 3·E-1^– the stilbene occupies both cyclodextrin (CD) components of 2 and 3, whereas in 2·Z-1^– and 3·Z-1^– it only occupies one CD component while the other CD component is unoccupied. 4- tert - Butylphenolate, 4^–, and its carboxylate, 5^–, and sulfonate, 6^–, analogues form the ternary complex 2·Z-1^–·4^– and its analogues and also 3·Z-1^–·4^– and its analogues. These photoisomerize to 2·E-1^–and 3·E-1^– and either free 4^–, 57^– or 6^– and thereby function as molecular devices.     

2-(5-Nitro-2-Pyridylazo)-5-(N-Propyl-N-Sulfopropylamino)Phenol as a new analytical reagent for flow-injection spectrophotometric determination of trace vanadium(V)

A flow injection method using 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol-(Nitro-PAPS) as a new chromogenic reagent is presented for sensitive and rapid determination of vanadium. Nitro-PAPS reacts with vanadium(V) in weakly acidic medium to form a water soluble complex of molar absorptivity of 8.0 × 10⁴L mol^–1 cm^–1 at 592 nm (maximum absorption wavelength), which permits the straightforward application of a flow injection system to the sensitive determination of vanadium. Under the optimum conditions established, a linear calibration graph was obtained in the range 1–120 ng mL^–1. The relative standard deviation for 60 ng mL^–1 vanadium was 2.2% (n = 5) and the limit of detection was 1 ng mL^–1. The sample throughput is about 40 h^–1. Most inorganic and organic anions examined did not interfere even at concentrations of 3000–6000 times of vanadium. Interference from cobalt(II), copper(II) and nickel(II) at 200ng mL^–1 levels can be overcome by the addition of N-(dithio-carboxy)sarcosine. The recoveries for each 20 and 10 ng mL^–1 vanadium added to the river water were 98 and 97%, respectively.The authors express their thanks to Miss Miho Suzuki and Miss Hiroyo Yamada for their experimental assistance in part.     

Investigation of 2-[(<Emphasis Type="Italic">E</Emphasis>)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium as a new highly sensitive reagent for the spectrophotometric determination of nitrophenols

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of nitrophenols [picric acid (PA); dinitrophenols (DNP)] in wastewater samples. The method is based on the reaction of nitrophenols with 2-[(E)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3 H-indolium chloride reagent to form the colored ion associates, which are extracted by organic solvents. The molar absorptivity of the ion associates of PA with the investigated reagent ranges from 8.3×10⁴ to 11.3×10⁴ L mol^–1 cm^–1, depending on the extractant. Because only PA is extracted in an acidic medium with the investigated reagent, but both PA and DNP are extracted in an alkaline medium, it is possible to determine both substances in a mixture. Appropriate reaction conditions have been established. The absorbance of the colored extracts obeys Beers law in the range of 0.04–4.58 mg L^–1 PA, 1.0–18.4 mg L^–1 2,4-DNP and 1.2–14.7 mg L^–1 2,6-DNP, respectively. The limit of detections, calculated from a blank test (n=10; P=0.95), are 0.05 mg L^–1 PA, 0.9 mg L^–1 (2,4-DNP), and 1.1 mg L^–1 (2,6-DNP), respectively.     

Oxidation of 1-(4-nitrophenyl)-2-formylpyrrole

Pyrrole aldehydes interact with oxidizing agents to yield products which are oxidized to different degrees. Pyrrolecarboxylic acids are formed under the influence of silver oxides, an alkaline solution of permanganate, and 2–10% sulfuric acid [1–3]. With peroxidation of hydrogen, 5-unsubstituted pyrrole aldehydes convert to pyrrolone [4], and pyrrol-2-aldehyde converts to succinimide [5]. Chromacetate and chromium sulfuric acids oxidize pyrrole aldehydes to maleinimides [3].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 495–499, April, 1982.     

Spectrophotometric determination of cadmium with 1-[(5-chloro-2-pyridyl)azo]-2-naphthol

Summary Cadmium(II) reacts with l-[(5-chloro-2-pyridyl)azo]-2-naphthol (5-C1--PAN) in aqueous solution; the complex can be extracted with chloroform at pH 9–11 to give a red solution with an absorption peak at 566 nm. The colour in chloroform is stable and the system conforms to Beer's law; optimal range in the chloroform layer for measurement at 1.00-cm cells is 0.1–1 ppm cadmium. Common cations and anions do not interfere. Large amounts of some cations can be masked by potassium cyanide, the cadmium cyanide complex being demasked by formaldehyde. The proposed method is one of the most sensitive procedure for the determination of cadmium. The molar absorptivity in the chloroform extract is 6.6· 10⁴ 1 mole^–1 cm^–2 at 566 nm.

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Zusammenfassung Cadmium reagiert mit 1-(5-Chlor-2-pyridyl) azo-2-naphthol, 5-C1--PAN, in wäßriger Lösung; der rote Komplex kann bei pH 9–11 mit Chloroform extrahiert werden und hat ein Absorptionsmaximum bei 566 nm. Die chloroformische Lösung ist stabil und entspricht dem Beerschen Gesetz; für die Messung in l-cm-Küvetten eignen sich am besten 0,1–1 ppm Cd. Übliche Ionen stören nicht. Große Mengen einiger Kationen können mit KCN maskiert werden, wahrend [Cd(CN)₄]^2– von Formaldehyd gespalten wird. Die vorgeschlagene Methode ist eine der empfindlichsten für die Bestimmung von Cd. Die molare Extinktion des chloroformischen Extraktes betragt bei 566 nm 6,6 · 10⁴ 1 · mol^–1 · cm^–2.

     

Determination of titanium by adsorption-voltammetry with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP)

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.     

Spektralphotometrische Bestimmung von Kobalt mit 2-(5-Brom-2-pyridylazo)-5-Diethylaminophenol

Zusammenfassung Eine empfindliche und selektive spektralphotometrische Kobaltbestimmung (<0,9 g ml^–1) ist mit 2-(5-Brom-2-pyridylazo)-5-diethylaminophenol (5-Brom-PADAP) auf Grund des kinetisch stabilen Co(III)L ₂ ^– -Chelates möglich, das nach seiner Bildung bei pH 7 (Ammoniumacetat) in Gegenwart von 0,1% Triton X-100, 5,10^–3 M Ammoniumperoxodisulfat und 10% (v/v) Dimethylformamid (auch nach Zugabe von 1,25 M H₂SO₄, 1,80 M HNO₃ oder auch 0,1–0,01 M EDTA) stabil ist. Eine Reihe von 5-Brom-PADAP-Chelaten störender Ionen werden dabei zersetzt. V(V), Hg²⁺, Ni²⁺, Cu²⁺, Pd²⁺ können stören. Die Kobaltbestimmung in Cyanocobalamin und auch Trinkwasser ist auf diesem Wege möglich. Die Fehler lagen im Bereich von — 3 bis — 7 % (1,8–9 g Co/l).Herrn Prof. Dr. F. Umland, Westfälische Universität, Münster/Westfalen, sind wir für das 5-Brom-PADAP mit herzlichem Dank verpflichtet.     

Spectrophotometric determination of uranium with 1-[(5-Methyl-2-pyridyl)azo]-2-naphthol

Summary Uranium(VI) reacts with 1-[(5-methyl-2-pyridyl)azo]-2-naphthol (5-Me--PAN) in aqueous solution. The complex can be extracted with chloroform at pH 7.0–11.5 to give a red solution with an absorbance peak at 560 nm. The color is stable and the system conforms to Beer's law at the range of 1.5–8 ppm uranium in chloroform layer. Common anions and cations do not interfere. Large amounts of interfering cations can be masked by potassium cyanide, EDTA or triethanolamine. The proposed method is a selective procedure for the determination of uranium. The molar absorptivity in the chloroform extract is 2.1×10⁴ l mole^–1 cm^–1 at 560 nm.

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Zusammenfassung Uran(VI) reagiert mit 1-[(5-Methyl-2-pyridyl)azo]-2-naphthol(5-Me--PAN) in wäßriger Lösung unter Bildung einer mit Chloroform bei pH 7,0–11,5 extrahierbaren, roten Komplexverbindung mit einem Absorptionsmaximum bei 560 nm. Die Färbung ist beständig und folgt dem Beerschen Gesetz zwischen 1,5 und 8 ppm Uran. Die üblichen Ionen stören nicht. Große Mengen störender Kationen können mit Kaliumcyanid, ÄDTA oder Triäthanolamin maskiert werden. Die vorgeschlagene Methode ist für die Uranbestimmung selektiv. Die molare Extinktion des Chloroformextraktes beträgt 2,1×10⁴ l·Mol·^–1 cm^–1 bei 560 nm.

     

New derivatives of coumarin: 2-(N-R-imino)-2H-1-benzopyrans

Methods of synthesizing previously unknown derivatives of coumarin — 2-(N-R-imino)-2H-1-benzopyrans, where R = Alk, Ar — are proposed. Possibilities of alternative synthetic schemes are discussed, and hypotheses concerning probable mechanisms of the reactions are formulated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 760–766, June, 1994. Original article submitted May 23, 1994.     

Reaktion von 2-(N-Alkyl-p-hydroxyanilino)-1,4-benzochinonen Diazomethan. N-(Alkyl-p-hydroxyanilino)-4,7-indazolchinone und ihre isomeren N-Methylderivate

The reaction of N-alkyl-p-hydroxyanilinobenzoquinones1 a–d, its acetylderivatives1 ₁–c₁ and the methoxyderivative1 a₂ with diazomethan yields in dependence on the reaction-conditions the indazolquinones2 a–d, 2 a₁–c₁ or2a ₂, the1-methylindazolquinones3 a–d and3 ₁–c₁, and finally the methoxy-1-methylindazolquinones5 a–d. The 2-methyl-isomeres6 a–d are formed only in small amounts. Methylation of2 a with dimethylsulfate gives5 a and6 a in the ratio of appr 2 to 1. Acetylation of2 a–d with acetanhydride leads to the N–O-acetylderivatives, which are easily hydrolyzed to2 a₁–d₁ during work up;3 a d yields3 a₁–d₁. The structures are established by the described crossexperiments and by spectroscopy (UV/VIS, IR, NMR).

Herrn Prof. Dr.G. Zigeuner zum 60. Geburtstag gewidmet.     

Pyrroles from ketoximes and acetylene. 23. 2-(1-naphthyl)- and 2-(2-naphthyl)pyrroles and their 1-vinyl derivatives

2-(1-Naphthyl)- and 2-(2-naphthyl)pyrroles and their 1-vinyl derivatives were synthesized in 22–64% yields by the reaction of 1- and 2-acetylnaphthalene oximes with acetylene at both atmospheric pressure and elevated pressures in an alkali metal hydroxide-dimethyl sulfoxide system.See [1] for communication 22.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1351–1353, October, 1982.     

Synthesis,Structure and Properties of Some 3d-Element Complexes with 2-[2-(Hydroxybenzylidene)-amino]-2-hydoxymethylpropane-1,3-diol

2-[2-(Hydroxybenzylidene)-amino]-2-hydoxymethylpropane-1,3-diol (HL) reacts with cobalt, nickel, copper and zinc chlorides, bromides and acetates in water–ethanol solutions and gives MLX · nH₂O and ML₂ · nH₂O complexes (M = Co, Ni, Cu, Zn; X = Cl, Br; n = 0–5). Single crystals of CuLBr were grown, and its crystal structure was determined by X-ray diffraction analysis. The crystals are tetragonal, a = 17.024(2), c = 8.720(2) Å, space group P 2₁ c, Z = 8, R ₁ = 0.0349. In the structure of this complex, the copper atom coordinates the deprotonated HL molecule. The coordination polyhedron of the central atom is an elongated tetragonal pyramid. Its base is built of the imine nitrogen atom, phenolic and alcoholic oxygen atoms, and bromine atom. The apex of the pyramid is occupied by the bromine atom of the adjacent complex connected with the initial complex by the plane of sliding reflection. Thus, the crystal contains infinite chains of complexes running along the c axis, the complexes being united by both bridging bromine atoms and O–H···O hydrogen bonds. The conclusions on the compositions and structures of the remaining compounds were made on the basis of elemental and combined thermal analyses, IR spectroscopy, and magnetic chemistry data. The copper halide complexes were found to have dimeric, and the other metal complexes monomeric, structures. In the synthesized complexes, the azomethine HL can function as a bidentate or tridentate ligand. The thermolysis of the coordination compounds proceeds through the stages of elimination of crystal water molecules (75–90°C) or inner-sphere water molecules (145–155°C) and complete thermal destruction (485–550°C).     

Spectrophotometric determination of uranium(VI) with 1-(2′-thiazolylazo)-2-naphthol in the presence of Trition X-100

Uranium(VI) reacts with 1-(2-thiazolylazo)-2-naphthol to form a red-coloured chelate in the pH range 5.3–7.2, maintained by 0.04 M acetate buffer. Absorbance of the sparingly soluble complex, solubilized and stabilized by Triton X-100, is measured after 30 min and it is stable for at least 16 hours. The complex exhibits maximum absorbance at 575 and 625–630 nm, but absorbance at longer wavelengths is not stable. The 12 complex obeys Beer's law over the concentration range 0.4–6.4 g of uranium(VI) per cm³, has molar absorptivity 3.36·10⁴ dm³·mol^–1·cm^–1, Sandell sensitivity 7.0 ng·cm^–2, formation constant (log K) 9.32 and coefficient of variation ±0.77%. Effect of 60 ions has been studied and selectivity improved considerably in presence of CDTA. The method has been applied for determination of uranium content in a rock sample.     

Spectrophotometric determination of yttrium in aluminium base alloys with 1-[(5-Methyl-2-pyridyl)azo]-2-naphthol

Summary A highly sensitive and selective Spectrophotometric method has been developed for the determination of yttrium in aluminium base alloys. The method is based on the red water-insoluble complex formed when yttrium and 1-[(5-methyl-2-pyridyl)azo]-2-naphthol (5-Me--PAN) react in a pH 9.5–11.2 solution. This complex could be extracted into ether (absorption maximum, 530 nm). Beer's law is obeyed up to 1 p. p. m. of yttrium and the molar absorptivity is 6.4 · 10⁴ l · mole^–1 · cm^–1 at 530 nm.

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Zusammenfassung Eine hochempfindliche und selektive spektrophotometrische Methode zur Bestimmung von Yttrium in Aluminiumlegierungen wurde ausgearbeitet. Sie beruht auf der Bildung der roten, wasserlöslichen Komplexverbindung des Yttriums mit 1-[(5-Methyl-2-pyridyl)azo]-2-naphthol(5-Me--PAN) bei pH 9,5–11,2. Diese Verbindung läßt sich mit Äther extrahieren und hat ein Absorptionsmaximum bei 530 nm. Das Beersche Gesetz ist bis zu 1 ppm Yttrium erfüllt. Die molare Extinktion beträgt 6,4 · 10⁴ 1 · Mol^–1 cm^–1 bei 530 nm.

     

Crystal and molecular structure of 2-phenyl-2-thiono-5,6-(4′,5′-dimethylbenzo)-1,3,2-dithiaphosphepine and 2-methoxy-2-oxo-5,6-benzo-1,3,2-dioxaphosphepine

A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 5, pp. 75–80, September–October, 1990.     

Synthesis of 2-(5-halogeno-2-f uryl)-2,3-dihydroperimidines

By boiling naphthylene-1,8-diamine with 5-halogeno- and 5-nitrofurfural in benzene or xylene, 90–95% yields of the corresponding 2-(5-halogeno-2-furyl)- and 2-(5-nitro-2-furyl)-2, 3-dihydroperimidines have been obtained. The dehydrogenation of 2-(5-bromo-2-furyl)-2, 3-dihydroperimidine with palladium on carbon has given 2-(5-bromo-2-furyl)perimidine. The compounds obtained have been characterized by their UV and IR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1001–1003, July, 1973.     

Spectroscopic studies on 2-[2-(4-methylquinolin-2-yl)hydrazono]-1,2-diphenylethanone molecule and its metal complexes

The electronic absorption spectra of a hydrazone: 2-[2-(4-methylquinolin-2-yl)hydrazono]-1,2-diphenylethanone (BHQ) derived from 2-hydrazino-4-methylquinoline and 1,2-diphenylethan-1,2-dione (benzil) have been studied in various solvents of different polarities. The dependence of the band shift Δύ on the solvent parameters viz. D, Z, E_T, DN, AN, α, β and π* was discussed. Also, the effect of pH on the free hydrazone and its Co(II), Ni(II) and Cu(II) complexes was studied spectrophotometrically in 75% (v/v) dioxane–water in order to determine the dissociation and stability constants. The stoichiometry of the formed complexes was determined by three different methods: Job's, mole ratio and slope ratio which indicate the formation of 1:2, M:L complexes for Co(II) and Cu(II) and 1:1, Ni(II):L. Beer's law is valid in the range 0.32–7.04 μg/mL depending on the type of the metal ion. The use of BHQ as an indicator via a spectrophotometric titration of Cu(II) and Ni(II) with EDTA was efficient.