Extraction and spectrophotometric determination of titanium(IV) withN 1-hydroxy-N 1,N 2-diphenylbenzamidine and thiocyanate

A precise, reliable, sensitive, and selective method for the determination of titanium(IV) is described. Titanium(IV) reacts withN ¹-hydroxy-N ¹,N ²-diphenylbenzamidine (HDPBA) and thiocyanate to form an orange-coloured mixed-ligand complex of stoichiometry 112 (Ti SCN^– HDPBA). The complex is quantitatively extractable into toluene from 0.05–0.15M hydrochloric acid. The spectrum of the complex exhibits an absorption maximum at 400 nm with a molar absorptivity of 20000M ^–1 cm^–1 and the coloured system obeys Beer's law in the concentration range 0.20–3.0 gml^–1 titanium. The effects of foreign ions and of various experimental parameters have been studied to establish the optimum conditions for the extraction and determination of titanium. The precision of the method has been evaluated and the relative standard deviation has been found to be 0.53%. The method has been successfully applied to the determination of titanium in synthetic matrices corresponding to titanium-containing ores, minerals, and alloys.     

Extraction-spectrophotometric determination of iron with 2-(2′-benzothiazolylazo)-4,6-dimethylphenol

An extraction-spectrophotometric method for the determination of trace amounts of iron based on its extraction into chloroform with 2-(2-benzothiazolylazo)-4,6-dimethylphenol (BTADMP) from a pH 6.5 medium has been developed. The extracted 12 FeBTADMP complex species allow the determination of 4–30gmg of iron (=3.92×10⁴1·mol^–1·cm^–1 at 790 nm). The method is highly selective and has been applied to the determination of iron in polymineral-polyvitamin pharmaceutical products.     

Synthesis to spectroscopy of titanium(IV) and zirconium(IV) chelates with biologically active ON donor systems

Summary A new class of 16 organotitanium(IV) and organozirconium(IV) chelates with biologically active monofunctional bidentate semicarbazones having the ON donor system were prepared by reacting 11 and 12 stoichiometric proportions of bis(cyclopentadienyl)titanium(IV) dichloride and bis(cyclopentadienyl)zirconium(IV) dichloride with the appropriate ligand, prepared by condensing heterocyclic ketones and semicarbazide hydrochlorides in presence of NaOAc. Trigonal bipyramidal and octahedral structures have been suggested for the 11 and 12 (ML) complexes of titanium(IV) and zirconium(IV), respectively, on the basis of spectral analyses.     

Spectrophotometric determination of vanadium with 4-(1′H-1′,2′,4′-Triazolyl-3′-azo)-2-methylresorcinol

Summary 4-(1H-1,2,4-Triazolyl-3-azo)-2-methylresorcinol reacts with vanadium(V) at pH 8.10 (Tris-HClO₄ buffer solution) to produce a pink-violet 11 complex ( _max=525 nm,=2.55×10⁴l·mol^–1· cm^–1) in a 50% (v/v) methanol-water medium, which allows the spectrophotometric determination of 0.1 to 1.51 ppm of vanadium. The method has been applied for the determination of the vanadium content in low alloy steels.

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Spectrophotometriscbe Bestimmung von Vanadin mit 4-(1H-1,2,4-triazo-lyl-3-azo)-2-methylresorcin

Zusammenfassung Vanadin bildet bei pH 8,10 (Tris-HClO₄-buffer) mit 4-(1H-1,2,4-tri-azolyl-3-azo)-2-methylresorcin ein rosenrot-violettes Chelat, dessen Absorptionsmaximum bei 525 nm in Gegenwart von 50% Methylalkohol gemessen wird. Dieser 11-Komplex entspricht bei einer Vanadin-Konzentration von 0,1–1,51g/ml dem Beerschen Gesetz; seine molare Absorptivität ist 2,55×10⁴l·mol^–1·cm^–1. Das Verfahren wurde zur Bestimmung des Vanadins in Stahl verwendet.

     

4(5)-D-Arabinotetrahydroxybutylimidazoline-2-thione (THBIT), a new reagent for the spectrophotometric determination of palladium

Summary 4(5)-D-Arabinotetrahydroxybutylimidazoline-2-thione, THBIT, is proposed as a new reagent for the spectrophotometric determination of Pd(II). Pd(II) forms 11, 12 and 14 complexes with THBIT. The system conforms to Beer's law up to 5g/ml palladium concentration in aqueous medium (molar absorptivity, 1.99×10⁴ l· mole^–1·cm^–1 at 338 nm). The most serious interference is from Hg(II), Os(VIII), Ru(IV), Cr(VI), V(V) and S₂O₃ ^2–. The method has been used successfully for the determination of palladium in catalysts and synthetic samples.     

Interaction of tin (IV) chloride with sulfolane and between tin (IV) chloride and lithium chloride in sulfolane solution

Tin (IV) chloride reacts with sulfolane (S) to form a cis-octahedral adduct SnCl₄·S₂. Solutions of lithium chloride and tin (IV) chloride in sulfolane contain the complex ions SnCl ₅ ^– and SnCl ₆ ^2– at 11 and 21 mole ratios of constituents, respectively. The complexes are characterized by conductimetry and by Mössbauer, IR, and Raman spectroscopy.     

Spectrophotometric study on the quaternary complex of titanium (IV) with secondary ligands, 2,6,7-trihydroxylphenyl-fluorone derivatives and cetyltrimethylammonium bromide

The new color reactions of titanium (IV) with six 2,6,7-trihydroxyl-9-phenylsubstituted-3-fluorone derivatives (THPF) have been studied in the presence of nitrilotriacetic acid (NTA) and cetyltrimethylammonium bromide (CTMAB). The effects of secondary ligands such as NTA, ascorbic acid, hydroxylamine and mandelic acid on the ternary complex of titanium (IV) have been reported. It was found that the system of titanium (IV)-2,6,7-trihydroxyl-9-(2,4-dichlorophenyl)-3-fluorone (DCPF)-NTA-CTMAB quaternary complex is the most sensitive in these systems studied. The apparent molar absorptivity of the complex at 576 nm is 1.9 × 10⁵ 1·mol^–1·cm^–1. The stoichiometric ratio of the Ti (IV)-NTA-DCPF-CTMAB complex is estimated to be 1 1 3 3. The proposed method proves to be satisfactory for the direct determination of titanium in alloy steels, silicate minerals and aluminium alloys. The method is highly sensitive and selective.     

Spectrophotometric determination of Fe(III) with tiron in the presence of cationic surfactant and its application for the determination of iron in Al-alloys and Cu-based alloys

A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5.6 is reported. The complex is extracted into a chloroform-propan-2-ol (41) mixture and shows maximum absorbance at 520 nm. Beer's law is obeyed in the range 1–14 g/ml with an average molar absorptivity of 15800 l mol^–1 cm^–1. The molar ratio as determined by Job's method for Fe:tiron:CPC is 143. Interferences by various ions are examined. Zr, Ti and Mo interfere heavily. The method is applied for the determination of iron in Al-based and Cu-based alloys, using appropriate masking agents.     

Simultaneous determination of iron(III) and cobalt(II) withN-phenylcinnamohydroxamic acid and thiocyanate by extraction and spectrophotometry

Simple, precise, sensitive, and highly selective methods for the separate determination of iron(III) and cobalt(II) and for the simultaneous determination of both metal ions are described. Iron(III) and cobalt(II) react with thiocyanate in the presence ofN-phenylcinnamohydroxamic acid (PCHA) to form pinkish red and blue coloured complexes, respectively. Both the iron(III) and cobalt(II) complexes having stoichiometric composition of 122 (FeSCN^–PCHA) and 14 (CoSCN^–), respectively, are quantitatively extractable into ethylacetate from 0.5–1.5 M hydrochloric acid solutions. The spectra of iron(III) and cobalt(II) complexes in the visible region exhibit absorption maxima at 495 and 625 nm, respectively. The coloured systems obey Beer's law in the concentration range of 0.2–4.0g/ml of iron and 2–40g/ml of cobalt. The effects of foreign ions and of various experimental parameters were studied to establish the optimum conditions for the extraction and determination of iron and cobalt. The methods have been applied successfully to the analysis of blood, vitamin B₁₂, and standard steels for iron and cobalt.     

Komplexbildung im System Ni2+—o-Methylbenzamidoxim

Zusammenfassung Die Komplexe des Ni²⁺ mit o-Methylbenzamidoxim wurden in neutraler und in alkalischer Lösung spektrophotometrisch untersucht. Die Bildungskonstanten sindK ₁=40 für 11 undK ₂=1,7·10² für 12 in neutraler Lösung und ₁ = =(3,92 ±0,2) · 10⁴für 11 und lgK = lg ₁ + lg ₂ = 3,45 ± ±0,15 für 12 bei 25° und =1 in alkalischer Lösung.

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Complex formation in the systemeNi ²⁺—o-methylbenzamide oxime

The complexes of Ni²⁺ with o-methylbenzamide oxime were investigated spectrophotometrically in neutral as well as in alkaline solution. The formation constants areK ₁=40 for 11 andK ₂=1.7·10² for 12 in the neutral solution and ₁ = =(3.92 ±0.2) · 10⁴ for 11 and lgK = lg ₁ + lg ₂ = 3.45 ± ±0.15 for 12 at 25° and =1 for the alkaline solution. *** DIRECT SUPPORT *** A3615139 00007

     

Phthalocyaninartige Bor-Komplexe

Zusammenfassung Aus Halogenboranen und Organohalogenboranen (RBX ₂R=C₆H₅, Cl, Br;X=F, Cl, Br) sowie aus Organoboranen oder Thioboranen entstehen mit Phthalodinitril Triisoindolo-[1,2,3-cd1,2,3-gh1,2,3-kl][2,3a,5,6a,8,9a,9b]-hexaazaboraphenalene von denen die B–Cl- und B–F-Verbindungen näher charakterisiert werden.Dekaboran(14), Diboran(6) oder Boranaddukte von Stickstoffbasen liefern hingegen mit Phthalodinitril metallfreies Phthalocyanin.

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Triisoindolo[1,2,3-cd1,2,3-gh1,2,3-kl][2,3a,5,6a,8,9a,9b]-hexa-azaboraphenalene

Triisoindolo[1,2,3-cd1,2,3-gh1,2,3-kl][2,3a,5,6a,8, 9a,9b]-hexaazaboraphenalenes are obtained from the reactions of haloboranes and organohaloboranes (RBX ₂R=C₆H₅, Cl, Br;X=F, Cl, Br) as well as from organoboranes or thioboranes with phthalodinitrile. The B–Cl and B–F compound have been characterized by analyses, i.r.-, u.v.- and mass-spectrometry.Diborane(6), dekaborane(14) and amine-boranes, however, upon reaction with phthalodinitrile lead to high yields of metal free phthalocyanine.

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Herrn Prof. Dr.M. Pailer zum 60. Geburtstag gewidmet.     

Selective and sensitive extraction spectrophotometric method for the determination of vanadium (V) as a mixed ligand complex withN-phenyl benzohydroxamic acid and 4-(2-pyridylazo)resorcinol in non-aqueous media

A selective, sensitive and direct method for the spectrophotometric determination of vanadium in steels is developed in which vanadium is extracted withN-phenyl benzohydroxamic acid (PBHA) into chloroform from 5M hydrochloric acid medium followed by colour development by addition of 4-(2-pyridylazo)resorcinol (PAR) inN,N-dimethyl formamide (DMF). The vanadium(V)-PBHA-PAR mixed ligand complex shows maximum absorbance at 560 nm with a molar absorptivity 3.6 × 10⁴ l mol^–1 cm^–1 and obeys Beer's law up to 2.0 g/ml of vanadium. The composition of the mixed ligand complex is determined by Job's method of continuous variations which revealed a 1 1 1 ratio for V(V) PBHA PAR. This method can be directly applied for the determination of vanadium in steels, while in the case of titanium base alloys, after separation of titanium matrix it gives good results even at 50–200 g of vanadium per gram level.     

Zur colorimetrischen Bestimmung von Cer(IV) bei Anwesenheit von Eisen(III) und Lanthan(III) mittels Orthodianisidin

Zusammenfassung Es wird eine neue colorimetrische Methode zur Bestimmung von Cer(IV) unter Anwendung von Orthodianisidin als Reagens vorgeschlagen, mit der Cer(IV)-konzentrationen zwischen 0,86 und 10,39g/ml erfaßt werden können. Unter Anwendung von Phosphorsäure als Maskierungsmittel ermöglicht diese Methode die colorimetrische Bestimmung von Cer(IV) im Beisein von Eisen(III) bis zum Verhältnis Ce^IVFe^III=1800. Desgleichen läßt die Methode die colorimetrische Bestimmung von Cer(IV) bei Anwesenheit von Lanthan(III) bis zum Verhältnis Ce^IVLa^III=150 zu.     

Nephelometric determination of germanium(IV) witho-phenanthroline and bromopyrogallol red in the presence of triton X-100

The light scattering of germanium(IV) witho-phenanthroline [phen] and bromopyrogallol red [BPR] in the presence of Triton X-100 has been studied. The ternary complex shows a constant light scattering intensity in an acidic medium (0.02 mol/l HCl+0.02 mol/l H₃PO₄). The maximum wavelength was 332 nm. The calibration graph is linear in the range 0.03–10 g/25 ml for Ge(IV). The detection limit is 0.03 g/25 ml. The composition of the ternary complex is GephenBPR = 122. The effects of diverse ions on the determination of Ge(IV) were examined. This simple method with high sensitivity can be successfully applied to the determination of Ge(IV) in coal fly ash, with a relative standard deviation of 2%.     

Extraction spectrophotometric investigation of mixed ligand complex of molybdenum(V) with thiocyanate and 4-acetyl-2-(acetylamino)-5-dimethyl-Δ2-1,3,4-thiadiazole

A sensitive spectrophotometric method is developed for the determination of small amounts of molybdenum based on the extraction of molybdenum-thiocyanate-4-acetyl-2-(acetylamino)-5-dimethyl- ²-1,3,4-thiadiazole complex into chloroform from hydrochloric acid medium which is orange red in colour. The complex has an absorption maximum at 470 nm with a molar absorptivity of 2.01×10⁴l·mole^–1·cm^–1. Beer's law is valid over the concentration range 0.06–2.5 ppm of molybdenum with an optimum concentration range of 0.15–2.2 ppm. The ternary complex is stable for over one week at room temperature. Equilibrium shift method indicates 142 composition for molybdenum-thio-cyanate-4-acetyl-2-(acetylamino)-5-dimethyl- ²-1,3,4-thiadiazole complex. The effects of acidity, reagent concentrations, time, temperature and diverse ions upon the absorbance of the complex are critically assessed. This method has been used successfully for the determination of molybdenum in molybdenum steels.     

Spectrophotometric determination of palladium with a new chelating reagent,N,N-dimethyl-N′-(4-methyl-5-nitro-2-thiazolyl) thiourea

Summary N,N-Ditnethyl-N-(4-methyl-5-nitro-2-thiazolyl)thiourea A new spectrophotometric method for the determination of palladium with N,N-dimethyl-N-(4-methyl-5-nitro-2-thiazolyl)thiourea (DMNT) is proposed. DMNT instantly forms a yellow chelate with Pd(II) at pH 2 at room temperature, which is readily extracted into organic solvents such as chloroform and shows a higher absorption maximum (=40,400) at 413 nm. The ratio of Pd(II) to reagent in the chelate is 12 as determined by the widely used method and also verified by synthesis of the authentic Pd-chelate. The chelate conforms well with the Lambert-Beer's law over a wide concentration range (3.3–22g in 10 ml chloroform). The optimum concentration range of palladium for spectrophotometry by the Ringbom plot is 5.6–18.6g in 10 ml of chloroform solution. This method gives a good reproducibility, high sensitivity and high accuracy in the presence of many foreign ions.

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Spektrophotometrische Bestimmung von Palladium mit N,N-Dimethyl-N- (4-methyl-5-nitro-2-thiazolyl)-thioharnstoff (DMNT)

Zusammenfassung Eine neue spektrophotometrische Methode zur Bestimmung von Palladium mit DMNT wurde vorgeschlagen. Dieses Reagens bildet mit Pd(II) bei pH 2 und Zimmertemperatur ein gelbes Chelat, das mit Chloroform gut extrahierbar ist und bei 413 nm ein hohes Absorptionsmaximum (=40400) zeigt. Dessen Zusammensetzung wurde in üblicher Weise zu 12=Pd: DMNT bestimmt. Im Konzentrationsbereich 3,3–22g/10 ml entspricht das Chelat dem Lambert-Beerschen Gesetz. Die optimale Konzentration für die spektrophotometrische Bestimmung liegt zwischen 5,6 und 18,6g/10 ml Chloroform. Das Verfahren gibt gut reproduzierbare Ergebnisse, ist hoch empfindlich und auch in Anwesenheit vieler Fremdionen sehr genau.

     

Study of Cr(VI)-2-oximinodimedone dithiosemicarbazone reaction and simultaneous determination of Cr(VI) and Fe(III)

Summary 2-Oximinodimedone dithiosemicarbazone reacts with Cr(VI) in strongly acid medium. The orange colour obtained has been used to propose a spectrophotometric method of Cr(VI) determination in the concentration range 0.40–9.5g ml^–1 (=5600 mole^–1-cm^–1 at 485 nm). The stoichiometry of the reaction is 32 (reagentCr(VI)) which is in accordance with the oxidation reaction of the reagent by Cr(VI). The method has been applied to the determination of Cr(VI) and Fe(III) in ceramic materials.

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Eine Studie zur Cr(VI)-2-oximinodimedondithiosemicarbazon-Reaktion und die simultane Bestimmung von Cr(VI) und Fe(III)

Zusammenfassung 2-Oximinodimedonedithiosemicarbazon reagiert in stark saurem Milieu mit Cr(VI). Die orange Farbe kann im Konzentrationsbereich von 0.4–9,5g/ml zur spektrophotometrischen Cr(VI)-Bestimmung verwendet werden (=5600 1 mol^–1cm^–1bei 485 nm). Die Stöchiometrie der Reaktion ist 32 (Reagens: Cr(VI)) und entspricht der Oxidation des Reagens durch Cr(VI). Die Methode wurde zur Bestimmung von Cr(VI) und Fe(III) in keramischen Materialien eingesetzt.

     

Some effective solvents for rapid and reliable characterization of phenylthiohydantoin-amino acids

Summary One-dimensional chromatography with internal standards permits reliable identification of the phenylthiohydantoins from all the common amino acids with the following TLC systems: silica gel — chloroform/n-butyl acetate (9010), di-isopropylether/ethanol (955), dichloromethane/ethanol/acetic acid (9082) ortrans-dichloroethylene/ethanol/acetic acid (88102); and cellulose with 25% formic acid — heptane/isobutanol/75% fromic acid (40309) or silica gel — chloroform/ ethanol/acetic acid/water (50470.52.5).Abbreviations: PTH=phenylthiohydantoin, TLC=thin-layer chromatography, HPTLC=high-performance TLC; other abbreviations: see end of text. Proportions in solvent mixtures are v/v except where otherwise indicated.