The detection and colorimetric determination of tin by means of substituted 1:2-dimercaptobenzenes. A specific reagent for tin

Clark, Robert E. D.

doi:10.1039/an9366100242

Cited by 45 publications

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“…In accordance with the earlier work of Hoffman (9) it was found that 2 parts of sodium carbonate to 1 part of sample are sufficient for the fusion-decomposition of most rocks and minerals. The results in Table I show that molybdenum contents from 2-gram samples of rocks fused with 4 grams of sodium carbonate compare favorably with the contents determined when 2 grams of the samples were fused with 10 grams of flux. The smaller fusion mixture facilitates ignition and dehydration procedures; and, more importantly, it excludes unnecessary reagent contaminants.…”

Section: Resultsmentioning

confidence: 81%

Molybdenum Determination of Soils and Rocks with Dithiol

Clark¹,

Axley²

1955

Anal. Chem.

127

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A simple colorimetric method is presented for the determination of submicrogram traces of molybdenum in soils and rocks. The procedure is developed on the extractable green complex formed between molybdenum and dithiol. Interference by ferric iron is eliminated by reduction with potassium iodide and sodium thiosulfate. Isoamyl acetate extracts of the molybdenum-dithiol complex are color-stable. Photometric measurements permit accurate determinations over the range of 0.02 to 10 y of molybdenum in mineral materials.OLYBDESUM frequently occurs in soils and rocks in concentrations less than 1 y per gram. The detection and estimation of these minute traces require sensitive and precise analytical procedures. Methods described in the literature either lack sensitivity or appear to yield test solutions generally susceptible to color fading and consequent uncertain precision (1 6 ) . This investigation was undertaken therefore to develop a simple colorimetric procedure of requisite color stability for the determination of molybdenum in mineral materials Substituted dimercaptobenxenes were studied by Clark ( 4 ) as precipitants for metals of the hydrogen sulfide group. He gave to the compound 4-methyl-l,2-dimercaptobenzene (toluene-3,4-dithiol) the shortened name "dithiol" and recommended its use in the determination of tin. Later Hamence (6) discovered that molybdenum formed an extractable green precipitate with dithiol, and applied this reaction in a qualitative test for trace amounts of molybdenum. IlIiller (IO, 11) studied the reactions of dithiol with molybdenum, tungsten, and rhenium. Wells and Pemberton (169, Bagshawe and Truman (f), and Short (f7) used dithiol in microchemical determinations of molybdenum in metals, Bickford, Jones, and Keene ( 2 ) employed the delicate dithiol complexes for the simultaneous estimation of molybdenum and tungsten in organic materials. After systematic evamination of reaction conditions, Piper and Becknith ( I S ) presented a dithiol method for the determination of small amounts of molybdenum in plants. The foregoing applications suggested the suitability of this reagent for the determination of molybdenum in mineral materials.Soils and rocks, however, were found to possess constituents in concentrations sufficient to prevent the normal reaction between molybdenum and dithiol. Procedures were introduced to control interferences from silica, platinum, iron, tungsten, and copper. The modified method was then applied successfully to the determination of microgram quantities of molybdenuni in a wide variety of inorganic materials. REAGENTS Water. Dithiol, 0.2%. Redistill in an all-borosilicate glass apparatus Dissolve a 1 gram v d of dithiol in 500 ml. of 1 yo sodium hydroxide solution. Stir the mixture occasionally during a period of 1 hour. Add thioglycolic acid (about 8 ml.) dropwise until a faint permanent opalescent turbidity begins to form. Transfer to 4-ounce narrow-mouthed bottles fitted with plastic screw caps. Store the reagent solution in a refrigerator a t 5" C. a t all ti...

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Section: Resultsmentioning

confidence: 81%

Molybdenum Determination of Soils and Rocks with Dithiol

Clark¹,

Axley²

1955

Anal. Chem.

127

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“…Research into the coordination chemistry with dithiolene ligands started in the 1930s with toluene-3,4-dithiol and 1-chlorobenzene-3,4-dithiol [154][155][156]. A milestone was the discovery of dithiolenes' non-innocent character and its impact on the electronic properties of the coordinated metal centers in the 1960s (see Figure 1 above), which was first noted for nickel bis(dithiolene) complexes [3,[157][158][159][160].…”

Section: Functional Dithiolene-bearing Analogues With Atypical/non-na...mentioning

confidence: 99%

Inspired by Nature—Functional Analogues of Molybdenum and Tungsten-Dependent Oxidoreductases

et al. 2022

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Throughout the previous ten years many scientists took inspiration from natural molybdenum and tungsten-dependent oxidoreductases to build functional active site analogues. These studies not only led to an ever more detailed mechanistic understanding of the biological template, but also paved the way to atypical selectivity and activity, such as catalytic hydrogen evolution. This review is aimed at representing the last decade’s progress in the research of and with molybdenum and tungsten functional model compounds. The portrayed systems, organized according to their ability to facilitate typical and artificial enzyme reactions, comprise complexes with non-innocent dithiolene ligands, resembling molybdopterin, as well as entirely non-natural nitrogen, oxygen, and/or sulfur bearing chelating donor ligands. All model compounds receive individual attention, highlighting the specific novelty that each provides for our understanding of the enzymatic mechanisms, such as oxygen atom transfer and proton-coupled electron transfer, or that each presents for exploiting new and useful catalytic capability. Overall, a shift in the application of these model compounds towards uncommon reactions is noted, the latter are comprehensively discussed.

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“…~H SH Sn (II) gibt mit Dithiol (Toluol-3,4-dithiol; 1-Methyl-3,4-di-mercaptobenzol) in saurer Lösung beim Erwärmen eine rote, kolloidale Fällung [63,64]. Eine Reaktion mit Sn (IV) erscheint verzögert und weniger empfindlich; wahrscheinlich erfolgt die Reaktion erst nach Reduktion zu Sn (II) vollständig.…”

Section: Ch3unclassified

“…In analoger Weise reagiert Sn mit 1-Chlor-3,4-dimercaptobenzol [63], doch soll das Reagens gegen Oxydation noch empfindlicher als Dithiol sein.…”

Section: Ch3unclassified

Sn — Zinn

Koch¹,

Koch-Dedic²

1974

Handbuch Der Spurenanalyse

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Tabelle 171. Empfindlichkeit 511 und Bestimmungsgrenze L 0 der Verfahren Verfahren Brenzcatechinviolett BrenzcatechinviolettfCetyltrimethylammoniumbromid Dithiol Phenylfluoron 3'-Pyridylfluoron (pH 2) ILg Sn • m1-1 • cm-1 0,0017--0,0018 (552-555 nm) 0,00125 (662 nm) 0,020 (530 nm) 0,0016 (510 nm, pH-2,6); 0,0021--0,0036 (510-530 nm, pH-3,8) -0,0012 (546 nm) A. Trennungen 0,043-0,046 (552-555 nm) 0,031 (662 nm) 0,50 (530 nm) 0,038 (510 nm, pH-2,6); 0,05-0,09 (510-530 nm, pH-3,8) -0,030 (546 nm) Sn (II) und Sn (IV) lassen sich aus halogenwasserstoffsauren Lösungen unter bestimmten Bedingungen durch verschiedene organische Lösungsmittel mitunter quantitativ extrahieren (s. S. 259ff.). Über die Extraktion von Sni 4 aus NaiJHClOJNaClO,-Lösung mit Benzol [1] s. S. 1136. Sn(IV) wurde aus 9n H 2 SOJ0,5m KI-Lösung mit Toluol [1 a], bzw. aus ,.., 4,4m HClOJ-Im H 2 S0 4 / -2m Nai-Lösung mit Benzol [1 b] quantitativ extrahiert und aus der Toluolphase mit,.., O,In NaOH rückgeschüttelt[1 a]. Aus 4-6n HI-Lösung läßt sich Sn(IV) mit Benzol selektiv extrahieren, während In und Sb (III) in der wäßrigen Phase verbleiben, aus der danach bei 4n HI mit Diisopropyläther In selektiv extrahiert werden kann [2]. Sn(IV) und Sb(V) lassen sich durch selektive Extraktion des letzteren aus 7n HCl mit Isoamylacetat trennen . .Sn(IV) kann mit Tri-n-octylphosphonoxyd(TOPO)/Cyclohexan oder noch besser mit Tris(2-äthylhexyl)phosphinoxyd(TÄPO)JCyclohexan aus HC1/H 2 S04-Lösung quantitativ extrahiert werden [3]. Im letztgenannten Fall wird der extrahierten Verbindung die Formel SnC1 4 • 2 TÄPO zugeordnet. Für eine optimale Extraktion ist die herrschende Konzentration an HCl, H 2 S0 4 und TÄPO maßgebend; sie ist am günstigsten aus Im HC1J2m H 2 S0 4 -Lösung mit O,Oim TÄPOJCyclohexan. Unter diesen Bedingungen werden vorwiegend Sb, in geringerem Ausmaß Ga, Fe und Mo mitextrahiert. HN0 3 stört stark. Das Verfahren wurde zur Sn-Isolierung bei der photometrischen Bestimmung mit Brenzcatechinviolett in Blei-, Zink-, Kupfer-, Eisen-und Zirkoniumlegierungen herangezogen [3], wobei die eben erwähnten Störelemente aus dem TÄPO-Extrakt mit Im HClf2m H 2 S0 4 teilweise rückgeschüttelt wurden. I-5 g Fe wurden durch Extraktion (E% = 99) mit 2,5m TBPJBenzol aus I0,5n HCI-Lösung von I-250 !Lg Sn(IV) abgetrennt [1 b]. Mit Dibutylphosphorsäurefn-Butyläther kann Sn(IV) aus ln HN0 3 -Lösung in Anwesenheit von 3% H 2 0 2 zu >95% extrahiert werden [4]. Mit Sn werden In, Y und Zr quantitativ, Nb und Ta zu größerem, Mo zu geringerem Teil und Ag, As, Cd, Ce, Ge, La, Pd, Rh, Ru, Sb, Se, Sr und Te zu < 5% extrahiert. O. G. Koch et al., Handbuch der Spurenanalyse © Springer-Verlag Berlin Heidelberg 1974 Die Bestimmung einzelner Elemente Lit. S. 1142 Aus-0,5n HCl/-0,15n KSCN-Lösung wurde Sn(II) oder Sn(IV) durch dreimaliges Ausschütteln mit Äthylacetat als Thiocyanat extrahiert, während die Hauptmenge des anwesenden Fe durch Reduzieren mit Ascorbinsäure in der wäßrigen Phase verbleibt [ 5].Sn (II) läßt sich mit AmmoniumdiäthyldithiocarbamatfCHC1 3 aus H 2 S0 4 (1 + 9) ausschüttel...

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The detection and colorimetric determination of tin by means of substituted 1:2-dimercaptobenzenes. A specific reagent for tin

Cited by 45 publications

References 0 publications

Molybdenum Determination of Soils and Rocks with Dithiol

Molybdenum Determination of Soils and Rocks with Dithiol

Inspired by Nature—Functional Analogues of Molybdenum and Tungsten-Dependent Oxidoreductases

Sn — Zinn

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