Tetrakis(pyridine)silver(II) peroxydisulfate

Last updated
Tetrakis(pyridine)silver(II) peroxydisulfate
Structure of Tetrakis(pyridine)silver(II) peroxydisulfate.png
Sample of Tetrakis(pyridine)silver(II) peroxydisulfate.jpg
Names
Other names
Tetrakis(pyridine)silver(II) persulfate, Tetrakis(pyridine)silver(II) peroxodisulfate
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/4C5H5N.Ag.H2O8S2/c4*1-2-4-6-5-3-1;;1-9(2,3)7-8-10(4,5)6/h4*1-5H;;(H,1,2,3)(H,4,5,6)/q;;;;+2;/p-2
    Key: LPADOLSGWNTMHL-UHFFFAOYSA-L
  • [Ag].[O-]S(=O)(=O)OOS([O-])(=O)=O.n1ccccc1.n1ccccc1.n1ccccc1.n1ccccc1
Properties
C20H20N4AgS2O8
Molar mass 616.39 g·mol−1
Appearanceorange solid
insoluble
Structure
Square planar
Hazards
Flash point 20 °C (68 °F; 293 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Tetrakis(pyridine)silver(II) peroxydisulfate is a chemical compound which contains silver in the rare oxidation state of +2.

Contents

Preparation

The salt can be easily prepared by oxidizing a soluble silver salt with excess potassium peroxydisulfate in aqueous pyridine solution, where upon the product precipitates out almost quantitatively. [1]

2 AgNO3 + 8 C5H5N + 3 K2S2O8 → 2 [Ag(C5H5N)4]S2O8 + 2 K2SO4 + 2 KNO3

Structure

Since the Ag2+ ion has a d9 configuration, the salt is paramagnetic. [1]

Properties

The compound is in the form of non-hygroscopic orange granulate. It is stable in the air for several days when stored away from light, and is stable up to several months if dried in vacuo over potassium hydroxide, decomposing into a white paste. Its stability can be attributed to its insolubility in both polar and non-polar solvents.

The compound decomposes at 137 °C. It dissolves in concentrated nitric acid without reduction, and is converted to the black silver(I,III) oxide in aqueous sodium hydroxide solution. [1]

It is a powerful oxidizing agent, and is illustrated by the fact that it oxidizes Mn2+ ions to permanganates. When the pyridine ligands were removed, the transient square planar [Ag(H2O)4]2+ remains, which spontaneously oxidizes water to oxygen. [2]

Ag2+ + e Ag+ {E° = +1.980 V}

Applications in organic chemistry

The complex ion can easily oxidize alcohol, aldehyde and amine, and capable of decarboxylating α-hydroxycarboxylic acids and phenylacetic acids to give the corresponding carbonyl compounds. [3] Benzylic C-H bonds are oxidatively converted to carbonyl groups: [3]

Oxidation of dibenzyl ether and thioether to the corresponding ester and thioester by TSPP.png

Aromatic thiols and allylaryl thioethers are oxidized to arylsulfonic acids, which gives an alternative route to produce arylsulfonic acids with mild conditions. [3]

Safety

As the compound contains the peroxydisulfate ion as the counter anion, this compound should be treated as an explosive even though its explosive properties were not well established. The complex also releases tiny amounts of pyridine vapor which is a possible carcinogen.

Related Research Articles

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to an organyl group, or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Aldehyde</span> Organic compound containing the functional group R−CH=O

In organic chemistry, an aldehyde is an organic compound containing a functional group with the structure R−CH=O. The functional group itself can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are a common motif in many chemicals important in technology and biology.

<span class="mw-page-title-main">Potassium hydroxide</span> Inorganic compound (KOH)

Potassium hydroxide is an inorganic compound with the formula KOH, and is commonly called caustic potash.

<span class="mw-page-title-main">Fehling's solution</span> Chemical test for the reducibility of a sugar

In organic chemistry, Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reagent test. The test was developed by German chemist Hermann von Fehling in 1849.

<span class="mw-page-title-main">Chromate and dichromate</span> Chromium(VI) anions

Chromate salts contain the chromate anion, CrO2−
4
. Dichromate salts contain the dichromate anion, Cr
2
O2−
7
. They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible.

<span class="mw-page-title-main">Potassium ferrate</span> Chemical compound

Potassium ferrate is an inorganic compound with the formula K2FeO4. It is the potassium salt of ferric acid. Potassium ferrate is a powerful oxidizing agent with applications in green chemistry, organic synthesis, and cathode technology.

<span class="mw-page-title-main">Tollens' reagent</span> Chemical reagent used to distinguish between aldehydes and ketones

Tollens' reagent is a chemical reagent used to distinguish between aldehydes and ketones along with some alpha-hydroxy ketones which can tautomerize into aldehydes. The reagent consists of a solution of silver nitrate, ammonium hydroxide and some sodium hydroxide. It was named after its discoverer, the German chemist Bernhard Tollens. A positive test with Tollens' reagent is indicated by the precipitation of elemental silver, often producing a characteristic "silver mirror" on the inner surface of the reaction vessel.

<span class="mw-page-title-main">Copper(II) chloride</span> Chemical compound

Copper(II) chloride, also known as cupric chloride, is an inorganic compound with the chemical formula CuCl2. The monoclinic yellowish-brown anhydrous form slowly absorbs moisture to form the orthorhombic blue-green dihydrate CuCl2·2H2O, with two water molecules of hydration. It is industrially produced for use as a co-catalyst in the Wacker process.

<span class="mw-page-title-main">Pyridinium chlorochromate</span> Chemical compound

Pyridinium chlorochromate (PCC) is a yellow-orange salt with the formula [C5H5NH]+[CrO3Cl]. It is a reagent in organic synthesis used primarily for oxidation of alcohols to form carbonyls. A variety of related compounds are known with similar reactivity. PCC offers the advantage of the selective oxidation of alcohols to aldehydes or ketones, whereas many other reagents are less selective.

<span class="mw-page-title-main">Ferrate(VI)</span> Ion

Ferrate(VI) is the inorganic anion with the chemical formula [FeO4]2−. It is photosensitive, contributes a pale violet colour to compounds and solutions containing it and is one of the strongest water-stable oxidizing species known. Although it is classified as a weak base, concentrated solutions containing ferrate(VI) are corrosive and attack the skin and are only stable at high pH. It is similar to the somewhat more stable permanganate.

<span class="mw-page-title-main">Silver oxide</span> Chemical compound

Silver oxide is the chemical compound with the formula Ag2O. It is a fine black or dark brown powder that is used to prepare other silver compounds.

Ruthenium compounds are compounds containing the element ruthenium (Ru). Ruthenium compounds can have oxidation states ranging from 0 to +8, and −2. The properties of ruthenium and osmium compounds are often similar. The +2, +3, and +4 states are the most common. The most prevalent precursor is ruthenium trichloride, a red solid that is poorly defined chemically but versatile synthetically.

<span class="mw-page-title-main">Silver compounds</span> Chemical compounds containing silver

Silver is a relatively unreactive metal, although it can form several compounds. The common oxidation states of silver are (in order of commonness): +1 (the most stable state; for example, silver nitrate, AgNO3); +2 (highly oxidising; for example, silver(II) fluoride, AgF2); and even very rarely +3 (extreme oxidising; for example, potassium tetrafluoroargentate(III), KAgF4). The +3 state requires very strong oxidising agents to attain, such as fluorine or peroxodisulfate, and some silver(III) compounds react with atmospheric moisture and attack glass. Indeed, silver(III) fluoride is usually obtained by reacting silver or silver monofluoride with the strongest known oxidizing agent, krypton difluoride.

Iron shows the characteristic chemical properties of the transition metals, namely the ability to form variable oxidation states differing by steps of one and a very large coordination and organometallic chemistry: indeed, it was the discovery of an iron compound, ferrocene, that revolutionalized the latter field in the 1950s. Iron is sometimes considered as a prototype for the entire block of transition metals, due to its abundance and the immense role it has played in the technological progress of humanity. Its 26 electrons are arranged in the configuration [Ar]3d64s2, of which the 3d and 4s electrons are relatively close in energy, and thus it can lose a variable number of electrons and there is no clear point where further ionization becomes unprofitable.

<span class="mw-page-title-main">Peroxydisulfate</span> Ion containing sulfur and oxygen with a charge of 2-

The peroxydisulfate ion, S
2
O2−
8
, is an oxyanion, the anion of peroxydisulfuric acid. It is commonly referred to as persulfate, but this term also refers to the peroxomonosulfate ion, SO2−
5
. It is also called peroxodisulfate. Approximately 500,000 tons of salts containing this anion are produced annually. Important salts include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8). These salts are colourless, water-soluble solids that are strong oxidants.

<span class="mw-page-title-main">Thiocyanogen</span> Chemical compound

Thiocyanogen, (SCN)2, is a pseudohalogen derived from the pseudohalide thiocyanate, [SCN], with behavior intermediate between dibromine and diiodine. This hexatomic compound exhibits C2 point group symmetry and has the connectivity NCS-SCN.

Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids.

<span class="mw-page-title-main">Chromium(VI) oxide peroxide</span> Chemical compound

Chromium(VI) oxide peroxide is the name given to a collection of chromium coordination complexes. They have the formula CrO(O2)2L where L is a ligand. These species are dark blue and often labile. They all feature oxo ligand and two peroxo ligands, with the remaining coordination sites occupied by water, hydroxide, ether, or other Lewis bases.

<span class="mw-page-title-main">Silver dichromate</span> Chemical compound

Silver dichromate is a chemical compound with the formula Ag2Cr2O7. It is insoluble in water and decomposes when treated with hot water. Its anion has a charge of -2.

<span class="mw-page-title-main">Transition metal pyridine complexes</span>

Transition metal pyridine complexes encompass many coordination complexes that contain pyridine as a ligand. Most examples are mixed-ligand complexes. Many variants of pyridine are also known to coordinate to metal ions, such as the methylpyridines, quinolines, and more complex rings.

References

  1. 1 2 3 Kauffman, George B.; Houghten, Richard A.; Likins, Robert E.; Posson, Philip L.; Ray, R. K.; Fackler, John P.; Theron Stubbs, R. (1998-01-01). Darensbourg, rcetta Y. (ed.). Tetrakis(Pyridine)Silver(2+)Peroxydisulfate. John Wiley & Sons, Inc. pp. 177–181. doi:10.1002/9780470132630.ch30. ISBN   9780470132630.
  2. Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3rd ed.). Prentice Hall. p. 797. ISBN   978-0-13-175553-6.
  3. 1 2 3 Habib Firouzabadi, Peyman Salehi, Iraj Mohammadpour-Baltork. "Tetrakis(pyridine)silver(II) Peroxodisulfate, [Ag(py)4]S2O8, a Reagent for the Oxidative Transformations" Bull. Chem. Soc. Jpn., Vol 65, p 2878-2880. (1992).