Platinum(II) chloride

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Platinum(II) chloride
PtCl2.jpg
Beta-platinum(II)-chloride-from-xtal-3D-balls-A.png
Names
IUPAC name
Platinum(II) chloride
Other names
Platinous chloride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.019 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-034-1
1744965
PubChem CID
UNII
  • InChI=1S/2ClH.Pt/h2*1H;/q;;+2/p-2 Yes check.svgY
    Key: CLSUSRZJUQMOHH-UHFFFAOYSA-L Yes check.svgY
  • InChI=1/2ClH.Pt/h2*1H;/q;;+2/p-2
    Key: CLSUSRZJUQMOHH-NUQVWONBAP
  • monomer:Cl[Pt]Cl
  • hexamer:[Cl+]0[Pt-2]12[Cl+][Pt-2]34[Cl+][Pt-2]05[Cl+][Pt-2]6([Cl+]1)[Cl+][Pt-2]([Cl+]2)([Cl+]3)[Cl+][Pt-2]([Cl+]4)([Cl+]5)[Cl+]6
Properties
Pt Cl 2
Molar mass 265.99 g/mol
Appearanceolive green crystals
Density 6.05 g/cm3, solid
Melting point 581 °C (1,078 °F; 854 K)
Boiling point decomposes
insoluble
Solubility insoluble in alcohol, ether
soluble in HCl, ammonia
54.0·10−6 cm3/mol
Structure
hexagonal
Hazards
GHS labelling: [1]
GHS-pictogram-acid.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H314, H315, H317, H319, H334
P260, P261, P264, P272, P280, P285, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P310, P321, P332+P313, P333+P313, P337+P313, P342+P311, P362, P363, P405, P501
Lethal dose or concentration (LD, LC):
3423 mg/kg (rat, oral)
Related compounds
Other anions
Platinum(II) bromide
Platinum(II) sulfide
Other cations
Palladium(II) chloride
Related compounds
Platinum(IV) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Platinum(II) chloride is the chemical compound Pt Cl2. It is an important precursor used in the preparation of other platinum compounds. It exists in two crystalline forms, but the main properties are somewhat similar: dark brown, insoluble in water, diamagnetic, and odorless.

Contents

Structure

The structures of PtCl2 and PdCl2 are similar. These dichlorides exist in both polymeric, or "α", and hexameric, or "β" structures. The β form converts to the α form at 500 °C. In the β form, the Pt-Pt distances are 3.32–3.40 Å, indicative of some bonding between the pairs of metals. In both forms of PtCl2, each Pt center is four-coordinate, being surrounded by four chloride ligands. Complementarily, each Cl center is two-coordinate, being connected to two platinum atoms. [2] The structure of α-PtCl2 is reported to be disordered and contain edge- and/or corner-sharing square-planar PtCl4 units. [3]

Evolution of b-PtCl2 structure: Start with cubic lattice, remove corner and centered lattice points, inscribe octahedron (red lines), label corners as X (twelve Cl centers) and face-centered atoms as M (six Pt(II) centers). Beta-PdCl2.png
Evolution of β-PtCl2 structure: Start with cubic lattice, remove corner and centered lattice points, inscribe octahedron (red lines), label corners as X (twelve Cl centers) and face-centered atoms as M (six Pt(II) centers).

Preparation

β-PtCl2 is prepared by heating chloroplatinic acid to 350 °C in air. [4]

H2PtCl6 → PtCl2 + Cl2 + 2 HCl

This method is convenient since the chloroplatinic acid is generated readily from Pt metal. Aqueous solutions of H2PtCl6 can also be reduced with hydrazinium salts, but this method is more laborious than the thermal route of Kerr and Schweizer.

Although PtCl2 must form when platinum metal contacts hot chlorine gas, this process suffers from over-chlorination to give PtCl4. Berzelius and later Wöhler and Streicher showed that upon heating to 450 °C, this Pt(IV) compound decomposes to the Pt(II) derivative: [5]

PtCl4 → PtCl2 + Cl2

Transformations such as this are "driven" by entropy, the free energy gained upon the release of a gaseous product from a solid. Upon heating to still higher temperatures, PtCl2 releases more chlorine to give metallic Pt. This conversion is the basis of the gravimetric assay of the purity of the PtCl2 product.

Uses

Most reactions of PtCl2 proceed via treatment with ligands (L) to give molecular derivatives. These transformations entail depolymerization via cleavage of Pt-Cl-Pt linkages:

PtCl2 + 2 L → PtCl2L2

Sometimes, such reactions can be deceptive. Addition of ammonia gives initially "PtCl2(NH3)2", but this material is in fact Magnus's green salt, [Pt(NH3)4][PtCl4].

Of the many such complexes that have been described, the following are illustrative: [6]

Several of these compounds are of interest in homogeneous catalysis in the service of organic synthesis or as anti-cancer drugs.

See also

Related Research Articles

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

Phosphorus trichloride is an inorganic compound with the chemical formula PCl3. A colorless liquid when pure, it is an important industrial chemical, being used for the manufacture of phosphites and other organophosphorus compounds. It is toxic and reacts readily with water to release hydrogen chloride.

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

Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is useful for preparing other iridium compounds. The anhydrous salt is a dark green crystalline solid. More commonly encountered is the trihydrate IrCl3(H2O)3.

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

Palladium(II) chloride, also known as palladium dichloride and palladous chloride, are the chemical compounds with the formula PdCl2. PdCl2 is a common starting material in palladium chemistry – palladium-based catalysts are of particular value in organic synthesis. It is prepared by the reaction of chlorine with palladium metal at high temperatures.

<span class="mw-page-title-main">Metal ammine complex</span>

In coordination chemistry, metal ammine complexes are metal complexes containing at least one ammonia ligand. "Ammine" is spelled this way due to historical reasons; in contrast, alkyl or aryl bearing ligands are spelt with a single "m". Almost all metal ions bind ammonia as a ligand, but the most prevalent examples of ammine complexes are for Cr(III), Co(III), Ni(II), Cu(II) as well as several platinum group metals.

The Reformatsky reaction is an organic reaction which condenses aldehydes or ketones with α-halo esters using metallic zinc to form β-hydroxy-esters:

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

Chloroplatinic acid (also known as hexachloroplatinic acid) is an inorganic compound with the formula [H3O]2[PtCl6](H2O)x (0 ≤ x ≤ 6). A red solid, it is an important commercial source of platinum, usually as an aqueous solution. Although often written in shorthand as H2PtCl6, it is the hydronium (H3O+) salt of the hexachloroplatinate anion (PtCl2−
6
). Hexachloroplatinic acid is highly hygroscopic.

Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula C8H12, specifically [−(CH2)2−CH=CH−]2.

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

Tungsten hexachloride is the chemical compound of tungsten and chlorine with the formula WCl6. This dark violet blue species exists as a volatile solid under standard conditions. It is an important starting reagent in the preparation of tungsten compounds. Other examples of charge-neutral hexachlorides are rhenium(VI) chloride and molybdenum(VI) chloride. The highly volatile tungsten hexafluoride is also known.

<span class="mw-page-title-main">Zeise's salt</span> Chemical compound

Zeise's salt, potassium trichloro(ethylene)platinate(II) hydrate, is the chemical compound with the formula K[PtCl3(C2H4)]·H2O. The anion of this air-stable, yellow, coordination complex contains an η2-ethylene ligand. The anion features a platinum atom with a square planar geometry. The salt is of historical importance in the area of organometallic chemistry as one of the first examples of a transition metal alkene complex and is named for its discoverer, William Christopher Zeise.

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

Platinum(IV) chloride is the inorganic compound of platinum and chlorine with the empirical formula PtCl4. This brown solid features platinum in the 4+ oxidation state.

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

Ammonium hexachloroplatinate, also known as ammonium chloroplatinate, is the inorganic compound with the formula (NH4)2[PtCl6]. It is a rare example of a soluble platinum(IV) salt that is not hygroscopic. It forms intensely yellow solutions in water. In the presence of 1M NH4Cl, its solubility is only 0.0028 g/100 mL.

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

Potassium tetrachloroplatinate(II) is the chemical compound with the formula K2PtCl4. This reddish orange salt is an important reagent for the preparation of other coordination complexes of platinum. It consists of potassium cations and the square planar dianion PtCl42−. Related salts are also known including Na2PtCl4, which is brown-colored and soluble in alcohols, and quaternary ammonium salts, which are soluble in a broader range of organic solvents.

Organoplatinum chemistry is the chemistry of organometallic compounds containing a carbon to platinum chemical bond, and the study of platinum as a catalyst in organic reactions. Organoplatinum compounds exist in oxidation state 0 to IV, with oxidation state II most abundant. The general order in bond strength is Pt-C (sp) > Pt-O > Pt-N > Pt-C (sp3). Organoplatinum and organopalladium chemistry are similar, but organoplatinum compounds are more stable and therefore less useful as catalysts.

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

Sodium hexachloroplatinate(IV), the sodium salt of chloroplatinic acid, is an inorganic compound with the formula Na2[PtCl6], consisting of the sodium cation and the hexachloroplatinate anion. As explained by Cox and Peters, anhydrous sodium hexachloroplatinate, which is yellow, tends to form the orange hexahydrate upon storage in humid air. The latter can be dehydrated upon heating at 110 °C.

<span class="mw-page-title-main">Metal halides</span>

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.

<span class="mw-page-title-main">Bis(triphenylphosphine)platinum chloride</span> Chemical compound

Bis(triphenylphosphine)platinum chloride is a metal phosphine complex with the formula PtCl2[P(C6H5)3]2. Cis- and trans isomers are known. The cis isomer is a white crystalline powder, while the trans isomer is yellow. Both isomers are square planar about the central platinum atom. The cis isomer is used primarily as a reagent for the synthesis of other platinum compounds.

<span class="mw-page-title-main">Imidoyl chloride</span>

Imidoyl chlorides are organic compounds that contain the functional group RC(NR')Cl. A double bond exist between the R'N and the carbon centre. These compounds are analogues of acyl chloride. Imidoyl chlorides tend to be highly reactive and are more commonly found as intermediates in a wide variety of synthetic procedures. Such procedures include Gattermann aldehyde synthesis, Houben-Hoesch ketone synthesis, and the Beckmann rearrangement. Their chemistry is related to that of enamines and their tautomers when the α hydrogen is next to the C=N bond. Many chlorinated N-heterocycles are formally imidoyl chlorides, e.g. 2-chloropyridine, 2, 4, and 6-chloropyrimidines.

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

trans-Dichlorodiammineplatinum(II) is the trans isomer of the coordination complex with the formula trans-PtCl2(NH3)2, sometimes called transplatin. It is a yellow solid with low solubility in water but good solubility in DMF. The existence of two isomers of PtCl2(NH3)2 led Alfred Werner to propose square planar molecular geometry. It belongs to the molecular symmetry point group D2h.

<span class="mw-page-title-main">Transition metal azide complex</span>

Transition metal azide complexes are coordination complexes containing one or more azide (N3) ligands.

References

  1. "Platinum(II) chloride". pubchem.ncbi.nlm.nih.gov. Retrieved 27 December 2021.
  2. Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. ISBN   0-12-352651-5.
  3. Krebs, Bernt; Brendel, Claus; Schäfer, Harald (1988). "Neue Untersuchungen an α‐Platindichlorid Darstellung und Struktur". Z. Anorg. Allg. Chem. 561 (1): 119–131. doi:10.1002/zaac.19885610113.
  4. Kerr, G. T.; Schweizer, A. E. (1980). β-Platinum(II) Chloride. Inorg. Synth. Inorganic Syntheses. Vol. 20. pp.  48–49. doi:10.1002/9780470132517.ch14. ISBN   978-0-470-13251-7.
  5. Wöhler, L.; Streicher, S. (1913). "Über das Beständigkeitsgebiet von vier wasserfreien Platinchloriden, über die Flüchtigkeit des Metalls im Chlorgas und die Darstellung sauerstoff-freien Chlors". Chem. Ber. 46 (2): 1591–1597. doi:10.1002/cber.19130460252.
  6. Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. ISBN   0-7514-0413-6