Potassium tetrachloroplatinate

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Potassium tetrachloroplatinate
K2PtCl4.png
Potassium-tetrachloroplatinate-xtal-1990-C-3D-balls.png
Potassium tetrachloroplatinate.jpg
Names
IUPAC name
Potassium tetrachloridoplatinate(2–)
Other names
Potassium chloroplatinite
Identifiers
3D model (Jmol)
ChemSpider
ECHA InfoCard 100.030.034
EC Number 233-050-9
UNII
Properties
K2PtCl4
Molar mass 415.09 g/mol
Appearance reddish solid
Density 3.38 g/cm3
Melting point 265 °C (509 °F; 538 K)
0.93 g/100 mL (16 °C)
5.3/100 mL (100 °C)
Hazards
Toxic (T)
Irritant (Xi)
R-phrases R25, R41, R42, R43
S-phrases S23, S24, S26, S37
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions
Potassium hexachloroplatinate
Other cations
Sodium chloroplatinate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.

Preparation[edit]

Potassium tetrachloroplatinate is prepared by reduction of the corresponding hexachloroplatinate salt with hydrazine.[1] K2PtCl4 is one of the salts that is most easily obtained from platinum ores. The complex is appreciably soluble only in water. Treatment with alcohols, especially in the presence of base, causes reduction to platinum metal. Conversion to organic salts, such as [PPN]2PtCl4 are soluble in chlorocarbons.[2]

Reactions[edit]

The chloride ligands on [PtCl4]2− are displaced by many other ligands. Upon reaction with triphenylphosphine, [PtCl4]2− converts to cis-bis(triphenylphosphine)platinum chloride:

PtCl42− + 2 PPh3cis-PtCl2(PPh3)2 + 2 Cl

The anti-cancer drug Cisplatin can similarly be prepared:[1]

PtCl42− + 2 NH3cis-PtCl2(NH3)2 + 2 Cl

Enedithiolates displace all four chloride ligands to give bis(dithiolene) complexes.[3] Reduction gives colloidal platinum of potential interest in for catalysis.[4]

Historically, an important reaction involves ammonia and [PtCl4]2−. This reaction affords a deep green precipitate with the formula PtCl2(NH3)2. This material, known as Magnus' green salt, is a semiconducting coordination polymer consisting of chains of alternating [PtCl4]2− and [Pt(NH3)4]2+ centres.[5]

References[edit]

  1. ^ a b Keller, R. N.; Moeller, T. (1963). "Potassium Tetrachloroplatinate(II)". Inorg. Synth. Inorganic Syntheses. 7: 247–250. doi:10.1002/9780470132333.ch79. ISBN 9780470132333. 
  2. ^ Elding, L. I.; Oskarsson, A.; Kukushkin, V. Yu (1997). "Platinum Complexes Suitable as Precursors for Synthesis in Nonaqueous Solvents". Inorg. Synth. Inorganic Syntheses. 31: 276–279. doi:10.1002/9780470132623.ch47. ISBN 9780470132623. 
  3. ^ Scott D. Cummings; Richard Eisenberg (1995). "Acid-Base Behavior of the Ground and Excited States of Platinum(II) Complexes of Quinoxaline-2,3-dithiolate". Inorg. Chem. 34 (13): 3396–3403. doi:10.1021/ic00117a005. 
  4. ^ Ahmadi, T. S.; Wang, Z. L.; Green, T. C.; Henglein, A.; El-Sayed, M. A. (1996). "Shape-Controlled Synthesis of Colloidal Platinum Nanoparticles". Science. 272 (5270): 1924ff. doi:10.1126/science.272.5270.1924. PMID 8662492. 
  5. ^ Caseri, W. (2004). "Derivatives of Magnus' green salt; from intractable materials to solution-processed transistors". Platinum Metals Review. 48 (3): 91–100. doi:10.1595/147106704X1504.