Dipotassium tetrachloroplatinate
[CAS# 10025-99-7]

Identification

• Classification: Food additive >> Nutrition supplements >> Inorganic salts
• Name: Dipotassium tetrachloroplatinate
• Synonyms: Potassium tetrachloroplatinate(II)
• Molecular Formula: K₂PtCl₄
• Molecular Weight: 415.08
• CAS Registry Number: 10025-99-7
• EC Number: 233-050-9
• SMILES: Cl[Pt-2](Cl)(Cl)Cl.[K+].[K+]

Properties

• Density: 3.38 g/mL (Expl.)
• Melting point: (Decomposes) (Expl.)
• Solubility: 10 g/L (20 °C) (Expl.)

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07;GHS08;GHS09 Danger
• Risk Statements: H290-H301-H315-H317-H318-H334-H400-H410
• Safety Statements: P233-P234-P260-P261-P264-P264+P265-P270-P271-P272-P273-P280-P284-P301+P316-P302+P352-P304+P340-P305+P354+P338-P317-P321-P330-P332+P317-P333+P317-P342+P316-P362+P364-P390-P391-P403-P405-P406-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Skin irritation	Skin Irrit.	2	H315
Respiratory sensitization	Resp. Sens.	1	H334
Skin sensitization	Skin Sens.	1	H317
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	2	H300
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute toxicity	Acute Tox.	3	H301
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Respiratory sensitization	Resp. Sens.	1A	H334
Skin sensitization	Skin Sens.	1B	H317

• Transport Information: UN 3288

Discovery and Applications

Dipotassium tetrachloroplatinate, with the chemical formula K₂PtCl₄, is a well-known platinum(II) coordination compound. Its discovery can be traced back to the 19th century during the systematic investigation of platinum salts. Early studies of platinum chemistry were driven by the metal’s remarkable resistance to corrosion and its unique catalytic properties. Dipotassium tetrachloroplatinate was synthesized by dissolving elemental platinum in aqua regia to form chloroplatinic acid (H₂PtCl₆), followed by neutralization with potassium chloride, leading to the formation of K₂PtCl₄ upon crystallization.

The crystallographic characterization of dipotassium tetrachloroplatinate revealed that it forms red to orange crystalline solids that are soluble in water but less soluble in alcohols. The platinum center is coordinated in a square planar geometry by four chloride ligands, a typical arrangement for platinum(II) complexes. This structural feature was confirmed by X-ray crystallography and spectroscopic analyses, providing a deeper understanding of the coordination chemistry of platinum.

Dipotassium tetrachloroplatinate has significant applications, particularly in the synthesis of other platinum compounds. It serves as an important starting material for the preparation of a wide range of platinum complexes, including both platinum(II) and platinum(IV) species. Many organoplatinum compounds used in catalysis, materials science, and medicinal chemistry are synthesized through substitution reactions involving K₂PtCl₄.

One of the most notable applications of dipotassium tetrachloroplatinate is in the production of cisplatin, cis-diamminedichloroplatinum(II), a groundbreaking anticancer drug. The preparation of cisplatin involves the reaction of K₂PtCl₄ with ammonia under controlled conditions, selectively replacing two chloride ligands with ammine ligands in a cis configuration. Cisplatin’s discovery and clinical success highlighted the importance of K₂PtCl₄ as a crucial precursor in pharmaceutical chemistry.

In addition to medicinal chemistry, dipotassium tetrachloroplatinate is employed in electroplating processes, where platinum coatings are valued for their durability, electrical conductivity, and resistance to tarnishing. It is also used as a reagent in analytical chemistry, particularly in gravimetric analysis, to precipitate potassium as potassium hexachloroplatinate(VI) for quantitative determination.

Catalysis represents another significant area where dipotassium tetrachloroplatinate finds utility. It is used to prepare various platinum catalysts that are active in hydrogenation, hydrosilylation, and oxidation reactions. The ability to tailor the ligand environment around platinum through substitution of the chloride ligands in K₂PtCl₄ allows for the fine-tuning of catalyst properties to suit specific reactions.

Furthermore, dipotassium tetrachloroplatinate has applications in materials science. It is used to produce platinum nanoparticles and thin films, which are integral components in the development of sensors, fuel cells, and other electronic devices. The compound’s aqueous solubility and chemical reactivity make it suitable for solution-based methods of nanoparticle synthesis, such as chemical reduction processes.

Overall, dipotassium tetrachloroplatinate remains a substance of great importance in various fields of chemistry and industry, owing to its well-characterized structure, reliable reactivity, and versatility as a precursor to a multitude of platinum-based materials and compounds.

References

1997. Immunostimulatory Effects of Platinum Compounds: Correlation between Sensitizing Properties in vivo and Modulation of Receptor-Mediated Endocytosis in vitro. International Archives of Allergy and Immunology, 112(2).
DOI: 10.1159/000237442

2008. Speciation of inorganic platinum-chloride complexes in spiked environmental samples by SPE and ICP-AES. Analytica Chimica Acta, 616(1).
DOI: 10.1016/j.aca.2008.03.037

2013. Occupational Immediate-Type Allergic Asthma due to Potassium Tetrachloroplatinate in Production of Cytotoxic Drugs. Advances in Experimental Medicine and Biology, 755.
DOI: 10.1007/978-94-007-4546-9_6