Tetraammineplatinum dinitrate
[CAS# 20634-12-2]

Identification

• Classification: Organic raw materials >> Organometallic compound >> Organic hafnium, mercury, silver, platinum, etc.
• Name: Tetraammineplatinum dinitrate
• Synonyms: Azane;platinum(2+) dinitrate
• Molecular Formula: (NH₃)₄^.Pt(NO₃)₂
• Molecular Weight: 387.21
• CAS Registry Number: 20634-12-2
• EC Number: 243-929-9
• SMILES: N.N.N.N.[N+](=O)([O-])[O-].[N+](=O)([O-])[O-].[Pt+2]

Properties

• Density: 1.05 g/mL (Expl.)
• Melting point: 262 ºC (Decomposes) (Expl.)

Safety Data

• Hazard Symbols: GHS01;GHS03;GHS07 Danger
• Hazard Statements: H240-H272-H315-H317-H319-H335-H412
• Precautionary Statements: P210-P220-P234-P235-P240-P261-P264-P264+P265-P271-P272-P273-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P333+P317-P337+P317-P362+P364-P370+P372+P380+P373-P370+P378-P403-P403+P233-P405-P410-P411-P420-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Oxidising solids	Ox. Sol.	2	H272
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin sensitization	Skin Sens.	1	H317
Unstable Explosives	Unst. Expl.		H200
Self-reactive substances or mixtures	Self-react.	A	H240

• Transport Information: UN 1479

Discovory and Applicatios

Tetraammineplatinum dinitrate is an inorganic coordination compound consisting of a platinum(II) center coordinated by four ammonia (NH₃) ligands, forming the cationic complex \[Pt(NH₃)₄]²⁺, paired with two nitrate (NO₃⁻) anions to maintain charge neutrality. The compound is generally represented by the formula [Pt(NH₃)₄](NO₃)₂.

This complex belongs to the class of platinum ammine compounds, which are of significant interest in coordination chemistry due to their well-defined geometry and reactivity. The platinum ion in this compound is in the +2 oxidation state, typically exhibiting a square planar coordination geometry, characteristic of d⁸ metal centers such as platinum(II).

The synthesis of tetraammineplatinum dinitrate involves the reaction of platinum salts, commonly potassium tetrachloroplatinate(II) (K₂PtCl₄), with an excess of ammonia in aqueous solution. During the reaction, the chloride ligands are displaced by ammonia molecules, and subsequent treatment with nitric acid or nitrate salts facilitates the formation of the dinitrate salt. The resulting compound crystallizes as a solid with characteristic coordination properties.

Structurally, the \[Pt(NH₃)₄]²⁺ cation is a square planar complex, where the platinum center is surrounded by four ammonia ligands arranged at approximately 90° angles. The nitrate ions are present as counterions and do not coordinate directly to the platinum but interact via ionic bonds and hydrogen bonding in the crystal lattice.

Tetraammineplatinum dinitrate serves as an important intermediate in platinum chemistry, particularly in the preparation of other platinum complexes and catalysts. It provides a convenient platform for ligand substitution reactions, allowing the introduction of various ligands to tailor the complex’s chemical and physical properties.

This compound has also been studied in the context of medicinal chemistry, as platinum ammine complexes form the basis of several chemotherapeutic agents. Although tetraammineplatinum dinitrate itself is not a drug, understanding its properties aids in the development and design of platinum-based drugs such as cisplatin and related analogs.

Analytical characterization of tetraammineplatinum dinitrate includes techniques such as nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and X-ray crystallography to elucidate its structure and purity. Its square planar geometry leads to characteristic electronic transitions observable in UV-Vis spectra.

In terms of physical properties, the compound typically appears as a crystalline solid soluble in water and polar solvents due to the ionic nature of the nitrate salts and the polarity of the ammine ligands. It is stable under ambient conditions but can undergo ligand substitution or redox reactions under specific chemical environments.

Safety precautions when handling tetraammineplatinum dinitrate include avoiding inhalation, ingestion, or prolonged skin contact, as platinum compounds can be toxic and sensitizing. Proper laboratory safety practices involve the use of gloves, protective eyewear, and working in well-ventilated areas.

In summary, tetraammineplatinum dinitrate is a square planar platinum(II) complex coordinated by four ammonia ligands, balanced by two nitrate anions. It is a key compound in coordination chemistry and platinum complex synthesis, serving as a versatile intermediate in both industrial and research applications related to platinum chemistry.

References

2024. Diversity of Crystal Structures in a System Containing Complex Ions [Pt(NH3)4]2+ and [Rh(C2O4)3]3-. Journal of Structural Chemistry, 65(6).
DOI: 10.1134/s0022476624060052

2022. TETRAAMMINOPLATINUM(II) PARAMOLYBDATE. SYNTHESIS, CRYSTAL STRUCTURE, THERMAL PROPERTIES. Journal of Structural Chemistry, 63(8).
DOI: 10.1134/s0022476622080157

2022. Electrocatalysts with strong electrostatic adsorption for improving the activity and stability of the oxygen reduction reaction in a polymer electrolyte membrane fuel cell. Journal of Applied Electrochemistry, 52(12).
DOI: 10.1007/s10800-022-01810-x