What Is Ruthenium Chloride?
Ruthenium chloride, typically referred to as ruthenium(III) chloride (RuCl3), is a compound of chlorine and ruthenium. It is primarily encountered as a hydrate, RuCl3・xH2O, which is more commonly used than the anhydrous form. These compounds are dark brown to black and serve as important precursors for various ruthenium-based materials.
Uses of Ruthenium Chloride
Ruthenium chloride hydrates are versatile precursors used in preparing ruthenium catalysts for organic synthesis, including asymmetric hydrogenation and metathesis reactions. They are also key in developing ruthenium plating solutions, which offer a cost-effective alternative to rhodium plating. Further applications include the production of electrodes and as catalysts in precious metal processes.
Properties of Ruthenium Chloride
With a melting point of around 500°C, ruthenium chloride exists as a black or dark brown solid at room temperature. It forms a variety of compounds and exhibits multiple oxidation states, such as +2, +3, and +4. The hydrates, particularly the monohydrate and trihydrate, are crucial for synthesizing other ruthenium compounds.
Structure of Ruthenium Chloride
Ruthenium chloride can assume alpha and beta crystal forms, with the alpha form being insoluble in water and ethanol, while the beta form is soluble in ethanol. The beta form can irreversibly convert to the alpha form upon heating.
Other Information on Ruthenium Chloride
1. Reaction of Ruthenium Chloride
Ruthenium chloride reacts with carbon monoxide under mild conditions to form various carbonylated complexes. These reactions can lead to the synthesis of complexes with different ligands, showcasing the compound’s versatility in coordination chemistry.
2. Compounds Synthesized From Ruthenium Chloride
Examples of compounds that can be synthesized using ruthenium chloride as a raw material include RuCl2(PPh3)3, [[RuCl2(C6H6)]2, RuCl2(C5Me5)2, [Ru(bpy)3]Cl2, and Ru(C5H7O2)3. All can be synthesized from the hydrate RuCl3・xH2O.
For example, RuCl2(PPh3)3 and [RuCl2(C6H6)]2 are chocolate-colored, while RuCl2(PPh3)3 is soluble in benzene. Aromatic hydrocarbons such as hexamethylbenzene can also be used as a ligand for [RuCl2(C6H6)]2; Ru(C5H7O2)3 is soluble in benzene.