Tetrakis(acetonitrile)copper(I) hexafluorophosphate
[CAS# 64443-05-6]

Identification

• Classification: Organic raw materials >> Organometallic compound >> Organic copper
• Name: Tetrakis(acetonitrile)copper(I) hexafluorophosphate
• Synonyms: Copper(1+) hexafluorophosphate - acetonitrile (1:1:4)
• Molecular Formula: C₈H₁₂CuF₆N₄P
• Molecular Weight: 372.72
• CAS Registry Number: 64443-05-6
• EC Number: 672-617-9
• SMILES: CC#N.CC#N.CC#N.CC#N.F[P-](F)(F)(F)(F)F.[Cu+]

Properties

• Melting point: 160 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319

Discovery and Applications

Tetrakis(acetonitrile)copper(I) hexafluorophosphate is a coordination compound composed of a copper(I) ion coordinated to four acetonitrile ligands and paired with a hexafluorophosphate anion. This compound is notable for its versatility in various chemical reactions, particularly in the fields of organometallic chemistry and catalysis. Its discovery and subsequent applications highlight its significance as a reagent and precursor in numerous synthetic processes.

The synthesis of Tetrakis(acetonitrile)copper(I) hexafluorophosphate can be traced back to advancements in coordination chemistry during the mid-20th century. The compound is typically prepared by the reaction of copper(I) salts, such as copper(I) chloride, with acetonitrile in the presence of a hexafluorophosphate source, such as ammonium hexafluorophosphate. The reaction yields a stable, white crystalline solid, characterized by its high solubility in polar organic solvents, particularly acetonitrile.

This compound’s structure features a central copper(I) ion coordinated by four acetonitrile molecules, which provide a stable and inert environment for the copper center. The hexafluorophosphate anion serves as a non-coordinating counterion, maintaining the overall charge balance of the complex. The coordination geometry around the copper(I) ion is typically tetrahedral, which is characteristic of copper(I) complexes.

Tetrakis(acetonitrile)copper(I) hexafluorophosphate is widely utilized as a catalyst or catalyst precursor in organic synthesis. Its ability to activate a variety of substrates makes it particularly useful in cycloaddition reactions, such as the Huisgen 1,3-dipolar cycloaddition, commonly referred to as the “click reaction.” In this context, the compound facilitates the formation of 1,2,3-triazoles by catalyzing the reaction between azides and alkynes, a process that has found widespread application in materials science, medicinal chemistry, and bioconjugation techniques.

Another significant application of Tetrakis(acetonitrile)copper(I) hexafluorophosphate is in the formation of copper(I)-catalyzed carbon-carbon and carbon-heteroatom bond-forming reactions. These reactions include cross-coupling processes, such as the Ullmann reaction, where the compound acts as a source of copper(I) to promote the coupling of aryl halides with nucleophiles, leading to the formation of biaryl compounds or other functionalized aromatic molecules.

In addition to its catalytic properties, Tetrakis(acetonitrile)copper(I) hexafluorophosphate is also employed as a precursor in the synthesis of other copper(I) complexes. The labile nature of the acetonitrile ligands allows for facile substitution with a variety of other ligands, enabling the preparation of a wide range of copper(I) coordination compounds with tailored properties for specific applications. This versatility has made it a valuable tool in the development of new materials, particularly in the field of coordination polymers and metal-organic frameworks (MOFs).

Furthermore, the compound's role in photophysical studies cannot be overlooked. Tetrakis(acetonitrile)copper(I) hexafluorophosphate has been investigated for its luminescent properties, which are of interest in the development of light-emitting devices and sensors. The compound’s luminescence arises from metal-to-ligand charge transfer (MLCT) transitions, which can be tuned by modifying the ligand environment around the copper center.

Despite its widespread utility, the compound must be handled with care due to the potential sensitivity of copper(I) complexes to air and moisture, which can lead to oxidation and degradation of the compound. Proper storage and handling under inert conditions are essential to maintain the integrity and reactivity of Tetrakis(acetonitrile)copper(I) hexafluorophosphate in synthetic applications.

In summary, Tetrakis(acetonitrile)copper(I) hexafluorophosphate is a versatile coordination compound that has found extensive use in organic synthesis, catalysis, and materials science. Its ability to facilitate a variety of chemical transformations, coupled with its role as a precursor for other copper(I) complexes, underscores its importance in the toolkit of modern chemists. As research in coordination chemistry continues to evolve, the applications of this compound are likely to expand further, solidifying its place in the field of inorganic and organometallic chemistry.

References

2023. Recent advances in the construction of axially chiral arylpyrroles. Science China Chemistry, 66(10).
DOI: 10.1007/s11426-023-1671-y

2024. N-glycoside synthesis through combined copper- and photoredox-catalysed N-glycosylation of N-nucleophiles. Nature Synthesis, 3(4).
DOI: 10.1038/s44160-024-00496-7

2024. Copper-catalyzed enantioselective desymmetrizing C(sp2)-H functionalization of azide-ynamides via α-imino copper carbenes. Science China Chemistry, 67(7).
DOI: 10.1007/s11426-024-1990-y