Tetrakis(acetonitrile)copper(I) hexafluorophosphate

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Tetrakis(acetonitrile)copper(I) hexafluorophosphate
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Names
IUPAC name
Tetrakis(acetonitrile)copper(I) hexafluorophosphate
Identifiers
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PubChem CID
Properties
[Cu(CH3CN)4]PF6
Molar mass 372.7198 g/mol
AppearanceWhite powder
Melting point 160 °C (320 °F; 433 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tetrakis(acetonitrile)copper(I) hexafluorophosphate is a salt with the formula [Cu(CH3CN)4]PF6. It is a colourless solid that is used in the synthesis of other copper complexes. The cation [Cu(CH3CN)4]+ is a well-known example of a transition metal nitrile complex. [1]

Contents

Structure

As confirmed by X-ray crystallographic studies, the copper(I) ion is coordinated to four almost linear acetonitrile ligands in a nearly ideal tetrahedral geometry. [2] [3] Similar complexes with other anions including the perchlorate, tetrafluoroborate, and nitrate are known. [1]

Synthesis

The cation was first reported in 1923 with a nitrate anion as a byproduct of the reduction of silver nitrate with a suspension of copper powder in acetonitrile. [4] [Cu(CH3CN)4]PF6 is generally produced by the addition of HPF6 to a suspension of copper(I) oxide in acetonitrile: [5]

Cu2O + 2 HPF6 + 8 CH3CN → 2 [Cu(CH3CN)4]PF6 + H2O

The reaction is highly exothermic, and may bring the solution to a boil. Upon crystallization, the resulting microcrystals should be white, though a blue tinge is common, indicating the presence of Cu2+ impurities. [5]

Reactions and applications

The acetonitrile ligands protect the Cu+ ion from oxidation to Cu2+, but are rather poorly bound: with other counterions, the complex forms di- [1] and tri-acetonitrilo [6] complexes and is also a useful source of unbound Cu(I). [5]

Water-immiscible organic nitriles have been shown to selectively extract Cu(I) from aqueous chloride solutions. [7] Through this method, copper can be separated from a mixture of other metals. Dilution of acetonitrile solutions with water induces disproportionation:

2 [Cu(CH3CN)4]+ + 6 H2O → [Cu(H2O)6]2+ + Cu + 8 CH3CN

See also

Related Research Articles

Acetonitrile, often abbreviated MeCN, is the chemical compound with the formula CH3CN and structure H3C−C≡N. This colourless liquid is the simplest organic nitrile. It is produced mainly as a byproduct of acrylonitrile manufacture. It is used as a polar aprotic solvent in organic synthesis and in the purification of butadiene. The N≡C−C skeleton is linear with a short C≡N distance of 1.16 Å.

<span class="mw-page-title-main">Copper(II) nitrate</span> Chemical compound

Copper(II) nitrate describes any member of the family of inorganic compounds with the formula Cu(NO3)2(H2O)x. The hydrates are blue solids. Anhydrous copper nitrate forms blue-green crystals and sublimes in a vacuum at 150-200 °C. Common hydrates are the hemipentahydrate and trihydrate.

Anions that interact weakly with cations are termed non-coordinating anions, although a more accurate term is weakly coordinating anion. Non-coordinating anions are useful in studying the reactivity of electrophilic cations. They are commonly found as counterions for cationic metal complexes with an unsaturated coordination sphere. These special anions are essential components of homogeneous alkene polymerisation catalysts, where the active catalyst is a coordinatively unsaturated, cationic transition metal complex. For example, they are employed as counterions for the 14 valence electron cations [(C5H5)2ZrR]+ (R = methyl or a growing polyethylene chain). Complexes derived from non-coordinating anions have been used to catalyze hydrogenation, hydrosilylation, oligomerization, and the living polymerization of alkenes. The popularization of non-coordinating anions has contributed to increased understanding of agostic complexes wherein hydrocarbons and hydrogen serve as ligands. Non-coordinating anions are important components of many superacids, which result from the combination of Brønsted acids and Lewis acids.

<span class="mw-page-title-main">Silver perchlorate</span> Chemical compound

Silver perchlorate is the chemical compound with the formula AgClO4. This white solid forms a monohydrate and is mildly deliquescent. It is a useful source of the Ag+ ion, although the presence of perchlorate presents risks. It is used as a catalyst in organic chemistry.

<span class="mw-page-title-main">Diazonium compound</span> Group of organonitrogen compounds

Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. The parent compound where R is hydrogen, is diazenylium.

<span class="mw-page-title-main">Copper(I) iodide</span> Chemical compound

Copper(I) iodide is the inorganic compound with the formula CuI. It is also known as cuprous iodide. It is useful in a variety of applications ranging from organic synthesis to cloud seeding.

In chemical nomenclature, the IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds, as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in Nomenclature of Inorganic Chemistry. Ideally, every inorganic compound should have a name from which an unambiguous formula can be determined. There is also an IUPAC nomenclature of organic chemistry.

<span class="mw-page-title-main">Tetrafluoroborate</span> Anion

Tetrafluoroborate is the anion BF
4
. This tetrahedral species is isoelectronic with tetrafluoroberyllate (BeF2−
4
), tetrafluoromethane (CF4), and tetrafluoroammonium (NF+
4
) and is valence isoelectronic with many stable and important species including the perchlorate anion, ClO
4
, which is used in similar ways in the laboratory. It arises by the reaction of fluoride salts with the Lewis acid BF3, treatment of tetrafluoroboric acid with base, or by treatment of boric acid with hydrofluoric acid.

<span class="mw-page-title-main">Hexafluorophosphate</span> Anion with the chemical formula PF6–

Hexafluorophosphate is an anion with chemical formula of [PF6]. It is an octahedral species that imparts no color to its salts. [PF6] is isoelectronic with sulfur hexafluoride, SF6, and the hexafluorosilicate dianion, [SiF6]2−, and hexafluoroantimonate [SbF6]. In this anion, phosphorus has a valence of 5. Being poorly nucleophilic, hexafluorophosphate is classified as a non-coordinating anion.

<span class="mw-page-title-main">Silver hexafluorophosphate</span> Chemical compound

Silver hexafluorophosphate, sometimes referred to "silver PF-6," is an inorganic compound with the chemical formula AgPF6.

<span class="mw-page-title-main">Triphenylmethyl hexafluorophosphate</span> Chemical compound

Triphenylmethyl hexafluorophosphate is an organic salt with the formula [(C6H5)3C]+[PF6], consisting of the triphenylcarbenium cation [(C6H5)3C]+ and the hexafluorophosphate anion [PF6].

<span class="mw-page-title-main">Rhodocene</span> Organometallic chemical compound

Rhodocene is a chemical compound with the formula [Rh(C5H5)2]. Each molecule contains an atom of rhodium bound between two planar aromatic systems of five carbon atoms known as cyclopentadienyl rings in a sandwich arrangement. It is an organometallic compound as it has (haptic) covalent rhodium–carbon bonds. The [Rh(C5H5)2] radical is found above 150 °C (302 °F) or when trapped by cooling to liquid nitrogen temperatures (−196 °C [−321 °F]). At room temperature, pairs of these radicals join via their cyclopentadienyl rings to form a dimer, a yellow solid.

<span class="mw-page-title-main">Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate</span> Chemical compound

Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate is an anion with chemical formula [{3,5-(CF3)2C6H3}4B], which is commonly abbreviated as [BArF4], indicating the presence of fluorinated aryl (ArF) groups. It is sometimes referred to as Kobayashi's anion in honour of Hiroshi Kobayashi who led the team that first synthesised it. More commonly it is affectionately nicknamed "BARF." The BARF ion is also abbreviated BArF24, to distinguish it from the closely related BArF
20
, [(C6F5)4B]. However, for a small group of chemists, the anion is abbreviated as TFPB otherwise, short for Tetrakis[3,5-bis(triFluoromethyl)Phenyl]Borate.

<span class="mw-page-title-main">Metal halides</span>

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.

Copper(I) nitrate is a proposed inorganic compound with formula of CuNO3. It has not been characterized by X-ray crystallography. It is the focus of one publication, which describes unsuccessful efforts to isolate the compound. Another nonexistent simple copper(I) compound derived from an oxyanion is cuprous perchlorate. On the other hand, cuprous sulfate is known.

<span class="mw-page-title-main">Brookhart's acid</span> Chemical compound

Brookhart's acid is the salt of the diethyl ether oxonium ion and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BAr′4). It is a colorless solid, used as a strong acid. The compound was first reported by Volpe, Grant, and Brookhart in 1992.

<span class="mw-page-title-main">Difluorophosphate</span> Chemical compound

Difluorophosphate or difluorodioxophosphate or phosphorodifluoridate is an anion with formula PO2F−2. It has a single negative charge and resembles perchlorate and monofluorosulfonate in shape and compounds. These ions are isoelectronic, along with tetrafluoroaluminate, phosphate, orthosilicate, and sulfate. It forms a series of compounds. The ion is toxic to mammals as it causes blockage to iodine uptake in the thyroid. However it is degraded in the body over several hours.

<span class="mw-page-title-main">Transition metal nitrile complexes</span> Class of coordination compounds containing nitrile ligands (coordinating via N)

Transition metal nitrile complexes are coordination compounds containing nitrile ligands. Because nitriles are weakly basic, the nitrile ligands in these complexes are often labile.

<span class="mw-page-title-main">Transition metal pyridine complexes</span>

Transition metal pyridine complexes encompass many coordination complexes that contain pyridine as a ligand. Most examples are mixed-ligand complexes. Many variants of pyridine are also known to coordinate to metal ions, such as the methylpyridines, quinolines, and more complex rings.

<span class="mw-page-title-main">Tetrakis(acetonitrile)copper(I) tetrafluoroborate</span> Chemical compound

Tetrakis(acetonitrile)copper(I) tetrafluoroborate is a complex compound of copper with acetonitrile as the ligand and tetrafluoroborate as the counterion.

References

  1. 1 2 3 Silvana F. Rach, Fritz E. Kühn "Nitrile Ligated Transition Metal Complexes with Weakly Coordinating Counteranions and Their Catalytic Applications" Chem. Rev., 2009, volume 109, pp 2061–2080. doi : 10.1021/cr800270h
  2. Kierkegaard C.P.; Norrestam R. (1975). "Copper(I) tetraacetonitrile perchlorate". Acta Crystallogr. B . 31 (1): 314–317. Bibcode:1975AcCrB..31..314C. doi:10.1107/S0567740875002634.
  3. Black, J. R.; Levason, W.; Webster, M. (1995). "Tetrakis(acetonitrile-N)copper(I) Hexafluorophosphate(V) Acetonitrile Solvate". Acta Crystallographica Section C Crystal Structure Communications. 51 (4): 623–625. Bibcode:1995AcCrC..51..623B. doi:10.1107/S0108270194012527.
  4. Morgan, H.H.; Sand, Henry Julics Salomon (1923). "Preparation and Stability of Cuprous Nitrate and Other Cuprous Salts in the Presence of Nitriles". J. Chem. Soc. 19: 2901. doi:10.1039/CT9232302901.
  5. 1 2 3 Kubas, G.J. (1990). Tetrakis(acetonitirile)copper(I) Hexaflurorophosphate. Inorganic Syntheses. Vol. 28. pp. 68–69. doi:10.1002/9780470132593.ch15.
  6. Elsayed Moussa, Mehdi; Piesch, Martin; Fleischmann, Martin; Schreiner, Andrea; Seidl, Michael; Scheer, Manfred (2018). "Highly soluble Cu(i)-acetonitrile salts as building blocks for novel phosphorus-rich organometallic-inorganic compounds" (PDF). Dalton Transactions. 47 (45): 16031–16035. doi:10.1039/C8DT03723J. PMID   30321246.
  7. Preston, J. S.; Muhr D. M; Parker A. J. (1980). "Cuprous hydrometallurgy: Part VIII. Solvent extraction and recovery of copper(I) chloride with organic nitriles from an iron(III), copper(II) chloride, two-step oxidative leach of chalcopyrite concentrate". Hydrometallurgy . 5 (2): 227. Bibcode:1980HydMe...5..227P. doi:10.1016/0304-386X(80)90041-9.