Copper(I) cyanide

Last updated
Copper(I) cyanide
Alpha-CuCN-unit-cell-CM-3D-balls.png
Copper(I) cyanide A.jpg
Names
IUPAC name
Copper(I) cyanide
Other names
Cuprous cyanide, copper cyanide, cupricin
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.008.076 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 208-883-6
PubChem CID
RTECS number
  • GL7150000
UNII
UN number 1587
  • InChI=1S/CN.Cu/c1-2;/q-1;+1 Yes check.svgY
    Key: DOBRDRYODQBAMW-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/CN.Cu/c1-2;/q-1;+1
    Key: DOBRDRYODQBAMW-UHFFFAOYAI
  • [Cu+].[C-]#N
Properties
CuCN
Molar mass 89.563 g/mol
Appearanceoff-white / pale yellow powder
Density 2.92 g/cm3 [1]
Melting point 474 °C (885 °F; 747 K)
negligible
3.47×10−20 [2]
Solubility insoluble in ethanol, cold dilute acids;
soluble in NH4OH, KCN
Structure
monoclinic
Hazards
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-pollu.svg
Danger
H300, H310, H330, H410
P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P304+P340, P310, P320, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
4
0
0
Flash point Non-flammable
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 1 mg/m3 (as Cu) [3]
REL (Recommended)
TWA 1 mg/m3 (as Cu) [3]
IDLH (Immediate danger)
TWA 100 mg/m3 (as Cu) [3]
Safety data sheet (SDS) Oxford MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Copper(I) cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs; impure samples can be green due to the presence of Cu(II) impurities. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of nitriles. [4]

Contents

Structure

Copper cyanide is a coordination polymer. It exists in two polymorphs both of which contain -[Cu-CN]- chains made from linear copper(I) centres linked by cyanide bridges. In the high-temperature polymorph, HT-CuCN, which is isostructural with AgCN, the linear chains pack on a hexagonal lattice and adjacent chains are off set by +/- 1/3 c, Figure 1. [5] In the low-temperature polymorph, LT-CuCN, the chains deviate from linearity and pack into rippled layers which pack in an AB fashion with chains in adjacent layers rotated by 49 °, Figure 2. [6]

LT-CuCN can be converted to HT-CuCN by heating to 563 K in an inert atmosphere. In both polymorphs the copper to carbon and copper to nitrogen bond lengths are ~1.85 Å and bridging cyanide groups show head-to-tail disorder. [7]

Preparation

Cuprous cyanide is commercially available and is supplied as the low-temperature polymorph. It can be prepared by the reduction of copper(II) sulfate with sodium bisulfite at 60 °C, followed by the addition of sodium cyanide to precipitate pure LT-CuCN as a pale yellow powder. [8]

2 CuSO4 + NaHSO3 + H2O + 2 NaCN → 2 CuCN + 3 NaHSO4

On addition of sodium bisulfite the copper sulfate solution turns from blue to green, at which point the sodium cyanide is added. The reaction is performed under mildly acidic conditions. Copper cyanide has historically been prepared by treating copper(II) sulfate with sodium cyanide, in this redox reaction, copper(I) cyanide forms together with cyanogen: [9]

2 CuSO4 + 4 NaCN → 2 CuCN + (CN)2 + 2 Na2SO4

Because this synthetic route produces cyanogen, uses two equivalents of sodium cyanide per equivalent of CuCN made and the resulting copper cyanide is impure it is not the industrial production method. The similarity of this reaction to that between copper sulfate and sodium iodide to form copper(I) iodide is one example of cyanide ions acting as a pseudohalide. It also explains why copper(II) cyanide, Cu(CN)2, has not been synthesised.

Reactions

Copper cyanide is insoluble in water but rapidly dissolves in solutions containing CN− to form [Cu(CN)3]2− and [Cu(CN)4]3−, which exhibit trigonal planar and tetrahedral coordination geometry, respectively. These complexes contrast with those of silver and gold cyanides, which form [M(CN)2]− ions in solution. [10] The coordination polymer KCu(CN)2 contains [Cu(CN)2]− units, which link together forming helical anionic chains. [11]

Copper cyanide is also soluble in concentrated aqueous ammonia, pyridine and N-methylpyrrolidone.

Applications

Cuprous cyanide is used for electroplating copper. [4]

Organic synthesis

CuCN is a prominent reagent in organocopper chemistry. It reacts with organolithium reagents to form "mixed cuprates" with the formulas Li[RCuCN] and Li2[R2CuCN]. The use of CuCN revolutionized the deployment of simpler organocopper reagents of the type CuR and LiCuR2, the so-called Gilman reagents. In the presence of cyanide, these mixed cuprates are more readily purified and more stable.

The mixed cuprates Li[RCuCN] and Li2[R2CuCN] function as sources of the carbanions R−, but with diminished reactivity compared to the parent organolithium reagent. Thus they are useful for conjugate additions and some displacement reactions.

CuCN also forms silyl and stannyl reagents, which are used as sources of R3Si− and R3Sn−. [12]

CuCN is used in the conversion of aryl halides to nitriles in the Rosenmund–von Braun reaction. [13]

CuCN has also been introduced as a mild electrophilic source of nitrile under oxidative conditions, for instance secondary amines [14] as well as sulfides and disulfides [15] have been efficiently cyanated using this methodology. This last methodology has been then introduced in a domino 3 component reaction, leading to 2-aminobenthiazoles. [16]

Related Research Articles

<span class="mw-page-title-main">Cyanide</span> Any molecule with a cyano group (–C≡N)

In chemistry, a cyanide is a chemical compound that contains a C≡N functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.

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

Sodium cyanide is a poisonous compound with the formula NaCN. It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its high reactivity toward metals. It is a moderately strong base.

<span class="mw-page-title-main">Gilman reagent</span> Class of chemical compounds

A Gilman reagent is a lithium and copper (diorganocopper) reagent compound, R2CuLi, where R is an alkyl or aryl. These reagents are useful because, unlike related Grignard reagents and organolithium reagents, they react with organic halides to replace the halide group with an R group (the Corey–House reaction). Such displacement reactions allow for the synthesis of complex products from simple building blocks.

In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.

Cuprate loosely refers to a material that can be viewed as containing anionic copper complexes. Examples include tetrachloridocuprate ([CuCl4]2−), the superconductor YBa2Cu3O7, and the organocuprates (e.g., dimethylcuprate [Cu(CH3)2]−). The term cuprates derives from the Latin word for copper, cuprum. The term is mainly used in three contexts: oxide materials, anionic coordination complexes, and anionic organocopper compounds.

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

Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride (CuCl2).

The Corey–House synthesis is an organic reaction that involves the reaction of a lithium diorganylcuprate with an organic halide or pseudohalide to form a new alkane, as well as an ill-defined organocopper species and lithium (pseudo)halide as byproducts.

The Ullmann condensation or Ullmann-type reaction is the copper-promoted conversion of aryl halides to aryl ethers, aryl thioethers, aryl nitriles, and aryl amines. These reactions are examples of cross-coupling reactions.

<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.

Cyanogen bromide is the inorganic compound with the formula (CN)Br or BrCN. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds. The compound is classified as a pseudohalogen.

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

Silver cyanide is the chemical compound with the formula AgCN. It is a white salt that precipitated upon treatment of solutions containing Ag+ with cyanide, which is used in some schemes to recover silver from solution. Silver cyanide is used in silver-plating.

<span class="mw-page-title-main">Organocopper chemistry</span> Compound with carbon to copper bonds

Organocopper chemistry is the study of the physical properties, reactions, and synthesis of organocopper compounds, which are organometallic compounds containing a carbon to copper chemical bond. They are reagents in organic chemistry.

In organic synthesis, cyanation is the attachment or substitution of a cyanide group on various substrates. Such transformations are high-value because they generate C-C bonds. Furthermore nitriles are versatile functional groups.

Vicinal difunctionalization refers to a chemical reaction involving transformations at two adjacent centers. This transformation can be accomplished in α,β-unsaturated carbonyl compounds via the conjugate addition of a nucleophile to the β-position followed by trapping of the resulting enolate with an electrophile at the α-position. When the nucleophile is an enolate and the electrophile a proton, the reaction is called Michael addition.

Reactions of organocopper reagents involve species containing copper-carbon bonds acting as nucleophiles in the presence of organic electrophiles. Organocopper reagents are now commonly used in organic synthesis as mild, selective nucleophiles for substitution and conjugate addition reactions.

Copper(I) sulfate, also known as cuprous sulfate, is an inorganic compound with the chemical formula Cu2SO4. It is a white solid, in contrast to copper(II) sulfate, which is blue in hydrous form. It is an unusual example of a copper(I) compound derived from an oxyanion, illustrated also by the non- or fleeting existence of cuprous nitrate and cuprous perchlorate.

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">Copper(I) thiocyanate</span> Chemical compound

Copper(I) thiocyanate is a coordination polymer with formula CuSCN. It is an air-stable, white solid used as a precursor for the preparation of other thiocyanate salts.

<span class="mw-page-title-main">Organic thiocyanates</span>

Organic thiocyanates are organic compounds containing the functional group RSCN. the organic group is attached to sulfur: R−S−C≡N has a S–C single bond and a C≡N triple bond.

<span class="mw-page-title-main">Copper compounds</span> Chemical compounds containing copper

Copper forms a rich variety of compounds, usually with oxidation states +1 and +2, which are often called cuprous and cupric, respectively. Copper compounds, whether organic complexes or organometallics, promote or catalyse numerous chemical and biological processes.

References

  1. ↑ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN   0-8493-0487-3.
  2. ↑ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–188. ISBN   978-1138561632.
  3. 1 2 3 NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 H. Wayne Richardson "Copper Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi : 10.1002/14356007.a07_567
  5. ↑ S. J. Hibble; S. M. Cheyne; A. C. Hannon; S. G. Eversfield (2002). "CuCN: A Polymorphic Matirial. Structure of One Form from Total Neutron Diffraction". Inorg. Chem. 41 (20): 8040–8048. doi:10.1021/ic0257569. PMID   12354028.
  6. ↑ S. J. Hibble; S. G. Eversfield; A. R. Cowley; A. M. Chippindale (2004). "Copper(I) Cyanide: A Simple Compound with a complicated Structure and Surprising Room-Temperature Reactivity". Angew. Chem. Int. Ed. 43 (5): 628–630. doi:10.1002/anie.200352844. PMID   14743423.
  7. ↑ S. Kroeker; R. E. Wasylishen; J. V. Hanna (1999). "The Structure of Solid Copper(I) Cyanide: A Multinuclear Magnetic and Quadrupole Resonance Study". Journal of the American Chemical Society. 121 (7): 1582–1590. doi:10.1021/ja983253p.
  8. ↑ H. J. Barber (1943). "Cuprous Cyanide: A Note on its Preparation and Use". J. Chem. Soc. : 79. doi:10.1039/JR9430000079.
  9. ↑ J. V. Supniewski and P. L. Salzberg (1941). "Allyl Cyanide". Organic Syntheses .; Collective Volume, vol. 1, p. 46
  10. ↑ Sharpe, A. G. (1976). The Chemistry of Cyano Complexes of the Transition Metals. Academic Press. p. 265. ISBN   0-12-638450-9.
  11. ↑ Housecroft, Catherine E.; Sharpe, Alan G. (2008) Inorganic Chemistry (3rd ed.), Pearson: Prentice Hall. ISBN 978-0-13-175553-6.
  12. ↑ Dieter, R. K. In Modern Organocopper Chemistry; Krause, N., Ed.; Wiley-VCH: Mörlenback, Germany, 2002; Chapter 3.
  13. ↑ Steven H. Bertz, Edward H. Fairchild, Karl Dieter, "Copper(I) Cyanide" in Encyclopedia of Reagents for Organic Synthesis 2005, John Wiley & Sons. doi : 10.1002/047084289X.rc224.pub2
  14. ↑ Teng, Fan; Yu, Jin-Tao; Jiang, Yan; Yang, Haitao; Cheng, Jiang (2014). "A copper-mediated oxidative N-cyanation reaction". Chemical Communications. 50 (61): 8412–8415. doi:10.1039/c4cc03439b. ISSN   1364-548X. PMID   24948488.
  15. ↑ Castanheiro, Thomas; Gulea, Mihaela; Donnard, Morgan; Suffert, Jean (2014). "Practical Access to Aromatic Thiocyanates by CuCN-Mediated Direct Aerobic Oxidative Cyanation of Thiophenols and Diaryl Disulfides". European Journal of Organic Chemistry. 2014 (35): 7814–7817. doi:10.1002/ejoc.201403279. ISSN   1099-0690. S2CID   98786803.
  16. ↑ Castanheiro, Thomas; Suffert, Jean; Gulea, Mihaela; Donnard, Morgan (2016). "Aerobic Copper-Mediated Domino Three-Component Approach to 2-Aminobenzothiazole Derivatives". Organic Letters. 18 (11): 2588–2591. doi: 10.1021/acs.orglett.6b00967 . ISSN   1523-7060. PMID   27192105.
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