Английская Википедия:Copper(I) bromide

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Copper(I) bromide is the chemical compound with the formula CuBr. This diamagnetic solid adopts a polymeric structure akin to that for zinc sulfide. The compound is widely used in the synthesis of organic compounds and as a lasing medium in copper bromide lasers.

Preparation, basic properties, structure

The compound is white, although samples are often colored due to the presence of copper(II) impurities.[1] The copper(I) ion also oxidizes easily in air. It is commonly prepared by the reduction of cupric salts with sulfite in the presence of bromide.[2] For example, the reduction of copper(II) bromide with sulfite yields copper(I) bromide and hydrogen bromide:

2 CuBr2 + H2O + Шаблон:Chem → 2 CuBr + Шаблон:Chem + 2 HBr

CuBr is insoluble in most solvents due to its polymeric structure, which features four-coordinated, tetrahedral Cu centers interconnected by bromide ligands (ZnS structure). Upon treatment with Lewis bases, CuBr converts to molecular adducts. For example, with dimethyl sulfide, the colorless complex is formed:[3]

CuBr + S(CH3)2 → CuBr(S(CH3)2)

In this coordination complex, the copper is two-coordinate, with a linear geometry. Other soft ligands afford related complexes. For example, triphenylphosphine gives CuBr(P(C6H5)3), although this species has a more complex structure. Thermal excitation of copper(I) bromide vapour yields a blue-violet emission which is of greater saturation than known copper(I) chloride emission.[4] Copper(I) bromide is hence an advantageous emitter in pyrotechnic flames.

Applications in organic chemistry

In the Sandmeyer reaction, CuBr is employed to convert diazonium salts into the corresponding aryl bromides:[2]

Шаблон:Chem + CuBr → ArBr + N2 + Cu+

The aforementioned complex CuBr(S(CH3)2) is widely used to generate organocopper reagents.[3] Related CuBr complexes are catalysts for atom transfer radical polymerization and copper-catalyzed cross-dehydrogenative couplings (CDC).

See also

Copper(II) bromide

References

Шаблон:Reflist

External links

Шаблон:Commons category

Шаблон:Copper compounds Шаблон:Bromides

  1. Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. Шаблон:ISBN.
  2. 2,0 2,1 This report gives a procedure for generating CuBr: Шаблон:OrgSynth
  3. 3,0 3,1 Шаблон:OrgSynth
  4. Шаблон:Cite journal