Copper(I) bromide is the
chemical compound with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
CuBr. This
diamagnetic solid adopts a polymeric structure akin to that for
zinc sulfide. The compound is widely used in the
synthesis
Synthesis or synthesize may refer to:
Science Chemistry and biochemistry
*Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors
** Organic synthesis, the chemical synthesis of organ ...
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. The copper(I) ion also oxidizes easily in air. It is commonly prepared by the reduction of cupric salts with
sulfite
Sulfites or sulphites are compounds that contain the sulfite ion (or the sulfate(IV) ion, from its correct systematic name), . The sulfite ion is the conjugate base of bisulfite. Although its acid ( sulfurous acid) is elusive, its salts are wide ...
in the presence of bromide.
[This report gives a procedure for generating CuBr: ] For example, the reduction of
copper(II) bromide with sulfite yields copper(I) bromide and
hydrogen bromide:
:2 CuBr
2 + H
2O + → 2 CuBr + + 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 base
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...
s, CuBr converts to molecular
adducts. For example, with
dimethyl sulfide
Dimethyl sulfide (DMS) or methylthiomethane is an organosulfur compound with the formula (CH3)2S. Dimethyl sulfide is a flammable liquid that boils at and has a characteristic disagreeable odor. It is a component of the smell produced from cook ...
, the colorless complex is formed:
:CuBr + S(CH
3)
2 → CuBr(S(CH
3)
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(C
6H
5)
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.
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:
[
: + CuBr → ArBr + N2 + Cu+
The aforementioned complex CuBr(S(CH3)2) is widely used to generate organocopper reagents.][ Related CuBr complexes are catalysts for ]atom transfer radical polymerization Atom transfer radical polymerization (ATRP) is an example of a reversible-deactivation radical polymerization. Like its counterpart, ATRA, or atom transfer radical addition, ATRP is a means of forming a carbon-carbon bond with a transition metal cat ...
and copper-catalyzed cross-dehydrogenative couplings (CDC).
References
External links
Web Elements
{{bromides
Bromides
Metal halides
Copper(I) compounds
Zincblende crystal structure