A highly efficient CuBr

• click to rate

  Posted by Alex myx Sep 22 - Filed in Technology - #CuBr  - 31 views
  

  With i-Pr2S, the octanuclear cluster [(i-Pr2S)6{Cu8(μ3-I)3}(μ4-I)2}]is formed. An X-ray study has also been performed at five different temperatures for the 2D polymer [(Cu3Br3)(MeSEt)3]n (9) formed from the reaction between CuBr and MeSEt in heptane. The unprecedented framework of 9 consists of layers with alternating Cu(μ2-Br)2Cu rhomboids, which are connected through two μ-MeSEt ligands to tetranuclear open-cubane Cu4Br4 SBUs. MeSPr forms with CuBr in heptane the 1D CP [(Cu3Br3)(MeSPr)3]n (10), which is converted to a 2D metal–organic framework [(Cu5Br5)(μ2-MeSPr)3]n (11) incorporating pentanuclear [(Cu5(μ4-Br)(μ2-Br)] SBUs when recrystallized in MeCN. The thermal stability and photophysical properties of these materials are also reported.
  CuBr was found to be an efficient catalyst for the C–N cross coupling reaction of purine and diaryliodonium salts. 9-Arylpurines were synthesized in excellent yields with short reaction times (2.5 h). The method represents an alternative to the synthesis of 9-arylpurines viaCu(II) catalyzed C–N coupling reaction with arylboronic acids as arylating agents.
  A highly efficient CuBr-catalyzed coupling of ketones, amines and alkynes (KA2) forming propargylic amines bearing a quaternary carbon center with the broadest scope so far has been developed.
  Copperbromide 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.
  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:

  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 copperbromide vapour yields a blue-violet emission which is of greater saturation than known copperchloride emission. Copperbromide is hence an advantageous emitter in pyrotechnic flames.

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

  ArN+
  2 + 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 and copper-catalyzed cross-dehydrogenative couplings (CDC).