Copper(I) Bromide

[7787-70-4] BrCu (MW 143.45) InChI = 1/BrH.Cu/h1H;/q;+1/p-1/fBr.Cu/h1h;/q-1;m InChIKey = NKNDPYCGAZPOFS-ZFYMQJCYCJ CuBr·SMe2 [54678-23-8] C2H6BrCuS (MW 205.59) InChI = 1/C2H6S.BrH.Cu/c1-3-2;;/h1-2H3;1H;/q;;+1/p-1/fC2H6S.Br.Cu/h;1h;/q;-1;m InChIKey = PMHQVHHXPFUNSP-GUDWEBAYCB (precursor for organocopper(I) reagents and organocuprates;1a–f catalyst for diazo chemistry) Alternate Name: cuprous bromide. Physical Data: mp 504 °C; the complex with dimethyl sulfide (DMS) decomposes at ca. 130 °C; d 4.720 g cm−3. Solubility: insoluble in H2O and most organic solvents; partially soluble in dimethyl sulfide. Form Supplied in: light green or blue-tinged white solid. 99.999% grade available. The DMS complex is a white solid. Preparative Methods: commercial copper bromide is often contaminated; the use of freshly prepared or purified copper bromide is strongly advised. Copper bromide can be prepared by reduction of CuBr238 or CuSO4–NaBr.39 Purity: the colored impurities in the title reagent can be removed from the commercial samples by dissolving an appropriate quantity of CuBr in a saturated aqueous solution of KBr over 30 min. Subsequent cooling, treating with charcoal, filtering, and diluting with water allows for the formation of the CuBr precipitate.40 Traces of iron salts can be removed via the sulfide complex.41 Alternatively, copper bromide can be purified by precipitation from 48% HBr. The precipitate is filtered and washed sequentially with water, ethanol, and ether, then finally dried under vacuum.42 Handling, Storage, and Precautions: maintenance of a dry N2 or Ar atmosphere is recommended. The DMS complex must be tightly sealed to prevent loss of DMS. Storage of this complex in a cold place is recommended.