CuCl, CuBr

The diazonium salts usually decompose when warmed with water to give a phenol and nitrogen. When treated with CuCl, CuBr, KI, the diazo group is replaced by chlorine, bromine or iodine respectively (Sandmeyer reaction). A diazonium sulphate and hydroxyl-amine give an azoimide. The diazonium salt of anthranilic acid (2-aminobenzoic acid) decomposes to give benzyne. ... 

Sandmeyer reaction (Section 22 17) Reaction of an aryl dia zonium ion with CuCl CuBr or CuCN to give respec tively an aryl chloride aryl bromide or aryl cyanide (nitrile)... 

Terminal acetylenes such as phenylacetylene are transformed by Znl2, CuCl, CuBr, or CuCN and BTSP 1949 into 1-iodo- 1976, 1-chloro- 1978, 1-bromo- 1979, or l-cyano-4-phenylaIkynes 1980 and to the diacetylene 1977 [156] (Scheme 12.44). 

This structure is adopted by a large number of III/V semiconductors, including GaAs, InP, and halides, including Agl, CuF, CuCl, CuBr, and Cul. 

Compounds of the I—VII group in the periodic table are known to exhibit good ionic conductivity and have attracted much attention as possible candidates for solid electrolytes. A typical family of compounds is Lil, CuCl, CuBr, and Agl. Historically, polycrystalline solid electrolytes were noticed to show significantly higher ionic conductivity than bulk crystals, since a half century ago. Furthermore, a large increase in conductivity was reported for the system of the mixture of a solid electrolyte such as CuCl (1) and Agl (2) with submicrometer particles of several sorts of insulating materials. In this case, the size of the metal halide itself was on the order of a micrometer or larger. It was also reported that the enhanced conductivity was approximately proportional to the inverse of the size of the electrolyte substances (2). Hence it is natural to make an effort to obtain fine particles of metal halides in order to get better conductivity. 

The wurtzite structure is closely related to the zinc blende structure, having the same 4 4 tetrahedral coordination arising from a hexagonal close packing of anions in which half the tetrahedral sites are occupied by cations. Examples of AB compounds crystallizing in this structure are CuCl, CuBr, Cul, Agl, BeO, ZnO, ZnS, MnS, MnSe,... 

The exchange reaction of 1-bromonaphthalene with CuCl proceeds effectively in polar solvents, such as DMF or DMSO, at temperatures of 110-150 °C via a second-order mechanism. The reaction is reversible but the equilibrium favors formation of aryl chlorides. The catalysis is inhibited by chloride anion and by pyridine or, particularly, 2,2 -bipyri-dine. The ease of replacement decreased in the order Arl> ArBr> ArCl and the reactivity of the attacking nucleophile decreased in the order CuCl> CuBr> Cul. The exchange reac-... 

CuCl (CuBr)-- ArCl (ArBr) + N2 (Sandmeyer reaction)... 

Reaction of a diazonium salt with CuCl, CuBr, HBF4, Nal, or K1 (25.14A)... 

AgF, AgCl and AgBr crystallize with a sodium chloride lattice and CuCl, CuBr, and Cul with the lattice given in Figure 62 in which copper has a coordination number of four. This difference in crystal structure of the two salts is not determined by the difference in the dimensions of the Ag"+ and Cu+ ions, since according to Pauling the latter has the value 0-96 A, which is not outside the limits for a sodium chloride lattice. The decrease of the coordination number from six to four and the formation of a tetrahedral configuration are more probably determined by the covalent character of the bonds between copper and chlorine. However, it is to be emphasized that the bonds are not entirely covalent any more than they are entirely ionic, but are of an intermediate... 

As can be seen in the following examples, both Cu and Cu" salts such as CuCl. CuBr, Cul, CuCN, Cu(acac)2, and Li2CuCl4 (known as Kochi s catalyst [22]), introduced at 0.2 10% to a Grignard or a substrate are most typical for these reactions. The choice of copper salts is dependent on their intrinsic reactivities, as well as on physical properties, such as solubility and ease of handling. For example, Li2CuCl4 is soluble in tetrahydrofuran (THF) and is frequently quite useful to obtain clean cross-coupled products. An added Cu species is considered to be reduced to Cu in situ by the Grignard reagent to participate in the catalytic cycle [see Eq. (36)]. 

Copper salts vary from simple inorganic and organic salts, such as CuCl, CuBr, Cul, and CuBr Mc2S, to more sophisticated ones, which will be discussed in the following text. As described in the previous section, a Cu" species is most likely to be reduced in the reaction medium to a Cu species, which catalyzes the 1,4-addition. This Cu"-Cu issue was revisited recently and, in accord with the foregoing statement, Cu was reconfirmed to be an active catalyst, even though the added copper salt was divalent [160,161],... 

The ambient temperature y phases of CuCl, CuBr, and Cul all possess the cubic... 

Aminothiazole is easily diazotized in a concentrated solution of nitric and phosphoric acid. A large-scale procedure for the diazotization of 2-aminothiazole and its conversion to 2-bromothiazole has been reported . The synthesis of 2-halothiazoles can be easily achieved from 2-aminothiazole by (i) diazotization and (ii) treatment with CuCl, CuBr, or Nal <85JHC1621>. When the diazonium salt derived from 2-aminothiazole is treated with sodium azide the 2-azido derivative in equilibrium with its tetrazole cyclization product are obtained <92BMC1603>. 

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