Copper complexes fluorides

Copper(ii).—Halides. The complex [CuF(aq)] has been identified in copper(ii)-fluoride solutions. The structure of Cs3Cu2Cl.y,2H20 has been reported and the anion is shown in (184). The salts D2[CuX ] (D = the 2,4-dimethyl-... 

Keywords copper complex, nitroaldol, quaternary ammonium fluoride, zinc complex... 

Copper(I) chloride and bromide are made by boiling an acidic solution of the Cu" salt with an excess of Cu on dilution, white CuCl or pale yellow CuBr is precipitated. Addition of I- to a solution of Cu2+ forms a precipitate that rapidly and quantitatively decomposes to Cul and iodine. Copper(I) fluoride is unknown. The halides have the zinc blende structure (tetrahedrally coordinated Cu+). Cop-per(I) chloride and CuBr are polymeric in the vapor state, and for CuCl the principal species appears to be a six ring of alternating Cu and Cl atoms with Cu—Cl, —2.16 A. White CuCl becomes deep blue at 178°C and melts to a deep green liquid. The halides are very insoluble in water but are solubilized by complex formation... 

Methylation Diazomethane-Boron fluoride etherale. Dimethylcopperlithium. Dimethyl-sulfonium methylide. Iodine Methyl iodide. Methyl-(tri-n-butylphosphine) copper complex. Silver perchlorate. Simmons-Smith reagent. Sodium hydride. 

The complex fluoride CrZrFe (Table 31) is an example of a class of compound A M Fs which undergoes phase transitions as the temperature changes. In the chromium(II) and copper(II) compounds additional modifications occur because of local and cooperative Jahn-Teller distortions. From the three spin-allowed d-d transitions for high-spin Cr in strongly distorted CrFe octahedra (Table 31) an octahedral A value of 7600 cm is calculated. Transitions between the monoclinic IT, pseudotetragonal I and cubic I phases have been... 

While the metal-catalyzed fluorination of benzyl C—H bonds has generated a host of valuable compounds, extending this chenustry to saturated hydrocarbons remains a current and significant challenge. To address this issue, a successful approach for the copper-catalyzed fluorination of unfunctionaUzed hydrocarbons has been devised (Example 7.5) [23, 24]. The catalyst for this reaction was an bisimine copper complex, and Selectfluor was used as an electrophilic source of fluorine. The copper complex was essential for the reaction as no fluorination was observed in its absence. A host of cyclic and acyclic saturated hydrocarbons were successfully fluorinated using this approach, and moderate to good yields of the alkyl fluorides were obtained. For substrates such as ethylbenzene and dihydrocoumarin, fluorination of the benzylic position was preferred. 

Another approach to the conversion of aryltrifluoroborate salts into aryl fluorides also used a common copper salt to promote the reactions however, this chemistry used an electrophilic source of fluorine (Scheme 7.58) [84]. The most effective source of F was found to be A-fluoro-2,4,6-trimethylpyridinium ttiflate. Similar to the authors previous work with arylstannanes, the key to the synthesis was prestirring the F source and the copper complex prior to the introduction of the aryltrifluoroborate salts. Using this system, a wide range of aryltrifluoroborate salts bearing ethers, halogens, aldehydes, ketones, amides, and esters were converted into aryl fluorides. 

Copper III) is known in complex oxides and fluorides and in amino-acid complexes. 

Rubidium metal alloys with the other alkaU metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double haUde salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and 2iac. These complexes are generally water iasoluble and not hygroscopic. The soluble mbidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide. 

Assay of beryUium metal and beryUium compounds is usuaUy accompHshed by titration. The sample is dissolved in sulfuric acid. Solution pH is adjusted to 8.5 using sodium hydroxide. The beryUium hydroxide precipitate is redissolved by addition of excess sodium fluoride. Liberated hydroxide is titrated with sulfuric acid. The beryUium content of the sample is calculated from the titration volume. Standards containing known beryUium concentrations must be analyzed along with the samples, as complexation of beryUium by fluoride is not quantitative. Titration rate and hold times ate critical therefore use of an automatic titrator is recommended. Other fluotide-complexing elements such as aluminum, sUicon, zirconium, hafnium, uranium, thorium, and rate earth elements must be absent, or must be corrected for if present in smaU amounts. Copper-beryUium and nickel—beryUium aUoys can be analyzed by titration if the beryUium is first separated from copper, nickel, and cobalt by ammonium hydroxide precipitation (15,16). 

Precipitation is often applied to the removal of most metals from wastewater including zinc, cadmium, chromium, copper, fluoride, lead, manganese, and mercury. Also, certain anionic species can be removed by precipitation, such as phosphate, sulfate, and fluoride. Note that in some cases, organic compounds may form organometallic complexes with metals, which could inhibit precipitation. Cyanide and other ions in the wastewater may also complex with metals, making treatment by precipitation less efficient. A cutaway view of a rapid sand filter that is most often used in a municipal treatment plant is illustrated in Figure 4. The design features of this filter have been relied upon for more than 60 years in municipal applications. 

The cobalt complex is usually formed in a hot acetate-acetic acid medium. After the formation of the cobalt colour, hydrochloric acid or nitric acid is added to decompose the complexes of most of the other heavy metals present. Iron, copper, cerium(IV), chromium(III and VI), nickel, vanadyl vanadium, and copper interfere when present in appreciable quantities. Excess of the reagent minimises the interference of iron(II) iron(III) can be removed by diethyl ether extraction from a hydrochloric acid solution. Most of the interferences can be eliminated by treatment with potassium bromate, followed by the addition of an alkali fluoride. Cobalt may also be isolated by dithizone extraction from a basic medium after copper has been removed (if necessary) from acidic solution. An alumina column may also be used to adsorb the cobalt nitroso-R-chelate anion in the presence of perchloric acid, the other elements are eluted with warm 1M nitric acid, and finally the cobalt complex with 1M sulphuric acid, and the absorbance measured at 500 nm. 

Sulphuric acid is not recommended, because sulphate ions have a certain tendency to form complexes with iron(III) ions. Silver, copper, nickel, cobalt, titanium, uranium, molybdenum, mercury (>lgL-1), zinc, cadmium, and bismuth interfere. Mercury(I) and tin(II) salts, if present, should be converted into the mercury(II) and tin(IV) salts, otherwise the colour is destroyed. Phosphates, arsenates, fluorides, oxalates, and tartrates interfere, since they form fairly stable complexes with iron(III) ions the influence of phosphates and arsenates is reduced by the presence of a comparatively high concentration of acid. 

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