Cuprous fluoride

Coppers second oxidation state (+2) forms cupric compounds, also referred to as copper(II), which are more stable than copper(l) compounds. For example, copper in both oxidation states can combine with fluorine for copper(I) or cuprous fluoride, Cu" " + F CuF and for copper(ll) or cupric fluoride, Cu " " + 2F —> CuF. ... 

Copper(II) fluoride loses fluorine as it melts. At 950°C it converts to cop-per(I) fluoride (cuprous fluoride), CuF ... 

Cuprous fluoride, CuF.—The fluoride has been prepared by the interaction of hydrogen fluoride and cuprous chloride, and also by the dissociation of cupric fluoride, both processes taking place at a high temperature.9 The product of the action of hydrogen-fluoride solution bn cuprous oxide10 appears to be impure copper only.11 The fluoride is a ruby-red solid. 

Francis SG, Matthews SL, Poleshchuk OK, Walker NR, Legon AC. N2-CU-F a complex of dinitrogen and cuprous fluoride characterized by rotational spectroscopy. Angew Chem Int Ed. 2006 45 6341-6343. 

Although both cuprous and cupric fluorides have been studied in the past, an active fluorine donor can be formed from cupric oxide and hydrogen fluonde. This donor, in combination with 2,2 -bipyridine, effectively displaces the halogen of... 

The Sandmeyer reaction cannot be applied to fluorides (see Secs. 8.6 and 10.4) and the cuprous catalyst is not necessary for the synthesis of aryl iodides for reasons given in Sections 8.6 and 10.6. 

Treatment of diazonium salts with cuprous chloride or bromide leads to aryl chlorides or bromides, respectively. In either case the reaction is called the Sandmeyer reaction The reaction can also be carried out with copper and HBr or HCl, in which case it is called the Gatterman reaction (not to be confused with 11-16). The Sandmeyer reaction is not useful for the preparation of fluorides or iodides, but for bromides and chlorides it is of wide scope and is probably the best way of introducing bromine or chlorine into an aromatic ring. The yields are usually high. 

It has been stated that many halogen-free compounds, e.g., certain derivatives of pyridine and quinoline, purines, acid amides and cyano compounds, when ignited on copper oxide impart a green colour to the flame, presmnably owing to the formation of volatile cuprous cyanide. The test is therefore not always trustworthy. The test is not given by fluorides. 

Kotschy et al. also reported a palladium/charcoal-catalyzed Sono-gashira reaction in aqueous media. In the presence of Pd/C, Cul, PPI13, and z -Pr2NH base, terminal alkynes smoothly reacted with aryl bromides or chlorides, such as 2-pyridyl chloride, 4-methylphenyl bromide, and so on, to give the expected alkyne products in dimethyl-acetamide (DMA)-H20 solvent. Wang et al. reported an efficient cross-coupling of terminal alkynes with aromatic iodides or bromides in the presence of palladium/charcoal, potassium fluoride, cuprous iodide, and triph-enylphosphine in aqueous media (THF/H20, v/v, 3/1) at 60°C.35 The palladium powder is easily recovered and is effective for six consecutive runs with no significant loss of catalytic activity. 

A rapid MW-assisted palladium-catalyzed coupling of heteroaryl and aryl boronic acids with iodo- and bromo-substituted benzoic acids, anchored on TentaGel has been achieved [174]. An environmentally friendly Suzuki cross-coupling reaction has been developed that uses polyethylene glycol (PEG) as the reaction medium and palladium chloride as a catalyst [175]. A solventless Suzuki coupling has also been reported on palladium-doped alumina in the presence of potassium fluoride as a base [176], This approach has been extended to Sonogashira coupling reaction wherein terminal alkynes couple readily with aryl or alkenyl iodides on palladium-doped alumina in the presence of triphenylphosphine and cuprous iodide (Scheme 6.52) [177]. 

Cupredoxin fold , 47 95 Cupric fluoride, stereochemistry, 2 20 Cupric ion, exchange with cuprous ion, NMR of, 4 276-277... 

Cuprous-catalyzed replacement reactions are called Sandmeyer reactions aryl chlorides, bromides, cyanides, and nitro compounds are prepared in this way formation of aryl iodides requires no catalyst, fluorides are obtained by heating diazonium fluoroborates (i.e., Schiemann reaction) benzenols are obtained by warming aqueous diazonium salt solutions. 

An important general method for preparing indoles involves the catalytic elimination of ammonia from phenylhydrazones of carbonyl compounds having an a-roethylene group. Catalysts include zinc chloride, cuprous chloride, boron fluoride etherate, dilute sulfuric acid, alcoholic hydrochloric acid, and glacial acetic acid. ... 

CuCl + 1 cuprous chloride SnFj +2 stannous fluoride... 

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