Copper nitrate reoxidant

Aryltin compounds react with copper(II) nitrate to give, via the intermediate arylcop-per(II) compounds, the corresponding biaryls (equation 7-21).63 Rather better yields have been obtained with Pd(OAc>2 as the catalyst and CuCF which acts as the reoxidant for the catalyst (equation 7-22).67... 

Experience led to the introduction of catalysts based on nickel nitrate and oxalate, followed by lactate or formate as well as the original carbonates, all supported on infusorial earth, pmnice, or even charcoal to increase activity. Reduction procedures were foimd to be important in obtaining the highest catalyst activity. Reoxidation of nickel before use had to be avoided. Mixed nickel oxide and copper oxide reduced more easily than nickel oxide alone. ... 

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