Homoleptic pyrazolate complexes

Dinuclear complexes were obtained by reacting some binary copper(I) and silver(I) homoleptic pyrazolate complexes with neutral ligands. The trimeric [Cu(dmpz)]3 (23) readily reacted with phen or RNC (R = cyclohexyl) to give the doubly bridged species [(phen)Cu(/i-dmpz)2Cu(phen)], 32, (49) or [(RNC)Cu(/t-dmpz)2Cu(RNC)], 33 (50). The dimeric nature of 32 was argued from its spectroscopic and chemical properties, while 33 was characterized by an X-ray crystal structure analysis (50). 

Recently, it has been found that the copper(I) homoleptic pyrazolate complexes [Cu(dmpz)], 6, and [Cu(dppz)]4, 8, are catalytically active in the oxidative coupling of primary aromatic amines to give the corresponding azobenzenes in the presence of 02 at atmospheric pressure (17, 137). 

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