New mix-ligand copper(i) and copper(ii) pyrazolate complexes with 2,2′-bipyridine

The reaction of the trinuclear copper(i) 3,5-bis(trifluoromethyl) pyrazolate with 2,2′-bipyridine on contact with air leads to the oxidation of Cu centers and affords trinuclear Cuⁱⁱ complex containing bridged pyrazolate OH anions and chelating bipy ligands. Carrying out the reaction in the presence of dppm prevents oxidation and gives dinuclear copper(i) complex with bridging dppm and pyrazolate ligands, and chelating bipy ligand. This complex exhibits red-orange phosphorescence originating from the ³ML^bipyCT state.