Formation of the unusual cluster Cu4(μ4-OH)(μ-(CF3)2pz)4(μ-OOCPh)2(μ-OH)2(OH2)(Et3NH)[O(CH2Ph)2]2 in the thermolysis of a copper μ-aqua complex with bridging pyrazolate and acetate ligands in dibenzyl ether in the presence of atmospheric oxygen

A room-temperature reaction of cupric acetate dihydrate with 3,5-bis(trifluoromethyl)pyrazole ((CF3)2pzH) in chloroform in the presence of triethylamine gave a complex of the formula [Cu2(μ-(CF3)2pz)2(μ-OH2)(OC(Me)OHNEt3)(OH2)(HCCl3)(OOCMe)(μ-OOCMe)]2 (2). Heating of this complex at 180°C in dibenzyl ether (DBE) in air yielded the tetranuclear pyrazolate-benzoate cluster Cu4(μ4-OH)(μ-(CF3)2pz)4(μ-OOCPh)2(μ-OH)2(OH2)(Et3NH)[O(CH2Ph)2]2. It was suggested that such complexes can be intermediates in the liquid-phase oxidation of DBE with atmospheric oxygen in the presence of copper complexes containing pyrazolate bridges.