Synthesis and characterisation of phenoxo bridged dinuclear complexes of copper (II)

摘要

A series of model complexes for the type III site, in oxidised hemocyanin, containing Cu_2(mu-OPh)~(3+) core have been synthesised using a heptadentate ligand (H_3L) formed from the Schiff base condensation of triethylenetetramine and sahcylaldehyde.The ligand provides one imine and one inbuilt imidazole nitrogen and two phenolic oxygen donors with both five-and six-membered chelate rings to each metal centre. In the pentacoordinated complexes [Cu_2(L)X].nH_2O, a third exogenous bridging ligand is present. The TG curve indicates the loss of lattice water molecules between 70 and 125°C. The residue after decomposition is CuO above 550°C. The g values of the X-band EPR spectrum of [Cu_2L(mu-OAc)] .2H_2O in methanol glass (77 K) are typical of a variety of bridged copper(II) dimers. The copper-copper magnetic interaction is dependent on the presence and nature of X in these complexes.