A dimeric copper coumarin complex:: synthesis and crystal structure of [{Cu(4-methyl-7-(salicylideneamino)coumarin)2}2]

A binuclear copper complex [{Cu(L)(2)}(2)], C68H48Cu2N4O12C (where L is 4-methyl-7-(salicylideneamino)coumarin), has been synthesized and characterized using elemental analysis, molar conductance measurements, and infrared, ultraviolet and ESR spectrosopy. The molecular structure of title compound, determined by single-crystal X-ray diffraction studies, reveals that the two symmetric Cu(L)(2) units are associated into a dimer by rather long Cu center dot center dot center dot O bonds. The Cu(II) ions are bridged via the phenolic oxygen of one of the monomers and have distorted trigonal bipyramidal conformation geometry. Within each monomer the two methylsubstituted coumarin skeletons are trans to one another, but adopt a parallel arrangement with respect to the other monomer. Only half of the complex molecule can be found in the asymmetric unit, Z' = 0.5, the other half is generated by the symmetry centre.