Complexes of Cu2(μ‐OAc)4(H2O)2 with 1,10‐phenanthroline and Comparison with Those of 2,2′‐bipyridine. Crystal Structure of the Dimer [Cu(oac)2(phen)](μ‐h2o)

The two complexes of composition Cu-2(OAC)(4)(phen)(H2O)(2) (1) and Cu-2(OAC)(4)(phen)(2)(H2O) (2) have been synthesized and characterized by chemical analysis and IR and electronic spectroscopies. Compound 2 has the structure of a dimer with a phenanthroline molecule and two monodentate acetate groups coordinated to each copper atom and a water molecule as the only bridging ligand between them. Each copper atom has a distorted square-planar pyramidal coordination, determined by two oxygen atoms at 1.94(3) and 1.959(3)angstrom, two nitrogen atoms at 2.023(4) angstrom and the oxygen atom of the bridging water molecule at 2.289(2) angstrom. The distance between the two copper atoms is of 4.29 angstrom and the angle Cu(l)-O(3)-Cu(1A) 139.2(2)degrees. The water molecule is involved in two intramolecular hydrogen bonds with non coordinated oxy-gen atoms. The distance between the molecules of phenanthroline is 3.75 angstrom. Magnetic and EPR results for Cu-2(OAC)(4)(phen)(H2O)(2) (I),Cu-2(OAC)(4)(phen)(2)(H2O) (2), Cu-2(OAC)(4)(bipy) (3) and Cu-2(OAC)(4)(bipy)(2)(H2O)(2) (4) have been analysed and compared. For 1 and 3 an antiferromagnetic dimer unit [Cu-2(mu-OAc)(4)] with 2J = -325 and -292cm(-1), respectively, and other two copper atoms without significant magnetic interaction are present. Triplet signals are detected in the EPR spectra. In 2 and 4 there is no practically magnetic exchange and the orthorhombic signals are observed in the EPR spectra.