Molecular structure and magnetic properties of the binuclear phthalato-bridged species bis[(N-(2-(diethylamino)ethyl)salicyliden-aminato)-copper(II)] trihydrate

The crystal structure of (mu-phthalato)bis[(N-(2-(diethylamino)ethyl)-salicylidenaminato)copper(II)-trihydrate, [Cu-2(salNet(2))(2)(mu-phthal)].3H(2)O, where salNet(2)=N-(2-(diethylamino)-ethyl)salicylidenaminate, has been determined by single-crystal X-ray analysis. It crystallizes in the monoclinic system, space group P2(1)/c, with a=19.9109(9), b=10.0465(4), c=18.5837(8) Angstrom, and beta=100.625(1)degrees. In the molecular structure the two copper(II) ions are bridged by the phthalato ligand coordinated in an amphimonodentate mode and the local geometry around both copper(II) ions is square planar. Magnetic susceptibility data for the complex as a function of temperature show weak exchange interactions. The fitting of these data to the HDVV ((H) over cap= -2J (S) over cap (1) (S) over cap (2)), S-1=S-2=1/2 spin exchange model, yields a 2J value of -0.34 cm(-1). An orbital interpretation of the observed weak antiferromagnetic interactions is presented based on the results of extended Huckel calculations on a model molecule.