Crystal structure, magnetic properties and orbital interactions of the binuclear fumarato-bridged bis[(( N-(2-diethylamino)ethyl)-salicylidenaminato)copper( II)] complex

Abstract

The title compound of formula [Cu 2(SalNEt 2) 2(C 4H 2O 4)], where SalNEt 2= N-(2-(diethylamino)ethyl)- salicylidenaminate, has been synthesized and its structure solved at room temperature. It crystallizes in the monoclinic system, space group P2 1/ c, with a=10.463(2), b=16.048(2), c=9.434(1) Å, β=106.91(1)° and Z=2. In the molecular structure of this centrosymmetric compound the two equivalent copper( II) ions are bridged by the fumarato ligand coordinated in an amphimonodentate mode. The local geometry around both copper( II) ions is approximately 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 ( Ĥ=−2 JŜ 1 Ŝ 2), S 1= S 2=1/2 spin exchange model, yields a 2 J value of −1.8 cm −1. An orbital interpretation of the observed weak antiferromagnetic interactions is presented based on the results of extended Hückel calculations on a model compound.