Synthesis, structural determination and magnetic properties of three new di-μ1,3-azido copper(II) dimers derived from tridentate amines: magneto-structural correlations

Three new copper(II) dinuclear complexes, derived from the μ1,3-azido bridging ligand and tridentate amines, were synthesised and their crystal structures determined by X-ray diffraction methods. [Cu2(μ-N3)2(Me5dien)2](ClO4)2 (1), [Cu2(μ-N3)2(Et5dien)2](ClO4)2 (2), and [Cu2(μ-N3)2(EtMe4dien)2](ClO4)2 (3). Me5dien is 1,1,4,7,7-pentamethyldiethylenetriamine, Et5dien is 1,1,4,7,7-pentaethyldiethylenetriamine and EtMe4dien is 4-ethyl-1,1,7,7-tetramethyldiethylenetriamine. The three new dinuclear compounds are asymmetrical double bridging μ2-1,3 azido pentacoordinate copper(II) compounds. Variable temperature magnetic susceptibility data showed antiferromagnetic coupling for all of them. These data were fitted to the appropriate equation derived from the Hamiltonian H=−JS1S2 giving the parameters J=−7.5(6) cm−1, g=2.048(14) for 1; J=−28(3) cm−1, g=2.09(8) for 2; and J=−3.6(4) cm−1, g=2.062(8) for 3.