Versatility of the cyanato ligand:: structure and magnetic properties of four new copper(II)-cyanato compounds derived from tridentate amines

Four new copper(II) complexes, derived from the cyanato ligand and tridentate amines, with different nuclearity and different coordination modes, have been synthesized and their crystal structures determined by X-ray diffraction methods: [Cu(NCO)(Et(5)dien)](ClO4) (1), mononuclear, [Cu-2(mu(1,3)-NCO)(2)(EtMe(4)dien)(2)](ClO4)(2) (2), dinuclear, [Cu(mu-ClO4)(NCO)(ept)](n) (3), monodimensional, and [Cu-2(mu(1,1)-NCO)(2)(Medien)(2)](ClO4)(2) (4), dinuclear. Et(5)dien is 1,1,4,7,7-pentaethyldiethylenetriamine, EtMe(4)dien is 4-ethyl-1,1,7,7-tetramethyldiethylenetriamine, ept is N-(2-aminoethyl)-1,3-propanediamine and Medien is 4-methyldiethylenetriamine. Magnetic susceptibility data, measured from 2-300 K, show slight ferromagnetic coupling for the dinuclear end-to-end (mu(1,3)) compound 2, antiferromagnetic coupling for the dinuclear end-on (mu(1,1)) 4, and antiferromagnetic coupling for the mu-ClO4, monodimensional compound 3. These data were fitted to the appropriate equations derived from the Hamiltonian H = -JS(1)S(2) giving the parameters J = +0.5(2) cm(-1), g = 2.088(3) and J = -4.6(3) cm(-1), g = 2.099(13) for 2 and 4, respectively and J = -1.9(1) cm (-1), g = 2.121(7) for 3. (C) 1999 Elsevier Science S.A. All rights reserved.