Diamond- and graphite-like octacyanometalate-based polymers induced by metal ions

By using cyclohexane-1,2-diamine (chxn), Ni(ClO(4))(2) x 6 H(2)O and Na(3)[Mo(CN)(8)] x 4 H(2)O, a 3D diamond-like polymer {[Ni(II)(chxn)(2)](2)[Mo(IV)(CN)(8)] x 8 H(2)O}(n) (1) was synthesised, whereas the reaction of chxn and Cu(ClO(4))(2) x 6 H(2)O with Na(3)[M(V)(CN)(8)] x 4 H(2)O (M = Mo, W) afforded two isomorphous graphite-like complexes {[Cu(II)(chxn)(2)](3)[Mo(V)(CN)(8)](2) x 2 H(2)O}(n) (2) and {[Cu(II)(chxn)(2)](3)[W(V)(CN)(8)](2) x 2 H(2)O}(n) (3). When the same synthetic procedure was employed, but replacing Na(3)[Mo(CN)(8)] x 4 H(2)O by (Bu(3)NH)(3)[Mo(CN)(8)] x 4 H(2)O (Bu(3)N = tributylamine), {[Cu(II)(chxn)(2)Mo(IV)(CN)(8)][Cu(II)(chxn)(2)] x 2 H(2)O}(n) (4) was obtained. Single-crystal X-ray diffraction analyses showed that the framework of 4 is similar to 2 and 3, except that a discrete [Cu(chxn)(2)](2+) moiety in 4 possesses large channels of parallel adjacent layers. The experimental results showed that in this system, the diamond- or graphite-like framework was strongly influenced by the inducement of metal ions. The magnetic properties illustrate that the diamagnetic [Mo(IV)(CN)(8)] bridges mediate very weak antiferromagnetic coupling between the Ni(II) ions in 1, but lead to the paramagnetic behaviour in 4 because [Mo(IV)(CN)(8)] weakly coordinates to the Cu(II) ions. The magnetic investigations of 2 and 3 indicate the presence of ferromagnetic coupling between the Cu(II) and W(V)/Mo(V) ions, and the more diffuse 5d orbitals lead to a stronger magnetic coupling interaction between the W(V) and Cu(II) ions than between the Mo(V) and Cu(II) ions.