Self-penetration -: A structural compromise between single networks and interpenetration:: Magnetic properties and crystal structures of [Mn(dca)2-(H2O)] and [M(dca)(tcm)], M = Co, Ni, Cu, dca = dicyanamide, N(CN)2-, tcm = tricyanomethanide, C(CN)3-

The three-dimensional coordination polymers [Mn(dca)(2)(H2O)] (1) and [M(dca)(tcm)], M = Co (2), Ni (3), Cu (4), dca=dicyanamide, N(CN)(2)(-), tcm = tricyanomethanide, C(CN)(3)(-), have isomorphous structures. In 1 half the dca ligands coordinate directly (through all three nitrogen atoms) to three Mn atoms (all metal atoms are six-coordinate), while the other half coordinate to two Mn atoms (through the nitrile nitrogens) and hydrogen bond to water molecules coordinated to a third Mn atom (through the amide nitrogen). This dca . H2O structural moiety is disordered over a mirror plane, and is replaced by the structurally equivalent tcm ligand in compounds 2-4. The resulting structures display a new self-penetrating 3,6-connected (2:1) network topology that can be related to, but is different from, the rutile net. The self-penetrating [M(dca)(tcm)] network can be viewed as a structural compromise between the two interpenetrating rutile-like networks of [M(tcm)(2)] and the single rutile-like network of alpha-[M(dca)(2)]. The temperature and field dependence of the BC and AC magnetic susceptibilities and magnetisations has been measured for complexes 1-4. Compounds 1-3 exhibit long-range magnetic order with critical temperatures of 6.3 K for 1, 3.5 K for 2 and 8.0 K for 3. The Cu-II compound 4 does not order and is essentially a paramagnet. Hysteresis measurements of coercive field and remnant magnetisation show that 1, 2 and 3 are soft magnets, 1 being a canted-spin antiferromagnet (weak ferromagnet), while 2 and 3 are ferromagnets that display some unusual features in their high-field magnetisation isotherms in comparison to their related alpha-[M(dca)(2)] phases.