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−

Abstract

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 DC 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 Cu11 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.

cis-Bis(dicyanamido)bis(1,10-phenanthroline)cadmium(II)

“…Investigation of metal-dca complexes {dca is dicyanamide, [N(CN) 2 ] À } is a fast-growing research field because of the large variety of topologies and magnetic properties shown by complexes of the dca ligand (Miller & Manson, 2001;Batten & Murray, 2003). It is a versatile ligand coordinating to metal ions in various modes: monodentate binding through one nitrile N atom (Marshall et al, 2000), end-to-end bridging through the two nitrile N atoms Jensen et al, 1999) and triply bridging three metal atoms using all three N donor atoms (Jensen et al, 2000;Kurmco & Kepert, 1998). These varied coordination possibilities allow the preparation of compounds with a variety of architectures, including mono-and dinuclear complexes, as well as one-, twoand three-dimensional network structures.…”

A one-dimensional copper coordination polymer containing both dicyanamide and 1,10-phenanthroline ligands

“…In a separate area, metal dicyanamide {dca, [N(CN) 2 ] À } coordination chemistry is a fast-growing research ®eld because of the interesting possibilities for coordination and physical properties that these complexes possess (Miller & Manson, 2001). Dicyanamide is a versatile ligand for coordinating to metal ions in various modes, such as monodentate bonding through a nitrile N atom (Marshall et al, 2000), end-to-end bridging through the two nitrile N atoms Jensen et al, 1999) and triply coordinating through its three N atoms, bridging three metal atoms (Jensen et al, 2000;Kurmco & Kepert, 1998). The coordination properties thus allow for the preparation of compounds with a large variety of architectures, both mononuclear and dinuclear, as well as one-, two-and three-dimensional networks.…”

Crystal Engineering of Mixed-Metal Ru–Ag Coordination Networks by Using the trans-[RuCl2(pyz)4] (pyz=pyrazine) Building Block This work was supported by MURST within the project “Solid Supermolecules” 2000–2001 and by CSMTBO-CNR Center.

“…The topology of this network, based on six‐ and three‐connected nodes in the ratio 1:2, is the same of the prototypical rutile,12, 14 with Ru in the place of Ti and Ag in the place of O (see Figure 3, bottom left). Few other examples of coordination networks with this topology have been previously reported 16. The channels along [1 0 1] (Figure 3, top) contain solvated molecules of TCE and butanol (that are lost on heating the bulk samples above 120 °C).…”