Spin Polarization and Ferromagnetism in Two-Dimensional Sheetlike Cobalt(II) Polymers: [Co(L)2(NCS)2] (L=Pyrimidine or Pyrazine)

Abstract

Intralayer antiferromagnetic and ferromagnetic couplings could be correctly predicted by the spin polarization mechanism for the sheetlike polymers [Co(NCS)2(pyz)2]n and [Co(NCS)2(pym)2]n (structure depicted on the right). These structurally characterized compounds and the monomeric complex [Co(NCS)2(pyd)4], which was synthesized for comparison, were obtained from solutions containing Co(NCS)2 and pyrazine (pyr), pyrimidine (pym), or pyridazine (pyd) in methanol.

Spin-polarization in 1,3,5-trihydroxybenzene-bridged first-row transition metal complexes

“…Lloret et al used pyrimidine for the preparation of a 2D Co II network. The ferromagnetic interactions between the Co II ions through the pyrimidine bridging units over two dimensions lead to a ferromagnet with a Curie temperature T C of 8.2 K [61]. Additionally they could show by using the para-isomer pyrazine 9 that the interactions between the Co II ions are antiferromagnetic.…”

Synthesis, crystal structures and properties of Ni(NCS)2-4-(hydroxymethyl)pyridine coordination compounds

“…However, there are also several compounds reported in literature, in which the metal cations are linked by, e.g., l-1,3-briding anions into coordination polymers. In this case the cations can be linked by pairs of anionic ligands into dimers or chains or can be connected by single anionic ligands into layers [8][9][10][11][12][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Even if for some compounds with terminal N-bonded ligands spin-crossover is observed [5][6][47][48][49][50], the coordination polymers with bridging anionic ligands show a more versatile magnetic behavior [32][33][34][35][36][37][38][39][40].…”

Some Copper and Cobalt Complexes of Schiff-Base Macrocycles Containing Pyridazine Head Units

“…There are still -other than our own cobalt pyridazine complexes [4,5,8,9,11] -only four other crystallographically characterised cobalt complexes containing a CoϪN(pyridazine moiety) bond. [49,83,91,92] The first structurally characterised example was a red-brown high-spin phthalazine-bridged [49] Haupt and coworkers then reported two structurally characterised com- [91] and a monocobalt() complex, [Co 0 {η 2 -benzo[c]cinnoline-N,NЈ}tris(trimethylphosphane)]. [92] Finally, an orange highspin monocobalt() complex [Co II (pyridazine) 4 …”