Extended networks of Co2+ and Mn2+ bridged by NCS-/N3- anions and flexible long spacers:: Syntheses, structures, and magnetic properties

Four new metal-organic polymers with SCN-/N-3(-) anion bridges and flexible long spacers L (L = bim [1,2-bis{imidazol-lyl)ethane]} and bte [ 1,2-bis(l, 2,4-triazol-1-yl) ethane]), [Co(SCN)(2)(bim)] (1-Co), [Co(SCN)(2)(bte)] (2-Co), [Mn(N-3)(2)(bte)] (3-Mn), and [Mn(N-3)(2)(bim)] (4-Mn), were synthesized and characterized by single-crystal X-ray diffraction studies and their magnetic properties were investigated. Complex 1-Co is a triple-bridging chain complex with double end-to-end SCN- anions and single gauche-bim spacers as bridges. Complexes 2-Co and 3-Mn both contain 1D chains bridged by double end-to-end SCN- or N3 anions and these chains are further extended to 2D (4,4) layers by the anti-bte spacers. Complex 4-Mn has a topological 3D diamond structure constructed through 1D double end-on azide-bridged Mn-II chains and extended through the anti-bim spacers. Magnetic measurements reveal that 1-Co and 3-Mn remain paramagnetic; the dominant magnetic coupling between Con is weak ferromagnetic and that between Mull is strong antiferromagnetic. As for 2-Co and 4-Mn, they show metamagnetic behavior below T-N = 2.9 and 3.0 K, respectively. Our results show that a combination of the short anion bridges (SCN/ N3) and flexible bidentate long spacers can be used to construct coordination polymers with novel topologies and interesting magnetic properties.