Structural, Spectroscopic, and Magnetic Characterization of the Coordination Polymers [M^II(NCS)₂(bpe)₂]·3H₂O·2C₂H₆SO [M = Co, Ni; bpe = 1,2-Bis(4-pyridyl)ethylene]. Two Interpenetrated Porous Networks

Abstract

Two novel coordination polymers are obtained by the reaction of M(NO3)2·6H2O (M = CoII, NiII) with KNCS and bpe (bpe = 1,2-bis(4-pyridyl)ethylene). Both compounds, [CoII(NCS)2(bpe)2]·3H2O·2C2H6SO (1) and [NiII(NCS)2(bpe)2]·3H2O·2C2H6SO (2), exhibit the same structure, consisting of two mutually interpenetrated networks made of parallel sheets. The effect of perpendicular concatenation results in fully interlocked networks, which makes the structure define large channels of square geometry. These channels spread along the z-axis, where solvent molecules are located and stack in columns. A compressed octahedral environment, with four bridging bpe ligands occupying the equatorial sites and two terminal N-bonded thiocyanate groups occupying the axial ones, is observed for each metal ion. The magnetic susceptibility measurements show an antiferromagnetic behavior with interactions of low order as a consequence of such a long distance between the metal ions bridged through the bpe ligand. This type of porous covalent boneframe has enclathrated solvent molecules.