Syntheses, Crystal Structures and Magnetism of Three Metal–Dicyanamide Coordination Polymers with Isonicotinamide Co‐Ligand

Abstract

AbstractThree metal–dicyanamide (dca) coordination polymers combined with isonicotinamide (4‐nic) terminal co‐ligand, namely, [Mn(dca)2(4‐nic)2]n (1), [Co(dca)2(4‐nic)2]n·2nCH3OH (2) and [Mn(dca)2(4‐nic)2]n (3) were synthesized at room temperature. X‐ray single crystal diffraction reveals that complexes 1 and 2 have similar one‐dimensional metal–dca coordination chains in which the octahedral metal atoms are connected by double μ1,5‐dca bridges. Whereas compound 3 is a two‐dimensional coordination layer in which the metal atoms are linked by single μ1,5‐dca bridge. The coordination chains of 1 and 2 are further cross‐linked by N–H···N hydrogen bonding interactions between the uncoordinated nitrogen atom of dca and a hydrogen atom from the CONH2 group to create a 2D supramolecular layer. For 2, the N–H···O, O–H···O hydrogen‐bonding interactions between CH3OH molecules and CONH2 groups extend the 2D layers into a three‐dimensional network. The 2D layers of 3 are further connected by N–H···O, C–H···O hydrogen bonds between CONH2 groups, N–H···N interactions from CONH2 groups and a nitrile nitrogen atom of dca to give a 3D supramolecular architecture. Magnetic studies reveal that weak antiferromagnetic exchanges exist between the metal atoms in 2 and 3 (J = –0.27 cm–1, g = 1.99). The thermal stability of 2 is also discussed.