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

Three 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 · 2 n CH 3 OH ( 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 μ 1,5 ‐dca bridges. Whereas compound 3 is a two‐dimensional coordination layer in which the metal atoms are linked by single μ 1,5 ‐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 CONH 2 group to create a 2D supramolecular layer. For 2 , the N–H ··· O, O–H ··· O hydrogen‐bonding interactions between CH 3 OH molecules and CONH 2 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 CONH 2 groups, N–H ··· N interactions from CONH 2 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.