Synthesis, Structure, and Properties of Coordination Polymers with Layered Transition-Metal Thiocyanato Networks

Reaction of 4-tert-butylpyridine (tBP) with transition-metal thiocyanates leads to the formation of compounds of composition [M(NCS)(2)(tBP)(4)] [M = Mn (1-Mn), Fe (1-Fe), Co (1-Co), Ni (1-Ni)] that consist of discrete complexes, in which the metal centers are octahedrally coordinated by two terminal thiocyanato anions and four tBP ligands. If less tBP is used in the synthesis, two compounds of composition [M(NCS)(2)(tBP)(2)](n) with M = Co (2-Co) and Ni (2-Ni) are obtained, in which the metal centers are linked into a 2D network by single thiocyanato anions. Thermal decomposition of 1-Co leads to the formation of an additional modification of [Co(NCS)(2)(tBP)(2)] (3-Co). Magnetic measurements of 2-Ni and 2-Co reveal that 2-Ni shows a ferromagnetic phase transition at T-c = (14.8 +/- 0.1) K and 2-Co shows a transition to the magnetic state with uncompensated magnetic moment at (3.15 +/- 0.03) K.