Structural analysis and magnetic properties of the 1-D compounds [M(NCS)2bpa2] [M = Fe, Co, Ni and bpa = 1,2-bis(4-pyridyl)ethane]

The increasing interest in designing polymeric compounds has focused this work on the synthesis and magnetostructural characterization of three 1-D compounds of general formula [M(NCS)2bpa2] [M = Fe, Co, Ni and bpa = 1,2-bis(4-pyridyl)ethane] which exhibit double bpa bridges between metallic cations. X-Ray single crystal diffraction analysis was carried out on 1 [Fe(NCS)2bpa2] while for 2 [Co(NCS)2bpa2] and 3 [Ni(NCS)2bpa2] the structural characterization was performed on powdered samples. UV-VIS results were consistent with high-spin metallic cations in tetragonally distorted octahedral fields. Although in the three compounds weak antiferromagnetic coupling has been observed taking place through the –M–(bpa)2–M– bridges, for the theoretical analysis of the global magnetic behaviour of all of them some other effects have been considered, i.e. zero field splitting and spin–orbit coupling.