Spin transition in a triazine-based Fe(II) complex: variable-temperature structural, thermal, magnetic and spectroscopic studies

The crystal structure of a new monomeric Fe(II) spin-crossover thiocyanate complex with a polypyridyl triazine-based ligand is reported at three temperatures. Spectroscopic, thermal and magnetic studies are presented that allowed the characterization of the thermal spin-crossover experienced by this compound and its cooperative character. The temperature of the transition is close to 200 K and the process is characterized by thermodynamic variations of Delta H-trs = 7.22( 2) kJ mol(-1) and Delta S-trs = 36.4( 2) J mol(-1) K-1.