Quantum-chemical study of the spin transition complex [Fe(bt)2(NCS)2] (bt=2,2′-bithiazoline)

The spin crossover compound [Fe(bt)2(NCS)2] has been studied by several density functionals and basis sets. In the calculation, optimized geometries of the compound in the low‐, intermediate‐, and high‐spin states, the vibrational modes and IR spectra, spin splittings energies, excited states, and UV/vis absorption spectra were obtained. © 2012 Wiley Periodicals, Inc. Spin‐crossover complexes exhibit a rich spectrum of possibilities for the development of some novel properties such as photomagnetic behavior, superconductivity, spintronic properties, etc. This paper characterizes the complex [Fe(bt)2(NCS)2] (bt=2,2′‐bithiazoline) theoretically in terms of its structure, HS–LS energy splittings, vibrational spectra, and UV/vis absorption spectroscopy. The results are expected to aid device designers in selecting this material for appropriate applications.