A density functional study of the spin state energetics of polypyrazolylborato complexes of first-row transition metals

Abstract

Density Functional Theory (DFT) was used to analyse and explain spin state energetics of first-row transition metals (Mn-II, Fe-II, Co-II; Cr-III, Mn-III, Fe-III, Co-III; Mn-IV) in polypyrazolylborato complexes. We explored the effects of substitutions at the 3 and 5 positions of the pyrazolyl rings, as well as the influence of Jahn-Teller (JT) distortions on spin-state switching. Although the stabilizations due to JT distortion are sometimes substantial, this does not lead to switching of the spin ground-state. On the other hand, electron withdrawing or donating substituents do lead to significant changes in the spin-crossover (SCO) properties of the investigated complexes.