Deuterium isotope effect on the high-spin α low-spin transition in deuterated solvates of tris(2-picolylamine) iron(II) chloride

Abstract Temperature-dependent 57 Fe Mossbauer spectra of the spin cross-over systems [Fe(2-pic) 3 ]Cl 2 ·Sol(2-pic = 2-picolylamine, Sol = C 2 H 5 OD and CH 3 OD) with deuterated crystal solvent molecules are compared with non-deuterated analogues from previous investigations. A pronounced H/D isotope effect has been observed in the temperature dependence of the qudrupole doublet of the high-spin (HS) State of iron(Il). The transition temperature T c is shifted upwards by ≈15 K upon deuteration in both solvates.