'Normal' and 'reverse' spin crossover induced by two different structural events in iron( ) coordination polymer

Conformational changes of the bridging ligand and reorientation of the anions are associated with a sequence of HT(HS) ⇆ HT(HS/LS) ⇆ IP(HS) ⇆ LT(LS) transitions accompanied by existence of two hysteresis loops, “normal” and “reverse”, separated by a region of the stability of the HS form.
In [Fe(ebbtr) (CH CN) ](CF SO ) ·4CH CN spin crossover is associated with the occurrence of “normal” and “reverse” hysteresis loops separated by a region of stable HS form. This results from – → – conformational changes of ebbtr molecules and anion reorientation, which occur in different ways during cooling and during heating.