Desorption/adsorption of guest molecules in a nano-porous material is one of the sensitive tools to control the nature of the host framework via the strong guest-host interaction. A Co-Fe cyanide film, Na0.20Co[Fe(CN) 6]0.71zH2O, shows a spin state transition from the high-spin (HS) phase [Co2+ (S = 3/2)-Fe3+ (S = 1 /2)] to the low-spin (LS) phase [Co3+ (S = O)-Fe2+ (S = 0)] at Tc = 220 K. Here, we found that the existence (Tc = 220-263 K) and nonexistence (Tc ≤ 0 K) of the phase transition reversibly switched by the site-selective desorption of the guest waters. Such a gigantic controllability of Tc is ascribed to subtle competition between the HS phase and the LS phase together with the cooperative nature of the transition.
ASJC Scopus subject areas
- Physics and Astronomy(all)