Reversible switching of a cobalt complex by thermal, pressure, and electrochemical stimuli: Abrupt, complete, hysteretic spin crossover

Abstract

Triply switchable [Co II(dpzca) 2] shows an abrupt, reversible, and hysteretic spin crossover (T 1/2↓ = 168 K, T 1/2↑ = 179 K, and δT 1/2 = 11 K) between the high-spin (HS) and low-spin (LS) states of cobalt(II), both of which have been structurally characterized. The spin transition is also reversibly triggered by pressure changes. Moreover, in a third reversible switching mechanism for this complex, the magnetic properties can be switched between HS cobalt(II) and LS cobalt(III) by redox. © 2011 American Chemical Society.