Metal-to-Metal Electron Transfer in Co/Fe Prussian Blue Molecular Analogues: The Ultimate Miniaturization

Co/Fe Prussian Blue analogues are
known to display both thermally
and light induced electron transfer attributed to the switching between
diamagnetic {FeIILS(μ‑CN)­CoIIILS} and paramagnetic {FeIIILS(μ‑CN)­CoIIHS} pairs (LS
= low spin; HS = high spin). In this work, a dinuclear cyanido-bridged
Co/Fe complex, the smallest {Fe­(μ‑CN)­Co} moiety
at the origin of the remarkable physical properties of these systems,
has been designed by a rational building-block approach. Combined
structural, spectroscopic, magnetic and photomagnetic studies reveal
that a metal-to-metal electron transfer that can be triggered in solid
state by light, temperature and solvent contents, is observed for
the first time in a dinuclear complex.