Charge Transfer‐Induced Spin‐Transitions in Cyanometallate Materials

Manipulating Slow Magnetic Relaxation by Light in a Charge Transfer {Fe2Co} Complex

“…The cyanide‐bridged iron–cobalt system, which is among the most promising switchable materials, has gained much attention owing to its high sensitivity to external thermal, electrical, optical, and mechanical stimuli . The bimetallic pairs adopt different electronic spin states from the low‐temperature (LT) diamagnetic {Fe II LS (μ‐CN)Co III LS } state to the high‐temperature (HT) paramagnetic {Fe III LS (μ‐CN)Co II HS } state, known as the charge transfer‐induced spin transition (CTIST), which is generally able to induce significantly different magnetic properties . So far, high‐dimensional and discrete cyanide‐bridged iron–cobalt materials have been reported .…”

Metal‐to‐Metal Electron Transfer: A Powerful Tool for the Design of Switchable Coordination Compounds

“…In parallel, other switching phenomena at the molecular level have been studied, but in a less extensive manner than the SCO compounds. Among them, dioxolene compounds and cyanometallates, form two other classes of well‐studied compounds, in which the switching mechanism is based on an electron transfer (ET) between the metal ion and one ligand or between two metal ions, respectively.…”

Spin-state switches in molecular materials chemistry

“…LS HS Such transitions between iron and cobalt centres are well known in large molecular clusters, polymers and in Prussianblue analogue inorganic lattices, 21 but have also recently been achieved in small complex molecules. 22 Alternatively, spin transitions can also be induced by metal-to-ligand charge transfer, which is well-known in cobalt/dioxolene chemistry for example (eq 2; cat = catecholate, sq  = semiquinonate):…”

“…21,24 A third type of spin-state switch does not involve a spinstate change at individual metal ions, but instead reflects large changes to magnetic coupling interactions between radical spins in a molecule or material. Again, two main classes can be identified under this heading.…”

“…First, are heterometallic metal/cyanide assemblies. 21 The most common examples contain iron and cobalt centres, which can undergo a thermally induced valence tautomerism (eq 1; HS = high-spin, LS = low-spin):…”