Spin crossover in hydrogen-bonded frameworks of Fe^II complexes with organodisulfonate anions

Abstract

Four spin crossover FeII complexes of hydrogen-bonded frameworks were constructed from the charge-assisted hydrogen bonds between the FeII complexes and organodisulfonate anions.

Cooperativity and Metal–Linker Dynamics in Spin Crossover Framework Fe(1,2,3-triazolate)2

“…A few studies, if any have quantified the value of Γ in SCO frameworks even though they exhibit the largest cooperativity. Most reports on Γ have focused on molecular crystals with weak intermolecular interactions, giving Γ values between 1 and 5 kJ mol –1 . A a Γ value of 20 kJ mol –1 corresponds to a thermal energy of 2400 K, which is consistent with early predictions that abrupt SCO transitions arise when Γ > k B T c .…”

“…Most reports on Γ have focused on molecular crystals with weak intermolecular interactions, giving Γ values between 1 and 5 kJ mol −1 . 51 A a Γ value of 20 kJ mol −1 corresponds to a thermal energy of 2400 K, which is consistent with early predictions 21 that abrupt SCO transitions arise when Γ > k B T c . Given the T heating and T cooling of 582 K and 465, respectively, Γ would correspond to a k B T c of roughly 4−5.…”

Co-crystallisation as a modular approach to the discovery of spin-crossover materials

“…This is clearly illustrated by the fact that different polymorphs of the same molecular SCO material are known to have signicantly different transition temperatures or degrees of cooperativity. 11 Previously explored strategies for tuning the SCO behaviour of materials without changing the coordination environment around the metal centre include the incorporation of different solvent molecules into the crystal structure, [12][13][14] changing noncoordinating anions [15][16][17][18][19] and modifying remote ligand substituents. 9,20 However, each of these approaches has limitations.…”

Abundant Solvatomorphism-Tuned Spin Crossover in a Dinuclear Fe(II) Compound: Computational Insights on Molecular Distortion and Packing Effects

“…1·CH 3 OH slowly lost solvent molecules above RT (confirmed by TGA and magnetic measurements); hence, structural data above RT were not obtained because of bad crystal quality. Some structural parameters of SCO centers underwent relatively large changes during the spin transition . Therefore, we summarize the structural characteristics of [FeN 4 O 2 ] core for all crystal structures (Table ), including seven parameters which have the usual meanings reported in the literature .…”