Unprecedented Multi‐Stable Spin Crossover Molecular Material with Two Thermal Memory Channels

Abstract

Two in one: A new iron(II) complex with short alkyl substituents exhibits an unprecedented bimodal behavior governed by the coexistence of three phases: two structurally different low-spin phases and one high-spin phase. The compound features two distinct well-separated strong cooperative spin-crossover transitions by varying the scan rate (see graphic).

Sliding Polymeric Layers and Anion Displacement Coupled with Spin Crossover in Two‐Dimensional Networks of [Fe(hbtz)2(CH3CN)2](BF4)2

“…In the close vicinity of metal ions, one can also observe structural alterations occurring without change of the coordination number and depending, for example, on rotation of coordinated 1,2,4‐triazole, tetrazole, or pyrazine rings as well as associated with reorientation of the coordinated thiocyanate anions or neutral nitrile molecules . Structural alterations may also proceed in more distant regions of the ligand molecule including its substituents . In the coordination polymers, perturbation spreading along bridging directions may cause an elongation/shrinkage of bridging ligands, which results from ligand elasticity or conformational freedom of the alkyl spacers .…”

“…[16] Structurala lterations may also proceed in more distant regions of the ligand molecule includingi ts substituents. [17] In the coordination polymers, perturbation spreading along bridging directions may cause an elongation/shrinkage of bridgingl igands, which results from ligand elasticityo rc onformational freedom of the alkyl spacers. [18] Non-coordinated anions, such as perchlorate, tetrafluoroborate, and hexafluorophosphate represent another group exhibitingthe ability to undergo structuralchanges, particularly depending on their reorientation.…”

Hysteresis and change of transition temperature in thin films of Fe{[Me2Pyrz]3BH}2, a new sublimable spin-crossover molecule

“…13 The thermal transition exhibits a hysteresis and a particular asymmetric shape: T HS→ LS = 174 K and T LS→ HS = 199 K. The origin of the asymmetric shape is ascribed to a crystal phase transition. 24,25 We attempted temperature dependent X-ray diffraction (XRD) on Fe-pyrz monocrystals but the crystals shattered when the temperature was lowered below the spin transition temperature, which supports a crystal phase transition, as phase changes might exert physical strain on the crystal.…”

Enhanced Activity and Acid pH Stability of Prussian Blue-type Oxygen Evolution Electrocatalysts Processed by Chemical Etching

“…[15][16][17][18][19][20][21][22][23][24][25][26][27] Most reported complexes with hysteretic SCO are mononuclear or polymeric Fe II com-pounds, typically with neutral or cationic overall charge. Our group has focused in the search for anionic SCO complexes to increase their processing capabilities when incorporated into hybrid materials.…”