Reversible guest-induced gate-opening with multiplex spin crossover responses in two-dimensional Hofmann clathrates

Abstract

Spin crossover (SCO) compounds are a very attractive type of switchable materials due to their potential application in molecular devices. Rational chemical tailoring of these switchable compounds is key for...

A spin-crossover framework endowed with pore-adjustable behavior by slow structural dynamics

“…9 K ( T c1 ↓ = 196 K, T c1 ↑ = 205 K) and 15 K ( T c2 ↓ = 166 K, T c2 ↑ = 181 K). Such a hysteretic spin transition is usually caused by strong cooperative interactions among the magnetic centers 41 , 42 . The shifts in the Fe−N bond lengths confirm the spin transition of Fe II ions in 1 ·9/2H 2 O.…”

“…A CO 2 -induced paramagnetic–to–ferrimagnetic variation was recently demonstrated in a porous compound, [{Ru 2 (F 3 PhCO 2 ) 4 } 2 TCNQ(OEt) 2 ]·3DCM (TCNQ(OEt) 2 = 2,5-diethoxy-7,7,8,8-tetracyanoquinodimethane; F 3 PhCO 2− = 2,4,6-trifluorobenzoate; DCM = dichloromethane), as a result of electron transfer and a structural transition involved in the adsorption of CO 2 molecules 37 . In addition to radical molecules, the spin-crossover (SCO) compounds of 3 d 4 −3 d 7 metal ions, whose spin states can be interconverted between high-spin (HS) and low-spin (LS) states in response to external stimuli, are also susceptible to the structural changes in the coordination geometry of metal centers 38 – 41 . Therefore, the intercorrelation between the guests and SCO frameworks potentially leads to intriguing magnetic switching that directly entangles the structural transformations involved in guest adsorption.…”

Bistable Hofmann-Type FeII Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces

“…Two-dimensional (2D) Hofmann-type Fe II coordination polymers with general formula {Fe II (L ax ) 2 [M II (CN) 4 ]} represent an important source of SCO compounds, where M II = Pt II , Pd II , or Ni II and L ax is a terminal monotopic axial ligand based on pyridine/pyridine-like , and triazole rings . The Fe II ions are equatorially connected through square-planar [M II (CN) 4 ] 2– anionic metalloligands affording robust infinite [Fe II [M II (CN) 4 ] ∞ layers that are the origin of the cooperativity typically exhibited by these compounds.…”

Old Materials for New Functions: Recent Progress on Metal Cyanide Based Porous Materials

“…In 2019, Real et al reported the construction of isoreticular 2D Hofmann-type MOF Fe(5-NH 2 pym) 2 [M(CN) 4 ] (M = Pt or Pd) with 5-aminopyrimidine (5-NH 2 pym) as ligands, in which the amine groups and aromatic nitrogen atoms served as hydrogen bonding donors and acceptors, enabling enough pore space for the accommodation of guest molecules. [40] The as-synthesized phase with water as guest molecules can be dehydrated and reversibly adsorb/desorb protic solvent molecules, such as water, methanol, and ethanol, as evidenced by single-crystal diffraction studies. The vapor sorption isotherms of the bulk material showed gate-opening effect for both compounds upon these solvent vapors, demonstrating the structural transformation that is not observed in the bulk prototypical Fe(py) 2 [M(CN) 4 ] and its derivatives.…”