Broad-range spin-crossover modulation in guest-responsive 2D Hofmann-type coordination polymers

Abstract

Rationalizing the role of chemical functionalisation on the synergy between spin crossover (SCO) and guest adsorption properties in porous FeII coordination polymers is a central topic within the switchable materials...

Modulation of the spin transition in 2D Hofmann frameworks via π⋯π stacking between the axial 2,5-dipyridyl-1,3,4-oxadiazoles

“…5–11 Among them, Fe 2+ Hofmann-type SCO frameworks are one of the most notable systems. 6,10–35 These frameworks generally contain neutral bimetallic layers consisting of Fe 2+ ions and [M(CN) 4 ] 2− anions (M = Pt 2+ , Pd 2+ , Ni 2+ ) in the equatorial plane, which allow a large number of linear N-donor ligands to coordinate axially to the Fe 2+ centers in order to produce 2D/3D Hofmann SCO materials. 10 If the linear exo -bidentate ligands are used as pillars, 3D porous Hofmann SCO frameworks can be constructed, 11 while 2D Hofmann SCO networks will be built if the axial ligands are merely monodentate.…”

“…12 Since the monodentate ligand is always more readily available than the bidentate one, the 2D Hofmann SCO networks can be more easily constructed, which will provide a good opportunity for exploring the influence of intermolecular interactions (hydrogen bonding, π⋯π stacking and interdigitated effect) on the SCO behavior. 12–35 So far, most of the monodentate axial ligands used in 2D Hofmann SCO networks are substituted pyridine derivatives, owing to their cheap and easy large-scale preparation. Moreover, pyridine derivatives modified with small substituent groups (–F, –Cl, –Br, –I, –NH 2 , etc. )…”

Guest-induced pore breathing controls the spin state in a cyanido-bridged framework

“…17,18 Noticeably, this phenomenon is hardly evidenced in rigid three-dimensional (3-D) Hofmann-type PCPs, in which strong host-guest interactions with guest molecules seem to overcome the volume change effect. [19][20][21][22] Thus, in order to successfully observe the aforementioned coupling of the crystal lattice breathing with the spin transition, one should either decrease the strength of specic host-guest interactions or increase the volume change in the breathing SCO framework. The prospective candidate can be found in the family of octacyanidometallate-based compounds {[Fe II (py) 4 ] 2 [M IV (CN) 8 ]$ xH 2 O} n (py = pyridine derivatives, M = Mo, W, Nb, Re), 23 since some of us recently demonstrated large water-induced breathing of the octacyanomolybdate(IV) coordination polymer.…”

Guest-Induced Pore Breathing Controls Spin State in a Cyanido-Bridged Framework

“…17,18 Noticeably, this phenomenon is hardly evidenced in rigid three-dimensional (3-D) Hofmann-type PCPs, in which strong host-guest interactions with guest molecules seem to overcome the volume change effect. [19][20][21][22] Thus in order to successfully observe the aforementioned coupling of the crystal lattice breathing with the spin transition, one should either decrease the strength of specific host-guest interactions or increase the volume change in the breathing SCO framework. The prospective candidate can be found in the family of octacyanidometallate-based compounds {[Fe II (py)4]2[M IV (CN)8]•xH2O}n (py = pyridine derivatives, M = Mo, W, Nb, Re) 23 , since some of us recently demonstrated large water-induced breathing of the octacyanomolybdate(IV) coordination polymer.…”