Reverse Spin Transition Triggered by a Structural Phase Transition

Abstract

Designing molecules that could be used for information processing and information storage is one of the main challenges in molecular materials science. Molecules that are suitable for such applications must be bistable: a characteristic that allows the presence of two different stable electronic states over a certain range of external perturbation. Typical examples of molecular species that exhibit such bistability are the spin-crossover (SCO) compounds. Since the discovery of the first SCO compound,[1] a variety of d n (n = 4-7) transition metal compounds exhibiting bistability between the high-spin (HS) and low-spin (LS) states have been reported. [2][3][4] Spin transition can be induced by variation of temperature, pressure, or illumination.[2-9] In general, temperature-dependent SCO behavior involves reversible spin transition from LS to HS upon heating and from HS to LS upon cooling.Although the SCO transition is due to the electronic structure of the single molecule and can be observed even in

Spin-crossover and LIESST Effect for Iron(III) Complex Based on π–π Stacking by Coordination Programming

“…The » m T value for 1 is 0.53 cm 3 K mol ¹1 at 5 K, which is in the range expected for an LS iron(III) ion. On heating, two-step SCO behavior was observed.…”

Investigation of the Spin Crossover Properties of Three Dinulear Fe(II) Triple Helicates by Variation of the Steric Nature of the Ligand Type

“…The intricate effect of intermolecular interactions and magnetic coupling on the cooperativity of SCO systems has greatly complicated this understanding. Spin transition is generally observed in first-row transition metal coordination complexes with electronic configurations in the range d 4 -d 7 [9,10]. These transitions produce a change in the magnetic, optical and structural properties of the material.…”

Inorganic–Organic Hybrid Surfactant Crystals: Structural Aspects and Functions

“…These hybrid surfactant crystals containing coordinated metal M n+ cations exhibit spin crossover [56,[58][59][60] and valence tautomerism [38] induced by changes in the coordination environment. Thermal motion in the long amphiphilic chains plausibly affects the electronic spin state of metal cations.…”

“…Although it is difficult to strictly categorize these coordination and packing modes due to the variety of the ligand structures, monodentate ligands coordinate in both a symmetric and asymmetric manner (Figure 4a accurate coordination geometry. There are six typical coordination and packing modes: asymmetric coordination of one single-chained ligand (Figure 4a) [38,39,55,61,65], symmetric coordination of two single-chained ligands lying on the opposite sides of the metal cation (Figure 4b) [41][42][43]49,51,53,55,59,60], symmetric coordination of one double-chained ligand with two chains at the opposite sides of the metal cation (Figure 4c) [45,47,54,55,62], asymmetric coordination of two singlechained ligands lying on the same side of the metal cation (Figure 4d) [44,46,48,56], asymmetric coordination of one double-chained ligand with narrow space between the chains (Figure 4e) [50,54,63], and asymmetric coordination of one double-chained ligand with wide space between the chains (Figure 4f) [41]. However, the essential feature is the formation of a layered structure that consists of M n+ inorganic layers and surfactant organic layers.…”

“…Crystals 2016, 6, 24 3 of 20 [58][59][60], 1,4,7-triazacyclononane [61]), and tetradentate ligands (Schiff base [62][63][64], 1,3,5,8,12-pentaazacyclotetradecane [65]). Nitrogen atom-containing ligands have often been used, presumably due to the stability and versatility of coordination bonds.…”