Structure of a spin-crossover Fe(II)–1,2,4-triazole polymer complex dispersed in an isotactic polystyrene matrix

Rubio, M.; Hernández, Rebeca; Nogales, Aurora; Roig, Anna; López, Daniel

doi:10.1016/j.eurpolymj.2010.10.029

Cited by 39 publications

(32 citation statements)

References 33 publications

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“…However, the drying process has an additional effect as it shifts the transition to higher temperatures, that may be attributed to a positive pressure effect of the network densification on the nanocrystals. [57][58][59][60] This effect could also explain the higher transition temperature of the composite compared to the particle free system.…”

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confidence: 91%

Preserving the spin transition properties of iron-triazole coordination polymers within silica-based nanocomposites

et al. 2017

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Preserving the spin transition properties of iron-triazole coordination polymers within silica-based nanocomposites †T. Coradin * a and C. Roux* a One dimensional iron(II) coordination polymers formed from 1,2,4-triazole bridging ligands are a unique class of spin-crossover materials (SCO). The integration of those coordination polymers into devices for practical applications remains a major challenge. Using a nanocomposite approach based on the control of coordination polymer interactions with chemically engineered silica particles, we show that we can achieve in situ gelation, while preserving the SCO properties of the solid state. Tuning the interface between the two phases of a composite provides a unique way to synergistically adjust the material's structure and the cooperativity associated with its transition properties. The strategy described here should allow for bridging the gap between soft and crystalline functional inorganic materials.

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confidence: 91%

Preserving the spin transition properties of iron-triazole coordination polymers within silica-based nanocomposites

et al. 2017

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“…Fig. [8][9][10] Several SCO nanoparticles based on Fe(II) complexes were prepared and embedded in matrices, such as SiO 2 , 11 Ni, 12 and CsFe[Cr(CN) 6 ], to name a few. 6,7 One interesting aspect in this area concerns the case of SCO hybrid materials where a given complex can feel the constraint of a given matrix which is equivalent to the application of additional pressure.…”

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confidence: 99%

Water effect on the spin-transition behavior of Fe(ii) 1,2,4-triazole 1D chains embedded in pores of MCM-41

et al. 2015

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The spin-crossover (SCO) compounds [Fe(Htrz) 3 ](BF 4 ) 2 ÁH 2 O (SCO-1) and [Fe(Htrz) 2 trz]BF 4 (SCO-2) (Htrz = 1,2,4triazole) were embedded in the pores of mesostructured silica MCM-41 to yield SCO@MCM composites as evidenced by electron microscopy, gas sorption studies, powder X-ray diffractometry, atomic absorption and infrared spectrometry. Studies of the temperature-induced spin crossover behavior of the composites by temperature-variable 57 Fe Mössbauer spectroscopy, magnetic and differential scanning calorimetry measurements and optical reflectivity indicate that the spin transition of the composites was significantly shifted for SCO-1@MCM to higher temperature in comparison to bulk SCO-1 compounds while the shift for SCO-2 was negligible. These shifts in the transition temperature for SCO-1@MCM [versus bulk SCO-1] amounted to T m c = 371/376 K [282/291 K] and T k c = 340/345 K [276/286 K] (magnetic/optical reflectivity data) with a broadening of the hysteresis by 25-26 K relative to bulk SCO-1 (varying slightly with the used method). The significant difference in the SCO behavior of the similar materials SCO-1 and SCO-2 when embedded in the MCM-41 matrix is assigned to the hydration of the SCO-1@MCM material. Water is apparently crucial in transmitting the confinement pressure or matrix effect on the spin transition when the SCO compound is embedded between the pore walls.

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“…Another modification of the triazole ligand is the construction of the dendrimer by substituting it with the dendrons of a benzyl ether-type unit [14][15][16][17]. Another approach is embedding the complex in a polymer matrix, such as polystyrene [18], polymethyl methacrylate [19,20], or Nafion [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Control of Spin-Crossover Phenomena in One-Dimensional Triazole-Coordinated Iron(II) Complexes by Means of Functional Counter Ions

et al. 2017

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Abstract:The spin-crossover (SCO) phenomenon between a high-spin and a low-spin state has attracted much attention in the field of materials science. Among the various kinds of SCO complexes, the triazole-bridged iron(II) polymeric chain system, [Fe(II)(R-trz) 3 ]X 2 ·xH 2 O (where trz is triazole and X is the anion), exhibiting the SCO phenomenon with thermal hysteresis around room temperature, has been extensively studied from the viewpoint of molecular memory and molecular devices. In connection with this system, we have controlled the SCO phenomenon according to the characteristic properties of counter ions. In the case of X being C n H 2n+1 SO 3 − , the spin transition temperature (T 1/2 ) increases with increasing the length (n) of the alkyl chain of the counter ion and saturates above n = 5, which is attributed to the increase in the intermolecular interaction of the alkyl chains of C n H 2n+1 SO 3 − , called the fastener effect. The hysteresis width of T 1/2 decreases with increasing n, showing the even-odd, also known as parity, effect. In the cases where X is toluenesulfonate (tos: CH 3 C 6 H 4 SO 3 − ) and aminobenzenesulfonate (abs: NH 2 C 6 H 4 SO 3 − ), T 1/2 and its hysteresis width vary drastically with the structural isomerism (ortho-, metha-, and para-substitution) of counter ions, which implies the possibility of photoinduced spin transition by means of the photoisomerization of counter ions. From this strategy, we have synthesized [Fe(II)(NH 2 -trz) 3 ](SP150) 2 ·2H 2 O (SP150 = N-alkylsulfonated spiropyran) and investigated the SCO phenomenon. Moreover, we have developed [Fe(II)(R-trz) 3 ]@Nafion films exhibiting spin transition around room temperature, where the Nafion membrane behaves as a counter anion as well as a transparent substrate, and investigated the photogenerated high-spin state below 35 K. The lifetime of the photogenerated high-spin state strongly depends on the intensity of irradiated light.

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Structure of a spin-crossover Fe(II)–1,2,4-triazole polymer complex dispersed in an isotactic polystyrene matrix

Cited by 39 publications

References 33 publications

Preserving the spin transition properties of iron-triazole coordination polymers within silica-based nanocomposites

Preserving the spin transition properties of iron-triazole coordination polymers within silica-based nanocomposites

Water effect on the spin-transition behavior of Fe(ii) 1,2,4-triazole 1D chains embedded in pores of MCM-41

Control of Spin-Crossover Phenomena in One-Dimensional Triazole-Coordinated Iron(II) Complexes by Means of Functional Counter Ions

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