Pressure-Induced Cooperative Spin Transition in Iron(II) 2D Coordination Polymers: Room-Temperature Visible Spectroscopic Study

Levchenko, G. G.; Bukin, G. V.; Terekhov, S. A.; Gaspar, Ana B.; Martínez, Vladimir; Muñoz, M. Carmen; Real, José Antonio

doi:10.1021/jp201585x

Cited by 27 publications

(38 citation statements)

References 43 publications

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“…Regarding this issue, very few attempts have been noticed to record the (p-T) phase diagram by using various detection techniques such as optical reflectivity [19][20][21][29][30][31], magnetic techniques [15][16][17][18][32][33][34], X-ray and neutron diffraction [35][36][37][38][39]. This lack of data could be explained by the difficulty to obtain small variations in the applied pressure in both loading and unloading processes, at variable temperatures.…”

Section: Resultsmentioning

confidence: 99%

Thermo- and piezochromic properties of [Fe(hyptrz)]A2·H2O spin crossover 1D coordination polymer: Towards spin crossover based temperature and pressure sensors

Jureschi

Rusu

Codjovi

et al. 2014

Physica B: Condensed Matter

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Section: Resultsmentioning

confidence: 99%

Thermo- and piezochromic properties of [Fe(hyptrz)]A2·H2O spin crossover 1D coordination polymer: Towards spin crossover based temperature and pressure sensors

Jureschi

Rusu

Codjovi

et al. 2014

Physica B: Condensed Matter

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“…In particular, quantitative optical absorption measurements on crystals can be carried out using a cheap optical microscope and an appropriate bandpass filter. Optical spectroscopy has been used since the onset of SCO research [10,11,16,49,59,132] eight orders of magnitude acceleration of the low-temperature tunnelling process could be evidenced for an external pressure of 2 GPa. We expect that recent ultrafast (fs) optical spectroscopy experiments on SCO samples will be also complemented by measurements under pressure in the near future.…”

Section: Other Detection Methodsmentioning

confidence: 99%

“…Figure 10 shows cyanide-based SCO polymers. Recently, a theoretical study has demonstrated that the changes of the elastic and inelastic forces in the crystal as a function of pressure or temperature determine the behaviour of the spin transition in these polymers [132,148].…”

Section: Compounds With Abrupt Thermal Spin Transition Accompanied Wimentioning

confidence: 99%

Pressure effect investigations on spin-crossover coordination compounds

Gaspar

Molnár

Rotaru

et al. 2018

Comptes Rendus. Chimie

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The piezo-chromic properties of spin crossover complexes have been recognized for a long time, with increasing pressure favouring the low spin state due to its smaller volume and therefore shifting the spin equilibrium towards higher temperatures and accelerating the relaxation at a given temperature. However, the interpretation and quantification of pressure induced changes have been several times compromised by the relatively poor and incomplete spectral and structural information provided by the detection methods or due to the experimental difficulties related to the need for hydrostatic conditions at low temperatures. The present review is therefore primarily focused on these experimental aspects of high pressure spin crossover research providing an overview of methods of pressure generation and associated detection methods as well as on selected recent results.Résumé: Les propriétés piézo-chromiques de complexes à transition de spin ont été identifiées depuis longtemps. Du point de vue théorique, l'application d'une pression favorise l'état bas spin, de plus petit volume. Ainsi les températures de transition augmentent et les cinétiques de relaxation s'accélèrent sous pression. Toutefois, l'interprétation et la quantification des modifications induites par la pression restent un challenge en raison de la difficulté d'obtenir des données structurales et spectrales fiables dans des conditions de pression hydrostatique. Ceci est d'autant plus vrai lorsque les hautes pressions et les basses températures doivent être combinées. Ainsi, l'objectif principal du présent article est une mise au point sur les techniques utilisées pour l'étude des composés à transition de spin sous pressionillustrées par une sélection de résultats récents.the piston(s) in the desired position even after removing the cell from the press. These (relatively) small, autonomous cells are particularly popular because they can be easily combined with cryostats, magnetometers and other equipment [26,82,109]. While several designs, both home built and commercially available have been used in the study of SCO materials, the principle upon which they work is similar. In general the sample is placed in a Teflon capsule J Rotaru et al. have been analysed the thermal behaviour of the spin transition complexes [FexZn1-x(btr)2(NCS)2]H2O (for x=0.6 and x=1) by diffuse reflectivity measurements, under constant pressure in the range 1-1600 bars obtained with a gas pressure cell [186]. I J , as shown in Figure 24.

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“…Fig. 41,42 The spin transitions of the SCO@MCM composites were studied optically under a nitrogen atmosphere to exclude any potential oxidation of the samples in air. 7 Hence, the change in spin state can also be followed by optical reflectance measurements in the solid state.…”

Section: Optical Reflectivity Measurementsmentioning

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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Pressure-Induced Cooperative Spin Transition in Iron(II) 2D Coordination Polymers: Room-Temperature Visible Spectroscopic Study

Cited by 27 publications

References 43 publications

Thermo- and piezochromic properties of [Fe(hyptrz)]A2·H2O spin crossover 1D coordination polymer: Towards spin crossover based temperature and pressure sensors

Thermo- and piezochromic properties of [Fe(hyptrz)]A2·H2O spin crossover 1D coordination polymer: Towards spin crossover based temperature and pressure sensors

Pressure effect investigations on spin-crossover coordination compounds

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

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