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Fe-II spin transition materials including an amino-ester 1,2,4-triazole derivative, operating at, below, and above room temperature

(2016) INORGANIC CHEMISTRY. 55(9). p.4278-4295
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Abstract
A new family of one-dimensional Fe-II 1,2,4-triazole spin transition coordination polymers for which a modification of anion and crystallization solvent can tune the switching temperature over a wide range, including the room temperature region, is reported. This series of materials was prepared as powders after reaction of ethyl-4H-1,2,4-triazol-4-yl-acetate (aEtGlytrz) with an iron salt from a MeOH/H2O medium affording: [Fe(aEtGlytrz)(3)](ClO4)(2) (1); [Fe(aEtGlytrz)(3)](ClO4)(2)center dot CH3OH (2); [Fe(aEtGlytrz)(3)](NO3)(2)center dot H2O (3); [Fe(aEtGlytrz)(3)](NO3)(2) (4); [Fe(aEtGlytrz)(3)](BF4)(2)center dot 0.5H(2)O (5); [Fe(aEtGlytrz)(3)](BF4)(2) (6); and [Fe(aEtGlytrz)(3)](CF3SO3)2 center dot 2H(2)O (7). Their spin transition properties were investigated by Fe-57 Mossbauer spectroscopy, superconducting quantum interference device (SQUID) magnetometry, and differential scanning calorimetry (DSC). The temperature dependence of the high-spin molar fraction derived from Fe-57 Mossbauer spectroscopy in 1 reveals an abrupt single step transition between low-spin and high-spin states with a hysteresis loop of width 5 K (Tc up arrow = 296 K and Tc down arrow = 291 K). The properties drastically change with modification of anion and/or lattice solvent. The transition temperatures, deduced by SQUID magnetometry, shift to Tc up arrow = 273 K and Tc down arrow = 263 K for (2), Tc up arrow = 353 K and Tc down arrow = 333 K for (3), Tc up arrow = 338 K and Tc down arrow = 278 K for (4), T up arrow = 320 K and T down arrow = 305 K for (5), Tc up arrow = 106 K and Tc down arrow = 92 K for (6), and T up arrow = 325 K and T down arrow = 322 K for (7). Annealing experiments of 3 lead to a change of the morphology, texture, and magnetic properties of the sample. A dehydration/rehydration process associated with a spin state change was analyzed by a mean-field macroscopic master equation using a two-level Hamiltonian Ising-like model for 3. A new structural-property relationship was also identified for this series of materials [Fe(aEtGlytrz)(3)](anion)(2)center dot nSolvent based on Mossbauer and DSC measurements. The entropy gap associated with the spin transition and the volume of the inserted counteranion shows a linear trend, with decrease in entropy with increasing the size of the counteranion. The first materials of this substance class to display a complete spin transition in both spin states are also presented.
Keywords
WIDE THERMAL HYSTERESIS, CROSSOVER COORDINATION POLYMERS, MOLECULAR MATERIALS, IRON(II) COMPLEXES, PHASE-TRANSITION, ELECTRONIC DEVICES, CRYSTAL-STRUCTURES, OPTICAL-DETECTION, FE(II) COMPLEXES, CHAIN COMPOUND

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Chicago
Dîrtu, Marinela M, Anil D Naik, Aurelian Rotaru, Leonard Spinu, Dirk Poelman, and Yann Garcia. 2016. “Fe-II Spin Transition Materials Including an Amino-ester 1,2,4-triazole Derivative, Operating at, Below, and Above Room Temperature.” Inorganic Chemistry 55 (9): 4278–4295.
APA
Dîrtu, M. M., Naik, A. D., Rotaru, A., Spinu, L., Poelman, D., & Garcia, Y. (2016). Fe-II spin transition materials including an amino-ester 1,2,4-triazole derivative, operating at, below, and above room temperature. INORGANIC CHEMISTRY, 55(9), 4278–4295.
Vancouver
1.
Dîrtu MM, Naik AD, Rotaru A, Spinu L, Poelman D, Garcia Y. Fe-II spin transition materials including an amino-ester 1,2,4-triazole derivative, operating at, below, and above room temperature. INORGANIC CHEMISTRY. 2016;55(9):4278–95.
MLA
Dîrtu, Marinela M, Anil D Naik, Aurelian Rotaru, et al. “Fe-II Spin Transition Materials Including an Amino-ester 1,2,4-triazole Derivative, Operating at, Below, and Above Room Temperature.” INORGANIC CHEMISTRY 55.9 (2016): 4278–4295. Print.
@article{7284424,
  abstract     = {A new family of one-dimensional Fe-II 1,2,4-triazole spin transition coordination polymers for which a modification of anion and crystallization solvent can tune the switching temperature over a wide range, including the room temperature region, is reported. This series of materials was prepared as powders after reaction of ethyl-4H-1,2,4-triazol-4-yl-acetate (aEtGlytrz) with an iron salt from a MeOH/H2O medium affording: [Fe(aEtGlytrz)(3)](ClO4)(2) (1); [Fe(aEtGlytrz)(3)](ClO4)(2)center dot CH3OH (2); [Fe(aEtGlytrz)(3)](NO3)(2)center dot H2O (3); [Fe(aEtGlytrz)(3)](NO3)(2) (4); [Fe(aEtGlytrz)(3)](BF4)(2)center dot 0.5H(2)O (5); [Fe(aEtGlytrz)(3)](BF4)(2) (6); and [Fe(aEtGlytrz)(3)](CF3SO3)2 center dot 2H(2)O (7). Their spin transition properties were investigated by Fe-57 Mossbauer spectroscopy, superconducting quantum interference device (SQUID) magnetometry, and differential scanning calorimetry (DSC). The temperature dependence of the high-spin molar fraction derived from Fe-57 Mossbauer spectroscopy in 1 reveals an abrupt single step transition between low-spin and high-spin states with a hysteresis loop of width 5 K (Tc up arrow = 296 K and Tc down arrow = 291 K). The properties drastically change with modification of anion and/or lattice solvent. The transition temperatures, deduced by SQUID magnetometry, shift to Tc up arrow = 273 K and Tc down arrow = 263 K for (2), Tc up arrow = 353 K and Tc down arrow = 333 K for (3), Tc up arrow = 338 K and Tc down arrow = 278 K for (4), T up arrow = 320 K and T down arrow = 305 K for (5), Tc up arrow = 106 K and Tc down arrow = 92 K for (6), and T up arrow = 325 K and T down arrow = 322 K for (7). Annealing experiments of 3 lead to a change of the morphology, texture, and magnetic properties of the sample. A dehydration/rehydration process associated with a spin state change was analyzed by a mean-field macroscopic master equation using a two-level Hamiltonian Ising-like model for 3. A new structural-property relationship was also identified for this series of materials [Fe(aEtGlytrz)(3)](anion)(2)center dot nSolvent based on Mossbauer and DSC measurements. The entropy gap associated with the spin transition and the volume of the inserted counteranion shows a linear trend, with decrease in entropy with increasing the size of the counteranion. The first materials of this substance class to display a complete spin transition in both spin states are also presented.},
  author       = {D{\^i}rtu, Marinela M and Naik, Anil D and Rotaru, Aurelian and Spinu, Leonard and Poelman, Dirk and Garcia, Yann},
  issn         = {0020-1669},
  journal      = {INORGANIC CHEMISTRY},
  keyword      = {WIDE THERMAL HYSTERESIS,CROSSOVER COORDINATION POLYMERS,MOLECULAR MATERIALS,IRON(II) COMPLEXES,PHASE-TRANSITION,ELECTRONIC DEVICES,CRYSTAL-STRUCTURES,OPTICAL-DETECTION,FE(II) COMPLEXES,CHAIN COMPOUND},
  language     = {eng},
  number       = {9},
  pages        = {4278--4295},
  title        = {Fe-II spin transition materials including an amino-ester 1,2,4-triazole derivative, operating at, below, and above room temperature},
  url          = {http://dx.doi.org/10.1021/acs.inorgchem.6b00015},
  volume       = {55},
  year         = {2016},
}

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