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Int. J. Mol. Sci. 2011, 12(8), 5339-5351; doi:10.3390/ijms12085339
Communication

Spin Transition Sensors Based on β-Amino-Acid 1,2,4-Triazole Derivative

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Received: 11 July 2011; in revised form: 11 August 2011 / Accepted: 12 August 2011 / Published: 18 August 2011
(This article belongs to the Special Issue Recent Advances in Molecular Electronics)
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Abstract: A β-aminoacid ester was successfully derivatized to yield to 4H-1,2-4-triazol-4-yl-propionate (βAlatrz) which served as a neutral bidentate ligand in the 1D coordination polymer [Fe(βAlatrz)3](CF3SO3)2·0.5H2O (1·0.5H2O). The temperature dependence of the high-spin molar fraction derived from 57Fe Mossbauer spectroscopy recorded on cooling below room temperature reveals an exceptionally abrupt single step transition between high-spin and low-spin states with a hysteresis loop of width 4 K (Tc = 232 K and Tc = 228 K) in agreement with magnetic susceptibility measurements. The material presents striking reversible thermochromism from white, at room temperature, to pink on quench cooling to liquid nitrogen, and acts as an alert towards temperature variations. The phase transition is of first order, as determined by differential scanning calorimetry, with transition temperatures matching the ones determined by SQUID and Mössbauer spectroscopy. The freshly prepared sample of 1·0.5H2O, dried in air, was subjected to annealing at 390 K, and the obtained white compound [Fe(βAlatrz)3](CF3SO3)2 (1) was found to exhibit a similar spin transition curve however much temperature was increased by (Tc = 252 K and Tc = 248 K). The removal of lattice water molecules from 1·0.5H2O is not accompanied by a change of the morphology and of the space group, and the chain character is preserved. However, an internal pressure effect stabilizing the low-spin state is evidenced.
Keywords: spin crossover; aminoacid triazoles; iron(II); coordination polymers
spin crossover; aminoacid triazoles; iron(II); coordination polymers
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Dîrtu, M.M.; Schmit, F.; Naik, A.D.; Rotaru, A.; Marchand-Brynaert, J.; Garcia, Y. Spin Transition Sensors Based on β-Amino-Acid 1,2,4-Triazole Derivative. Int. J. Mol. Sci. 2011, 12, 5339-5351.

AMA Style

Dîrtu MM, Schmit F, Naik AD, Rotaru A, Marchand-Brynaert J, Garcia Y. Spin Transition Sensors Based on β-Amino-Acid 1,2,4-Triazole Derivative. International Journal of Molecular Sciences. 2011; 12(8):5339-5351.

Chicago/Turabian Style

Dîrtu, Marinela M.; Schmit, France; Naik, Anil D.; Rotaru, Aurelian; Marchand-Brynaert, J.; Garcia, Yann. 2011. "Spin Transition Sensors Based on β-Amino-Acid 1,2,4-Triazole Derivative." Int. J. Mol. Sci. 12, no. 8: 5339-5351.



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