Phase transitions in (C7H12N2)2[SnCl6]Cl2·1.5H2O crystal, studied by NMR and infrared spectroscopy
| Autor: | Faouzi Hlel, Rachid Hajji |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Phase transition
010304 chemical physics Chemistry Chemical shift Relaxation (NMR) Infrared spectroscopy General Chemistry Nuclear magnetic resonance spectroscopy Carbon-13 NMR 010402 general chemistry 01 natural sciences 0104 chemical sciences Crystallography Differential scanning calorimetry 0103 physical sciences General Materials Science Perovskite (structure) |
| Zdroj: | Magnetic Resonance in Chemistry. 57:479-488 |
| ISSN: | 0749-1581 |
| DOI: | 10.1002/mrc.4878 |
| Popis: | The (C7 H12 N2 )2 [SnCl6 ]Cl2 ·1.5H2 O complex is a new member of the family of hybrid organic-inorganic perovskite compounds. It exhibits two order-disorder phase transitions with changes in the conformation of aromatic cations at the two transition temperatures 360 and 412 K. Differential scanning calorimetry, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FT-IR) spectroscopy were used to investigate these phase transitions. These transition mechanisms were investigated in terms of the spin-lattice relaxation times T1 for 1 H static NMR and the chemical shifts for 13 C CP-MAS. The temperature dependence of T1(1 H) and 13 C chemical shifts are changed near TC1 and TC2 . Furthermore, the splitting for 13 C NMR signals in Phases (II) and (III) indicated a ferroelastic characteristic of the compound. In addition, FT-IR results indicate that the ordered conformational structure of aromatic cations undergoes a remarkable disorder with increasing temperature. The NMR and FT-IR studies suggest that the phase transition mechanisms are related to the reorientational motion of [C7 H12 N2 ]2+ cations as a whole. Phase transition was examined in light of the interesting optical properties of this material. |
| Databáze: | OpenAIRE |
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