Wydział Chemii

Magdalena Rok

Bartosz Zarychta

Rafał Janicki

Maciej Witwicki

Alina Bieńko

Grażyna Bator

2022

Inorganic Chemistry

61

5626-5636

10.1021/acs.inorgchem.2c00363

Naukowa

Angielski

Artykuł

A new organic–inorganic hybrid, AZEMnBr, has been synthesized and characterized. The thermal differential scanning calorimetry, differential thermal analysis, and thermogravimetric analyses indicate one structural phase transition (PT) at 346 and 349 K, on cooling and heating, respectively. AZEMnBr crystallizes at 365 K in the orthorhombic, Pnma, structure, which transforms to monoclinic P2₁/n at 200 K. Due to the X-ray diffraction studies, the anionic MnBr₄^2– moiety is discrete. The azetidinium cations show dynamical disorder in the high-temperature phase. In the proposed structural PT, the mechanism is classified as an order–disorder type. The structural changes affect the dielectric response. In this paper, the multiple switches between low- and high- dielectric states are presented. In addition, it was also observed that the crystal possesses a mutation of fluorescent properties between phase ON and OFF in the PT’s point vicinity. We also demonstrate that EPR spectroscopy effectively detects PTs in structurally diverse Mn(II) complexes. AZEMnBr compounds show DC magnetic data consistent with the S = 5/2 spin system with small zero-field splitting, which was confirmed by EPR measurements and slow magnetic relaxation under the moderate DC magnetic field typical for a single-ion magnet behavior. Given the above, this organic–inorganic hybrid can be considered a rare example of multifunctional materials that exhibit dielectric, optical, and magnetic activity.

Crystals, Phase transitions, Crystal structure, Insulators, Cations

CC-BY

http://dx.doi.org/10.1021/acs.inorgchem.2c00363

https://www.acs.org/content/acs/en.html