Comparative studies of vibrational properties and phase transitions in metal-organic frameworks of [NH4][M(HCOO)3] with M=Mg, Zn, Ni, Fe, Mn

• Published in: Vibrational spectroscopy 2015-03, Vol.77, p.17-24
• Main Authors: Mączka, M., Szymborska-Małek, K., Ciupa, A., Hanuza, J.
• Format: Article
• Language: English
• Subjects: Bands; Infrared; Iron; Magnesium; Manganese; Metal-organic frameworks; MOF; Nickel; Phase transformations; Phase transitions; Raman; Zinc
• ISSN: 0924-2031; 1873-3697
• DOI: 10.1016/j.vibspec.2015.02.003

•[NH4][M(HCOO)3] M=Ni, Fe, Mn were grown.•Raman and IR studies of [NH4][M(HCOO)3] were performed.•IR data confirmed an order–disorder character of the phase transitions.•Correlations between size and/or mass of divalent cation and wavenumbers were found.•Splitting and the activation energy for reorientational motions of NH4+ is proportional to Tc. Room temperature experimental infrared (IR) and Raman spectra of [NH4][M(HCOO)3] compounds with M=Mg, Zn, Ni, Fe, Mn were analyzed in order to propose the assignment of the experimental bands to the respective internal and lattice modes. We also report temperature-dependent IR studies of [NH4][Ni(HCOO)3] and [NH4][Fe(HCOO)3] in the temperature range 5–295K, and compare them with the previously reported data for the Zn and Mg analogs. The temperature-dependent data provide deeper insight into mechanism of the phase transition and relationship between the phase transition temperature and chemical composition of the studied compounds.