Comparative studies of vibrational properties and phase transitions in perovskite‐like frameworks of [(C₃H₇)₄N][M(N(CN)₂)₃] with MMn, Co, Ni

Abstract

We report for the first time phonon properties of [(C3H7)4N][M(N(CN)2)3] with MMn, Co, Ni (TPrAM), and theoretical Density Functional Theory (DFT) data for isolated TPrA+ cation obtained using harmonic and anharmonic approximation. Manganese compound undergoes one structural temperature‐induced phase transition, whereas others exhibit multiple structural phase transitions in a broad temperature ranges. Temperature‐dependent Raman studies let us obtain insight into mechanism of these transitions. The phase transition at about 330 K in TPrAMn involves mainly the ordering of the dca bridges coordinating Mn2+ ions and is accompanied by partial ordering of the TPrA+ cations and their shift in the cavities. However, the behavior of TPrANi is different. In particular, very large broadening of bands, attributed to vibrations of the dca and TPrA+ cations, revealed highly dynamic nature of these groups in all phases. This result indicates that observed phase transitions are associated with changing the dynamic disorder of both organic ions. Raman studies also show that all phase transformations are accompanied by slight modification in tilting of the NiN6 octahedra caused by shift of the TPrA+ ions in the cavities.

Recent advances in linear and nonlinear Raman spectroscopy. Part XIV

“…Cai et al [ 154 ] performed a quantitative analysis of stibnite content in raw ore by Raman spectroscopy and chemometric tools. Ciupa‐Litwa et al [ 155 ] carried out comparative studies of the vibrational properties and phase transitions in perovskite‐like frameworks with Mn, Co, and Ni. Their result indicates that observed phase transitions are associated with changing the dynamic disorder of both organic ions.…”