Preparation, Thermal, and Physical Properties of Perovskite-Type (C3H7NH3)2CdCl4 Crystals

Ae Lim,Sun Kim

doi:10.3390/cryst9020108

Abstract

To investigate the thermal and physical properties of perovskite-type (C3H7NH3)2CdCl4, its temperature-dependent chemical shifts and spin–lattice relaxation times are measured using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), magic angle spinning nuclear magnetic resonance (MAS NMR), and static NMR methods. Above 300 K, two phase transitions are observed at 398 K and 538 K. Each proton and carbon in the (C3H7NH3) cation is distinguished in the MAS NMR results. The environments around 1H, 13C, and 14N do not change with temperature according to the NMR spectra. In contrast, the resonance frequency of 113Cd in the CdCl6 octahedra decreases with increasing temperature, indicating an environmental change. The uniaxial rotations for 1H and 13C have high mobility at both high and low temperatures, and these are related to the phase transitions. In addition, the molecular motion of 113Cd in the anion becomes activated upon raising the temperature.

Highlights

Organic–metal hybrid compounds provide many opportunities for potential applications [1,2,3,4,5,6].In these materials, a large number of organic and metal moieties with different properties can be combined within a single structure
N–H···X hydrogen bonds are formed between the NH3 + polar heads of the alkylammonium and the halogen atoms, and the polar heads occupy cavities among the octahedra [17]
The structural phase transition at low temperature was reported to be connected with a change in the motion of the alkyl groups

Summary

Introduction

Organic–metal hybrid compounds provide many opportunities for potential applications [1,2,3,4,5,6] In these materials, a large number of organic and metal moieties with different properties can be combined within a single structure. N–H···X hydrogen bonds are formed between the NH3 + polar heads of the alkylammonium and the halogen atoms, and the polar heads occupy cavities among the octahedra [17] In these materials, the cation dynamics and ion–ion interactions through hydrogen bonds affect the physical properties and thermal properties of structural phase transitions. The structural phase transition at low temperature was reported to be connected with a change in the motion of the alkyl groups. The ferroelastic domain walls were observed by optical polarizing microscopy

Experimental Section

H7 andwith

C T1ρ values near when

Chemical shift

Conclusions

H MAS were observed at