Phase Transition of (CH3)2CHNH3CuCl3: Crystal Growth, Crystal Structure, Coordination Geometry, and Molecular Motion

Abstract

The single crystals of (CH3)2CHNH3CuCl3 were grown, and their phase transition temperature was determined to be 341 K (TC) through differential scanning calorimetry and powder X-ray diffraction. Additionally, the structures of the single crystals were examined via single-crystal X-ray diffraction at 300 K (phase II, below TC) and 350 K (phase I, above TC) The sample underwent a thermochromic transition near the TC, changing from a low-temperature brown material to a high-temperature orange material. The phase II and I systems were triclinic "(P" "1" @#x0305;) and orthorhombic (Pcan), respectively. The 1H, 13C, and 15N nuclear magnetic resonance (NMR) chemical shifts of the system were monitored to investigate the structural geometry of the (CH3)2CHNH3 cations near phase I and II. Abrupt changes were observed in the chemical shifts near the TC, indicating a first-order phase transition from triclinic to orthorhombic symmetry. The results of this study imply that the structural environments around 1H, 13C, and 15N in the (CH3)2CHNH3 cations change significantly during phase II to I transition. Moreover, energy transfer was discussed based on NMR spin-lattice relaxation time data. This study indicates that the structural and physical properties of (CH3)2CHNH3CuCl3, an organic–inorganic material, make it a promising candidate for a wide range of potential applications.