Analysis of the structure, thermal, and molecular dynamics of organic–inorganic hybrid [NH 2 (CH 3 ) 2 ] 2 CdBr 4 crystal at phases IV, III, II, and I

Abstract A comprehensive understanding of the physicochemical properties of organic–inorganic hybrids is essential for their application. Therefore, a single crystal of [NH 2 (CH 3 ) 2 ] 2 CdBr 4 was grown; the crystal structure was monoclinic, and the phase transition temperatures for the four phases IV, III, II, and I were 383 K (T C1 ), 417 K (T C2 ), and 427 K (T C3 ). Furthermore, the chemical shifts caused by the local field around 1 H, 13 C, 14 N, and 113 Cd changed continuously with temperature, especially near T C1 , indicating that the local environment changes with temperature. Owing to the large change in 113 Cd chemical shifts, the coordination geometry of Br around Cd in the CdBr 4 tetrahedra changes near T C1 . Therefore, it is thought that Br plays a significant role in the N‒H···Br hydrogen bond. Finally, the spin-lattice relaxation time T 1ρ , representing the energy transfer around the 1 H and 13 C atoms of the cation, changed significantly with temperature. The activation energies obtained from the T 1ρ results were two times larger at high temperatures than at low temperatures. This study provides an understanding of the fundamental properties of organic–inorganic hybrid compounds to broaden their applications.