Analysis of the Structure, Thermal, and Molecular Dynamics of Organic-Inorganic Hybrid Crystal at Phases IV, III, II, and I: [NH 2 (CH 3 ) 2 ] 2 CdBr 4 .

A comprehensive understanding of the physicochemical properties of organic-inorganic hybrids is essential for their solid-state lighting applications. 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 proposed 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.
Competing Interests: The authors declare no competing financial interest.
(© 2023 The Authors. Published by American Chemical Society.)