Analysis of the Structure, Thermal, and Molecular Dynamics of Organic-Inorganic Hybrid Crystal at Phases IV, III, II, and I: [NH2(CH3)2]2CdBr4

Sun Ha Kim; Yong Lak Joo; Ae Ran Lim

doi:10.1021/acsomega.3c05963

Analysis of the Structure, Thermal, and Molecular Dynamics of Organic-Inorganic Hybrid Crystal at Phases IV, III, II, and I: [NH₂(CH₃)₂]₂CdBr₄

ACS Omega. 2023 Sep 8;8(37):34180-34187. doi: 10.1021/acsomega.3c05963. eCollection 2023 Sep 19.

Authors

Sun Ha Kim^{1

2}, Yong Lak Joo³, Ae Ran Lim^{4

5}

Affiliations

¹ Seoul Western Center, Korea Basic Science Institute, Seoul 03759, Korea.
² Department of Chemistry, Kyungpook National University, Daegu 41566, Korea.
³ School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States.
⁴ Graduate School of Carbon Convergence Engineering, Jeonju University, Jeonju 55069, Korea.
⁵ Department of Science Education, Jeonju University, Jeonju 55069, Korea.

Abstract

A comprehensive understanding of the physicochemical properties of organic-inorganic hybrids is essential for their solid-state lighting applications. Therefore, a single crystal of [NH₂(CH₃)₂]₂CdBr₄ 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 ¹H, ¹³C, ¹⁴N, and ¹¹³Cd changed continuously with temperature, especially near T_C1, indicating that the local environment changes with temperature. Owing to the large change in ¹¹³Cd chemical shifts, the coordination geometry of Br around Cd in the CdBr₄ 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 ¹H and ¹³C 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.