Comprehensive study of organic-inorganic hybrid [N(C

The compound [N(C2H5)4]2CdBr4, an organic-inorganic hybrid compound, has garnered attention for its potential applications across various fields. In this study, single crystals of [N(C2H5)4]2CdBr4 were grown, and two distinct phase transition temperatures were identified: approximately 232 K (T C1) and 476 K (T C2). Single-crystal X-ray diffraction analysis at 300 K revealed a tetragonal structure belonging to the space group P4̄21 m. The thermal properties of the material were also briefly examined. Interestingly, while the 1H NMR chemical shifts exhibited minimal variation around T C1, the 13C NMR spectra showed a noticeable change in the number of peaks, suggesting a structural phase transition. These observations indicate that the crystal retains a tetragonal structure above T C1 but transitions to a phase with lower symmetry below this temperature. Furthermore, 113Cd NMR chemical shifts showed a significantly more pronounced change near T C1 compared to the shifts observed for 1H and 13C. This behavior reflects alterations in the local electronic environment around the Cd2+ ions, implying reconfiguration of the surrounding atomic framework. Additionally, the spin-lattice relaxation times for 1H and 13C, which are related to molecular motion, were nearly identical for both CH2 and CH3 groups in [N(C2H5)4] cations. The phase transition observed at T C1 is thus attributed to substantial structural rearrangements, particularly involving changes in atomic coordinates and the rotation of the CdBr4 2- tetrahedra.