Organic-inorganic hybrid [NH 3 (CH 2 ) 6 NH 3 ]ZnBr 4 crystal: structural characterization, phase transitions, thermal properties, and structural dynamics.

Organic-inorganic hybrid [NH 3 (CH 2 ) 6 NH 3 ]ZnBr 4 crystals were prepared by slow evaporation; the crystals had a monoclinic structure with space group P 2 1 / c and lattice constants a = 7.7833 Å, b = 14.5312 Å, c = 13.2396 Å, β = 90.8650°, and Z = 4. They underwent two phase transitions, at 370 K ( T C1 ) and 430 K ( T C2 ), as confirmed by powder X-ray diffraction patterns at various temperatures; the crystals were stable up to 600 K. The nuclear magnetic resonance spectra, obtained using the magic-angle spinning method, demonstrated changes in the 1 H and 13 C chemical shifts were observed near T C1 , indicating changing structural environments around 1 H and 13 C. The spin-lattice relaxation time, T 1ρ , increased rapidly near T C1 suggesting very large energy transfer, as indicated by a large thermal displacement around the 13 C atoms of the cation. However, the environments of 1 H, 14 N, and C1 located close to NH 3 in the [NH 3 (CH 2 ) 6 NH 3 ] cation did not influence it significantly, indicating a minor change in the N-H⋯Br hydrogen bond with the coordination geometry of the ZnBr 4 anion. We believe that the information on the physiochemical properties and thermal stability of [NH 3 (CH 2 ) 6 NH 3 ]ZnBr 4 , as discussed in this study, would be key to exploring its application in stable, environment friendly solar cells.