Structural geometry of the layered perovskite-type (CH3CH2CH2NH3)2CuCl4 single crystal near phase transition temperatures

Chemical shifts and spin–lattice relaxation times are measured using 1H MAS NMR, 13C CP/MAS NMR, and 14N MAS NMR techniques to understand the structural geometry and dynamics of the alkyl and ammonium groups in layered perovskite (CH3CH2CH2NH3)2CuCl4. Each proton and carbon may be distinguished using MAS NMR. The 1H MAS NMR chemical shifts as a function of temperature showed a larger variation in the ammonium group than in the alkyl group, while the 1H relaxation time (T1ρ) for the ammonium groups was shorter than that of the alkyl group. The paramagnetic Cu2+ ions in the CH3CH2CH2NH3 cation were bonded with the inorganic layer through the N–H···Cl hydrogen bonds, and were paramagnetic, directly affecting the environment of 1H in NH3. The 13C T1ρ values for CH3 increased with temperature, a trend that has been observed in the alkyl group attached to the CH3CH2CH2NH3 cation because of an increased mobility toward its free end.