Cation dynamics by H and C MAS NMR in hybrid organic-inorganic (CHCHNH)CuCl.

To understand the dynamics of the cation in layered perovskite-type (CHCHNH)CuCl, the temperature-dependent chemical shifts and spin-lattice relaxation times in the rotating frame have been measured using H magic angle spinning nuclear magnetic resonance (MAS NMR) and C cross-polarization (CP)/MAS NMR techniques. Each proton and carbon in the (CHCHNH) cation is distinguished in MAS NMR spectra. The Bloembergen-Purcell-Pound (BPP) curves for H in CHCH and NH, and for the C in CH and CH are revealed to have minima at low temperatures. This implies that the curves represent the CH and NH rotational motions. The amplitude of the cationic motion is enhanced at the C-end, that is, the N-end of the organic cation is fixed to the inorganic layer through N-H⋯Cl hydrogen bonds, and becomes short with larger-amplitude molecular motions.