Ionic dynamics of the cation in organic-inorganic hybrid compound (CH 3 NH 3 ) 2 MCl 4 (M = Cu and Zn) by 1 H MAS NMR, 13 C CP MAS NMR, and 14 N NMR.

The ionic dynamics of (CH 3 NH 3 ) 2 MCl 4 (M = Cu, Zn) by 1 H magic-angle spinning (MAS) nuclear magnetic resonance (NMR), 13 C cross-polarization (CP) MAS NMR, and 14 N NMR are investigated as a function of temperature with a focus on the role of the CH 3 NH 3 + cation. The molecular motions in (CH 3 NH 3 ) 2 MCl 4 are also discussed based on the 1 H spin-lattice relaxation time in the rotating coordinate frame T 1ρ . From the 1 H T 1ρ results, the activation energies for the tumbling motion of 1 H for CH 3 and NH 3 were similar, and the uniaxial rotations occurred within a large temperature range. The molecular motions for 13 C and 14 N of the main chain in the CH 3 NH 3 + cation were rigid, whereas those for 1 H of the side chain in the CH 3 NH 3 + cation were very free at high temperatures. T 1ρ provides insight into the changes in the cation reorientation rates induced by heating at high temperatures.