Ionic dynamics of the cation in organic–inorganic hybrid compound (CH<sub>3</sub>NH<sub>3</sub>)<sub>2</sub>MCl<sub>4</sub>(M = Cu and Zn) by<sup>1</sup>H MAS NMR,<sup>13</sup>C CP MAS NMR, and<sup>14</sup>N NMR
RSC advances