Proton NMR relaxation studies of solid L-alaninamide

The molecular dynamics of solid L-alaninamide were studied by proton spin lattice relaxation times in the laboratory and rotating frames, and second moment measurements over temperature range of 100 to 350 K. The methyl group tunnelling was observed below 130 K. The rotational motions of both methyl and amino groups were responsible for spin-lattice relaxation at higher temperature. Three reductions of dipolar second moment were observed over the temperature range. The rotations of methyl and amino groups attributed to the first and second reductions of the second moment at 120 and 240 K. The third reduction above 340 K is due to the molecular motion occurred at crystal melting.