Structure and dynamics in L-leucinamide

An account is given of the X-ray structure, the solid-state carbon spectra and carbon and proton relaxation times of solid crystalline L-leucinamide. The temperature dependence of proton spin lattice relaxation rates in the laboratory and rotating frames as well as transverse and dipolar relaxation in the have been measured. The nature and origins of the dipolar relaxation, which is bi-exponential is discussed in terms spin temperature equilibration and the motion of the amino groups. Relaxation times have also been measured using fast field cycling NMR and the interpretation of the results at low fields, where high field approximation is no longer valid, is considered. Comparison of the NMR results with the crystal structure allow a self consistent model in terms of amino and methyl group motion to be developed.