Structure and dynamics of L-selenomethionine in the solid state

L-selenomethionine 1 crystallizes in P2(1) space group with two molecules in the asymmetric unit. Solid-state NMR spectroscopy is used for searching of structure and dynamics of 1 in the crystal lattice. The distinct molecular motion of side chains for A and B molecules of 1 is apparent from measurements of relaxation parameters (H-1 Tau(1 rho), C-13 T-1) and analysis of CSA data (2D-PASS experiment). The C-13 delta(ii) and Se-77 delta(ii) parameters are correlated with theoretical shielding parameters obtained by means DFT GIAO calculations. Attempt to explain the mechanism of phase transition of crystals of 1 at 313K is presented.