Combined first-principles computational and experimental multinuclear solid-state NMR investigation of amino acids

C-13, N-14, N-15, O-17, and Cl-35 NMR parameters, including chemical shift tensors and quadrupolar tensors for N-14, O-17, and Cl-35, are calculated for the crystalline forms of various amino acids under periodic boundary conditions and complemented by experiment where necessary. The C-13 shift tensors and N-14 electric field gradient (EFG) tensors are in excellent agreement with experiment. Similarly, static O-17 NMR spectra could be precisely simulated using the calculation of the full chemical shift (CS) tensors and their relative orientation with the EFG tensors. This study allows correlations to be found between hydrogen bonding in the crystal structures and the O-17 NMR shielding parameters and the Cl-35 quadrupolar parameters, respectively. Calculations using the two experimental structures for L-alanine have shown that, while the calculated isotropic chemical shift values of C-13 and N-15 are relatively insensitive to small differences in the experimental structure, the O-17 shift is markedly affected.