Combined first-principles computational and experimental multinuclear solid-state NMR investigation of amino acids.
13C, 14N, 15N, 17O, and 35Cl NMR parameters, including chemical shift tensors and quadrupolar tensors for 14N, 17O, and 35Cl, are calculated for the crystalline forms of various amino acids under periodic boundary conditions and complemented by experiment where necessary. The 13C shift tensors and 14N electric field gradient (EFG) tensors are in excellent agreement with experiment. Similarly, static 17O 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 17O NMR shielding parameters and the 35Cl quadrupolar parameters, respectively. Calculations using the two experimental structures for L-alanine have shown that, while the calculated isotropic chemical shift values of 13C and 15N are relatively insensitive to small differences in the experimental structure, the 17O shift is markedly affected.
Gervais
Christel
C
Laboratoire de Chimie de la Matière Condensée, UMR CNRS 7574, Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, France.
Dupree
Ray
R
Pike
Kevin J
KJ
Bonhomme
Christian
C
Profeta
Mickaël
M
Pickard
Chris J
CJ
Mauri
Francesco
F
D000596:Amino Acids / Q000737:chemistry*; D002247:Carbon Isotopes; D002713:Chlorine; D003198:Computer Simulation; D003460:Crystallization; D006860:Hydrogen Bonding; D007554:Isotopes; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010103:Oxygen Isotopes
D000596:Amino Acids; D002247:Carbon Isotopes; D007554:Isotopes; D010103:Oxygen Isotopes; D002713:Chlorine