Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (09): 2051-2058.doi: 10.3866/PKU.WHXB20110930


Accurate Predictions of the NMR Parameters in Organic and Biological Crystallines

HE Rui, JIAO Yan-Hua, LIANG Yuan-Yuan, CHEN Can-Yu   

  1. Research Center of Biomedicine and Health, Hangzhou Normal University, Hangzhou 311121, P. R. China
  • Received:2011-06-03 Revised:2011-07-08 Published:2011-08-26
  • Contact: HE Rui
  • Supported by:

    The project was supported by the Science and Technology Development Program of Hangzhou, China (20091133B09), Zhejiang Provincial Medicine & Health Research Fund, China (2009A158), and Zhejiang Provincial PublicWelfare Application Project of China (2010C33132).

Abstract: Theoretical predictions are helpful for the spectroscopic identification of complicated organic and biological systems. For nuclear magnetic resonance (NMR) parameters, however, the chemical shift and quadrupole coupling constant (QCC) of the solid crystals are considerably affected by hydrogen bonding and van der Waals interactions from neighboring molecules and the crystal lattice leading to significant spectroscopic differences compared to isolated monomer molecules. Therefore, it is necessary to take these two factors into account for the precise predictions of chemical shifts and QCCs of solid crystals. L-alanylglycine dipeptide and nitrobenzene were selected as model crystals to demonstrate these effects. Here, the chemical shielding (CS) and QCC data were calculated based on the periodic structure model. The incorporation of intermolecular hydrogen bonding and crystal lattice effects by periodic models was found to be crucial in obtaining reliable predictions of CS and QCC values and rendering more explicit spectroscopic assignments for solid organic and biological systems.

Key words: NMR, Quadruple coupling constant, DFT calculation, Hydrogen bonding interaction