A Molecular Picture of the Adsorption of Glycine in Mesoporous Silica through NMR Experiments Combined with DFT-D Calculations

作者：Folliet Nicolas; Gervais Christel^*; Costa Dominique; Laurent Guillaume; Babonneau Florence; Stievano Lorenzo; Lambert Jean Francois; Tielens Frederik

来源：Journal of Physical Chemistry C, 2013, 117(8): 4104-4114.

DOI：10.1021/jp312195a

The adsorption behavior of the amino acid glycine in mesoporous silica has been investigated using a combination of quantum chemical calculations and NMR spectroscopy experiments. Glycine adsorption on two representative sites of an amorphous silica surface, vicinal silanols and a silanol nest, was investigated by DFT-D. The effect of water coadsorption on the energetics of adsorption and NMR shifts was characterized. It was found that the silanol nest is a more favorable site for glycine adsorption due to a local increased H-bond density. Co-adsorption with water is also favored, especially a water molecule between a SiOH and the ammonium moiety. NMR chemical shifts computed on these models fall into the observed C-13 and N-15 experimental range, suggesting that the presence of different energetically comparable adsorption configurations cannot be excluded.

• 出版日期2013-2-28