Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid

Quimica nova

Irshaidat, Tareq¹ 

[1] Al-Hussein Bin Talal University, Ma'an

关键词: amino acid;    anthranilic acid;    zwitterion;    hydrogen bond;    NBO.;   

DOI  :  10.5935/0100-4042.20140246

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput.2012, 8, 2293) illustrated that beryllium ions are capable of significantly modulating (changing) the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+, AlF21+, AlF2+, and Al3+) were investigated. Several aspects were addressed: natural bond orbitals, including second order perturbation analysis of intra-molecular charge delocalization and the natural population analysis atomic charges; molecular geometries; selected infrared stretching frequencies (C–N, C–O, and N–H), and selected 1H-NMR chemical shifts. The data illustrate that this interaction can weaken the H–O bond and goes beyond strengthening the intra-molecular hydrogen bond (N...H–O) to cause a spontaneous transfer of the proton to the nitrogen atom in five cases generating zwitterion structures. Many new features are observed. Most importantly, the zwitterion structures include a stabilizing hydrogen bond (N–H...O) that varies in relative strength according to the Lewis acid. These findings explain the experimental observations of α-amino acids (for example: J. Am. Chem. Soc.2001, 123, 3577) and are the first reported fundamental electronic structure characterization of β-amino acids in zwitterion form.

【 授权许可】

CC BY