化学
二面角
从头算
化学位移
洋葱
计算化学
糖苷键
另一个
溶剂效应
碳-13核磁共振
双糖
物理化学
溶剂
氢键
分子
立体化学
有机化学
酶
作者
Mohsen Tafazzoli,Mina Ghiasi
标识
DOI:10.1016/j.carbpol.2009.02.020
摘要
The anomeric carbon chemical shifts of α-, β- and γ-cyclodextrin in solution were studied experimentally and theoretically by NMR and two-layer ONIOM2 (B3LYP/6-31G*-GIAO: HF/6-31G*-GIAO) variant. The dependence between the anomeric carbon chemical shift and the glycosidic bond φ and ψ dihedral angles in d-Glcp-d-Glcp disaccharides with and (1 → 4) linkages in α-configurations were computed by Gauge-Including Atomic Orbital (GIAO) ab initio and ONIOM in water solvent using PCM methods. Complete chemical shift surfaces versus φ and ψ for this disaccharide were computed. We also present empirical formulas of the form 13C δ = f(φ, ψ) obtained by fitting the ab initio data to trigonometric series expansions. The results are consistent with experimental observations and show the applicability of chemical shift surfaces in the conformational behavior of oligosaccharides.
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