有机和生物晶体固态核磁共振参数的准确预测(英文)  

Accurate Predictions of the NMR Parameters in Organic and Biological Crystallines

作　　者：何睿[1] 焦艳华[1] 梁媛媛[1] 陈灿玉 

机构地区：[1]杭州师范大学生物医药与健康研究中心,杭州311121

出　　处：《物理化学学报》2011年第9期2051-2058,共8页Acta Physico-Chimica Sinica

基　　金：supported by the Science and Technology Development Program of Hangzhou,China (20091133B09);Zhejiang Provincial Medicine & Health Research Fund,China (2009A158);Zhejiang Provincial Public Welfare Application Project of China (2010C33132)~~

摘　　要：理论计算有助于复杂的有机和生物系统光谱的鉴定.对于核磁共振光谱,固体结晶中的化学位移和四极耦合常数(QCC)受到邻近的分子和晶格的氢键和范德华作用较大的影响,从而显示出与气态单体分子不同的NMR参数.因此,在固体晶体NMR参数的理论计算中有必要将氢键和范德华作用这两个因素考虑进来.基于周期性方法,本文采用L-Ala-Gly二肽和硝基苯晶体作为模型体系来考察该方法计算NMR参数的精度.研究结果显示周期结构模型能够将分子间的氢键和范德华作用考虑进来,得到的化学位移和QCC值明显优于传统的单分子模型和超分子模型得到的结果,采用该方法计算的结果能够重现NMR实验结果.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.

关 键 词：核磁共振 四极耦合常数 密度泛函理论计算 氢键作用 

分 类 号：O621.1[理学—有机化学]