波谱学杂志2020，Vol.37Issue(1)：67-75,中插3-中插6,13.DOI:10.11938/cjmr20192726
晶体学辅助的2-吡啶甲酸固体13C化学位移理论计算归属(英文)
13C Chemical Shift Assignment of Solid 2-Picolinic Acid by DFT/Crystallography Integrated Approach
摘要
Abstract
The tautomerism of organic molecules is widely observed in solution. While for solid organic chemicals, molecules often exist in the most stable tautomeric form. 2-Picolinic acid (PCA) is a very rare case which contains both the neutral molecules and zwitterions in the same crystal structure. Chemical shift assignment for PCA by experimental approach, e.g., 2D NMR methods, is extremely time consuming because the 1H spin-lattice relaxation time (T1) is too long. Density functional theory (DFT) calculation, especially using a periodic model, is an alternative protocol to fix this issue. However, the original crystal structure of PCA cannot be submitted directly for the calculation task due to the proton positional disorder. In this contribution, a virtual structure was constructed via crystallography approach. Theoretical 13C chemical shifts were obtained basing on this virtual model, which are consistent with the experimental values. Also, both neutral PCA and zwitterion demonstrated their featured chemical shifts, such information can be utilized to analyze the molecular states of PCA in its crystalline complexes.关键词
分子互变异构/固体核磁共振/DFT计算/两性离子/单晶X射线衍射Key words
molecular tautomerism/solid-state NMR/DFT calculation/zwitterion/single crystal X-ray diffraction分类
数理科学引用本文复制引用
张之杰,李端秀,罗春,仇汝臣,邓宗武,张海禄..晶体学辅助的2-吡啶甲酸固体13C化学位移理论计算归属(英文)[J].波谱学杂志,2020,37(1):67-75,中插3-中插6,13.基金项目
the National Natural Science Foundation of China (21673279) （21673279）
the Youth Innovation Promotion Association of CAS (2012242). （2012242）
