NMR和分子力学法研究溶液中有机分子结构

在分子力学能量优化项中加入由ＮＭＲ实验得到的几何参数二面角（相应于~３Ｊ_（ＨＨ）耦合常数）及质子间距所构造的约束函数，使分子力学计算得到的能量极小点的分子构象，其耦合常数（~３Ｊ_（ＨＨ））及质子间距同ＮＭＲ实验结果相符合。文中以（±）－３－（４＇－甲苯基）－１－氮杂双环［２．２．２］－３－辛醇为例，采用自编的ＮＭＲ参数约束的分子力学计算程序ＭＭ２ＮＪ对其构象进行了计算。所得结果与Ｘ射线衍射法比较，有较好的一致性

The Studies of Three-Dimensional Solution Structure of Organic Compounds by Combination NMR Techniques with Molecular Mechanics

It is proposed that three-dimensional structures of organic compounds in solution are elucidated by combining NMR with molecular mechanics (MM2). In the structural calculation of MM2 the restrained terms are considered which are constructed with proton internuclear distances and dihedrals obtained from NMR experiments. So the calculated structure is a conformation which lies in energy minimum and is confirmed by NMR experiments. As an examle of the method, the three-dimensional structure of organic compound (±)-3-(4-methylphenyl)-1-azabi-cyclo[2. 2. 2]-3-octanol is calculated by using our program MM2NJ. The results show that the structure extracted from NMR data by combining with MM2 calculation is in quite good agreement with that one obtained from X-ray diffraction measurement.