有机化合物中碳原子化学环境的分类

CLASSIFICATION OF CHEMICAL ENVIRONMENTS OF CARBON ATOMS IN ORGANIC COMPOUNDS

进行碳－１３ＮＭＲ波谱模拟的一种常用方法为线性回归，其数学模型则由已知结构所测得的化学位来建立。显然，每一数学模型仅可用于某种相似的化学环境。因此，为了进行化学环境的分类，本文提出权重层次位图法和分子连接性指数法两种方法以进行一些参数的计算，同时采用多元分析手段，如主成分分析和聚类分析，以进行多维空间数据点的显示，所得结果比较满意，从而可为碳－１３波谱模拟中回归方程的选择提供理论依据。

One approach to C-13 NMR spectrum simulation involes the construction and use of linear models relating numerically encoded structural features to observed C-13 chemical shifts. Evidently, a characteristic of the models is that each is applicable only to atom similar to those used to determine the models. Therefore, in present study, two algorithms, weighted bit map and connectivity,for calculation of structural similarity for classification of chemical environments were proposed. For the classification of chemical environments of a carbon atom, the multivariate analysis approaches were used for determing the relationships among the multidimensional points with satisfactory results. Based on the results, if a structure is known, the most suitable model (if any) for the simulation can be selected.