CHARACTERIZATION OF MOLECULAR BRANCHING
CHARACTERIZATION OF MOLECULAR BRANCHING
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DOI：
10.1021/ja00856a001
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发表时间：
1975-01-01
影响因子：
15
通讯作者：
RANDIC, M
中科院分区：
文献类型：
--
作者：
RANDIC, M
考虑了分子分支的理论表征。基于分子图边缘类型的区分，对同源序列的成员进行了排序，并对单个结构进行了数值索引。特别考虑了具有8个或更少碳原子的线性和支链烷烃，并建立了衍生的支链指数和性质之间的相关性，这主要取决于分子的大小和形状。该指标与实证指标Kováts也有较好的一致性。该方法揭示了同分异构体之间的一些内在关系，这些关系可以追溯到连通性和分子拓扑结构。它指出，在某些情况下，如果精度上的牺牲是可以容忍的，并由所指出的相互关系的重要性来补偿，则实验推导出的表征分子性质的常数的数目会大大减少。对安托万方程经验常数的分析说明了这一点。一些分子性质取决于分子形状，并在一系列同源化合物中有规律地变化。分子骨架的分支程度是其中的关键因素。碳氢化合物的沸点和色谱研究得到的保留体积或保留时间是典型的这种相关性。相互作用的大小直接关系到分支的程度，以及分子的大小。因此，分子拓扑结构在表征这些实验量时是很重要的。如果我们能够定义所涉及的直观概念，那么开发一种可以定量表征分子分支程度的程序是可取的。没有一致的意见
A theoretical characterization of molecular branching is considered. Members of homologous series are ordered in a sequence and a numerical index is assigned to individual structures based on a differentiation of edge types of molecular graphs. Linear and branched alkanes having eight or less carbon atoms have been consideredin particular and correlations between the derived branching index and properties which critically depend on molecular size and shape are established. The proposed index is also in satisfactory agreement with the empirical index of Kováts. The approachreveals some inherent re-lationships between isomers which can be traced to connectivity and molecular topology. It points, in some cases, to a considerable reduction in the number of experimentally deduced constants characterizing molecular properties, provided a sacrifice in precision can be tolerated and is compensated for by the significance of the indicated inter-relations. This point is illustrated on an analysis of the empirical constants of the Antoine equation.Some molecular properties depend upon molecular shape and vary regularly within a series of homologous com-pounds. The degree of branching of the molecular skeleton is the critical factorinvolved. Boiling points of hydrocar-bons and the retention volumes or retention times obtained from chromatographic studies are typical of this kind of correlation. The magnitude of interaction is directly related to degree of branching, as well as molecular size. Thus the molecular topology is important in characterizing some of these experimental quantities. It would be desirable to de-velop a procedure which can quantitatively characterize the degree of molecularbranching, providing we are able to de-fine the intuitive concept involved. There is no unanimity of