同分异构物分子结构与性能间的定量关系 1.多环芳烃中直链结构长度的优势

QUANTITATIVE STRUCTURE PROPERTY RELATIONSHIP IN ISOMERIC COMPOUNDS.I.PREDOMINNACE OF LENGHT OF STRAIGHT CHAIN IN POLYCYCLIC AROMATIC HYDROCARBONS

本文研究了多环烃异构物的分子轨道能量与电子活动性能的关系,包括各种并苯、联苯类异构物的分子轨道能级以及电子光谱等有关性能。每组异构物中,与最高占有分子轨道能级E_1及直接相关的性能以最长直链物为最低级限,带有侧位环的异构物则依侧位环数目递增,与E_(-1)及其直接相关性能,则以最长直链物为最高极限,依直环数的缩减而递减。各组异构物之间,性能～环数图线上形成的同系列曲线和等直环线都表明分子中直链的长度是主要因素。

In this paper it has been shown that for the electronic properties of every group of isomeric aromatic hydrocarbons, the length of the chain of rings arranged straightly is the predominant structural factor. For energy of the highest occupied molecular orbitals E_1 and related properties, such as transition energy △E_1, ionization potential I_p. the isomer with all its rings straightly arranged is the lowest limit for the property considered. While the isomers with 1, 2, 3,…lateral rings are lifted step by step in property value. On the other hand, the reciprocal of energy difference, e. g. electronic absorption wavelength is reversed in the order.For energy of the lowest vacant orbitals E_ and properties directly depending on it, such as electron affinity A_E, methyl affinity A_(Me), the isomeric compound with longest straight ringchain is the highest limit, while those with shorter chains decrease in the property step by step accordingly.Among variuus groups of isomeric compounds, the ones with the same number and same arrangement of lateral rings but with regular increase of straight rings form a simple homologous curve. It has been found that the curves for different sets of lateral structure are regularly spaced and almost parallel. These constitute a set of homologous lines.The lines connecting compounds of the same length of straight chain in various groups form a set of roughly parallel lines with very small slope. namely, a series of lines of equal straight rings.By means of assigning a constant equivalent value for each lateral ring in all the isomers, it has been shown that the extended homologous equation can be used to express the homologous curves by a straight line, P=a+b(1/2)^(2/(m-jk)) were m is the total number aromatic rings, j is the number of the lateral rings, and k a constant with the value of 1.1 for every laterally fused benzene ring and 2.2 for each lateral phenyl group.