分子价连接性指数中杂原子价点价计算新方法及应用

对分子价连接性指数中杂原子点价δ^v~i的计算方法进行了改进，提出了一种计算杂原子价点价δ^h~i的新方法，认为分子中某一杂原子i的价点价δ^h~i值不仅与它的价层电子数Z~i、最高主量子数n~i以及结合的氢原子数目h~i有关，还与它所在的族烽N~i、陷氢图中连接的其他原子的数目m~i以及杂化方式L~p有关。杂原子i的δ^h~i值与原子i的Pauling电负性具有相近的物理意义。用由δ^h~i构成的分子价连接性指数^nχ^h(n=0,1,2)研究了取代芳烃和烃衍生物的物理化学性质和生物活性，结果表明，^1χ^h比^1χ^v有显著的改善，计算值与实验值接近的程度更高。

A new method for calculatio valence delta of heteroatoms in molecular valence connectivity topological index and its application

The valence connection index δ^v~i is not suitable for the inorganic compounds that have complicated oxidation states (for example, S^2^- S^0S^2^+S^4^+S^6^+) and the organic compounds that include many types of heteroatoms such as F, Cl, Br, I, O, S, N, etc. In order to circumvent this problem, we defined the valence connection index δ^v~i of heteroatoms. It is discovered that the scope of vertex valence, δ^v~i is affected not only by the nature of the heteroatoms i (through the main quantum number n~i, the family number N~i, the number of Valence electrons Z~i, etc), but also by the conditions under which the bond is formed (through the binding hydrogen atom number h~i and other atom number m~i, hybridization mode Lp, etc). δ^v~i has explicit physical meanings, and shows linear relationship with Pauling electronegativities. By using the novel index of vertex, different hybridization states for the same atom can be distinguished. The improved molecular topological index ^nχ^h(n=0, 1, 2) is defined δ^h~i, the ^1χ^h of Cl~mSi(OR)n(m+n=4) halogeno-benzene and halogeno-phenol, ^nχ^h(n=0, 1, 2) of nitrogen- containing heterocycles and derivatives of alkanes. By using these ^nχ ^h's, good results have been obtained in predicting the physicochemical properties and biological activities (toxicity) of organic compounds. The results are much better than those of the topological ^1χ^v and ^1χ^- which are formed by δ^v~i and δ^-~i. It has been demonstrated that ^nχ^h is clear in physical meaning and easy to compute.