分子价连接性指数中杂原子价点价计算新方法及应用

A New Method for Calculation Valence Delta of Heteroatoms in Molecular Valence Connectivity Topological Index and Its Application

对分子价连接性指数中杂原子点价δvi 的计算方法进行了改进 ,提出了一种计算杂原子价点价δhi 的新方法 ,认为分子中某一杂原子i的价点价δhi 值不仅与它的价层电子数Zi、最高主量子数ni 以及结合的氢原子数目hi 有关 ,还与它所在的族数Ni、隐氢图中连接的其他原子的数目mi 以及杂化方式Lp有关。杂原子i的δhi 值与该原子i的Pauling电负性具有相近的物理意义。用由δhi 构成的分子价连接性指数nχh(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 ,1χh 比1χv有显著的改善 ,计算值与实验值接近的程度更高。

The valence connection index delta (v)(i) is not suitable for the inorganic compounds that have complicated oxidation states (for example, S2- S-0 S2+ S4+ S6+) 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 delta (v)(i) of heteroatoms. It is discovered that the scope of vertex valence, delta (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 L-p, etc). delta (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 (n)chi (h) (n = 0, 1, 2) is defined delta (v)(i) the (1)chi (h) of ClmSi(OR)(n) (m + n = 4) halogeno-benzene and halogeno-phenol, (n)chi (h) (n = 0, 1, 2) of nitrogen-containing heterocycles and derivatives of alkanes. By using these (n)chi (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 (1)chi (v) and (1)chi (-) which are formed by delta (v)(i) and delta (i) (-). It has been demonstrated that (n)chi (h) is clear in physical meaning and easy to compute.