A novel topological index for QSPR QSAR study of organic compounds

A novel topological index Xu based on the adjacency matrix A and distance m atrix D was derived in this paper. The index, which was very easy to calcul ate and also had good discrimination between isomeric alkanes, was highly c orrelated with the selected physicochemical properties of alkanes, and most properties were well modeled (r > 0.99). Moreover, it was also convenient to extend the Xu index to the multipolybonds, heteroatom - containing compo unds using the relative ratio of bond length to C-C bond in place of the ad jacent topological distance and the valence delta(i) instead of the degree of vertex v(i). The index also produced a fair regression for the heat capa city of olefins and the toxicity and hydrophobicity parameters of alkanols (r > 0.99). The calculated values were in good agreement with experimental data. The results suggested that the proposed index with fairly high correl ation ability and structural selectivity promised to be a useful parameter in QSPR/PSAR research.