DESIGN OF TOPOLOGICAL INDICES. PART 27. SZEGED MATRIX FOR VERTEX- AND EDGE-WEIGHTED MOLECULAR GRAPHS AS A SOURCE OF STRUCTURAL DESCRIPTORS FOR QSAR MODELS

摘要

An important number of quantitative structure-property relationships (QSPR) and quantitative structure-activity relationships (QSAR) are obtained with structural descriptors derived from molecular graph matrices. These descriptors can be used also in similarity and diversity assessment, database mining, and in the virtual screening of combinatorial libraries. Graph distances represent the basis for the definition of new molecular matrices, such as the reciprocal distance RD, edge Szeged Sz_e path Szeged Sz_p, distance-valency Dval, distance complement DC, complementary distance CD, reciprocal complementary distance RCD, and reverse Wiener RW matrices. In this study we extend the edge Szeged matrix Sz_e to vertex- and edge-weighted molecular graphs representing organic molecules containing heteroatoms and/or multiple bonds. Using five new approaches for the calculation of atom and bond parameters in weighted molecular graphs, the edge Szeged matrix Sz_e is employed to compute descriptors tested in QSAR models of phenols toxicity.