COMPARATIVE-STUDY OF MOLECULAR DESCRIPTORS DERIVED FROM THE DISTANCE MATRIX

A comparative study of 10 distance indices derived from the distance matrix either in the graph-theoretical (topological) form or in the geometric (topographic) form is carried out. They are partitioned into five topological indices and five topographic indices. The adjective topological or topographic indicates which matrix each family of distance indices has originated from. All five topological indices have been known in the literature, while four out of five topographic indices are introduced in this work. Only the 3-D Wiener number has been proposed earlier. Most of distance indices are found to be intercorrelated, i.e., they contain similar structural information. Only 2-J and 3-J indices did not intercorrelate with any other distance index but themselves. The three most accurate structure-property models for predicting boiling points of alkanes are based on the connectivity index-chi, its variant chi' (= N(chi)), and on the topological distance index 2-TI. It is unclear at present why the 3-D distance indices have produced inferior structure-boiling point models in comparison with models based on the 2-D distance indices and connectivity indices.