A Shape Index from Molecular Graphs

Abstract

Abstract A numerical index of molecular shape has been derived from the graph of the non‐hydrogen molecular skeleton. The index is based on the count of 2‐bond fragments in a graph relative to the maximum number possible in the isomeric star graph and the minimum number in the isomeric linear graph. In this initial study all non‐hydrogen atoms and all bonds are considered equal. The 2 κ index describes the molecular shape in relationship to the star and linear graph and is normalized to the number of atoms. Applications are presented for shape similarity estimation, cavity filling ability and QSAR analyses.