Chemical information theory: Structural aspects

Abstract

Abstract Information is a concept of no less importance than matter or energy. Information has been de- scribed as a measure of the variety in a given system. We review several of the indices of molecular information, including those indices related to molecular composition, molecular symmetry, graph automorphism, graph coloring, and connectivity as measured by adjacency, path lengths, and cy- clicity. Electronic information indices include those related to the division of electronic structures into u and ?r bond spaces, core and valence spaces, and lone pair, bond pair, or molecular fragment spaces. General molecular information indices have been formed by combining two or more specific indices. Information theoretic indices haye been supplied to problems of isomer discrimination, classification of molecular complexity, and structure-property and structure-activity correlations. The potential for further applications is great. Introduction The concept of information appears to be one of the most fundamental con- ceptions in the science of the 20th century, a concept of no less importance than that of matter or energy. This assertion follows from the very definitions of in- formation. According to Wiener