Topology and Group Theory-Tools for Determinating the Stereochemistry of Molecules

Modern Chemistry requires to handle complex stereochemical problems with a computer. Therefore, it is necessary to find a suitable way of modelling ensembles of molecules and their reactions. This kind of modelling must also consider dynamic structural properties of molecules. This cannot be described sufficiently by rigid models. Developing concepts and computer programs for describing stereochemical and constitutional regards simultanously requires an exact chemical nomenclature. Thus, a nomenclature must be found which is easily applicable and produces onlyasmall amount of data. Especially concerning stereochemistry this nomenclature must be applicable to atoms of any validity. No rules for special cases should be defined. For a definite description of ensembles of molecules our algorithms profit by topological and graph theoretical methods. Based on uncoloured molecular graphs, first the chemical nature of the vertices and finally by group theoretical aspects stereochemistry is introduced. This hierachical ordering allows to compare structural properties of chemical different molecules. Thus, for example reaction patterns of molecules can be transferred between chemical different but structural identical ensembles