ABSTRACT
The enumeration of isomeric species represents the first overt ap plication of graph-theoretical and combinational techniques to the solu tion of a problem of chemical interest. The history of the development of isomer enumeration techniques reveals a strong interaction of math ematicians and chemists, and provides a textbook example of interdisiplinary collaboration. Althcmgh of much more ancient vintage [66], the conrept of isomerism was first formaUy defined by Berzelius [67] in 1830. According to Berzelius, isomers were compounds, "possessing the same chemical constitution and molecular weight but differing properties.” The earliest systematic exposition of the theory of structure is contained in Kekuld’s famous Lehrbuch der Ovganischen Chemie [68] of 1861. The role of structural isomerism was further elucidated in 1862 by Butlerov, who succeeded in obtaining the number of isomers in the chloro-substituted methanes [69]. Stereoisomerism was initially recognized by Pasteur [70], though its ubiquity in chemistry was first pointed out in the works of Le Bel [71] and van’t Hoff [72]. The latter worker showed that the theoretical number of steremsomers formed from a molecule containing n asymmet ric carbon atoms would be 2” . Further details on the evolution of the concept of isomerism are to be found in the review by Rouvray [74].
