Topological information content and chemical reactions

The difference of the topological information content of two reacting molecules and that of their reaction products is calculated for several topological types of chemical reactions, illustrating the influence of the structure of the reagents and of the reaction product. It is shown that the change in the topological information content in a chemical reaction can be positive as well as negative, depending on the way the reagents approach each other and thus on the reaction product formed. A quantitative measure of structural specificity is introduced.