Discussed are the substructures (subgraphs) of imaginary transition structures that provide an effective approach to the characterization of organic reactions. A comparison of conventional methods and this method is presented. (CW)

Discussed is an extension of the conventional method for studying the organometallic chemistry of transition metals that may be useful to show how the various existing types of low-valence complexes can be constructed. This method allows students to design new types of complexes that may still be nonexistent. (CW)