Concepts of Trapping Topologically by Shell Molecules

Concepts of the synthesis of shell topological compounds, which consist of a guest molecule (or molecules) trapped by a host molecule with a spacial, egg shell-like structure are discussed. Generally, both constructing the shell molecule in the presence of a guest molecule and constructing the guest molecule in the presence of the shell (host) are ways to “shell” topological compounds. The preparation of shell molecules may consist of the completion of “preshell” molecules or of obtaining cascade branched oligomers and polymers. Cyclodextrins and substances like triquinance are considered to play a role in preshell molecules. Shell molecules may also be obtained by polyreaction of a monomer of the XRY_n type, which results in a cascade branched molecule of shell structure (spherical form). When the polyreaction is continued, the cascade branched molecule becomes a “cast” one. It is theoretically possible to enclose a guest molecule inside the shell during the cascade branching process if there is a good solvent (of high expansion coefficient value) in respect to the growing branches. A spacially developed molecule of both “empty” and “cast” structure may be obtained also by the known “step by step” cascade branching process which involves, for instance, a repeated cyanoethylation-reduction reaction.