Dendrimers as reactive modules for the synthesis of new structure-controlled, higher-complexity megamers*

Dendrimers are macromolecular, nanoscale objects that are widely recognized as precise, mathematically defined, covalent core-shell assemblies. As such, they are composed of quantized numbers of atoms, monomers, and terminal functional groups relative to the respective shell levels (generations) surrounding their cores. Dendrimers have been referred to as molecular-level analogs of atoms. This perspective arises from their potential to function as precise macromolecular tectons (modules), suitable for the synthesis of structure-controlled complexity beyond dendrimers. We have termed this major new class of generic structures “megamers”. Our group has now synthesized such “megamer complexity” in the form of both covalent and supra-macromolecular dendri-catenanes, dendri-macrocycles, dendriclefts, and dendri-clusters. The covalent dendri-cluster subset of megamers has been coined “core-shell tecto(dendrimers)”. New mathematically defined, covalent bonding rules for tecto(dendrimer) formation are consistent with sterically induced stoichiometry (SIS) predictions and have been verified experimentally.