“…In contrast, purity and structural uniformity are harder to maintain in the divergent approach, because the number of reactions that must be completed at each step of growth increases exponentially requiring large excesses of reagents, but the process is better suited not only for syntheses on a larger scale but also for the preparation of high-generation dendrimers. Although the majority of the dendrimers prepared to-date have been built of covalent bonds (3,10), many noncovalent dendrimers (3,11) have also been prepared by a variety of selfassembly processes involving, for example, hydrogen bonding (12) or supramolecular coordination chemistry (13).…”