Non-Covalent Synthesis of Metallodendrimers

Abstract

The field of dendrimers has undergone an explosive growth since the first dendritic structures were reported two decades ago. These three-dimensional, highly branched macromolecules have attracted interest from such diverse areas as polymeric, organic, inorganic, biomedical, theoretical, and physical chemistry. Future applications were already hypothesized from the early days of dendrimer research. From an application point of view, the incorporation of a range of metals into the dendritic framework is of particular interest. The resulting metallodendrimers might be applied in fields such as catalysis, sensors, medical diagnosis, light-harvesting devices, and nanoparticles. In this chapter, metallodendrimers are discussed in which the metals are essential for maintaining the dendritic structure. This means that all the dendrimers described have been assembled non-covalently using coordination chemistry. Although this restriction narrows the metallodendrimer field significantly, there is still an enormous variety in the architecture of reported non-covalent metallodendrimers. Where possible, emphasis is placed on the characterization methods and specific behavior of the dendrimers, because characterization is of utmost importance in establishing their often complicated three-dimensional structure. Finally, we have emphasized properties that may lead to future applications.

Dendrimers and supramolecular chemistry

“…2) for the assembly. The topic of selfassembly of dendrimers has been thoroughly reviewed (11,(17)(18)(19)(20)(21)(22)(23)(24).…”

Second‐Generation Supramolecular Dendrimer with a Defined Structure due to Orthogonal Binding

“…This problem can be solved if different and orthogonal recognition events are chosen for each generation. In addition to hydrogen bonds, coordinative bond formation9, 10 can also be used for the assembly of dendrimers or betaines 11. A combination of coordinative bond formation for the core and hydrogen bonding for the next generation has been demonstrated by Hirsch and co‐workers 14…”

“…[8] Whole dendrons can also be connected by reversible interactions. [9][10][11][12] But reversible reactions can also be used in each generation. In 2005, Hirsch and co-workers [13] presented a supramolecular dendrimer in which the core, branching units, and outer-most units (caps) self-assemble through hydrogen bonds.…”

Metal‐Induced Chiral Folding of Depsipeptide Dendrimers

“…Incorporation of metal ions into dendritic structures per se has been investigated previously in a variety of cases. [45][46][47][48] Dendrimers containing metal complexes in the core, in the branches, and at the periphery, as well as dendritic systems using metals as branching centers, have been synthesized. [48] However, there have only been a few reports on metal-complexation-induced conformational changes in dendritic ligands.…”