A first-generation “cyanostar” dendrimer and its The olefin metathesis reaction applications in the pharmaceutical industry image. The first dendrimers were made by divergent synthesis approaches by Fritz Vögtle in 1978, R. Dendritic molecules are characterized by structural perfection.
Dendrimers and dendrons are monodisperse and usually highly symmetric, spherical compounds. The properties of dendrimers are dominated by the functional groups on the molecular surface, however, there are examples of dendrimers with internal functionality. Dendrimers are also classified by generation, which refers to the number of repeated branching cycles that are performed during its synthesis. Each successive generation results in a dendrimer roughly twice the molecular weight of the previous generation. One of the very first dendrimers, the Newkome dendrimer, was synthesized in 1985. This macromolecule is also commonly known by the name arborol. PAMAM, is perhaps the most well known dendrimer.
Dendrimers can be considered to have three major portions: a core, an inner shell, and an outer shell. Ideally, a dendrimer can be synthesized to have different functionality in each of these portions to control properties such as solubility, thermal stability, and attachment of compounds for particular applications. Synthetic processes can also precisely control the size and number of branches on the dendrimer. The dendrimer is assembled from a multifunctional core, which is extended outward by a series of reactions, commonly a Michael reaction. Dendrimers are built from small molecules that end up at the surface of the sphere, and reactions proceed inward building inward and are eventually attached to a core. This method makes it much easier to remove impurities and shorter branches along the way, so that the final dendrimer is more monodisperse. There are ample avenues that can be opened by exploring this chemistry in dendrimer synthesis.