Dendrimers [1] are repetitively branched molecules.[2][3] The name comes from the Greek word δένδρον (dendron), which translates to "tree". Synonymous terms for dendrimer include arborols and cascade molecules. However, dendrimer is currently the internationally accepted term. A dendrimer is typically symmetric around the core, and often adopts a spherical three-dimensional morphology. The word dendron is also encountered frequently. A dendron usually contains a single chemically addressable group called the focal point. The difference between dendrons and dendrimers is illustrated in figure one, but the terms are typically encountered interchangeably.[4]
Figure 2: Crystal structure of a first-generation polyphenylene dendrimer reported by Müllen et al.[5]
The first dendrimers were made by divergent synthesis approaches by Fritz Vögtle in 1978,[6] R.G. Denkewalter at Allied Corporation in 1981,[7][8] Donald Tomalia at Dow Chemical in 1983[9] and in 1985,[10][11] and by George Newkome in 1985.[12] In 1990 a convergent synthetic approach was introduced by Jean Fréchet.[13] Dendrimer popularity then greatly increased, resulting in more than 5,000 scientific papers and patents by the year 2005.