Dendritic, or highly branched, structures exist in nature in various dimensions in both biological and non-biological systems. These structures provide maximized surface areas; therefore, they provide a platform to optimize energy, nutrition, and information exchange. In the (macro)molecular regime, the size, shape, and functionality are important features of a dendrimer that can be precisely controlled,1,2 which ultimately affect their physical properties, such as solution conformation. A unique characteristic of dendritic architectures is their globular or "3-dimensional" shape that can be amplified by the use of shape-persistent building blocks.3 Thus, adamantane was chosen, as a building block, for the construction of 1 to 3 branched, dendritic frameworks. Adamantane is an ideal candidate due to its three, fused cyclohexane rings, which are all in strain-free, chair conformations that can generate a 3-D shape-persistent structure.4 The construction of adamantane building blocks and their incorporation into dendritic macromolecules will be discussed.
Adamantane functionalization was achieved at the bridgehead positions to generate the novel 1-amino-3,5,7-tris(methoxycarbonyl)adamantane monomer, which with the corresponding 1,3,5,7-adamantanetetracarboxylic acid will be used to construct the initial dendrimers. These materials will be compared to the well-known Newkome-type dendrimers that have been constructed with di-tert-butyl-4-amino-4-[2-(tert-butoxycarbonyl) ethyl] heptanedioate (Behera's amine).2 Notably, this building block has a similar shape yet does not possess shape-persistence.