Supramolecular dendrimer chemistry: Molecular recognition within the dendritic environment

This paper describes the use of a dendritic shell to modify molecular recognition properties at a well-defined binding site deep within the branched architecture. Receptors based on different interactions are discussed. Dendritic Fe(II) porphyrins coordinatively bind dioxygen, and the branched architecture modulates both the strength and selectivity of binding. Dendritic cyclophanes (dendrophanes) hydrophobically snare aryl or steroid guests. The branching changes the micropolarity of the recognition unit at the core. Such dendrophanes have also been used to assemble high mass supramolecular structures, the stability and stoichiometry of which are controlled by the dendritic diameter. Dendrimers for specific applications in molecular recognition can require new, carefully designed branches, and the synthesis of such a branch is described. These new branches are then used to prepare chiral dendritic receptors based on a functionalised 9,9'-spirobi[9H-fluorene] core which bind glucosides via hydrogen bonding. The enantio- and diastereo-selectivities of these optically pure, dendritic clefts (dendroclefts) are altered by the presence of the dendritic branching.