4,4'-Bisaryl-BBI has the potential to be a building block for a variety of more complex ligands (Figure 1). Taking a schematic approach, 4,4'-bisaryl-BBI can adopt a U-shaped conformation which has two differentiated binding sites, namely, the exo binding sites [N(1) and N(1')] and the endo binding sites [N(3) and N(3')]. 26 The schematic lines made by two aromatic moieties are parallel, and the distance between these should be ca. 8 Å. 27 This cleftlike structure ...
