Synthesis and Covalent Grafting of Tripod‐Shaped Oligo(p‐phenylene)s End‐Capped with Azide Groups

Here we report the synthesis and characterization of several tripod-shaped oligo(p-phenylene)s molecules with legs composed of five and three phenylene units, compounds 1 and 2, respectively. In these structures, each leg is end-capped with an azide group and the terminal functional arm contains an acetylene or bromine group. The presented synthesis has as the key step a Pd-catalyzed Suzuki cross-coupling reaction. In particular, the iodine derivative from the silicon core molecule reacts with the appropriate oligo(p-phenylene) boron derivative, thus generating the final tripod-shaped structure. The azide end-capped leg is specifically designed for its covalent incorporation on alkynyl terminated silicon surfaces in an easy and reproducible way. As a preliminary study, we present the nanostructuration of tripod 2a on alkynyl-functionalized silicon wafers through copper-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction.