Molecular rods and stars through cross-coupling reactions

In the quest of smart electronic devices the society faces the challenge of miniaturization. Chemists, who know how to manipulate the smallest but still diverse bricks of the matter, namely the molecules, have the adequate tools for this challenge. A better understanding of the rules applying in the nanoworld is essential to build any functional molecular device construction. In this work three different approaches to answer these questions were followed.
The first one is the synthesis of a molecule suited to integrate a junction of two nanotube electrodes. When a voltage is applied the molecular bridge emits a characteristic light. The originality of this approach lies in the particularity of having an electroluminescence produced by a single molecule. Several molecular rods suiting this set-up were synthesized.
The second approach deals with surface functionalization. A surface network with hexagonal cavities is filled with three-arm star shaped molecules with different sizes and functionalities. The structures of these targets had to be adapted to solve size matters as well as their behavior in the cavities. The dimensions of the stars were successively reduced in order to match the pore size and in a second step decorated with hydroxy groups to slow down or ideally stop their rotation in the hexagonal pores.
To explore the potential and the limitation of molecules as electronic devices, a two terminal electronic component was targeted. The third approach describes indeed the synthesis of a molecule that acts as a single molecular diode meant to have the same properties as the macroscopic one, namely it lets circulate the current in only one direction.
These rectification properties were studied by bridging two gold electrodes with the molecular diodes. These three projects geared towards the design of physical properties on a single molecule level, demonstrate the scientific challenges as well as the potential of tailor-made molecular building blocks in future molecular devices.