Self-assembly of truxene derivatives investigated by STM

Truxene and its derivatives were synthesized, and their assembly structures were studied by scanning tunneling microscopy (STM) technique. Parallelogram-shaped dimers with different contrast can be resolved for two-dimensional assembly of truxene molecules. Moreover, the side-chain-effect is introduced into the system to tune and control the assembling structures of the truxene for one of the two truxene derivatives, hexatetradecyltruxene (truxene-C₁₄) with six C₁₄ side chains, showing stripe assembling structures with different contrast. While for the other one, 2,7,12-tertriazine-5,5,10,10,15,15-hexatetradecyltruxene (tertriazine-truxene- C₁₄) form the intermolecular multi-hydrogen bonds. Hydrogen bond interaction influences the molecular orientation and conformation of these two-dimensional supramolecular architectures. These results demonstrate the role of hydrogen bonds in molecular assembly formations and what is more, would be beneficial for understanding and fine tuning of the assembling of truxene-related opto-electronic materials.