Novel functional tripodal monomolecular films

• Applicant: Professor Dr. Michael Zharnikov
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 437355715

The major goal of the proposal is establishing and optimizing a new type of tripodal monomolecular films - functional self-assembled monolayers (SAMs), based on the triptycene unit - in context of fundamental issues of monomolecular self-assembly and in view of potential applications. The architecture of this system is distinctly different from the tetrahedral geometry of conventional tripodal moieties. The advantages of this system are the self-assembly ability of triptycene, efficient electronic coupling within the triptycene framework, flexibility in term of molecular design including the character and number of the tail groups, the density of thereof upon the monomolecular assembly, and upright orientation of these moieties. The triptycene scaffold will be decorated with suitable anchor groups, such as thiols or carboxyls, allowing efficient bonding and self-assembly on gold and silver substrates in tripodal adsorption configuration, with individual phenyl rings oriented perpendicular to the substrate. This basic molecular architecture will be optimized (e.g. by the introduction of the linkers) and used for further functionalization, with either one or three functional tail groups attached in either bridgehead or tripodal configuration, respectively. The first configuration allows a comparably large separation of the functional tail groups such as active sites for the click reaction, receptors for specific attachment of biomolecules (proteins, etc), molecular switches, and coordination sites for metal ions, with the advantages of strongly suppressed sterical effects and flexible supramolecular design starting from the fabricated template. The second configuration allows a high density of the functional tail groups directed perpendicular to the substrate, which can be in particular useful for interface dipole engineering, as far as dipolar tail groups are used. Different functional groups will be tried to prove the possibilities, flexibility, and reliability of the approach as well as to design model systems for potential applications. Among other issues, the triptycene-based films will be characterised and optimized in context of interface dipole engineering, efficiency of the click reaction, as well as intra- and intermolecular charge transfer. The work will be performed in collaboration with several partner groups, performing the necessary synthetic work, complementary characterization experiments, and modelling of the structure and properties of the fabricated monomolecular films with state-of-the-art computational tools.

• DFG Programme: Research Grants
• International Connection: Austria, Japan, United Kingdom
• Cooperation Partners: Professor Dr. Manfred Buck; Professor Dr. Takafumi Fukushima; Professor Dr. Egbert Zojer