Dispersion driven isomerism in sigma-bonded acene dimers

• Applicant: Professor Dr. Holger Bettinger
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 271106968

Dispersion interactions between aromatic pi systems are well known to be responsible for the poor solubility of large polycyclic aromatic hydrocarbons. These forces also hold the graphene sheets together in graphite. In covalently bound dimers of acenes, substructures of graphene, dispersion interactions between extended pi systems were predicted by computational means to be responsible for conformational isomerism between open and closed forms. The stiffness of the sigma system prevents formation of the closed forms of currently known acene dimers. The project aims at synthesis and computational study of acene dimers with well-defined lengths of the acene wings. The elongation starting from anthracene dimers allows adjusting the length of the acene wings and study the possible dispersion driven isomerism. Large bulky alkyl groups that may act as dispersion energy donors and solubilizing groups allow investigation of their possible influence on the photodimerization of anthracenes and on the dispersion driven isomerism of acene dimers.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1807: Control of London Dispersion Interactions in Molecular Chemistry