Theoretical insight on model linear oligomers and their ring-fused analogs used in organic electronics

Theoretical systematic study compares chemical and electronic structure of six series of linear aromatic oligo-mers and their ring-fused analogs with various chain length of 5-and 6-membered rings. Chemical structure was described by structural HOMED and one-electron density topology EL aromaticity descriptors. The calculations demonstrated that the diradical electronic ground-state system is energetically preferred for larger six-membered acenes where the electronic structure can be separated into two linear polyene chains. The influence of inter-molecular interaction on the aromaticity perturbation in crystals was also analyzed for 20 available X-ray structures. The aromaticity of central ring is lowered for longer molecules in solids. Next, the primary effect of aromatic chain elongation on frontier orbital energies and vertical excitation energies was predicted. The calculated data were correlated with experimental ones and polymer limits on investigated properties were estimated.

Automated summary

This study compares the chemical and electronic structure of various series of linear aromatic oligomers and their ring-fused analogs. The effects of chain length and inter-molecular interactions on aromaticity and electronic properties were investigated. The results were correlated with experimental data and used to estimate the limits of polymer properties.