Designing molecules with tailored photochemical properties could be possible thanks to computational chemists in Germany.
Pi-conjugated compounds have alternating single and multiple bonds in their structure. Their electrons are delocalised over the system and the optical and electronic properties of the materials are influenced by the strength of this conjugation.These materials can find use in organic light emitting diodes and molecular switches that are activated photochemically.
Gernot Frenking and Israel Fernández at the Philipps University of Marburg found that the strength of pi-conjugation can be estimated using computational chemistry.
Benzene is a simple example of pi-conjugation
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Using a method known as energy decomposition analysis (EDA) Frenking and Fernández studied a group of pi-conjugated compounds called cyanoethynylethenes. The researchers calculated the energy associated with the stabilisation of the molecules by the conjugation. There was a strong correlation between these energies and 13C NMR signals from the compounds which indicate the strength of conjugation.
EDA could be used to quantitatively analyse conjugation, said Frenking. ‘It would then be possible to make predictions about the strength of pi-conjugation. Considering the enormously important field of pi conjugating molecules, this would make a large impact on progress,’ he added.
Rachel Warfield
