EU COST CHEMISTRY D26 :- European collaboration for calculation-inspired synthesis of NLO-responsive aryl and helicenyl organometallics

This proposal seeks funding to enhance an existing collaboration to allow the research objectives to be addressed within the time-frame of the EU COST D26 programme on computational chemistry. Because the UK is a signature member of the EU COST programme, EPSRC allows the opportunity to consider small grants to assist UK members of Working Groups of COST Actions. This research is in this category (D26WG0013/02: http://costchemistry.epfl.ch/docs/D26/d26-13-02.htm), and the work will achieve a transfer of expertise form specialist Density Functional Theory (DFT) groups in Fribourg and Paris to assist the Norwich-based research group of the PI (Stephenson), and will also allow exchange of materials with helicene specialists in Milan. Final products will be sent to Leuven for photophysics evaluation. The research will compare theoretical and experimental results, gained entirely in collaboration with other European research groups specialising in DFT and helicene synthesis. Molecules with helical pi systems contain electrons distributed within a helical environment which interact with light in an unusual way, which will be investigated by a combination of synthesis and calculation-based studies. Normally when polarising groups (electron accepting and electron donating groups) are attached to pi systems, irradiation with laser light promotes second harmonic generation (SHG: emission of light at twice the frequency of the illuminating light) but this has a strict requirement for a non-centrosymmetric arrangement of molecules. When both the electric and magnetic dipoles of the laser light are taken into account, however, this requirement no longer holds, and SHG can occur with centrosymmetric bulk samples. The molecules needed to study this phenomenon must have high molecular anisotropies and well as the normal polarised pi systems. The examples to be studied in this research are helicene derivatives substituted at one end with a cationic organometallic structure that serves as the polarising group.