LUMINESCENT M-CYCLES · Diethynylmetallacyclopentadienes - Investigations of a new class of luminescent organometallics

The investigation of diethynylmetallacyclopentadienes is of fundamental interest due to their photophysical properties and potential use as organometallic luminophores for organic light emitting diodes (OLEDs) and in 2-photon excited fluorescence/phosphorescence imaging as well as other 3rd order non-linear optical (NLO) applications. Therefore, access to a library of new diethynylmetallacyclopentadienes will be developed and their luminescent behaviour will be examined. As Ir(ppy) complexes have shown the most promise for OLED applications, other metal centres such as Ir and Pt will be employed for the metallacycle formation in order to access triplet luminescence. Furthermore, synthesis of new symmetric and unsymmetric 1,3-butadiynes will be carried out in order to examine the influence of donor/acceptor substitution of the metallacyclopentadienes, which should lead to immense progress concerning the fine-tuning of the luminescence. The influence of strongly donating ligands attached to the metal will aid in understanding the role of the metal centre and will raise the energy of the metal orbitals which is expected to increase the M-L charge transfer component of the optical transition. Theoretical studies and flash-photolysis will be used to obtain information regarding the geometries and electronic structures of the ground and excited states to complete the picture. It is important to gain an understanding of the photophysical properties of the metallacyles through detailed experimental studies in combination with theoretical studies, from which structure-property relationships will be obtained, enabling the design of new metallacycles with specific optical properties.