F. Alary, M. Boggio-Pasqua, J.-L. Heully, R. Piau ; collaboration : A. Igau, E. Lebon, P. Sutra (LCC, Toulouse)
Alain Igau’s group (LCC Toulouse) synthesizes ruthenium complexes containing phosphorus ligands [Ru(tpy)(bpy)PR2H, R=iPr, phenyl]2+ to test them as dyes for Dye-Sensitized Solar Cells (DSSC). Most of these complexes are non luminescent at room temperature. Their photophysical properties (absorption, emission, excited state lifetime, nonradiative processes) had never been studied theoretically before.
We have been able to rationalize the non luminesence of these complexes and to describe the nature of the Ru-P interaction in about ten different complexes. A low lying 3MC state is often responsible for luminescence quenching, but in some cases the topology of the ground and excited potential energy surfaces is to blame. We have described the Ru-P bond using Natural Bond Orbital (NBO) analysis, which evidenced different degrees of backdonation.
The long term objective of this project is to rationalize the electronic effects of the ligands (π system to control the 3MLCT state, σ system for the 3MC state) and be able to offer predictive tools based on a better understanding of the lelectronic effects at stake for our collaborators.
This project has led to 3 publications :
Chem. Comm. 2012, 48, 741 link
J. Phys. Chem. A 2013, 117, 12821 link
Inorg. Chem. 2014, 53, 1946 link