Colored phosphorescent platinum complexes

The development of transition metal complexes with phosphorescence emission properties is a crucial research axis, in particular for applications as second generation organic light-emitting diodes (OLEDs) for lights and display. On the strength of their experiments in synthesis and the study of simple structural variations, scientists from the Rennes  Institute of chemical sciences (ISCR) were able to access a chemical library of cyclometallated platinum(II) complexes based on phenyldiazine ligands. Structure/photophysical properties relationships, with the help of theoretial calculation performed by Jean-Yves Saillard and Samia Kahlal from ISCR, have been highlighted, allowing acess to the emission of phosphorescence ranging from green to infrared.

The strategy consisted, starting from a very simple cyclometallated platinum(II) complex containing a bidentate ligand 2-phenylpyrimidine and two auxiliary ligands chloride and pyridine, in several structural modifications leading to a chemical library of 24 complexes.

In order to illustrate the effect on the luminescence properties, the researchers showed that the addition of an electron-donating group in a para position with respect to the metal center allows a shift towards the red of the emission and an increase in the quantum efficiency of photoluminescence.

Other structural modifications on the pyrimidine ring as well as the change of the heterocycle induced modifications of the emission from blue to red with a notable increase in the quantum yields of photoluminescence in solution and in the solid state. Complexes emitting in the near infrared have thus been obtained with photoluminescence quantum yields in the solid state > 0.06, particularly attractive in this range of the spectrum in the context of application in OLEDs for new perspectives of use such as the night vision, biosensors or photochemistry. Work is currently underway to incorporate these molecular materials into OLED devices.

The development of NIR (Near InfraRed) OLEDs presents a real challenge.

This work was a part of the PhD thesis of Mariia Hruzd.

References

• Phosphorescent cyclometallated platinum(II) complexes with phenyldiazine N^C ligands
  Mariia Hruzd, Samia Kahlal, Nicolas Le Poul, Laurianne Wojcik, Marie Cordier, Jean-Yves Saillard, Julián Rodríguez-López, Françoise Robin-le Guen, Sébastien Gauthier, Sylvain Achelle
  Dalton Transactions, 2023 sous presse
  https://doi.org/10.1039/d2dt03690h
   
• Cyclometallated 2-phenylpyrimidine derived platinum complexes : synthesis and photophysical properties
  Michaela Fecková, Samia Kahlal, Thierry Roisnel, Jean-Yves Saillard, Julien Boixel, Mariia Hruzd, Pascal le Poul, Sébastien Gauthier, Françoise Robin-le Guen, Filip Bureš, Sylvain Achelle
  Eur. J. Inorg. Chem., 2021, 16, 1592-1600
  https://doi.org/10.1002/ejic.202100155

Contacts

• Sylvain Achelle, Univ Rennes, ISCR-CNRS UMR 6226, F-35000 Rennes, France
  sylvain [dot] achelleuniv-rennes [dot] fr
   
• Sébastien Gauthier, Univ Rennes, ISCR-CNRS UMR 6226, F-35000 Rennes, France
  sebastien [dot] gauthieruniv-rennes [dot] fr
   
• Françoise Robin-Le Guen, Univ Rennes, ISCR-CNRS UMR 6226, F-35000 Rennes, France
  francoise [dot] le-guenuniv-rennes [dot] fr

Published March 10, 2023