Luminescent molecular materials based on nitrogen heterocyclic organometallic complexes

Cyclometalated platinum(II) complexes bearing diazine-based bidentate or tridentate ligands are an attractive class of luminescent materials for use as a dopant in the emission layer of PhOLEDs. Due to the strong spin-orbit coupling of Pt(II), complexes are able to efficiently harvest both singlet and triplet electro-generated excitons, thus opening the possibility to achieve theoretically 100% internal quantum efficiency in such devices. Structure of the four-coordinated Pt(II) complexes can accommodate bidentate, tridentate, or tetradentate chelating ligands, with ancillary ligands where necessary which allows considerable flexibility in engineering complexes with desired photophysical and electrochemical properties. In this thesis, we are interested in the design of three new series of phosphorescent cyclometalated platinum (II) complexes, containing tridentate (C^N^N and N^C^N) and bidentate (C^N) coordinating ligands based on pyrimidine and other diazines. In addition to their synthesis and characterization, photophysical and electrochemical properties of these complexes were experimentally studied and explained with the help of theoretical calculations. The results demonstrate that the appropriate functionalization of the cyclometalating ligand and the choice of the auxiliary ligand allow to modulate the photophysical and electrochemical properties of these complexes. The influence of various structural modifications on emission properties has been thoroughly studied and structure properties relationships were highlighted.