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Intramolecular π Stacking in Cationic Iridium(III) Complexes with Phenyl‐Functionalized Cyclometalated Ligands: Synthesis, Structure, Photophysical Properties, and Theoretical Studies
- Source :
- European journal of inorganic chemistry, 2014, Vol.2014(14), pp.2376-2382 [Peer Reviewed Journal]
- Publication Year :
- 2014
- Publisher :
- Wiley, 2014.
-
Abstract
- The syntheses of two new heteroleptic cationic iridium complexes containing 2,6-diphenylpyridine (Hdppy) and 2,4,6-triphenylpyridine (Htppy) as the cyclometalated ligands, namely, [Ir(dppy)2phen]PF6 (1, phen = 1,10-phenanthroline) and [Ir(tppy)2phen]PF6 (2), are described. The X-ray crystal structure of 2 reveals a distorted octahedral geometry around the Ir center and close intramolecular face-to-face π–π stacking interactions between the pendant phenyl rings at the 2-position of the cyclometalated ligands and the NN ancillary ligand. This represents a new π–π stacking mode in charged Ir complexes. Complexes 1 and 2 are green photoemitters: their photophysical and electrochemical properties are interpreted with the assistance of density functional theory (DFT) calculations. These calculations also establish that the observed intramolecular interactions cannot effectively prevent the lengthening of the Ir–N bonds of the complexes in their metal-centered (3MC) states. Complexes 1 and 2 do not emit light in light-emitting electrochemical cells (LECs) under conditions in which the model compound [Ir(ppy)2phen]PF6 (3) emits strongly. This is explained by degradation reactions of the 3MC state of 1 and 2 under the applied bias during LEC operation facilitated by the enhanced distortions in the geometry of the complexes. These observations have important implications for the future design of complexes for LEC applications.
- Subjects :
- Luminescence
Chemistry
Ligand
Stacking
Cationic polymerization
Light-emitting cells
chemistry.chemical_element
Crystal structure
Iridium
Photochemistry
Inorganic Chemistry
Density functional calculations
Crystallography
Photophysics
Intramolecular force
Octahedral molecular geometry
Density functional theory
Subjects
Details
- ISSN :
- 10990682 and 14341948
- Volume :
- 2014
- Database :
- OpenAIRE
- Journal :
- European Journal of Inorganic Chemistry
- Accession number :
- edsair.doi.dedup.....22f30a5ded7b24055ccb1c5da0c33fb1