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Iridium(III) Bis-tridentate Complexes with 6-(5-Trifluoromethylpyrazol-3-yl)-2,2â²-bipyridine Chelating Ligands: Synthesis, Characterization, and Photophysical Properties.
- Source :
-
Organometallics . Jul2010, Vol. 29 Issue 13, p2882-2891. 10p. - Publication Year :
- 2010
-
Abstract
- A novel family of iridium(III) bis-tridentate complexes are reported that contain the deprotonated, Nâ§Nâ§N-coordinated 6-(5-trifluoromethylpyrazol-3-yl)-2,2â²-bipyridine (fpbpyH) ligand. The monocationic homoleptic iridium(III) complex [Ir(fpbpy)2](PF6) (1) was first prepared by treatment of IrCl3·3H2O with 2.2 equiv of fpbpyH in degassed ethylene glycol at 196 °C and structurally characterized by single-crystal X-ray crystallography. The reaction of Ir(tpy)Cl3with an equimolar amount of fpbpyH under comparable conditions generated a dicationic heteroleptic iridium(III) complex, [Ir(fpbpy)(tpy)](PF6)2(2), featuring one 2,2â²:6â²2â²â²-terpyridine (tpy) in place of one fpbpy. The charge-neutral heteroleptic complex [Ir(fpbpy)(dppy)] (3) (dppyH2= 2,6-diphenylpyridine) was also afforded successfully via a solvent-free method, giving a complex with one dppy bound to the Ir(III) ion through two carbon atoms for the cyclometalation reaction. Complexes 1â3are emissive in acetonitrile solution at ambient temperature, perhaps best assigned to the MLCT character, mixed with intraligand charge transfer (ILCT) transition inside fpbpy and ligand-to-ligand charge transfer (LLCT) Ï(fpbpy) â Ï*(tpy) or Ï(dppy) â Ï*(fpbpy) transition, respectively, which are supported by DFT calculations. It is noteworthy that the photoluminescence of 3displays a significant red-shifting compared to those of 1and 2due to the large reduction of the HOMOâLUMO energy gap as a consequence of the introduction of the more electron-donating and strong ligand-field cyclometalate dppy chelate. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02767333
- Volume :
- 29
- Issue :
- 13
- Database :
- Academic Search Index
- Journal :
- Organometallics
- Publication Type :
- Academic Journal
- Accession number :
- 51995274
- Full Text :
- https://doi.org/10.1021/om100186k