title: Palladium-catalyzed direct arylation of luminescent bis-cyclometalated iridium(III) complexes incorporating C^N- or O^O-coordinating thiophene-based ligands: an efficient method for color tuning.
abstract: We report the palladium-catalyzed direct 5-arylation of both metalated and nonmetalated thiophene moieties of iridium complexes 2, 3, and 4 with aryl halides via C-H bond functionalization. This method opens new routes to varieties of Ir complexes in only one step, allowing easy modification of the nature of the ligand. The photophysical properties of the new functionalized complexes have been studied by means of absorption and emission spectroscopy. The extension of the π-conjugated system induces a bathochromic and hyperchromic shift of the absorption spectra, an effect reproduced by first principle calculations. Indeed, the bathochromic shifts are related to a more delocalized nature of the excited-states. All complexes are photoluminescent in the red region of the spectrum. This study establishes that arylation of the thienyl ring affects strongly the electronic properties of the resulting complexes, even when the thienyl ring is remote and not directly metalated to the iridium center, as in the thienyltrifluoroacetonate complex 4.
authors.affiliation: UMR-CNRS 6226, Institut des Sciences Chimiques de Rennes, Université de Rennes 1 , Campus de Beaulieu, 35042 Rennes, France.
authors.forename: Kassem
authors.initials: K
authors.lastname: Beydoun
authors.forename: Moussa
authors.initials: M
authors.lastname: Zaarour
authors.forename: J A Gareth
authors.initials: JA
authors.lastname: Williams
authors.forename: Thierry
authors.initials: T
authors.lastname: Roisnel
authors.forename: Vincent
authors.initials: V
authors.lastname: Dorcet
authors.forename: Aurélien
authors.initials: A
authors.lastname: Planchat
authors.forename: Abdou
authors.initials: A
authors.lastname: Boucekkine
authors.forename: Denis
authors.initials: D
authors.lastname: Jacquemin
authors.forename: Henri
authors.initials: H
authors.lastname: Doucet
authors.forename: Véronique
authors.initials: V
authors.lastname: Guerchais