Phosphorescent Cyclometalated Iridium(III) Complexes Bearing Ethynyl‐Extended 2‐(2'‐Hydroxyphenyl) Benzoxazole Ancillary Ligands. Issue 18 (29th April 2020)

• Record Type: Journal Article
• Authors: Massue, Julien; Ulrich, Gilles; Monti, Filippo; Barbieri, Andrea
• Is Part Of: European journal of inorganic chemistry. Issue 18(2020)
• Page Start: 1775
• Page End: 1782
• Publication Date: 2020-04-29
• Subjects: Iridium -- Hydroxybenzazoles -- Luminescence -- Photophysics -- Charge transfer; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202000114
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : This article describes the synthesis and full photophysical studies at room and low temperature of a series of iridium(III) complexes incorporating an ethynyl‐extended benzoxazole‐based ancillary ligand. The electronic nature of the terminal end‐group of the ancillary ligand was modulated by the simple introduction of electron‐donating (Me, NBu2 ) or ‐withdrawing (CN) groups. For all complexes, TD‐DFT calculations showed that the lowest‐lying transition was ligand‐centered and that the nature of the first triplet state was very sensitive to electronic parameters leading to a charge transfer (CT) or locally excited (LE) excited state, always centered on the ancillary ligand. Singlet oxygen sensitization studies were performed on all compounds, showing that iridium(III) complexes containing cyano‐functionalized ligands feature sensitization parameters, making them attractive candidates for photodynamic therapy. Abstract : The photophysical features of iridium(III) complexes incorporating an ethynyl‐extended benzoxazole‐based ancillary ligand are effectively modulated by the simple introduction of electron‐donating (Me, NBu2 ) or ‐withdrawing (CN) moieties on the terminal end‐group, leading to CT or LC excited‐states. The complexes containing the cyano‐functionalized ligands features singlet oxygen sensitization parameters, making them attractive candidates for PDT.