Bright Long‐Lived Circularly Polarized Luminescence in Chiral Chromium(III) Complexes. Issue 18 (11th March 2021)

• Record Type: Journal Article
• Authors: Jiménez, Juan‐Ramón; Poncet, Maxime; Míguez‐Lago, Sandra; Grass, Stéphane; Lacour, Jérôme; Besnard, Céline; Cuerva, Juan M.; Campaña, Araceli G.; Piguet, Claude
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 18(2021)
• Page Start: 10095
• Page End: 10102
• Publication Date: 2021-03-11
• Subjects: brightness -- chirality -- chromium -- CPL -- dissymmetry factor; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202101158
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A series of highly emissive inert and chiral Cr III complexes displaying dual circularly polarized luminescence (CPL) within the NIR region have been prepared and characterized. The helical [Cr(dqpR)2 ] 3+ (dqp=2, 6‐di(quinolin‐8‐yl)pyridine; R=OCH3, Br or C≡CH) complexes were synthesized as racemic mixtures and resolved into their respective PP and MM enantiomers by chiral stationary phase HPLC. The corresponding enantiomers show large g lum ≈0.2 and high quantum yield of up to 17 %, which afford important CPL brightness of up to 170 m −1 cm −1, a key point for applications as chiral luminescent probes. Moreover, the long‐lived CP‐NIR emission provided by these chromophores (ms range) in aqueous solution opens the way toward the quantification of chiral targets in biological systems with time‐gated detection. Thus, such chiral chromophores based on earth abundant and inert 3d metals open new perspectives in the field of CPL and represent an alternative to precious 4d, 5d and to labile 4f metal‐based complexes. Abstract : A family of chiral Cr III chromophores with dual circularly polarized emission within the NIR has been synthesized and characterized. The rational design of the ligand skeleton on chiral Cr III complexes improves the chiral resolution as well as the CPL brightness. These optimized chiral chromophores based on earth‐abundant metals are promising candidates for the emerging chiral technologies.