Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

• Published in: Journal of luminescence Vol. 161; pp. 382 - 388
• Main Authors: Małecki, Jan G., Łakomska, Iwona, Maroń, Anna, Szala, Marcin, Fandzloch, Marzena, Nycz, Jacek E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2015
• Subjects: 8-Hydroxyquinoline-derived ligands; Copper(I) complexes; Luminescence; Copper(I) complexes; 8-Hydroxyquinoline-derived ligands; Luminescence
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2015.01.041

The pseudotetrahedral complexes of [Cu(PPh3)2(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88ms (frozen DCM solution up to 6.7ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. •Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands.•Very long lived phosphorescent copper(I) complexes.•[Cu(PPh3)2(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9ms).•In frozen MeOH:EtOH solution lifetime increases to 7ms.•Quantum efficiency equal to 4.7%.