Influence of the distance between oxygen donor atoms and copper(I) ion on the efficiency of intramolecular exciplex quenching in homoleptic copper(I) complexes

Abstract

Exciplex quenching is one of the most deleterious phenomena which efficiently leads to the extinction of the excited properties of copper(I) complexes. This process consists in the ligation of an extra ligand on the copper ion when the complex is in the excited state. This extra ligand can be a solvent molecule, and more rarely a donor atom located on the molecular structure of the complexes themselves. In this article, we report the synthesis of three homoleptic copper(I) complexes where the copper (I) ion is coordinated by 1,10-phenanthroline derivatives, bearing floppy side chains in positions 2 and 9 and containing oxygen atoms. The latter can act as extra ligands for the copper ion. We study the impact of these oxygen atoms on the physical and chemical properties of the associated copper (I) complexes. We highlight the fact that the distance between the oxygen atoms and the copper ion is determinant for the existence of exploitable excited state properties.