A Theoretical Investigation into the Homo- and Hetero-leptic Cu(I) Phosphorescent Complexes Bearing 2,9-dimethyl-1,10-phenanthroline and bis [2-(diphenylphosphino)phenyl]ether Ligand

Cu(I) complexes have received widespread attention as a promising alternative to traditional noble-metal complexes. Herein, we systematically study the properties of Cu(I) complexes from homo- to hetero-ligands, and found the following: (1) hetero-ligands are beneficial to regulate phosphorescent efficiency; (2) when the hetero-ligands in a tetracoordinated Cu(I) complex are 1:1, the ligands coordinate along the d(x2-y2) direction of Cu(I) ion, which can observably suppress structural deformation; (3) unlike the P<^>P ligand, the N<^>N ligand can enhance the participation of Cu(I) during the transition process; (4) the addition of an appropriate amount of P<^>P ligand can effectively raise the energy level of HOMO (highest occupied molecular orbital), enhance the proportion of LLCT (ligand-ligand charge transfer), and thereby increase the available singlet emission transition moments which can be borrowed, thus promoting the radiative decay process. As a result, this work provides a detailed understanding of the effects of different ligands in Cu(I) complexes, and provides a valuable reference and theoretical basis for regulating and designing the phosphorescent properties of Cu(I) complexes in the future.

Automated summary

This study systematically investigates the properties of Cu(I) complexes with different ligands, and finds that hetero-ligands are beneficial for regulating phosphorescent efficiency. The 1:1 coordination of hetero-ligands in a tetracoordinated Cu(I) complex suppresses structural deformation, while the N<^>N ligand enhances Cu(I) participation. The addition of an appropriate amount of P<^>P ligand increases the energy level of HOMO and the proportion of LLCT, promoting the radiative decay process.