Synthesis, Structure, and Photophysical Properties of Yellow-Green and Blue Photoluminescent Dinuclear and Octanuclear Copper(I) Iodide Complexes with a Disilanylene-Bridged Bispyridine Ligand

The synthesis, structural, and photophysical investigations of CuI complexes with a disilanylene-bridged bispyridine ligand 1 are herein presented. Dinuclear (2) and ladder-like (3) octanuclear copper(I) complexes were straightforwardly prepared by exactly controlling the ratio of CuI/ligand 1. Single-crystal X-ray analysis confirmed that dinuclear complex 2 had no apparent pi horizontal ellipsis pi stacking whereas octanuclear complex 3 had pi horizontal ellipsis pi stacking in the crystal packing. In the solid state, the complexes display yellow-green (lambda(em) = 519 nm, phi = 0.60, tau = 11 mu s, 2) and blue (lambda(em) = 478 nm, phi = 0.04, tau = 2.6 mu s, 3) phosphorescence, respectively. The density functional theory calculations validate the differences in their optical properties. The difference in the luminescence efficiency between 2 and 3 is attributed to the presence of pi horizontal ellipsis pi stacking and the different luminescence processes.

Automated summary

This study presents the synthesis, structure, and photophysical properties of CuI complexes with a disilanylene-bridged bispyridine ligand 1. By controlling the CuI/ligand 1 ratio, dinuclear and octanuclear copper(I) complexes were prepared, exhibiting different pi stacking in crystal packing and different phosphorescence colors and efficiencies in the solid state. The differences in luminescence efficiency between the two complexes are attributed to the presence of pi stacking and different luminescence processes.