Dinuclear Pt(II) Complexes with Red and NIR Emission Governed by Ligand Control of the Intramolecular Pt-Pt Distance

Red and near-infrared (NIR) phosphorescent double-decker dinuclear Pt(II) complexes were synthesized, and theirstructural and spectroscopic properties were characterized. The Pt(II) complexes, which are composed of achiral ligands and arethemselves chiral, were shown to exist as racemic mixtures using single-crystal X-ray crystallography. The Pt(II) complexes havedifferent intramolecular Pt-Pt distances that are governed by the electronic characteristics of the component C<^>N ligands.Specifically, strengthening of pi-back-donation between Pt(II) and N atom of the C<^>N ligand leads to shortening of the Pt-Ptdistance. The results of both experimental and computational investigations show that the Pt-Pt distances in the dinuclear Pt(II)complexes significantly influence the band gap energies and corresponding emission wavelengths. Consequently, the uncovered C<^>Nligand based method tofinely control intramolecular Pt-Pt distances in dinuclear Pt(II) complexes can be utilized as a guideline for the design of the double-decker dinuclear Pt(II) complexes with red and NIR tuned phosphorescence.

Automated summary

Red and near-infrared (NIR) phosphorescent double-decker dinuclear Pt(II) complexes were synthesized and characterized for their structural and spectroscopic properties. The complexes were found to exist as racemic mixtures with different intramolecular Pt-Pt distances controlled by the electronic characteristics of the C^N ligands. The Pt-Pt distances significantly influenced the band gap energies and corresponding emission wavelengths of the complexes, suggesting a method to finely tune the phosphorescence of these Pt(II) complexes.