Cyclometalated NHC Platinum(II) Complexes with β-Ketoiminate Ligands

Condensation of acetylacetone and two different bromo-alkylamines yields β-ketoimines that are used to alkylate 1-phenyl-1 H -imidazole. From the resulting imidazolium salts the corresponding platinum(II) complexes can be synthesized in a one-pot reaction. This new class of ligands combines a N -heterocyclic carbene and a β-ketoiminate to a tetradentate ligand that coordinates to the central platinum atom. The solid-state structure confirms the tetradentate coordination, while the investigation of the photophysical properties reveals emission maxima at 500 nm and 522 nm with quantum yields up to Φ = 12%. Their activity in the catalytic hydrosilylation gives additional insight into the properties of this novel class of cyclometalated complexes.