Cyclometalated Platinum(IV) Compounds That Exhibit High Quantum Yields When Doped in PMMA Films

Cyclometalated platinum(IV) compounds containing both an anionic C'̂'N-thiophene-derived chelating iminic ligand and an isocyanide ligand were synthesized. The reaction of the Br–C'̂'N ligand with [Pt2Me4(μ-SMe2)2] afforded a platinum(IV) species with an SMe2 (dms) ligand that was easily substituted by several isocyanide ligands (2-naphthyl, adamantyl, 2,6-dimethylphenyl, para-toluenesulfonylmethyl). The compounds were characterized by multinuclear NMR spectroscopy, IR spectroscopy, and single-crystal X-ray diffraction (SCXRD). Their photophysical properties were explored using UV/vis, emission, and transient absorption (TA) spectroscopies. The emission spectra in solution of the platinum(IV) compounds show multiple emission peaks. The quantum yields of the compounds were measured as solutions, as solid samples, and as dopants in PMMA films. The quantum yield values obtained for the PMMA film samples were approximately an order of magnitude greater than those obtained in DCM solution. DFT and TDDFT calculations were performed, and the results were compared to the observed spectroscopic and crystallographic properties of the new complexes.