Synthesis, characterization and photophysical properties of new cyclometallated platinum(II) complexes with pyrazolonate ancillary ligand

New cyclometalated platinum(II) complexes with pyrazolonate ancillary ligand (ppy)Pt(pmip) (1) and (dfppy)Pt(pmip) (2) (ppy = 2-phenylpyridine, dfppy = (4,6-difluorophenyl)pyridine, Hpmip = 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) were synthesized and structurally characterized. Both compounds revealed square-planar geometry. The crystal cell of 1 was found to contain the monomer molecules of platinum compound whereas dimer molecules of 2 with short Pt⋯Pt contacts of 3.2217(3) Å were observed in the crystal cell of 2. Photophysical properties of 1 and 2 were investigated in detail. The highly resolved photoluminesence spectra of the platinum complexes in solution contain emission bands in the region of 470–550 nm attributed to monomer compounds 1 and 2. The triplet-state energies of 1 and 2 obtained from DFT calculations agree very well with the experimental data. In the crystalline state complex 2 revealed excimer emission as a structureless broad band at ca. 584 nm related to dimer molecules of platinum compound presented in the crystals.

New cyclometalated platinum(II) complexes with pyrazolonate ancillary ligand were synthesized and structurally characterized. Their electrochemical and photophysical properties were investigated and DFT calculations were performed.Figure optionsDownload as PowerPoint slideHighlights
► New cyclometalated platinum(II) complexes with pyrazolonate ancillary ligand.
► The compounds are luminescent at room temperature both in solution and in solid state.
► X-ray analysis, electrochemical study and DFT calculations were performed.
► Computational study agree very well with the experimental data.