Synthesis, characterization, photophysical and electrochemical properties of fac-tricarbonyl(4,7-dichloro-1,10-phenanthroline)rhenium(I) complexes

The fac-[Re(CO)3Cl(Cl2phen)] and fac-[Re(CO)3(py)(Cl2phen)]PF6 complexes were synthesized, purified and characterized by 1H NMR, UV–Vis and IR spectroscopies and both photophysical and electrochemical behaviors were investigated. The electronic absorption spectra exhibit two main absorption bands: the higher energy band, which was assigned to IL, and the lower energy band, assigned to MLCT. The fac-[ReCl(Cl2phen)(CO)3] and fac-[Re(py)(Cl2phen)(CO)3]PF6 complexes showed emission at room temperature in both CH3CN solution (λmax = 640 nm, ϕ = 0.0027; λmax = 590 nm, ϕ = 0.055) and rigid media (λmax = 590 nm, λmax = 535 nm in PMMA) arising from the lowest lying metal to ligand charge transfer (3MLCTRe→Cl2phen) excited state. Additionally, the PVK emission band is almost completely quenched in the presence of 4% rhenium(I) complex. Both compounds showed metal-centered oxidation, Re(I) → (II), and ligand-based reduction, Cl2phen → Cl2phen∗−, in CH2Cl2 solution. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels of both complexes were estimated. The electrochemical and emission properties indicate a potential application of the rhenium(I) compounds in OLED devices.

The fac-[Re(CO)3Cl(Cl2phen)] and fac-[Re(CO)3(py)(Cl2phen)]PF6 complexes were synthesized, characterized and photophysical and electrochemical behaviors were investigated. Both complexes showed emission at room temperature in CH3CN solution and in rigid media arising from the 3MLCTRe→Cl2phen excited state. The electrochemical and emission properties indicate a potential application of these compounds in OLED devices.Figure optionsDownload as PowerPoint slide