Book Reviews

Novel N^C^N-cyclometallated platinum complexes with acetylide co-ligands as efficient phosphors for OLEDs

“…7 In particular, the substitution of weak-field halide co-ligands (X) by strong-field cyanides or, even better, by acetylides in complexes of the type Pt(N^N)X 2 and [Pt(N^N^N)X] + has shown how an increase in the ligand field strength of the ancillary ligand promotes luminescence. 7 Acetylides are more attractive than cyanides, since the latter tend to lead to a drop in the energy of metal-centered orbitals. The beneficial effect of displacing d-d states to high energy is then compromised by a reduced metal character in the excited state, leading to reduced radiative rate constants.…”

“…7 Meanwhile, terdentate ligands offer an advantage over bidentate ligands in that the additional rigidity they impart inhibits the D 2d distortion that bis-bidentate complexes can undergo through twisting of the two planes relative to one another. 12 Much work has been carried out on cyclometallated Pt(II) complexes with N^N^C-coordinating ligands such as cyclometallated 6-phenyl-2,2 0 -bipyridine, whose Pt(II) chloro complex exhibits, in solution at room temperature, an emission quantum yield of 0.025 (ref.…”

“…2,6 Although iridium(III) complexes are predominant in this field, increasing attention is focused on platinum(II) complexes, particularly due to their propensity to undergo face-to-face bimolecular interactions leading to excimeric or aggregate emissions. 7 In the last few years, several families of Pt(II) complexes have been discovered that are brightly luminescent in solution at room temperature, and a number of investigations have shed light on the factors that govern their luminescence efficiencies. 7 Strong-field ligands or co-ligands tend to favour emission efficiencies, as they raise the energies of otherwise deactivating d-d states, making them thermally inaccessible and thus reducing non-radiative decay pathways.…”

“…7 In the last few years, several families of Pt(II) complexes have been discovered that are brightly luminescent in solution at room temperature, and a number of investigations have shed light on the factors that govern their luminescence efficiencies. 7 Strong-field ligands or co-ligands tend to favour emission efficiencies, as they raise the energies of otherwise deactivating d-d states, making them thermally inaccessible and thus reducing non-radiative decay pathways. 7 In particular, the substitution of weak-field halide co-ligands (X) by strong-field cyanides or, even better, by acetylides in complexes of the type Pt(N^N)X 2 and [Pt(N^N^N)X] + has shown how an increase in the ligand field strength of the ancillary ligand promotes luminescence.…”

“…7 Strong-field ligands or co-ligands tend to favour emission efficiencies, as they raise the energies of otherwise deactivating d-d states, making them thermally inaccessible and thus reducing non-radiative decay pathways. 7 In particular, the substitution of weak-field halide co-ligands (X) by strong-field cyanides or, even better, by acetylides in complexes of the type Pt(N^N)X 2 and [Pt(N^N^N)X] + has shown how an increase in the ligand field strength of the ancillary ligand promotes luminescence. 7 Acetylides are more attractive than cyanides, since the latter tend to lead to a drop in the energy of metal-centered orbitals.…”