Electron‐donor substituents on the dppz‐based ligands to control luminescence from dark to bright emissive state in Ir(III) complexes

Abstract

Dppz-based Ir(III) complexes show a competition between dark and bright excited states. Paulina Dreyse and colleagues in e26167 used DFT/TD-DFT to determine geometrical and photophysical properties, and the possible applicability of these systems as new luminescent materials in Light Emitting Electrochemical Cells (LECs). The study found an improved radiative decay (bright) in presence of electron-donor substituents.

Towards efficient Ir(iii) anticancer photodynamic therapy agents by extending π-conjugation on N^N ligands

“…The topology and energy of the MOs were also calculated for the ground electronic state (S 0 ) and are shown in Scheme 2 and Table S6. † In good agreement with the literature, [37][38][39] the HOMOs are composed of a mixture of orbitals from the iridium centre (d π ) and from the two phenyl rings of the C^N ligands (π orbitals). Moreover, all of them exhibit a π-antibonding nature at the Ir-C phenyl interfaces.…”

“…Also as expected, the LUMOs are distributed over the corresponding N^N ligand. 39 As shown in Scheme 2, the energy values calculated for the LUMO of [IrL1] + and [IrL2] + are nearly the same. However, the LUMO energies are stabilized on going from [IrL2] + (−2.04 eV) to [IrL5] + (−2.89 eV) as the number of π-conjugated rings in the N^N ligand is gradually extended from [IrL2] + to [IrL5] + .…”

“…Also as expected, the LUMOs are distributed over the corresponding N^N ligand. 39 As shown in Scheme 2, the energy values calculated for the LUMO of The nature of the emitting excited state was investigated using the time-dependent DFT (TD-DFT) approach. The three lowest-energy triplet excited states (T 1 , T 2 and T 3 ) were calculated (see Table S7 †).…”

Inert cationic iridium(iii) complexes with phenanthroline-based ligands: application in antimicrobial inactivation of multidrug-resistant bacterial strains

“…This characteristic is common for other Ir(III) compounds with the dppz ligand. 31,32,36 The decrease of the emission intensity of the complexes with respect to highly emissive Ir1, could be explained by the increase of the non-radiative process due to the interaction of the solvent with the two uncoordinated basic nitrogens of the phenazine ligands. 37,38 Dppz-based complexes possess two triplet excited states: a "bright" (emissive) 3 MLCT state involving the proximal bipyridine (bpy) portion of the dppz ligand and a "dark" (non-emissive) 3 MLCT state involving the phenazine moiety of dppz distal to the metal.…”

Ru(II)-Dppz Derivatives and Their Interactions with DNA: Thirty Years and Counting

“…A wide variety of dppz-based complexes were designed, synthesized, and studied by modifying the bipyridine ancillary ligand or the dppz ligand [73][74][75][76][77][78], or changing the metal center to Re [79][80][81][82], Co [83,84], Cu [85,86], Rh [87][88][89][90], Os [91,92], Pt [31,[93][94][95], and Ir [96][97][98] cations.…”