The Reasons for Ligand‐Dependent Quantum Yields and Absorption Spectrum of Four Polypyridylruthenium(II) Complexes with a Tetrazolate‐Based Ligand: TDDFT Study

Abstract

The quantum yield, lifetime, and absorption spectrum of four [Ru(bpy) 2 L] + [where bpy is 2,2Ј-bipyridyl; L is represented by the deprotonated form of 2-(1H-tetrazol-5-yl)pyridine (L1) or 2-(1H-tetrazol-5-yl)pyrazine (L2)], as well as their methylated complexes [Ru(bpy) 2 LMe] 2+ (RuL1Me and RuL2Me) are closely ligand dependent. In this paper, density functional theory (DFT) and time-dependent DFT (TDDFT) were performed to compare the above properties among these complexes. The calculated results reveal that the replacement of pyridine by pyrazine or the attachment of a CH 3 group to the tetrazolate ring greatly increases the π-accepting ability of the ancillary ligands. The stronger π-accepting ability of the ancillary ligands in RuL2 results in stronger interaction with

DFT and Time-dependant DFT Investigation of eLectronic Structure, Phosphorescence and Electroluminescence Properties of Iridium (III) Quinoxaline Complexes

“…This can be attributed to the presence of stronger π-electron accepting fpmqx ligand: the σ-electron donating properties of phenyl ring (ph), together with the stronger π-accepting ability of the quinoxaline (qux) fragment, may provide a synergism of electron delocalization so that the electron density is transferred from phenyl ring to the metal ion and back to the quinoxaline side, thus enhancing the chelate interaction. 18 This stronger metal-ligand interaction is significantly important to reduce the nonemissive transition channel and improve the phosphorescent quantum yields. Because the strengthened metal-ligand interaction is a critical factor to increase 3 MLCT character and therefore shorten the phosphorescence lifetime, which can partially remove the possibility of fast decay.…”

“…18 As shown in Table S2, the 3 MLCT composition can be obtained by MLCT%=M(occupied)%-M(unoccupied)%. Therefore, the calculated 3 MLCT characters for 1-3 are 10.4, 11.4 and 22.2%, respectively, which is consistent with the increased trend of k r value for 1-3 in Table 7.…”

Density functional theory and time‐dependent density functional theory study on a series of iridium complexes with tetraphenylimidodiphosphinate ligand

“…[ [39][40][41][42][43] The M062x functional together with the same basis set mentioned previously were adopted to evaluate the emission nature. [44] Furthermore, the stable configurations of these complexes can be confirmed by frequency analysis, in which no imaginary frequency was found for all configurations at the energy minima.…”

Effect of phenylamine moiety on the structure, optical properties, and phosphorescence efficiencies of some red-emitting iridium(III) complexes: A theoretical study

“…On the basis of the above discussion, we notice that the participaiton of MLCT in the lower-energy region of 2a and 2b become larger than 1a-c. The MLCT is very efficient to collect light energy participation of metals[51][52][53], thus 2a and 2b are hoped to have higher luminescene quantum yields than experimental synthesized 1c as well as our designed 1a and 1b. For 1a, 1b, 2a, 2c, their high-energy absorption peaks are located at 338.8nm (contributed by HOMO-4→LUMO+2 transition) 349nm (contributed by HOMO→LUMO+4/LUMO+5 transition) 335.6nm (contributed by HOMO-6→LUMO transition) and 314.3nm (contributed by HOMO→LUMO+12 and HOMO→LUMO+13 transitions), respectively.…”