Symmetry assignments of the lowest CT excited states of ruthenium (II) complexes via a proposed electronic coupling model

Abstract

Articles you may be interested inExchange coupling between ferromagnetic and antiferromagnetic layers via Ru and application for a linear magnetic field sensor J. Appl. Phys. 99, 08H703 (2006); 10.1063/1.2162507 Oscillator strengths for transitions involving excited states not lowest of their symmetry: Carbon I and fluorine II transitions J. Chem. Phys. 64, 4680 (1976); 10.1063/1.432052Oscillator strengths for transitions involving excited states not lowest of their symmetry oxygen I and oxygen II transitions Temperature dependence measurements of the decay times of the observed charge-transfer luminescence of three ruthenium (II) complexes indicate a manifold of decaying excited levels in thermal equilibrium. Relative energies and decay constants for each level have been derived from the data for the tris(2, 2' -bipyridine)ruthenium(II) and tris( 4, 4' -diphenyl-2, 2' -bipyridine)ruthenium(II) cations and for cis-dicyanobis(2, 2' ,bipyridine) ruthenium(II). An electronic coupling model has been proposed that satisfactorily rationalizes the experimental results and allows the levels to be symmetry labeled.

Photophysical Properties and OLED Applications of Phosphorescent Platinum(II) Schiff Base Complexes

“…Besides the direct determination of the ZFS parameters from highly resolved emission and excitation spectra, [12,16,17] it is possible to obtain these values from the temperature dependence of the emission decay time. Under the assumption of fast thermalization, the occupation dynamics of the excited states (triplet substates) involved in the emission process are governed by Equation (1), [12,[19][20][21] in which n i denotes the Boltzmann occupation number of state i, k i is the total rate constant for depopulation of state i. N is the total number of occupied excited states and k therm = 1/t therm is the rate constant for depopulation of the equilibrated system of excited states, that is, the inverse of the measured decay time.…”

A Theoretical Investigation into the Photophysical Properties of Ruthenium Polypyridine‐Type Complexes

“…They used it to fit the temperature dependence of the lifetime of [Ru-(bpy) 3 ] 2 + . [35] Their conclusion was that the emission arises from three states close in energy in thermal equilibrium: an A 1 lowest state, an E state nearly degenerated and an A 2 state about 0.01 eV higher. Spin labelling of these states was found to be wholly inappropriate.…”

“…Temperature dependence studies of the mean lifetime have also been performed to ascertain the energy level splittings of the decaying states in thermal equilibrium. [35] Another experimental technique providing information on the excited state is the study of flash-induced absorption change spectra. It gives some precious insight into the electronic spectra of the state generated from the singlet state by laser excitation followed by ultrafast intersystem crossing.…”

Analysis of the emitting states of an Ir(III) complex with strong blue emission

“…The obtained zero-field splitting (ZFS) between the three sublevels are large if interpreted the first two levels as A + E levels of a triplet state, and the higher level as a singlet level. 30 However, it has since become clear that all three sublevels are non-degenerate, with sharply resolved (width ~ 8 cm -1 ) electronic origins of sublevels I-III seen directly in the excitation and emission spectra of [Ir(ppy) 3 ] in dichloromethane at 1.5 K, and these levels shift but not split in magnetic fields of up to 12 Tesla (T). 20 The splitting of the triplet state into three non-degenerate sublevels requires a symmetry lower than the C 3 symmetry of the ground state.…”