Abstract
In this paper we report the photophysical properties of a series of bis-tridentate RuII-complexes, based on the dqp-ligand (dqp = 2,6-di(quinolin-8-yl)pyridine), which display several microsecond long excited state lifetimes for triplet metal-to-ligand charge transfer (3MLCT) at room temperature. Temperature dependence of the excited state lifetimes for [Ru(dqp)2]2+ and [Ru(dqp)(ttpy)]2+ (ttpy = 4′-tolyl-2,2′:6′,2′′-terpyridine) is reported and radiative and non-radiative rate constants for the whole series are reported and discussed. We can confirm previous assumptions that the near-octahedricity of the bis-dqp complexes dramatically slows down activated decay at room temperature, as compared to most other and less long-lived bis-tridentate RuII-complexes, such as [Ru(tpy)2]2+ with τ = 0.25 ns at room temperature (tpy = 2,2′:6′,2′′-terpyridine). Moreover, the direct non-radiative decay to the ground state is comparatively slow for ∼700 nm room-temperature emission when considering the energy-gap law. Analysis of the 77 K emission spectra suggests that this effect is not primarily due to smaller excited state distortion than that for comparable complexes. Instead, an analysis of the photophysical parameters suggests a weaker singlet-triplet mixing in the MLCT state, which slows down both radiative and non-radiative decay.
| Original language | English |
|---|---|
| Pages (from-to) | 13314-13321 |
| Number of pages | 8 |
| Journal | Dalton Transactions |
| Volume | 46 |
| Issue number | 39 |
| DOIs | |
| Publication status | Published - Jan 1 2017 |
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ASJC Scopus subject areas
- Inorganic Chemistry
Cite this
Microsecond 3MLCT excited state lifetimes in bis-tridentate Ru(II)-complexes : Significant reductions of non-radiative rate constants. / Abrahamsson, Maria; Becker, Hans Christian; Hammarström, Leif.
In: Dalton Transactions, Vol. 46, No. 39, 01.01.2017, p. 13314-13321.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Microsecond 3MLCT excited state lifetimes in bis-tridentate Ru(II)-complexes
T2 - Significant reductions of non-radiative rate constants
AU - Abrahamsson, Maria
AU - Becker, Hans Christian
AU - Hammarström, Leif
PY - 2017/1/1
Y1 - 2017/1/1
N2 - In this paper we report the photophysical properties of a series of bis-tridentate RuII-complexes, based on the dqp-ligand (dqp = 2,6-di(quinolin-8-yl)pyridine), which display several microsecond long excited state lifetimes for triplet metal-to-ligand charge transfer (3MLCT) at room temperature. Temperature dependence of the excited state lifetimes for [Ru(dqp)2]2+ and [Ru(dqp)(ttpy)]2+ (ttpy = 4′-tolyl-2,2′:6′,2′′-terpyridine) is reported and radiative and non-radiative rate constants for the whole series are reported and discussed. We can confirm previous assumptions that the near-octahedricity of the bis-dqp complexes dramatically slows down activated decay at room temperature, as compared to most other and less long-lived bis-tridentate RuII-complexes, such as [Ru(tpy)2]2+ with τ = 0.25 ns at room temperature (tpy = 2,2′:6′,2′′-terpyridine). Moreover, the direct non-radiative decay to the ground state is comparatively slow for ∼700 nm room-temperature emission when considering the energy-gap law. Analysis of the 77 K emission spectra suggests that this effect is not primarily due to smaller excited state distortion than that for comparable complexes. Instead, an analysis of the photophysical parameters suggests a weaker singlet-triplet mixing in the MLCT state, which slows down both radiative and non-radiative decay.
AB - In this paper we report the photophysical properties of a series of bis-tridentate RuII-complexes, based on the dqp-ligand (dqp = 2,6-di(quinolin-8-yl)pyridine), which display several microsecond long excited state lifetimes for triplet metal-to-ligand charge transfer (3MLCT) at room temperature. Temperature dependence of the excited state lifetimes for [Ru(dqp)2]2+ and [Ru(dqp)(ttpy)]2+ (ttpy = 4′-tolyl-2,2′:6′,2′′-terpyridine) is reported and radiative and non-radiative rate constants for the whole series are reported and discussed. We can confirm previous assumptions that the near-octahedricity of the bis-dqp complexes dramatically slows down activated decay at room temperature, as compared to most other and less long-lived bis-tridentate RuII-complexes, such as [Ru(tpy)2]2+ with τ = 0.25 ns at room temperature (tpy = 2,2′:6′,2′′-terpyridine). Moreover, the direct non-radiative decay to the ground state is comparatively slow for ∼700 nm room-temperature emission when considering the energy-gap law. Analysis of the 77 K emission spectra suggests that this effect is not primarily due to smaller excited state distortion than that for comparable complexes. Instead, an analysis of the photophysical parameters suggests a weaker singlet-triplet mixing in the MLCT state, which slows down both radiative and non-radiative decay.
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U2 - 10.1039/c7dt02437a
DO - 10.1039/c7dt02437a
M3 - Article
VL - 46
SP - 13314
EP - 13321
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1477-9226
IS - 39
ER -