Interrogation of the photophysics of a highly emissive bistridentate Ru(II) complex on interaction with crown-shaped polyoxometalate K28Li5H7[P8W48O184].
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| Title: | Interrogation of the photophysics of a highly emissive bistridentate Ru(II) complex on interaction with crown-shaped polyoxometalate K28Li5H7[P8W48O184]. |
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| Authors: | Sakthinathan, Indherjith1,2 (AUTHOR) indherjith.sakthinathan@dkit.ie, Burke, Christopher3 (AUTHOR), McCormac, Timothy1 (AUTHOR), Keyes, Tia E.1,3 (AUTHOR) tia.keyes@dcu.ie |
| Source: | Polyhedron. Jun2026, Vol. 293, pN.PAG-N.PAG. 1p. |
| Subjects: | Ruthenium compounds, Polyoxometalates, Charge transfer, Luminescence quenching, Photoactivation, Spectrometry, Photoreduction |
| Abstract: | Ruthenium polypyridyl complexes are widely studied due to their strong light absorption, tunable emission, and rich redox chemistry. In this study, we investigate the photophysical properties of [Ru(bqp) 2 ]Cl 2 (bqp = 2,6-di(quinolin-8-yl)pyridine) in the presence of the crown-shaped polyoxometalate (POM) K 28 Li 5 H 7 [P 8 W 48 O 184 ].92H 2 0, shortly [P 8 W 48 O 184 ]40−, in acidic solution (0.1 M HCl). UV–visible spectroscopy reveals a broad MLCT absorption for [Ru(bqp) 2 ]2+ centred at 491 nm, while difference electronic spectroscopy upon titration with [P 8 W 48 O 184 ]40− (0.2–2 × 10−6 M) reveals a weak new charge-transfer band at ∼568 nm, indicating the subtle electronic communication between the two species. Steady-state luminescence measurements show efficient quenching of the 3MLCT [Ru(bqp) 2 ]2+ emission at 695 nm by [P 8 W 48 O 184 ]40− with near-complete extinction of emission observed at a molar ratio of 1:20 POM to Ru. Time-resolved fluorescence studies reveal a modest decrease in the excited-state lifetime, indicating a mixed static and dynamic quenching regime and a dynamic quenching constant of 2.9 × 105 M−1. The quenching mechanism is dominated by static quenching attributed to the formation of a ground-state Ru-POM complex. Upon visible-light irradiation (λ > 390 nm), spectroscopic changes confirm photoreduction of the POM, accompanied by a progressive loss of ligand-centred (280 nm) and MLCT (∼ 495 nm) absorption features of the Ru complex, indicating oxidative changes to the sensitiser. Our results demonstrate that [Ru(bqp) 2 ]2+ may serve as a visible-light sensitiser for POM photoreduction, highlighting how Ru-based photosensitisers can extend the redox chemistry of POM into the visible region, but that this activity can be accompanied by chemical modification to the sensitiser. The bis-tridentate ruthenium(II) complex [Ru(bqp) 2 ]2+ interacts with the crown-type polyoxometalate [P 8 W 48 O 184 ]40− under visible-light excitation. Steady-state and time-resolved spectroscopy demonstrate effective photoinduced electron transport, enabling POM photoreduction. The results show that [Ru(bqp) 2 ]2+ can act as a visible-light sensitiser, expanding polyoxometalate redox chemistry into the visible range. [Display omitted] [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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