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Photophysical properties of the photosensitizer [Ru(bpy)2(5-CNphen)]2+ and intramolecular quenching by complexation of Cu(II)

Paper ID Volume ID Publish Year Pages File Format Full-Text
29110 44122 2006 5 PDF Available
Title
Photophysical properties of the photosensitizer [Ru(bpy)2(5-CNphen)]2+ and intramolecular quenching by complexation of Cu(II)
Abstract

The lifetime of the 3MLCT emitting state of [Ru(bpy)2(5-CNphen)]2+ (bpy = 2,2′-bipyridine, 5-CNphen = 5-cyano-1,10-phenanthroline) has been determined in CH3CN by flash photolysis and TCSPC techniques. The obtained value, τ = 2.2 μs, points to its potential use as a photosensitizer in molecular devices. The transient spectrum shows that this excited state can be formulated as a metal-to-ligand charge transfer state. Static and dynamic quenching of the complex luminescence by Cu2+ ions is observed. The static and dynamic components were evaluated by measuring emission intensities and lifetimes at different [Cu2+]. The combined quenching results point to a strong ground state complexation of Cu2+ (Keq = 7500 M−1 for 1:1 complex) with the nitrile group of 5-CNphen. At high [Cu2+], a short-lived component of the decay has been detected, with ket = 4.0 × 109 s−1. This value is compared to the electron transfer rate constant in the encounter complex of the bimolecular quenching, which was obtained from the dynamic quenching rate constant.

Keywords
Ruthenium complex photophysics; Intramolecular photoinduced electron transfer
First Page Preview
Photophysical properties of the photosensitizer [Ru(bpy)2(5-CNphen)]2+ and intramolecular quenching by complexation of Cu(II)
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 181, Issue 1, 5 July 2006, Pages 28–32
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering