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Title

Tuning the Photophysical Behavior of Luminescent Cyclam Derivatives by Cation Binding and Excited State Redox Potential

Authors
Moore, Evan G.
Bernhardt, Paul V.
Fürstenberg, Alexandre
Riley, Mark J.
Smith, Trevor A.
Published in Journal of Physical Chemistry. A. 2005, vol. 109, no. 17, p. 3788-3796
Abstract The emission from two photoactive 14-membered macrocyclic ligands, 6-((naphthalen-1-ylmethyl)-amino)-trans-6,13-dimethyl-13-amino-1,4,8,11-tetraaza-cyclotetradecane (L1) and 6-((anthracen-9-ylmethyl)-amino)-trans-6,13-dimethyl-13-amino-1,4,8,11-tetraaza-cyclotetradecane (L2) is strongly quenched by a photoinduced electron transfer (PET) mechanism involving amine lone pairs as electron donors. Time-correlated single photon counting (TCSPC), multiplex transient grating (TG), and fluorescence upconversion (FU) measurements were performed to characterize this quenching mechanism. Upon complexation with the redox inactive metal ion, Zn(II), the emission of the ligands is dramatically altered, with a significant increase in the fluorescence quantum yields due to coordination-induced deactivation of the macrocyclic amine lone pair electron donors. For [ZnL2]2+, the substituted exocyclic amine nitrogen, which is not coordinated to the metal ion, does not quench the fluorescence due to an inductive effect of the proximal divalent metal ion that raises the ionization potential. However, for [ZnL1]2+, the naphthalene chromophore is a sufficiently strong excited-state oxidant for PET quenching to occur.
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Research group Groupe Vauthey
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MOORE, Evan G. et al. Tuning the Photophysical Behavior of Luminescent Cyclam Derivatives by Cation Binding and Excited State Redox Potential. In: Journal of Physical Chemistry. A, 2005, vol. 109, n° 17, p. 3788-3796. https://archive-ouverte.unige.ch/unige:3276

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Deposited on : 2009-09-21

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