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Title: Luminescent Nafion membranes dyed with ruthenium(II) complexes as sensing materials for dissolved oxygen

Abstract

The absorption spectroscopy, photophysics, and dioxygen quenching of [RuL{sub 3}]{sup 2+} luminescent probes, where L stands for 2,2{prime}-bipyridine, 1,10-phenanthroline, 5-octadecanamide-1,10-phenanthroline, and 4,7-diphenyl-1,10-phenanthroline (dip), electrostatically loaded onto Nafion ionomer membrane have been investigated in air and in organic solvents and water, with the aim of developing rugged materials for optical sensing of molecular oxygen. The significant differences in size and hydrophobicity of the Ru(II) dyes have been used to probe their location within the perfluorinated ionomer pore network, as well as to gain insight into the oxygen accessibility to its microcrystalline and interfacial domains. While the absorption maximums of the probes (444--458nm) remain relative unchanged, their emission wavelengths (578--622 nm) are extremely sensitive to the degree of Nafion swelling by the solvent. This feature has been characterized by measuring the density (1.19--2.04 g cm{sup {minus}3}) of the solvent-saturated ionomer and the mass and volume fractions of solvents (0.0--0.7) uptake by the original acidic Nafion and Li{sup +}-, Na{sup +}-, or K{sup +}-exchanged films. The excited-state lifetimes of the [RuL{sub 3}]{sup 2+} complexes (0.03--4.9{micro}s) reflect important variations of the microenvironment around the luminescent probes, which are rationalized in terms of their location and oxygen accessibility when loaded onto the polysulfonated material. Emissionmore » quenching rate constants of 1.7 {+-} 0.3 M{sup {minus}1}s{sup {minus}1} have been measured for the [Ru(dip){sub 3}]{sup 2+}-dyed films dipped in methanol; their oxygen sensitivity turns out to be independent of the Ru(II) loading and counterion of Nafion. Highly oxygen-sensitive luminescent membranes, suitable for continuous monitoring in organic solvents, water, or gas phase, have been prepared by immobilization of [Ru(dip){sub 3}]{sup 2+} indicator in 178-{micro}m thick Nafion, with response times below 1.5 min. Nevertheless, a slow evolution of the oxygen response over 1 week has been detected for very solvent-swollen membranes; some ways of minimizing such an effect are also given.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Univ. Complutense de Madrid (ES)
OSTI Identifier:
20000009
Resource Type:
Journal Article
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 15; Journal Issue: 19; Other Information: PBD: 14 Sep 1999; Journal ID: ISSN 0743-7463
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 54 ENVIRONMENTAL SCIENCES; MEASURING INSTRUMENTS; PHOTOLUMINESCENCE; DISSOLVED GASES; OXYGEN; RUTHENIUM COMPLEXES; ENVIRONMENTAL MATERIALS; WASTE WATER

Citation Formats

Garcia-Fresnadillo, D., Orellana, G., Marazuela, M.D., and Moreno-Bondi, M.C. Luminescent Nafion membranes dyed with ruthenium(II) complexes as sensing materials for dissolved oxygen. United States: N. p., 1999. Web. doi:10.1021/la981689c.
Garcia-Fresnadillo, D., Orellana, G., Marazuela, M.D., & Moreno-Bondi, M.C. Luminescent Nafion membranes dyed with ruthenium(II) complexes as sensing materials for dissolved oxygen. United States. doi:10.1021/la981689c.
Garcia-Fresnadillo, D., Orellana, G., Marazuela, M.D., and Moreno-Bondi, M.C. Tue . "Luminescent Nafion membranes dyed with ruthenium(II) complexes as sensing materials for dissolved oxygen". United States. doi:10.1021/la981689c.
@article{osti_20000009,
title = {Luminescent Nafion membranes dyed with ruthenium(II) complexes as sensing materials for dissolved oxygen},
author = {Garcia-Fresnadillo, D. and Orellana, G. and Marazuela, M.D. and Moreno-Bondi, M.C.},
abstractNote = {The absorption spectroscopy, photophysics, and dioxygen quenching of [RuL{sub 3}]{sup 2+} luminescent probes, where L stands for 2,2{prime}-bipyridine, 1,10-phenanthroline, 5-octadecanamide-1,10-phenanthroline, and 4,7-diphenyl-1,10-phenanthroline (dip), electrostatically loaded onto Nafion ionomer membrane have been investigated in air and in organic solvents and water, with the aim of developing rugged materials for optical sensing of molecular oxygen. The significant differences in size and hydrophobicity of the Ru(II) dyes have been used to probe their location within the perfluorinated ionomer pore network, as well as to gain insight into the oxygen accessibility to its microcrystalline and interfacial domains. While the absorption maximums of the probes (444--458nm) remain relative unchanged, their emission wavelengths (578--622 nm) are extremely sensitive to the degree of Nafion swelling by the solvent. This feature has been characterized by measuring the density (1.19--2.04 g cm{sup {minus}3}) of the solvent-saturated ionomer and the mass and volume fractions of solvents (0.0--0.7) uptake by the original acidic Nafion and Li{sup +}-, Na{sup +}-, or K{sup +}-exchanged films. The excited-state lifetimes of the [RuL{sub 3}]{sup 2+} complexes (0.03--4.9{micro}s) reflect important variations of the microenvironment around the luminescent probes, which are rationalized in terms of their location and oxygen accessibility when loaded onto the polysulfonated material. Emission quenching rate constants of 1.7 {+-} 0.3 M{sup {minus}1}s{sup {minus}1} have been measured for the [Ru(dip){sub 3}]{sup 2+}-dyed films dipped in methanol; their oxygen sensitivity turns out to be independent of the Ru(II) loading and counterion of Nafion. Highly oxygen-sensitive luminescent membranes, suitable for continuous monitoring in organic solvents, water, or gas phase, have been prepared by immobilization of [Ru(dip){sub 3}]{sup 2+} indicator in 178-{micro}m thick Nafion, with response times below 1.5 min. Nevertheless, a slow evolution of the oxygen response over 1 week has been detected for very solvent-swollen membranes; some ways of minimizing such an effect are also given.},
doi = {10.1021/la981689c},
journal = {Langmuir},
issn = {0743-7463},
number = 19,
volume = 15,
place = {United States},
year = {1999},
month = {9}
}