Luminescence probe studies of ionomers. 3. Distribution of decay rate constants for tris(bipyridyl)ruthenium(II) in Nafion membranes

A Fluorescent Probe Investigation of the Origin of Superselectivity in Perfluorinated Ionomer Membranes

“…The authors concluded that the probe molecule is located at the interface of the fluorocarbon and the water exchange site region. In a further study, Colon and Martin showed that the initial tris(2,2‘-bipyridyl)ruthenium(II) ions to exchange into the ionomer occupy the sites of lowest water activity and that the probe molecule can take up to one month to reach an equilibrium environment within the polymer phase …”

“…A number of fluorescent probes have proved to be useful in the study of these ionomer membrane systems. − The two fluorescent probes that are used most extensively (and which are used in this study) are pyrene (and pyrene derivatives) and tris(2,2‘-bipyridyl)ruthenium(II) ion. The polarity of the local environment of pyrene can be determined by examination of the relative intensities of the principal vibronic bands of pyrene's emission spectrum, since the symmetry-forbidden bands show marked intensity enhancements under the influence of solvent polarity .…”

“…In a further study, Colon and Martin showed that the initial tris(2,2′-bipyridyl)ruthenium(II) ions to exchange into the ionomer occupy the sites of lowest water activity and that the probe molecule can take up to one month to reach an equilibrium environment within the polymer phase. 24 In this study the fluorescent probes pyrene and Ru-(bpy) 3 2+ are used to determine the location of ions within the polymer structure. The local environment of these probes in the ionomers is first examined to determine their location within the phase-separated structure and to note differences among the polymer types.…”

Spectroelectrochemical Sensor for Technetium Applicable to the Vadose Zone

“…To excite the fluorescence we used the evanescent wave mode of excitation. Using the HeCd laser line at 441.6 nm, the fluorescence [9][10][11][12][13][14] of Ru(bpy) 3 2+ can be easily excited and measured by collecting fluorescence from a single fluorescent spot on the top side of the MIR optic. For fluorescence data acquisition, the end of a fiber optic was butted up against a single spot and the fluorescence collected was dispersed by a monochromator and detected with a phototube with photon counting.…”

Size dependent ion-exchange of large mixed-metal complexes into Nafion® membranes

“…In this study, Nafion ® is used as a matrix to host photocatalytic complexes. [27][28][29] This ionomer has been shown to demonstrate a remarkable affinity for large hydrophobic cationic molecules, 1,[30][31][32] and as such, it is an ideal, thin film substrate for immobilizing large metal complexes suitable for artificial leaf applications. Given the unique ionic domain morphology of Nafion ® and the large dimensions of the mixed-metal complexes used in this study, it is important to evaluate the size dependent absorption behavior of this guesthost system.…”