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Steady-State and Time-Resolved Investigations on Pyrene-Based Chemosensors

J. Fernández-Lodeiro, C. Núñez, C.S. De Castro, E. Bértolo, J.S. Seixas De Melo, J.L. Capelo, C. Lodeiro, Catherine De Castro Orcid Logo

Inorganic Chemistry, Volume: 52, Issue: 1, Pages: 121 - 129

Swansea University Author: Catherine De Castro Orcid Logo

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DOI (Published version): 10.1021/ic301365y

Abstract

Two novel fluorescent probes bearing a single (P) and two (a podand-like structure, L) pyrene units derived from 1,5-bis(2-aminophenoxy)-3-oxopentane have been synthesized and investigated in dioxane using UV–vis absorption, and steady-state and time-resolved (in a picosecond time scale) emission sp...

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Published in: Inorganic Chemistry
ISSN: 0020-1669 1520-510X
Published: 2013
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URI: https://cronfa.swan.ac.uk/Record/cronfa31931
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Abstract: Two novel fluorescent probes bearing a single (P) and two (a podand-like structure, L) pyrene units derived from 1,5-bis(2-aminophenoxy)-3-oxopentane have been synthesized and investigated in dioxane using UV–vis absorption, and steady-state and time-resolved (in a picosecond time scale) emission spectroscopy; in the gas phase, matrix-assisted laser desorption ionization mass spectrometry was employed. In dioxane, the absorption and emission spectra of P present a unique band with maxima at 361 and 392 nm, which have been associated with the monomer absorption and emission bands, respectively. In dioxane, for compound L, an additional band with a maximum at ∼525 nm is observed; upon the addition of water, an emissive band (with maxima varying from 405 to 490 nm) appears in both P and L spectra; this is discussed in terms of the emission of a species with charge character. Upon metal addition (Cu2+, Zn2+, and Ag+) to P, a gradual quenching effect of the monomer emission is observed and found to be more pronounced with Cu2+. In the case of L, upon the addition of metal cations, the long emission band (∼550 nm) decreases and the monomer emission band increases (with an isoemissive point at ∼450 nm) and no evidence for the intermediate band (at ∼405–490 nm) now exists. Time-resolved data in dioxane/water mixtures showed that for P and L these two fit double- and triple-exponential decay laws, respectively. With P, this has been attributed to a two-state system, which involves the monomer and a charged species, with its emission maxima varying with the polarity of the media (here mirrored by its dielectric constant), which can potentially be addressed to an exciplex-like species, whereas with L, it has been attributed to a three-state system involving, in addition to these two species, an excimer. From absorption and fluorescence excitation and time-resolved data, evidence is given for the presence of intramolecular dimer formation in the ground state.
College: Faculty of Science and Engineering
Issue: 1
Start Page: 121
End Page: 129