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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2072

Title: Tuning Fluorescence Properties of 2,2’-Bipyridine Using Metal Cations
Authors: Aklilu, Guale
Advisors: Dr. Mesfin Redi
Keywords: Science in Chemistry
Copyright: Jul-2010
Date Added: 2-May-2012
Publisher: ADDIS ABABA UNIVERSITY
Abstract: The steady state absorption, fluorescence excitation and emission spectra of 2,2’-bipyridine have been studied in polar solvents. Absorption spectra are almost independent of solvent polarity. The dependence of fluorescence emission on excitation wavelength was observed in acetonitrile and p-dioxane but independent of excitation energy in tetrahydrofuran. Addition of metal ion and varying pH of the solution shifted the absorption band to the red-edge and intensity change was observed in fluorescence excitation spectra. Corresponding excitation bands of the metal free conformers were compared to the stable conformers of metal-chelated and protonated 2,2’-bipyridine. Study of the rotational profile of 2,2’-bipyridine at DFT/B3LYP/STO-3G level shows two energy minima corresponding to two conformations of different energy, cis/trans structures, with barrier to rotation greater than the room temperature thermal energy. It is shown that distributions of energetically different conformers of the molecule (cis/trans) in the ground state are responsible for the dual fluorescence behavior of the systems.
URI: http://hdl.handle.net/123456789/2072
Appears in:Thesis - Chemistry

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