Molecular complexes of crown ethers. Part 3. Effect of cations on charge transfer complexes with TCNE |
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| Authors: | Salman R Salman Gazi A W Derwish Sabri M H Al-Marsoumi |
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| Institution: | (1) Chemistry Department, College of Science, University of Yarmouk, Irbid, Jordan;(2) Chemistry Department, College of Science, University of Jordan, Amman, Jordan;(3) Department of Industrial Chemistry, Anbar Technical Institute, Saqlawia, Anbar, Iraq |
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| Abstract: | The intermolecular charge transfer complexes (CT) of two crown ethers (CE), viz, B15C5 and DB18C6 (as donors), and tetracyanoethylene (TCNE), as acceptor, were studied in the UV-visible region in dichloroethane (DCE), at 298.2 K. The sequence of addition of the cation was varied in the case of B15C5 such that in one system the sequence was (CE+Cation)+TCNE and in the other (CE+TCNE)+cation. These two systems were found to be non-interchangeable, even under reflux conditions, giving differentK
c
values which were explained as being due to the different geometries of the CE. For the first sequence, the values most affected depended on the fit of the metal cation with the ether cavity, thus in B15C5, Na+ showed the greatest effect, while for DB18C6 it was K+. |
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| Keywords: | Crown ethers tetracyanoethylene UV-visible spectroscopy formation constant effect of cations on formation constant |
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