Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5265697 | Tetrahedron Letters | 2013 | 6 Pages |
Abstract
The thiosemicarbazide receptors 1 and 2, containing three N-H donors (including a thiourea motif), have been synthesized and studied for their anion binding abilities. The recognition of 1 and 2 with various anions [AcOâ, Fâ, H2PO4â, SO42â and OHâ for 1; OAcâ and Fâ for 2] as their tetrabutylammonium salts was studied spectroscopically in CH3CN and EtOH. Significant changes were observed in the UV-vis absorption spectra of 1 which was red-shifted in both solvents when titrated with these anions. A dramatic colour change from yellow to red was also clearly observed. In contrast, the absorption changes for 2 were smaller with a colour change from colourless to yellow. These changes were determined to be due to deprotonation of the central N-H moiety (belonging to the thiourea) and not due to hydrogen bonding of these anions to the receptors. This was confirmed using single crystal X-ray crystallography, as crystals of 1 grown with TBAAc were found to correspond to the deprotonated structure 3.
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Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Komala Pandurangan, Jonathan A. Kitchen, Thorfinnur Gunnlaugsson,