992-63-2Relevant academic research and scientific papers
Fluorescent but ‘choked’ multipodands: Ag(I) complexation and NMR studies
Singh, Prabhpreet
, p. 67 - 76 (2021)
Abstract: A series of fluorescent and non-fluorescent multipodands, substituted with donor S, N, and O heteroatoms, bridged to mesitylene and benzene core at 1, 3-, 1, 3, 5-, and 1, 2, 4, 5-positions have been synthesized and characterized. The liquid–liquid extraction experiment showed that non-fluorescent podands such as mono-, di-, tri-, and tetrapod exhibited excellent complexation abilities towards Ag+ ions. The tetrapodand (O, N) shows highest extraction of Ag+ (73%) and tetrapodand (S, N) shows the highest Ag+/Pb2+ selectivity (135). However, for fluorescent dipodands very weak complexation ability towards metal ions were observed likely due to steric crowding. Significantly, these fluorescent dipodands undergoes protonation at very low pH (ca. 1.0), reminiscent of acid stability—a structural feature of blue copper proteins. The NMR analysis of fluorescent podands showed that amine-appended anthracene moiety(ies) almost fills the podand cavity as lid, shifting most of the protons upfield (~ 0.5?ppm), thus causing acid stability. Graphic abstract: [Figure not available: see fulltext.].
