Multidentate Anion Receptors for Binding Glyphosate Dianion: Structure and Affinity. Issue 11 (17th March 2017)

• Record Type: Journal Article
• Authors: Kadam, Sandip A.; Haav, Kristjan; Toom, Lauri; Pung, Astrid; Mayeux, Charly; Leito, Ivo
• Is Part Of: European journal of organic chemistry. Issue 11(2017)
• Page Start: 1396
• Page End: 1406
• Publication Date: 2017-03-17
• Subjects: Glyphosate -- Anions -- Receptors -- Binding affinity -- Hydrogen bonds; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201601583
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : For the first time, the relationships between anion receptor structures and their glyphosate dianion (Gly 2– ) binding affinity have been investigated. For this purpose, 12 multidentate bis‐indolocarbazole, bis‐urea and bis‐carbazole based synthetic receptors were synthesized and their binding affinities towards Gly 2– were measured in H2 O/DMSO media (0.5 % to 20 % of H2 O). Computational geometries, as well as 1D and 2D NMR experiments were used to elucidate the structures of the complexes formed on binding of Gly 2– . As expected, binding affinity depends strongly on the spatial position of the binding moieties, which, in turn, depend on the spacer length and rigidity. However, the relationships are not straightforward and, in some cases, are counterintuitive. Evidence is presented that, for several receptors, binding occurs through the phosphonate moiety only. One of the receptors described here has, to our knowledge, the strongest affinity towards Gly 2– ever reported. Abstract : Receptor design for Gly 2– is not straightforward and small structural changes cause large changes in binding strength. Herein, this conclusion is demonstrated in an experimental study of binding Gly 2– by neutral multidentate receptors based on hydrogen‐bond donor ability through indolocarbazole, urea or carbazole fragments.