Design of a Neutral Macrocyclic Ionophore: Synthesis and Binding Properties for Nitrate and Bromide Anions
✍ Scribed by Rainer Herges; Anton Dikmans; Umasish Jana; Felix Köhler; Peter G. Jones; Ina Dix; Tom Fricke; Burkhard König
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 281 KB
- Volume
- 2002
- Category
- Article
- ISSN
- 1434-193X
No coin nor oath required. For personal study only.
✦ Synopsis
A macrocyclic neutral ionophore 8 (X = O) capable of binding weakly coordinating anions such as nitrate and bromide in DMSO solution has been designed by a stepwise, deductive approach. The optimum geometrical arrangement of the hydrogen bond donor sites in the target ionophore was determined by DFT calculations. From these data, a suitable macrocyclic molecular framework was constructed. The 24-membered macrocyclic ionophore was synthesized by standard macrocyclization methods. NMR titrations revealed molecular complexes with defined 1:1 stoichiometries in DMSO for 8 (X = O) with nitrate, hydrogensulfate, acetate, cyanide, iodide, and bromide ions, while dihydrogenphosphate, sulfate, and chloride ions yielded aggregates of higher stoichiometry. The nitrate binding constants of 8 (X = O) are substantial for a neutral ionophore with defined binding sites in pure DMSO solution. Bromide ions, which have a similar ion radius, are