Herges, Rainer and Dikmans, Anton and Jana, Umasish and Koehler, Felix and Jones, Peter G. and Dix, Ina and Fricke, Tom and Koenig, Burkhard (2002) Design of a neutral macrocyclic ionophore: Synthesis and binding properties for nitrate and bromide anions. EUROPEAN JOURNAL OF ORGANIC CHEMISTRY (17). pp. 3004-3014. ISSN 1434-193X, 1099-0690
Full text not available from this repository. (Request a copy)Abstract
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 = 0) 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 = 0) are substantial for a neutral ionophore with defined binding sites in pure DMSO solution. Bromide ions, which have a similar ion radius, are bound with an even higher afinity Chloride is obviously too small, and iodine too large, to form 1:1 complexes. The binding motif of 8 (X = 0) was compared with related molecules of similar structure, such is 8 (X = S) and 19, As predicted from calculations, the. small structural variations give rise to a complete loss of nitrate and bromide ion binding ability in DMSO, This sensitivity to geometrical changes, and the, affinity of 8 (X = 0) to nitrate and bromide ions, which ire poor hydrogen bond acceptants, confirm the predicted complementarity of ionophore binding site and anion geometry. According to DFT and MD calculations, the higher affinity of 8 (X = 0) to bromide than to nitrate is mainly due to the greater flexibility of the bromide complex and thus to its higher entropy. (C) Wiley-VCH Verlag GmbH, 69451 Veinheim, Germany, 2002.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | HYDROGEN-BONDING RECEPTORS; RECOGNITION; COMPLEXATION; MOLECULES; CONTINUUM; SENSORS; ACID; UREA; anions; receptors; density functional calculations; environmental chemistry; macrocycles |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Lehrstuhl Prof. Dr. Burkhard König |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 01 Sep 2021 10:34 |
| Last Modified: | 01 Sep 2021 10:34 |
| URI: | https://pred.uni-regensburg.de/id/eprint/39902 |
Actions (login required)
 |
View Item |
