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RESEARCH PRODUCT
Macrocyclic oligoureas with xanthene and diphenyl ether units
Volker BöhmerDenys MeshcheryakovMichael Boltesubject
Models MolecularXantheneMacrocyclic CompoundsMagnetic Resonance SpectroscopyPolymersHydrogen bondChemistryStereochemistryPhenyl EthersOrganic ChemistryDiphenyl etherIntermolecular forceMolecular ConformationCrystallography X-RayBiochemistryCrystallographychemistry.chemical_compoundXanthenesIntramolecular forceProton NMRMoleculeHistone octamerPhysical and Theoretical Chemistrydescription
Two cyclic oligoureas with 64- and 80-membered rings in which two sets of three or four rigid xanthene (X) units are connected via flexible diphenyl ether (D) units were synthesized by a stepwise fragment condensation. The compounds were characterized by (1)H NMR and ESI mass spectrometry. The structure of the cyclic octamer (XXXDXXXD) was additionally confirmed by single crystal X-ray analysis. The molecule assumes a strongly folded conformation with distorted C(2)-symmetry, stabilized by intramolecular hydrogen bonds. Surprisingly, intermolecular hydrogen bonds between the macrocycles were not observed. (1)H NMR spectra suggest a C(2) symmetrical conformation of the octamer in solution also, while its kinetically stable complex with three chloride ions has no symmetry element at all.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-10-16 | Organic & Biomolecular Chemistry |