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RESEARCH PRODUCT

Reversible Dimerization of Tetraureas Derived from Calix[4]Arenes

Miquel PonsVolker BöhmerErich F. PaulusO. Mogck

subject

CrystallographyCone conformationchemistry.chemical_compoundChloroformSolvent moleculeChemistryHydrogen bondStereochemistryUreaBenzeneSingle crystalTwo-dimensional nuclear magnetic resonance spectroscopy

description

Calix[4]arene derivatives, substituted at the wider rim by four urea functions are easily available in great variety. In apolar solvents like benzene or chloroform they dimerize via NH…O=C hydrogen bonds encapsulating a single solvent molecule as guest. The exclusive formation of dimers has been proved in solution by NMR, while their shape has been characterized by single crystal X-ray analysis. The kinetic stability and the rate of the guest exchange have been studied by NOESY experiments using a derivative with lower symmetry.

yearjournalcountryeditionlanguage
1999-01-01
https://doi.org/10.1007/978-94-011-4615-9_4