Molecules with New Topologies Derived from Hydrogen-Bonded Dimers of Tetraurea Calix[4]arenes

✍ Scribed by Anca Bogdan; Michael Bolte; Volker Böhmer

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 450 KB
• Volume: 14
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200801268

✦ Synopsis

Abstract

Tetraurea calix[4]arenes 2 have been synthesized in which two adjacent aryl urea residues are connected to a loop by an aliphatic chain ‐O‐(CH~2~)~n~‐O‐. The remaining urea residues have a bulky 3,5‐di‐tert‐butylphenyl residue and an ω‐alkenyloxyphenyl residue. Since this bulky residue cannot pass through the loop, only one homodimer (2⋅2) is formed in apolar solvents, for steric reasons, in which the two alkenyl residues penetrate the two macrocyclic loops. Covalent connection of these alkenyl groups by olefin metathesis followed by hydrogenation creates compounds 3, which consist of molecules with hitherto unknown topology. Their molecular structure was confirmed by ^1^H NMR spectroscopy and ESIMS, and for one example by single‐crystal X‐ray analysis.