Tetra-urea calix[4]arenes 1,3-bridged at the narrow rim.

The synthesis of special tetra-urea calix[4]arene derivatives is described. Two propyl ether groups in 1,3-position and a 5-iodo-isophthalamide bridge connecting two aminopropylether residues in 2,4-position at the narrow rim keep the molecule fixed in the cone conformation. The aryl urea residues are substituted by decyloxy groups in p-position to increase the solubility in apolar solvents, while the iodo substituent allows further functionalization.

Tetraurea calix[4]arenes with sulfur functions: synthesis, dimerization to capsules, and self-assembly on gold.

Various calix[4]arene derivatives, fixed in the cone conformation by decylether groups and functionalized at their wide rim by urea residues, were synthesized. In two compounds (,) sulfur functions were attached to the urea groups via different spacers in order to allow binding to metal surfaces. While they exist as single molecules in polar solvents, tetraurea calix[4]arenes of this type () combine to form dimeric capsules in aprotic, apolar solvents.

Supramolecular structures formed by calix[8]arene derivatives.

Octamethoxy calix[8]arenes substituted in the para position by amide, urea, and imide functions were synthesized from the octamethyl ether of tert-butylcalix[8]arene by ipso nitration, reduction, and acylation. Scanning force microscopy of spin coated samples on graphite suggests that these derivatives self-organize into tubular nanorods via hydrogen bonds between p-amide functions. A single-crystal X-ray structure reveals a centrosymmetric conformation for the octanitro derivative.