Premium
Molecules with New Topologies Derived from Hydrogen‐Bonded Dimers of Tetraurea Calix[4]arenes
Author(s) -
Bogdan Anca,
Bolte Michael,
Böhmer Volker
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801268
Subject(s) - chemistry , steric effects , residue (chemistry) , molecule , calixarene , olefin metathesis , crystal structure , olefin fiber , stereochemistry , hydrogen bond , metathesis , nuclear magnetic resonance spectroscopy , aryl , polymer chemistry , crystallography , topology (electrical circuits) , organic chemistry , catalysis , polymerization , alkyl , mathematics , combinatorics , polymer
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.