Abstract
Control over the conformational flexibility of p-sulfonatocalix[6]-arene in the solid state is possible in the presence of varied stoichiometric amounts of [18]crown-6 and selected lanthanide(III) chlorides. Complexes 1 and 2 have the calixarene in the elusive "up-up" double cone conformation, whilst complex 3 has the calixarene in the centrosymmetric "up-down" double partial cone conformation, whereby it acts as a divergent receptor. Complex 1 has a double "molecular capsule" arrangement which is composed of two p-sulfonatocalix[6]arenes shrouding two [18]crown-6 molecules, also with both coordinated and homoleptic aquated lanthanide ions around the hydrophilic sulfonate rims of the calixarenes. Complex 2 has a "ferris wheel" arrangement with one lanthanide metal centre coordinated to a sulfonate group and another coordinated to the crown ether whilst tethered to a sulfonate group of the calixarene. Complex 3 forms from a solution with large excess of [18]crown-6, and possesses a crown ether molecule in each of the partial cones and has homoleptic aquated lanthanide ions involved in a complicated hydrogen-bonding regime within the extended structure.
Original language | English |
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Pages (from-to) | 2834-2839 |
Number of pages | 6 |
Journal | Chemistry - A European Journal |
Volume | 9 |
Issue number | 12 |
DOIs | |
Publication status | Published - 16 Jun 2003 |
Externally published | Yes |
Keywords
- Calixarenes
- Crown compounds
- Host-guest systems
- Self-assembly
- Supramolecular chemistry