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Controlling the Conformation and Interplay of p ‐Sulfonatocalix[6]arene as Lanthanide Crown Ether Complexes
Author(s) -
Dalgarno Scott J.,
Hardie Michaele J.,
Makha Mohamed,
Raston Colin L.
Publication year - 2003
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.200304963
Subject(s) - calixarene , lanthanide , homoleptic , chemistry , crown ether , molecule , crystallography , sulfonate , ether , inorganic chemistry , stereochemistry , metal , ion , organic chemistry , sodium
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.