Separation of lanthanides and actinides using magnetic silica particles bearing covalently attached tetra-CMPO-calix[4]arenes
作者:Volker Böhmer、Jean-François Dozol、Cordula Grüttner、Karine Liger、Susan E. Matthews、Sandra Rudershausen、Mohamed Saadioui、Pingshan Wang
DOI:10.1039/b405602g
日期:——
Calix[4]arene tetraethers in the cone conformation bearing four –NH–CO–CH2–P(O)Ph2
(= CMPO) residues on their wide rim and one, two or four ω-amino alkyl residues of various lengths at the narrow rim were synthesized. Reaction with dichlorotriazinyl (DCT) functionalized magnetic particles led to complete coverage of the available surface by covalently linked CMPO-calix[4]arenes in all cases. Magnetically assisted removal of Eu(III) and Am(III) from acidic solutions was distinctly more efficient with these particles in comparison to analogous particles bearing the same amount of analogous single-chain CMPO-functions. The best result, an increase of the extraction efficiency by a factor of 140–160, was obtained for attachment via two propyl spacers. The selectivity Am/Eu was in the range of 1.9–2.8. No decrease of the extraction ability was observed, when the particles were repeatedly used, after simple back extraction with water.
1,3-Alternate calix[4]arenes, selectively functionalized by amino groups
作者:Crenguta Danila、Michael Bolte、Volker Böhmer
DOI:10.1039/b414173c
日期:——
synthesize calix[4]arenes which are fixed in the 1,3-alternate conformation and substituted selectively by amino groups. These derivatives are useful starting materials for the attachment of various groups via amide bonds, as demonstrated by several examples, but may be converted also to ureas, imides or azomethines. Four amino groups may be attached to the narrow rim via(several) methylene groups as spacer