0000000000000731
AUTHOR
Jaouad Haddaoui
tert-Butyl-calix[4]arenes Substituted at the Narrow Rim with Cobalt Bis(dicarbollide)(1–) and CMPO Groups – New and Efficient Extractants for Lanthanides and Actinides
Calix[4]arene derivatives bearing two residues A(–) derived from cobalt bis(dicarbollide)(1–) (1) and two CMPO groups B at their narrow rim were synthesized from tBu-calix[4]arene in four steps. The first step involved the preparation of tBu-calix[4]arene diether derivatives with appropriate precursors for amino groups (mostly nitriles 3). These were O-alkylated through ring-opening reactions with the zwitterionic dioxane derivative [(8-O(CH2CH2)2O-1,2-C2B9H10)-(1′,2′-C2B9H11)-3,3′-Co]0 (10) to produce ionic nitrile derivatives 4. Reduction of the nitrile groups with BH3·SMe2 (or deprotection in the case of the corresponding phthalimido or Boc derivatives 8) led to a series of diamines 5a–f…
Tetra-CMPO-derivatives of calix[4]arenes fixed in the 1,3-alternate conformation
Calix[4]arene derivatives fixed in the 1,3-alternate conformation and substituted at one side by four carbamoylmethylphosphine oxide (CMPO) residues were synthesised. Two CMPO groups are directly attached to the wide rim, while the second pair is bound to the narrow rim via a tri- or tetramethylene spacer. Similar compounds, in which two CMPO groups at the wide rim are combined with two picolinamide groups or two ionisable carboxylic groups at the narrow rim, were also prepared. Some of these calixarene derivatives were studied as extractants for lanthanides (La3+, Eu3+, Yb3+) and thorium (Th4+) from acidic solution into methylene chloride. For selected samples, stability constants in metha…
Lanthanide complexation with CMPO and CMPO-calix[4]arenes in solution: spectrophotometric and electrospray mass spectrometric approaches.
The binding of lanthanide(III) cations with organophosphorous ligands like CMPO and related calix[4]arene-based derivatives have been investigated using two experimental methods. The stability constants of the lanthanum, europium and ytterbium complexes were first determined in methanol by UV absorption spectrophotometry in the presence of nitrate or chloride anions. The results showed that the stoichiometry and the stability of the complexes formed depend on the position of the CMPO moieties either on the wide or the narrow rim of the calixarene scaffold, the nature of the medium, the conformational mobility of the ligands. Complexation of lanthanum was also followed by ESI-mass spectromet…