CMPO-calix arene

Wide-rim tetra(CMPO) calix[4]arenes present good extraction abilities and also rather good selectivities at high acidity. But, the stability toward hydrolysis is not very good. N-methylated compounds exhibit low extraction efficiency, but higher stability toward hydrolysis when they are in contact with strong nitric acid (3 M). 

Tetra(CMPO) cavitands present nearly the same extraction properties as wide-rim tetra CMPO calix[4]arenes, but a slightly lower selectivity. 

Narrow-rim hexa(CMPO) calix[6]arenes are very promising, having very high distribution ratios, especially at high acidities, and also remarkable selectivities. 

Extraction by Wide-Rim CMPO Calix[4]arenes and Oligomers... 

Stability Constants (log Pv) of Europium Complexes with Wide-Rim CMPO Calix[4]arenes and Linear Counterparts in Methanol (/= 0.05 M NaN03)... 

All the complexes metal wide-rim CMPO calix[4]arene studied by crystallographic analysis have the 2 1 Micalix stoichiometry. Cations are complexed by two bidentate CMPO, which keep them apart from the cavity of the calix[4]arene. Thus, these complexes are not real inclusion complexes (Figure 4.8). 

The wide-rim CMPO calix[4]arenes are the most efficient compounds for the extraction of trivalent actinides and lanthanides. They are also the compounds that display the highest selectivity along the lanthanide series, provided that phosphorus atoms are linked to phenyl groups. They also display a higher selectivity than the calixarene-bearing diphosphine oxide, where the phosphorus atom is linked to phenyl units CPo21.176- ... 

Since in the case of p-H calixarenes, a precipitate occurred at the water/organic interphase, extraction tests were carried at a concentration of 10" M for these compounds. The presence of tert-butyl or benzyloxy at the wide rim helps to solubilize the complexes. The distribution ratios are compared to wide-rim CPw3 and narrow-rim CPn3 (Table 4.34).179 For all CMPO-calix[6,8]arenes, distribution ratios of the two cations studied (Eu and Am) increase with increasing HN03 concentration, in agreement with what is observed with tetramers bearing CMPO residues... 

Distribution Ratios and Selectivity SAm/Eu for Am and Eu From Aqueous Solutions into a NPHE Solution of CMPO-calix[6,8]Arenes (10 3 M)... 

In collaboration with the Mainz group, Parma University workers synthesized CMPO-calix[6]arenes CP64 and CP65, bearing three CMPO binding sites onto the narrow and wide rim, respectively. CP65 and to a lesser extent CP64 display relatively low distribution ratios and a selectivity SAm/Eu lesser than 2.5.18... 

Magnetic Particles Bearing CMPO Calix[4]arenes... 

A calix[4]arene substituted at the upper-rim VIg was synthesized from calix[4]arene-0-tetra pentyloxy derivative conformationally fixed at the low rim by alkyl chains and substituted with two nitro groups and two phenolic hydroxyls at the wide rim in the opposite positions at the platform. After 0-alkylation with two equivalents of the CD-dioxane derivative and on reduction of the nitro fnnctions to the ammonium group, two CMPO functions were introduced by reaction with the active ester ae-1 (see Figure 19.3, VIg) (Griiner et al, unpublished results). However, in contrast to organic upper-rim CMPO calix[4]arenes (Schmidt, 2003), a lower separation efficiency was observed for this compound with respect to the low-rim series. This can be possibly explained by a different complexation mode. No An +/Ln2+ selectivity was observed, similarly as for the low-rim series. 

Schmidt, C., Saadioui, M., Bohmer, V. et al. 2003. Modification of calix[4]arenes with CMPO-functions at the wide rim. Synthesis, solution behavior, and separation of actinides from lanthanides. Org. Biomol. Chem. 1 4089 4096. 

Sansone, F., Fontanella, M., Casnati, A., Ungaro, R., Bohmer, V., Saadioui, M., Liger, K., Dozol, J.F. 2006. CMPO-substituted calix[6]- and calix[8]arene extractants for the separation of An3+/Ln3+ from radioactive waste. Tetrahedron 62(29) 6749-6753. 

In the second project, gathering nine teams from six EC countries, more than 150 new extractants were prepared and studied, and the target was reached for the decategorization of waste. Dialkoxy calix[4]arene-crown-6 for cesium, octaamide calix[8] arenes, and CMPO-like calixarenes for actinides display much higher complexing and extracting abilities than other classical extractants, crown ethers, or dicarbollides proposed and sometimes used for this purpose. 

Extraction by Wide-rim N-methylated CMPO Calixarenes Two calix[4]arene tetraethers (pentoxy CPwl7 and tetradecyloxy CPwl8) bearing four -N(Me)-C0-CH2-P(0)Ph2 residues on their wide-rim were synthesized for the first time.170 Their ability to extract lanthanides and actinides from an acidic aqueous... 

Under the same conditions, in contrast to what is observed for calix[4]arene-bearing CMPO moieties, with CPil2, distribution ratios of lanthanides increase from the lightest lanthanide, lanthanum, to europium. Americium can be easily separated from the lightest lanthanides (separation factor DAm/La > 20, DAm/Ce =15, /lAlll,Nd = 10, UAi /si = 7.5, DAm/Eu = 6), which are the most abundant lanthanides in fission-product solution. Cavitands bearing picolinamide (Cv5) or thiopicolin-amide (Cv6) residues seems much less selective than their calixarene counterparts, giving SAm/Eu < 2.18... 

Bohmer et al. also synthesized calixarenes bearing one or more CMPO moieties and another functionality (malonamide or carboxylate). These calixarenes display lower extracting ability than CPw3, and contrary to expectations, these functions do not lead to a new order of selectivity. Calix[4]arenes bearing one or two adjacent malonic acid groups (NH-C(0)-CH2-C00H) adjacent to CMPO functions at the wide rim were unstable and decomposed during the complex-ation studies. 

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