Christophe Bressot

Nuclear Waste Treatment by Means of Supported Liquid Membranes Containing Calixcrown Compounds

Permeability variation with repeated caesium transport experiments has been chosen to measure the leaching of the supported liquid membrane by the contacting aqueous solutions. This allowed us to characterize the SLM stability. Whereas classical crown ethers such as the widely used 21C7 derivatives were revealed to be poorly efficient and poorly stable in SLMs, crown-6-calix[4]arene compounds in the so-called 1,3-alternate configuration led to very stable (over 50 days), highly selective (concentration factor > 100) and efficient (decontamination factor = 20) SLMs, for the removal of caesium from high salinity and acidity media. These results were achieved by using proper organic diluents and introducing hydrophobic substituents in the frame of the calixarenes.

Crystal and molecular structures of binuclear caesium complexes with 1,3-calix[4]-bis-crown-6 and 1,3-calix[4]-bis-benzo-crown-6

The crystal structures of two binuclear complexes between caesium and 1,3-calix[4]-bis-crowns have been determined. Cs2Bis-benzoC6(NO3)2. 3CHCl3 (1) in whichBis-benzoC6 is 1,3-calix[4]-bis-benzo-crown-6, crystallizes in the orthorhombic system: space groupPca21 a=19.513(10),b=15.382(5),c=23.708(9) Å,V=7116(5) Å3,Z=4. Refinement led to a final conventionalR value of 0.065 for 2321 reflections. The structure of (1) is analogous to those already reported withBis-C6, (in whichBis-C6 is, 1,3-calix[4]-bis-crown-6) and NO3− as a counter-ion. Cs2Bis-C6(NCS)2 (2) crystallizes in the monoclinic system: space, groupC2 a=36.57(2),b=11.47(1),c=13.65(1) Å, β=109.03(5)°.,V=5415(6) Å3,Z=4. Refinement led to a final conventionalR value of 0.063 for 2227 reflections. Compound (2) is made of dimers bridged by a disordered NCS− ion. The crown ether chain conformations are discussed.

1,2-Bis-crown-5-calix[4]arene

The title compound, 13,16,19,22,25,39,42,45,48,51-decaoxahexacyclo[35.15.1.1 11,27 .0 5,52 .0 7,12 .0 26,31 .O 33,38 ]-tetrapentaconta-1 (52),2,4,7(12),8,10,26(31),27,29,33(38),34,36-dodecaene, C 44 H 52 O 10 , is a potent and selective alkali metal carrier. Two half-independent molecules are observed in the solid state and they have the «pinched-cone» conformation of the studied calixarenes

Synthesis, Characterization, and X-Ray Structure of 1,2-Bis-crown-5-calix[4]arene. Modeling of Metal Complexation

1,2-bis-crown-5-calix[4]arene (3) was prepared by reacting calix[4]arene (1) with tetraethylene glycol di-p-toluenesulphonate (2) in the presence of cesium carbonate in 9% yield. The X-ray structure of (3) was determined. Crystal data for C44H52O10 are as follows: monoclinic, space groupP2/c witha=18.006(8) A,b=10.680(4) A,c=22.359(6) A, β=112.93(3)°,V=3958(6) A3,Z=4,Dcalc=1.2 g cm−3, the finalR value is 0.11 for the 1851 observed reflections (I>3σ(I)). The single crystal included two similar but slightly different molecules immobilized in a pinched-cone conformation withC2 symmetry. The two enantiomorphous molecules were analyzed by molecular mechanics using the GenMol program to model the selective alkali-metal complexation.