Sulphur-rich functionalized calix[4]arenes for selective complexation of Hg2+ over Cu2+, Zn2+ and Cd2+

[Abstract] The syntheses of two new ligands based on a calix[4]arene scaffold in the cone conformation functionalized on the phenolic positions 1 and 3 by diethylthiophosphonates (L1) or tetra(tri)thioethyleneglycol (L2) crowns are described. Together with ligand L3, the parent calix[4]arene substituted by a penta(tetra)thioethyleneglycol crown, the spectroscopic properties of the ligands were determined by means of UV-Vis absorption spectroscopy and steady-state and time-resolved fluorescence spectroscopy, showing that the ligands display modest but non-negligible intrinsic fluorescence properties (ϕfluo = 0.023; 0.026 and 0.029 for L1, L2 and L3 in CH2Cl2, respectively). The X-ray crystal structures of ligand L1, and of its synthetic precursor were determined and analyzed for their capacity to accommodate the incoming cationic species. The ligands were further investigated for their complexation properties of divalent cations such as Cu2+, Zn2+, Hg2+ and Cd2+ (under their nitrate salts) in 1:1 CH3CN/CH2Cl2 solutions (I = 0.01 M Et4NNO3, T = 25.0(2) °C), in which the additions of cations were monitored by absorption and steady-state fluorescence spectrophotometries. The stoichiometries of the corresponding complexes were assessed by ESI-MS, while insights into the structures of the complexes in solution were obtained with density functional theory (DFT) calculations. The influence of the sulphur and phenol coordinating moieties was addressed to show that the thiocrown compounds L2 and L3 displayed a marked affinity towards the soft mercuric cation (ΔlogK ≥ 2), with no particular size selectivity effect, whereas ligand L1 can accommodate both the thio and phenol units to coordinate with Cu(II). Altogether, these results point to the use of L3 as a selective fluoroionophore for detection of Hg2+

Conception d'immunogènes métalliques en vue de la détection du césium par immunoanalyse (Synthèse et caractérisation)

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Solvent Extraction of Some Univalent Cations into Nitrobenzene by Using Cesium Dicarbollylcobaltate and Four Bis(crown-6) Ether Derivatives of Calix[4]arene

International audienceOn the basis of extraction experiments and -activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+CsL+(nb) ML+(nb)+Cs+(aq) occurring in the two-phase water-nitrobenzene system (M+=K+, Rb+, Ag+, Tl+; L=bis(crown-6) ether derivatives of calix[4]arene, where aq=aqueous phase and nb=nitrobenzene phase) were evaluated. Moreover, the stability constants of the proven ML+ complexes in water-saturated nitrobenzene were calculated and are discussed. [GRAPHICS]

Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilizing uranyl cations.

International audienceWith the aim of developing supports for uranyl cations immobilization, new 1,3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxabutyrate as the anchoring arm were synthesized in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilization of uranyl cations was obtained

Calix[4]arene-(1,2-phenylene-crown-6,crown-6) as an extraordinarily effective macrocyclic receptor for the univalent silver cation

<p>On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ag⁺(aq) + <b>1·</b>Cs⁺(nb) <b>1·</b>Ag⁺(nb) + Cs⁺ (aq) occurring in the two-phase water–nitrobenzene system (<b>1</b> = calix[4]arene-(1,2-phenylene-crown-6,crown-6); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log <i>K</i>_ex(Ag⁺, <b>1·</b>Cs⁺) = −1.3 ± 0.1. Further, the very high stability constant of the <b>1·</b>Ag⁺ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β_nb(<b>1·</b>Ag ⁺) = 9.3 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structures A and B of this cationic complex species, which are obviously in a dynamic equilibrium, were derived.</p> <p></p