Svetlana E. Solovieva

Cloud point extraction of lanthanide(III) ions via use of Triton X-100 without and with water-soluble calixarenes as added chelating agents

The use of water-soluble calixarenes: p-sulfonato thiacalixarene (ST), tetra-sulfonatomethylated calix[4]resorcinarene (SR), calix[4]resorcinarene phosphonic acid (PhR) as chelating agents in cloud point extraction (CPE) of La(III), Gd(III) and Yb(III) ions using Triton X-100 as non-ionic surfactant is introduced. The data obtained indicate that both complexation ability and structure of calixarenes govern the extraction efficiency of lanthanides. In particular ST and SR, forming 1:1 lanthanide complexes with similar stability in aqueous media, exhibit different extractability when used as chelating agents in CPE. First synthesized PhR was found to be the most efficient chelating agent exhibiting pH-dependent selectivity within La(III), Gd(III) and Yb(III) in CPE.

The synthesis of tetracarbonyl derivatives of thiacalix(4)arene in different conformations and their complexation properties towards alkali metal ions

Abstract The three conformations of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis[(benzoyl)methoxy]-2,8,14,20-tetrathiacalix[4]arene 1 : cone, partial cone and 1,3-alternate, were prepared by the treatment of 5,11,17,23-tetra-tert-butyl-2,8,14,20-tetrathiacalix[4]arene-25,26,27,28-tetraol (TCA) with α-bromo acetophenone in the presence of appropriate alkali carbonate M2CO3 (M=Na, K, Cs) as base catalyst in acetonitrile. Structure of the conformers were established by 1H NMR, 1H–1H COSY, 1D NOE, 2D ROESY and X-ray experiments. The alkali cation binding selectivity of the obtained macrocycles was investigated by the ion-pair extraction method.

Molecular tectonics: control of the dimensionality in tetramercaptothiacalixarenes based coordination networks.

Combinations of tetramercaptotetrathiacalix[4]arene pyridyl-appended positional isomers with HgCl2 lead to the formation of neutral coordination networks with their dimensionality imposed by the position of the N atom on the pyridyl group.

Molecular tectonics: p-H-thiacalix[4]arene pyridyl appended positional isomers as tectons for the formation of 1D and 2D mercury coordination networks

Three p-H-thiacalix[4]arene pyridyl appended coordinating tectons (2-4) in a 1,3-alternate conformation have been prepared and structurally characterised in the solid state. These compounds are positional isomers differing only by the position of the nitrogen atom on the pyridyl ring. Their combinations with HgCl2 lead to the formation of 1- and 2-D neutral mercury coordination networks. Whereas for tecton 2 (ortho isomer) a 2D architecture resulting from the bridging of consecutive tectons by the mononuclear HgCl2 unit is obtained, for tecton 3 (meta isomer) again a 2D network is formed. However, in that case, the interconnection of consecutive organic tectons 3 takes place through a binuclear Hg2Cl4 species. Finally, in the case of tecton 4 (para position), a 1D ribbon type double chain arrangement resulting from the bridging of consecutive tectons by trinuclear Hg3Cl6 units followed by the interconnection of two chains through the fusion of the trinuclear centres into a hexanuclear node is observed.

Molecular tectonics: generation of grid and porous diamondoid coordination networks by calixarene based tectons

Combinations of neutral tetrakis meta-pyridyl appended calix[4]arene derivatives in 1,3-A conformation as tectons 3 (tetrakis-meta-pyridyl-tetrathiacalix[4]arene) and 4 (tetrakis-meta-pyridyltetrathiatetramercaptocalix[4]arene) with MX2, behaving as a neutral metallatecton, lead to the formation of 2- and 3-D neutral coordination networks. In all cases, the metal centre adopts a distorted octahedral geometry with the two anions occupying the two apical positions. For compound 3-CdX2 (X = Cl or Br), 4-CdBr2 and 4-FeCl2 similar porous diamondoid 3D networks, resulting from the tetrakis monodentate behaviour of the organic tectons, are formed. In marked contrast, for 4-CoX2 (X = Cl or Br), only two out of the four pyridyl units take part in the connectivity pattern leading thus to the formation of 2D grid type architectures.

Design of supramolecular biomimetic catalysts of high substrate specificity by noncovalent self-assembly of calix[4]arenes with amphiphilic and polymeric amines.

Supramolecular biomimetic catalysts of high substrate specificity are developed based on amphiphilic oxyethylated calix[4]arene bearing iso-nonyl fragments at the upper rim and hexadeca(ethylene glycol) fragments at lower rim (9CO16), and amines of amphiphilic or polymeric nature. Two critical concentrations determined by tensiometry and dye solubilization methods are probably reflect the onset of association process and transition from bimodal to monomodal size distribution revealed by the dynamic light scattering method. Amine components used may form aggregates as well, which is mediated by hydrophobic effect due to occurrence of long-chain alkyl tails. The micellar rate effect of the designed systems toward the cleavage of carboxylic acid ester is shown to be contributed by the formation of mixed aggregates with the reactive functional groups, as well as by the pKa shift of the amine and the character of the distribution of reagents in functional micelles. In the case of long-chain primary amines, an inversion of micellar rate effect (catalysis to inhibition) occurs upon transferring from the less hydrophobic substrate, p-nitrophenyl acetate, to the more hydrophobic analogs, p-nitrophenyl laurate and p-nitrophenyl caprinate. The opposite effect (inhibition of the reaction of p-nitrophenyl acetate and the acceleration of the process of hydrophobic analogs) was observed in systems based on polyethyleneimine.

“Clickable” thiacalix[4]arene derivatives bearing polymerizable 1,3-butadiyne fragments: synthesis and incorporation into polydiacetylene vesicles

p-tert-Butylthiacalix[4]arene derivatives in 1,3-alternate stereoisomeric form bearing polymerisable 1,3-butadiyne fragments on the one side and amino/carboxylic groups on another were synthesized using stepwise functionalisation. Calixarene 7 embedded in polydiacetylene nanoparticles showed a selective colorimetric response toward lanthanide ions.

Langmuir monolayers and thin films of amphifilic thiacalix[4]arenes. Properties and matrix for the immobilization of cytochrome c.

Formation and properties of Langmuir films of thiacalix[4]arene (TCA) derivatives containing N-donor groups on the lower rim (Y═O(CH2)3CN; OCH2CN; NH2; OCH2ArCN-p) in 1,3-alternate conformation on aqueous subphase and solid substrates have been studied. Only tetra-cyanopropoxy-p-tert-butylthiacalix[4]arene 1 forms a typical monomolecular layer with perpendicular orientation of the macrocycle relative to the water-air interface that is able to immobilize cytochrome c in the entire range of the surface pressure. Obtained monolayers were transferred by Langmuir-Schaefer technique onto quartz, indium-tin oxide (ITO), and silicon. It was demonstrated that protein activity is retained after immobilization on the substrate.

Proton conductivity of calix[n]arene-para-sulfonic acids (n = 4, 8)

High proton conductivity in calix[n]arene-para-sulfonic acid hydrates (n = 4, 8) reaching a value of 10−1 Ohm−1 cm−1 at a relative humidity of 80% was revealed for the first time. This value is close to the record conductivity of solid proton conductors and acid water solutions. The dependence of proton transfer parameters and water quantity in the title compounds dependent on the relative humidity of air was investigated.

Synthesis and Characterization of Thiacalix[4]monocrowns Modified by Thioether Groups on the Lower Rim

Abstract A series of thiacalix[4]monocrowns in 1,3-alternate conformation containing thioalkyl fragments was synthesized by the reaction of corresponding distal thiacalix[4]arene derivatives with oligoethylene glycols using a Mitsunobu protocol. GRAPHICAL ABSTRACT