Diclofenac sodium aqueous systems at low concentrations: Interconnection between physicochemical properties and action on hydrobionts.

Diclofenac sodium (DS) is a widely used nonsteroidal anti-inflammatory drug (NSAIDs). NSAIDs are poorly removed during standard wastewater treatment. The consequences of the presence of NSAIDs in rivers and lakes at 10-10 mol/L are not yet established; therefore, ecotoxicologists have focused their efforts on studying the effect of low-concentration NSAIDs on fish and hydrobionts, and also on predicting the potential risks to humans.

Nanoconjugates of a calixresorcinarene derivative with methoxy poly(ethylene glycol) fragments for drug encapsulation.

In order to obtain a non-toxic amphiphilic calixresorcinarene capable to form nanoconjugates for drug encapsulation, tetraundecylcalixresorcinarene functionalized by methoxy poly(ethylene glycol) chains has been synthesized. The macrocycle obtained is characterized by low hemotoxicity. In aqueous solution it forms nanoassociates that are able to encapsulate organic substrates of different hydrophobicity, including drugs (doxorubicin, naproxen, ibuprofen, quercetin).

Closed polymer containers based on phenylboronic esters of resorcinarenes.

Novel polymer nanospheres (p(SRA-B)) were prepared by cross-linking a sulfonated resorcinarene (SRA) with phenylboronic acid. p(SRA-B) shows good stability in water and can be used as a nanocontainer for the pH- and glucose-controlled substrate release. Fluorescent dyes (fluorescein, pyrene and 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt) were successfully loaded into p(SRA-B).

High catalytic activity of palladium nanoparticle clusters supported on a spherical polymer network.

In this communication we report the synthesis of Pd nanoparticle clusters achieved via the assembly of Pd nanoparticles on the surface of a spherical polymer network. The network exhibits flexibility and adapts to the cluster formation. The nanoclusters display high catalytic activity toward p-nitrophenol reduction and the Suzuki-Miyaura coupling reaction.

Tb(III)-doped silica nanoparticles for sensing: effect of interfacial interactions on substrate-induced luminescent response.

The present work introduces the easy modification of the water-in-oil microemulsion procedure aimed at the doping of the Tb(III) complexes within core or shell zones of the silica nanoparticles (SNs), which are designated as "core-shell", "shell", and "core". The dye molecules, chelating ligands, and copper ions were applied as the quenchers of Tb(III)-centered luminescence through dynamic or/and static mechanisms. The binding of the quenchers at the silica/water interface results in the quenching of the Tb(III) complexes within SNs, which, in turn, is greatly dependent on the synthetic procedure.

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.

Controlling the size and morphology of supramolecular assemblies of viologen-resorcin[4]arene cavitands.

A novel class of self-assembling nanoparticles is formed with viologen-resorcin[4]arene cavitands; the association model is strongly controlled by their hydrophobicity. Interestingly, the cavitand assemblies are designed through click chemistry to form self-assembled noncovalently connected aggregates through counterion displacement. The iodide and benzoate ions are utilized as strongly polarizable counterions to induce cavitand self-assembly.

Changes in permittivity and density of molecular liquids under high pressure.

We collected and analyzed the density and permittivity of 57 nonpolar and dipolar molecular liquids at different temperatures (143 sets) and pressures (555 sets). No equation was found that could accurately predict the change to polar liquid permittivity by the change of its density in the range of the pressures and temperatures tested. Consequently, the influence of high hydrostatic pressure and temperature on liquid permittivity may be a more complicated process compared to density changes.

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 energy transfer based fluorescent approach to detect the formation of silica supported phosphatidylcholine and phosphatidylserine containing bilayers.

The work introduces the quenching of silica coated Tb(III) complexes by merocyanine 540 (MC540) and copper ions as a tool to reveal the adsorption of phosphatidylcholine (PC) and phosphatidylserine (PS) at various PS:PC ratio onto silica nanoparticles doped with Tb(III) complex. The binding of MC540 with PC-based bilayers and copper ions with PS-based ones are the basis of their use as organic and inorganic probes to sense PS:PC ratio in silica supported mixed bilayers. The enrichment of mixed bilayers by PS results in the displacement of MC540 anions, while it enhances the binding with copper ions.

Supramolecular design of biocompatible nanocontainers based on amphiphilic derivatives of a natural compound isosteviol.

Two diterpenoid surfactants with ammonium head groups and bromide (S1) or tosylate (S2) counterions have been synthesized. Exploration of these biomimetic species made it possible to demonstrate that even minor structural changes beyond their chemical nature may dramatically affect their solution behavior. While their aggregation thresholds differ inconsiderably, morphological behavior and affinity to lipid bilayer are strongly dependent on the counterion nature.

Crystal violet dye in complexes with amphiphilic anionic calix[4]resorcinarenes: binding by aggregates and individual molecules.

Here, we report on a systematic study of six calix[4]resorcinarene macrocycles bearing eight carboxylic groups on the upper rim and four different lower rim substituents that are either aliphatic (2, 4, and 5) or alkylaromatic (1, 3, and 6). The macrocycles were studied in their individual aqueous solutions and in the presence of triphenylmethane dye crystal violet. It was found that binding of crystal violet with aggregated macrocycles shields it from the bulk of solution, preventing its discoloration under basic conditions and electrochemical reduction on the glassy carbon electrode.

Tunable biomimetic systems based on a novel amphiphilic pyrimidinophane and a helper nonionic surfactant.

Tunable nanosystems based on a novel water insoluble pyrimidinic amphiphile are designed. pH dependent aggregates composed of protonated pyrimidinophane 1 are formed at pH<4, which undergo reversible transition to precipitate at neutral and basic conditions. The approach assuming the application of a helper nonionic surfactant Triton-X-100 (TX-100) is used in this work.

Novel biomimetic systems based on amphiphilic compounds with a diterpenoid fragment: role of counterions in self-assembly.

Novel biomimetic systems are designed based on cationic surfactants composed of an isosteviol moiety and different counterions, namely bromide (S1) and tosylate (S2). The counterion structure is shown to play a crucial role in the surfactant association. A number of methods used provide evidence that only one type of aggregate, i.

The discrimination between phospholipids of diverse structure and phosphacoumarins of various hydrophobicity through fluorescent response of Tb-doped silica nanoparticles decorated by cationic surfactant.

The work represents colloids of silica nanoparticles displaying fluorescent response on biorelevant compounds exemplified by phosphacoumarins and phospholipids. The luminescent properties of the colloids arise from Tb(III) complexes doped into silica nanoparticles (SNs). The noncovalent decoration of SNs by dicationic surfactant with further interfacial binding of dye anions enables to develop colloids programmed to display a substrate induced fluorescent response.

Guest controlled aggregation of amphiphilic sulfonatomethylated calix[4]resorcinarenes in aqueous solutions.

Supramolecular nanoaggregates formed through the association of amphiphilic sulfonatomethylated calix[4]resorcinarenes with different substituents on the lower rim (methyl, pentyl, heptyl) and number of aromatic, aliphatic, and cationic guests differing in their shapes and sizes were investigated in aqueous solution by various NMR techniques ((1)H, 2D NOESY, FT-PGSE). It was shown that slight variations of the alkyl chain length on the lower rim of calixresorcinarenes dramatically change their aggregation behavior. Unlike the other calixresorcinarenes studied, the "head-to-tail" packing mode is observed for calixresorcinarene with pentyl moieties on the lower rim, which is unusual for amphiphilic calixarene aggregates.

The interfacial interactions of Tb-doped silica nanoparticles with surfactants and phospholipids revealed through the fluorescent response.

The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence enables to sense the aggregation of cationic and anionic surfactants near the silica surface of Tb-doped silica nanoparticles (SN) in aqueous solutions. The Tb-centered luminescence of non-decorated SNs is diminished by the inner filter effect of both dyes. The decoration of the silica surface by cationic surfactants induces the quenching through the energy transfer between silica coated Tb(III) complexes and dye anions inserted into surfactant aggregates.

Self-assembling systems based on amphiphilic alkyltriphenylphosphonium bromides: elucidation of the role of head group.

A systematic study of the aggregation behavior of alkyltriphenylphosphonium bromides (TPPB-n; n=8, 10, 12, 14, 16, 18; here n is the number of carbon atoms in alkyl groups) in aqueous solutions has been carried out and compared with trimethyl ammonium bromides (TMAB-n). Critical micelle concentrations (cmcs) of TPPB-n and TMAB-n decrease with the number of carbon atoms with the slope parameter of ca.0.

Cascade and commutative self-assembles of nanoscale three-component systems controlled by the conformation of thiacalix[4]arene.

In this work, the formation of two- and three-component supramolecular systems based on cone, partial cone, 1,3-alternate stereoisomers of heteroditopic "hosts": p-tert-butylthiacalix[4]arene containing 4-amidopyridine fragments with silver(I) cations and dicarboxylic acids in liquid and solid phases were studied by UV spectroscopy, dynamic light scattering, and atomic force microscopy methods. It has been shown that these macrocycles are coreceptors, capable of simultaneously binding silver(I) cations, dicarboxylic acids (oxalic, malonic, succinic, maleic, fumaric acids), and hydroxyl acids (glycol, tartaric acids). For the first time, by the dynamic light scattering method, it has been shown that the conformation of p-tert-butyl thiacalix[4]arenes significantly affects the type of three-component system formed: cone is characterized by the formation of cascade systems; for partial cone, intermediate systems; and for the 1,3-alternate stereoisomers, three types of three-component systems (cascade, intermediate, and commutative) were observed.

Novel self-assembling system based on resorcinarene and cationic surfactant.

Mixed association of calix[4]resorcinarene with ethyl sulfonate groups on the lower rim and dimethylaminomethyl groups on the upper rim (CR) and cationic surfactant 4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide (DABCO-16) is studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy at fixed CR concentration and varied surfactant concentration.

p-tert-Butyl thiacalix[4]arenes functionalized at the lower rim by amide, hydroxyl and ester groups as anion receptors.

New p-tert-butyl thiacalix[4]arenes differently substituted at the lower rim with amide, hydroxyl and ester groups were synthesized. Binding properties of the compounds toward some tetrabutylammonium salts n-Bu(4)NX (X = F(-), Cl(-), Br(-), I(-), CH(3)CO(2)(-), H(2)PO(4)(-), NO(3)(-)) were studied by UV spectroscopy. It was found that the stoichiometry of the complexes, generally, is 1 : 1, and the association constants are in the range of 10(3)-10(5) M(-1).

Novel bolaamphiphilic pyrimidinophane as building block for design of nanosized supramolecular systems with concentration-dependent structural behavior.

A new macrocyclic bolaamphiphile with thiocytosine fragments in the molecule (B1) has been synthesized and advanced as perspective platform for the design of soft supramolecular systems. Strong concentration-dependent structural behavior is observed in the water-DMF (20% vol) solution of B1 as revealed by methods of tensiometry, conductometry, dynamic light scattering, and atomic force microscopy. Two breakpoints are observed in the surface tension isotherms.

Temperature induced phase separation of luminescent silica nanoparticles in Triton X-100 solutions.

The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied in Triton X-100 (TX-100) solutions at various concentration conditions by fluorimetry, dynamic light scattering, electrophoresis and transmission electron microscopy methods. The temperature responsive behavior of nanoparticles is observed at definite concentration of TX-100, where the aggregation of TX-100 at the silica/water interface is evident from the increased size of the silica nanoparticles. The reversible dehydration of TX-100 aggregates at the silica/water interface should be assumed as the main reason of the temperature induced phase separation of silica nanoparticles.

Investigation of tetramethylenesulfonated calix[4]resorcinarene interactions with azo dyes in aqueous solution.

The interaction of a macrocycle's aggregates with a guest molecule has special interest due to the double role, both of macrocycle cavity and self-associates, in the binding of the guests. Here, we report on the interactions of nonaggregated methyl-substituted (SCA1) and aggregated penthyl-substituted (SCA2) tetramethylenesulfonated calix[4]resorcinarenes with pH indicators methyl yellow (MY) and methyl orange (MO) in aqueous solutions. It was found that the pH of aqueous solutions of SCA1 and SCA2 depends on their concentration; besides, variation of the concentration of SCA1 and SCA2 results in a shift of the absorption maxima and of pH-sensitive azo dyes.

IR and NMR spectra, intramolecular hydrogen bonding and conformations of para-tert-butyl-aminothiacalix[4]arene in solid state and chloroform solution.

It is demonstrated that dissolution of aminothiacalix[4]arene in chloroform results in transformation of 1,3-alternate conformation, adopted in single-crystal and bulk polycrystalline solids, to the pinched-cone form. This conformer is stabilised by the intramolecular hydrogen bonds of two distal amino-groups acting as H-donors with another two amino moieties that appear as H-acceptors. The H-bonds cause quite small (ca.