Metallomicellar Complex of 1-Hexadecyl-4-aza-1-azoniabicyclo-[2.2.2]octane Bromide with Copper Dibromide for Solubilization of Nitrofurantoin

Associates of amphiphilic 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide–copper dibromide complex solubilize nitrofurantoin (furadonin). The solubilizing capacity of premicellar aggregates with respect to nitrofurantoin is 15 times higher than that of micelles and is considerably higher (by a factor of 5–16) than the solubilizing effect of micellar solutions of the complex, ligand, and conventional cationic surfactants with respect to Orange OT.     

Amphiphilic Compounds Containing a Carbamate Fragment: Synthesis,Aggregation, and Solubilizing Effect

A new cationic surfactant containing a butylcarbamate fragment as the head group and hexadecyl radical as hydrophobic component has been synthesized and characterized. Its aggregation paremeters have been determined by tensiometry, conductometry, and dynamic light scattering, and its solubilizing capacity for naphthalene and anthracene has been estimated.     

Complexes of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with transition metal nitrates. Micelle-forming,solubilizing, and adsorption properties

Amphiphilic complexes of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide (D-16) with nitrates of transition metals (La³⁺, Cu²⁺, Ni²⁺, and Co²⁺) have been synthesized and characterized. Absorption spectrophotometry in the UV, visible, and IR regions, as well as ¹Н NMR spectroscopy, have been employed to study their spectral properties in water and organic media. Adsorption properties and micelleforming and solubilizing abilities of the amphiphilic complexes have been investigated in aqueous solutions by the methods of tensiometry and conductometry, as well as by solubilization of a water-insoluble dye (Orange OT). The values of the critical micelle concentration, adsorption parameters at a water/air interface, and solubilization capacity S of complex micelles have been determined. It has been shown that the most pronounced decrease in the critical micelle concentration (as large as two to three times) and differences in the adsorption characteristics and the S values as compared with those of ligand D-16 are observed for complexes of copper and lanthanum. The S values for these complexes are 1.3?2.5 and 3?6.5 times higher than those for D-16 and cetyltrimethylammonium bromide, respectively.     

Supramolecular Systems Based on Novel Mono‐ and Dicationic Pyrimidinic Amphiphiles and Oligonucleotides: A Self‐Organization and Complexation Study

Novel mono‐ and dicationic pyrimidinic surfactants are synthesized and their aggregation behavior is studied by methods of tensiometry and nuclear magnetic resonance (NMR) self‐diffusion. To estimate their potentiality as gene delivery agents, the complexation with oligonucleotides (ONus) is explored by dynamic light scattering (DLS) and zeta‐potential titration methods and ethidium bromide exclusion experiments. Bola‐type pyrimidinic amphiphile (BPM) demonstrates rather a weak affinity to ONus. Although it induces mixed associations with ONus, only slight charge compensation changes occur at a large excess of bola, with no recharging reached. Similarly, the ethydium bromide exclusion study reveals a slow increase in the binding capacity toward an ONu with an increment in BPM concentration. The monocationic pyrimidinic surfactant (MPM) and its gemini analogue (GPM‐1) are ranked as intermediates in both their aggregative activity and complexing properties toward ONus. They both form mixed associates with ONus well below the critical micelle concentrations (cmcs) of 2 and 15 mM respectively. However, GPM‐1 has a much lower isoelectric point at the molar ratio surfactant/ONu r～1 compared to r～3 for MPM. This probably indicates a larger electrostatic contribution to the ONu complexation in the case of GPM‐1. The most hydrophobic pyrimidinic surfactant (GPM‐2), bearing three alkyl tails, demonstrates enhanced aggregative activity and binding capacity toward ONus as compared to former pyrimidinic surfactants. Due to effective aggregative (low cmc of 0.04 mM ) plus binding properties (fraction of bound ONu β=0.76 at r=2.5), GPM‐2 may be ranked as a promising agent for wider biological applications.     

On a class of completely continuous operators in Hilbert spaces

We introduce a class G of completely continuous operators and prove theorems on the spectral structure of these operators. In particular, operators of this class are similar to model operators in de Branges spaces.     

Catalytic activity of supramolecular systems on the basis of alkylated polyethylenimines,cationic surfactats,and calix[4]arenes

By means of the dielcometric titration and the dynamic light scattering, the association in the systems based on the alkylated polyethylenimines, hydroxyalkyl cationic surfactants, and calix[4]arenes in chloroform was studied. By means of the UV spectrophotometry the catalytic effect of the aggregates formed on the phosphorylation of polyethylenimines was established. Catalytic effect of the system depends on the structure of surfactants and calixarenes, and also on the relative content of the solution components.