Electrochemical properties of metal complexes of dithio-acid derivatives and their application in extraction polarography

Metal complexes with dithiocarbamic (dtc), xanthic (xan) and dithiophosphoric (dtp) acids give rise to one or more polarographic waves in dimethylformamide and in mixtures of extracting solvents and ethanol. The electrons are found to be transferred stepwise in the case of unfilled d-shell metal complexes. The shift of half-wave potential depends on the ligand, increasing in the order dtp < xan < dtc. In solvents with low solvation power the electrode processes are more reversible. The linear dependence of the limiting current on the chelate concentration has been used for determining the metal in the organic phase without re-extraction. Pb(II), Bi(III) and As(III) have been separated with dtp as extractant, and the concentrations of Co(II), Ni(II) and Zn(II) complexes (simultaneously extracted) have been determined polarographically.     

Polynuclear Cu(II) complexes with hyperbranched polyester carboxylates

Polydentate carboxylate platforms based on polyester polyol Boltorn H, containing from 8 to 14 carboxy groups in terminal positions were obtained. A method of synthesis of Cu(II) polynuclear complexes with polyester carboxylates Boltorn H with a degree of substitution of 65 and 90% was developed.     

Formation of a polynuclear cobalt(ii) complex on a polydentate nanoplatform of carboxylated boltorn H20

A method of synthesis of a polynuclear cobalt(II) complex with carboxylated Boltorn H20, a hyperbranched polyol of second generation, has been suggested. The logarithm of stability constant and the composition of the complex species BH20(OC(O)CH₂CH₂COO)₁₂Co₁₂ in a 50% acetone solution have been calculated from the electronic absorption spectra: log?? = 13.7 ± 0.2 and the composition M : L = 12 : 1. The IR spectroscopy and NMR (¹³C and ¹H) point to the coordination of Co(II) ions not only at the surface of the molecule but also near its core.     

Bioaffine methods for determining ajmaline using an amperometric DNA-sensor and an immunoenzyme spectrophotometric test system

Bioaffine methods are developed for determining indole-containing alkaloid ajmaline, which has a cytostatic effect and is used as a cardiac drug. These methods are based on the proposed amperometric DNA-sensor and on immunoenzyme test system with the spectrophotometric indication of the analytical signal. The complex formation between ajmaline and immobilized native DNA allows ajmaline to be efficiently preconcentrated on the biosensor from test solutions. Optimum conditions for preconcentrating ajmaline and those for reactivating the biosensor for its repeated use are found. The time of analysis is 25–30 min, the determination limit for ajmaline is 3.0 × 10⁻¹⁰ M (RSD = 33%). In the test system, the immunological reaction of ajmaline with its antibodies and the enzyme marker, horseradish peroxidase, are used. The determination limit is 4.0 × 10⁻⁹ M (RSD = 33%). Ajmaline is determined by the two methods in model solutions of blood serum and in tablets and solutions for injections.     

Formation of copper nanoparticles with hyperbranched polyesterpolyols as template

New composite copper nanoparticles stabilized by hyperbranched polyesterpolyols of the second, third, and forth generations have been prepared via chemical reduction at different molar ratios of the precursors. The prepared stabilized copper nanoparticles have exhibited fungicide activity against Penicillium funiculosum, Penicillium ochro chloron, Paecilomyces variotii, Aspergillus niger, Aspergillus oryzae, and Aspergillus terreus strains. Copper nanoparticles stabilized by hyperbranched polyesterpolyols of the second and forth generations are hemocompatible.     

Polynuclear copper(II) complexes with polydentate nanoligands on the basis of aminoderivatives of the hyperbranched polyesters

Coordinationally active polydentate nanoplatforms on the basis of amino-modified hyperbranched polyesters containing 7 terminal amino fragments are synthesized. Synthetic procedure is developed and polynuclear Cu(II) complexes with polyesteropolyamines are prepared. Their composition and stability of the complex forms in DMSO-water solutions are evaluated. It is found that all the compounds obtained exhibit biological activity with respect to the induced asparagine proteinase of Candida albicans.     

Electrochemical Properties of Crown-Containing N-(Thio)phosphoryl(thio)ureas and Their Complexes with 3d Transition Metals

The electrochemical behavior of crown-containing N-(thio)phosphoryl(thio)ureas and their complexes with 3d transition metals was studied by dc voltammetry on a graphite electrode in acetone. Crown-containing N-(thio)phosphoryl(thio)ureas are not reduced but are oxidized on solid electrodes in the examined range of potentials; the electrons are transferred via the (thio)urea group. Electrooxidation of macrocyclic Co(II), Ni(II), and Cu(II) complexes probably occurs via formation of M(III) complex species. Electroreduction of these metal complexes involves stepwise electron transfer, with the oxidation state of the metal atom decreasing to 0, followed by dissociation of the electrochemical reaction products.     

Synthesis and properties of hyperbranched polyester polyacrylic acids and their metal complexes

New polydentate ligands based on the hyperbranched third generation polyesters containing terminal acrylic acid fragments were synthesized. The ionization and complexation parameters of new compounds in solution were estimated by spectrophotometry and pH-metric titration followed by experimental data processing using mathematical simulation by the CPESSP program. The procedure for the synthesis was proposed. The polynuclear cobalt(II), nickel(II), and copper(II) complexes with polyester polycarboxylates were synthesized.     

Hyperbranched polyester poly[3-(morpholin-4-yl)propionates] and their copper(II) complexes

Novel polydentate ligands on the basis of second- and third-generation hyperbranched polyesters containing terminal poly[3-(morpholin-4-yl)propionate] groups and their 6 : 1 and 13 : 1 polynuclear copper(II) complexes were synthesized. The degree of functionalization of the polyesters with morpholine increases in going from the second (56%) to third generation (68%). According to IR and electronic spectroscopy data, each coordination entity in the complexes is an isolated paramagnetic center of the formula CuN₂O₂Solv₂ (Solv = H₂O, DMSO).