Multisensor system for determination of polyoxometalates containing vanadium at its different oxidation states

The electronic tongue (ET) multisensor system has been employed for the detection of metal-oxygen cluster anions (polyoxometalates) containing vanadium (IV/V) atoms. Sensitivity of a variety of potentiometric chemical sensors with plasticized polyvinyl chloride and chalcogenide glass membranes was evaluated with respect to vanadyl/vanadate ions, decavanadate and a series of Keggin-type polyoxometalates (POM) such as α-[SiW₁₁V^IVO₄₀]⁶⁻, α-[SiW₁₁V^VO₄₀]⁵⁻, α-[BW₁₁V^IVO₄₀]⁷⁻, α-[BW₁₁V^VO₄₀]⁶⁻, α-[PW₁₁V^IVO₄₀]⁵⁻ and α-[PW_12−nV_n^VO₄₀]⁽³⁺ⁿ⁾⁻ (n = 1, 2, 3). Sensor's responses to vanadium complexes were evaluated in the pH range of 2.4-6.5 and a set of sensors appropriate for detecting a variety of vanadium species was selected. Such sensor array was able to distinguish different vanadium complexes allowing their simultaneous quantification in binary (V(IV)/V(V)) mixtures. The vanillyl alcohol oxidation with α-[SiW₁₁V^VO₄₀]⁵⁻ was monitored using ET to evaluate the capacity of proposed analytic system to detect simultaneously V(IV)/V(V) in POM under dynamic equilibrium. ET was demonstrated to be a promising tool for the discrimination and quantification of vanadium-containing POMs at different oxidation states. In particular, such a system could represent a significant interest for the mechanistic studies of redox reactions with POMs.     

Complexes of Fluorinated β-Diketonates of Neodymium for Nd-Containing Liquid Organic Scintillators

Volatile complexes of fluorinated β-diketonates of neodymium(III) (hexafluoroacetylacetonates with glyme and diglyme and decafluoroacetylacetonate with glyme) were studied for applicability in lowbackground Nd-containing organic liquid scintillators. The complexes were prepared in one step and purified by vacuum sublimation. The composition of complexes was determined by ¹H, ¹⁹F, and ¹³C NMR and IR spectroscopy and confirmed by elemental and functional analysis. It was shown that these adducts are suitable for the design of Nd-containing organic liquid scintillators with neodymium concentration of ~1–2 g/L.     

2,2′-Dipyridyl-6,6′-dicarboxylic acid diamides: Synthesis,complexation and extraction properties

New ligands for complexing of the post-transition metals – diamides of 2,2′-bipyridyl-6,6′-dicarboxylic acid were developed, synthesised and characterised. They were proposed to be effective extractants towards americium. The structures of the amides were studied in solid as well as in solution. The extraction of Am and lanthanides depending on diamide structure, chlorinated cobalt dicarbollide (CCD) – diamide ratio, type of diluent was studied. The optimal conditions for Am/REE separation were determined. The properties of new potentiometric sensors on the base of 2,2′-dipyridyl-6,6′-dicarboxylic acid diamides were studied. The correlation structure vs. properties of ionophores (i.e. extractants), their sensitivity and selectivity in sensor analysis and extraction are discussed.     

Novel oximato-bridged platinum(II) di- and trimer(s): synthetic, structural, and in vitro anticancer activity studies

Novel platinum complexes of trans geometry [PtCl(2){(Z)-R(H)C═NOH}(2)] [R = Me (1), Et (3)] and [PtCl(2){(E)-R(H)C═NOH}{(Z)-R(H)C═NOH}] [R = Me (2), Et (4)] as well as the classic trans-[PtCl(2)(R(2)C═NOH)(2)] [R = Me, Et] were reacted with an equivalent amount of silver acetate in acetone solution at ambient temperature, resulting in formation of unprecedented head-to-tail-oriented oximato-bridged dimers [PtCl{μ-(Z)-R(H)C═NO}{(Z)-R(H)C═NOH}](2) [R = Me (5), Et (7)], [PtCl{μ-(Z)-R(H)C═NO}{(E)-R(H)C═NOH}](2) [R = Me (6), Et (8)], and [PtCl(μ-R(2)C═NO)(R(2)C═NOH)](2) [R = Me (9), Et (10)], correspondingly. The dimeric species feature a unique six-membered diplatinacycle and represent the first example of oxime ligands coordinated to platinum via the oxygen atom. All complexes were characterized by elemental analyses, electrospray ionization mass spectrometry, IR and multinuclear ((1)H, (13)C, and (195)Pt) NMR spectroscopy, as well as X-ray diffraction in the cases of dimers 6 and 9. Furthermore, the crystal and molecular structures of a trimeric oximato-bridged complex 11 comprising three platinum units connected in a chain way were established. The cytotoxicity of both dimers and the respective monomers was comparatively evaluated in three human cancer cell lines: cisplatin-sensitive CH1 cells as well as cisplatin-resistant SW480 and A549 cells, whereupon structure-activity relationships were drawn. Thus, it was found that dimerization results in a substantial (up to 7-fold) improvement of IC(50) values of (aldoxime)Pt(II) compounds, whereas for the analogous complexes featuring ketoxime ligands the reverse trend was observed. Remarkably, the novel dimers yielded no cross-resistance with cisplatin in SW480 cells, exhibiting up to 2-fold enhanced cytotoxicity in comparison with the CH1 cell line and thereby possessing a promising potential to overcome resistance toward platinum anticancer drugs. The latter point was also confirmed by investigating the potency of apoptosis induction in the case of one monomer as well as one dimer; the investigated complexes proved to be strong apoptotic agents which could induce cell death even in the cisplatin-resistant SW480 cell line.     

Comparison of the analytical potential of individual sensors and a multisensor system of the “electronic tongue” type for the example of determination of the perchlorate ion

Analytical results obtained in determining the perchlorate ion in individual and mixed solutions by direct potentiometry with separate chemical sensors and with an “electronic tongue” multisensor system were compared. Various anion-exchange compounds (quaternary ammonium salts and metalloporphyrins) and neutral complexation agents (trifluoroacetylbenzoic acid derivatives) were chosen as membrane-active components for sensors.     

Electronic tongue — An array of non-specific chemical sensors — For analysis of radioactive solutions

A variety of novel sensing materials on the basis of phosphine oxides for solvent polymeric sensors have been developed and studied. It was found that phosphine oxide sensors exhibit good sensitivity to rare earth metal cations, such as La³⁺, Pr³⁺, Nd³⁺, Eu³⁺ and also to Y³⁺. Polymeric sensors can be comprised into electronic tongue sensor arrays that may allow detection of several rare-earth metal ions simultaneously in mixed solutions. Such sensor arrays are highly promising for environmental and industrial sensing, e.g., for analysis of spent nuclear fuel.     

Synthesis,Modification, and Biological Evaluation of a Library of Novel Water-Soluble Thiopyridone-Based Organometallic Complexes and Their Unexpected (Biological) Behavior

A series of 16 dinuclear thiopyridone-based organometallics with excellent water solubility, increased stability and remarkable cytotoxicity were synthesized and characterized. The complexes of this work formed dimeric species featuring a double positive charge in polar protic solvents, accounting for their outstanding solubility in aqueous solution. Most of them displayed higher antiproliferative activity than their parental thiomaltol complex, with unexpected cytotoxicity trends depending on the employed metal center, ligand modification, and cell line. Insights into their behavior in biological systems were gathered by means of amino-acid interaction studies, cytotoxicity tests in 3D spheroid models, laser ablation, cellular accumulation measurements, as well as cell cycle experiments.     

Analysis of tea samples with a multisensor system and capillary electrophoresis

Potential of an “electronic tongue” multisensor system in identification of various tea samples and in quantitative analysis of separate tea components was studied. As a reference method for quantitative analysis of antioxidants of the polyphenolic type served micellar electrokinetic chromatography with a UV detector. The contents of epicatechin gallate, epigallocatechin gallate, epicatechin, epigallocatechin, gallic acid, gallocatechin gallate, and caffeine alkaloid in various tea samples were quantitatively estimated.     

Polymeric sensors for determination of rare-earth metal ions, based on diamides of dipicolinic acid

New polymeric sensors with high sensitivity to cations of transition metals and lanthanides in acid media are suggested. The role of active substances in the polymeric membranes of the sensors is played by diamides of dipicolinic acid with various structures, which are compounds exhibiting a high extraction capacity for various metals.     

UV–Vis spectroscopy with chemometric data treatment: an option for on-line control in nuclear industry

Chemometrics can be very useful for the classical field of UV–Vis determination of metals in aqueous solutions. A conventional approach consisting of using selective bands in a univariate mode is often not applicable to the real-world samples from e.g. hydrometallurgical processes, because of overlapping signals, light scattering on foreign particles, gas bubble formation, etc. And this is where chemometrics can do a good job. This paper overviews certain contributions to the field of multivariate data processing of UV–Vis spectra for seemingly simple case of metal detection in aqueous solutions. Special attention is given to applications in nuclear technology field.