Radiation-modified wool for adsorption of redox metals and potentially for nanoparticles

Electron beam irradiated sheep wool with absorbed radiation doses ranging from 0 to 165 kGy showed good adsorption properties toward copper cations. The Cu(ii) being Lewis acid generated several types of complex salts based on carboxylates or cysteinates with ligands available in keratin. Under these conditions, cross-links were formed between the keratin chains. Experimental data obtained from Cu(ii) adsorption using the concentration of 800-5,000 mg/L were tested for fitting to 10 isotherm models. Various compositions and architectures of the Cu(ii)-complexes were specified to be responsible for different isotherm model fittings. The copper cation showed adherence to Langmuir, Flory-Huggins, and partially Redlich-Peterson models. The latter clearly distinguished the native wool from the modified ones. Another aim is to investigate the conditions for the adsorption of anti-microbial nanoparticles in addition to the redox-active metals on radiation-modified wool taking into account that the diffusion of nanoparticles into the modified wool is governed by electrostatic interactions. © 2020 Mária Porubská et al., published by De Gruyter 2020.Research and Developments Support Agency [APVV-15-0079

Testing of electron beam irradiated sheep wool for adsorption of Cr(III) and Co(II) of higher concentrations

Electron beam irradiated sheep wool dosed (0–410) kGy showing good adsorption properties was tested for Cr(III) and Co(II) of higher concentrations. Fitting to ten isotherm models was examined as follows: Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Flory-Huggins, Halsey, Harkins-Jura, Jovanovic, Elovich and Redlich-Peterson. Both cations being Lewis acids generate complex salts, such as carboxylates or cysteinates, with ligands from keratin. Various composition and architecture of the complexes are responsible for different isotherm model fitting. The chromic cation showed adherence to Freundlich, Temkin, Halsey, Harkins-Jura and Jovanovic models for all or almost all dosed samples unlike cobaltous cation matching Langmuir, Flory-Huggins and Redlich-Peterson isotherm models. No model fitted the both examined cations simultaneously. On the contrary, simultaneously non-fitting to all dosed samples was observed for Elovich and partially Dubinin-Radushkevich models. © 2021 The Author(s)Univerzita Palackého v Olomouc

π-π interactions in the supramolecular structure of (4,7-dimethyl- 1,10 phenanthroline)(triphenylphosphine) tetrahydridoborato- copper(I)

Abstract The title compound, [Cu(C 12 H 12 N 2 )(C 18 H 15 P)(BH 4 )], crystallizes with two molecules in the asymmetric unit. Each Cu + ion is pentacoordinated by 4.7-dimethyl-1,10-phenanthroline, triphenylphosphine and tetrahydroborate anions in η 2 -coordination mode. A π-π stacking interaction is observed between the aromatic rings of adjacent 4,7-dimethyl-1,10 phenanthroline ligands

A Switch between Antioxidant and Prooxidant Properties of the Phenolic Compounds Myricetin, Morin, 3′,4′-Dihydroxyflavone, Taxifolin and 4-Hydroxy-Coumarin in the Presence of Copper(II) Ions: A Spectroscopic, Absorption Titration and DNA Damage Study

The beneficial effects of polyphenols, predominantly in the context of oxidative stress-related diseases such as cancer, cardiovascular diseases and neurological conditions including Alzheimer’s and Parkinson’s diseases, have been documented by a number of papers and reviews. The antioxidant/prooxidant properties of phenolic compounds are related mainly to the number and positions of hydroxyl groups and to their redox metal (Cu, Fe) chelating capacity. In this work we studied structurally distinct phenolic molecules such as myricetin, morin, 3′,4′-dihydroxy-flavone, taxifolin and 4-hydroxycoumarin, either alone or as interacting with Cu2+ ions. EPR and UV-Vis spectroscopy confirmed that the effective binding of cupric ions to phenolic compounds requires the presence of the 3-OH and 4-CO groups on the flavonoid C ring and unsaturated C2-C3 bond of the C-ring, which permits through-conjugation with the B-ring. An ABTS assay revealed that radical scavenging activities of phenolic compounds are related to their number of hydroxyl groups, planarity of the molecular skeleton, extent of delocalization and they decrease in the order: myricetin > morin > 3′,4′-dihydroxyflavone ~ 4-hydroxy coumarin > taxifolin. Absorption titrations indicate that copper ions can modulate the DNA binding affinity of flavonoids via the formation of their Cu-chelates. Gel electrophoresis measurements indicated that the protective effect of the phenolic compounds decreases in the order: 3′,4′-dihydroxyflavone > 4-OH coumarin > morin > taxifolin ~ myricetin. This can be explained by the fact that myricetin, taxifolin and morin form stable Cu(II) complexes capable of causing DNA damage via interaction with DNA and ROS formation via the Fenton reaction. Application of ROS scavengers revealed the formation of singlet oxygen, superoxide and hydroxyl radicals and their concerted synergistic effect on the DNA. The overall results suggest that the most pronounced DNA damage has been observed for flavonoids containing higher number of hydroxyl groups (including 3-OH group of the C ring), such as myricetin (six hydroxyl groups), morin and taxifolin (five hydroxyl groups) in the presence of Cu(II) ions. The proposed mechanism of action by which Cu(II) complexes of myricetin, morin and taxifolin interact with DNA predispose these substances to act as potential anticancer agents. The anticancer activity of phenolic compounds can be explained by their moderate prooxidant properties, which can boost ROS formation and kill cancer cells. Alternatively, slight prooxidant properties may activate antioxidant systems, including antioxidant enzymes and low molecular antioxidants such as glutathione and thus act as preventive anticancer agents

Sorpcja pranej wełny owczej

Sheep wool intended for sorption examination was scoured using three procedures consisting of (1) an ultrasonic tempered bath with tap water, (2) the same as (1) but with detergent, and (3) dichloromethane extraction. The loss of wool mass and removal of Cu, Zn and Pb-cations by the scoured wool as a sorbent were tested. While the loss of mass indicated consistency among all procedures, the cation removal was slightly variable. However, the differences are acceptable, concluding that an ultrasonic water bath without any agent is most favoured. The omission of a detergent or carcinogenic solvent can make the scouring process cleaner and environmentally-friendlier.Wełnę owczą przeznaczoną do badania sorpcji oczyszczono stosując trzy sposoby: (1) kąpiel ultradźwiękowa z użyciem wody wodociągowej; (2) to samo, jak (1), ale z detergentem i (3) ekstrakcja dichlorometanem. Badano utratę masy wełny i usuwanie kationów Cu, Zn i Pb. Podczas, gdy utrata masy występowała we wszystkich trzech przypadkach, usuwanie kationów było nieznacznie zmienne. Stwierdzono, że kąpiel ultradźwiękowa bez jakiegokolwiek środka jest najbardziej optymalna. Pominięcie detergentu lub rakotwórczego rozpuszczalnika może sprawić, że proces prania stanie się bardziej przyjazny dla środowiska

INCREASING OF PROFESSIONAL COMPETENCES OF FUTURE TEACHERS – EDUCATION TO OHS

Nebezpečenstvo je stav alebo charakteru pracovného procesu, ktorý môže poškodiť zdravie študenta alebo zamestnanca. To je dôvod, prečo prevencia - vo forme pravidelných stretnutí organizovaných ako súčasť vzdelávacieho procesu - je nevyhnutná. Cieľom pravidelne organizovaných stretnutí (napr. odborné semináre, prednášky a praktické cvičenia) pre študentov je zoznámiť sa s dôležitosťou vzdelávania v oblasti BOZP (vrátane chemickej bezpečnosti, správnej manipulácie s chemickými látkami, poskytnutím prvej pomoci pri ohrození života a zdravia a neodkladným zásahom pri záchrane majetku). Príspevok poukazuje na dôležitosť vzdelávania v oblasti dodržiavania zásad bezpečnej práce a ochrany zdravia študentov - budúcich učiteľov chémie.The danger is the state or the characteristics of working process that can damage the health of a student or an employee. That is why the prevention – in the form of regular organized sessions as a part of educational process – is inevitable. The aim of the sessions (such as seminars, lectures and as well as practical trainings) for students is to become familiar with the importance of OHS education (including chemical safety, proper manipulation with chemical substances, providing first aid when life-threatening situations take place, as well as immediate intervention when material assets are in danger). The article proves the importance of education in field of respecting the safe work and the prevention of students health – future teachers of chemistry

Structure of catena-diaquatetrakis (µ 2 -3,5-dinitrobenzoato-O,O'- manganese(II))

Abstract The structure of the title compound, [Mn(µ 2 -C 7 H 3 N 2 O 6 ) 2 (H 2 O) 2 ] n (I), has been determined a

Some Properties of Electron Beam-Irradiated Sheep Wool Linked to Cr(III) Sorption

We examined the characteristics of an electron beam irradiated wool with an absorbed dose of (21–410) kGy in comparison with natural wool with respect to the determination of the isoelectric point (IEP), zero charge point (ZCP), mechanism of Cr(III) sorption from higher concentrated solutions, and the modelling of the wool-Cr(III) interaction. The data of ZPC and IEP differed between natural and irradiated samples. Increasing the dose shifted the pH of ZPC from 6.85 for natural wool to 6.20 for the highest dosed wool, while the natural wool IEP moved very little, from pH = 3.35 to 3.40 for all of the irradiated samples. The sorption experiments were performed in a pH bath set at 3.40, and the determination of the residual Cr(III) in the bath was performed by VIS spectrometry under optimized conditions. The resulting sorptivity showed a monotonically rising trend with increasing Cr(III) concentration in the bath. Lower doses, unlike higher doses, showed better sorptivity than the natural wool. FTIR data indicated the formation of complex chromite salts of carboxylates and cysteinates. Crosslinks via ligands coming from different keratin chains were predicted, preferably on the surface of the fibers, but to a degree that did not yet inhibit the diffusion of Cr(III)-cations into the fiber volume. We also present a concept of a complex octahedral structure

Synthesis, crystal structures and properties of coordination polymers from copper(II) adipate

The synthesis, crystal structures and spectroscopy of [{Cu(mu(2)-adip)(benzim)(2)(H2O)}(n)] (1), [{Cu(mu(2)-adip)(4-pyme)(2)(H2O)}(n)] (2), [{Cu(mu(3)-adip)(nia)(2)}(n)center dot nH(2)O] (3), [{Cu(mu(2)-adip)(pydca)(2)}(n)] (4) and [{Cu(mu(4)-adip)(mna)}(n)center dot nH(2)O] (5) (adip = adipate(2-) anion, benzim = benzimidazole, 4-pyme = 4-pyridylmethanol, nia = nicotinamide, pydca = 3,4-pyridinedicarboxamide, mna = N-methylnicotinamide) are reported. The complexes under study were characterized by electronic, IR and EPR spectroscopy, and single-crystal X-ray structure analysis. The complexes form one-dimensional or two-dimensional brick-wall like coordination polymers. The coordination environments around the copper atoms of complexes 1-3 and 5 are distorted tetragonal pyramidal. The copper atom in complex 4 has tetragonal-bipyramidal coordination. Four different coordination modes of adipate ligands in the studied copper(II) complexes were observed. The coordination polymers of the complexes are connected through hydrogen bonds into 2-D or 3-D supramolecular frameworks

Synthesis, Crystal Structure, Spectroscopic Properties and Potential Biological Activities of Salicylate‒Neocuproine Ternary Copper(II) Complexes

Mixed ligand copper(II) complexes containing derivatives of salicylic acid and heterocyclic ligands with nitrogen donor atoms have been the subject of various studies and reviews. In this paper, synthesis and characterization of the ternary copper(II) complexes of neocuproine (2,9-dimethyl-1,10-phenanthroline, Neo) and salicylate ligands (Sal) are reported. In addition, the crystal structures of ([Cu(H2O)(5-Cl-Sal)(Neo)] (1), [Cu(μ-Sal)(Neo)]2 (2), Cu2(μ-5-Cl-Sal)(5-Cl-HSal)2(Neo)2]·EtOH (3)) were determined. In order to compare structural and biological properties of the prepared complexes, spectroscopic and biological studies were performed. Results of X-ray diffraction show that prepared complexes form three types of crystal structures in a given system: monomeric, dimeric and dinuclear complex. The preliminary study on the DNA cleavage activity has shown that the complexes under study behave as the chemical nucleases in the presence of added hydrogen peroxide with slight differences in the activity (1 > 2 > 3). The complexes 1 and 2 exhibited nuclease activity itself indicating the interaction of complexes with the DNA. It has been proposed that the enhanced destructive effect of the complexes 1 and 2 on the DNA is a result of two possible mechanisms of action: (i) the conversion of closed circular DNA (form I) to the nicked DNA (form II) caused by the copper complex itself and (ii) damage of DNA by Reactive Oxygen Species (ROS)—products of the interaction of copper with hydrogen peroxide by means of Fenton reaction (hydroxyl radicals). Thus the biological activity of the prepared Cu(II) complexes containing derivatives of salicylic acid and phenanthroline molecules is substantiated by two independent mechanisms. While derivatives of salicylic acids in the coordination sphere of copper complexes are responsible for radical-scavenging activity (predominantly towards superoxide radical anion), the presence of chelating ligand 2,9-dimethyl-1,10-phenanthroline significantly enhances capability of Cu(II) complexes binding to DNA via intercalation