A Mössbauer study on iron(II) complex of 2-acetyl-1,3-indandione ⎼ spin-crossover or structural changes

An air stable Fe(II) complex of a cyclic β-triketone, 2-acetyl-1,3-indandione (2AID) was obtained in two different ways and studied by Mössbauer spectroscopy. The Mössbauer data at room temperature point to six-coordinated, high spin Fe(II) complex. The temperature-dependent measurements indicate a phase transition in going from 293 to 77 K. Further lowering the temperature, however, do not cause the expected changes for spin-crossover transition. This data provoked application of quantum chemical methods to determine the origin of the observed appearance of spectral component attributable to low spin Fe(II) complex at 77 K. Based on the results from the theoretical calculations of the Mössbauer parameters of several different geometries and spin states of the Fe complexes of 2AID it was possible to conclude that the obtained Fe(II) complex has a pseudo-octahedral geometry. The experimentally observed temperature-dependence of the Mössbauer spectra is attributed to changes of the axial Fe-O bonds, rather than to spin transition. Discussion is given on the role of the type of the axial ligands for conditioning a spin-crossover process, as suggestion for experimental modelling of novel target materials with desired magnetic properties

Dwie twarze islamu. Bułgarscy muzułmanie i wydarzenia z powstania kwietniowego w Cenie złota Ganczo Stoewa i Kałuni-Kali Georgiego Bożinowa

IWELINA MITEWA, MILEN MITEW, bułgarscy filolodzy i komparatyści związani z Wielkotyrnowskim Uniwersytetem Świętych Cyryla i Metodego; Milan Mitew – bułgarski tłumacz z Wielkiego Tyrnowa (jęz. polski, rosyjski, litewski i bułgarski), uczestnik programu „Erasmus” na Uniwersytecie Mikołaja Kopernika w Toruniu. Autor artykułu: (wraz z E. Kubicką, K. Grec i W. Leszczak) Wykorzystanie słowników w interpretacji prawniczej – implikacje praktyczne (2015).Wielkotyrnowski Uniwersytet im. Świętych Cyryla i Metodego, BułgariaВасилев С., Разсъбличането на метафорите. Личности, творби и сюжети в българската литература на ХХ век, В.Т., 2007.Василев С., Цената на златото и на историята, В.Т., 2008.Енев Д., „Калуня-каля“ – забравеният роман шедьовър за Априлското въстание, http://liternet.bg/publish13/d_enev/georgi-bozhinov.htm.Енев Д., Още за Георги Божинов и „Калуня-каля“, http://liternet.bg/publish13/d_enev/kalunia-kalia-2.htm.Кирова М., Завръщането на един свръхгерой, „Култура” 2015, бр. 5, http://www.kultura.bg/bg/article/view/23039.Косев К., Жечев Н., Дойнов Д., История на Априлското въстание 1876, С., 1976.Ничев Д., Стоев Г., Литературни анкети, С., 1983.Българската литературна класика. Литературни портрети и анализи, Пл., 2009, под ред. на Ив. Сарандев, и колектив.Станков Ив., Глад за Голямо, „Литературен вестник” 2015, бр. 4.Трендафилов Вл., Калуня – каля: шедьовърът от кривите улички, „Либерален преглед” z 22.07.2015, http://www.librev.com/index.php/arts-books-publisher/2759-2015-07-22-11- 40-41.Христоматия по история на България. Българско възраждане – втора и трета четвърт на ХІХ век, С., 1996.Шурбанов Ал., Завръщането на Калуньо, „Либерален преглед” z 22.07. 2015.http://www.librev.com/index.php/arts-books-publisher/2759-2015-07-22-11-40-41.43744

On the effect of chelating agents and antioxidants on cadmium-induced organ toxicity. An overview

Cadmium (Cd) has been classified as a human carcinogen. The World Health Organization (WHO) reported that the concentration of Cd in the environment has rapidly increased in the last few years. In many epidemiological studies, the correlation between environmental exposure of humans to Cd and diseases such as stroke, ischemia, renal and hepatic dysfunction, anemia, osteoporosis and diabetes has been discussed. For the treatment of heavy metal intoxications a therapy with chelating agents has been applied. A chelating agent is a compound that binds the toxic metal ion thus promoting its excretion by the living organisms. Recently, it has been found that Cd-induced toxicity is a result of formation of reactive oxygen species (ROS). These results increased the interest towards the antioxidants as possible agents for the treatment of Cd-induced organ toxicity. Herein, we present summary and discussion of the literature data for the influence of chelating agents and antioxidants on Cd-induced pathological conditions in Cd-intoxicated animals

Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin

<p>Abstract</p> <p>Background</p> <p>The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in <it>in vivo </it>experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their <it>in vitro </it>complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II) and lead(II).</p> <p>Results</p> <p>New metal(II) complexes of the polyether ionophorous antibiotic salinomycin with Cd(II) and Pb(II) ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa) undergoes a reaction with heavy metal(II) ions to form [Cd(Sal)₂(H₂O)₂] (<b>1</b>) and [Pb(Sal)(NO₃)] (<b>2</b>), respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II) ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield <b>1</b>. Two salinomycin anions occupy the equatorial plane of the Cd(II) center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II) cation. Complex <b>2 </b>consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation.</p> <p>Conclusion</p> <p>The formation of the salinomycin heavy metal(II) complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock farming.</p

X-Ray and EPR study on copper (II) complexes with an enamine ligand

AbstractThe enamine (HEAID) obtained from aniline and 2-acetyl-1,3-indandione (2AID) behaves as a bidentate ligand in coordination with copper (II) ion. Two types of crystals, apparently different in shape, were isolated and studied by single-crystal X-ray diffraction. The X-ray data for the brown rhombic crystals of compound 1 shows a mononuclear complex of Cu(II) coordinated with two EAID-anions, Cu(EAID)2. The X-ray data for the green crystals of compound 2 shows a dinuclear Cu(II) complex with two OH− groups acting as bridging ligands, [Cu2(μ-OH)2(EAID)2]. In both cases the ligand coordinates after deprotonation of the amine group