Ytterbium and Europium Complexes of Redox-Active Ligands: Searching for Redox Isomerism

© 2017 American Chemical Society. The reaction of (dpp-Bian)Eu II (dme) 2 (3) (dpp-Bian is dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; dme is 1,2-dimethoxyethane) with 2,2′-bipyridine (bipy) in toluene proceeds with replacement of the coordinated solvent molecules with neutral bipy ligands and affords europium(II) complex (dpp-Bian)Eu II (bipy) 2 (9). In contrast the reaction of related ytterbium complex (dpp-Bian)Yb II (dme) 2 (4) with bipy in dme proceeds with the electron transfer from the metal to bipy and results in (dpp-Bian)Yb III (bipy)(bipy - ). (10) - ytterbium(III) derivative containing both neutral and radical-anionic bipy ligands. Noteworthy, in both cases dianionic dpp-Bian ligands retain its reduction state. The ligand-centered redox-process occurs when complex 3 reacts with N,N′-bis[2,4,6-trimethylphenyl]-1,4-diaza-1,3-butadiene (mes-dad). The reaction product (dpp-Bian)Eu II (mes-dad)(dme) (11) consists of two different redox-active ligands both in the radical-anionic state. The reduction of 3,6-di-tert-butyl-4-(3,6-di-tert-butyl-2-ethoxyphenoxy)-2-ethoxycyclohexa-2,5-dienone (the dimer of 2-ethoxy-3,6-di-tert-butylphenoxy radical) with (dpp-Bian)Eu II (dme) 2 (3) caused oxidation of the dpp-Bian ligand to radical-anion to afford (dpp-Bian)(ArO)Eu II (dme) (ArO = OC 6 H 2 -3,6-tBu 2 -2-OEt) (12). The molecular structures of complexes 9-12 have been established by the single crystal X-ray analysis. The magnetic behavior of newly prepared compounds has been investigated by the SQUID technique in the range 2-310 K. The isotropic exchange model has been adopted to describe quantitatively the magnetic properties of the exchange-coupled europium(II) complexes (11 and 12). The best-fit isotropic exchange parameters are in good agreement with their density functional theory-computed counterparts

Hygienic assessment of environmental factors that cause insufficient provision with vitamins among pre-school children

An issue related to insufficient provision with vitamins among children in Russia requires profound examination, especially as regards reasons for it, as it will allow to work out targeted prevention measures. Our research goal was to perform hygienic assessment of environmental factors (organization of nutrition, chemical contamination of environmental objects) that influence provision of pre-school children with vitamins. We chose the following research objects: a typical pre-school children facility located in a large industrial center and 188 children aged 6–7 who attended it. We applied a set of sanitary-hygienic, laboratory, and mathematical techniques in our research. We assessed organization of nutrition in the facility; performed a comparative analysis of nutrition quality with calculation and individual weighting technique. We also examined concentrations of technogenic chemicals in the atmospheric air, the air inside the facility, and water supplied to the facility; determined their concentrations in children's blood; studied antioxidant protection system in children and a level of their provision with vitamins. We detected that nutrition in the facility was imbalanced, and actual consumption of some food products was up to 1.7 times lower that it was suggested in a menu, and actual introduction of vitamins was by 30 % lower than calculated one. We showed that environmental objects (the atmospheric air, indoor air, and drinking water supplied to the facility) on industrially developed territories were contaminated with technogenic chemicals (formaldehyde, phenol, ethylbenzene, chloroform, and residual free/fixed chlorine) and it led to occurrence of their increased concentrations and increased concentrations of their metabolites in children's blood. We proved that increased concentrations of oxygen-containing aldehydes, aromatic hydrocarbons, and chlorine-organic compounds in children's blood made antioxidant protection enzymes less active and caused lower concentrations of antioxidant-active vitamins. So, insufficient provision with vitamins among pre-school children who attend a pre-school children facility in a large industrial center is caused not only by insufficient exogenous introduction of vitamins with food but also by effects of their metabolic absorption related to occurrence of technogenic chemicals with pro-oxidant effects in biological media

Violation of homeostasis of the main types of exchange and immune resistance status in children with subclinical hypovitaminosis in conditions of exposure to chemical environmental factors

The study of the chemical substances’ content of anthropogenic origin in children with subclinical polyhypovitaminosis was conducted. It was found that a deficiency of vitamins A, C, E, B6 and B12 increases the risk of developing of elevated concentrations of organic substances of technogenic origin in blood in 1.4–6.9 times. In children with subclinical polyhypovitaminosis and high blood phenol, formaldehyde, aromatic hydrocarbons, and organ chlorine compounds increases the tension of erythropoiesis, decreases the activity of proliferating processes of lympfomonocytic germ cell factors of nonspecific resistance. Even subclinical forms of polyhypovitaminosis on the background of high content of organic compounds in the blood of children are accompanied by a slowdown of protein and carbohydrate metabolism, depletion of antioxidant defense system of reserves and shortage of energy metabolism. Developing disorders of fat metabolism in children with subclinical polyhypovitaminosis occur against a background of strained reactions of hormonal regulation that, in case of the progressive course may pose a threat to the early development of cardiovascular disease in older age groups

Ytterbium and Europium Complexes of Redox-Active Ligands: Searching for Redox Isomerism

© 2017 American Chemical Society. The reaction of (dpp-Bian)Eu II (dme) 2 (3) (dpp-Bian is dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; dme is 1,2-dimethoxyethane) with 2,2′-bipyridine (bipy) in toluene proceeds with replacement of the coordinated solvent molecules with neutral bipy ligands and affords europium(II) complex (dpp-Bian)Eu II (bipy) 2 (9). In contrast the reaction of related ytterbium complex (dpp-Bian)Yb II (dme) 2 (4) with bipy in dme proceeds with the electron transfer from the metal to bipy and results in (dpp-Bian)Yb III (bipy)(bipy - ). (10) - ytterbium(III) derivative containing both neutral and radical-anionic bipy ligands. Noteworthy, in both cases dianionic dpp-Bian ligands retain its reduction state. The ligand-centered redox-process occurs when complex 3 reacts with N,N′-bis[2,4,6-trimethylphenyl]-1,4-diaza-1,3-butadiene (mes-dad). The reaction product (dpp-Bian)Eu II (mes-dad)(dme) (11) consists of two different redox-active ligands both in the radical-anionic state. The reduction of 3,6-di-tert-butyl-4-(3,6-di-tert-butyl-2-ethoxyphenoxy)-2-ethoxycyclohexa-2,5-dienone (the dimer of 2-ethoxy-3,6-di-tert-butylphenoxy radical) with (dpp-Bian)Eu II (dme) 2 (3) caused oxidation of the dpp-Bian ligand to radical-anion to afford (dpp-Bian)(ArO)Eu II (dme) (ArO = OC 6 H 2 -3,6-tBu 2 -2-OEt) (12). The molecular structures of complexes 9-12 have been established by the single crystal X-ray analysis. The magnetic behavior of newly prepared compounds has been investigated by the SQUID technique in the range 2-310 K. The isotropic exchange model has been adopted to describe quantitatively the magnetic properties of the exchange-coupled europium(II) complexes (11 and 12). The best-fit isotropic exchange parameters are in good agreement with their density functional theory-computed counterparts

Ytterbium and Europium Complexes of Redox-Active Ligands: Searching for Redox Isomerism

© 2017 American Chemical Society. The reaction of (dpp-Bian)Eu II (dme) 2 (3) (dpp-Bian is dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; dme is 1,2-dimethoxyethane) with 2,2′-bipyridine (bipy) in toluene proceeds with replacement of the coordinated solvent molecules with neutral bipy ligands and affords europium(II) complex (dpp-Bian)Eu II (bipy) 2 (9). In contrast the reaction of related ytterbium complex (dpp-Bian)Yb II (dme) 2 (4) with bipy in dme proceeds with the electron transfer from the metal to bipy and results in (dpp-Bian)Yb III (bipy)(bipy - ). (10) - ytterbium(III) derivative containing both neutral and radical-anionic bipy ligands. Noteworthy, in both cases dianionic dpp-Bian ligands retain its reduction state. The ligand-centered redox-process occurs when complex 3 reacts with N,N′-bis[2,4,6-trimethylphenyl]-1,4-diaza-1,3-butadiene (mes-dad). The reaction product (dpp-Bian)Eu II (mes-dad)(dme) (11) consists of two different redox-active ligands both in the radical-anionic state. The reduction of 3,6-di-tert-butyl-4-(3,6-di-tert-butyl-2-ethoxyphenoxy)-2-ethoxycyclohexa-2,5-dienone (the dimer of 2-ethoxy-3,6-di-tert-butylphenoxy radical) with (dpp-Bian)Eu II (dme) 2 (3) caused oxidation of the dpp-Bian ligand to radical-anion to afford (dpp-Bian)(ArO)Eu II (dme) (ArO = OC 6 H 2 -3,6-tBu 2 -2-OEt) (12). The molecular structures of complexes 9-12 have been established by the single crystal X-ray analysis. The magnetic behavior of newly prepared compounds has been investigated by the SQUID technique in the range 2-310 K. The isotropic exchange model has been adopted to describe quantitatively the magnetic properties of the exchange-coupled europium(II) complexes (11 and 12). The best-fit isotropic exchange parameters are in good agreement with their density functional theory-computed counterparts

Current Design of Mixed-Ligand Complexes of Magnesium(II): Synthesis, Crystal Structure, Thermal Properties and Biological Activity against <i>Mycolicibacterium Smegmatis</i> and <i>Bacillus Kochii</i>

The interaction of Mg2+ with 2-furoic acid (HFur) and oligopyridines, depending on the synthesis conditions, leads to the formation of mixed-ligand complexes [Mg(H2O)4(phen)]·2HFur·phen·H2O (1), [Mg(NO3)2(phen)2] (2) and [Mg3(Fur)6(bpy)2]·3CH3CN (3); these structures were determined with an SC X-ray analysis. According to the X-ray diffraction data, in complex 1, obtained in ambient conditions, the magnesium cation coordinated four water molecules and one phenanthroline fragment, while in complexes 2 and 3 (synthesized in an inert atmosphere), the ligand environment of the complexing agent was represented by neutral oligopyridine molecules and acid anions. The thermal behavior of 1 and 2 was studied using a simultaneous thermal analysis (STA). The in vitro biological activity of complexes 1–3 was studied in relation to the non-pathogenic Mycolicibacterium smegmatis and the virulent strain Mycobacterium tuberculosis H37Rv

Ytterbium and Europium Complexes of Redox-Active Ligands: Searching for Redox Isomerism

The reaction of (dpp-Bian)­Eu^II(dme)₂ (<b>3</b>) (dpp-Bian is dianion of 1,2-bis­[(2,6-diisopropylphenyl)­imino]­acenaphthene; dme is 1,2-dimethoxyethane) with 2,2′-bipyridine (bipy) in toluene proceeds with replacement of the coordinated solvent molecules with neutral bipy ligands and affords europium­(II) complex (dpp-Bian)­Eu^II(bipy)₂ (<b>9</b>). In contrast the reaction of related ytterbium complex (dpp-Bian)­Yb^II(dme)₂ (<b>4</b>) with bipy in dme proceeds with the electron transfer from the metal to bipy and results in (dpp-Bian)­Yb^III(bipy)­(bipy^–̇) (<b>10</b>) – ytterbium­(III) derivative containing both neutral and radical-anionic bipy ligands. Noteworthy, in both cases dianionic dpp-Bian ligands retain its reduction state. The ligand-centered redox-process occurs when complex <b>3</b> reacts with <i>N</i>,<i>N</i>′-bis­[2,4,6-trimethylphenyl]-1,4-diaza-1,3-butadiene (mes-dad). The reaction product (dpp-Bian)­Eu^II­(mes-dad)­(dme) (<b>11</b>) consists of two different redox-active ligands both in the radical-anionic state. The reduction of 3,6-di-<i>tert</i>-butyl-4-(3,6-di-<i>tert</i>-butyl-2-ethoxyphenoxy)-2-ethoxycyclohexa-2,5-dienone (the dimer of 2-ethoxy-3,6-di-<i>tert</i>-butylphenoxy radical) with (dpp-Bian)­Eu^II(dme)₂ (<b>3</b>) caused oxidation of the dpp-Bian ligand to radical-anion to afford (dpp-Bian)­(ArO)­Eu^II(dme) (ArO = OC₆H₂-3,6-<i>t</i>Bu₂-2-OEt) (<b>12</b>). The molecular structures of complexes <b>9</b>–<b>12</b> have been established by the single crystal X-ray analysis. The magnetic behavior of newly prepared compounds has been investigated by the SQUID technique in the range 2–310 K. The isotropic exchange model has been adopted to describe quantitatively the magnetic properties of the exchange-coupled europium­(II) complexes (<b>11</b> and <b>12</b>). The best-fit isotropic exchange parameters are in good agreement with their density functional theory-computed counterparts

&alpha;-Diimine Cisplatin Derivatives: Synthesis, Structure, Cyclic Voltammetry and Cytotoxicity

Three new Pt(II) complexes [(dpp-DAD)PtCl2] (I), [(Mes-DAD(Me)2)PtCl2] (II) and [(dpp-DAD(Me)2)PtCl2] (III) were synthesized by the direct reaction of [(CH3CN)2PtCl2] and corresponding redox-active 1,4-diaza-1,3-butadienes (DAD). The compounds were isolated in a single crystal form and their molecular structures were determined by X-ray diffraction. The purity of the complexes and their stability in solution was confirmed by NMR analysis. The Pt(II) ions in all compounds are in a square planar environment. The electrochemical reduction of complexes I&ndash;III proceeds in two successive cathodic stages. The first quasi-reversible reduction leads to the relatively stable monoanionic complexes; the second cathodic stage is irreversible. The coordination of 1,4-diaza-1,3-butadienes ligands with PtCl2 increases the reduction potential and the electron acceptor ability of the DAD ligands. The synthesized compounds were tested in relation to an adenocarcinoma of the ovary (SKOV3)