Removal of Co(II) from aqueous solution by using hydroxyapatite

International Nuclear Information System (INIS)

Yan Huang; Liang Chen; Hualin Wang

2012-01-01

Herein, hydroxyapatite (HAP) was prepared by aqueous precipitation technique and was characterized by using FT-IR and XRD to determine its chemical functional groups and micro-structure. The removal of cobalt from aqueous solution to HAP was studied by batch technique as a function of various environmental parameters such as contact time, pH, ionic strength, foreign ions, fulvic acid (FA), and temperature under ambient conditions. The results indicated that the sorption of Co(II) on HAP was strongly dependent on pH and ionic strength. The presence of FA enhanced the sorption of Co(II) on HAP at low pH, whereas reduced Co(II) sorption on HAP at high pH. The Langmuir, Freundlich and D-R models were used to simulate the sorption isotherms at three different temperatures of 303.15, 323.15 and 343.15 K. The thermodynamic parameters (ΔHdeg, ΔSdeg and ΔGdeg) calculated from the temperature dependent sorption isotherms indicated that the sorption process of Co(II) on HAP was spontaneous and endothermic. The sorption of Co(II) was dominated by outer-sphere surface complexation and ion exchange at low pH, whereas inner-sphere surface complexation or surface precipitation was the main sorption mechanism at high pH values. The results suggest that the HAP is a suitable material in the preconcentration and solidification of Co(II) from large volumes of aqueous solutions. (author)

Secondary ligand-directed assembly of Co(II) coordination polymers based on a pyridine carboxylate ligand

International Nuclear Information System (INIS)

Cao, Ke-Li; Zhang, Yi-Ping; Cai, Yi-Ni; Xu, Xiao-Wei; Feng, Yun-Long

2014-01-01

To investigate the influence of hydrogen bonds and secondary ligands on the structures and properties of the resulting frameworks, five new Co(II) compounds have been synthesized by the reactions of Co(II) salts and 3,5-bis(pyridin-4-ylmethoxy)benzoic acid (HL) with four rationally selected dicarboxylic acid ligands. Without secondary ligand, we got one compound [CoL 2 (H 2 O) 2 ] n ·2nH 2 O (1), which possesses a 1D chain structure. In the presence of ancillary ligands, namely, 1,3-adamantanedicarboxylic acid (H 2 adbc), terephthalic acid (H 2 tpa), thiophene-2,5-dicarboxylic acid (H 2 tdc) and 1,4-benzenedithioacetic acid (H 2 bdtc), four 3D structures [Co 2 L 2 (adbc)] n ·nH 2 O (2), [Co 2 L 2 (tpa)] n (3), [Co 2 L 2 (tdc)] n (4), [Co 2 L 2 (bdtc)(H 2 O)] n (5) were obtained, respectively. It can be observed from the architectures of 1–5 that hydrogen bonds and secondary ligands both have great effects on the spatial connective fashions, resulting in the formation of various dimensional compounds. The XRPD, TGA data of title polymers and the magnetic properties for 2 and 5 have also been investigated. - Graphical abstract: The structural differences show that the ancillary ligands have great effects on the spatial connective fashions, resulting in the formation of various dimensional compounds. - Highlights: • Five new Co(II) coordination polymers have been synthesized by solvothermal reactions based on 3,5-bis(pyridin-4-ylmethoxy)benzoic acid (HL). • The long-flexible ligand (HL) is a good candidate to produce interpenetrating architectures. • The secondary dicarboxylic acid ligands play important roles in the spatial connective fashions and the formation of various dimensional compounds. • The magnetism studies show that both 2 and 5 exhibit antiferromagnetic interactions

Structural and antimicrobial studies of coordination compounds of VO(II, Co(II, Ni(II and Cu(II with some Schiff bases involving 2-amino-4-chlorophenol

Directory of Open Access Journals (Sweden)

A. P. MISHRA

2009-05-01

Full Text Available Complexes of tailor-made ligands with life essential metal ions may be an emerging area to answer the problem of multi-drug resistance (MDR. The coordination complexes of VO(II, Co(II, Ni(II and Cu(II with the Schiff bases derived from 2-hydroxyacetophenone/2-chlorobenzaldehyde with 2-ami¬no-4-chlorophenol were synthesized and characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, ESR, FAB mass, thermal and magnetic susceptibility measurements. The FAB mass and thermal data show degradation of the complexes. The ligand A (2-hydroxyacetophenone-2amino-4-chlorophenol behaved as tridentate and ligand B (2-chlorobenzylidene-2-amino-4-chlorophenol as bidentate, coordinating through O and N donors. The complexes [VO(A(H2O]×xH2O, [M(A(H2On]×xH2O for Co and Ni, [Cu(A(H2O] and [VO(B2]×xH2O, [M(B2(H2On] for Co and Cu and [Ni(B2] exhibited coordination numbers 4, 5 or 6. X-ray powder diffraction data (a = 11.00417 Å, b = 11.706081 Å and c = 54.46780 Å showed that [Cu(CACP2(H2O2], complex 8, crystallized in the orthorhombic system. The in vitro biological screening effects of the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus and Streptococcus fecalis and the fungi Aspergillus niger, Trichoderma polysporum and Candida albicans by the serial dilution method. A comparative study of the MIC values of the Schiff base and their [M(B2(H2O2] complexes (Co(II, complex 6 and Cu(II, complex 8, indicated that the metal complexes exhibited a higher or lower antimicrobial activity than 2-chlorobenzylidene-2-amino-4-chlorophenol as the free ligand (B.

Efficient removal of Co(II) from aqueous solution by titanate sodium nanotubes

Institute of Scientific and Technical Information of China (English)

Dong-Mei Li; Ning Liu; Fei-Ze Li; Jia-Li Liao; Ji-Jun Yang; Bing Li; Yun-Ming Chen; Yuan-You Yang; Jin-Song Zhang; Jun Tang

2016-01-01

In this paper, a novel material for Co(II) adsorption, titanate sodium nanotubes (Na2Ti2O5-NTs) were synthesized and characterized, and then they were used to remove Co(II) from aqueous solution and compared with titanic acid nanotubes (H2Ti2O5-NTs) and potassium hexatitanate whiskers (K2Ti6O13). The results showed that the adsorption of Co(II) on the materials was dependent on pH values and was a spontaneous, endothermic process. Specifically, Na2Ti2O5-NTs exhibited much more efficient ability to adsorb Co(II) from aqueous solution, with the maximum adsorption capacity of 85.25 mg/g. Furthermore, Na2Ti2O5-NTs could selectively adsorb Co(II) from aque-ous solution containing coexisting ions (Na+, K+, Mg2+, and Ca2+). The results suggested that Na2Ti2O5-NTs were potential effective adsorbents for removal of Co(II) or cobalt-60 from wastewater.

Bowl adamanzanes-bicyclic tetraamines: syntheses and crystal structures of complexes with cobalt(III) and chelating coordinated oxo-anions

DEFF Research Database (Denmark)

Broge, Louise; Søtofte, Inger; Jensen, Kristian

2007-01-01

complex is provided. Four of the seven complexes contain a chelate coordinating oxo-anion ( sulfate, formiate, nitrate, carbonate). Equilibration of these species with the corresponding diaqua complex is generally slow. The rates of equilibration in 5 mol dm(-3) perchloric acid at 25 degrees C have been...

Synthesis, Crystal Structure, Luminescence, Electrochemical and Antimicrobial Properties of Bis(salamo-Based Co(II Complex

Directory of Open Access Journals (Sweden)

Li Wang

2017-09-01

Full Text Available A newly designed Co(II complex, [Co3(L(OAc2(CH3OH2]·CH3OH, by the reaction of a bis(salamo-type tetraoxime ligand (H4L with Co(II acetate tetrahydrate was synthesized and characterized by elemental analyses, IR, UV-vis spectra and single-crystal X-ray crystallography. The UV-vis titration experiment manifested that a trinuclear (L:M = 1:3 complex was formed. It is worth noting that the two terminal Co(II (Co1 and Co3 atoms of the Co(II complex have different coordination modes and geometries unreported earlier. Furthermore, through intermolecular interactions (C–H···O, C–H···π and O–H···O, a 2D layer-like network is constructed. In addition, the fluorescence behaviors, antimicrobial activities and electrochemical properties of H4L and its Co(II complex were investigated.

Thermal, spectral, magnetic and biological studies of thiosemicarbazones complexes with metal ions: Cu(II), Co(II), Ni(II), Fe(III), Zn(II), Mn(II) and UO2(VI)

International Nuclear Information System (INIS)

Mashaly, M.M.; Seleem, H.S.; El-Behairy, M.A.; Habib, H.A.

2004-01-01

Thiosemicarbazones ligands, isatin-3-thiosemicarbazone(HIT) and N-acetylisatin-3-thiosemicarbazone (HAIT), which have tridentate ONN coordinating sites were prepared. The complexes of both ligands with Cu(II), Co(II), Ni(II), Fe(III), Zn(II), Mn(II) and UO 2 (VI) ions were isolated. The ligands and their metal complexes were characterized by elemental analysis, IR, UV-Vis and mass spectra, also by conductance, magnetic moment and TG-DSC measurements. All the transition metal complexes have octahedral configurations, except Cu-complexes which have planar geometry and the UO 2 (VI) complexes which have coordination number 8 and may acquire the distorted dodecahedral geometry. Thermal studies explored the possibility of obtaining new complexes. Inversion from octahedral to square-planar configuration occurred upon heating the parent Ni-HIAT complex to form the corresponding pyrolytic product. The antifungal activity against the tested organisms showed that some metal complexes enhanced the activity with respect to the parent ligands. (author)

Synthesis, investigation and spectroscopic characterization of piroxicam ternary complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with glycine and DL-phenylalanine

Science.gov (United States)

Mohamed, Gehad G.; El-Gamel, Nadia E. A.

2004-11-01

The ternary piroxicam (Pir; 4-hydroxy-2-methyl- N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with various amino acids (AA) such as glycine (Gly) or DL-phenylalanine (PhA) were prepared and characterized by elemental analyses, molar conductance, IR, UV-Vis, magnetic moment, diffuse reflectance and X-ray powder diffraction. The UV-Vis spectra of Pir and the effect of metal chelation on the different interligand transitions are discussed in detailed manner. IR and UV-Vis spectra confirm that Pir behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine- N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its carboxylic group, in addition PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its carboxylic and amino groups. All the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. The molar conductance data reveal that most of these chelates are non electrolytes, while Fe(III)-Pir-Gly, Co(II)-, Ni(II)-, Cu(II)- and Zn(II)-Pir-PhA cheletes were 1:1 electrolytes. X-ray powder diffraction is used as a new tool to estimate the crystallinity of chelates as well as to elucidate their geometrical structures.

Anion mediated polytype selectivity among the basic salts of Co(II)

Science.gov (United States)

Ramesh, T. N.; Rajamathi, Michael; Vishnu Kamath, P.

2006-08-01

Basic salts of Co(II) crystallize in the rhombohedral structure. Two different polytypes, 3R 1 and 3R 2, with distinct stacking sequences of the metal hydroxide slabs, are possible within the rhombohedral structure. These polytypes are generated by simple translation of successive layers by (2/3, 1/3, z) or (1/3, 2/3, z). The symmetry of the anion and the mode of coordination influences polytype selection. Cobalt hydroxynitrate crystallizes in the structure of the 3R 2 polytype while the hydroxytartarate, hydroxychloride and α-cobalt hydroxide crystallize in the structure of the 3R 1 polytype. Cobalt hydroxysulfate is turbostratically disordered. The turbostratic disorder is a direct consequence of the mismatch between the crystallographically defined interlayer sites generated within the crystal and the tetrahedral symmetry of the SO 42- ions.

Mono- and polynuclear Co(II) silanethiolates with aliphatic diamines

Science.gov (United States)

Pladzyk, Agnieszka; Baranowska, Katarzyna

2014-01-01

Four Co(II) complexes, [Co{SSi(OtBu)3}2(dmpda)] 1, [Co{SSi(OtBu)3}2(bda)2]n2 [Co{SSi(OtBu)3}2(pda)2]n3 and [Co{SSi(OtBu)3}2(hda)2]n4 [dmpda = 3-(dimethylamino)-1-propylamine; bda = 1.4-butanediamine; pda = 1.5-pentanediamine; had = 1.6-hexanediamine] have been synthesized and characterized using X-ray diffraction. Complex 1 is mononuclear and contains Co(II) coordinated by dmpda molecule in chelating mode, whereas compounds 3 and 4 are one-dimensional polymers with pda and hda diamines as bridges between the metallic centers respectively. In all complexes tri-tert-butoxysilanethiolate residue acts as terminal S-donor ligand. Full characterization of obtained compounds 1-4 was additionally carried out with the use of IR and UV-vis spectroscopy, elemental and thermal analysis.

Synthesis and spectral studies of manganese(II), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and mercury(II) complexes of 4-oxo-4H-1-benzopyran-3-carboxaldehyde hydrazone derivatives

International Nuclear Information System (INIS)

Nawar, N.; Khattab, M.A.; Bekheit, M.M.; El-Kaddah, A.H.

1996-01-01

A few complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) with 4-oxo-4H-1-benzopyran-3-(carboxaldehyde-4-chlorobenzylhydrazone) (BCBH) and 4-oxo-4H-1-benzopyran-3-(carboxaldehyde-4-methylbenzylhydrazone) (BMBH) have been synthesised and characterized by elemental analysis, molar conductivities, magnetic measurements and infrared (IR) and visible spectral studies. The IR spectra show that BCBH and BMBH behave as bidentate ligands either in the keto or enol form. (author). 24 refs., 2 tabs

New insights into thorium and uranium oxo-arsenic (III/V) and oxo-phosphates (V) crystal chemistry

International Nuclear Information System (INIS)

Yu, Na

2015-01-01

The fundamental chemistry of actinides is of great interest owing to the diverse number of valence states and complex coordination chemistry of the actinides. The phases based on actinides and oxo-salt fragments have been under thorough investigation in the last decades. These compounds can be widely found in nature and they affect the migration process of actinides in nature. A better understanding of the fundamental coordination chemistry of actinide compounds with oxo-salts of group V elements is not only important for understanding the actinides behavior within the migration process but can also be used to understand actinide properties in phosphate ceramics. Concerning the radioactive issues, the less radioactive early actinides (i.e. U, Th) can be taken as modeling elements to study the crystal chemistry of the transuranic elements (Np, Pu) without the major handling problems. This can be done as Th(IV) has a very similar coordination chemistry with An(IV) and U(VI) can be chosen as a modeling element for transuranic elements in higher valence states. Therefore, a systematic research on the actinides (U, Th) bearing phases with tetrahedral oxo-anions such as phosphates and arsenates have been performed in this work. High temperature (HT) solid state reaction, High pressure high temperature (HP-HT) solid state reaction and the hydrothermal method were the methods of choice for synthesizing actinide bearing oxo-arsenic(III/V) and oxo- phosphorus(V) phases in the past three years. As a result, numerous novel compounds containing actinides were obtained. The structures of all compounds were determined using single crystal X-ray diffraction data. Raman spectroscopy, EDS, DSC and high temperature powder X-ray diffraction (HT-PXRD) measurements were implemented to characterize the chemical and physical properties of the obtained compounds. The core of this dissertation is a fundamental study of the crystal chemistry of actinides (Th, U) oxo-arsenic (III/V) and oxo

Metal-ion exchange induced structural transformation as a way of forming novel Ni(II)− and Cu(II)−salicylaldimine structures

Energy Technology Data Exchange (ETDEWEB)

Wu, Jing-Yun, E-mail: jyunwu@ncnu.edu.tw; Tsai, Chi-Jou; Chang, Ching-Yun; Wu, Yung-Yuan

2017-02-15

A Zn(II)−salicylaldimine complex [Zn(L{sup salpyca})(H{sub 2}O)]{sub n} (1, where H{sub 2}L{sup salpyca}=4-hydroxy-3-(((pyridin-2-yl)methylimino)methyl)benzoic acid), with a one-dimensional (1D) chain structure, has been successfully converted to a discrete Ni(II)−salicylaldimine complex [Ni(L{sup salpyca})(H{sub 2}O){sub 3}] (2) and an infinite Cu(II)−salicylaldimine complex ([Cu(L{sup salpyca})]·3H{sub 2}O){sub n} (3) through a metal-ion exchange induced structural transformation process. However, such processes do not worked by Mn(II) and Co(II) ions. Solid-state structure analyses reveal that complexes 1–3 form comparable coordinative or supramolecular zigzag chains running along the crystallographic [201] direction. In addition, replacing Zn(II) ion by Ni(II) and Cu(II) ions caused changes in coordination environment and sphere of metal centers, from a 5-coordinate intermediate geometry of square pyramidal and trigonal bipyramidal in 1 to a 6-coordinate octahedral geometry in 2, and to a 4-coordiante square planar geometry in 3. This study shows that metal-ion exchange serves as a very efficient way of forming new coordination complexes that may not be obtained through direct synthesis. - Graphical abstract: A Zn(II)−salicylaldimine zigzag chain has been successfully converted to a Ni(II)−salicylaldimine supramolecular zigzag chain and a Cu(II)−salicylaldimine coordinative zigzag chain through metal-ion exchange induced structural transformations, which is not achieved by Mn(II) and Co(II) ions.

Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of Co(II)- picolinate complex

Energy Technology Data Exchange (ETDEWEB)

Tamer, Ömer, E-mail: omertamer@sakarya.edu.tr; Avcı, Davut; Atalay, Yusuf

2015-11-15

A cobalt(II) complex of picolinate was synthesized, and its structure was fully characterized by the applying of X-ray diffraction method as well as FT-IR, FT-Raman and UV–vis spectroscopies. In order to both support the experimental results and convert study to more advanced level, density functional theory calculations were performed by using B3LYP level. Single crystal X-ray structural analysis shows that cobalt(II) ion was located to the center of distorted octahedral geometry. The C=O, C=C and C=N stretching vibrations were found as highly active and strong peaks, inducing the molecular charge transfer within Co(II) complex. The small energy gap between frontier molecular orbital energies was another indicator of molecular charge transfer interactions within Co(II) complex. The nonlinear optical properties of Co(II) complex were investigated at DFT/B3LYP level, and the hypepolarizability parameter was found to be decreased due to the presence of inversion symmetry. The natural bond orbital (NBO) analysis was performed to investigate molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength for Co(II) complex. Finally, molecular electrostatic potential (MEP) and spin density distributions for Co(II) complex were evaluated. - Highlights: • Co(II) complex of picolinate was prepared. • Its FT-IR, FT-Raman and UV–vis spectra were measured. • DFT calculations were performed to support experimental results. • Small HOMO-LUMO energy gap is an indicator of molecular charge transfer. • Spin density localized on Co(II) as well as O and N atoms.

Hydration energies and specific influence of oxo complexes and high coordination numbers on the predicted chemistry of superheavy elements

International Nuclear Information System (INIS)

Jorgensen, C.K.; Penneman, R.A.

1975-01-01

On the basis of an analysis of the known ionization energies of gaseous ions and aqua ions of the 3d, 4f, and 6d transition groups and the radius effects, the chemistry of the superheavy elements is predicted. The formation of aqua ion and oxo complexes in the elements with Z below 121 is considered. It is probable that the series from 123 to 140 constitute a close analogy to the lanthanides with Th-like chemistry. Above Z = 140 the elements will probably displace a transition group behavior. A brief comment is made on the analytical aspects to be expected. (U.S.)

Unprecedented Hexanuclear Cobalt(II Nonsymmetrical Salamo-Based Coordination Compound: Synthesis, Crystal Structure, and Photophysical Properties

Directory of Open Access Journals (Sweden)

Zong-Li Ren

2018-03-01

Full Text Available A novel hexanuclear Co(II coordination compound with a nonsymmetrical Salamo-type bisoxime ligandH4L, namely [{Co3(HL(MeO(MeOH2(OAc2}2]·2MeOH, was prepared and characterized by elemental analyses, UV–vis, IR and fluorescence spectra, and X-ray single-crystal diffraction analysis. Each Co(II is hexacoordinated, and possesses a distorted CoO6 or CoO4N2 octahedrons. The Co(II coordination compound possesses a self-assembled infinite 2D supramolecular structure with the help of the intermolecular C–H···O interactions. Meanwhile, the photophysical properties of the Co(II coordination compound were studied.

Preparation, characterization of electrospun meso-hydroxylapatite nanofibers and their sorptions on Co(II)

Energy Technology Data Exchange (ETDEWEB)

Wang, Hualin, E-mail: hlwang@hfut.edu.cn [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China); Zhang, Peng; Ma, Xingkong; Jiang, Suwei; Huang, Yan; Zhai, Linfeng [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China); Jiang, Shaotong [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China)

2014-01-30

Highlights: • PVA/HA nanofibers could change into meso-HA nanofibers by calcination process. • Sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. • Sorption kinetic data were well fitted by the pseudo-second-order rate equation. • Sorption isotherms could be well described by the Langmuir model. • Sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic. -- Abstract: In this work, mesoporous hydroxylapatite (meso-HA) nanofibers were prepared via calcination process with polyvinyl alcohol/HA (PVA/HA) hybrid nanofibers fabricated by electrospinning technique as precursors, and the removal efficiency of meso-HA nanofibers toward Co(II) was evaluated via sorption kinetics and sorption isotherms. Furthermore, the sorption behaviors of Co(II) on meso-HA nanofibers were explored as a function of pH, ionic strength, and thermodynamic parameters. There existed hydrogen bonds between HA and PVA matrix in precursor nanofibers which could change into meso-HA nanofibers with main pore diameter at 27 nm and specific surface area at 114.26 m{sup 2}/g by calcination process. The sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. Outer-sphere surface complexation or ion exchange was the main mechanisms of Co(II) adsorption on meso-HA at low pH, whereas inner-sphere surface complexation was the main adsorption mechanism at high pH. The sorption kinetic data were well fitted by the pseudo-second-order rate equation. The sorption isotherms could be well described by the Langmuir model. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the temperature-dependent sorption isotherms suggested that the sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic.

Anion mediated polytype selectivity among the basic salts of Co(II)

International Nuclear Information System (INIS)

Ramesh, T.N.; Rajamathi, Michael; Vishnu Kamath, P.

2006-01-01

Basic salts of Co(II) crystallize in the rhombohedral structure. Two different polytypes, 3R 1 and 3R 2 , with distinct stacking sequences of the metal hydroxide slabs, are possible within the rhombohedral structure. These polytypes are generated by simple translation of successive layers by (2/3, 1/3, z) or (1/3, 2/3, z). The symmetry of the anion and the mode of coordination influences polytype selection. Cobalt hydroxynitrate crystallizes in the structure of the 3R 2 polytype while the hydroxytartarate, hydroxychloride and α-cobalt hydroxide crystallize in the structure of the 3R 1 polytype. Cobalt hydroxysulfate is turbostratically disordered. The turbostratic disorder is a direct consequence of the mismatch between the crystallographically defined interlayer sites generated within the crystal and the tetrahedral symmetry of the SO 4 2- ions. - Graphical abstract: (a) Observed PXRD pattern of cobalt hydroxytartarate compared with the DIFFaX simulated patterns of (b) 3R 1 and (c) 3R 2 polytypes, respectively

New insights into thorium and uranium oxo-arsenic (III/V) and oxo-phosphates (V) crystal chemistry

Energy Technology Data Exchange (ETDEWEB)

Yu, Na

2015-12-11

The fundamental chemistry of actinides is of great interest owing to the diverse number of valence states and complex coordination chemistry of the actinides. The phases based on actinides and oxo-salt fragments have been under thorough investigation in the last decades. These compounds can be widely found in nature and they affect the migration process of actinides in nature. A better understanding of the fundamental coordination chemistry of actinide compounds with oxo-salts of group V elements is not only important for understanding the actinides behavior within the migration process but can also be used to understand actinide properties in phosphate ceramics. Concerning the radioactive issues, the less radioactive early actinides (i.e. U, Th) can be taken as modeling elements to study the crystal chemistry of the transuranic elements (Np, Pu) without the major handling problems. This can be done as Th(IV) has a very similar coordination chemistry with An(IV) and U(VI) can be chosen as a modeling element for transuranic elements in higher valence states. Therefore, a systematic research on the actinides (U, Th) bearing phases with tetrahedral oxo-anions such as phosphates and arsenates have been performed in this work. High temperature (HT) solid state reaction, High pressure high temperature (HP-HT) solid state reaction and the hydrothermal method were the methods of choice for synthesizing actinide bearing oxo-arsenic(III/V) and oxo- phosphorus(V) phases in the past three years. As a result, numerous novel compounds containing actinides were obtained. The structures of all compounds were determined using single crystal X-ray diffraction data. Raman spectroscopy, EDS, DSC and high temperature powder X-ray diffraction (HT-PXRD) measurements were implemented to characterize the chemical and physical properties of the obtained compounds. The core of this dissertation is a fundamental study of the crystal chemistry of actinides (Th, U) oxo-arsenic (III/V) and oxo

Separation of Co(II) from dilute aqueous solutions by precipitate and adsorbing colloid flotation

International Nuclear Information System (INIS)

Aziz, M.; Benyamin, K.; Shakir, K.; Atomic Energy Establishment, Cairo

1993-01-01

Ion, precipitate and adsorbing colloid flotation of cobalt(II) have been investigated at different pH values, using N-dodecylpyridinium chloride (DPCl). A strong cationic surfactant, and sodium lauryl sulfate (NaLS), a strong anionic surfactant, as collectors. In case of adsorbing colloid flotation, hydrous manganese dioxide was used as an adsorbent. The precipitate flotation curves experimentally obtained with the two tested collectors were compared with the corresponding theoretical one calculated from the data published for Co(II) hydrolysis. The effects of the collector concentration, ageing of the water-MnO 2 -Co(II) system, bubbling time period, cobalt(II) concentration and foreign salts on the percent removal of Co(II) by adsorbing colloid flotation using DPCl as collector were determined. Removals approaching 100% could be achieved under the optimum conditions. (author) 44 refs.; 6 figs

Solid Phase Extraction of Trace Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) Ions in Beverages on Functionalized Polymer Microspheres Prior to Flame Atomic Absorption Spectrometric Determinations.

Science.gov (United States)

Berber, Hale; Alpdogan, Güzin

2017-01-01

In this study, poly(glycidyl methacrylate-methyl methacrylate-divinylbenzene) was synthesized in the form of microspheres, and then functionalized by 2-aminobenzothiazole ligand. The sorption properties of these functionalized microspheres were investigated for separation, preconcentration and determination of Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) ions using flame atomic absorption spectrometry. The optimum pH values for quantitative sorption were 2 - 4, 5 - 8, 6 - 8, 4 - 6, 2 - 6 and 2 - 3 for Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II), respectively, and also the highest sorption capacity of the functionalized microspheres was found to be for Cu(II) with the value of 1.87 mmol g -1 . The detection limits (3σ; N = 6) obtained for the studied metals in the optimal conditions were observed in the range of 0.26 - 2.20 μg L -1 . The proposed method was successfully applied to different beverage samples for the determination of Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) ions, with the relative standard deviation of <3.7%.

Solid phase extraction-inductively coupled plasma spectrometry for adsorption of Co(II) and Ni(II) from radioactive wastewaters by natural and modified zeolites

International Nuclear Information System (INIS)

Akbar Malekpour; Mohammad Edrisi; Shamsollah Shirzadi; Saeed Hajialigol

2011-01-01

Natural and modified clinoptilolite as low-cost adsorbents have been used for adsorption of Co(II) and Ni(II) from nuclear wastewaters both in batch and continuous experiments. Zeolite X was also synthesized and its ability towards the selected cations was examined. Kinetic and thermodynamic behaviors for the process were investigated and adsorption equilibrium was interpreted in term of Langmuir and Freundlich equations. The effect of various parameters including the initial concentration, temperature, ionic strength and pH of solution were examined to achieve the optimized conditions. The clinoptilolite was shown good sorption potential for Co(II) and Ni(II) ions at pH values 4-6. Based on desorption studies, nearly 74 and 85% of adsorbed Co(II) and Ni(II) were removed from clinoptilolite by HCl. The Na + and NH 4 + forms of clinoptilolite were the best modified forms for the removal of investigated cations. It is concluded that the selectivity of clinoptilolite is higher for Co(II) than Ni(II). The synthesized zeolite showed more ability to remove cobalt and nickel ions from aqueous solution than the natural clinoptilolite. The microwave irradiation was found to be more rapid and effective for ion exchange compared to conventional ion exchange process. (author)

Magnetic anisotropy of a Co-II single ion magnet with distorted trigonal prismatic coordination

DEFF Research Database (Denmark)

Peng, Yan; Bodenstein, Tilmann; Fink, Karin

2016-01-01

calculations. Though the complex shows a slight deviation from an ideal trigonal prismatic coordination, the zero-field splitting as well as the g-tensor are strongly axial with D = -41 cm(-1) and E ... with a spin Hamiltonian of the form H = D(S-z(2) - S(S + 1)/3) + E(S-x(2) - S-y(2)) + mu(B)gS.B using an effective spin S = 3/2. Calculations on model complexes show the influence of the coordinating atoms and the deviation from the ideal trigonal prismatic coordination. As the distortion is reduced towards...... idealised D-3h, the zero field splitting increases and the g-tensor of the second Kramers doublet also becomes axial....

Coordination behavior of tetraaza [N4] ligand towards Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes: Synthesis, spectroscopic characterization and anticancer activity

Science.gov (United States)

El-Boraey, Hanaa A.

2012-11-01

Novel eight Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes with [N4] ligand (L) i.e. 2-amino-N-{2-[(2-aminobenzoyl)amino]ethyl}benzamide have been synthesized and structurally characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and molar conductivity measurements. On the basis of IR, mass, electronic and EPR spectral studies an octahedral geometry has been proposed for Co(II), Ni(II) complexes and Cu(II) chloride complex, square-pyramidal for Cu(I) bromide complex. For Cu(II) nitrate complex (6), Pd(II) complex (8) square planar geometry was proposed. The EPR data of Cu(II) complexes in powdered form indicate dx2-y2 ground state of Cu(II) ion. The antitumor activity of the synthesized ligand and some selected metal complexes has been studied. The palladium(II) complex (8) was found to display cytotoxicity (IC50 = 25.6 and 41 μM) against human breast cancer cell line MCF-7 and human hepatocarcinoma HEPG2 cell line.

Synthesis, spectroscopic characterization and antimicrobial activity evaluation of new tridentate Schiff bases and their Co(II complexes

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Ganesh More

2017-12-01

Full Text Available A series of Schiff base tridentate ligands and their respective Co(II complexes have been synthesized and characterized by elemental analysis, magnetic susceptibility, IR, NMR and UV–Visible spectra, thermal studies. The IR spectral data suggested that all the ligands acted as monobasic tridentate towards central Co(II ion with an ONO donor atoms sequentially. Analytical data and magnetic susceptibility revealed 1:2 metal to ligand stoichiometry and octahedral geometry for all Co(II complexes. All the prepared compounds were also screened for antimicrobial activity against 5 ESBL (Extended Spectrum β-lactamase and 5 MBL (Metallo β-lactamase producing uropathogens and for antitubercular activity against Mycobacterium tuberculosis (H37Rv strain. Keywords: Schiff base, Antitubercular, Antimicrobial, ESBL, MBL, Metal complex, o-hydroxyl aldehyde, Aminothiophene

Bioinspired catalytic generation of high-valent cobalt-oxo species by the axially coordinated CoPc on pyridine-functionalized MWCNTs for the elimination of organic contaminants

Science.gov (United States)

Li, Nan; Wang, Ying; Wu, Chenren; Lu, Wangyang; Pei, Kemei; Chen, Wenxing

2018-03-01

Enzymes have always been a source of inspiration for the design and improvement of catalysts. Many examples are occurring in heme/non-heme metalloenzymes with the generation of active high-valent metal-oxo intermediates that are controlled by the surrounding amino acids/protein and axial residue ligands, facilitating the efficient oxidation of substrates in biochemical processes. Here, the high-valent cobalt-oxo species have been formed during the heterolysis of H2O2 activated by the bioinspired catalyst, axially coordinated cobalt phthalocyanine (CoPc) on pyridine-functionalized multi-walled carbon nanotubes (MWCNTs-Py), characterized by ultraviolet-visible and X-ray photoelectron spectroscopy. Formation process of the active cobalt-oxo species has been further confirmed by electrospray ionization mass spectrometry analysis and the results from the density functional theory (B3LYP/6-311G) calculations. Such high-valent cobalt-oxo species exhibit high reactivity and enough persistence for the oxidation of the target substrate, C.I. Acid Red 1. The oxidation products are nearly biodegradable small molecules identified by ultra-performance liquid chromatography/high-definition mass spectrometry. This strategy provides a foundation on developing efficient and persistent catalytic system, in particular oxidation processes based on the complex catalysts with N4 macrocycle structures.

A multi-functional coordination polymer coexisting spontaneous chirality resolution and weak ferromagnetism

Energy Technology Data Exchange (ETDEWEB)

Li, Xiu-Hua, E-mail: xhli.univ@gmail.com [College of Chemistry and Chemical Engineering, Fujian Normal University, Fuzhou, 350117 Fujian (China); Zhang, Qi [School of Life Science, Changchun Normal University, Changchun, 130032 Jilin (China); Hu, Ping [Southampton Management School, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

2014-10-15

A multifunctional homochiral coordination polymer, [Co(H{sub 2}O)(BDC)(4,4′-BPY)]∙3H{sub 2}O (1) (H{sub 2}BDC=1,2-benzenedicarboxylate and 4,4′-BPY=4,4′-bipyridine), has been successfully isolated from Co(II) ions and mixed ligands (1,2-benzenedicarboxylate and 4,4′-bipyridine). Complex 1, which exhibits spontaneous chirality resolution and weak ferromagnetism, is built by chiral helices interconnected via end-to-end 4,4′-BPY bridges into a two-dimensional (2D) layer structure. - Graphical abstract: A 2D cobalt coordination polymer compound showing spontaneous chirality resolution and weak ferromagnetism. - Highlights: • A new 2D cobalt mix-ligand coordination polymer complex has been synthesized. • The cobalt coordination polymer complex shows spontaneous chirality resolution in solid state. • The cobalt coordination polymer complex displays dominant and weak intrachain ferromagnetic interactions.

A multi-functional coordination polymer coexisting spontaneous chirality resolution and weak ferromagnetism

International Nuclear Information System (INIS)

Li, Xiu-Hua; Zhang, Qi; Hu, Ping

2014-01-01

A multifunctional homochiral coordination polymer, [Co(H 2 O)(BDC)(4,4′-BPY)]∙3H 2 O (1) (H 2 BDC=1,2-benzenedicarboxylate and 4,4′-BPY=4,4′-bipyridine), has been successfully isolated from Co(II) ions and mixed ligands (1,2-benzenedicarboxylate and 4,4′-bipyridine). Complex 1, which exhibits spontaneous chirality resolution and weak ferromagnetism, is built by chiral helices interconnected via end-to-end 4,4′-BPY bridges into a two-dimensional (2D) layer structure. - Graphical abstract: A 2D cobalt coordination polymer compound showing spontaneous chirality resolution and weak ferromagnetism. - Highlights: • A new 2D cobalt mix-ligand coordination polymer complex has been synthesized. • The cobalt coordination polymer complex shows spontaneous chirality resolution in solid state. • The cobalt coordination polymer complex displays dominant and weak intrachain ferromagnetic interactions

Removal of cobalt ions from aqueous solution by an amination graphene oxide nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Fang, Fang [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000 (China); Kong, Lingtao, E-mail: ltkong@iim.ac.cn [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Jiarui [College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241000 (China); Wu, Shibiao [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); School of Chemistry and Chemical Engineering, Anhui University, Hefei, Anhui 230039 (China); Zhang, Kaisheng [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Wang, Xuelong [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); School of Chemistry and Chemical Engineering, Anhui University, Hefei, Anhui 230039 (China); Sun, Bai; Jin, Zhen; Wang, Jin [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Xing-Jiu, E-mail: xjhuang@iim.ac.cn [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Liu, Jinhuai, E-mail: jhliu@iim.ac.cn [Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

2014-04-01

Highlights: • A newly designed GO-NH{sub 2}: Higher adsorption capability than that of activated carbon. • Very quick adsorption property: More than 90% of Co(II) can be removed within 5 min. • One of the highest adsorption capabilities of today's nanomaterials for Co(II) (116.35 mg/g). • GO-NH{sub 2} membrane can remove more than 98% Co(II) from the water. - Abstract: A newly designed amination graphene oxide (GO-NH{sub 2}), a superior adsorption capability to that of activated carbon, was fabricated by graphene oxide (GO) combining with aromatic diazonium salt. The resultant GO-NH{sub 2} maintained a high surface area of 320 m{sup 2}/g. When used as an adsorbent, the GO-NH{sub 2} demonstrated a very quick adsorption property for the removal of Co(II) ions, more than 90% of Co(II) ions could be removed within 5 min for dilute solutions at 0.3 g/L adsorbent dose. The adsorption capability approaches 116.35 mg/g, which is one of the highest capabilities of today's materials. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that the Co(II) ions adsorption on GO-NH{sub 2} was a spontaneous process. Considering the superior adsorption capability, the GO-NH{sub 2} filter membrane was fabricated for the removal of Co(II) ions. Membrane filtration experiments revealed that the removal capabilities of the materials for cobalt ions depended on the membrane's thickness, flow rate and initial concentration of Co(II) ions. The highest percentage removal of Co(II) exceeds 98%, indicating that the GO-NH{sub 2} is one of the very suitable membrane materials in environmental pollution management.

Syntheses, structures, and photoluminescence of lanthanide coordination polymers based on 4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid

Energy Technology Data Exchange (ETDEWEB)

Qian, Jing; Li, Lei; Peng, Jing-Wei; Qiao, Wei-Wei; Sun, Mei-Mei [College of Chemistry, Tianjin Normal University, Tianjin (China); Gu, Wen [College of Chemistry, Nankai University, Tianjin (China)

2018-03-15

Investigating the coordination chemistry of H{sub 2}CDA (4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid) with rare earth salts Ln(NO{sub 3}){sub 3} under hydrothermal conditions, structure transformation phenomenon was observed. The ligand, H{sub 2}CDA charged to its position isomer, enol type structure, H{sub 3}CAM (4-hydroxypyridine-2,6-dicarboxylic acid). Six new lanthanide(III) coordination polymers with the formulas [Ln(CAM)(H{sub 2}O){sub 3}]{sub n} [Ln = La (1), Pr, (2)] and {[Ln(CAM)(H_2O)_3].H_2O}{sub n} [Ln = Nd, (3), Sm, (4), Eu, (5), Y, (6)] were synthesized and characterized. The X-ray structure analyses show two kinds of coordination structures. The complexes 1 and 2 and 3-6 are isostructural. Complexes 1 and 2 crystallize in the monoclinic C{sub 2}/c space group, whereas 3-6 crystallize in the monoclinic system with space group P2{sub 1}/n. In the two kinds of structures, H{sub 3}CAM displays two different coordination modes. The Sm{sup III} and Eu{sup III} complexes exhibit the corresponding characteristic luminescence in the visible region at an excitation of 376 nm. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synergistic complexes of uranyl ion with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 and some oxo-donors

International Nuclear Information System (INIS)

Nagar, M.S.; Ruikar, P.B.; Subramanian, M.S.

1987-01-01

Complexes of uranyl ion with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5(PMAP) and various oxo-donors such as aliphatic sulphoxides [R 2 SO, where R = i-C 5 H 11 (DISO), n-C 6 H 13 (DHSO), n-C 7 H 15 (DSSO), n-C 8 H 17 (DOSO), n-C 9 H 19 (DNSO), n-C 10 H 21 (DDSO), n-C 11 H 23 (DUDSO) and n-C 4 H 9 (DBUSO)] tributylphosphate (TBP) and tri-n-octyl phosphine oxide (TOPO) have been synthesised and characterized. Analytical data establish that they have the stoichiometry UO 2 (PMAP) 2 X where X is the oxo-donor. The IR spectra of the sulphoxide complexes in the S - O stretching region indicate that the ligands R 2 SO are O-bonded. The methyl protons of the pyrazole ring and acetyl group in the PMAP ligand are equivalent giving rise to a single sharp peak in the PMR spectra, whereas in the synergistic complexes with the oxo-donors, two deshielded peaks of equal intensity are observed which indicate the non-equivalence of the methyl groups. The peak which is more deshielded has been ascribed to the methyl of the acetyl group. The higher deshielding of these methyl protons arises due to the transfer of electron density to the metal atom on complexation. (author)

Recovery of Cd(II), Co(II) and Ni(II) from Chloride Medium by Solvent Extraction Using CYANEX 923 and CYANEX 272 I

International Nuclear Information System (INIS)

Ahmed, M.; El Dessouky, S.I.; El-Nadi, Y.A.; Daoud, J.A.; Saad, E.A.

2008-01-01

The paper aims to study the extraction and separation of Cd(II), Co(II) and Ni(II) from their mixtures in hydrochloric acid medium with CYANEX 923 in kerosene. Preliminary investigations showed that only Cd(II) is extracted with CYANEX 923 while Co(II) and Ni(II) are not extracted. Different parameters affecting the extraction of Cd(II) with CYANEX 923 such as hydrochloric acid, hydrogen ion, extractant and metal concentrations, temperature investigations were also investigated. The stoichiometry of the extracted metal species investigated was found to be HCdCl 3 . 2 CYANEX 923. The stripping of the extracted Cd(II) species is obtained with 0.1 M HCl solution. Co(II) was found to be extracted with CYANEX 272 at ph 5.8 leaving Ni(II) in the solution. A developed process for the sequential of Cd(II), Co(II) and Ni(II) from their mixture in hydrochloric acid medium is proposed

Crystal structure of catena-poly[[aqua(2,2′:6′,2′′-terpyridine-κ3N,N′,N′′cobalt(II]-μ-cyanido-κ2N:C-[dicyanidoplatinum(II]-μ-cyanido-κ2C:N

Directory of Open Access Journals (Sweden)

Frankie White

2014-09-01

Full Text Available The title compound, [Co(C15H11N3(H2O{Pt(CN4}]n, is a one-dimensional coordination polymer formed under hydrothermal reaction conditions. The CoII site has sixfold coordination with a distorted octahedral geometry, while the PtII ion is coordinated by four cyanide groups in an almost regular square-planar geometry. The compound contains twofold rotation symmetry about its CoII ion, the water molecule and the terpyridine ligand, and the PtII atom resides on an inversion center. trans-Bridging by the tetracyanidoplatinate(II anions links the CoII cations, forming chains parallel to [-101]. Additionally, each CoII atom is coordinated by one water molecule and one tridentate 2,2′:6′,2′′-terpyridine ligand. O—H...N hydrogen-bonding interactions are found between adjacent chains and help to consolidate the crystal packing. In addition, relatively weak π–π stacking interactions exist between the terpyridine ligands of adjacent chains [interplanar distance = 3.464 (7 Å]. No Pt...Pt interactions are observed in the structure.

Sulfur K-edge X-ray absorption spectroscopy and density functional theory calculations on monooxo Mo(IV) and bisoxo Mo(VI) bis-dithiolenes: insights into the mechanism of oxo transfer in sulfite oxidase and its relation to the mechanism of DMSO reductase.

Science.gov (United States)

Ha, Yang; Tenderholt, Adam L; Holm, Richard H; Hedman, Britt; Hodgson, Keith O; Solomon, Edward I

2014-06-25

Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations have been used to determine the electronic structures of two complexes [Mo(IV)O(bdt)2](2-) and [Mo(VI)O2(bdt)2](2-) (bdt = benzene-1,2-dithiolate(2-)) that relate to the reduced and oxidized forms of sulfite oxidase (SO). These are compared with those of previously studied dimethyl sulfoxide reductase (DMSOr) models. DFT calculations supported by the data are extended to evaluate the reaction coordinate for oxo transfer to a phosphite ester substrate. Three possible transition states are found with the one at lowest energy, stabilized by a P-S interaction, in good agreement with experimental kinetics data. Comparison of both oxo transfer reactions shows that in DMSOr, where the oxo is transferred from the substrate to the metal ion, the oxo transfer induces electron transfer, while in SO, where the oxo transfer is from the metal site to the substrate, the electron transfer initiates oxo transfer. This difference in reactivity is related to the difference in frontier molecular orbitals (FMO) of the metal-oxo and substrate-oxo bonds. Finally, these experimentally related calculations are extended to oxo transfer by sulfite oxidase. The presence of only one dithiolene at the enzyme active site selectively activates the equatorial oxo for transfer, and allows facile structural reorganization during turnover.

Temperature-controlled two new Co(II) compounds with distinct topological networks: Syntheses, crystal structures and catalytic properties

Science.gov (United States)

Meng, Qing-Hua; Long, Xu; Liu, Jing-Li; Zhang, Shuan; Zhang, Guang-Hui

2018-04-01

Two new Co(II) coordination compounds, namely [Co2(bptc)(bpp)2]n (1) and [Co(bptc)0.5(bpp)]n (2) (H4bptc = biphenyl-3,3‧,5,5‧-tetracarboxylic acid, bpp = 1,3-di(4-pyridyl)propane), have been hydrothermally synthesized from the same reactants via tuning the reaction temperature. Single crystal X-ray diffraction analyses revealed that both 1 and 2 feature 2D sheet motifs. Topological analyses revealed that compounds 1 and 2 show distinct topological networks. Under the weak Van der Waals interactions, the 2D sheet motifs of compounds 1 and 2 are further packed into 2D→3D interdigitated supramolecular frameworks. Moreover, the two Co(II) compounds show high catalytic activities for degradation of methyl orange (MO) in a Fenten-like process.

Syntheses and structures of technetium(V) and rhenium(V) oxo complexes of peptide having KYC-sequence

International Nuclear Information System (INIS)

Takayama, T.; Suzuki, K.; Sekine, T.; Kudo, H.

2000-01-01

Technetium(V) and rhenium(V) oxo complexes of a peptide having a KYC-sequence such as KYCAR (H 3 L 5 ) and KYCAREPPTRTNAYQGQG-NH 2 (H 3 L 18 ) were synthesized, and structures of the complexes were characterized by spectroscopic techniques. All of the complexes were synthesized by the ligand exchange reaction of [(n-C 4 H 9 ) 4 N][MOCl 4 ] (M = 99 Tc, Re) with peptide in methanol or dimethylformamide solution. These complexes have a square pyramidal structure with an oxo ligand at the apical position. The peptide is coordinated to a metal atom through N amine of lysine. S thiol of cysteine, and N amide of tyrosine and cysteine in the equatorial plane. A lysine (CH 2 ) 4 NH 2 group of the L 5 ligand has the syn conformation with respect to metal-oxo bonding in the complex. The syn isomer was selectively formed in the ligand exchange reaction. The conversion of the syn isomer to the anti isomer was observed only for syn-[ReO(L 5 )], in which the coordination of water to the trans position of the oxo ligand was involved. (orig.)

Boletus edulis loaded with γ-Fe2O3 nanoparticles as a magnetic sorbent for preconcentration of Co(II) and Sn(II) prior to their determination by ICP-OES.

Science.gov (United States)

Ozdemir, Sadin; Serkan Yalcin, M; Kilinc, Ersin; Soylak, Mustafa

2017-12-20

The authors show that the fungus Boletus edulis loaded with γ-Fe 2 O 3 nanoparticles is a viable sorbent for magnetic solid phase extraction of trace levels of Co(II) and Sn(II). The surface structure of immobilized magnetized B. edulis was characterized by FT-IR, SEM and EDX. Experimental parameters were optimized. Following elution with 1 M HCl, the ions were quantified by ICP-OES. The limits of detection are 21 pg·mL -1 for Co(II), and 19 pg·mL -1 for Sn(II). The preconcentration factors are 100 for both ions. The sorption capacities of the sorbent are 35.8 mg·g -1 for Co(II) and 29.6 mg·g -1 for Sn(II). The method was applied to the analysis of certificated reference materials and gave ≥95% recoveries with low RSDs. It was also successfully applied to the quantification of Co(II) and Sn(II) in spiked environmental and food samples. Graphical abstract The fungus Boletus edulis loaded with γ-Fe 2 O 3 nanoparticles is a viable biosorbent for magnetic solid phase extraction (MSPE) of trace levels of Co(II) and Sn(II). The surface structure of immobilized magnetized B. edulis was characterized by FT-IR, SEM and EDX. Experimental parameters were optimized.

Coordination Polymers of N, Nʼ-di-(8-Hydroxyquinolinolyl- 5-methyl-N, N-diethyl-1,3-propane diamine (QEPD

Directory of Open Access Journals (Sweden)

Asha D. Patel

2010-01-01

Full Text Available Coordination polymers containing a novel bis(oxine bidentate ligand, namely N,Nʼ-di(8-hydroxyquinolinolyl-5-methyl-N,Nʼ-diethyl-1,3-propane diamine (QEPD have been prepared with the metal ions Zn(II, Cu(II, Ni(II, Co(II and Mn(II. The novel bis-(bidentate ligand was synthesized by condensation of 5-chloromethyl-8-hydroxyquinoline hydrochloride with N,Nʼ-diethyl-1,2- propane diamine in the presence of a base catalyses. All of these coordination polymers and the parent ligand were characterized by elemental analyses, IR spectral and diffuse reflectance spectral studies. The thermal stability and number- average molecular weights (Mn¯ of all of the coordination polymers were determined by thermogravimetric analyses and non-aqueous conductometric titrations, respectively. In addition, all of the coordination polymers have been characterized by their magnetic susceptibilities.

Oxidation of cyclohexane catalyzed by metal-ion-exchanged zeolites.

Science.gov (United States)

Sökmen, Ilkay; Sevin, Fatma

2003-08-01

The ion-exchange rates and capacities of the zeolite NaY for the Cu(II), Co(II), and Pb(II) metal ions were investigated. Ion-exchange equilibria were achieved in approximately 72 h for all the metal ions. The maximum ion exchange of metal ions into the zeolite was found to be 120 mg Pb(II), 110 mg Cu(II), and 100 mg Co(II) per gram of zeolite NaY. It is observed that the exchange capacity of a zeolite varies with the exchanged metal ion and the amount of metal ions exchanged into zeolite decreases in the sequence Pb(II) > Cu(II) > Co(II). Application of the metal-ion-exchanged zeolites in oxidation of cyclohexane in liquid phase with visible light was examined and it is observed that the order of reactivity of the zeolites for the conversion of cyclohexane to cyclohexanone and cyclohexanol is CuY > CoY > PbY. It is found that conversion increases by increase of the empty active sites of a zeolite and the formation of cyclohexanol is favored initially, but the cyclohexanol is subsequently converted to cyclohexanone.

Removal of Co(II) from waste water using dry cow dung powder : a green ambrosia to soil

Science.gov (United States)

Bagla, Hemlata; Khilnani, Roshan

2015-04-01

Co(II) is one of the hazardous products found in the waste streams. The anthropogenic activities are major sources of Co(II) in our environment. Some of the well-established processes such as chemical precipitation, membrane process, liquid extraction and ion exchange have been applied as a tool for the removal of this metal ion [1]. All the above methods are not considered to be greener due to some of their shortcomings such as incomplete metal ion removal, high requirement of energy and reagents, generation of toxic sludge or other waste materials which in turn require further treatments for their cautious disposal. The present investigation entails the application of dry cow dung powder (DCP) as an indigenous, inexpensive and eco-friendly material for the removal of Co(II) from aqueous medium. DCP, is naturally available bio-organic, complex, polymorphic humified fecal matter of cow and is enriched with minerals, carbohydrates, fats, proteins, bile pigments, aliphatic-aromatic species such as 'Humic acid' (HA), Fulvic acid, Ulmic acid [2,3]. Batch biosorption experiments were conducted employing 60Co(II) as a tracer and effect of various process parameters such as pH (1-8), temperature (283-363K), amount of biosorbent (5-40 g/L), time of equilibration (0-30 min), agitation speed (0-4000 rpm), concentration of initial metal ions (0.5-20 mg/mL) and interfering effect of different organic as well as inorganic salts were studied. The Kinetic studies were carried out employing various models but the best fitting was given by Lagergren Pseudo-second order model [4] with high correlation coefficient R2 value of 0.999 and adsorption capacity of 2.31 mg/g. The thermodynamic parameters for biosorption were also evaluated which indicated spontaneous and exothermic process with high affinity of DCP for Co(II). Many naturally available materials are used for biosorption of hazardous metal pollutants, where most of them are physically or chemically modified. In this research

Syntheses and structures of technetium(V) and rhenium(V) oxo complexes of peptide having KYC-sequence

Energy Technology Data Exchange (ETDEWEB)

Takayama, T.; Suzuki, K.; Sekine, T.; Kudo, H. [Dept. of Chemistry, Tohoku Univ., Sendai (Japan)

2000-07-01

Technetium(V) and rhenium(V) oxo complexes of a peptide having a KYC-sequence such as KYCAR (H{sub 3}L{sup 5}) and KYCAREPPTRTNAYQGQG-NH{sub 2} (H{sub 3}L{sup 18}) were synthesized, and structures of the complexes were characterized by spectroscopic techniques. All of the complexes were synthesized by the ligand exchange reaction of [(n-C{sub 4}H{sub 9}){sub 4}N][MOCl{sub 4}] (M = {sup 99}Tc, Re) with peptide in methanol or dimethylformamide solution. These complexes have a square pyramidal structure with an oxo ligand at the apical position. The peptide is coordinated to a metal atom through N{sub amine} of lysine. S{sub thiol} of cysteine, and N{sub amide} of tyrosine and cysteine in the equatorial plane. A lysine (CH{sub 2}){sub 4}NH{sub 2} group of the L{sup 5} ligand has the syn conformation with respect to metal-oxo bonding in the complex. The syn isomer was selectively formed in the ligand exchange reaction. The conversion of the syn isomer to the anti isomer was observed only for syn-[ReO(L{sup 5})], in which the coordination of water to the trans position of the oxo ligand was involved. (orig.)

Spectroscopic evaluation of Co(II), Ni(II) and Cu(II) complexes derived from thiosemicarbazone and semicarbazone

Science.gov (United States)

Chandra, Sulekh; Kumar, Anil

2007-12-01

Co(II), Ni(II) and Cu(II) complexes were synthesized with thiosemicarbazone (L 1) and semicarbazone (L 2) derived from 2-acetyl furan. These complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non-electrolytic nature. All the complexes are of high-spin type. On the basis of different spectral studies six coordinated geometry may be assigned for all the complexes except Co(L) 2(SO 4) and Cu(L) 2(SO 4) [where L = L 1 and L 2] which are of five coordinated square pyramidal geometry.

Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II, Co(II, Ni(II, Cu(II, and Zn(II] metals

Directory of Open Access Journals (Sweden)

Nahid Nishat

2016-09-01

Full Text Available A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II, Co(II, Ni(II, Cu(II and Zn(II. All the polymeric compounds were characterized by (FT-IR spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA and antibacterial activities. Polymer complexes of Mn(II, Co(II and Ni(II show octahedral geometry, while polymer complexes of Cu(II and Zn(II show square planar and tetrahedral geometry, respectively. The TGA revealed that all the polymer metal complexes are more thermally stable than their parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM-D-5338-93 standards of biodegradable polymers by CO2 evolution method which says that coordination decreases biodegradability. The antibacterial activity was screened with the agar well diffusion method against some selected microorganisms. Among all the complexes, the antibacterial activity of the Cu(II polymer–metal complex showed the highest zone of inhibition because of its higher stability constant.

Electron Spin Resonance Studies of Carbonic Anhydrase: Transition Metal Ions and Spin-Labeled Sulfonamides*

Science.gov (United States)

Taylor, June S.; Mushak, Paul; Coleman, Joseph E.

1970-01-01

Electron spin resonance (esr) spectra of Cu(II) and Co(II) carbonic anhydrase, and a spin-labeled sulfonamide complex of the Zn(II) enzyme, are reported. The coordination geometry of Cu(II) bound in the enzyme appears to have approximately axial symmetry. Esr spectra of enzyme complexes with metal-binding anions also show axial symmetry and greater covalency, in the order ethoxzolamide cyanide complex suggests the presence of two, and probably three, equivalent nitrogen ligands from the protein. Esr spectra of the Co(II) enzyme and its complexes show two types of Co(II) environment, one typical of the native enzyme and the 1:1 CN- complex, and one typical of a 2:1 CN- complex. Co(II) in the 2:1 complex appears to be low-spin and probably has a coordination number of 5. Binding of a spin-labeled sulfonamide to the active center immobilizes the free radical. The similarity of the esr spectra of spin-labeled Zn(II) and Co(II) carbonic anhydrases suggests that the conformation at the active center is similar in the two metal derivatives. PMID:4320976

Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS)

Energy Technology Data Exchange (ETDEWEB)

Duran, Celal [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Art and Science, Karadeniz Technical University, 28049 Giresun (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Art and Science, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Art and Science, Pamukkale University, 20020 Denizli (Turkey); Sentuerk, Hasan Basri [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuefekci, Mehmet [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

2007-07-19

A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L{sup -1} HNO{sub 3} in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 {mu}g L{sup -1}. The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

Influence of differences in resin-matrix structure on ion-exchange adsorption of trace amounts of Ag(I), Co(II) and Cr(III)

International Nuclear Information System (INIS)

Matsuzuru, Hideo; Wadachi, Yoshiki

1975-01-01

The influence of differences in resin-matrix structure on the ion-exchange adsorption of trace amounts of Ag(I), Co(II) and Cr(III) was studied by using both macroreticular and gel-type resins. The results indicate that the rate-determining step of the exchange mechanism of these ions is film diffusion under conditions of finite volume and at an ionic strengh of 1x10 -4 . The diffusion coefficient decreases with increasing size of the hydrated ions - in the order Dsub(Ag)>Dsub(Co)>Dsub(Cr). It may be said that the faster rate of exchange in the macroreticular resin is due to the larger surface area and pore size of this resin. Also, in a column system - as opposed to batch operation, it is assumed that the rate-determining step of the exchange reaction is film diffusion. With both resins, the kinetic coefficient β decreases in the order: βsub(Ag)>βsub(Co)>βsub(Cr). For the same linear velocity, a higher β-value is obtained with the macroreticular than with the gel-type resin. Consequently, a higher separating efficiency may be expected from the macroreticular resin for concentrating and separating trace amounts of cations from aqueous solution. (auth.)

Structure, magnetism, and theoretical study of a mixed-valence Co(II)3Co(III)4 heptanuclear wheel: lack of SMM behavior despite negative magnetic anisotropy.

Science.gov (United States)

Chibotaru, Liviu F; Ungur, Liviu; Aronica, Christophe; Elmoll, Hani; Pilet, Guillaume; Luneau, Dominique

2008-09-17

A mixed-valence Co(II)/Co(III) heptanuclear wheel [Co(II)3Co(III)4(L)6(MeO)6] (LH2 = 1,1,1-trifluoro-7-hydroxy-4-methyl-5-aza-hept-3-en-2-one) has been synthesized and its crystal structure determined using single-crystal X-ray diffraction. The valence state of each cobalt ion was established by bond valence sum calculations. Studies of the temperature dependence of the magnetic susceptibility and the field dependence of the magnetization evidence ferromagnetic interactions within the compound. In order to understand the magnetic properties of this Co7 wheel, we performed ab initio calculations for each cobalt fragment at the CASSCF/CASPT2 level, including spin-orbit coupling effects within the SO-RASSI approach. The four Co(III) ions were found to be diamagnetic and to give a significant temperature-independent paramagnetic contribution to the susceptibility. The spin-orbit coupling on the three Co(II) sites leads to separations of approximately 200 cm(-1) between the ground and excited Kramers doublets, placing the Co7 wheel into a weak-exchange limit in which the lowest electronic states are adequately described by the anisotropic exchange interaction between the lowest Kramers doublets on Co(II) sites. Simulation of the exchange interaction was done within the Lines model, keeping the fully ab initio treatment of magnetic anisotropy effects on individual cobalt fragments using a recently developed methodology. A good description of the susceptibility and magnetization was obtained for nearest-neighbor (J1) and next-nearest-neighbor (J2) exchange parameters (1.5 and 5.5 cm(-1), respectively). The strong ferromagnetic interaction between distant cobalt ions arises as a result of low electron-promotion energies in the exchange bridges containing Co(III) ions. The calculations showed a large value of the magnetization along the main magnetic axis (10.1 mu(B)), which is a combined effect of the ferromagnetic exchange interaction and negative magnetic anisotropy on

Titanium coordination compounds: from discrete metal complexes to metal–organic frameworks

KAUST Repository

Assi, Hala

2017-05-24

Owing to their promise in photocatalysis and optoelectronics, titanium based metal–organic frameworks (MOFs) are one of the most appealing classes of MOFs reported to date. Nevertheless, Ti-MOFs are still very scarce because of their challenging synthesis associated with a poor degree of control of their chemistry and crystallization. This review aims at giving an overview of the recent progress in this field focusing on the most relevant existing titanium coordination compounds as well as their promising photoredox properties. Not only Ti-MOFs but also Ti-oxo-clusters will be discussed and particular interest will be dedicated to highlight the different successful synthetic strategies allowing to overcome the still “unpredictable” reactivity of titanium ions, particularly to afford crystalline porous coordination polymers.

Synthesis, characterization, and reactivity of a uranium(VI) carbene imido oxo complex

Energy Technology Data Exchange (ETDEWEB)

Lu, Erli; Cooper, Oliver J.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [Nottingham Univ. (United Kingdom). School of Chemistry; Tuna, Floriana; McInnes, Eric J.L. [Manchester Univ. (United Kingdom). School of Chemistry and Photon Science Inst.

2014-06-23

We report the uranium(VI) carbene imido oxo complex [U(BIPM{sup TMS})(NMes)(O)(DMAP){sub 2}] (5, BIPM{sup TMS}=C(PPh{sub 2}NSiMe{sub 3}){sub 2}; Mes=2,4,6-Me{sub 3}C{sub 6}H{sub 2}; DMAP=4-(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two-electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T-shaped motif with respect to the carbene, which is consistent with an inverse trans-influence. Complex 5 reacts with tert-butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPM{sup TMS})(O){sub 2}(DMAP){sub 2}] (6).

Electrochemically Generated cis-Carboxylato-Coordinated Iron(IV) Oxo Acid-Base Congeners as Promiscuous Oxidants of Water Pollutants

DEFF Research Database (Denmark)

de Sousa, David P; Miller, Christopher J; Chang, Yingyue

2017-01-01

The nonheme iron(IV) oxo complex [FeIV(O)(tpenaH)]2+ and its conjugate base [FeIV(O)(tpena)]+ [tpena- = N,N,N'-tris(2-pyridylmethyl)ethylenediamine-N'-acetate] have been prepared electrochemically in water by bulk electrolysis of solutions prepared from [FeIII2(μ-O)(tpenaH)2](ClO4)4 at potentials...... of the electrochemically generated iron(IV) oxo complexes, in terms of the broad range of substrates examined, represents an important step toward the goal of cost-effective electrocatalytic water purification....

Synthesis, characterization, X-ray crystal structure and conductometry studying of a number of new Schiff base complexes; a new example of binuclear square pyramidal geometry of Cu(II) complex bridged with an oxo group

Science.gov (United States)

Golbedaghi, Reza; Alavipour, Ehsan

2015-11-01

Three new binuclear Cu(II), Mn(II), Co(II) complexes [Cu2(L) (ClO4)](ClO4)2 (1), [Mn2(L) (ClO4)](ClO4)2 (2), and [Co2(L) (ClO4)](ClO4)2 (3), {L = 1,3-bis(2-((Z)-(2-aminopropylimino)methyl)phenoxy)propan-2-ol} have been synthesized. Single crystal X-ray structure analysis of complex 1 showed that the complex is binuclear and all nitrogen and oxygen atoms of ligand (N4O3) are coordinated to two Cu(II) center ions. In addition, the crystal structure studying shows, a perchlorate ion has been bridged to the Cu(II) metal centers. However, two distorted square pyramidal Cu(II) ions are bridged asymmetrically by a perchlorate ion and oxygen of hydroxyl group of Schiff base ligand. In addition, the conductometry behaviors of all complexes were studied in acetonitrile solution.

Metals in proteins: correlation between the metal-ion type, coordination number and the amino-acid residues involved in the coordination.

Science.gov (United States)

Dokmanić, Ivan; Sikić, Mile; Tomić, Sanja

2008-03-01

Metal ions are constituents of many metalloproteins, in which they have either catalytic (metalloenzymes) or structural functions. In this work, the characteristics of various metals were studied (Cu, Zn, Mg, Mn, Fe, Co, Ni, Cd and Ca in proteins with known crystal structure) as well as the specificity of their environments. The analysis was performed on two data sets: the set of protein structures in the Protein Data Bank (PDB) determined with resolution metal ion and its electron donors and the latter was used to assess the preferred coordination numbers and common combinations of amino-acid residues in the neighbourhood of each metal. Although the metal ions considered predominantly had a valence of two, their preferred coordination number and the type of amino-acid residues that participate in the coordination differed significantly from one metal ion to the next. This study concentrates on finding the specificities of a metal-ion environment, namely the distribution of coordination numbers and the amino-acid residue types that frequently take part in coordination. Furthermore, the correlation between the coordination number and the occurrence of certain amino-acid residues (quartets and triplets) in a metal-ion coordination sphere was analysed. The results obtained are of particular value for the identification and modelling of metal-binding sites in protein structures derived by homology modelling. Knowledge of the geometry and characteristics of the metal-binding sites in metalloproteins of known function can help to more closely determine the biological activity of proteins of unknown function and to aid in design of proteins with specific affinity for certain metals.

Sugar-metal ion interactions: The coordination behavior of cesium ion with lactose, D-arabinose and L-arabinose

Science.gov (United States)

Jiang, Ye; Xue, Junhui; Wen, Xiaodong; Zhai, Yanjun; Yang, Limin; Xu, Yizhuang; Zhao, Guozhong; Kou, Kuan; Liu, Kexin; Chen, Jia'er; Wu, Jinguang

2016-04-01

The novel cesium chloride-lactose complex (CsCl·C12H22O10 (Cs-Lac), cesium chloride-D-arabinose and L-arabinose complexes (CsCl·C5H10O5, Cs-D-Ara and Cs-L-Ara) have been synthesized and characterized using X-ray diffraction, FTIR, FIR, THz and Raman spectroscopies. Cs+ is 9-coordinated to two chloride ions and seven hydroxyl groups from five lactose molecules in Cs-Lac. In the structures of CsCl-D-arabinose and CsCl-L-arabinose complexes, two kinds of Cs+ ions coexist in the structures. Cs1 is 10-coordinated with two chloride ions and eight hydroxyl groups from five arabinose molecule; Cs2 is 9-coordinated to three chloride ions and six hydroxyl groups from five arabinose molecules. Two coordination modes of arabinose coexist in the structures. α-D-arabinopyranose and α-L-arabinopyranose appear in the structures of Cs-D-Ara and Cs-L-Ara complexes. FTIR and Raman results indicate variations of hydrogen bonds and the conformation of the ligands after complexation. FIR and THz spectra also confirm the formation of Cs-complexes. Crystal structure, FTIR, FIR, THz and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride-lactose, cesium chloride-D- and L-arabinose complexes.

catena-Poly[[[tetraaquacobalt(II]-μ-4,4′-bipyridine-κ2N:N′] 2-[4-(2-carboxylatoethylphenoxy]acetate

Directory of Open Access Journals (Sweden)

Xi-Fang Wang

2009-07-01

Full Text Available In the title complex, {[Co(C10H8N2(H2O4](C11H10O5}n, the unique CoII ion lies on an inversion center and is coordinated by two N atoms from two 4,4′-bipyridine ligands and four O atoms from four water molecules in a slightly distorted octahedral coordination geometry. The 4,4′-bipyridine ligands bridge CoII ions into a one-dimensional chain structure. In the crystal structure, intermolecular O—H...O hydrogen bonds link cations and anions into a three-dimensional network. The dianions are completely disordered about an inversion center.

Synthesis, characterization, and reactivity of a uranium(VI) carbene imido oxo complex

Energy Technology Data Exchange (ETDEWEB)

Lu, Erli; Cooper, Oliver J.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [School of Chemistry, University of Nottingham (United Kingdom); Tuna, Floriana; McInnes, Eric J.L. [School of Chemistry and Photon Science Institute, University of Manchester (United Kingdom)

2014-06-23

We report the uranium(VI) carbene imido oxo complex [U(BIPM{sup TMS})(NMes)(O)(DMAP){sub 2}] (5, BIPM{sup TMS}=C(PPh{sub 2}NSiMe{sub 3}){sub 2}; Mes=2,4,6-Me{sub 3}C{sub 6}H{sub 2}; DMAP=4-(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two-electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T-shaped motif with respect to the carbene, which is consistent with an inverse trans-influence. Complex 5 reacts with tert-butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPM{sup TMS})(O){sub 2}(DMAP){sub 2}] (6). (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis, structure and magnetic properties of cobalt(II) and copper(II) coordination polymers assembled by phthalate and 4-methylimidazole

International Nuclear Information System (INIS)

Baca, S.G.; Malinovskii, S.T.; Franz, Patrick; Ambrus, Christina; Stoeckli-Evans, Helen; Gerbeleu, Nicolae; Decurtins, Silvio

2004-01-01

New coordination polymers [M(Pht)(4-MeIm) 2 (H 2 O)] n (M=Co (1), Cu (2); Pht 2- =dianion of o-phthalic acid; 4-MeIm=4-methylimidazole) have been synthesized and characterized by IR spectroscopy, X-ray crystallography, thermogravimetric analysis and magnetic measurements. The crystal structures of 1 and 2 are isostructural and consist of [M(4-MeIm) 2 (H 2 O)] building units linked in infinite 1D helical chains by 1,6-bridging phthalate ions which also act as chelating ligands through two O atoms from one carboxylate group in the case of 1. In complex 1, each Co(II) atom adopts a distorted octahedral N 2 O 4 geometry being coordinated by two N atoms from two 4-MeIm, three O atoms of two phthalate residues and one O atom of a water molecule, whereas the square-pyramidal N 2 O 3 coordination of the Cu(II) atom in 2 includes two N atoms of N-containing ligands, two O atoms of two carboxylate groups from different Pht, and a water molecule. An additional strong O-H↑··O hydrogen bond between a carboxylate group of the phthalate ligand and a coordinated water molecule join the 1D helical chains to form a 2D network in both compounds. The thermal dependences of the magnetic susceptibilities of the polymeric helical Co(II) chain compound 1 were simulated within the temperature range 20-300 K as a single ion case, whereas for the Cu(II) compound 2, the simulations between 25 and 300 K, were made for a linear chain using the Bonner-Fisher approximation. Modelling the experimental data of compound 1 with MAGPACK resulted in: g=2.6, vertical bar D vertical bar=62 cm -1 . Calculations using the Bonner-Fisher approximation gave the following result for compound 2: g=2.18, J=-0.4 cm -1

Iron oxide impregnated Morus alba L. fruit peel for biosorption of Co(II): biosorption properties and mechanism.

Science.gov (United States)

Koduru, Janardhan Reddy; Chang, Yoon-Young; Yang, Jae-Kyu; Kim, Im-Soon

2013-01-01

Biosorption is an ecofriendly wastewater treatment technique with high efficiency and low operating cost involving simple process for the removal of heavy metal ions from aqueous solution. In the present investigation, Morus alba L. fruit peel powder (MAFP) and iron oxide impregnated Morus alba L. fruit peel powder (IO-MAFP) were prepared and used for treating Co(II) contaminated aqueous solutions. Further the materials were characterized by using FTIR and SEM-EDX analysis. From FT-IR analysis it was found that hydroxyl, methoxy, and carbonyl groups are responsible for Co(II) biosorption. The kinetic data obtained for both biosorbents was well fitted with pseudo-second-order kinetic model. The equilibrium data was in tune with the Langmuir and Freundlich isotherm models. The thermodynamic studies were also carried and it was observed that sorption process was endothermic at 298-328 K. These studies demonstrated that both biosorbents were promising, efficient, economic, and biodegradable sorbents.

Co(II) and Cd(II) Complexes Derived from Heterocyclic Schiff-Bases: Synthesis, Structural Characterisation, and Biological Activity

Science.gov (United States)

Ahmed, Riyadh M.; Yousif, Enaam I.; Al-Jeboori, Mohamad J.

2013-01-01

New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L1) and N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L2) are reported. Schiff-base ligands L1 and L2 were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)2]Cl2 (where M = Co(II) or Cd(II), L = L1 or L2) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, 1H, and 13C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G−) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands. PMID:24027449

Engaging the Terminal: Promoting Halogen Bonding Interactions with Uranyl Oxo Atoms.

Science.gov (United States)

Carter, Korey P; Kalaj, Mark; Surbella, Robert G; Ducati, Lucas C; Autschbach, Jochen; Cahill, Christopher L

2017-11-02

Engaging the nominally terminal oxo atoms of the linear uranyl (UO 2 2+ ) cation in non-covalent interactions represents both a significant challenge and opportunity within the field of actinide hybrid materials. An approach has been developed for promoting oxo atom participation in a range of non-covalent interactions, through judicious choice of electron donating equatorial ligands and appropriately polarizable halogen-donor atoms. As such, a family of uranyl hybrid materials was generated based on a combination of 2,5-dihalobenzoic acid and aromatic, chelating N-donor ligands. Delineation of criteria for oxo participation in halogen bonding interactions has been achieved by preparing materials containing 2,5-dichloro- (25diClBA) and 2,5-dibromobenzoic acid (25diBrBA) coupled with 2,2'-bipyridine (bipy) (1 and 2), 1,10-phenanthroline (phen) (3-5), 2,2':6',2''-terpyridine (terpy) (6-8), or 4'-chloro-2,2':6',2''-terpyridine (Cl-terpy) (9-10), which have been characterized through single crystal X-ray diffraction, Raman, Infrared (IR), and luminescence spectroscopy, as well as through density functional calculations of electrostatic potentials. Looking comprehensively, these results are compared with recently published analogues featuring 2,5-diiodobenzoic acid which indicate that although inclusion of a capping ligand in the uranyl first coordination sphere is important, it is the polarizability of the selected halogen atom that ultimately drives halogen bonding interactions with the uranyl oxo atoms. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-molecule magnetism in a single-ion triamidoamine uranium(V) terminal mono-oxo complex

Energy Technology Data Exchange (ETDEWEB)

King, David M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [Nottingham Univ. (United Kingdom). School of Chemistry; Tuna, Floriana; McInnes, Eric J.L. [Manchester Univ. (United Kingdom). School of Chemistry

2013-04-26

Straightforward oxidation of a triamidoamine uranium(III) complex with trimethyl-N-oxide affords a uranium(V) terminal mono-oxo complex which is the first clear-cut example of a uranium(V) single-molecule magnet (SMM). This monometallic complex unambiguously shows that a strongly axially ligated and thus anisotropic ligand field can be used to overcome the limited magnetic anisotropy of uranium(V). [German] Die direkte Oxidation eines Triamidoamin-Uran(III)-Komplexes mit Trimethyl-N-oxid liefert einen terminalen Uran(V)-Mono(oxo)komplex, der das erste gesicherte Beispiel eines Uran(V)-Einzelmolekuelmagnets ist. Dieser monometallische Komplex zeigt eindeutig, dass ein starkes axiales und somit anisotropes Ligandenfeld die begrenzte magnetische Anisotropie von Uran(V) beseitigen kann.

Porous coordination polymer with flexibility imparted by coordinatively changeable lithium ions on the pore surface.

Science.gov (United States)

Xie, Lin-Hua; Lin, Jian-Bin; Liu, Xiao-Min; Wang, Yu; Zhang, Wei-Xiong; Zhang, Jie-Peng; Chen, Xiao-Ming

2010-02-01

Solvothermal reactions of equimolar zinc acetate, lithium acetate, and 1,3,5-benzenetricarboxylic acid (H(3)btc) in different mixed solvents yielded isostructural three-dimensional frameworks [LiZn(btc)(cG)].lG [cG and lG denote coordinated and lattice guests, respectively; cG = (nmp)(0.5)(H(2)O)(0.5), lG = (EtOH)(0.5) (1a); cG = H(2)O, lG = EtOH (1b); nmp = N-methyl-2-pyrrolidone] with one-dimensional channels occupied by guest molecules and solvent-coordinated, extrusive Li(+) ions. Thermogravimetry analyses and powder X-ray diffraction measurements revealed that both 1a and 1b can lose all lattice and coordinated guests to form a desolvated phase [LiZn(btc)] (MCF-27, 1) and almost retains the original framework structure. Gas adsorption measurements on 1 confirmed its permanent porosity but suggested a structural transformation from 1a/1b to 1. It is noteworthy that only 1a can undergo a single-crystal to single-crystal (SCSC) transformation into 1 upon desolvation. The crystal structure of 1 revealed that the Li(+) ions were retracted into the channel walls via complementary coordination to the carboxylate oxygen atoms in the framework rather than being exposed on the pore surface. Single-crystal X-ray diffraction analyses were also performed for N(2)- and CO(2)-loaded samples of 1, revealing that the framework remained unchanged when the gases were adsorbed. Although the gas molecules could not be modeled, the residue electrons inside the channels demonstrated that the retracted Li(+) ions still behave as the primary interacting site for CO(2) molecules. Nevertheless, solvent molecules such as H(2)O can readily compete with the framework oxygen atom to retrieve the extrusive Li(+) ions, accompanying the reverse structural transformation, i.e., from 1 to 1a/1b.

Synthesis, Characterization and Antimicrobial Activity of Cu(II, Co(II and Ni(II Complexes with O, N, and S Donor Ligands

Directory of Open Access Journals (Sweden)

Vidyavati Reddy

2008-01-01

Full Text Available The complexes of the type ML2 [where M = Cu(II, Co(II, and Ni(II] L = 1-phenyl-1-ene-3-(2-hydroxyphenyl-prop-2-ene with 3- substituted-5-mercapto-4-amino-1,2,4-triazoles. Schiff base ligands have been prepared by reacting 3-(2-hydroxyphenyl-1-phenylprop-2-en-1-one and 3-phenyl/pyridyl-4-amino-5-mercapto-1,2,4-triazoles in an alcoholic medium. The complexes are non-electrolytes in DMF. The resulting complexes were characterized by elemental analysis, magnetic measurements, conductivity measurements and spectral studies. The Schiff base acts as a tridentate dibasic and coordinating through the deprotonated oxygen, thioenolic sulphur and azomethine nitrogen atoms. It is found that Cu(II, Co(II, and Ni(II complexes exhibited octahedral geometry. The antimicrobial activities of ligands and its complexes were screened by cup plate method.

Catalysts of Cu(II) and Co(II) ions adsorbed in chitosan used in transesterification of soy bean and babassu oils - a new route for biodiesel syntheses.

Science.gov (United States)

da Silva, Rondinelly Brandão; Lima Neto, Alcides Fernandes; Soares Dos Santos, Lucas Samuel; de Oliveira Lima, José Renato; Chaves, Mariana Helena; Dos Santos, José Ribeiro; de Lima, Geraldo Magela; de Moura, Edmilson Miranda; de Moura, Carla Verônica Rodarte

2008-10-01

Catalysts of Cu(II) and Co(II) adsorbed in chitosan was used in transesterification of soy bean and babassu oils. The catalysts were characterized by infrared, atomic absorption and TG, and biodiesels was characterized by infrared, NMR, CG, TG, physic chemistry analysis. The maximum adsorption values found for copper and cobalt cations were 1.584 and 1.260mgg(-1), respectively, in 180min. However, conversion of oils in biodiesel was better when used Co(II) adsorbed in chitosan.

Synthesis, structural studies and antimicrobial activity of N'-((2Z, 3E)-3-(hydroxyimino)butan-2-ylidene)-2-phenylacetohydrazide and its Co(II), Ni(II) complexes

Science.gov (United States)

Karadeniz, Şeyma; Ataol, Cigdem Yuksektepe; Şahin, Onur; İdil, Önder; Bati, Hümeyra

2018-06-01

A new aroylhydrazoneoxime, N'-((2Z, 3E)-3-(hydroxyimino)butan-2-ylidene)-2-phenylacetohydrazide ligand (LH2) and its Ni(II) and Co(II) complexes, have been synthesized and characterized by elemental and thermal analyses, IR and UV-vis spectroscopy, magnetic moment and X-ray diffraction. The antimicrobial activities of these compounds were tested by using minimal inhibitory concentration method (MIC). The ligand-containing aroylhydrazone and oxime groups and its Ni complex crystallize in the triclinic system and P 1 - space group, while its Co complex crystallizes in the monoclinic system and the C 2/c space group. X-ray results show that the ligand in the keto form is transformed into enolic form when it forms coordination. From elemental analysis data, the stoichiometry of Co(II) complex was found to be 1:2 (metal/ligand), but 1:1 for Ni(II). IR spectra indicate that the ligand acts as monoanionic NNO- tridentate and coordination takes place form through the oxime nitrogen, imine nitrogen, and enolate oxygen atoms.

Multinary lithium (oxo)nitridosilicates. Syntheses, structures and their materials properties

International Nuclear Information System (INIS)

Horky, Katrin

2017-01-01

The objective of this thesis was the synthesis, identification and characterization of novel lithium(oxo)nitridosilicates in order to investigate as well as to expand the materials properties of this compound class. Therefore, different synthesis strategies were carried out. Crystal structure elucidation with single-crystal X-ray diffraction was carried out on new compounds. Moreover, investigations of physical properties like luminescence and lithium ion conductivity were performed.

Multinary lithium (oxo)nitridosilicates. Syntheses, structures and their materials properties

Energy Technology Data Exchange (ETDEWEB)

Horky, Katrin

2017-11-06

The objective of this thesis was the synthesis, identification and characterization of novel lithium(oxo)nitridosilicates in order to investigate as well as to expand the materials properties of this compound class. Therefore, different synthesis strategies were carried out. Crystal structure elucidation with single-crystal X-ray diffraction was carried out on new compounds. Moreover, investigations of physical properties like luminescence and lithium ion conductivity were performed.

Algebraic and coordinate space potentials from heavy ion scattering

International Nuclear Information System (INIS)

Amos, K.; Berge, L.; Allen, L.J.; Fiedeldey, H.

1993-01-01

An inversion scheme is presented to derive the potentials of algebraic scattering theory from the corresponding S-functions. Representative heavy ion scattering data of 12 C, 14 N and 16 O ions on 208 Pb, accurately fitted by McIntyre strong absorption type S-functions, are employed to obtain exact algebraic potentials and to generalize the analytical shapes proposed previously by Alhassid et al. The coordinate space potentials corresponding to a number of S-functions are also obtained via semiclassical inversion. The major advantage of the algebraic potentials is that, at a theoretical level they are more directly related to the S-functions than are coordinate space potentials. 16 refs., 1 tab., 9 figs

Homo- and heterodinuclear coordination polymers based on a tritopic cyclam bis-terpyridine unit: Structure and rheological properties

Energy Technology Data Exchange (ETDEWEB)

Qu, Li; Fan, Jiangxia; Ren, Yong; Xiong, Kun [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Yan, Minhao, E-mail: yanminhao@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Tuo, Xianguo, E-mail: tuoxg@swust.edu.cn [Laboratory of National Defense for Radioactive Waste and Environmental Security, Southwest University of Science and Technology, Mianyang 621010 (China); Terech, Pierre [SPrAM, UMR CEA/CNRS/UJF-Grenoble 1, INAC, Grenoble F-38054 (France); Royal, Guy [Université Joseph Fourier Grenoble I, Département de Chimie Moléculaire, UMR CNRS-5250, Institut de Chimie Moléculaire de Grenoble, FR CNRS-2607, BP 53, 38041 Grenoble Cedex 9 (France)

2015-03-01

An innovative coordination polymer based on a tritopic ligand having the bis-terpyridine cyclam (CHTT) unit is explored. Homo- or heteronuclear 1D coordination polymers can be formed with bivalent metal ions such as Co(II) and Ni(II) in solvent DMF. Creep-recovery curves of the (Co{sup II}){sub 2}CHTT gels formed from 1D coordination polymers were analyzed with the Burgers model and demonstrated an original self-healing property, unusual in the class of molecular gels. The influence of the metal type was studied through the structural features using small-angle neutron scattering (SANS) experiments. In gels, the corresponding network involves genuine fibers (R ≈ 35 Å), bundles of these fibers and also a fraction of finite size aggregates (rods with aspect ratio f ≈ 3–5). We found that the distribution of these latter structural components is sensitive to the metal ions type. Such tritopic 1D coordination polymers exhibit a range of original structural features and a facile control of the developed structures in solutions and gels by tuning their thermodynamic parameters. The versatility associated to the intrinsic dynamic ability of the systems should pave the way to original properties for molecular devices. - Graphical abstract: A tritopic ligand with a bis-terpyridine cyclam (CHTT) unit can form homo- and heterobinuclear coordination polymers with bivalent metal ions in DMF. Gels exhibit a remarkable self-healing property while structures of solutions and gels are studied by small-angle neutron scattering. - Highlights: • Homo- and heteronuclear coordination polymers based on innovative tritopic ligand. • The gels formed from the coordination polymers demonstrated self-healing property. • Influence of the metal type was studied through the structural properties by SANS. • Versatility of the singular system present original properties for molecular device.

Evaluation of Stability of Complexes of Inner Transition Metal Ions with 2-Oxo-1-pyrrolidine Acetamide and Role of Systematic Errors

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Sangita Sharma

2011-01-01

Full Text Available BEST FIT models were used to study the complexation of inner transition metal ions like Y(III, La(III, Ce(III, Pr(III, Nd(III, Sm(III, Gd(III, Dy(III and Th(IV with 2-oxo-1-pyrrolidine acetamide at 30 °C in 10%, 20, 30, 40, 50% and 60% v/v dioxane-water mixture at 0.2 M ionic strength. Irving Rossotti titration method was used to get titration data. Calculations were carried out with PKAS and BEST Fortran IV computer programs. The expected species like L, LH+, ML, ML2 and ML(OH3, were obtained with SPEPLOT. Stability of complexes has increased with increasing the dioxane content. The observed change in stability can be explained on the basis of electrostatic effects, non electrostatic effects, solvating power of solvent mixture, interaction between ions and interaction of ions with solvents. Effect of systematic errors like effect of dissolved carbon dioxide, concentration of alkali, concentration of acid, concentration of ligand and concentration of metal have also been explained here.

Coordination of cassava starch to metal ions and thermolysis of ...

African Journals Online (AJOL)

Cassava starch formed Werner-type complexes with ions of metals from the transition groups. This was proven by conductivity and electron paramagnetic resonance measurements. The coordination of starch to central metal ions influenced the thermal decomposition of starch. As a rule complexes started to decompose at ...

Synthesis and characterization of ultrasound assisted “graphene oxide–magnetite” hybrid, and investigation of its adsorption properties for Sr(II) and Co(II) ions

Energy Technology Data Exchange (ETDEWEB)

Tayyebi, Ahmad; Outokesh, Mohammad, E-mail: Outokesh@sharif.edu; Moradi, Shahab; Doram, Amir

2015-10-30

Graphical abstract: - Highlights: • Narrow size magnetite NPs were synthesized by ultrasound assisted coprecipitaion method. • A formation mechanism for deposition of magnetite NPs on graphene oxide is proposed. • The formation mechanism supported using X-ray photoelectron spectroscopy analysis. • The modified Langevin equation was used for size estimation of magnetite NPs on M–GO. • Adsorption properties of M–GO for Co(II) and Sr(II) were investigated. - Abstract: Magnetite nanoparticles with a size distribution of 15–21 nm were synthesized and decorated onto surface of graphene oxide by ultrasound assisted precipitation. Size and size distribution of the obtained M–GO hybrid were appreciably finer than the hybrids prepared by stirring method. M–GO is a superparamagnetic material with saturation magnetization of 31 emu g{sup −1}. The Langevin equation was successfully applied for estimation of size of Fe{sub 3}O{sub 4} nanoparticles in M–GO hybrid, with maximum error of 17.5%. The study put forward a formation mechanism for M–GO, based on instrumental analyses. Adsorption isotherms of Sr{sup 2+} and Co{sup 2+} ions, which were fitted by Langmuir monolayer model, displayed two-fold higher capacity for Co{sup 2+} ions, presumably due to its similarity to Fe{sup 2+} (of Fe{sub 3}O{sub 4} component). Uptake of both Co{sup 2+} and Sr{sup 2+} ions were endothermic, and spontaneous, however the former proceeded through inner-shell complex formation, while the latter took place via ion exchange mechanism. Rate of adsorption of Co{sup 2+} was faster, but for both ions, chemical reaction was the rate determining step. Sorption of Sr{sup 2+} and Co{sup 2+} ions greatly increased at pHs above 5, where (1) surface zeta potential changed its sign, and (2) deprotonating reactions at the surface became complete.

Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

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Qingqing Wang

2014-09-01

Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

The Effect of the Equatorial Environment on Oxo-Group Silylation of the Uranyl Dication: A Computational Study

International Nuclear Information System (INIS)

Yahia, A.; Maron, L.; Yahia, A.; Arnold, P.L.; Love, J.B.

2010-01-01

A theoretical investigation of the reductive oxo-group silylation reaction of the uranyl dication held in a Pacman macrocyclic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single oxo group identified as a key component in promoting the reaction between the Si-X and uranium-oxo bonds. This reductive silylation reaction is also proposed to occur in an aqueous environment but was found not to operate on bare ions; in this latter case, substitution of a ligand in the equatorial plane was the most likely reaction. These results demonstrate the importance of the presence but not the identity of the equatorial ligands upon the silylation of the uranyl U-O bond. (authors)

Glutamate Ligation in the Ni(II)- and Co(II)-Responsive Escherichia coli Transcriptional Regulator, RcnR

Energy Technology Data Exchange (ETDEWEB)

Carr, Carolyn E. [Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States; Musiani, Francesco [Laboratory; Huang, Hsin-Ting [Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States; Chivers, Peter T. [Departments of Biosciences and Chemistry, Durham University, Durham DH1 3LE, United Kingdom; Ciurli, Stefano [Laboratory; Maroney, Michael J. [Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States

2017-05-18

Escherichia coli RcnR (resistance to cobalt and nickel regulator, EcRcnR) is a metal-responsive repressor of the genes encoding the Ni(II) and Co(II) exporter proteins RcnAB by binding to PRcnAB. The DNA binding affinity is weakened when the cognate ions Ni(II) and Co(II) bind to EcRcnR in a six-coordinate site that features a (N/O)5S ligand donor-atom set in distinct sites: while both metal ions are bound by the N terminus, Cys35, and His64, Co(II) is additionally bound by His3. On the other hand, the noncognate Zn(II) and Cu(I) ions feature a lower coordination number, have a solvent-accessible binding site, and coordinate protein ligands that do not include the N-terminal amine. A molecular model of apo-EcRcnR suggested potential roles for Glu34 and Glu63 in binding Ni(II) and Co(II) to EcRcnR. The roles of Glu34 and Glu63 in metal binding, metal selectivity, and function were therefore investigated using a structure/function approach. X-ray absorption spectroscopy was used to assess the structural changes in the Ni(II), Co(II), and Zn(II) binding sites of Glu → Ala and Glu → Cys variants at both positions. The effect of these structural alterations on the regulation of PrcnA by EcRcnR in response to metal binding was explored using LacZ reporter assays. These combined studies indicate that while Glu63 is a ligand for both metal ions, Glu34 is a ligand for Co(II) but possibly not for Ni(II). The Glu34 variants affect the structure of the cognate metal sites, but they have no effect on the transcriptional response. In contrast, the Glu63 variants affect both the structure and transcriptional response, although they do not completely abolish the function of EcRcnR. The structure of the Zn(II) site is not significantly perturbed by any of the glutamic acid variations. The spectroscopic and functional data obtained on the mutants were used to calculate models of the metal-site structures of EcRcnR bound to Ni(II), Co(II), and Zn(II). The results are interpreted

Two Ti13-oxo-clusters showing non-compact structures, film electrode preparation and photocurrent properties.

Science.gov (United States)

Hou, Jin-Le; Luo, Wen; Wu, Yin-Yin; Su, Hu-Chao; Zhang, Guang-Lin; Zhu, Qin-Yu; Dai, Jie

2015-12-14

Two benzene dicarboxylate (BDC) and salicylate (SAL) substituted titanium-oxo-clusters, Ti13O10(o-BDC)4(SAL)4(O(i)Pr)16 (1) and Ti13O10(o-BDC)4(SAL-Cl)4(O(i)Pr)16 (2), are prepared by one step in situ solvothermal synthesis. Single crystal analysis shows that the two Ti13 clusters take a paddle arrangement with an S4 symmetry. The non-compact (non-sphere) structure is stabilized by the coordination of BDC and SAL. Film photoelectrodes are prepared by the wet coating process using the solution of the clusters and the photocurrent response properties of the electrodes are studied. It is found that the photocurrent density and photoresponsiveness of the electrodes are related to the number of coating layers and the annealing temperature. Using ligand coordinated titanium-oxo-clusters as the molecular precursors of TiO2 anatase films is found to be effective due to their high solubility, appropriate stability in solution and hence the easy controllability.

Oxidations of Organic and Inorganic Substrates by Superoxo-, hydroperoxo-, and oxo-compounds of the transition metals

International Nuclear Information System (INIS)

Michael John Vasbinder

2006-01-01

Chapters 1 and 2 dealt with the chemistry of superoxo-, hydroperoxo-, and oxo- complexes of chromium, rhodium and cobalt. Chapter 3 dealt with the mechanism of oxygen-atom transfer catalyzed by an oxo-complex of rhenium. In Chapter 1, it was shown that hydroperoxometal complexes of cobalt and rhodium react with superoxochromium and chromyl ions, generating reduced chromium species while oxidizing the hydroperoxometal ions to their corresponding superoxometal ions. It was shown that the chromyl and superoxochromium ions are the more powerful oxidants. Evidence supports hydrogen atom transfer from the hydroperoxometal ion to the oxidizing superoxochromium or chromyl ion as the reaction mechanism. There is a significant H/D kinetic isotope effect. Comparisons to the rate constants of other known hydrogen atom transfer reactions show the expected correlation with bond dissociation energies. In Chapter 2, it was found that the superoxometal complexes Cr aq OO 2+ and Rh(NH 3 ) 4 (H 2 O)OO 2+ oxidize stable nitroxyl radicals of the TEMPO series with rate constants that correlate with the redox potentials of both the oxidant and reductant. These reactions fit the Marcus equation for electron transfer near the theoretical value. Acid catalysis is important to the reaction, especially the thermodynamically limited cases involving Rh(NH 3 ) 4 (H 2 O)OO 2+ as the oxidant. The rate constants are notably less than those measured in the reaction between the same nitroxyl radicals and other strong free-radical oxidants, an illustration of the delocalized and stabilized nature of the superoxometal ions. Chapter 3 showed that oxo-rhenium catalysts needed a nucleophile to complete the catalytic oxygen-atom transfer from substituted pyridine-N-oxides to triphenylphosphine. The reaction was studied by introducing various pyridine-derived nucleophiles and monitoring their effect on the rate, then fitting the observed rate constants to the Hammett correlation. It was found that the

Ligand Influences on Properties of Uranium Coordination Complexes - Structure, Reactivity, and Spectroscopy

OpenAIRE

Kosog, Boris

2012-01-01

In this thesis several different aspects of uranium chemistry are presented. It was shown that terminal uranium(V) oxo and imido complexes [((RArO)3tacn)UV(O)] and [((RArO)3tacn)UV(NSiMe3)] (R = t Bu, Ad) can be oxidized by silver(I) hexafluoro-antimonate to the uranium(VI) oxo and imido complexes [((RArO)3tacn)UVI(O)]SbF6 and [((RArO)3tacn)UVI(NSiMe3)]SbF6. While for the t Bu-derivative of the oxo complex an equatorial coordination is observed due to stabilization by the inverse trans-influe...

Coordination variation of hydrated Cu2+/Br1− ions traversing the interfacial water in mesopores

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Q. Wang

2012-06-01

Full Text Available Resolution of the atomistic and electronic details about the coordination structure variation of hydrated ions in the interfacial water is still a tough challenge, which is, however, essentially important for the understanding of ion adsorption, permeation and other similar processes in aqueous solutions. Here we report the tracing of coordination structure variation for hydrated Cu2+/Br1- ions traversing the interfacial water in Vycor mesopores (ϕ = 7.6 nm by employing both X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopies. By controlled desorption/adsorption of water, the filling fraction of the mesopores, thus the water layer thickness, can be adjusted, which in turn effects the variation of coordination structure of the ions therein. It is found that both Cu2+ and Br1- ions prefer staying exclusively in the core water, and in this circumstance no ion pairs have been detected in the solution of concentrations up to 1.0 M. Following capillary decondensation occurring at a filling fraction of ∼35% which corresponds to a water layer of about three monolayers, Br1- ions begin immediately to reconstruct their first coordination shell, characterized by ionic dehydration, shrinkage of ion-water bond length, and formation of ion pairs. In contrast, Cu2+ ions can retain a bulk-like coordination structure till being driven to bond directly to the pore surface when the filling fraction is below 20%. At the final stage of dehydration via thermal vacuum treatment at 110°C, Cu2+ ions can be completely reduced to the Cu1+ state, and recover at room temperature only when the filling fraction is above 14%. These results may be inspirable for the investigation of similar problems concerning hydrated ions in water solution under different confining conditions.

Investigating the pharmacodynamic and magnetic properties of pyrophosphate-bridged coordination complexes

Science.gov (United States)

Ikotun, Oluwatayo (Tayo) F.

The multidentate nature of pyrophosphate makes it an attractive ligand for complexation of metal cations. The participation of pyrophosphate in a variety of biological pathways and its metal catalyzed hydrolysis has driven our investigation into its coordination chemistry. We have successfully synthesized a library of binuclear pyrophosphate bridge coordination complexes. The problem of pyrophosphate hydrolysis to phosphate in the presence of divalent metal ions was overcome by incorporating capping ligands such as 1,10-phenanthroline and 2,2'-bipyridine prior to the addition of the pyrophosphate. The magnetic properties of these complexes was investigated and magneto-structural analysis was conducted. The biological abundance of pyrophosphate and the success of metal based drugs such as cisplatin, prompted our investigation of the cytotoxic properties of M(II) pyrophosphate dimeric complexes (where M(II) is CoII, CuII, and NiII) in adriamycin resistant human ovarian cancer cells. Thess compounds were found to exhibit toxicity in the nanomolar to picomolar range. We conducted in vitro stability studies and the mechanism of cytoxicity was elucidated by performing DNA mobility and binding assays, enzyme inhibition assays, and in vitro oxidative stress studies.

Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)] metals

OpenAIRE

Nahid Nishat; Ashraf Malik

2016-01-01

A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). All the polymeric compounds were characterized by (FT-IR) spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA) and antibacterial activities. Polymer complexes of Mn(II), Co(II) and Ni(II) show octahedral geometry, wh...

Oxo-exchange of gas-phase uranyl, neptunyl, and plutonyl with water and methanol.

Science.gov (United States)

Lucena, Ana F; Odoh, Samuel O; Zhao, Jing; Marçalo, Joaquim; Schreckenbach, Georg; Gibson, John K

2014-02-17

A challenge in actinide chemistry is activation of the strong bonds in the actinyl ions, AnO2(+) and AnO2(2+), where An = U, Np, or Pu. Actinyl activation in oxo-exchange with water in solution is well established, but the exchange mechanisms are unknown. Gas-phase actinyl oxo-exchange is a means to probe these processes in detail for simple systems, which are amenable to computational modeling. Gas-phase exchange reactions of UO2(+), NpO2(+), PuO2(+), and UO2(2+) with water and methanol were studied by experiment and density functional theory (DFT); reported for the first time are experimental results for UO2(2+) and for methanol exchange, as well as exchange rate constants. Key findings are faster exchange of UO2(2+) versus UO2(+) and faster exchange with methanol versus water; faster exchange of UO2(+) versus PuO2(+) was quantified. Computed potential energy profiles (PEPs) are in accord with the observed kinetics, validating the utility of DFT to model these exchange processes. The seemingly enigmatic result of faster exchange for uranyl, which has the strongest oxo-bonds, may reflect reduced covalency in uranyl as compared with plutonyl.

Local coordination of polyvalent metal ions in molten halide mixtures

International Nuclear Information System (INIS)

Akdeniz, Z.; Tosi, M.P.

1989-07-01

Ample experimental evidence is available in the literature on the geometry and the stability of local coordination for polyvalent metal ions in molten mixtures of their halides with alkali halides. Recent schemes for classifying this evidence are discussed. Dissociation of tetrahedral halocomplexes in good ionic systems can be viewed as a classical Mott problem of bound-state stability in a conducting matrix. More generally, structural coordinates can be constructed from properties of the component elements, to separate out systems with long-lived fourfold or sixfold coordination and to distinguish between these. (author). 11 refs, 1 fig

Concentration of ions Co(II), Ni(II) at the Tokem-250 carboxylic cation exchange for catalysts development

Science.gov (United States)

Zharkova, Valentina; Bobkova, Ludmila; Brichkov, Anton; Kozik, Vladimir

2017-11-01

Sorption and catalytic properties of the cation exchanger are investigated. It was found that the Tokem-250 has a wide operating range of pH. The value of the effective ionization constant of the functional groups of the cation exchanger (pKa) is 6.59. The Tokem-250 cation exchanger exhibits selectivity to Ni2+ ions to Co2+ (D˜103). This is probably due to the stability of ion-exchange complexes detected by the method of diffuse reflectance electron spectroscopy (ESDD). According to these data, for Co2+ ions, in contrast to Ni2+, tetragonal distortion of octahedral coordination is characteristic, which has a positive effect on the stability of complexes with Co2+. To obtain spherical catalysts on the basis of Tokem-250, cobalt-containing samples of cation exchanger were used. The developed spherical materials have catalytic activity in the reactions of deep and partial oxidation of n-heptane.

A double salt of iodobismuthate: cis-aquaiodidobis(1,10-phenanthrolinecobalt(II tris(1,10-phenanthrolinecobalt(II trans-hexa-μ2-iodido-hexaiodidotribismuthate(III

Directory of Open Access Journals (Sweden)

Jiongke Chen

2011-09-01

Full Text Available In the title complex, [Co(C12H8N23][CoI(C12H8N22(H2O][Bi3I12], conventionally abbreviated [Co(phen3][CoI(phen2(H2O][Bi3I12], where phen is 1,10-phenanthroline, the CoII atom in one cation is coordinated by six N atoms from three phen ligands in an octahedral coordination while the CoII atom in the other cation is coordinated octahedrally by four N atoms from two phen ligands, one water O atom and one I atom. In the anion, three BiIII ions adopt an octahedral coordination constructed by six I− ligands. The three BiI6 octahedra are fused together through trans face-sharing.

Zeolite-encapsulated Co(II), Mn(II), Cu(II) and Cr(III) salen complexes as catalysts for efficient selective oxidation of benzyl alcohol

Science.gov (United States)

Li, F. H.; Bi, H.; Huang, D. X.; Zhang, M.; Song, Y. B.

2018-01-01

Co(II), Mn(II), Cu(II) and Cr(III) salen type complexes were synthesized in situ in Y zeolite by the reaction of ion-exchanged metal ions with the flexible ligand molecules that had diffused into the cavities. Data of characterization indicates the formation of metal salen complexes in the pores without affecting the zeolite framework structure, the absence of any extraneous species and the geometry of encapsulated complexes. The catalytic activity results show that Cosalcyen Y exhibited higher catalytic activity in the water phase selective oxidation of benzyl alcohol, which could be attributed to their geometry and the steric environment of the metal actives sites.

Crystal structure of tetraaquabis(1,3-dimethyl-2,6-dioxo-7H-purin-7-ido-κN7cobalt(II

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Hicham El Hamdani

2017-09-01

Full Text Available The title complex, [Co(C7H7N4O22(H2O4], comprises mononuclear molecules consisting of a CoII ion, two deprotonated theophylline ligands (systematic name: 1,3-dimethyl-7H-purine-2,6-dione and four coordinating water molecules. The CoII atom lies on an inversion centre and has a slightly distorted octahedral coordination environment, with two N atoms of two trans-oriented theophylline ligands and the O atoms of four water molecules. An intramolecular hydrogen bond stabilizes this conformation. A three-dimensional supramolecular network structure is formed by intermolecular O—H...O and O—H...N hydrogen bonds.

Application of Hydrothermal and Non-Hydrothermal TiO2 Nanoporous Materials as New Adsorbents for Removal of Heavy Metal Ions from Aqueous System

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Mansoor Anbia

2016-06-01

Full Text Available Hydrothermal and non-hydrothermal spherical TiO2 nanoporous with crystalline framework were prepared by sol-gel method. The Crystalline structures, morphologies and surface texturing of materials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM and N2 adsorption-desorption isotherms. The Hydrothermal spherical TiO2 nanoporous was found to have a narrow and strong pore size distribution peaks with average of 37.8 Å and pore volume of 0.41 cm3/g and the (Brunauer–Emmett–TellerBET specific surface area of 365 m2/g. Hydrothermal and non-hydrothermal spherical TiO2 nanoporous have been used as adsorbent to study of the adsorption behavior of Pb(II, Co(II and Ni(II ions from aqueous system in a batch system. Effect of equilibrium time on adsorption Pb(II, Co(II and Ni(II ions on these adsorbent was studied The results show that the shaking time 0.5 to 10h has no serious effect on the percentage of ions removal, and the adsorption is fast in all cases. The maximum uptake capacities of Hydrothermal and non-hydrothermal spherical TiO2 nanoporous was calculated. Both hydrothermal and non-hydrothermal TiO2 nanoporous materials were found to have very good potential as new adsorbents in removal of these ions. In batch systems the maximum uptake capacities of Pb(II, Ni(II and Co(II on the hydrothermal and non-hydrothermal TiO2 nanoporous materials was Co(II > Pb(II > Ni(II and Co(II > Ni(II > Pb(II, respectively.

Sequestration of Cu(II), Ni(II), and Co(II) by ethyleneimine immobilized on silica

International Nuclear Information System (INIS)

Arakaki, Luiza N.H.; Alves, Ana Paula M.; Silva Filho, Edson C. da; Fonseca, Maria G.; Oliveira, Severino F.; Espinola, Jose Geraldo P.; Airoldi, Claudio

2007-01-01

Thermodynamic data on interaction of Cu(II), Ni(II), and Co(II) with silica modified with ethyleneimine are obtained by calorimetric titration. The amount of ethyleneimine anchored on silica surface was estimated to be 0.70 mmol g -1 . The enthalpies of binding Ni(II), Cu(II) and Co(II), are -3.59 ± 0.001, -4.88 ± 0.001, and -7.75 ± 0.003 kJ mol -1 , respectively

Single-molecule magnetism in a single-ion triamidoamine uranium(V) terminal mono-oxo complex

International Nuclear Information System (INIS)

King, David M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T.; Tuna, Floriana; McInnes, Eric J.L.

2013-01-01

Straightforward oxidation of a triamidoamine uranium(III) complex with trimethyl-N-oxide affords a uranium(V) terminal mono-oxo complex which is the first clear-cut example of a uranium(V) single-molecule magnet (SMM). This monometallic complex unambiguously shows that a strongly axially ligated and thus anisotropic ligand field can be used to overcome the limited magnetic anisotropy of uranium(V). [de

Radiation grafting of acrylamide and maleic acid on chitosan and effective application for removal of Co(II) from aqueous solutions

Science.gov (United States)

Saleh, Alaaeldine Sh.; Ibrahim, Ahmed G.; Elsharma, Emad M.; Metwally, Essam; Siyam, Tharwat

2018-03-01

The graft copolymerization has been proven as a superior polymerization technique because it combines the functional advantages of the grafted and base polymers. In this work, the radiation-induced grafting of acrylamide (AAm) and maleic acid (MA) onto chitosan (CTS) was developed and optimized by determining the grafting percentage and efficiency as a function of grafting conditions such as AAm, MA, and CTS concentrations, and absorbed dose. Fourier transform infrared spectroscopic analysis (FTIR) confirmed the graft copolymerization. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) further characterized the grafted copolymers and showed their high thermal stability. Using batch sorption experiments and 60Co as a radiotracer, poly(CTS-AAm) and poly(CTS-MA) were evaluated for Co(II) removal from aqueous solutions. The Co(II) removal increases with increasing time, pH, polymer, and Co(II) concentrations. Experimentally, P(CTS-AAm) and P(CTS-MA) show high sorption capacities of Co(II), i.e. 150 mg g-1 and 421 mg g-1, respectively, which makes them potential sorbents of Co(II) for water and wastewater treatment. Finally, the Co(II) sorption was examined using sorption isotherm and kinetic models. The sorption was best fitted to Langmuir model which suggests the sorption is of chemisorption type. On the other hand, the sorption kinetics was best represented by Elovich model which also indicates the chemical nature of Co(II) sorption on P(CTS-AAm) and P(CTS-MA).

Synthesis and characterization of some complexes with imidazole and pyrazole from saccharinate transition ions in oxidation state (II)

International Nuclear Information System (INIS)

Pineda Cedeno, Leslie William

2001-01-01

The synthesis and characterization of metal ions saccharinate of the first serie of transition with the imidazole and pyrazole molecules in water and absolute ethanol were studied. In general, it found that in this series of saccharinate of coordinated water molecules are replaced by imidazole and pyrazole molecules with different substitution patterns, generating neutral complex of molecular formula [M(Sac) 2 (L) n (H 2 O) n-4 ] and cationic complex of molecular formula [M(L) n (H 2 O) 2 ]x2Sac, [M(L) n (H 2 O) 3 ]x2Sac, [M(L) n ]x2Sac, where M = V(II), Cr(II), Mc(II), Fe(II), Co(II), Ni(II) y Zn(II); Sac = saccharinate ion; L = imidazole (imd) and pyrazole (pir) and n = 6,4,3 and 2. These compounds are soluble in DMF and insoluble in all other common solvents. In turn, synthesized compounds in water were characterized by X ray crystallography, where preliminary data of refinement cycles, generate formulas of isostructural type [M(imd) 4 (H 2 O) 2 ]x2Sac and [M(Sac) 2 (pir) 2 (H 2 O) 2 ] where M = Co(II), Ni(II). The imidazole complex crystallize in the triclinic crystal system and space group P-1, while the pyrazole complexes crystallize in the monoclinic crystal system and space group P2 (1)/n. Gradual diminution was observed in the bond distances of M-N (saccharinate ion), M-N (imidazole) and M-N (pyrazole). The complex was characterized by spectroscopic methods, magnetic and electrochemical. (author) [es

Hybrid conducting polymer materials incorporating poly-oxo-metalates for extraction of actinides; Materiaux polymeres conducteurs hybrides incorporant des polyoxometallates pour l'extraction d'actinides

Energy Technology Data Exchange (ETDEWEB)

Racimor, D

2003-09-15

The preparation and characterization of hybrid conducting polymers incorporating poly-oxo-metalates for extracting actinides is discussed. A study of the coordination of various lanthanide cations (Ce(III), Ce(IV), Nd(III)) by the mono-vacant poly-oxo-metalate {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} showed significant differences according to the cation.. Various {alpha}-A-[PW{sub 9}O{sub 34}(RPO){sub 2}]{sup 5-} hybrids were synthesized and their affinity for actinides or lanthanides was demonstrated through complexation. The first hybrid poly-oxo-metallic lanthanide complexes were then synthesized, as was the first hybrid functionalized with a pyrrole group. The electro-polymerization conditions of this pyrrole remain still to be optimized. Poly-pyrrole materials incorporating {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} or its neodymium or cerium complexes as doping agents proved to be the first conducting polymer incorporating poly-oxo-metalates capable of extracting plutonium from nitric acid. (author)

Ab initio study of ortho-meta-isomerism of Li4AB3+ ions of nitrite and phosphite oxo- and thiosalts (A=N, P; B=O, S)

International Nuclear Information System (INIS)

Charkin, O.D.; MakKi, M.L.; Charkin, O.P.

2000-01-01

In the framework of MP2(6-31*//HF/6-31G + ZPE(HF/6-31G*) and MP4SDTQ/6-31G*//MP2/6-31G* + ZPE(MP2/6-31G*) approximations ab initio calculations of surfaces of potential energy of Li 4 NO 3 + , Li 4 PO 3 + , Li 4 NS 3 + , LiPS 3 + ions and Li 3 NO 3 , Li 3 PO 3 , Li 3 NS 3 , Li 3 PS 3 molecules of lithium oxo-and thiosalts with 26 valent electrons. Several low-level energy local minimums are determined for each of these ions including (Li + ) 4 ·AB 3 3- ortho-structure of C 3V symmetry with pyramidal three-charge AB 3 3- anion and totality of meta-structures of L + ·AB 2 - ·BL 3 + ion type and AB 2 - ·BL 4 2+ ion pair of C 2V and C s symmetry with onium OLi 3 + , OLi 4 2+ cations or their thio-analogues. Equilibrium geometric parameters and relative energy of isomers, energy of different channels of decomposition, frequencies and IR-intensities of normal vibrations, characteristics of electron density distribution are determined [ru

Terminal Gold-Oxo Complexes

Energy Technology Data Exchange (ETDEWEB)

Cao, R.; Anderson, T.M.; Piccoli, P.M.B.; Schultz, A.J.; Koetzle, T.F.; Geletii, Y.V.; Slonkina, E.; Hedman, B.; Hodgson, K.O.; Hardcastle, K.I.; Fang, X.; Kirk, M.L.; Knottenbelt, S.; Kogerler, P.; Musaev, D.G.; Morokuma, K.; Takahashi, M.; Hill, C.L.; /Emory U. /Argonne /SLAC, SSRL /New Mexico U. /Iowa State U. /Toho U.

2007-10-19

In contradiction to current bonding paradigms, two terminal Au-oxo molecular complexes have been synthesized by reaction of AuCl{sub 3} with metal oxide-cluster ligands that model redox-active metal oxide surfaces. Use of K{sub 10}[{alpha}{sub 2}-P{sub 2}W{sub 17}O{sub 61}] x 20H{sub 2}O and K{sub 2}WO{sub 4} (forming the [A-PW{sub 9}O{sub 34}]{sup 9-} ligand in situ) produces K{sub 15}H{sub 2}[Au(O)(OH{sub 2})P{sub 2}W{sub 18}O{sub 68}] x 25H{sub 2}O (1); use of K{sub 10}[P{sub 2}W{sub 20}O{sub 70}(OH{sub 2}){sub 2}] x 22H{sub 2}O (3) produces K{sub 7}H{sub 2}[Au(O)(OH{sub 2})P{sub 2}W{sub 20}O{sub 70}(OH{sub 2}){sub 2}] x 27H{sub 2}O (2). Complex 1 crystallizes in orthorhombic Fddd, with a = 28.594(4) Angstroms, b = 31.866(4) Angstroms, c = 38.241(5) Angstroms, V = 34844(7) Angstroms{sup 3}, Z = 16 (final R = 0.0540), and complex 2 crystallizes in hexagonal P6(3)/mmc, with a = 16.1730(9) Angstroms, b = 16.1730(9) Angstroms, c = 19.7659(15) Angstroms, V = 4477.4(5) Angstroms{sup 3}, Z = 2 (final R = 0.0634). The polyanion unit in 1 is disorder-free. Very short ({approx}1.76 Angstroms) Au-oxo distances are established by both X-ray and 30 K neutron diffraction studies, and the latter confirms oxo and trans aqua (H2O) ligands on Au. Seven findings clarify that Au and not W is present in the Au-oxo position in 1 and 2. Five lines of evidence are consistent with the presence of d8 Au(III) centers that are stabilized by the flanking polytungstate ligands in both 1 and 2: redox titrations, electrochemical measurements, 17 K optical spectra, Au L2 edge X-ray absorption spectroscopy, and Au-oxo bond distances. Variable-temperature magnetic susceptibility data for crystalline 1 and 2 establish that both solids are diamagnetic, and {sup 31}P and {sup 17}O NMR spectroscopy confirm that both remain diamagnetic in solution. Both complexes have been further characterized by FT-IR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and other techniques.

A novel vanadosilicate with hexadeca-coordinated Cs+ ions as a highly effective Cs+ remover

International Nuclear Information System (INIS)

Datta, Shuvo Jit; Moon, Won Kyung; Choi, Do Young; Hwang, In Chul; Yoon, Kyung Byung

2014-01-01

The effective removal of 137 Cs + ions from contaminated groundwater and seawater and from radioactive nuclear waste solutions is crucial for public health and for the continuous operation of nuclear power plants. Various 137 Cs + removers have been developed, but more effective 137 Cs + removers are still needed. A novel microporous vanadosilicate with mixed-valence vanadium (V 4+ and V 5+ ) ions is now reported, which shows an excellent ability for Cs + capture and immobilization from groundwater, seawater, and nuclear waste solutions. This material is superior to other known materials in terms of selectivity, capacity, and kinetics, and at very low Cs + concentrations, it was found to be the most effective material for the removal of radioactive Cs + ions under the test conditions. This novel vanadosilicate also contains hexadeca-coordinated Cs + ions, which corresponds to the highest coordination number ever described.

Synthesis, spectroscopic characterization, electrochemistry and biological evaluation of some metal (II) complexes with ONO donor ligand containing benzo[b]thiophene and coumarin moieties

Science.gov (United States)

Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

2014-09-01

Schiff base ligand 3-chloro-N‧-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzo[b]thiophene-2-carbohydrazide and its Cu(II), Co(II), Ni(II) and Zn(II) complexes were synthesized, characterized by elemental analysis and various physico-chemical techniques like, IR, 1H NMR, ESI-mass, UV-Visible, thermogravimetry - differential thermal analysis, magnetic measurements and molar conductance. Spectral analysis indicates octahedral geometry for all the complexes. Cu(II) complex have 1:1 stoichiometry of the type [M(L)(Cl)(H2O)2], whereas Co(II), Ni(II) and Zn(II) complexes have 1:2 stoichiometric ratio of the type [M(L)2]. The bonding sites are the oxygen atom of amide carbonyl, nitrogen of azomethine function and phenolic oxygen of the Schiff base ligand via deprotonation. The thermogravimetry - differential thermal analysis studies gave evidence for the presence of coordinated water molecules in the composition of Cu(II) complex which was further supported by IR measurements. All the complexes were investigated for their electrochemical activity, but only the Cu(II) complex showed the redox property. In order to evaluate the effect of antimicrobial potency of metal ions upon chelation, ligand and its metal complexes along with their respective metal chlorides were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The results showed that the metal complexes were found to be more active than free ligand. Ligand and its complexes were screened for free radical scavenging activity by DPPH method and DNA cleavage activity using Calf-thymus DNA (Cat. No-105850).

Oxo-group-14-element bond formation in binuclear uranium(V) pacman complexes

International Nuclear Information System (INIS)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B.

2013-01-01

Simple and versatile routes to the functionalization of uranyl-derived U"V-oxo groups are presented. The oxo-lithiated, binuclear uranium(V)-oxo complexes [{(py)_3LiOUO}_2(L)] and [{(py)_3LiOUO}(OUOSiMe_3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide ''ate'' complex [Li(py)_2][(OUO)(N'')_3](N''=N(SiMe_3)_2) with the polypyrrolic macrocycle H_4L or the mononuclear uranyl (VI) Pacman complex [UO_2(py)(H_2L)], respectively. These oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo-stannylated complexes [{(R_3Sn)OUO}_2(L)] (R=nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-oxo-group exchange occurred in reactions with [TiCl(OiPr)_3] to form U-O-C bonds [{(py)_3LiOUO}(OUOiPr)(L)] and [(iPrOUO)_2(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo-functionalised by Group 14 elements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Single-molecule magnetism in a single-ion triamidoamine uranium(V) terminal mono-oxo complex

Energy Technology Data Exchange (ETDEWEB)

King, David M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [School of Chemistry, University of Nottingham (United Kingdom); Tuna, Floriana; McInnes, Eric J.L. [School of Chemistry and Photon Science Institute, University of Manchester (United Kingdom)

2013-04-26

Straightforward oxidation of a triamidoamine uranium(III) complex with trimethyl-N-oxide affords a uranium(V) terminal mono-oxo complex which is the first clear-cut example of a uranium(V) single-molecule magnet (SMM). This monometallic complex unambiguously shows that a strongly axially ligated and thus anisotropic ligand field can be used to overcome the limited magnetic anisotropy of uranium(V). (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Single-molecule magnetism in a single-ion triamidoamine uranium(V) terminal mono-oxo complex

International Nuclear Information System (INIS)

King, David M.; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T.; Tuna, Floriana; McInnes, Eric J.L.

2013-01-01

Straightforward oxidation of a triamidoamine uranium(III) complex with trimethyl-N-oxide affords a uranium(V) terminal mono-oxo complex which is the first clear-cut example of a uranium(V) single-molecule magnet (SMM). This monometallic complex unambiguously shows that a strongly axially ligated and thus anisotropic ligand field can be used to overcome the limited magnetic anisotropy of uranium(V). (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Coordination kinetics of different metal ions with the amidoximated polyacrylonitrile nanofibrous membranes and catalytic behaviors of their complexes

Energy Technology Data Exchange (ETDEWEB)

Li, Fu; Dong, Yong Chun; Kang, Wei Min; Cheng, Bowen; Qu, Xiang; Cui, Guixin [School of Textiles, Tianjin Polytechnic University, Tianjin (China)

2016-12-15

Two transition metal ions (Fe{sup 3+} and Cu{sup 2+}) and a rare earth metal ion (Ce{sup 3+}) were selected to coordinate with amidoximated polyacrylonitrile (PAN) nanofibrous membrane for preparing three metal modified PAN nanofibrous membrane complexes (M-AO-n-PANs, M = Fe, Cu, or Ce) as the heterogeneous Fenton catalysts for the dye degradation in water under visible irradiation. The coordination kinetics of three metal ions with modified PAN nanofibrous membranes was studied and the catalytic properties of the resulting complexes were also compared. The results indicated that increasing metal ion concentrations in solution or higher coordination temperature led to a significant increase in metal content, particularly in Fe and Cu contents of the complexes. Their coordination process could be described using Langmuir isotherm and pseudo-second-order kinetic equations. Moreover, Fe-AO-n-PAN had the best photocatalytic efficiency for the dye degradation in acidic medium, but a lower photocatalytic activity than Cu-AO-n-PAN in alkali medium.

Oxo-group-14-element bond formation in binuclear uranium(V) pacman complexes

Energy Technology Data Exchange (ETDEWEB)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom)

2013-07-29

Simple and versatile routes to the functionalization of uranyl-derived U{sup V}-oxo groups are presented. The oxo-lithiated, binuclear uranium(V)-oxo complexes [{(py)_3LiOUO}{sub 2}(L)] and [{(py)_3LiOUO}(OUOSiMe{sub 3})(L)] were prepared by the direct combination of the uranyl(VI) silylamide ''ate'' complex [Li(py){sub 2}][(OUO)(N''){sub 3}](N''=N(SiMe{sub 3}){sub 2}) with the polypyrrolic macrocycle H{sub 4}L or the mononuclear uranyl (VI) Pacman complex [UO{sub 2}(py)(H{sub 2}L)], respectively. These oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo-stannylated complexes [{(R_3Sn)OUO}{sub 2}(L)] (R=nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-oxo-group exchange occurred in reactions with [TiCl(OiPr){sub 3}] to form U-O-C bonds [{(py)_3LiOUO}(OUOiPr)(L)] and [(iPrOUO){sub 2}(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo-functionalised by Group 14 elements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A tetrapositive metal ion in the gas phase: Thorium(IV) coordinated by neutral tridentate ligands

International Nuclear Information System (INIS)

Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K.; Hu, Han-Shi; Li, Jun

2013-01-01

Sheltering thorium ions: A Th 4+ ion supported by three neutral tetramethyl-3-oxaglutaramide ligands (L=TMOGA) is produced in the gas phase by electrospray ionization. The thorium in chiral Th(L) 3 4+ is coordinated by nine oxygen atoms. Quantum chemical studies revealed a decrease in Th-O binding energies and bond orders and an increase in bond lengths, as the number of coordinating ligands increases. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A tetrapositive metal ion in the gas phase: Thorium(IV) coordinated by neutral tridentate ligands

Energy Technology Data Exchange (ETDEWEB)

Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Hu, Han-Shi [Department of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University (China); Li, Jun [Department of Chemistry and Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University (China); William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory (United States)

2013-07-01

Sheltering thorium ions: A Th{sup 4+} ion supported by three neutral tetramethyl-3-oxaglutaramide ligands (L=TMOGA) is produced in the gas phase by electrospray ionization. The thorium in chiral Th(L){sub 3}{sup 4+} is coordinated by nine oxygen atoms. Quantum chemical studies revealed a decrease in Th-O binding energies and bond orders and an increase in bond lengths, as the number of coordinating ligands increases. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Ligand assisted cleavage of uranium oxo-clusters

Energy Technology Data Exchange (ETDEWEB)

Nocton, Gregory; Pecaut, Jacques; Mazzanti, Marinella [Laboratoire de Reconnaissance Ionique et Chimie de Coordination, Service de Chimie Inorganique et Biologique, UMR-E 3 CEA-UJF, CEA/DSM/INAC, CEA-Grenoble, 38054 Grenoble, Cedex 09 (France); Filinchuk, Yaroslav [Swiss Norwegian Beam Lines (SNBL) at the European Synchrotron Radiation Facility (ESRF), rue Jules Horowitz, 38043 Grenoble (France)

2010-07-01

Dibenzoylmethanate replaces the bridging triflate ligands in uranium triflate poly-oxo-clusters and cleaves the U{sub 12}O{sub 20} core yielding the new [U{sub 6}O{sub 4}(OH){sub 4}({eta}-dbm){sub 12}] dibenzoylmethanate (dbm{sup -}) cluster which slowly dissociates into a monomeric complex. This reactivity demonstrates the importance of bridging ligands in stabilizing uranium poly-oxo-clusters. (authors)

Inter-laboratory validation of procedures for measuring 8-oxo-7,8-dihydrooxoguanine/8-oxo-7,8-dihydro-2`-deoxyguanosine in DNA

DEFF Research Database (Denmark)

Collins, A.R.; Gedik, C.M.; Wood, S.

2002-01-01

The aim of ESCODD, a European Commission funded Concerted Action, is to improve the precision and accuracy of methods for measuring 8-oxo-7,8-dihydroguanine (8-oxoGua) or the nucleoside (8-oxodG). On two occasions, participating laboratories received samples of different concentrations of 8-oxodG...

Synthesis, structure and magnetic property of a two-dimensional coordination polymer decorated with sine wave-like 1D double chain

Science.gov (United States)

Yao, Xiao-Qiang; Li, Dan-Yang; Xiao, Guo-Bin; Ma, Heng-Chang; Lei, Zi-Qiang; Liu, Jia-Cheng

2018-04-01

A new compound, {[Co(BPFI)(NDC)]H2O·0.5DMF}n (1) has been synthesized under hydrothermal condition by the self-assembly of V-shaped N-containing rigid ligand BPFI with Co(II) ions in the presence of H2NDC acid, where BPFI = 2,8-di(1H-imidazole-1-yl)dibenzo[b,d]furan, H2NDC = naphthalene-1,4-dicarboxylic acid. Compound 1 was characterized by elemental analysis, single crystal X-ray diffraction, FT-IR spectroscopy and UV-visible spectra. Structural analysis reveals that compound 1 is a unique dinuclear Co-based 2D (4,4) layer structure decorated with parallel double chains. In addition, magnetic study reveals the existence of antiferromagnetic coupling interactions between the Co(II) ions within the dinuclear unit of 1.

Syntheses, structures, and magnetic properties of cobalt(II) and nickel(II) coordination polymers based on a V-shaped ligand

Energy Technology Data Exchange (ETDEWEB)

Yao, Shuang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China); Yi, Fei-Yan [The School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Li, Guanghua [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Yu, Yang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China); Wang, Jing-yuan, E-mail: jywang@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences, 29 Zhongguancun East Road, Haidian District, Beijing 100190 (China); Liu, Dan, E-mail: liudan2007@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China); Song, Shu-Yan [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China)

2017-06-15

Two coordination polymers [Co{sub 2}(TA)(4,4′-bipy){sub 2}(H{sub 2}O){sub 2}]·H{sub 2}O (1) and [Ni{sub 2}(TA)(4,4′-bipy){sub 2}(H{sub 2}O){sub 4}]·3H{sub 2}O (2) were prepared by hydrothermal reactions of MCl{sub 2}·6H{sub 2}O (M = Co, Ni) with a V-shaped ligand TDPA (3,3′,4,4′-thiodiphthalic anhydride) and a I-shaped N-donor co-ligand (4,4′-bipy). They were characterized by elemental analyses, thermogravinetric analyses, and magnetic behavior. As is expected, TDPA hydrolyzes into the corresponding tetra-carboxylate acid H{sub 4}TA (3,3′,4,4′-thiodiphthalic acid) during the reactions. Co{sub 2} dimer and Ni mononuclear center are connected into two-dimensional (2D) layers by H{sub 4}TA and 4,4′-bipy bridge in 1 and 2, respectively. The most amazing feature is that 1 and 2 exhibit interesting spin-canting metamagnetism and weak ferromagnetic behavior, respectively, with the critical Néel temperature of T{sub N} =4 K for 1 and T{sub N} =13 K for 2, based on variable temperature magnetic susceptibility measurements. In low mono- or dinuclear metal system, such magnetic behaviors have rare been observed. Furthermore, complex 1 will be a potential metamagnet material. - Graphical abstract: Two Co(II) and Ni(II) coordination polymers were synthesized by hydrothermal reactions from a V-shape ligand (3,3′,4,4′-thiodiphthalic anhydride) and a I-shape ligand (4,4′-bipy), which were characterized by single crystal X-ray diffraction, elemental analyses, thermogravinetric analyses, and magnetic behavior, and exhibit interesting spin-canting metamagnetism and weak ferromagnetic behavior, respectively. - Highlights: • Two Co(II) and Ni(II) coordination polymers were successfully synthesized. • Co(II) coordination polymer shows an interesting spin-canting metamagnetism. • Ni(II) coordination polymer exhibits a weak ferromagnetic behavior.

Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

Directory of Open Access Journals (Sweden)

José Maria Rodrigues da Luz

Full Text Available Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057

catena-Poly[[[trans-diaquabis(pyridine-κNcobalt(II]-μ-(4-{N′-[1-(3-acetyl-4-methyl-1H-pyrazol-5-ylethylidene]hydrazino}benzoato-κ3O:N,N′-[bis(pyridine-κNcobalt(III]-μ-(4-{N′-[1-(3-acetyl-4-methyl-1H-pyrazol-5-ylethylidene]hydrazino}benzoato-κ3N,N′:O]perchlorate 3.66-hydrate

Directory of Open Access Journals (Sweden)

Igor O. Fritsky

2008-02-01

Full Text Available The title compound, {[Co2(C15H14N4O32(C5H5N4(H2O2]ClO4·3.66H2O}n, is a one-dimensional coordination polymer, with both CoII and CoIII centres in its structure. The ligand environment surrounding CoIII is formed by two N,N-chelating pyrazole-containing ligands and two pyridine molecules in axial positions. The high-spin CoII ions, situated at crystallographic centres of inversion, exhibit a distorted octahedral coordination mode. The ClO4− anion is linked to the polymer chain via hydrogen bonds. The chains are connected by hydrogen bonds to produce a three-dimensional structure.

Environmentally Sustainable Aluminum-Coordinated Poly(tetrahydroxybenzoquinone) as a Promising Cathode for Sodium Ion Batteries.

Science.gov (United States)

Kim, Hee Joong; Kim, Youngjin; Shim, Jimin; Jung, Kyung Hwa; Jung, Min Soo; Kim, Hanseul; Lee, Jong-Chan; Lee, Kyu Tae

2018-01-31

Na-ion batteries are attractive as an alternative to Li-ion batteries because of their lower cost. Organic compounds have been considered as promising electrode materials due to their environmental friendliness and molecular diversity. Herein, aluminum-coordinated poly(tetrahydroxybenzoquinone) (P(THBQ-Al)), one of the coordination polymers, is introduced for the first time as a promising cathode for Na-ion batteries. P(THBQ-Al) is synthesized through a facile coordination reaction between benzoquinonedihydroxydiolate (C 6 O 6 H 2 2- ) and Al 3+ as ligands and complex metal ions, respectively. Tetrahydroxybenzoquinone is environmentally sustainable, because it can be obtained from natural resources such as orange peels. Benzoquinonedihydroxydiolate also contributes to delivering high reversible capacity, because each benzoquinonedihydroxydiolate unit is capable of two electron reactions through the sodiation of its conjugated carbonyl groups. Electrochemically inactive Al 3+ improves the structural stability of P(THBQ-Al) during cycling because of a lack of a change in its oxidation state. Moreover, P(THBQ-Al) is thermally stable and insoluble in nonaqueous electrolytes. These result in excellent electrochemical performance including a high reversible capacity of 113 mA h g -1 and stable cycle performance with negligible capacity fading over 100 cycles. Moreover, the reaction mechanism of P(THBQ-Al) is clarified through ex situ XPS and IR analyses, in which the reversible sodiation of C═O into C-O-Na is observed.

Fabrication of a new samarium(III) ion-selective electrode based on 3-{l_brace}[2-oxo-1(2h)-acenaphthylenyliden]amino{r_brace}-2-thioxo -1,3-thiazolidin-4-one

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali [Islamic Azad University, Quchan (Iran, islamic Republic of). Quchan Branch. Dept. of Chemistry]. E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). Faculty of Chemistry. Center of Excellence in Electrochemistry

2007-07-01

This paper introduces the development of an original PVC membrane electrode, based on 3-{l_brace}[2-oxo-1(2H)-acenaphthylenyliden]amino{r_brace}-2-thioxo-1,3-thiazolidin-4-one (ATTO) which has revealed to be a suitable carrier for Sm{sup 3+} ions. The resulting data illustrated that the electrode shows a Nernstian slope of 19.3 {+-} 0.6 mV per decade for Sm{sup 3+} ions over a broad working concentration range of 1.0 X 10{sup -6} to 1.0 X 10{sup -1} mol L{sup -1}. The lower detection limit was found to be equal to (5.5{+-} 0.3) X 10{sup -7} mol L{sup -}'1 in the pH range of 3.5-7.5, and the response time was very short ({approx}10 s). The potentiometric sensor displayed good selectivities for a number of cations such as alkali, alkaline earth, transition and heavy metal ions. (author)

3d-4f {Co(II)3Ln(OR)4} Cubanes as Bio-Inspired Water Oxidation Catalysts.

Science.gov (United States)

Evangelisti, Fabio; Moré, René; Hodel, Florian; Luber, Sandra; Patzke, Greta Ricarda

2015-09-02

Although the {CaMn4O5} oxygen evolving complex (OEC) of photosystem II is a major paradigm for water oxidation catalyst (WOC) development, the comprehensive translation of its key features into active molecular WOCs remains challenging. The [Co(II)3Ln(hmp)4(OAc)5H2O] ({Co(II)3Ln(OR)4}; Ln = Ho-Yb, hmp = 2-(hydroxymethyl)pyridine) cubane WOC series is introduced as a new springboard to address crucial design parameters, ranging from nuclearity and redox-inactive promoters to operational stability and ligand exchange properties. The {Co(II)3Ln(OR)4} cubanes promote bioinspired WOC design by newly combining Ln(3+) centers as redox-inactive Ca(2+) analogues with flexible aqua-/acetate ligands into active and stable WOCs (max. TON/TOF values of 211/9 s(-1)). Furthermore, they open up the important family of 3d-4f complexes for photocatalytic applications. The stability of the {Co(II)3Ln(OR)4} WOCs under photocatalytic conditions is demonstrated with a comprehensive analytical strategy including trace metal analyses and solution-based X-ray absorption spectroscopy (XAS) investigations. The productive influence of the Ln(3+) centers is linked to favorable ligand mobility, and the experimental trends are substantiated with Born-Oppenheimer molecular dynamics studies.

Six-coordinate oxo-vanadium(V) dimer complex with methoxy bridging: synthesis, crystal structure, biological activity and molecular docking

Czech Academy of Sciences Publication Activity Database

Heidari, F.; Fatemi, S.J.A.; Yousef Ebrahimipour, S.; Ebrahimnejad, H.; Castro, J.; Dušek, Michal; Eigner, Václav

2017-01-01

Roč. 76, Feb (2017), s. 1-4 ISSN 1387-7003 R&D Projects: GA MŠk(CZ) LO1603; GA ČR(CZ) GA14-03276S EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : oxo-vanadium(V) * Schiff base complex * antimicrobial activity * X-ray crystal structure Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.640, year: 2016

Extraction of Eu(III) and Co(II) by dihexyl N,N-diethyl carbamoyl methyl phosphonate (DHDECMP) and thenoyl trifluoroacetone (HTTA)

International Nuclear Information System (INIS)

Someda, H.H.; El-Zahhar, A.A.; Shehata, M.K.; El-Naggar, H.A.

2001-01-01

The extraction of Eu(III) has been carried out from nitrate solution using DHDECMP. Different parameters affecting the distribution of metal ion have been studied. The distribution of Eu(III) was found to be first order dependent on pH and second order with respect to [DHDECMP]. DHDECMP showed high stability towards γ-radiation dose up to 26.5 megarad. The extraction of Co(II) by either DHDECMP or HTTA from acetate solution showed that it is second order dependent on both the extractant concentration and the pH. Based on the data of the distribution ratio obtained and the calculated thermodynamic parameters; reaction mechanisms are suggested. (author)

Adsorption of heavy metal ions on molybdenum and molybdenum trioxide from dilute aqueous solution

International Nuclear Information System (INIS)

Utsunomiya, Taizo; Hoshino, Yoshio; Sakabe, Ken-ichi

1984-01-01

The adsorption of heavy metal ions such as Co(II), Cu(II) and Pb(II) on molybdenum powder has been investigated by the batch technique as a function of soaking time, concentration of heavy metal ions and coexisting salts, pH etc. Molybdenum trioxide was also used as an adsorbent for a comparison to discuss the adsorption mechanism. The amount of these heavy metal ions adsorbed was highly pH and coexisting salts dependent. These adsorbents have features of selective adsorption for Pb(II) and large adsorption rate. The adsorption of heavy metal ions on these adsorbents proceeds independently or concurrently by following complex mechanism; (1) cation exchange reaction by hydroxyl radical on the surface of Mo and MoO 3 is predominant for most of heavy metal ions except Pb(II) [Co(II), Mn(II), Fe(III), Ni(II), Zn(II), Cd(II) and Sr(II)], (2) reduction (electron exchange reaction) to low ionic or metallic state after cation exchange reaction [Cu(II) and Ag(I) on Mo] and (3) formation of a compound [Pb(II) on both Mo and MoO 3 ]. (author)

Construction of Insulin 18-mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites

DEFF Research Database (Denmark)

Munch, Henrik K.; Nygaard, Jesper; Christensen, Niels Johan

2016-01-01

coordination with two different metal ions. Selective attachment of an abiotic 2,2′-bipyridine (bipy) ligand to HI, yielding HI–bipy, enabled ZnII-binding hexamers to SA into trimers of hexamers, [[HI–bipy]6]3, driven by octahedral coordination to a FeII ion. The structures were studied in solution by small...

Ni(II) ion-imprinted solid-phase extraction and preconcentration in aqueous solutions by packed-bed columns

International Nuclear Information System (INIS)

Ersoez, Arzu; Say, Ridvan; Denizli, Adil

2004-01-01

Solid-phase extraction (SPE) columns packed with materials based on molecularly imprinted polymers (MIPs) were used to develop selective separation and preconcentration for Ni(II) ion from aqueous solutions. SPE is more rapid, simple and economical method than the traditional liquid-liquid extraction. MIPs were used as column sorbent to increase the grade of selectivity in SPE columns. In this study, we have developed a polymer obtained by imprinting with Ni(II) ion as a ion-imprinted SPE sorbent. For this purpose, NI(II)-methacryloylhistidinedihydrate (MAH/Ni(II)) complex monomer was synthesized and polymerized with cross-linking ethyleneglycoldimethacrylate to obtain [poly(EGDMA-MAH/Ni(II))]. Then, Ni(II) ions were removed from the polymer getting Ni(II) ion-imprinted sorbent. The MIP-SPE preconcentration procedure showed a linear calibration curve within concentration range from 0.3 to 25 ng/ml and the detection limit was 0.3 ng/ml (3 s) for flame atomic absorption spectrometry (FAAS). Ni(II) ion-imprinted microbeads can be used several times without considerable loss of adsorption capacity. When the adsorption capacity of nickel imprinted microbeads were compared with non-imprinted microbeads, nickel imprinted microbeads have higher adsorption capacity. The K d (distribution coefficient) values for the Ni(II)-imprinted microbeads show increase in K d for Ni(II) with respect to both K d values of Zn(II), Cu(II) and Co(II) ions and non-imprinted polymer. During that time K d decreases for Zn(II), Cu(II) and Co(II) ions and the k' (relative selectivity coefficient) values which are greater than 1 for imprinted microbeads of Ni(II)/Cu(II), Ni(II)/Zn(II) and Ni(II)/Co(II) are 57.3, 53.9, and 17.3, respectively. Determination of Ni(II) ion in sea water showed that the interfering matrix had been almost removed during preconcentration. The column was good enough for Ni determination in matrixes containing similar ionic radii ions such as Cu(II), Zn(II) and Co(II)

Poly[[[diaquacobalt(II]-bis[μ2-1,1′-(butane-1,4-diyldiimidazole-κ2N3:N3′

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available In the title compound, {[Co(C10H14N42(H2O2](NO32}n, the CoII ion lies on an inversion center and is six-coordinated in an octahedral environment by four N atoms from four different 1,1′-butane-1,4-diyldiimidazole ligands and two O atoms from the two water molecules. The CoII atoms are bridged by ligands, generating a two-dimensional (4,4-network. Adjacent fishnet planes are linked to the nitrate anions via O—H...O hydrogen bonds, forming a three-dimensional supramolecular structure.

Study of coordinated system Zn(II)- isoleucine-isoleuciante ion; Estudio del sistema coordinado Zn(II)-Isoleucina neutra-ion isolencionato

Energy Technology Data Exchange (ETDEWEB)

Ruiz Morales, J.C.; Cuesta Gonzalez, M. de la; Cuesta Sanchez, M.; Rodriguez-Placeres, J.C. [Departamento de Quimica Fisica, Universidad de la Laguna, Tenerife (Spain)

1996-11-01

The polarographic method has been applied to the study of the coordinated system Zn(II)-isoleucine-isoleucinate ion, in aqueous medium, l=1.0M(NaClO{sub 4}) and T=25+- 0.05 degree centigree. The stabilization of the coordinated species [Zn(HI)]``2+ (Beta{sub 1}0=1.7), [Zn(I)]``+ (Beta{sub 0}1=5.6.10``4) and [Zn(HI)(I)]``+ (Beta{sub 1}1=1.1.10``5) has been stablished. (Author) 12 refs.

Mononuclear late first row transition metal complexes of ONO donor hydrazone ligand: Synthesis, characterization, crystallographic insight, in vivo and in vitro anti-inflammatory activity

Science.gov (United States)

Kendur, Umashri; Chimmalagi, Geeta H.; Patil, Sunil M.; Gudasi, Kalagouda B.; Frampton, Christopher S.; Mangannavar, Chandrashekhar V.; Muchchandi, Iranna S.

2018-02-01

Air and moisture stable coordination compounds of late first row transition metal ions, viz., Co(II), Ni(II), Cu(II) and Zn(II) with a newly designed ligand, (E)-2-amino-N'-(1-(2-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl)ethylidene)benzohydrazide (H2L) were prepared and extensively characterized using various spectro-analytical techniques. The ligand acts both in mono as well as doubly deprotonated manner. The ligand to metal stoichiometry was found to be 1:2 in case of complexes using chloride salts, whereas 1:1 in case of copper (II) complex using its acetate salt. The molecular structures of H2L, nickel and copper complexes were unambiguously determined by single-crystal X-ray diffraction studies reveal that H2L exists in a zwitterionic form while copper complex has copper centre in a distorted square planar environment. On the other hand, cobalt, nickel and zinc complexes display distorted octahedral coordination around the metal ion. In case of [Ni(HL)2].H2O, intramolecular Csbnd H⋯π stacking interaction were observed between the centroid of five membered chelate ring and phenyl proton C5sbnd H5 and intermolecular Csbnd H⋯π stacking interaction between the centroid of phenyl ring, dehydroacetic acid (DHA) ring and phenyl protons. The [Cu(L)DMF] complex is stabilized by intramolecular hydrogen bonding N1H⋯N2 and by intermolecular hydrogen bonding N1H⋯O4. Intermolecular interactions were investigated by Hirshfeld surfaces. Further, H2L and its metal complexes were screened for their in vivo and in vitro anti-inflammatory activities. The activity of the ligand has enhanced on coordination with transition metals. The tested compounds have shown excellent activity, which is almost equipotent to the standard used in the study.

α-Oxo-Ketenimines from Isocyanides and α-Haloketones: Synthesis and Divergent Reactivity.

Science.gov (United States)

Mamboury, Mathias; Wang, Qian; Zhu, Jieping

2017-09-18

The palladium-catalyzed reaction of α-haloketones with isocyanides afforded α-oxo-ketenimines through β-hydride elimination of the β-oxo-imidoyl palladium intermediates. Reaction of these relatively stable α-oxo-ketenimines with nucleophiles such as hydrazines, hydrazoic acid, amines, and Grignard reagent afforded pyrazoles, tetrazole, β-keto amidines, and enaminone, respectively, with high chemoselectivity. Whereas amines attack exclusively on the ketenimine functions, the formal [3+2] cycloaddition between N-monosubstituted hydrazines and α-oxo-ketenimines was initiated by nucleophilic addition to the carbonyl group. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coordinate transformation based cryo-correlative methods for electron tomography and focused ion beam milling

International Nuclear Information System (INIS)

Fukuda, Yoshiyuki; Schrod, Nikolas; Schaffer, Miroslava; Feng, Li Rebekah; Baumeister, Wolfgang; Lucic, Vladan

2014-01-01

Correlative microscopy allows imaging of the same feature over multiple length scales, combining light microscopy with high resolution information provided by electron microscopy. We demonstrate two procedures for coordinate transformation based correlative microscopy of vitrified biological samples applicable to different imaging modes. The first procedure aims at navigating cryo-electron tomography to cellular regions identified by fluorescent labels. The second procedure, allowing navigation of focused ion beam milling to fluorescently labeled molecules, is based on the introduction of an intermediate scanning electron microscopy imaging step to overcome the large difference between cryo-light microscopy and focused ion beam imaging modes. These methods make it possible to image fluorescently labeled macromolecular complexes in their natural environments by cryo-electron tomography, while minimizing exposure to the electron beam during the search for features of interest. - Highlights: • Correlative light microscopy and focused ion beam milling of vitrified samples. • Coordinate transformation based cryo-correlative method. • Improved correlative light microscopy and cryo-electron tomography

Highly selective potentiometric and colorimetric determinations of cobalt (II) ion using thiazole based ligands.

Science.gov (United States)

Singhal, Divya; Singh, Ashok Kumar; Upadhyay, Anjali

2014-12-01

New PVC-membrane electrodes were prepared by using 2-((thiazol-2-ylimino)methyl)phenol (L1) and 2-((thiazol-2-ylamino)methyl)phenol (L2) and explored as Co(II) selective electrodes. The effect of various plasticizers and anion excluder was studied in detail and improved performance was observed. It was found that the electrode based on L1 shows better response characteristics in comparison to L2. Optimum performance was observed for the membrane electrode having a composition of L1:NaTPB:DBP:PVC≡2:8:78:62 (w/w, mg). The performance of PME based on L1 was compared with that of CGE. The electrodes exhibit Nernstian slope for Co(II) ions with a limit of detection of 6.91×10(-7) mol L(-1) for PME and 7.94×10(-8) mol L(-1) for CGE. The response time for PME and CGE was found to be 15s and 12 s respectively. The potentiometric responses are independent in the pH range 3.0-9.0 for CGE. The CGE could be used for a period of 90 days. The CGE was used as an indicator electrode in potentiometric titration of EDTA with Co(2+) ion. Further the selectivity of the L1 and L2 was also confirmed by the UV-vis and colorimetric studies and found that L1 is more selective for Co(II) ion. Copyright © 2014 Elsevier B.V. All rights reserved.

Study of new rubber to steel adhesive systems based on Co(II and Cu(II sulphides coats

Directory of Open Access Journals (Sweden)

Labaj Ivan

2018-01-01

Full Text Available The presented paper deals with the preparation of new rubber to steel adhesive systems using the steel surface treatment with deposition of adhesive coats based on Co(II and Cu(II sulphides. Efficiency of new prepared adhesive systems containing Co(II and Cu(II sulphides has been compared with the efficiency of double layer adhesive system commonly used in industry. The chemical composition of prepared adhesive systems was determined using the EDX analysis. Scanning Electron Microscopy (SEM was used for study of topography and microstructure of prepared rubber to steel adhesive systems (Co(II, Cu(II sulphide, double layer adhesive system. For determination of adhesion strength between rubber blends and metal pieces with various adhesive systems deposited on these pieces, the test according to ASTM D429 standard relating to Rubber to metal adhesion, method A was used. For all test samples, the same type of rubber blend and the same curing conditions have been used.

Synthesis, structure and properties of oxo- and dioxochloride complexes of molybdenum(VI) and tungsten(VI) with 8-oxyquinoline

International Nuclear Information System (INIS)

Abramenko, V.L.; Sergienko, V.S.; Egorova, O.A.

2005-01-01

Complexes of oxo- and dioxochlorides of molybdenum(VI) and tungsten(VI) with 8-oxyquinoline of molecular and intracomplex type are synthesized and studied by the method of IR spectroscopy. The complexes have octahedral structure. It is proposed that 8-oxyquinoline in molecular complexes is coordinated by central atom through nitrogen atom of heterocycle, but in intracomplex compounds - through heterocyclic nitrogen atom and oxygen atom of deprotonated OH-group. Thermal stability of the complexes is studied [ru

Enhancement of oxygen reduction at Fe tetrapyridyl porphyrin by pyridyl-N coordination to transition metal ions

International Nuclear Information System (INIS)

Maruyama, Jun; Baier, Claudia; Wolfschmidt, Holger; Bele, Petra; Stimming, Ulrich

2012-01-01

One of the promising candidates as noble-metal-free electrode catalysts for polymer electrolyte fuel cells (PEFCs) is a carbon material with nitrogen atoms coordinating iron ions embedded on the surface (Fe-N x moiety) as the active site, although the activity is insufficient compared to conventional platinum-based electrocatalysts. In order to obtain fundamental information on the activity enhancement, a simple model of the Fe-N x active site was formed by adsorbing 5,10,15,20-Tetrakis(4-pyridyl)-21H,23H-porphine iron(III) chloride (FeTPyPCl) on the basal plane of highly oriented pyrolytic graphite (HOPG), and cathodic oxygen reduction was investigated on the surface in 0.1 M HClO 4 . The catalytic activity for oxygen reduction was enhanced by loading transition metal ions (Co 2+ , Ni 2+ , Cu 2+ ) together with FeTPyPCl. The X-ray photoelectron spectrum of the surface suggested that the metal was coordinated by the pyridine-N. The enhancement effect of the transition metals was supported by two different measurements: oxygen reduction at HOPG in 0.1 M HClO 4 dissolving FeTPyPCl and the metal ions; oxygen reduction in 0.1 M HClO 4 at the subsequently well-rinsed and dried HOPG. The ultraviolet–visible spectrum for the solution also suggested the coordination between the pyridyl-N and the metal ions. The oxygen reduction enhancement was attributed to the electronic interaction between the additional transition metal and the Fe center of the porphyrin through the coordination bonds. These results implied that the improvement of the activity of the noble-metal-free catalyst would be possible by the proper introduction of the transition metal ions around the active site.

Physicochemical properties of 3,4,5-trimethoxybenzoates of Mn(II, Co(II, Ni(II and Zn(II

Directory of Open Access Journals (Sweden)

W. FERENC

2005-09-01

Full Text Available The complexes of Mn(II, Co(II, Ni(II, Cu(II and Zn(II with 3,4,5-trimethoxybenzoic acid anion of the formula: M(C10H11O52·nH2O, where n = 6 for Ni(II, n = 1 for Mn(II, Co(II, Cu(II, and n = 0 for Zn, have been synthesized and characterized by elemental analysis, IR spectroscopy, X–ray diffraction measurements, thermogravimetry and magnetic studies. They are crystalline compounds characterized by various symmetry. They decompose in various ways when heated in air to 1273 K. At first, they dehydrate in one step and form anhydrous salts. The final products of decomposition are oxides of the respective metals (Mn2O3, Co3O4, NiO, CuO, ZnO. The solubilities of the analysed complexes in water at 293 K are in the orders of 10-2 – 10-4 mol dm-3. The magnetic susceptibilities of the Mn(II, Co(II, Ni(II and Cu(II complexes were measured over the range of 76–303 K and the magnetic moments were calculated. The results show that the 3,4,5-trimethoxybenzoates of Mn(II, Co(II and Ni(II are high-spin complexes but that of Cu(II forms a dimer [Cu2(C10H11O54(H2O2]. The carboxylate groups bind as monodentate or bidentate chelating or bridging ligands.

Tetra-, Penta- and Hexa-Coordinated Transition Metal Complexes Constructed from Coumarin-Containing N2O2 Ligand

Directory of Open Access Journals (Sweden)

Lei Gao

2018-02-01

Full Text Available Three newly designed complexes, [Cu(L]·CHCl3 (1, [Co(L(MeOH]·CHCl3 (2 and [{Ni(L(MeOH(PhCOO}2Ni] (3 a coumarin-containing Salamo-type chelating ligand (H2L have been synthesized and characterized by elemental analyses, IR and UV-VIS spectra, and X-ray crystallography. Complex 1 includes one Cu(II atom, one completely deprotonated (L2− unit and one crystalling chloroform molecule, the Cu(II atom shows a square-planar geometry. Complex 2 includes one Co(II atom, one completely deprotonated (L2− unit, one coordinated methanol molecule and one crystalling chloroform molecule. The Co(II atom is a distorted trigonal-bipyramidal geometry. While complex 3 includes three Ni(II atoms, two completely deprotonated (L2− units, two benzoates and two coordinated methanol molecules. The complexes 1 and 2 are both possess three-dimensional supra-molecular structures by abundant noncovalent interactions. But, complex 3 formed a two-dimensional supra-molecular structure by intra-molecular hydrogen bonds. In addition, the antimicrobial and fluorescence properties of H2L and its complexes 1, 2 and 3 were also investigated.

(2,4-Dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylato-κ2O4,O5(4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylato-κ2O4,O5bis(1,10-phenanthroline-κ2N,N′yttrium(III dihydrate

Directory of Open Access Journals (Sweden)

Zilu Chen

2008-09-01

Full Text Available In the title compound, [Y(C5H2N2O4(C5H3N2O4(C12H8N22]·2H2O, the YIII ion lies on a twofold rotation axis and exhibits a distorted square-antiprismatic coordination geometry. It is chelated by two 1,10-phenanthroline ligands, a 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate monoanion and a 4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylate dianion. The H atom involved in an N—H...N hydrogen bond between the 1,2-dihydropyrimidine units has half occupancy and is disordered around a twofold rotation axis.

A novel vanadosilicate with hexadeca-coordinated Cs{sup +} ions as a highly effective Cs{sup +} remover

Energy Technology Data Exchange (ETDEWEB)

Datta, Shuvo Jit; Moon, Won Kyung; Choi, Do Young; Hwang, In Chul; Yoon, Kyung Byung [Sogang Univ., Seoul (Korea, Republic of). Korea Center for Artificial Photosynthesis

2014-07-07

The effective removal of {sup 137}Cs{sup +} ions from contaminated groundwater and seawater and from radioactive nuclear waste solutions is crucial for public health and for the continuous operation of nuclear power plants. Various {sup 137}Cs{sup +} removers have been developed, but more effective {sup 137}Cs{sup +} removers are still needed. A novel microporous vanadosilicate with mixed-valence vanadium (V{sup 4+} and V{sup 5+}) ions is now reported, which shows an excellent ability for Cs{sup +} capture and immobilization from groundwater, seawater, and nuclear waste solutions. This material is superior to other known materials in terms of selectivity, capacity, and kinetics, and at very low Cs{sup +} concentrations, it was found to be the most effective material for the removal of radioactive Cs{sup +} ions under the test conditions. This novel vanadosilicate also contains hexadeca-coordinated Cs{sup +} ions, which corresponds to the highest coordination number ever described.

Synthesis of Co9S8 and CoS nanocrystallites using Co(II ...

Indian Academy of Sciences (India)

Synthesis of Co9S8 and CoS nanocrystallites using Co(II) ... hydrothermal processing,24,25 etc. However, the ..... Cobalt sulphide nanoparticles were prepared by refluxing .... CdS nanostructures in ethylenediamine.28,29 Figure 2a shows.

Synthesis, characterization and antimicrobial activity of mixed ...

African Journals Online (AJOL)

A new series of Mn(II), Fe(II), Co(II), Cu(II) and Zn(II) mixed ligands-metal complexes derived from salicylic acid (SA) and 1,10-phenanthroline (PHEN) have been synthesized and characterized by spectroscopic studies. The coordination of the two ligands towards central metal ions has been proposed in the light of ...

Synthesis, Spectral and Antimicrobial Studies of Some Co(II, Ni(II and Cu(II Complexes Containing 2-Thiophenecarboxaldehyde Moiety

Directory of Open Access Journals (Sweden)

A. P. Mishra

2012-01-01

Full Text Available Some new Schiff base metal complexes of Co(II, Ni(II and Cu(II derived from 3-chloro-4-fluoroaniline (HL1 and 4-fluoroaniline (HL2 with 2-thiophenecarboxaldehyde have been synthesized and characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR and magnetic susceptibility. The complexes exhibit coordination number 4 or 6. The complexes are colored and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand ratio. FAB-mass data show degradation pattern of the complexes. The Schiff base and metal complexes show a good activity against the bacteria; B. subtilis, E. coli and S. aureus and fungi A. niger, A. flavus and C. albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.

Preparation and properties of a monomeric Mn(IV)-oxo complex.

Science.gov (United States)

Parsell, Trenton H; Behan, Rachel K; Green, Michael T; Hendrich, Michael P; Borovik, A S

2006-07-12

Manganese-oxo complexes have long been investigated because of their proposed roles in biological and chemical catalysis. However, there are few examples of monomeric complexes with terminal oxo ligands, especially those with oxomanganese(IV) units. A oxomanganese(IV) complex has been prepared from [MnIIIH3buea(O)]2- ([H3buea]3-, tris[(N'-tert-butylureaylato)-N-ethylene]aminato), a monomeric MnIII-O complex in which the oxo ligand arises from cleavage of dioxygen. Treating [MnIIIH3buea(O)]2- with [Cp2Fe]BF4 in either DMF at -45 degrees C or DMSO at room temperature produces [MnIVH3buea(O)]-: lambdamax = 635 nm; nu(Mn-16O) = 737 cm-1; nu(Mn-18O) = 709 cm-1; g = 5.15, 2.44, 1.63, D = 3.0 cm-1, E/D = 0.26, aMn = 66 G (A = 190 MHz). These spectroscopic properties support the assignment of a mononuclear MnIV-oxo complex with an S = 3/2 ground state. Density functional theory supports this assignment and the Jahn-Teller distortion around the high-spin MnIV center that would alter the molecular structure of [MnIVH3buea(O)]- from trigonal symmetry (as indicated by the highly rhombic EPR signal). [MnIVH3buea(O)]- is relatively unstable in DMSO, converting to [MnIIIH3buea(OH)]- via a proposed X-H bond cleavage. [MnIVH3buea(O)]- reacts with 1,2-diphenylhydrazine to from azobenzene (95% yield) and [MnIIIH3buea(OH)]-. The MnIV-oxo does not react with triphenyl- or tricyclohexylphosphine. However, O-atom transfer is observed with methyldiphenylphosphine and dimethylphenylphosphine, producing the corresponding phosphine oxides. These results illustrate the diverse reactivity of the MnIV-oxo unit.

Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

OpenAIRE

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as su...

Subtle interactions and electron transfer between UIII, NpIII, or PuIII and uranyl mediated by the oxo group

International Nuclear Information System (INIS)

Arnold, Polly L.; Zegke, Markus; Hollis, Emmalina; Pecharman, Anne-Frederique; Love, Jason B.; Dutkiewicz, Michal S.; Walter, Olaf; Apostolidis, Christos; Magnani, Nicola; Griveau, Jean-Christophe; Colineau, Eric; Caciuffo, Roberto; Zhang, Xiaobin; Schreckenbach, Georg

2016-01-01

A dramatic difference in the ability of the reducing An III center in AnCp 3 (An=U, Np, Pu; Cp=C 5 H 5 ) to oxo-bind and reduce the uranyl(VI) dication in the complex [(UO 2 )(THF)(H 2 L)] (L=''Pacman'' Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp 3 U forms the U IV -uranyl(V) compound that behaves as a U V -localized single molecule magnet below 4 K. The extent of reduction by the Cp 3 Np group upon oxo-coordination is much less, with a Np III -uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np IV U V but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np III -U VI assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu III -U VI interaction is too weak to be observed in THF solvent, in agreement with calculated predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Development of a reference database for ion beam analysis. Summary report of the first research coordination meeting

International Nuclear Information System (INIS)

Vickridge, I.; Schwerer, O.

2006-01-01

A summary is given of the First Research Coordination Meeting on the Development of a Reference Database for Ion Beam Analysis, including background information, objectives, recommendations for measurements, and a list of tasks assigned to participants. The next research co-ordination meeting will be held in May 2007. (author)

Porphyrin coordination polymer nanospheres and nanorods

Science.gov (United States)

Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

2012-12-04

A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

The Formation of Metal (M=Co(II), Ni(II), and Cu(II)) Complexes by Aminosilanes Immobilized within Mesoporous Molecular Sieves

International Nuclear Information System (INIS)

Park, Dong Ho; Park, Sung Soo; Choe, Sang Joon

1999-01-01

The immobilization of APTMS(3-(2-aminoethylamino)propyltrimethoxysilane) and AAPTMS(3-(2-(2-aminoethyl) aminoethylamino)propyltrimethoxysilane) on the surface of high quality mesoporous molecular sieves MCM-41 and MCM-48 have been confirmed by F.T.-IR spectroscopy, Raman spectroscopy, 29 Si solid state NMR, and a surface polarity measurement using Reichardt's dye. The formation of metal (Co(II), Ni(II), and Cu(II)) complexes by immobilized aminosilanes have been investigated by photoacoustic spectroscopy(PAS). The assignment of UV-Vis. PAS bands makes it possible to identify the structure of metal complexes within mesoporous molecular sieves. Co(II) ion may be coordinated mainly in a tetrahedral symmetry by two APTMS onto MCM-41, and in an octahedral one by two AAPTMS. Both Ni(II) and Cu(II) coordinated by aminosilanes within MCM-41 form possibly the octahedral complexes such as [Ni(APTMS) 2 (H 2 O) 2 ] 2+ , [Ni(AAPTMS) 2 ] 2+ , [Cu(APTMS) 2 (H 2 O) 2 ] 2+ , and [Cu(AAPTMS)(H 2 O) 3 ] 2+ , respectively. The PAS band shapes of complexes onto MCM-48 are similar to those of corresponding MCM-41 with the variation of PAS intensity. Most of metal ion(II) within MCM-41 and MCM-48 are coordinated by aminosilanes without the impregnation on the surface

Molecular clusters of 3D and lower magnetic dimensionality

International Nuclear Information System (INIS)

Papaefthymiou, G.C

1991-01-01

Controlled polymerization of iron leads to the synthesis of molecular clusters of ever-increasing size, tending to extended structures. Polymerization of oxo-bridged octahedrally coordinated iron leads to clusters with 3D magnetic interactions between iron ions, while sulfide- and selenide-bridged tetrahedrally coordinated iron ions produce clusters of lower magnetic dimensionality. In this paper the magnetic properties of the resulting large molecular clusters with N ≥ 17 (where N = the number of iron ions in the cluster) are investigated for the presence of collective magnetic correlations associated with the solid state

COII "long fragment" reliability in characterisation and classification of forensically important flies

Science.gov (United States)

Aly, Sanaa M; Mahmoud, Shereen M

2016-01-01

Molecular identification of collected flies is important in forensic entomological analysis guided with accurate evaluation of the chosen genetic marker. The selected mitochondrial DNA segments can be used to properly identify species. The aim of the present study was to determine the reliability of the 635-bp-long cytochrome oxidase II gene (COII) in identification of forensically important flies. Forty-two specimens belonging to 11 species (Calliphoridae: Chrysomya albiceps, C. rufifacies, C. megacephala, Lucilia sericata, L. cuprina; Sarcophagidae: Sarcophaga carnaria, S. dux, S. albiceps, Wohlfahrtia nuba; Muscidae: Musca domestica, M. autumnalis) were analysed. The selected marker was amplified using PCR followed by sequencing. Nucleotide sequence divergences were calculated using the K2P (Kimura two-parameter) distance model, and a NJ (neighbour-joining) phylogenetic tree was constructed. All examined specimens were assigned to the correct species, formed distinct monophyletic clades and ordered in accordance with their taxonomic classification. Intraspecific variation ranged from 0 to 1% and interspecific variation occurred between 2 and 20%. The 635-bp-long COII marker is suitable for clear differentiation and identification of forensically relevant flies.

Characterization studies of 1-(4-cyano-2-oxo-1,2-dihydro-1-pyridyl)-3-(4-cyano-1,2-dihydro-1-pyridyl) propane formed from the reaction of hydroxide Ion with 1,3-Bis-(4-cyano pyridinium)propane

International Nuclear Information System (INIS)

Fiori, Simone; Schuquel, Ivania T.A.; Meyer, Emerson; Hioka, Noboru; Silva, Idelcio N. da; Politi, Mario J.; Catalani, Luiz H.; Chaimovich, Hernan

2011-01-01

The aqueous alkaline reaction of 1,3.bis(4.cyanopyridinium)propane dibromide, a reactant constituted of two pyridinium rings linked by a three.methylene bridge, generates a novel compound, 1-(4-cyano-2-oxo-1,2-dihydro-1-pyridyl)-3-(4-cyano-1,2-dihydro-1-pyridyl) propane. The reaction pathway is attributed to the proximity of the OH. ion inserted between two pyridinium moieties, which occurs only in bis(pyridinium) derivatives connected by short methylene spacers, where charge-conformational effects are important. (author)

Synthesis, structural, antibacterial and spectral studies of Co (II) complexes with salicylaldehyde and p-chloro-benzaldehyde 4-phenyl thiosemicarbazone

International Nuclear Information System (INIS)

Nur Nadia Dzulkifli; Yang Farina; Ibrahim Baba; Nazlina Ibrahim

2012-01-01

The Co(II) complexes derived from salicylaldehyde 4-phenyl thiosemicarbazone; SaOHtsc, p-chlorobenzaldehyde 4-phenyl thiosemicarbazone; ph-HClbtsc is reported and characterized based on elemental analysis, IR, magnetic susceptibility measurement, 1 H and 13 C NMR spectra. The Co(II) complexes have the molecular formula CoL 2 where the ligand corresponding to SaOHtsc and ph-HClbtsc. The elemental analysis for the ligands and complexes were in a good agreement with the theoretical values. The ligands coordinate to metal ions in different ways which is through mono negative bidentate or di negative tridentate. The magnetic susceptibility measurements showed that the CoL 2 complexes with ligand SaOHtsc are diamagnetic thus making this complexes suitable for NMR studies. The signals at the 10.04 ppm were assigned to N 2 H in the 1 H-NMR spectra of the free ligands was absent in the spectra of the complexes due to the deprotonation of the N 2 H and coordination to the metal centres. The absence of the band in IR spectrum which is assigned to v(N 2 -H) in the spectra of CoL 2 complexes is due to the deprotonation of the ligands upon complexation through azomethine nitrogen and thionic sulphur atom to metal ion. The thiosemicarbazones and its Co(II) complexes showed moderate inhibitory against bacteria Bacillus Subtilis, Staphylococcus Epidermis, Escherichia Coli and Proteus Mirabilis in 10 μg/ disc. (author)

A concise synthesis of the potent inflammatory mediator 5-oxo-ETE

DEFF Research Database (Denmark)

Tyagi, Rahul; Shimpukade, Bharat; Blättermann, Stefanie

2012-01-01

A concise and practical method for synthesis of the potent inflammatory mediator 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE, 1) from arachidonic acid in four steps and 70% overall yield is reported. Stability studies indicate that 1 can be safely handled without rigorous precautions...

Measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-guanosine in cerebrospinal fluid by ultra performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Weimann, Allan; Simonsen, Anja Hviid; Poulsen, Henrik E

2018-01-15

Increased levels of nucleosides modified by oxidation in human cerebrospinal fluid (CSF) have several times been reported in Alzheimer patients and patients suffering from Parkinson's disease. The focus has especially been on nucleosides containing the 8-hydroxylation of guanine. Only few reports on quantification of the ribonucleoside 8-oxo-7,8-dihydro-guanosine (8oxoGuo) in CSF have been published, whereas more have been published on the quantification of the deoxy-ribonucleoside 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxodGuo). The reports on the quantification of 8oxodGuo concentrations in CSF report absolute concentrations varying by a factor >10 5 in healthy humans. This could indicate that there is a serious specificity problem in some of the methods. In this paper an isotope-dilution UPLC-MS/MS method with high specificity and sensitivity for the quantification of 8oxoGuo and 8oxodGuo in CSF is presented. LLOQ for the two analytes is determined to 4pM and 2pM, respectively. The calibration curves has been tested to be linear in the range from 4 to 3,000pM for 8oxoGuo and between 2 and 3,000pM for 8oxodGuo. Using a weighting factor of 1/x the correlation coefficient "r" for both analytes is >0.999. Copyright © 2017 Elsevier B.V. All rights reserved.

Complexes of Cu(II), Ni(II), Co(II), oxovanadium(IV) and dioxouranium(VI) with N,N'-ethylenebis (2-hydroxy-4-methylpropiophenoneimine)

International Nuclear Information System (INIS)

Patel, M.M.; Patel, M.R.; Patel, M.N.; Patel, R.P.

1982-01-01

Complexes of Cu(II), Ni(II), Co(II), oxovanadium(IV) and dioxouranium(VI) with the schiff base, N,N'-ethylenebis(2-hydroxy-4-methylpropiophenoneimine)(4-MeOHPEN), have been synthesised and characterised on the basis of elemental analyses, conductivity, magnetic moment, electronic and infrared spectral data. Square-planar structures are suggested for Cu(II), Ni(II) and Co(II) complexes while a distorted square-pyramidal structure is suggested for the oxovanadium(IV) complex. (author)

Antibacterial Co(II, Ni(II, Cu(II and Zn(II complexes with biacetyl-derived Schiff bases

Directory of Open Access Journals (Sweden)

MUHAMMAD IMRAN

2010-08-01

Full Text Available The condensation reactions of biacetyl with ortho-hydroxyaniline and 2-aminobenzoic acid to form bidendate NO donor Schiff bases were studied. The prepared Schiff base ligands were further utilized for the formation of metal chelates having the general formula [ML2(H2O2] where M = Co(II, Ni(II, Cu(II and Zn(II and L = HL1 and HL2. These new compounds were characterized by conductance measurements, magnetic susceptibility measurements, elemental analysis, and IR, 1H-NMR, 13C-NMR and electronic spectroscopy. Both Schiff base ligands were found to have a mono-anionic bidentate nature and octahedral geometry was assigned to all metal complexes. All the complexes contained coordinated water which was lost at 141–160 °C. These compounds were also screened for their in vitro antibacterial activity against four bacterial species, namely: Escherichia coli, Staphylococcus aureus, Salmonella typhi and Bacillus subtilis. The metal complexes were found to have greater antibacterial activity than the uncomplexed Schiff base ligands.

Syntheses, Crystal Structures and Thermal Behaviors of Two Supramolecular Salamo-Type Cobalt(II and Zinc(II Complexes

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Gang Li

2017-07-01

Full Text Available This paper reports the syntheses of two new complexes, [Co(L1(H2O2] (1 and [{Zn(L2(μ-OAcZn(n-PrOH}2] (2, from asymmetric halogen-substituted Salamo-type ligands H2L1 and H3L2, respectively. Investigation of the crystal structure of complex 1 reveals that the complex includes one Co(II ion, one (L12− unit and two coordinated water molecules. Complex 1 shows slightly distorted octahedral coordination geometry, forming an infinite 2D supramolecular structure by intermolecular hydrogen bond and π–π stacking interactions. Complex 2 contains four Zn(IIions, two completely deprotonated (L23− moieties, two coordinated μ-OAc− ions and n-propanol molecules. The Zn(II ions in complex 2 display slightly distorted trigonal bipyramidal or square pyramidal geometries.

Effects of 12 metal ions on iron regulatory protein 1 (IRP-1) and hypoxia-inducible factor-1 alpha (HIF-1α) and HIF-regulated genes

International Nuclear Information System (INIS)

Li Qin; Chen Haobin; Huang Xi; Costa, Max

2006-01-01

Several metal ions that are carcinogenic affect cellular iron homeostasis by competing with iron transporters or iron-regulated enzymes. Some metal ions can mimic a hypoxia response in cells under normal oxygen tension, and induce expression of HIF-1α-regulated genes. This study investigated whether 12 metal ions altered iron homeostasis in human lung carcinoma A549 cells as measured by an activation of IRP-1 and ferritin level. We also studied hypoxia signaling by measuring HIF-1α protein levels, hypoxia response element (HRE)-driven luciferase reporter activity, and Cap43 protein level (an HIF-1α responsive gene). Our results show the following: (i) Ni(II), Co(II), V(V), Mn(II), and to a lesser extent As(III) and Cu(II) activated the binding of IRP-1 to IRE after 24 h, while the other metal ions had no effect; (ii) 10 of 12 metal ions induced HIF-1α protein but to strikingly different degrees. Two of these metal ions, Al(III) and Cd(II), did not induce HIF-1α protein; however, as indicated below, only Ni(II), Co (II), and to lesser extent Mn(II) and V(V) activated HIF-1α-dependent transcription. The combined effects of both [Ni(II) + As(III)] and [Ni(II) + Cr(VI)] on HIF-1α protein were synergistic; (iii) Addition of Fe(II) with Ni(II), Co(II), and Cr(VI) attenuated the induction of HIF-1α after 4 h treatment; (iv) Ni(II), Co(II), and Mn(II) significantly decrease ferritin level after 24 h exposure; (v) Ni(II), Co(II), V(V), and Mn(II) activated HRE reporter gene after 20 h treatment; (vi) Ni(II), Co(II), V(V), and Mn(II) increased the HIF-1-dependent Cap43 protein level after 24 h treatment. In conclusion, only Ni (II), Co (II), and to a lesser extent Mn(II) and V(V) significantly stabilized HIF-1α protein, activated IRP, decreased the levels of ferritin, induced the transcription of HIF-dependent reporter, and increased the expression of Cap43 protein levels (HIF-dependent gene). The mechanism for the significant stabilization and elevation of HIF-1�

Synthesis, Structures and Properties of Cobalt Thiocyanate Coordination Compounds with 4-(hydroxymethylpyridine as Co-ligand

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Stefan Suckert

2016-04-01

Full Text Available Reaction of Co(NCS2 with 4-(hydroxymethylpyridine (hmpy leads to the formation of six new coordination compounds with the composition [Co(NCS2(hmpy4] (1, [Co(NCS2(hmpy4] × H2O (1-H2O, [Co(NCS2(hmpy2(EtOH2] (2, [Co(NCS2(hmpy2(H2O2] (3, [Co(NCS2(hmpy2]n∙4 H2O (4 and [Co(NCS2(hmpy2]n (5. They were characterized by single crystal and powder X-ray diffraction experiments, thermal and elemental analysis, IR and magnetic measurements. Compound 1 and 1-H2O form discrete complexes, in which the Co(II cations are octahedrally coordinated by two terminal thiocyanato anions and four 4-(hydroxymethylpyridine ligands. Discrete complexes were also observed for compounds 2 and 3 where two of the hmpy ligands were substituted by solvent, either water (3 or ethanol (2. In contrast, in compounds 4 and 5, the Co(II cations are linked into chains by bridging 4-(hydroxymethylpyridine ligands. The phase purity was checked with X-ray powder diffraction. Thermogravimetric measurements showed that compound 3 transforms into 5 upon heating, whereas the back transformation occurs upon resolvation. Magnetic measurements did not show any magnetic exchange via the hmpy ligand for compound 5.

5f state interaction with inner coordination sphere ligands: einsteinium 3+ ion fluorescence in aqueous and organic phases

International Nuclear Information System (INIS)

Beitz, J.V.; Wester, D.W.; Williams, C.W.

1983-01-01

The interaction between 5f electron states of einsteinium 3+ ion and coordinated ligands in solution has been probed using laser-induced fluorescence. Aquo einsteinium 3+ ion was observed to fluoresce from its first excited J = 5 state in a broad-band peaking at 9260 wavenumbers. The observed fluorescence lifetimes were 1.05 microseconds and 2.78 microseconds in H 2 O and D 2 O (99+ % D atom), respectively. The non-radiative decay rates derived from the lifetime data are compared with previously reported data for Cm, Sm, Eu, Tb, and Dy aquo 3+ ions. The 5f actinide states exhibit substantially greater non-radiative decay rates than do lanthanide 4f states of similar energy gap. This provides evidence that actinide 5f electrons interact more strongly with their inner coordination sphere than do lanthanide ion 4f electrons. The fluorescence lifetime of einsteinium 3+ ion complexed with 1 formal di(2-ethylhexyl)orthophosphoric acid in h-heptane was 2.34 microseconds. 3 figures, 1 table

Synthesis, spectral, antitumor, antioxidant and antimicrobial studies on Cu(II), Ni(II) and Co(II) complexes of 4-[(1H-Benzoimidazol-2-ylimino)-methyl]-benzene-1,3-diol.

Science.gov (United States)

El-wakiel, Nadia; El-keiy, Mai; Gaber, Mohamed

2015-08-05

A new Schiff base of 2-aminobenzimidazole with 2,4-dihydroybezaldehyde (H₃L), and its Cu(II), Ni(II) and Co(II) complexes have been synthesized and characterized by elemental analyses, molar conductance, thermal analysis (TGA), inductive coupled plasma (ICP), magnetic moment measurements, IR, EI-mass, UV-Vis. and ESR spectral studies. On the basis of spectral studies and analytical data, it is evident that the Schiff base acts as dibasic tridentate ligand coordinating via deprotonated OH, NH and azomethine nitrogen atom. The results showed that Co(II) and Ni(II) complexes have tetrahedral structure while Cu(II) complexes has octahedral geometry. The kinetic and thermodynamic parameters of the thermal decomposition stages have been evaluated. The studied complexes were tested for their in vitro antimicrobial activities against some bacterial strains. The anticancer activity of the ligand and its metal complexes is evaluated against human liver Carcinoma (HEPG2) cell. These compounds exhibited a moderate and weak activity against the tested HEPG2 cell lines with IC₅₀ of 9.08, 18.2 and 19.7 μg/ml for ligand, Cu(II) and Ni(II) complexes, respectively. In vitro antioxidant activity of the newly synthesized compounds has also been evaluated. Copyright © 2015 Elsevier B.V. All rights reserved.

Ions generated from uranyl nitrate solutions by electrospray ionization (ESI) and detected with Fourier transform ion-cyclotron resonance (FT-ICR) mass spectrometry.

Science.gov (United States)

Pasilis, Sofie; Somogyi, Arpád; Herrmann, Kristin; Pemberton, Jeanne E

2006-02-01

Electrospray ionization (ESI) of uranyl nitrate solutions generates a wide variety of positively and negatively charged ions, including complex adducts of uranyl ions with methoxy, hydroxy, and nitrate ligands. In the positive ion mode, ions detected by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry are sensitive to instrumental tuning parameters such as quadrupole operating frequency and trapping time. Positive ions correspond to oligomeric uranyl nitrate species that can be characterized as having a general formula of [(UO(2))(n)(A)(m)(CH(3)OH)(s)](+) or [(UO(2))(n)(O)(A)(m)(CH(3)OH)(s)](+) with n = 1-4, m = 1-7, s = 0 or 1, and A = OH, NO(3), CH(3)O or a combination of these, although the formation of NO(3)-containing species is preferred. In the negative ion mode, complexes of the form [(UO(2))(NO(3))(m)](-) (m = 1-3) are detected, although the formation of the oxo-containing ions [(UO(2))(O)(n)(NO(3))(m)](-) (n = 1-2, m = 1-2) and the hydroxy-containing ions [(UO(2))(OH)(n)(NO(3))(m)](-) (n = 1-2, m = 0-1) are also observed. The extent of coordinative unsaturation of both positive and negative ions can be determined by ligand association/exchange and H/D exchange experiments using D(2)O and CD(3)OD as neutral reaction partners in the gas-phase. Positive ions are of varying stability and reactivity and may fragment extensively upon collision with D(2)O, CD(3)OD and N(2) in sustained off-resonance irradiation/collision-induced dissociation (SORI-CID) experiments. Electron-transfer reactions, presumably occurring during electrospray ionization but also in SORI-CID, can result in reduction of U(VI) to U(V) and perhaps even U(IV).

A non-diazo approach to α-oxo gold carbenes via gold-catalyzed alkyne oxidation.

Science.gov (United States)

Zhang, Liming

2014-03-18

intermolecular approach offers excellent synthetic flexibility because no tethering of the oxidant is required, and its reduced form is not tangled with the product. We were the first research group to develop this strategy, through the use of pyridine/quinolone N-oxides as the external oxidants. In this manner, we can effectively make a C-C triple bond a surrogate of an α-diazo carbonyl moiety in various gold catalyses. With terminal alkynes, we demonstrated that we can efficiently trap exclusively formed terminal carbene centers by internal nucleophiles en route to the formation of cyclic products, including strained oxetan-3-ones and azetidin-3-ones, and by external nucleophiles when a P,N-bidentate ligand is coordinated to gold. With internal alkynes, we generated synthetically useful regioselectivities in the generation of the α-oxo gold carbene moiety, which enables expedient formation of versatile enone products. Other research groups have also applied this strategy en route to versatile synthetic methods. The α-oxo gold carbenes appear to be more electrophilic than their Rh counterpart, which many chemists have focused on in a large array of excellent work on metal carbene chemistry. The ease of accessing the reactive gold carbenes opens up a vast area for developing new synthetic methods that would be distinctively different from the known Rh chemistry and promises to generate a new round of "gold rush".

A Non-Diazo Approach to α-Oxo Gold Carbenes via Gold-Catalyzed Alkyne Oxidation

Science.gov (United States)

2015-01-01

intermolecular approach offers excellent synthetic flexibility because no tethering of the oxidant is required, and its reduced form is not tangled with the product. We were the first research group to develop this strategy, through the use of pyridine/quinolone N-oxides as the external oxidants. In this manner, we can effectively make a C–C triple bond a surrogate of an α-diazo carbonyl moiety in various gold catalyses. With terminal alkynes, we demonstrated that we can efficiently trap exclusively formed terminal carbene centers by internal nucleophiles en route to the formation of cyclic products, including strained oxetan-3-ones and azetidin-3-ones, and by external nucleophiles when a P,N-bidentate ligand is coordinated to gold. With internal alkynes, we generated synthetically useful regioselectivities in the generation of the α-oxo gold carbene moiety, which enables expedient formation of versatile enone products. Other research groups have also applied this strategy en route to versatile synthetic methods. The α-oxo gold carbenes appear to be more electrophilic than their Rh counterpart, which many chemists have focused on in a large array of excellent work on metal carbene chemistry. The ease of accessing the reactive gold carbenes opens up a vast area for developing new synthetic methods that would be distinctively different from the known Rh chemistry and promises to generate a new round of “gold rush”. PMID:24428596

Simultaneous ionization and analysis of 84 anabolic androgenic steroids in human urine using liquid chromatography-silver ion coordination ionspray/triple-quadrupole mass spectrometry.

Science.gov (United States)

Kim, So-Hee; Cha, Eun-Ju; Lee, Kang Mi; Kim, Ho Jun; Kwon, Oh-Seung; Lee, Jaeick

2014-01-01

Metal ion coordination ionspray (M(+) CIS) ionization is a powerful technique to enhance ionization efficiency and sensitivity. In this study, we developed and validated an analytical method for simultaneous ionization and analysis of 84 anabolic androgenic steroids (65 exogenous and 19 endogenous) using liquid chromatography-silver ion coordination ionspray/triple-quadrupole mass spectrometry (LC-Ag(+) CIS/MS/MS). The concentrations of silver ions and organic solvents have been optimized to increase the amount of silver ion coordinated complexes. A combination of 25 μM of silver ions and methanol showed the best sensitivity. The validation results showed the intra- (0.8-9.2%) and inter-day (2.5-14.9%) precisions, limits of detection (0.0005-5.0 ng/mL), and matrix effect (71.8-100.3%) for the screening analysis. No significant ion suppression was observed. In addition, this method was successfully applied to analysis of positive samples from suspected abusers and useful for the detection of the trace levels of anabolic steroids in human urine samples. Copyright © 2014 John Wiley & Sons, Ltd.

Modelling the magnetic behaviour of square-pyramidal Co(II)5 aggregates: tuning SMM behaviour through variations in the ligand shell.

Science.gov (United States)

Klöwer, Frederik; Lan, Yanhua; Nehrkorn, Joscha; Waldmann, Oliver; Anson, Christopher E; Powell, Annie K

2009-07-27

Three new mu4-bridged Co(II)5 clusters with similar core motifs have been synthesised with the use of N-tert-butyldiethanolamine (tbdeaH2) and pivalic acid (piv): [Co(II)5(mu4-N3)(tbdea)2(mu-piv)4(piv)(CH3CN)2].CH3CN (1), [Co(II)5(mu4-Cl)(Cl)(tbdea)2(mu-piv)4(pivH)2] (2) and [Co(II)5(mu4-N3)(Cl)(tbdea)2(mu-piv)4(pivH)2] (3). Magnetic measurements were performed for all three compounds. It was found that while the chloride-bridged cluster 2 does not show an out-of-phase signal, which excludes single-molecule magnet (SMM) behaviour, the azide-bridged compounds 1 and 3 show out-of-phase signals as well as frequency dependence of the ac susceptibility, as expected for SMMs. We confirmed that 1 is a SMM with zero-field quantum tunnelling of the magnetisation at 1.8 K. Compound 3 is likely a SMM with a blocking temperature well below 1.8 K. We established a physical model to fit the chiT versus T and M versus B curves of the three compounds to reproduce the observed SMM trend. The analysis showed that small changes in the ligand shell modify not only the magnitude of exchange constants, but also affect the J and g matrices in a non-trivial way.

Thermodynamics of complexes formation by ITC in methanol/water = 9/1 (v/v) solution: A case study

Energy Technology Data Exchange (ETDEWEB)

Fisicaro, Emilia, E-mail: emilia.fisicaro@unipr.it [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Compari, Carlotta; Bacciottini, Franco; Contardi, Laura [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Carcelli, Mauro; Rispoli, Gabriele; Rogolino, Dominga [University of Parma, Department of Chemistry, Parco Area delle Scienze, 17/A, 43124 Parma (Italy)

2014-06-01

Graphical abstract: Integrase strand transfert inhibitors chelate the metal ions in the active site of HIV integrase. - Highlights: • Development of inhibitors acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN), requires optimizing the binding affinity to the target. • We have defined an experimental procedure for obtaining reliable thermodynamic data by ITC in methanol/water = 9/1 (v/v) as solvent. • Formation heats in mixed solvent of the complexes formed by a ligand, model of Raltegravir, with Mg(II), Mn(II), Co(II) and Zn(II) are here reported. - Abstract: Most enzymes that participate in the biochemistry of nucleic acids require divalent metal ion cofactors to promote activity. Development of potent inhibitors, acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN) and RNase H, hepatitis C virus polymerase and influenza endonuclease, requires optimizing the binding affinity to the target, which is dictated by the binding free energy composed of both enthalpic and entropic contributions. They can be obtained by using isothermal titration microcalorimetry. We have defined an experimental procedure for obtaining reliable thermodynamic data in methanol/water = 9/1 0.1 M KCl as solvent, used to overcome solubility problems. In this way we have measured the heats of formation of the complexes formed by N-(4-fluorobenzyl)-5-hydroxy-2-isopropyl-1-methyl-6-oxo-1, 6-dihydroxypyrimidine-4-carboxylate (HL, a model of Raltegravir, the antiretroviral drug produced by Merck and Co.), and a series of divalent metal ions of biological interest (Mg(II), Mn(II), Co(II) and Zn(II)), whose speciation was previously determined by potentiometry.

Synthesis of Substituted Oxo-Azepines by Regio- and Diastereoselective Hydroxylation

Directory of Open Access Journals (Sweden)

Harold Spedding

2017-10-01

Full Text Available Substituted seven-membered N-heterocycles are prevalent bioactive epitopes and useful synthons for preparing enzyme inhibitors or molecular recognition systems. To fully exploit the chemical properties of this flexible N-heterocycle scaffold, efficient methods for its diverse functionalization are required. Here we utilize the late-stage oxidation of tetrahydroazepines as an approach to access densely functionalized oxo-azepines in a total of 8 steps and ~30% overall yield from commercially available starting materials. Hydroboration of tetrahydroazepines proceeded with diastereoselectivity in a substrate-dependent manner to yield regioisomeric azepanols before their oxidation to the corresponding oxo-azepines. Regioselectivity of the hydroboration step may be improved moderately by a rhodium catalyst, albeit with loss of conversion to a competing hydrogenation pathway. Overall our method allows efficient access to azepanols and oxo-azepines as versatile epitopes and synthons with a high degree of diastereoselectivity and moderate regioselectivity.

Application of Some Synthesized Polymeric Composite Resins for Removal of Some Metal Ions

International Nuclear Information System (INIS)

El-Zahhhar, A.A.; Abdel-Aziz, H.M.; Siyam, T.

2005-01-01

The ion-exchange and sorption characteristic of new polymeric composite resins, prepared by gamma radiation were experimentally studied. The composite resins shows high uptake for Co(II) and Eu(III) ions in aqueous solutions in wide range of ph. The selectivity of the resins to Co (II) or Eu (III) species in the presence of some competing ions and complexing agents (as Na + , Fe 3+ , EDTA Na 2 , etc.) was compared. Various factors that could affect the sorption behaviors of metal ions (Co (II) and Eu (III)) on the prepared polymeric composite resins were studied such as ionic strength, Contact time, volume mass ratio

8-Oxo-7,8-dihydroadenine and 8-Oxo-7,8-dihydroadenosine-Chemistry, Structure, and Function in RNA and Their Presence in Natural Products and Potential Drug Derivatives.

Science.gov (United States)

Choi, Yu Jung; Chang, Stephanie J; Gibala, Krzysztof S; Resendiz, Marino J E

2017-05-17

A description and history of the role that 8-oxo-7,8-dihydroadenine (8-oxoAde) and 8-oxo-7,8-dihydroadenosine (8-oxoA) have in various fields has been compiled. This Review focusses on 1) the formation of this oxidatively generated modification in RNA, its interactions with other biopolymers, and its potential role in the development/progression of disease; 2) the independent synthesis and incorporation of this modified nucleoside into oligonucleotides of RNA to display the progress that has been made in establishing its behavior in biologically relevant systems; 3) reported synthetic routes, which date back to 1890, along with the progress that has been made in the total synthesis of the nucleobase, nucleoside, and their corresponding derivatives; and 4) the isolation, total synthesis, and biological activity of natural products containing these moieties as the backbone. The current state of research regarding this oxidatively generated lesion as well as its importance in the context of RNA, natural products, and potential as drug derivatives is illustrated using all available examples reported to date. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Titanium oxo-clusters: precursors for a Lego-like construction of nanostructured hybrid materials.

Science.gov (United States)

Rozes, Laurence; Sanchez, Clément

2011-02-01

Titanium oxo-clusters, well-defined monodispersed nano-objects, are appropriate nano-building blocks for the preparation of organic-inorganic materials by a bottom up approach. This critical review proposes to present the different structures of titanium oxo-clusters referenced in the literature and the different strategies followed to build up hybrid materials with these versatile building units. In particular, this critical review cites and reports on the most important papers in the literature, concentrating on recent developments in the field of synthesis, characterization, and the use of titanium oxo-clusters for the construction of advanced hybrid materials (137 references).

LC-ESI-MS/MS on an ion trap for the determination of LSD, iso-LSD, nor-LSD and 2-oxo-3-hydroxy-LSD in blood, urine and vitreous humor.

Science.gov (United States)

Favretto, Donata; Frison, Giampietro; Maietti, Sergio; Ferrara, Santo Davide

2007-07-01

A method has been developed for the simultaneous determination of lysergic acid diethylamide (LSD), its epimer iso-LSD, and its main metabolites nor-LSD and 2-oxo-3-hydroxy LSD in blood, urine, and, for the first time, vitreous humor samples. The method is based on liquid/liquid extraction and liquid chromatography-multiple mass spectrometry detection in an ion trap mass spectrometer, in positive ion electrospray ionization conditions. Five microliter of sample are injected and analysis time is 12 min. The method is specific, selective and sensitive, and achieves limits of quantification of 20 pg/ml for both LSD and nor-LSD in blood, urine, and vitreous humor. No significant interfering substance or ion suppression was identified for LSD, iso-LSD, and nor-LSD. The interassay reproducibilities for LSD at 20 pg/ml and 2 ng/ml in urine were 8.3 and 5.6%, respectively. Within-run precision using control samples at 20 pg/ml and 2 ng/ml was 6.9 and 3.9%. Mean recoveries of two concentrations spiked into drug free samples were in the range 60-107% in blood, 50-105% in urine, and 65-105% in vitreous humor. The method was successfully applied to the forensic determination of postmortem LSD levels in the biological fluids of a multi drug abuser; for the first time, LSD could be detected in vitreous humor.

Nomenclature on an inorganic compound

International Nuclear Information System (INIS)

1998-10-01

This book contains eleven chapters : which mention nomenclature of an inorganic compound with introduction and general principle on nomenclature of compound. It gives the description of grammar for nomenclature such as brackets, diagonal line, asterisk, and affix, element, atom and groups of atom, chemical formula, naming by stoichiometry, solid, neutral molecule compound, ion, a substituent, radical and name of salt, oxo acid and anion on introduction and definition of oxo acid, coordination compound like symbol of stereochemistry , boron and hydrogen compound and related compound.

Crystal structure of a dinuclear CoII complex with bridging fluoride ligands: di-μ-fluorido-bis{tris[(6-methylpyridin-2-ylmethyl]amine}dicobalt(II bis(tetrafluoridoborate

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Masataka Inomata

2014-11-01

Full Text Available Reaction of Co(BF42·6H2O with tris[(6-methylpyridin-2-ylmethyl]amiine in methanol results in a fluoride abstraction from BF4−, yielding the unexpected title compound, [Co2F2(C21H24N42](BF42. The complex cation consists of two inversion-related [Co(C21H24N4]2+ moieties bridged by a pair of fluoride ligands. The CoII cation is six-coordinated in a distorted octahedral geometry and forms a +II high-spin state. In the crystal, the complex cation and the BF4− anion are connected by C—H...F hydrogen bonds, forming a three-dimensional network. An intramolecular C—H...F hydrogen bond is also observed.

Potent PPARα activator derived from tomato juice, 13-oxo-9,11-octadecadienoic acid, decreases plasma and hepatic triglyceride in obese diabetic mice.

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Young-il Kim

Full Text Available Dyslipidemia is a major risk factor for development of several obesity-related diseases. The peroxisome proliferator-activated receptor α (PPARα is a ligand-activated transcription factor that regulates energy metabolism. Previously, we reported that 9-oxo-10,12-octadecadienoic acid (9-oxo-ODA is presented in fresh tomato fruits and acts as a PPARα agonist. In addition to 9-oxo-ODA, we developed that 13-oxo-9,11-octadecadienoic acid (13-oxo-ODA, which is an isomer of 9-oxo-ODA, is present only in tomato juice. In this study, we explored the possibility that 13-oxo-ODA acts as a PPARα agonist in vitro and whether its effect ameliorates dyslipidemia and hepatic steatosis in vivo. In vitro luciferase assay experiments revealed that 13-oxo-ODA significantly induced PPARα activation; moreover, the luciferase activity of 13-oxo-ODA was stronger than that of 9-oxo-ODA and conjugated linoleic acid (CLA, which is a precursor of 13-oxo-ODA and is well-known as a potent PPARα activator. In addition to in vitro experiment, treatment with 13-oxo-ODA decreased the levels of plasma and hepatic triglycerides in obese KK-Ay mice fed a high-fat diet. In conclusion, our findings indicate that 13-oxo-ODA act as a potent PPARα agonist, suggesting a possibility to improve obesity-induced dyslipidemia and hepatic steatosis.

Defect-induced luminescence in sol-gel silica samples doped with Co(II) at different concentrations

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Sandoval, S. [Centro de Investigacion y Estudios Avanzados, Queretaro, Apdo. Postal 1-798, Queretaro, Qro. 76001 (Mexico); Estevez, M. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico); Pacheco, S. [Instituto Mexicano del Petroleo, Av. 100 metros (Mexico); Vargas, S. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico); Rodriguez, R. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico)], E-mail: rogelior@servidor.unam.mx

2007-12-20

The defect-induced luminescence properties of silica samples prepared by the sol-gel method and doped with Co(II) are reported. Silica monoliths doped with different concentrations of Co(II) were laser irradiated (He-Ne 632.8 nm) producing fluorescence. However, this fluorescence is exponentially reduced with the irradiation time, to practically disappear. The rate the fluorescence decays can be well modeled with a double exponential function of the irradiation time, containing two different relaxation times; a baseline is also required to take into account some residual fluorescence. The characteristic times involved in this luminescence quenching process are in the range of seconds. This luminescence suppression can be associated to the local heating produced by the laser irradiation when focused in a small area (2 {mu}m in diameter) on the sample. This heating process reduces physical (grain boundaries, surface states) and chemical (oxygen vacancies produced by the dopant) defects in the sample.

Understanding the nitrate coordination to Eu3+ ions in solution by potential of mean force calculations

International Nuclear Information System (INIS)

Duvail, M.; Guilbaud, Ph.

2011-01-01

Coordination of nitrate anions with lanthanoid cations (Ln 3+ ) in water, methanol and octanol-1 has been studied by means of molecular dynamics simulations with explicit polarization. Potential of mean force (PMF) profiles have been calculated for a mono-complex of lanthanoid nitrate (Ln(NO 3 ) 2+ ) in these solvents using umbrella-sampling molecular dynamics. In pure water, no difference in the nitrato coordination to lanthanoids (Nd 3+ , Eu 3+ and Dy 3+ ) is observed, i.e. the nitrate anion prefers the monodentate coordination, which promotes the salt dissociation. Then, the influence of the nature of the solvating molecules on the nitrato coordination to Eu 3+ has been investigated. PMF profiles point out that both monodentate and bidentate coordinations are stable in neat methanol, while in neat octanol, only the bidentate one is. MD simulations of Eu(NO 3 ) 3 in water-octanol mixtures with different concentrations of water have been then performed and confirm the importance of the water molecules' presence on the nitrate ion's coordination mode. (authors)

COII ”long fragment” reliability in characterisation and classification of forensically important flies

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Sanaa M. Aly

2017-01-01

Full Text Available Introduction : Molecular identification of collected flies is important in forensic entomological analysis guided with accurate evaluation of the chosen genetic marker. The selected mitochondrial DNA segments can be used to properly identify species. The aim of the present study was to determine the reliability of the 635-bp-long cytochrome oxidase II gene (COII in identification of forensically important flies. Material and methods: Forty-two specimens belonging to 11 species ( Calliphoridae: Chrysomya albiceps , C. rufifacies , C. megacephala , Lucilia sericata , L. cuprina ; Sarcophagidae: Sarcophaga carnaria , S. dux , S. albiceps , Wohlfahrtia nuba ; Muscidae: Musca domestica , M. autumnalis were analysed. The selected marker was amplified using PCR followed by sequencing. Nucleotide sequence divergences were calculated using the K2P (Kimura two-parameter distance model, and a NJ (neighbour-joining phylogenetic tree was constructed. Results : All examined specimens were assigned to the correct species, formed distinct monophyletic clades and ordered in accordance with their taxonomic classification. Intraspecific variation ranged from 0 to 1% and interspecific variation occurred between 2 and 20%. Conclusions : The 635-bp-long COII marker is suitable for clear differentiation and identification of forensically relevant flies.

Syntheses, Magnetic and Spectral Studies on the Coordination Compounds of the Polystyrene-anchored Thiazolidin-4-one

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Dinesh Kumar

2012-01-01

Full Text Available The reaction between polystyrene 3-formylsalicylate and thiophene-2-carboxylic acid hydrazide in DMF in the presence of ethyl acetate results in the formation of polystyrene N-(2-carbamoylthienyl-3'-carboxy-2'-hydroxybenzylideneimine (I. A benzene suspension of I reacts with mercaptoacetic acid and forms the polystyrene N-(2-carbamoylthienyl-C-(3'-carboxy-2'-hydroxyphenyl thiazolidin-4-one, PSCH2–LH2 (II. A DMF suspension of II reacts with Zn(II, Co(II, Cu(II, Zr(OH2(IV and MoO2(VI ions and forms the corresponding polystyrene-anchored coordination compounds, [PSCH2–LZn(DMF] (III, [PSCH2–LCo(DMF3] (IV, [PSCH2–LHCu(OAc] (V, [PSCH2–LH2Zr(OH2(OAc2] (VI and [PSCH2–LHMoO2(acac] (VII respectively. The polystyrene-anchored coordination compounds have been characterized on the basis of elemental analyses, spectral (IR, reflectance, ESR studies and magnetic susceptibility measurements. II acts as a neutral tridentate ONS donor ligand in VI, a monobasic bidentate OS donor ligand in VII, a monobasic tridentate ONS donor ligand in V and a dibasic tridentate ONO donor ligand in III and IV. The acetato groups behave as monodentate ligands in V and VI. A square-planar structure for V, a tetrahedral structure for III, an octahedral structure for IV and VII and a pentagonal-bipyramidal structure for VI are suggested.

Synthesis and spectroscopic studies of biologically active tetraazamacrocyclic complexes of Mn(II, Co(II, Ni(II, Pd(II and Pt(II

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Monika Tyagi

2014-01-01

Full Text Available Complexes of Mn(II, Co(II, Ni(II, Pd(II and Pt(II were synthesized with the macrocyclic ligand, i.e., 2,3,9,10-tetraketo-1,4,8,11-tetraazacycoletradecane. The ligand was prepared by the [2 + 2] condensation of diethyloxalate and 1,3-diamino propane and characterized by elemental analysis, mass, IR and 1H NMR spectral studies. All the complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, IR, electronic and electron paramagnetic resonance spectral studies. The molar conductance measurements of Mn(II, Co(II and Ni(II complexes in DMF correspond to non electrolyte nature, whereas Pd(II and Pt(II complexes are 1:2 electrolyte. On the basis of spectral studies an octahedral geometry has been assigned for Mn(II, Co(II and Ni(II complexes, whereas square planar geometry assigned for Pd(II and Pt(II. In vitro the ligand and its metal complexes were evaluated against plant pathogenic fungi (Fusarium odum, Aspergillus niger and Rhizoctonia bataticola and some compounds found to be more active as commercially available fungicide like Chlorothalonil.

Chemistry of oxovanadium(IV) bound to tetradentate ONNO donors; influence of axial coordination on the V-Osub(1) bond

International Nuclear Information System (INIS)

Maity, A.; Ghosh, S.

1992-01-01

Chelating behaviour of some tetradentate ONNO donors from q-aminobenzoylhydrazide and some diketones towards oxo-vanadium(IV) ion is reported. The donors react with oxometal cation depending on the pH of the reaction medium. The product containing the neutral keto and the binegative enol form of the donor have the formulae [Vo(H 2 L)(SO 4 )](at pH 3.0)(1) and [VO(L)(H 2 O)] (at pH 6.0) (2) respectively [H 2 L=(2-NH 2 )C 6 H 4 CONH: C(R).(CH 2 ) m C(R) : NNH CO.C 6 H 4 (2-NH 2 ); H 2 L=H 2 DA(R=CH 3 , m=0), H 2 BA(R=C 6 H 5 , m=0), H 2 AA(R=CH 3 , m=2)]. Both (1) and (2) react with a neutral monodentate donor B(B=pyridine, aniline etc.) yielding mixed-ligand complexes [VO(L)(B)]. Influence of the axial coordination on the V-Osub((1)) bond is discussed and a monomeric distorted octahedral donor environment for the oxovanadium(IV) ion has been suggested. (author). 2 refs., 2 tabs., 3 figs

Structural and magnetic characterization of mixed valence Co(II, III)xZn1−xO epitaxial thin films

International Nuclear Information System (INIS)

Negi, D.S.; Loukya, B.; Dileep, K.; Sahu, R.; Shetty, S.; Kumar, N.; Ghatak, J.; Pachauri, N.; Gupta, A.; Datta, R.

2014-01-01

In this article, we report on the Co atom incorporation, secondary phase formation and composition-dependent magnetic and optical properties of mixed valence Co(II, III) x Zn 1−x O epitaxial thin films grown by pulsed laser deposition. The intended total Co concentration is varied between ∼6–60 at.% with relatively higher concentration of +3 over +2 charge state. Mixed valence Co(II, III) shows high solubility in ZnO (up to 38 at.%) and ferromagnetism is observed in samples with total Co incorporation of ∼29 and 38 at.%. Electron diffraction pattern and high resolution transmission electron microscopy images reveal single crystalline nature of the thin films with wurtzite structure. Co oxide interlayer, with both rock salt and spinel structure, are observed to be formed between the substrate and wurtzite film for total Co concentration at ∼17 at.% and above. Magnetization shows composition dependence with a saturation moment value of ∼93 emu cm −3 and a coercive field of ∼285 Oe observed for ∼38 at.% Co:ZnO films. Ferromagnetism was not observed for films with Co concentration 17 and 9 at.%. The Co oxide interlayer does not show any ferromagnetism. All the films are n-type with carrier concentration ∼10 19 cm −3 . The observed magnetism is probably resulting from direct antiferromagntic exchange interaction between Co 2+ and Co 3+ ions favored by heavy Co alloying giving rise to ferrimagnetism in the system. - Highlights: • Mixed valence Co doped ZnO ferromagnetic single crystal thin film. • Secondary phase formation in terms of CoO and Co3O4 and magnetism is observed only for high Co alloying. • Cathodoluminescence (CL) data showing increase in band gap with Co concentrations

Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

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José Maria Rodrigues da Luz

Full Text Available In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2 concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.

Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.

Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process. PMID:25419675

Developmental changes in rat liver branched-chain 2-oxo acid dehydrogenase.

OpenAIRE

May, E E; May, M E; Aftring, R P; Buse, M G

1982-01-01

Branched-chain 2-oxo acid dehydrogenase catalyses the first irreversible step in the degradation of the branched-chain amino acids leucine, isoleucine and valine. With specifically labelled 4-methyl-2-oxo[1-14C]pentanoate as substrate, the enzyme's activity was measured in rat liver homogenates. Activity (per g wet wL of liver or per mg of protein) increased most rapidly during the perinatal period (2 days before to 1 day after birth), reaching approximately adult values by the time of weanin...

Steric control of redox events in organo-uranium chemistry: synthesis and characterisation of U(V) oxo and nitrido complexes

OpenAIRE

Tsoureas, Nikolaos; Kilpatrick, Alexander; Inman, Christopher; Cloke, Frederick Geoffrey

2016-01-01

The synthesis and molecular structures of a U(V) neutral terminal oxo complex and a U(V) sodium uranium nitride contact ion pair are described. The synthesis of the former is achieved by the use of tBuNCO as a mild oxygen transfer reagent, whilst that of the latter is via the reduction of NaN3. Both mono-uranium complexes are stabilised by the presence of bulky silyl substituents on the ligand framework that facilitate a 2e- oxidation of a single U(III) centre. In contrast, when steric hindra...

Distinct energetics and closing pathways for DNA polymerase β with 8-oxoG template and different incoming nucleotides

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Wang Yanli

2007-02-01

Full Text Available Abstract Background 8-Oxoguanine (8-oxoG is a common oxidative lesion frequently encountered by DNA polymerases such as the repair enzyme DNA polymerase β (pol β. To interpret in atomic and energetic detail how pol β processes 8-oxoG, we apply transition path sampling to delineate closing pathways of pol β 8-oxoG complexes with dCTP and dATP incoming nucleotides and compare the results to those of the nonlesioned G:dCTP and G:dATPanalogues. Results Our analyses show that the closing pathways of the 8-oxoG complexes are different from one another and from the nonlesioned analogues in terms of the individual transition states along each pathway, associated energies, and the stability of each pathway's closed state relative to the corresponding open state. In particular, the closed-to-open state stability difference in each system establishes a hierarchy of stability (from high to low as G:C > 8-oxoG:C > 8-oxoG:A > G:A, corresponding to -3, -2, 2, 9 kBT, respectively. This hierarchy of closed state stability parallels the experimentally observed processing efficiencies for the four pairs. Network models based on the calculated rate constants in each pathway indicate that the closed species are more populated than the open species for 8-oxoG:dCTP, whereas the opposite is true for 8-oxoG:dATP. Conclusion These results suggest that the lower insertion efficiency (larger Km for dATP compared to dCTP opposite 8-oxoG is caused by a less stable closed-form of pol β, destabilized by unfavorable interactions between Tyr271 and the mispair. This stability of the closed vs. open form can also explain the higher insertion efficiency for 8-oxoG:dATP compared to the nonlesioned G:dATP pair, which also has a higher overall conformational barrier. Our study offers atomic details of the complexes at different states, in addition to helping interpret the different insertion efficiencies of dATP and dCTP opposite 8-oxoG and G.

Structural, theoretical and corrosion inhibition studies on some transition metal complexes derived from heterocyclic system

Science.gov (United States)

Gupta, Shraddha Rani; Mourya, Punita; Singh, M. M.; Singh, Vinod P.

2017-06-01

A Schiff base, (E)-N‧-((1H-indol-3-yl)methylene)-2-aminobenzohydrazide (Iabh) and its Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. These compounds have been characterized by different physico-chemical and spectroscopic tools (UV-Vis, IR, NMR and ESI-Mass). The molecular structure of Iabh is determined by single crystal X-ray diffraction technique. The ligand Iabh displays E-configuration about the >Cdbnd N- bond. The structure of ligand is stabilized by intra-molecular H-bonding. In all the metal complexes the ligand coordinates through azomethine-N and carbonyl-O resulting a distorted octahedral geometry for Mn(II), Co(II) and Cu(II) complexes in which chloride ions occupy axial positions. Ni(II) and Zn(II) complexes, however, form 4-coordinate distorted square planer and tetrahedral geometry around metal ion, respectively. The structures of the complexes have been satisfactorily modeled by calculations based on density functional theory (DFT) and time dependent-DFT (TD-DFT). The corrosion inhibition study of the compounds have been performed against mild steel in 0.5 M H2SO4 solution at 298 K by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). They show appreciable corrosion inhibition property.

NMR structural studies of the ionizing radiation adduct 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) opposite deoxyadenosine in a DNA duplex. 8-oxo-7H-dG(syn)·dA(anti) alignment at lesion site

International Nuclear Information System (INIS)

Kouchakdjian, M.; Patel, D.J.; Bodepudi, V.; Shibutani, S.; Eisenberg, M.; Johnson, F.; Grollman, A.P.

1991-01-01

Proton NMR studies are reported on the complementary d(C1-C2-A3-C4-T5-A6-oxo-G7-T8-C9-A10-C11-C12)·d(G13-G14-T15-G16-A17-A18-T19-A20-G21-T22-G23-G24) dodecanucleotide duplex (designated 8-oxo-7H-dG·dA 12-mer), which contains a centrally located 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) residue, a group commonly found in DNA that has been exposed to ionizing radiation or oxidizing free radicals. From the NMR spectra it can be deduced that this moiety exists as two tautomers, or gives rise to two DNA conformations, that are in equilibrium and that exchange slowly. The present study focuses on the major component of the equilibrium that originates in the 6,8-dioxo tautomer of 8-oxo-7H-dG. The authors have assigned the exchangeable NH1, NH7, and NH 2 -2 base protons located on the Watson-Crick and Hoogsteen edges of 8-oxo-7H-dG7 in the 8-oxo-7H-dG·dA 12-mer duplex, using an analysis of one- and two-dimensional nuclear Overhauser enhancement (NOE) data in H 2 O solution. They were able to detect a set of intra- and interstrand NOEs between protons (exchangeable and nonexchangeable) on adjacent residues in the d(A6-oxo-G7-T8)·d(A17-A18-T19) trinucleotide segment centered about the lesion site that establishes stacking of the oxo-dG7(syn)·dA(anti) pair between stable Watson-Crick dA6·dT19 and dT8·A17 base pairs with minimal perturbation of the helix. The structural studies demonstrate that 8-oxo-7H-dG(syn)·dA(anti) forms a stable pair in the interior of the helix, providing a basis for the observed incorporation of dA opposite 8-oxo-7H-dG when readthrough occurs past this oxidized nucleoside base

Subtle interactions and electron transfer between U{sup III}, Np{sup III}, or Pu{sup III} and uranyl mediated by the oxo group

Energy Technology Data Exchange (ETDEWEB)

Arnold, Polly L.; Zegke, Markus; Hollis, Emmalina; Pecharman, Anne-Frederique; Love, Jason B. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom); Dutkiewicz, Michal S. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom); European Commission, Directorate for Nuclear Safety and Security, Joint Research Centre, Karlsruhe (Germany); Walter, Olaf; Apostolidis, Christos; Magnani, Nicola; Griveau, Jean-Christophe; Colineau, Eric; Caciuffo, Roberto [European Commission, Directorate for Nuclear Safety and Security, Joint Research Centre, Karlsruhe (Germany); Zhang, Xiaobin; Schreckenbach, Georg [Department of Chemistry, University of Manitoba, Winnipeg, MB (Canada)

2016-10-04

A dramatic difference in the ability of the reducing An{sup III} center in AnCp{sub 3} (An=U, Np, Pu; Cp=C{sub 5}H{sub 5}) to oxo-bind and reduce the uranyl(VI) dication in the complex [(UO{sub 2})(THF)(H{sub 2}L)] (L=''Pacman'' Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp{sub 3}U forms the U{sup IV}-uranyl(V) compound that behaves as a U{sup V}-localized single molecule magnet below 4 K. The extent of reduction by the Cp{sub 3}Np group upon oxo-coordination is much less, with a Np{sup III}-uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np{sup IV}U{sup V} but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np{sup III}-U{sup VI} assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu{sup III}-U{sup VI} interaction is too weak to be observed in THF solvent, in agreement with calculated predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Calculation of energetic characteristics of 3d-transition metal ion aquacomplexes in tetrahedral and octahedral coordination by broadened Hukkel method

International Nuclear Information System (INIS)

Zhogolev, D.A.; Bunyatyan, B.Kh.; Yatsimirskij, K.B.

1975-01-01

Aquacomplexes formation energies of bi- and trivalent ions of 3d transition metals from Sc to Ni in the tetrahedral and octahedral coordinations have been calculated to compare their energetic advantages. Unlike ions of alkali metals and halogens, a tendency for higher or at least equal energetic effect of the formation of a tetrahedral complex, compared to octahedral, is characteristic of the ions under study. This can be explained by an increase in the covalency degree of the bond ion-ligand and by a considerable charge transfer from ligands to the central ion in the case of transition elements

Synthesis and structural evaluation of five coordination complexes of benzenepentacarboxylic acid with aza-donor ligands

Science.gov (United States)

Shimpi, Manishkumar R.; Biswas, Sharmita Nandy; Sarkar, Sohini; Pedireddi, V. R.

2016-06-01

Synthesis and structural features of five new coordination assemblies, [Co(bpyH)(H2O)5](BPCH)·(bpyH2)0.5·(H2O) (1a), [{Cu(H2O)3}·{Cu0.5(bpy)0.5(H2O)0.5}2(μ-BPCH)] (1b), [{Cd0.5(BPCH)}2·{Cd0.5(bpy)(H2O)2}2]·6(H2O) (1c), [Cu(BPCH2)(bpyeaH)]·2(H2O) (1d) and [Cd2 (bpyea)0.5(oxalate)0.5(μ-BPC) (H2O)]·(bpyeaH2)·2(H2O) (1e), have been reported. All the assemblies were prepared by co-crystallization of benzenepentacarboxylic acid (BPCH5) either with 4,4‧-bipyridine (bpy) or 1,2-bis(4-pyridyl)ethane (bpyea) in the presence of a transition metal ion (either Co(II), Cu(II) or Cd(II)) as the case may be. All the five compounds were synthesized by hydrothermal method and structures were determined by single crystal X-ray diffraction. All the obtained compounds, 1a-1e, exhibit distinct 3-D polymeric architectures either in the form of stacked layers or host-guest networks in which water molecules play a pivotal role providing additional stabilization by coordinate bonds as well as hydrogen bonds. Other non-covalent interactions such as C-H … π and π … π stacking also participate in the formation of exotic 3-D structures of these complexes.

Coordination Nature of 4-Mercaptoaniline to Sn(II Ion: Formation of a One Dimensional Coordination Polymer and Its Decomposition to a Mono Nuclear Sn(IV Complex

Directory of Open Access Journals (Sweden)

Eon S. Burkett

2014-12-01

Full Text Available The coordination of the bifunctional ligand 4-mercaptoaniline with aqueo us tin(II metal ion was studied. A coordination polymer was synthesized when an aqueous solution of SnCl2 was treated with 4-MA. The crystalline material is stable under atmospheric conditions retaining its oxidation state. However, when submerged in a solution saturated with oxygen, the compound oxidizes to a mononuclear tin(IV complex. Both the compounds were characterized by single crystal X-ray diffraction studies. Although the structure of the tin(IV complex was previously reported, crystal structure of this compound was redetermined.

Siting and Distribution of the Co Ions in Beta Zeolite: A UV-Vis-NIR and FTIR Study

Czech Academy of Sciences Publication Activity Database

Dědeček, Jiří; Čapek, Libor; Kaucký, Dalibor; Sobalík, Zdeněk; Wichterlová, Blanka

2002-01-01

Roč. 211, č. 1 (2002), s. 198-207 ISSN 0021-9517 R&D Projects: GA MŠk OC D15.20; GA ČR GA104/00/0640 Institutional research plan: CEZ:AV0Z4040901 Keywords : Co-beta * Co(II) ions * cation siting Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.118, year: 2002

Use of the cation exchange equilibrium method for the determination of stability constants of Co(II) with soil humic and fulvic acids

International Nuclear Information System (INIS)

Du, J.Z.; Zhou, C.Y.; Dong, W.M.; Tao, Z.Y.

1999-01-01

The stability constants for tracer concentrations of Co(II) complexes with both the red earth humic and fulvic acids were determined at pH 5.9 and ionic strength 0.010 mol/l by using the ARDAKANI-STEVENSON cation exchange equilibrium method and the radiotracer 60 Co. It was found that the 1:1 complexes of Co(II) with the red earth humic and fulvic acids were formed and that the average values of logβ (stability constant) of humic and fulvic acid complexes were 5.76±0.19 and 4.42±0.03, respectively. (author)

Contribution to the coordination chemistry of penta, hexa and heptavalent ions of 5f elements

International Nuclear Information System (INIS)

Musikas, Claude.

1978-01-01

This report has two main parts in which are discussed results dealing with: - aquo and hydroxo complexes of penta, hexa and heptavalent ions of 5f elements - pseuso halides complexes of these ions (SCN - , N 3 - , CN - ). It has been shown, by spectrophotometric and electrochemical measurements that U (V) possesses an aquo ion more acid than the known UO 2 + ion. This form is observed as insoluble hydroxid near pH 3.0 or as soluble polynuclear hydroxo complexes at lower pH. Hydroxo anionic complexes of U (VI) have been observed and one can precise the mecanism of hydrolysis of UO 2 ++ ions beyond he hydroxid UO 2 (OH) 2 . At pH 9 to 12, polynuclear species with low negative charge have been observed. At pH 13, others OH - ions enter in the coordination sphere of UO 2 ++ and mononuclear species are obtained. Reduction of polynuclear species leads to mixed hydroxo complexes of 'blue type'. Studies of hydrolysis of NpO 2 + allow to propose an hydrolysis mechanism similar to UO 2 ++ one. With electrochemical methods that in acidic media Np (VII) is present as NpO 3 + ions. Solubility product of NpO 3 OH has been measured. The second part is devoted to pseudohalides complexes of UO 2 ++ , UO 2 + and NpO 2 + ions [fr

Urinary excretion of 8-oxo-7,8-dihydroguanine as biomarker of oxidative damage to DNA

DEFF Research Database (Denmark)

Loft, Steffen; Danielsen, Pernille Høgh; Løhr, Mille

2012-01-01

to air pollution, toxic metals, tobacco smoke and low plasma antioxidant levels, whereas fruit and vegetable intake or dietary interventions showed no association. In rodent studies some types of feed may be source of 8-oxoGua in collected urine. Of cancer therapies, cisplatin increased 8-oxo...

One step synthesis of 6-oxo-cholestan-3β,5α-diol

International Nuclear Information System (INIS)

Voisin, Maud; Silvente-Poirot, Sandrine; Poirot, Marc

2014-01-01

Highlights: • Cholesterol-5,6-epoxides are metabolized into cholestane-3β,5α,6β-triol (CT) in cancer cells. • 6-Oxo-cholestan-3β,5α-diol (OCDO) is a putative metabolite of CT. • The one step syntheses of CT and OCDO from cholesterol are reported. • The one step syntheses of labelled CT and OCDO are reported. - Abstract: Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [ 14 C]-cholestane-3β,5α,6β-triol and [ 14 C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [ 14 C]-cholestane-3β,5α,6β-triol and [ 14 C]-6-oxo-cholestan-3β,5α-diol by oxidation of [ 14 C]-cholesterol with iodide metaperiodate (HIO 4 )

Investigation of the lithium ion mobility in cyclic model compounds and their ion conduction properties

Energy Technology Data Exchange (ETDEWEB)

Thielen, Joerg

2011-07-27

combination to changes in glass transition temperatures. Though the glass transition temperatures of the blends are low, their conductivities are only in the range of typical polymer electrolytes. The highest {sigma}{sub dc} obtained at ambient temperatures was 6.0 x 10{sup -6} S.cm{sup -1}, strongly suggesting a rather tight coordination of the lithium ions to the solvating 2-oxo-1,3-dioxolane moieties, supported by the increased {sigma}{sub dc} values for the oligo(ethylene oxide) based analogues. Further insights into the mechanism of lithium ion dynamics were derived from {sup 7}Li and {sup 13}C Solid-State NMR investigations. While localized ion motion was probed by i.e. {sup 7}Li spinlattice relaxation measurements with apparent activation energies E{sub a} of 20 to 40 kJ/mol, long-range macroscopic transport was monitored by Pulsed-Field Gradient (PFG) NMR, providing an E{sub a} of 61 kJ/mol. The latter is in good agreement with the values determined from bulk conductivity data, indicating the major contribution of ion transport was only detected by PFG NMR. However, the {mu}m-diffusion is rather slow, emphasizing the strong lithium coordination to the carbonyl oxygens, which hampers sufficient ion conductivities and suggests exploring 'softer' solvating moieties in future electrolytes.

Residue Phe112 of the Human-Type Corrinoid Adenosyltransferase (PduO) Enzyme of Lactobacillus reuteri Is Critical to the Formation of the Four-Coordinate Co(II) Corrinoid Substrate and to the Activity of the Enzyme

Energy Technology Data Exchange (ETDEWEB)

Mera, Paola E.; St. Maurice, Martin; Rayment, Ivan; Escalante-Semerena, Jorge C.; UW

2009-06-08

ATP:Corrinoid adenosyltransferases (ACAs) catalyze the transfer of the adenosyl moiety from ATP to cob(I)alamin via a four-coordinate cob(II)alamin intermediate. At present, it is unknown how ACAs promote the formation of the four-coordinate corrinoid species needed for activity. The published high-resolution crystal structure of the ACA from Lactobacillus reuteri (LrPduO) in complex with ATP and cob(II)alamin shows that the environment around the alpha face of the corrin ring consists of bulky hydrophobic residues. To understand how these residues promote the generation of the four-coordinate cob(II)alamin, variants of the human-type ACA enzyme from L. reuteri (LrPduO) were kinetically and structurally characterized. These studies revealed that residue Phe112 is critical in the displacement of 5,6-dimethylbenzimidazole (DMB) from its coordination bond with the Co ion of the ring, resulting in the formation of the four-coordinate species. An F112A substitution resulted in a 80% drop in the catalytic efficiency of the enzyme. The explanation for this loss of activity was obtained from the crystal structure of the mutant protein, which showed cob(II)alamin bound in the active site with DMB coordinated to the cobalt ion. The crystal structure of an LrPduO(F112H) variant showed a DMB-off/His-on interaction between the corrinoid and the enzyme, whose catalytic efficiency was 4 orders of magnitude lower than that of the wild-type protein. The analysis of the kinetic parameters of LrPduO(F112H) suggests that the F112H substitution negatively impacts product release. Substitutions of other hydrophobic residues in the Cbl binding pocket did not result in significant defects in catalytic efficiency in vitro; however, none of the variant enzymes analyzed in this work supported AdoCbl biosynthesis in vivo.

Synthesis, molecular structure, biological properties and molecular docking studies on Mn(II), Co(II) and Zn(II) complexes containing bipyridine-azide ligands.

Science.gov (United States)

Thamilarasan, Vijayan; Jayamani, Arumugam; Sengottuvelan, Nallathambi

2015-01-07

Metal complexes of the type Mn(bpy)2(N3)2 (1), Co(bpy)2(N3)2·3H2O (2) and Zn2(bpy)2(N3)4 (3) (Where bpy = 2,2-bipyridine) have been synthesized and characterized by elemental analysis and spectral (FT-IR, UV-vis) studies. The structure of complexes (1-3) have been determined by single crystal X-ray diffraction studies and the configuration of ligand-coordinated metal(II) ion was well described as distorted octahedral coordination geometry for Mn(II), Co(II) and distorted square pyramidal geometry for Zn(II) complexes. DNA binding interaction of these complexes (1-3) were investigated by UV-vis absorption, fluorescence circular dichroism spectral and molecular docking studies. The intrinsic binding constants Kb of complexes 1, 2 and 3 with CT-DNA obtained from UV-vis absorption studies were 8.37 × 10(4), 2.23 × 10(5) and 5.52 × 10(4) M(-1) respectively. The results indicated that the three complexes are able to bind to DNA with different binding affinity, in the order 2 > 1 > 3. Complexes (1-3) exhibit a good binding propensity to bovine serum albumin (BSA) proteins having relatively high binding constant values. Gel electrophoresis assay demonstrated the ability of the complexes 1-3 promote the cleavage ability of the pBR322 plasmid DNA in the presence of the reducing agent 3-mercaptopropionic acid (MPA) but with different cleavage mechanisms: the complex 3 cleaves DNA via hydrolytic pathway (T4 DNA ligase assay), while the DNA cleavage by complexes 1 and 2 follows oxidative pathway. The chemical nuclease activity follows the order: 2 > 1 > 3. The effects of various activators were also investigated and the nuclease activity efficacy followed the order MPA > GSH > H2O2 > Asc. The cytotoxicity studies of complexes 1-3 were tested in vitro on breast cancer cell line (MCF-7) and they found to be active. Copyright © 2014. Published by Elsevier Masson SAS.

Thermodynamic properties and cloud droplet activation of a series of oxo-acids

Directory of Open Access Journals (Sweden)

M. Frosch

2010-07-01

Full Text Available We have investigated the thermodynamic properties of four aliphatic oxo-dicarboyxlic acids identified or thought to be present in atmospheric particulate matter: oxosuccinic acid, 2-oxoglutaric acid, 3-oxoglutaric acid, and 4-oxopimelic acid. The compounds were characterized in terms of their cloud condensation nuclei (CCN activity, vapor pressure, density, and tendency to decarboxylate in aqueous solution. We deployed a variety of experimental techniques and instruments: a CCN counter, a Tandem Differential Mobililty Analyzer (TDMA coupled with a laminar flow-tube, and liquid chromatography/mass spectrometry (LC/MS. The presence of the oxo functional group in the α-position causes the vapor pressure of the compounds to diminish by an order of magnitude with respect to the parent dicarboxylic acid, while the CCN activity is similar or increased. Dicarboxylic acids with an oxo-group in the β-position decarboxylate in aqueous solution. We studied the effects of this process on our measurements and findings.

Need for reaction coordinates to ensure a complete basis set in an adiabatic representation of ion-atom collisions

Science.gov (United States)

Rabli, Djamal; McCarroll, Ronald

2018-02-01

This review surveys the different theoretical approaches, used to describe inelastic and rearrangement processes in collisions involving atoms and ions. For a range of energies from a few meV up to about 1 keV, the adiabatic representation is expected to be valid and under these conditions, inelastic and rearrangement processes take place via a network of avoided crossings of the potential energy curves of the collision system. In general, such avoided crossings are finite in number. The non-adiabatic coupling, due to the breakdown of the Born-Oppenheimer separation of the electronic and nuclear variables, depends on the ratio of the electron mass to the nuclear mass terms in the total Hamiltonian. By limiting terms in the total Hamiltonian correct to first order in the electron to nuclear mass ratio, a system of reaction coordinates is found which allows for a correct description of both inelastic channels. The connection between the use of reaction coordinates in the quantum description and the electron translation factors of the impact parameter approach is established. A major result is that only when reaction coordinates are used, is it possible to introduce the notion of a minimal basis set. Such a set must include all avoided crossings including both radial coupling and long range Coriolis coupling. But, only when reactive coordinates are used, can such a basis set be considered as complete. In particular when the centre of nuclear mass is used as centre of coordinates, rather than the correct reaction coordinates, it is shown that erroneous results are obtained. A few results to illustrate this important point are presented: one concerning a simple two-state Landau-Zener type avoided crossing, the other concerning a network of multiple crossings in a typical electron capture process involving a highly charged ion with a neutral atom.

Surface modification of materials by ion implantations for industrial and medical applications. Final report of a co-ordinated research project

International Nuclear Information System (INIS)

2000-07-01

The objectives of the Co-ordinated Research Project on Modification of Materials by Ion Treatment for Industrial Applications were to develop economically acceptable surface modification techniques leading to thick treated layers, to predict ion beam mixing and impurity atom migration during and after implantation, and to evaluate the tribological post-implantation properties and performance of treated components. This TECDOC summarises the current status and prospects in surface modification by ion implantation methodology and technology, providing new information in basic and applied research

Surface modification of materials by ion implantations for industrial and medical applications. Final report of a co-ordinated research project

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The objectives of the Co-ordinated Research Project on Modification of Materials by Ion Treatment for Industrial Applications were to develop economically acceptable surface modification techniques leading to thick treated layers, to predict ion beam mixing and impurity atom migration during and after implantation, and to evaluate the tribological post-implantation properties and performance of treated components. This TECDOC summarises the current status and prospects in surface modification by ion implantation methodology and technology, providing new information in basic and applied research.

Crystal structure of the salt bis(triethanolamine-κ4N,O,O′,O′′cadmium bis[2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-ylacetate

Directory of Open Access Journals (Sweden)

Jamshid Mengnorovich Ashurov

2016-04-01

Full Text Available The reaction of 2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-ylacetic acid (NBTA and triethanolamine (TEA with Cd(CH3OO2 resulted in the formation of the title salt, [Cd(C6H15NO32](C9H6NO3S2. In its crystal structure, the complex cation [Cd(TEA2]2+ and two independent NBTA− units with essentially similar geometries and conformations are present. In the complex cation, each TEA molecule behaves as an N,O,O′,O′′-tetradentate ligand, giving rise to an eight-coordinate CdII ion with a bicapped trigonal–prismatic configuration. All ethanol groups of each TEA molecule form three five-membered chelate rings around the CdII ion. The Cd—O and Cd—N distances are in the ranges 2.392 (2–2.478 (2 and 2.465 (2–2.475 (3 Å, respectively. O—H...O hydrogen bonds between the TEA hydroxy groups and carboxylate O atoms connect cationic and anionic moieties into chains parallel to [110]. Each NBTA− anion is additionally linked to a symmetry-related anion through π–π stacking interactions between the benzene and thiazoline rings [minimum centroid-to-centroid separation = 3.604 (2 Å]. Together with additional C—H...O interactions, these establish a double-layer polymeric network parallel to (001.

Recovery of metals from simulant spent lithium-ion battery as organophosphonate coordination polymers in aqueous media

Energy Technology Data Exchange (ETDEWEB)

Perez, Emilie; Andre, Marie-Laure; Navarro Amador, Ricardo [ICSM, Institut de Chimie Séparative de Marcoule, UMR 5257, CEA/CNRS/ENSCM/UM, Bât 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France); Hyvrard, François; Borrini, Julien [SARPI VEOLIA, Direction Technique et Innovations, Zone portuaire de Limay-Porcheville, 427 route du Hazay, 78520 Limay (France); Carboni, Michaël, E-mail: michael.carboni@cea.fr [ICSM, Institut de Chimie Séparative de Marcoule, UMR 5257, CEA/CNRS/ENSCM/UM, Bât 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France); Meyer, Daniel [ICSM, Institut de Chimie Séparative de Marcoule, UMR 5257, CEA/CNRS/ENSCM/UM, Bât 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France)

2016-11-05

Highlights: • Original waste disposal strategies for battery. • Precipitation of metals as coordination polymers. • Organo-phosphonate coordination polymers. • Selective extraction of manganese or co-precipitation of manganese/cobalt. • The recycling process give a promising application on any waste solution. - Abstract: An innovative approach is proposed for the recycling of metals from a simulant lithium-ion battery (LIBs) waste aqueous solution. Phosphonate organic linkers are introduced as precipitating agents to selectively react with the metals to form coordination polymers from an aqueous solution containing Ni, Mn and Co in a hydrothermal process. The supernatant is analyzed by ICP-AES to quantify the efficiency and the selectivity of the precipitation and the materials are characterized by Scanning Electron Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Thermogravimetric Analyses (TGA) and nitrogen gas sorption (BET). Conditions have been achieved to selectively precipitate Manganese or Manganese/Cobalt from this solution with a high efficiency. This work describes a novel method to obtain potentially valuable coordination polymers from a waste metal solution that can be generalized on any waste solution.

Complexes of vanadyl and uranyl ions with the chelating groups of humic matter

International Nuclear Information System (INIS)

Goncalves, M.L.S.; Mota, A.M.

1987-01-01

The uranyl and vanadyl complexes formed with salicylic, phthalic and 3,4-dihydroxybenzoic acids have been studied by potentiometry in order to determine the stability constants of the Msub(m) Lsub(n) species formed in solution, and the constants for hydrolysis and polymeric complexes, at 25.0 0 , in 0.10, 0.40 and 0.70M sodium perchlorate. MINIQUAD was used in process the data to find the best models for the species in solution, and calculate the formation constants. The uranyl-salicylic acid sytem was also studied by spectrophotometry and the program SQUAD used to process the data obtained. The best models for these systems show that co-ordination of the uranyl ion by carboxylate groups is easier than for the vanadyl ion, whereas the vanadyl ion seems to form more stable complexes with phenolate groups. Both oxo-cations seem to tend to hydrolyse rather than form complexes when the L:M ratios are greater than unity. Although the change in the constants with ionic strength is small, the activity coefficients of the salicylate and phthalate species have been calculated at ionic strengths 0.40 and 0.70M, along with the interaction parameters with Na + , from the stability constants found for the species ML and H 2 L, according to the Bronsted-Guggenheim expression. (author)

One step synthesis of 6-oxo-cholestan-3β,5α-diol

Energy Technology Data Exchange (ETDEWEB)

Voisin, Maud; Silvente-Poirot, Sandrine; Poirot, Marc, E-mail: marc.poirot@inserm.fr

2014-04-11

Highlights: • Cholesterol-5,6-epoxides are metabolized into cholestane-3β,5α,6β-triol (CT) in cancer cells. • 6-Oxo-cholestan-3β,5α-diol (OCDO) is a putative metabolite of CT. • The one step syntheses of CT and OCDO from cholesterol are reported. • The one step syntheses of labelled CT and OCDO are reported. - Abstract: Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [{sup 14}C]-cholestane-3β,5α,6β-triol and [{sup 14}C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [{sup 14}C]-cholestane-3β,5α,6β-triol and [{sup 14}C]-6-oxo-cholestan-3β,5α-diol by oxidation of [{sup 14}C]-cholesterol with iodide metaperiodate (HIO{sub 4})

Separation of some metal ions using coupled transport supported liquid membranes

International Nuclear Information System (INIS)

Chaudhary, M.A.

1993-01-01

Liquid membrane extraction processes has become very popular due to their superiority in many ways over other separation techniques. In coupled transport membranes the metal ions can be transported across the membrane against their concentration gradient under the influence of chemical potential difference. Liquid membranes consisting of a carrier-cum-diluent, supported in microporous polymeric hydrophobic films have been studied for transport of metal ions like U(VI), Cr(VI), Be(II), V(V), Ti(IV), Zn(II), Cd(II), Hf(IV), W(VI), and Co(II). The present paper presents basic data with respect to flux and permeabilities of these metal ions across membranes based on experimental results and theoretical equations, using different carriers and diluents and provides a brief reference to possibility of such membranes for large scale applications. (author)

Exploration of the Singlet O2 Oxidation of 8-Oxoguanine by Guided-Ion Beam Scattering and Density Functional Theory: Changes of Reaction Intermediates, Energetics, and Kinetics upon Protonation/Deprotonation and Hydration.

Science.gov (United States)

Sun, Yan; Lu, Wenchao; Liu, Jianbo

2017-02-09

8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) is one of the most common DNA lesions resulting from reactive oxygen species and ionizing radiation, and is involved in mutagenesis, carcinogenesis, and cell death. Notably, 8-oxodGuo is more reactive toward singlet (a 1 Δ g ) O 2 than the undamaged guanosine, and the lesions arising from the secondary oxidation of 8-oxodGuo are more mutagenic. Herein the 1 O 2 oxidation of free base 8-oxoguanine (8-oxoG) was investigated at different initial conditions including protonated [8-oxoG + H] + , deprotonated [8-oxoG - H] - , and their monohydrates. Experiment was carried out on a guided-ion beam scattering tandem mass spectrometer. Measurements include the effects of collision energy (E col ) on reaction cross sections over a center-of-mass E col range from 0.1 to 0.5 eV. The aim of this study is to quantitatively probe the sensitivity of the early stage of 8-oxoG oxidation to ionization and hydration. Density functional theory and Rice-Ramsperger-Kassel-Marcus calculations were performed to identify the intermediates and the products along reaction pathways and locate accessible reaction potential energy surfaces, and to rationalize reaction outcomes from energetic and kinetic points of view. No product was observed for the reaction of [8-oxoG + H] + ·W 0,1 (W = H 2 O) because insurmountable barriers block the addition of 1 O 2 to reactant ions. Neither was [8-oxoG - H] - reactive with 1 O 2 , in this case due to the rapid decay of transient intermediates to starting reactants. However, the nonreactivity of [8-oxoG - H] - was inverted by hydration; as a result, 4,5-dioxetane of [8-oxoG - H] - was captured as the main oxidation product. Reaction cross section for [8-oxoG - H] - ·W + 1 O 2 decreases with increasing E col and becomes negligible above 0.3 eV, indicating that the reaction is exothermic and has no barriers above reactants. The contrasting oxidation behaviors of [8-oxoG + H] + ·W 0,1 and [8-oxoG - H] - ·W 0

31P and 1H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

International Nuclear Information System (INIS)

Jarori, G.K.; Ray, B.D.; Rao, B.D.N.

1989-01-01

The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of 31 P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the δ protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of 31 P relaxation rates in E-MnADP and E-MnATP yields activation energies (ΔE) in the range 6-10 kcal/mol. Thus, the 31 P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and ΔE values in the range 1-2 kcal/mol; i.e., these rates depend upon 31 P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 angstrom, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the 1 H spin-lattice relaxation rate of the δ protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective τ C of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate (τ S1 ) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the δ protons was 10.9 ± 0.3 angstrom

Uptake of metal ions by a silica-based tetraphenylporphyrin sorbent

Energy Technology Data Exchange (ETDEWEB)

Pyrzynska, K.; Sadowska, M.; Trojanowicz, M.

1999-09-01

The [5-p-carboxyphenyl-10,15,20-triphenyl]porphyrin (TPP) covalently attached to aminopropyl silica gel was examined with respect to the sorption of transition metal ions. The distribution coefficients (K{sub d}) are reported for some metal ions with this new sorbent as a function of pH. It was found that in optimum pH conditions the sorption of Cu(II) and Fe(III) is much faster than that of Co(II) and Cr(III). The binding of metal ions is strongly affected by the presence of various species accelerating the complex formation. The application of porphyrin ligands for preconcentration and metal-matrix separation was also examined using complex formation in solution coupled with an anion exchange resin and column chelation procedure, e.g. sorption of metal on an anion exchanger previously loaded with tetra(4-carboxyphenyl)porphyrin.

Bis(1,10-phenanthroline-κ2N,N′(sulfato-κ2O,O′cobalt(II propane-1,3-diol solvate

Directory of Open Access Journals (Sweden)

Kai-Long Zhong

2010-03-01

Full Text Available The title compound, [Co(SO4(C12H8N22]·C3H8O2, was obtained unexpectedly as a by-product during an attempt to synthesize a mixed-ligand complex of CoII with 1,10-phenanthroline (phen and melamine via a solvothermal reaction. The CoII metal ions are in a distorted octahedral coordination environment formed by four N atoms from two chelating phen ligands and two O atoms from a bidentate sulfate ligand. The two chelating N2C2 groups are almost perpendicular to each other [dihedral angle = 80.06 (8°]. A twofold rotation axis passes through the Co and S atoms, and also through the central C atom of the propane-1,3-diol solvent molecule. Intermolecular O—H...O hydrogen bonds help to stabilize the structure.

EPR study of the coordination sphere of Mo5+ ions in UV-irradiated silica-supported molybdenum catalysts

International Nuclear Information System (INIS)

Canose, B.; Gonzalez-Elipe, A.R.; Che, M.

1991-01-01

The determination of the number of coordination vacancies existing at transition metal cations at the surface of bulk or supported oxides is of greater interest in relation to the adsorption and catalytic properties of such systems. In the case of paramagnetic cations, the authors have developed a method consisting of the recording of their first and third derivative EPR spectra after adsorption of 13 CO, ( 13 C, I = 1/2). In this way, the 13 C superhyperfine structure which is normally observed permits the determination of the number of CO molecules bonded to the metal center. In a recent EPR work published in this journal, Seyedmonir and Howe have reported the formation of a CO adduct of the tetrahedral Mo 5+ -OH - species formed by UV-irradiation at 20 K of a MoO 3 /SiO 2 catalyst in the presence of H 2 . In that work, although the structure of such an adduct could not be derived unambiguously on the basis of the g tensor values, the coordination of the Mo 5+ ion by two CO molecules was suggested. This would be in agreement with the previous results with thermally reduced V 2 O 5 /SiO 2 and MoO 3 /SiO 2 catalysts, where the coordination of, respectively, V 4+ and Mo 5+ tetrahedral centers by two CO molecules was proven by means of the combined use of 13 CO and third derivative EPR spectra. In the present work, using this approach, they have studied the structure of these Mo 5+ ions photochemically generated on MoO 3 /SiO 2 catalysts and concluded that only one CO molecule is bonded to the paramagnetic ion

IR, FT-ICR-MS studies on (1'S, 6'S)-1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid hydrochloride salt.

Science.gov (United States)

Lin, Zhiwei

2014-01-01

The infrared spectra of (1'S, 6'S)-1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid hydrochloride salt (CLF-HCl) were studied and compared with free base. Their fragmentation pathways were investigated using tandem mass spectrometric (MS/MS) techniques on Fourier-transform ion cyclotron resonance spectrum, and many characteristic fragment ions were found. Copyright © 2013 Elsevier B.V. All rights reserved.

Preliminary observation on coordination of pellet injection and ion Bernstein wave on a HT-7 tokamak

International Nuclear Information System (INIS)

Yang Yu; Zhao Yanping; Li Jiangang; Wan Baonian; Luo Jiarong; Gu Xuemao

2002-01-01

A pellet injection (PI) experiment was performed during the application of the ion Bernstein wave on a HT-7 tokamak. A preliminary coordination effect was observed. With a lower wave power, shortly after PI, the coupling of the wave was enhanced, and the particle confinement was improved. With higher power, off-axis heating for 15% at about α/3 in the low field side was observed

SPECTROSCOPIC, STRUCTURAL, THERMAL AND ...

African Journals Online (AJOL)

B. S. Chandravanshi

and characterize the complexes of Mn(II), Fe(III), Co(II) and Ni(II) with L in order to ... Studies on 4,6-bis (4-chlorophenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile ..... Mass spectra of (A) L, (B) [Mn(L)2(H2O)2]SO4,(C) [Fe(L)2(H2O)2](NO3)3, (D) .... S.A. Sadeek et al. Bull. Chem. Soc. Ethiop. 2015, 29(1). 86. Thermal analysis.

Two new Co(II)-MOFs based on polymeric chain building units: Crystal structures, and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Han, Min-Le [College of Materials & Chemical Engineering, Collaborative Innovation Center for Microgrid of New Energy of Hubei Province, China Three Gorges University, Yichang 443002 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wu, Ya-Pan; Zhao, Jun [College of Materials & Chemical Engineering, Collaborative Innovation Center for Microgrid of New Energy of Hubei Province, China Three Gorges University, Yichang 443002 (China); Li, Dong-Sheng, E-mail: lidongsheng1@126.com [College of Materials & Chemical Engineering, Collaborative Innovation Center for Microgrid of New Energy of Hubei Province, China Three Gorges University, Yichang 443002 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wang, Yao-Yu [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China)

2015-10-15

Two new Co(II) metal-organic frameworks, namely [Co{sub 2}(bpm)(H{sub 2}O){sub 3}(L)]{sub n} (1) and ([Co(bpe)(H{sub 2}O)(H{sub 2}L)]·(bpe){sub 0.5}·(H{sub 2}O)){sub n} (2), (H{sub 4}L=1,1′:2′,1″-terphenyl-3,3″,4′,5′-tetracarboxylic acid, bpm=bis(4-pyridyl)amine, bpe=1,2-bis(4-pyridyl)ethene), have been obtained under hydrothermal conditions. Both complexes 1 and 2 have been characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complexes 1 and 2 consist of 1D Co(II) chains bridging by carboxylate groups in syn-anti fashion. 1 shows a novel 3D tri-nodal (4,6,10)-connected net with a (3.4{sup 3}.5{sup 2}){sub 2}(3{sup 2}.4{sup 14}.5{sup 12}.6{sup 12}.7{sup 4}.8)(3{sup 2}.4{sup 2}.5{sup 5}.6{sup 4}.7{sup 2}) topology. While 2 exhibits a 2D sql layer. Magnetic susceptibility measurements indicate that both 1 and 2 show weak antiferromagnetic interactions between the adjacent Co(II) ions in 300–8 K for 1 and 300–16 K for 2, respectively, and then 2 also displays ferromagnetic coupling at lower temperatures. - Graphical abstract: Two Co(II) coordination polymers with similar metal chain bridging by carboxylates in syn-anti fashion have been synthesized. Both 1 and 2 show weak antiferromagnetic interactions in high temperature, and then 2 also displays ferromagnetic coupling at lower temperatures. - Highlights: • Two Co(II) coordination polymers with similar metal chain bridging by carboxylates. • A novel 3D (4,6,10)-connected net and a 2D sql layers. • A antiferromagnetic coupling at high temperature for 1 and 2. • A ferromagnetic coupling at lower temperature for 2.

Speciation of Co(II) and Ni(II) in anaerobic bioreactors measured by competitive ligand exchange - adsorptive stripping voltammetry

NARCIS (Netherlands)

Jansen, S.; Steffen, F.; Threels, W.F.; Leeuwen, van H.P.

2005-01-01

Competitive ligand exchange-adsorptive stripping voltammetry is applied to speciation analysis of dissolved Ni(II) and Co(II) in an anaerobic bioreactor and similar batch media. Co and Ni speciation in these media can be measured down to concentration levels of ca. 1 nM. Sulfide interference is

Three coordination compounds based on benzene tetracarboxylate ...

Indian Academy of Sciences (India)

YUNLONG WU

nescence, considerable attention has been focused on the construction of coordination .... measurements were performed on ground powder samples at .... Figure 2. (a) Coordination environment of Co1 ion in compound 2. (b) Coordination.

Crystal structure of poly[[hexaqua-1κ4O,2κ2O-bis(μ3-pyridine-2,4-dicarboxylato-1κO2:2κ2N,O2′;1′κO4cobalt(IIstrontium(II] dihydrate

Directory of Open Access Journals (Sweden)

Zhaojun Yu

2015-09-01

Full Text Available In the title polymeric complex, {[CoSr(C7H3NO42(H2O6]·2H2O}n, the CoII ion, which is situated on a crystallographic centre of inversion, is six-coordinated by two O atoms and two N atoms from two pyridine-2,4-dicarboxylate (pydc2− ligands and two terminal water molecules in a slightly distorted octahedral geometry, to form a trans-[Co(pydc2(H2O2]2− unit. The SrII ion, situated on a C2 axis, is coordinated by four O atoms from four pydc2− ligands and four water molecules. The coordination geometry of the SrII atom can be best described as a distorted dodecahedron. Each SrII ion bridges four [Co(pydc2(H2O2]2− units by four COO− groups of four pydc2− ligands to form a three-dimensional network structure. Two additional solvent water molecules are observed in the crystal structure and are connected to the three-dimensional coordination polymer by O—H...O hydrogen bonds. Further intra- and intermolecular O—H...O hydrogen bonds consolidate the overall structure.

Differential Binding of Co(II) and Zn(II) to Metallo-beta-Lactamase Bla2 from Bacillus anthracis

Energy Technology Data Exchange (ETDEWEB)

Hawk, M.; Breece, R; Hajdin, C; Bender, K; Hu, Z; Costello, A; Bennett, B; Tierney, D; Crowder, M

2009-01-01

In an effort to probe the structure, mechanism, and biochemical properties of metallo-{beta}-lactamase Bla2 from Bacillus anthracis, the enzyme was overexpressed, purified, and characterized. Metal analyses demonstrated that recombinant Bla2 tightly binds 1 equiv of Zn(II). Steady-state kinetic studies showed that mono-Zn(II) Bla2 (1Zn-Bla2) is active, while di-Zn(II) Bla2 (ZnZn-Bla2) was unstable. Catalytically, 1Zn-Bla2 behaves like the related enzymes CcrA and L1. In contrast, di-Co(II) Bla2 (CoCo-Bla2) is substantially more active than the mono-Co(II) analogue. Rapid kinetics and UV-vis, 1H NMR, EPR, and EXAFS spectroscopic studies show that Co(II) binding to Bla2 is distributed, while EXAFS shows that Zn(II) binding is sequential. To our knowledge, this is the first documented example of a Zn enzyme that binds Co(II) and Zn(II) via distinct mechanisms, underscoring the need to demonstrate transferability when extrapolating results on Co(II)-substituted proteins to the native Zn(II)-containing forms.

Spectral, thermal, kinetic, molecular modeling and eukaryotic DNA degradation studies for a new series of albendazole (HABZ) complexes

Science.gov (United States)

El-Metwaly, Nashwa M.; Refat, Moamen S.

2011-01-01

This work represents the elaborated investigation for the ligational behavior of the albendazole ligand through its coordination with, Cu(II), Mn(II), Ni(II), Co(II) and Cr(III) ions. Elemental analysis, molar conductance, magnetic moment, spectral studies (IR, UV-Vis and ESR) and thermogravimetric analysis (TG and DTG) have been used to characterize the isolated complexes. A deliberate comparison for the IR spectra reveals that the ligand coordinated with all mentioned metal ions by the same manner as a neutral bidentate through carbonyl of ester moiety and NH groups. The proposed chelation form for such complexes is expected through out the preparation conditions in a relatively acidic medium. The powder XRD study reflects the amorphous nature for the investigated complexes except Mn(II). The conductivity measurements reflect the non-electrolytic feature for all complexes. In comparing with the constants for the magnetic measurements as well as the electronic spectral data, the octahedral structure was proposed strongly for Cr(III) and Ni(II), the tetrahedral for Co(II) and Mn(II) complexes but the square-pyramidal for the Cu(II) one. The thermogravimetric analysis confirms the presence or absence of water molecules by any type of attachments. Also, the kinetic parameters are estimated from DTG and TG curves. ESR spectrum data for Cu(II) solid complex confirms the square-pyramidal state is the most fitted one for the coordinated structure. The albendazole ligand and its complexes are biologically investigated against two bacteria as well as their effective effect on degradation of calf thymus DNA.

Bituminous solidification, disposal, transport and burial of spent ion-exchange resins. Part of a coordinated programme on treatment of spent ion exchange resins

International Nuclear Information System (INIS)

Mozes, G.; Kristof, M.

1983-07-01

The project dealing with the incorporation of spent ion-exchange resins into bitumen was performed within the Agency coordinated research programme on treatment of spent ion-exchange resins. Physical and chemical properties of commercial ion-exchange resins, bitumens and bituminized resins were studied. It was shown that bitumen with low oil content and with a softening point of 60-70 deg. C are applicable for the incorporation of resins. The final waste form is allowed to contain maximum 50% resin. The comprehensive study of the biological resistance of B-30 bitumen was performed. That showed that any bacteriological attack can be regarded as generally insignificant. A continuously operating technology was realized on a semi-plant scale. The best operating conditions of this technology were determined. On the basis of the experience gained from the experiments a design of the bituminization plant of 50m 3 dry resin/year treatment capacity was proposed

Aloe vera extract reduces 8-oxo-2'-deoxyguanosine levels and improves total antioxidants in streptozotocin-induced diabetic rats

Directory of Open Access Journals (Sweden)

Wulan Christijanti

2017-04-01

Full Text Available Background Diabetes mellitus is a chronic disease caused by lack of insulin production in the pancreas or by insulin resistance, the disease being characterized by elevated blood glucose levels. Hyperglycemia in diabetes could lead to oxidative stress due to the rise in 8-oxo-2'-deoxyguanosine (8-oxo-dG levels and the decrease in levels of total antioxidant status (TAS. The purpose of this study was to assess the effect Aloe vera extract on 8-oxo-dG level and total antioxidant status in diabetic rat testis.   Methods This was an experimental laboratory study with 20 rat samples which were divided into 4 groups (1 control group and 3 treatment groups. Diabetes was induced in the rats by streptozotocin (STZ at 65 mg/kgBW. The diabetic rats were then treated for 28 days with Aloe vera extract at 0 mg (P0, 200 mg rind (P1, 200 mg pulp (P2, respectively. The level of 8 -oxo-dG was measured by ELISA and total antioxidant status with 2,2' -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS. Data were analyzed with ANOVA and Least Significant Difference Advanced Test at P<0.05.   Results 8-Oxo-dG levels were significantly different between the control group and both P0 and P2, but not between the control group and P1. Among the treatment groups the 8-oxo-dG levels were significantly different. Mean total antioxidant status was significantly different between control and treatment groups, and also between treatment groups (p<0.05.   Conclusions Aloe vera extract reduced free radicals (level of 8-oxo-dG and increased the total antioxidant status in diabetic rat testis.

Ligand influences on properties of uranium coordination complexes. Structure, reactivity, and spectroscopy

International Nuclear Information System (INIS)

Kosog, Boris

2012-01-01

In this thesis several different aspects of uranium chemistry are presented. It was shown that terminal uranium(V) oxo and imido complexes [(( R ArO) 3 tacn)U V (O)] and [(( R ArO) 3 tacn)U V (NSiMe 3 )] (R = t Bu, Ad) can be oxidized by silver(I) hexafluoro-antimonate to the uranium(VI) oxo and imido complexes [(( R ArO) 3 tacn)U VI (O)]SbF 6 and [(( R ArO) 3 tacn)U VI (NSiMe 3 )]SbF 6 . While for the t Bu-derivative of the oxo complex an equatorial coordination is observed due to stabilization by the inverse trans-influence, normal axial coordination is observed for the Ad-derivative and both imido complexes. The inverse trans-influence was thus proven to be a key factor for the coordination mode of a terminal ligand on high valent uranium complexes. L III XANES was shown to be a great tool for the determination of oxidation states of uranium complexes. Therefore, a series of uranium complexes in all stable oxidation states for uranium, +III to +VI was prepared, and their spectra analyzed. All compounds bear only O-donor ligands in addition to the chlating trisaryloxide-tacn-ligand. A separation of 1.5 to 3 eV in the white line energy is observed between the different oxidation states. This series can be used as reference for compounds, where oxidation state assignment is not obvious, such as a ketyl radical complex [(( t-Bu Ar)O 3 tacn)U(O-C( t-Bu Ph) 2 .- )]. For this complex, the oxidation state of +IV could be assigned. Moreover, a series of isostructural uranium(IV) complexes was prepared. The influence of different ligands according to the spectrochemical series on the electronic and magnetic properties could be shown using UV/vis/NIR spectroscopy and variable temperature SQUID measurements. Calculations of uranium L III XANES spectra show a variation in the shape of the spectra and thus high resolution PFY-XANES would be a great tool to determine the electronic influence of these different axial ligands. Using the single N-anchored ligand system, the first

Red-excitation resonance Raman analysis of the nu(Fe=O) mode of ferryl-oxo hemoproteins.

Science.gov (United States)

Ikemura, Kenichiro; Mukai, Masahiro; Shimada, Hideo; Tsukihara, Tomitake; Yamaguchi, Satoru; Shinzawa-Itoh, Kyoko; Yoshikawa, Shinya; Ogura, Takashi

2008-11-05

The Raman excitation profile of the nuFe O mode of horseradish peroxidase compound II exhibits a maximum at 580 nm. This maximum is located within an absorption band with a shoulder assignable to an oxygen-to-iron charge transfer band on the longer wavelength side of the alpha-band. Resonance Raman bands of the nuFe O mode of various ferryl-oxo type hemoproteins measured at 590 nm excitation indicate that many hemoproteins in the ferryl-oxo state have an oxygen-to-iron charge transfer band in the visible region. Since this red-excited resonance Raman technique causes much less photochemical damage in the proteins relative to blue-excited resonance Raman spectroscopy, it produces a higher signal-to-noise ratio and thus represents a powerful tool for investigations of ferryl-oxo intermediates of hemoproteins.

Metabolism of leukotriene B4 to dihydro and dihydro-oxo products by porcine leukocytes

International Nuclear Information System (INIS)

Powell, W.S.; Gravelle, F.

1989-01-01

Porcine leukocytes contain a novel pathway for the metabolism of leukotriene B4 (LTB4) which results in reduction of the conjugated triene chromophore to a conjugated diene. These cells converted LTB4 to two major metabolites, both of which exhibited maximal absorbance at 230 nm in their UV spectra. These products were purified by high pressure liquid chromatography and identified as 10, 11-dihydro-LTB4 and 10,11-dihydro-12-oxo-LTB4 on the basis of the mass spectra of various derivatives. The position of the double bond of LTB4 which had been reduced was established by cleaving the remaining double bonds of 10, 11-dihydro-LTB4 with ozone followed by oxidation or reduction of the resulting ozonide and analysis of the products by mass spectrometry. Experiments with deuterium-labeled substrate indicated that LTB4 could be directly converted to 10, 11-dihydro-LTB4 without the prior oxidation of either of its hydroxyl groups, as is required for the formation of dihydro metabolites of prostaglandins. Incubation of porcine leukocytes with 10, 11-dihydro-LTB4 and 10, 11-dihydro-12-oxo-LTB4 indicated that these two products can be interconverted and are in equilibrium with one another. The dihydro-oxo metabolite can therefore be formed from 10, 11-dihydro-LTB4, although we have not ruled out the possibility that it is also produced via 12-oxo-LTB4, which could be a transitory intermediate. These results indicate that porcine leukocytes contain a novel reductase/dehydrogenase pathway distinct from the pathway responsible for the metabolism of prostaglandins. This pathway is also different from the pathway in human polymorphonuclear leukocytes which converts 6-trans-isomers of LTB4 to dihydro products, since the latter pathway involves 5-oxo intermediates and results in a shift in the positions of the remaining double bonds

Investigation of cobalt porphyrin doped polymer membrane films for the optical sensing of imidazole and its derivatives

Directory of Open Access Journals (Sweden)

Yueyang Tan

2015-03-01

Full Text Available A cobalt(II porphyrin was successfully incorporated into polymer membranes for the optical sensing of imidazole and its derivatives. This research has led to a better understanding of the behavior of Co(II porphyrin in solution and in polymeric membranes. In aprotic dichloromethane (DCM, the Co(II tetraphenylporphyrin (CoTPP and Co(II octaethylporphyrin (CoOEP show a sensitive response to imidazole due to the strong ligation of the N-3 on the imidazole ring to the Co(II center, which induces an absorbance change to the Soret band. However, when doped in polymeric films, only the CoTPP exhibits moderate sensitivity towards aqueous imidazole, histamine and histidine. This weakened coordination ability of CoTPP towards imidazole in the polymer films may be due to the coordination of the plasticizer, the impurities from the THF and polymer matrix at the Co(II center. The selectivity of the polymer films towards imidazole over common anions is high. Lifetime of the cobalt(II porphyrin incorporated polymer film was relatively short.

Measurement of 12(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid and its metabolite 12-oxo-5Z,8E,10E-heptadecatrienoic acid in human plasma by gas chromatography/negative ion chemical ionization mass spectrometry

International Nuclear Information System (INIS)

Hofmann, U.; Seefried, S.; Meese, C.O.; Mettang, T.; Huebel, E.K.; Kuhlmann, U.

1990-01-01

Thromboxane A2, the predominant product of arachidonic acid metabolism in the blood platelet, is a potent vasoconstrictor and platelet agonist. During its biosynthesis from cyclic endoperoxide, 12(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) is formed in equal amounts. The further metabolism of HHT, catalyzed by 15-hydroxyprostaglandin dehydrogenase, leads to 12-oxo-5Z,8E,10E-heptadecatrienoic acid (Oxo-HT). Sample workup procedures are described which allow for the sensitive and reproducible determination of these two arachidonic acid metabolites in human plasma by gas chromatography-mass spectrometry in the presence of deuterated analogues as internal standards. HHT is derivatized to the pentafluorobenzyl ester tert-butyldimethylsilyl ether. In order to enable quantification of low concentrations of about 10 pg/ml in nonstimulated human plasma, the samples have to be purified by HPLC. Oxo-HT is derivatized to the pentafluorobenzyl ester, which is purified by HPLC, and then derivatized to the trimethylsilyloxime. The method allows quantification of Oxo-HT in concentrations down to 10 pg/ml plasma. The reported methods have been used to measure HHT and Oxo-HT in stimulated platelet rich plasma and to quantify HHT in nonstimulated plasma. Determination of endogenous levels of these two arachidonic acid metabolites may give new insights into the overall biosynthesis of thromboxane A2 in man

Enhanced sorption of radiocobalt from water by Bi(III) modified montmorillonite: A novel adsorbent

International Nuclear Information System (INIS)

Guo Zhiqiang; Li Yuan; Zhang Shouwei; Niu Haihong; Chen Zhesheng; Xu Jinzhang

2011-01-01

Highlights: → Bi-Mt has higher surface area than Ca-Mt. → The sorption of Co(II) on Bi-Mt is dependent on ionic strength and pH. → The sorption of Co(II) on Bi-Mt is an spontaneous and endothermic process. → Bi-Mt has good practical application potential in wastewater disposal. - Abstract: In this study, Ca-montmorillonite (Ca-Mt) modified with Bi 3+ was used as a novel adsorbent for the sorption of Co(II) from aqueous solutions. The sorption of Co(II) on Bi-montmorillonite (Bi-Mt) was investigated as a function of contact time, pH, ionic strength, adsorbent content, Co(II) concentrations, fulvic acid (FA) and temperature. Compared to Ca-Mt, Bi-Mt showed a higher affinity to bind Co(II) ions. The sorption percentage of Co(II) on Bi-Mt increased with increasing pH at pH 3.0-8.5, and then maintained the high level at pH 8.5-12. The sorption of Co(II) on Bi-Mt was dependent on ionic strength at low pH, and independent of ionic strength at high pH. The presence of FA enhanced Co(II) sorption at low pH, but suppressed Co(II) sorption at high pH. The thermodynamic data derived from temperature dependent sorption isotherms suggested that the sorption of Co(II) on Bi-Mt was spontaneous and endothermic process. Outer-sphere surface complexation and/or ion exchange were the main mechanisms of Co(II) sorption on Bi-Mt at low pH, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. From the experimental results, it is possible to conclude that Bi-Mt is suitable for application of Co(II) removal from aqueous solutions.

coordination polymers derived from two different bis-pyridyl-bis-am

Indian Academy of Sciences (India)

Abstract. Three new Ni(II) coordination polymers exhibiting different 1D and 2D framework structures ... separation, magnetism, ion exchange and so on.5 8 ... of the coordination geometries of metal ions, which ... Cu(II)/Co(II)/Cd(II) coordination polymers containing ..... tion, the concentration of MB and RhB (C) versus reac-.

Coordinated research projects (CRP). Coordinated research project (CRP)

International Nuclear Information System (INIS)

Takagi, Hidekazu; Koike, Fumihiro; Nakamura, Nobuyuki

2013-01-01

In the present paper, the contribution of Japanese scientists in coordinated research projects on thermonuclear fusion. Representative subjects taken in seven projects are the precise computation of theoretical data on electron-molecule collisions in the peripheral plasma, the computation of spectroscopic data of multi-charged tungsten ions, the spectroscopic measurement of multi-charged tungsten ions using an ion trap device, the development of collisional-radiative model for plasmas including hydrogen and helium, the computational and theoretical studies on the behavior of tungsten and beryllium in the plasma-wall interaction, the study on the property of dusts generated in fusion devices. These subjects are those of most important issues in ITER. (author)

Inhibition of mild steel corrosion by 1,4,6-trimethyl-2-oxo-1,2-dihydropyridine-3-carbonitrile and synergistic effect of halide ion in 0.5 M H{sub 2}SO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Mourya, Punita, E-mail: mouryapunita025@gmail.com [Department of Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Singh, Praveen [Department of Chemistry, Banaras Hindu University, Varanasi 221005 (India); Rastogi, R.B.; Singh, M.M. [Department of Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2016-09-01

Highlights: • TODPCN is a good corrosion inhibitor for mild steel in 0.5 M H{sub 2}SO{sub 4} solution. • Addition of iodide ion increases the inhibition efficiency of the studied nitrile derivative. • Inhibition efficiency successively increases with concentration. • XPS study has revealed the chemical composition of the protective film. - Abstract: The effect of iodide ions on inhibitive performance of 1,4,6-trimethyl-2-oxo-1,2-dihydropyridine-3-carbonitrile (TODPCN) on mild steel (MS) corrosion in 0.5 M H{sub 2}SO{sub 4} was studied using gravimetric and electrochemical measurements. TODPCN inhibits the corrosion of MS to the extent of 62.3% at its lowest concentration (0.5 mM) and its inhibition efficiency (η) further increases on increasing concentration at 298 K. The adsorption of TODPCN on MS was found to follow the Langmuir adsorption isotherm. The value of η increased on the addition of 2.0 mM KI. The value of synergism parameter being more than unity indicates that the enhanced η value in the presence of iodide ions is only due to synergism. Thus, a cooperative mechanism of inhibition exists between the iodide anion and TODPCN cations. The increase in surface coverage in the presence of KI indicates that iodide ions enhance the adsorption of TODPCN. The surface morphology of corroded/inhibited MS was studied by atomic force microscopy. X-ray photoelectron spectroscopy of inhibited MS surface was carried out to determine the composition of the adsorbed film. Some quantum chemical parameters and the Mulliken charge densities for TODPCN calculated by density functional theory provided further insight into the mechanism of inhibition.

New functionalized β-diketiminate ligands and f elements

International Nuclear Information System (INIS)

Dulong, Florian

2013-01-01

β-diketiminate ligands have received increased interest in coordination chemistry, especially for homogeneous catalysis. Their successful applications arise from an easy and fine tuning of the ligand electronic and geometric properties. However, these modifications are limited to the introduction of neutral donors (ethers or amines), on the nitrogen substituents of the β-diketiminate skeleton. The main focus of this research project is to overcome this limitation by synthesizing new β-diketiminate ligands functionalized by one or two anionic aryl-oxide groups, and to study their coordination chemistry with lanthanide and actinide ions. Access to these species relies on a fine understanding of the mechanism underlying their formation, and the sensitivity of the β-di-iminium skeleton towards nucleophiles (phenols) has been identified as the limiting side reaction in the synthetic route. Addition of reactants in well defined order allowed the formation of two new N-aryl-oxy-β-diketiminate dianions on a multi-gram scale. The two ligands differ by their steric bulk and exhibit different coordination behaviors towards lanthanides and actinide ions, which were rationalized on geometric considerations. The reactivity of three of these new complexes has been investigated. A Ce(III) N-aryl-oxy-β-diketiminate complex exhibits interesting reduction properties, due to the shift of its oxidation potential to negative values by its coordination environment. A Th(IV) complex presents a vacant coordination site, which has been probed with different Lewis bases, emphasizing two spatial arrangements ruled by inter-ligand repulsion. It has been compared to its U(IV) analogue, which can be oxidized to a rare terminal mono-oxo uranium(VI) species. The latter was reversibly reduced to its U(V) and U(IV) derivatives, creating the first series of terminal mono-oxo uranium complexes with three successive oxidation states. These compounds represent an opportunity to better understand

3-oxo-rhazinilam: a new indole alkaloid from Rauvolfia serpentina x Rhazya stricta hybrid plant cell cultures.

Science.gov (United States)

Gerasimenko, I; Sheludko, Y; Stöckigt, J

2001-01-01

A new monoterpenoid indole alkaloid, 3-oxo-rhazinilam (1), was isolated from intergeneric somatic hybrid cell cultures of Rauvolfia serpentina and Rhazya stricta, and the structure was determined by detailed 1D and 2D NMR analysis. It was also proved that 3-oxo-rhazinilam (1) is a natural constituent of the hybrid cells.

Reactions of 1-methyl-derivatives of 2-oxo-1,2,3,4-tetrahydropyrimidine with phosphorus pentachloride and phosphorus oxychloride

International Nuclear Information System (INIS)

Khanina, E.L.; Liepin'sh, E.E.; Mutsenietse, D.Kh.; Dubur, G.Ya.

1987-01-01

In the reaction of 4-phenyl-and 4,6-diphenyl-1-methyl-2-oxo-5-ethoxycarbonyl-1,2,3,4-tetrahydropyrimidines with phosphorus pentachloride, oxidation and dealkylation takes place in addition to chlorination and as a result one obtained 4-phenyl- and 4,6-diphenyl-1-methyl-5-ethoxycarbonyl-2-pyrimidones and also 4-phenyl-, (4,6-diphenyl)-5-ethoxycarbonyl-2-chloropyrimidines. 1,6-Dimethyl-2-oxo-4-phenyl-5-ethoxycarbonyl-1,2,3,4-tetrahydropyrimidine in the same reaction gives 1-methyl-2-oxo-4-phenyl-5-ethoxycarbonyl 6-dichloromethyl-1,2,3,4-tetrahydropyrimidine, together with 6-chloromethylene- and 6-dichloromethylene-1-methyl-2-oxo-4-phenyl-5-chloro-5-ethoxycarbonylhexahydropyrimidines. The structure was established on the basis of elemental analysis, proton NMR spectra, and carbon-13 NMR spectra, taking into account the long-range 2 H- 13 C coupling constants

Nucleation-growth of salicylic acid-oxoTiO{sub 2} colloids synthesized by sol-gel processing

Energy Technology Data Exchange (ETDEWEB)

Tieng, S.; Jia, Z. [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse (France); Subra-Paternault, P. [Laboratoire de Chimie et Biologie des Membranes et Nanoobjets, CBMN – UMR 5248, Bâtiment, 14B, Allée Geoffroy Saint Hilaire, 33600 Pessac (France); Kanaev, A. [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse (France); Chhor, K., E-mail: khay.chhor@lspm.cnrs.fr [Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, 93430 Villetaneuse (France)

2014-12-15

In this work, the preparation of hybrid oxo-TiO{sub 2} nanoparticles modified by salicylic acid (SA) is reported. The size-selected TiO{sub 2} nanoparticles were synthesized in a sol-gel reactor with rapid micromixing of reagents and binding of SA molecules occurs at the nucleation stage. UV-visible absorption, Raman spectroscopy and Light scattering measurements evidence the formation of a SA–oxo-TiO{sub 2} charge-transfer complex. In particularly, the C=O vibration mode of SA shifts to lower frequencies upon complexation while the C-O vibration modes of both carboxylate and phenolic groups retain their position. The absence of C-O shift comes from two effects that cancel each other, i.e. the hardening of this mode related to the C=O mode changes and its softening due to the replacement of hydrogen in COH group by Ti atoms. Kinetic studies of the oxo-TiO{sub 2} nanoparticles nucleation and growth in presence of SA show that the acidic ligand at the nanoparticle surface acts as an attractor for another oxo-TiO{sub 2} nanoparticle leading to polycondensation. This mechanism is responsible for the acceleration of the nanoparticle aggregation kinetics and shortening of the induction time. The hybrid nanoparticles are stable at pH ≤ 7.7 and release SA molecules at pH ≥ 8.5. - Highlights: • Hybrid oxo-TiO{sub 2} nanoparticles modified by salicylic acid (SA) are prepared. • The synthesis is achieved during the nucleation stage of sol-gel process. • The formation of SA–oxo-TiO{sub 2} charge-transfer complex is evidenced. • Mechanism responsible for the acceleration of the nanoparticle aggregation kinetics is proposed. • SA-TiO{sub 2} nanoparticles are stable at pH ≤ 7.7 and release SA molecules at pH ≥ 8.5.

Summary report of second research coordination meeting on development of a reference database for ion beam analysis

International Nuclear Information System (INIS)

Vickridge, Ian; Schwerer, Otto

2007-07-01

Highlights of the 2nd Research Coordination Meeting (RCM) are given with respect to the progress achieved in the first 1 1/2 years of the Co-ordinated Research Project (CRP) on Development of a Reference Database for Ion Beam Analysis. Participants presented the results of their work to date, and identified and assigned key tasks required to ensure that the final output of the CRP is achieved. In addition, a number of lively and productive discussions took place concerning technical issues such as accelerator energy calibration, error reporting, accuracy of the existing IBANDL and EXFOR datasets for IBA, and procedures for producing recommended cross-section data. The main conclusions as well as lists of actions and tasks are presented in this report. (author)

Layered double hydroxide-enhanced luminescence in a Fenton-like system for selective sensing of cobalt in Hela cells

Science.gov (United States)

Yu, Mei; Yuan, Zhiqin; Lu, Chao

2017-09-01

This work presented a facile and eco-friendly method for the determination of cobalt ions (Co(II)) in living cells based on layered double hydroxides (Mg-Al CO3-LDHs) enhanced chemiluminescence (CL) emission of a Co(II)-hydrogen peroxide-sodium hydroxide system. The enhanced CL emission was attributed to the large specific surface area of Mg-Al CO3-LDHs, which facilitates the generation of an excited-stated intermediate. The proposed method displayed high selectivity toward Co(II) over other metal ions. Under the optimal conditions, the increased CL intensity showed a linear response versus Co(II) concentration in the range of 5.0-1000 nM with a detection limit of 3.7 nM (S/N = 3). The relative standard deviation for nine repeated measurements of 100 nM Co(II) was 3.2%. Furthermore, the proposed method was successfully applied to detect Co(II) in living cell samples, and the results were agreed with those obtained by the standard ICP-MS method.

Solution structures of lipoyl domains of the 2-oxo acid dehydrogenase complexes from Azotobacter vinelandii : implications for molecular recognition

NARCIS (Netherlands)

Berg, A.

1997-01-01

The 2-oxo acid dehydrogenase complexes are large multienzyme complexes that catalyse the irreversible oxidative decarboxylation of a specific 2-oxo acid to the corresponding acyl-CoA derivative. The pyruvate dehydrogenase complex (PDHC) converts the product of the glycolysis, pyruvate, to

Preparation and studies of Co(II) and Co(III)-substituted barium ferrite prepared by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Teh, Geok Bee [Department of Bioscience and Chemistry, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Kuala Lumpur (Malaysia)]. E-mail: tehgb@mail.utar.edu.my; Nagalingam, Saravanan [Department of Bioscience and Chemistry, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Kuala Lumpur (Malaysia); Jefferson, David A. [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

2007-01-15

The sol-gel preparative method was employed to synthesise Co(II) and Co(III)-substituted barium ferrite. This method was attempted to achieve higher homogeneity of the final product. Samples of substituted ferrites were characterised by various experimental techniques including high resolution transmission electron microscopy, X-ray diffraction analysis, magnetometry and thermal gravimetric analysis. The microstructural changes induced by such substitution are also discussed.

Preparation and studies of Co(II) and Co(III)-substituted barium ferrite prepared by sol-gel method

International Nuclear Information System (INIS)

Teh, Geok Bee; Nagalingam, Saravanan; Jefferson, David A.

2007-01-01

The sol-gel preparative method was employed to synthesise Co(II) and Co(III)-substituted barium ferrite. This method was attempted to achieve higher homogeneity of the final product. Samples of substituted ferrites were characterised by various experimental techniques including high resolution transmission electron microscopy, X-ray diffraction analysis, magnetometry and thermal gravimetric analysis. The microstructural changes induced by such substitution are also discussed

The study on the ion exchange behavior of metal ions using composite ion exchange resin

Energy Technology Data Exchange (ETDEWEB)

Kim, Kukki; Lee, Kunjai [Nuclear Engineering Department Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Kim, Youngkyun [Korea Institute of Nuclear Safety, Daejon (Korea, Republic of); Lee, Sangjin; Yang, Hoyeon; Ha, Jonghyun [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

2002-04-15

In this study, a series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. And a separation of metal ions in the liquid radioactive waste have been performed using organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite. The PSF-F (phenol sulphonic formaldehyde-iron ferrite) composite resin prepared by the above method shows stably high removal efficiency to Co(II), Fe, Cs species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i. e. pH 4.0 to 10.3) implies that the PSF-F composite resin overcomes the limitations of the conventional ferrite process which is practically applicable only to alkaline conditions. The experiment proceeded using batch reactor in a constant temperature with water bath. The experiments divided into three parts. The first one is TG/DTA (Thermogravimetry / Differential Thermal Analysis) which can analyze the trend of pyrolysis of PSF-F ion exchanger. The Second one is equilibrium experiment in which the separation factor of metal ions and Langmuir, Freundlich isotherm was achieved. The last one is kinetics experiment in which the equilibrium reaction time and removal efficiency is estimated.

The study on the ion exchange behavior of metal ions using composite ion exchange resin

International Nuclear Information System (INIS)

Kim, Kukki; Lee, Kunjai; Kim, Youngkyun; Lee, Sangjin; Yang, Hoyeon; Ha, Jonghyun

2002-01-01

In this study, a series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. And a separation of metal ions in the liquid radioactive waste have been performed using organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite. The PSF-F (phenol sulphonic formaldehyde-iron ferrite) composite resin prepared by the above method shows stably high removal efficiency to Co(II), Fe, Cs species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i. e. pH 4.0 to 10.3) implies that the PSF-F composite resin overcomes the limitations of the conventional ferrite process which is practically applicable only to alkaline conditions. The experiment proceeded using batch reactor in a constant temperature with water bath. The experiments divided into three parts. The first one is TG/DTA (Thermogravimetry / Differential Thermal Analysis) which can analyze the trend of pyrolysis of PSF-F ion exchanger. The Second one is equilibrium experiment in which the separation factor of metal ions and Langmuir, Freundlich isotherm was achieved. The last one is kinetics experiment in which the equilibrium reaction time and removal efficiency is estimated

Organo-gallium and indium complexes with dithiolate and oxo ligands

Indian Academy of Sciences (India)

Page 1 ... of several of these com- plexes have been established by single crystal X-ray diffraction analyses. Complexes derived from oxo ligands ... diode) applications.8. Organometallic complexes derived from chelating ligands, such as substituted. 8-hydroxyqunoline and azomethine linkages, are emerging as potential ...

Formation process of the poly-oxo cluster U{sub 38}

Energy Technology Data Exchange (ETDEWEB)

Henning, Christoph [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Molecular Structures; Falaise, C.; Volkringer, Christoph; Loiseau, T. [Lille Univ., Villeneuve d' Ascq (France). Unite de Catalyse et Chimie du Solide

2016-07-01

Recently, a new poly-oxo cluster with 38 uranium atoms, U{sub 38}O{sub 56}Cl{sub 18}(THF){sub 8}(bz){sub 24}.8THF, (U{sub 38}), has been synthesized [1]. We studied ex situ the reaction kinetics of this complex [2].

Mechanistic insights into dioxygen activation, oxygen atom exchange and substrate epoxidation by AsqJ dioxygenase from quantum mechanical/molecular mechanical calculations.

Science.gov (United States)

Song, Xudan; Lu, Jiarui; Lai, Wenzhen

2017-08-02

Herein, we use in-protein quantum mechanical/molecular mechanical (QM/MM) calculations to elucidate the mechanism of dioxygen activation, oxygen atom exchange and substrate epoxidation processes by AsqJ, an Fe II /α-ketoglutarate-dependent dioxygenase (α-KGD) using a 2-His-1-Asp facial triad. Our results demonstrated that the whole reaction proceeds through a quintet surface. The dioxygen activation by AsqJ leads to a quintet penta-coordinated Fe IV -oxo species, which has a square pyramidal geometry with the oxo group trans to His134. This penta-coordinated Fe IV -oxo species is not the reactive one in the substrate epoxidation reaction since its oxo group is pointing away from the target C[double bond, length as m-dash]C bond. Instead, it can undergo the oxo group isomerization followed by water binding or the water binding followed by oxygen atom exchange to form the reactive hexa-coordinated Fe IV -oxo species with the oxo group trans to His211. The calculated parameters of Mössbauer spectra for this hexa-coordinated Fe IV -oxo intermediate are in excellent agreement with the experimental values, suggesting that it is most likely the experimentally trapped species. The calculated energetics indicated that the rate-limiting step is the substrate C[double bond, length as m-dash]C bond activation. This work improves our understanding of the dioxygen activation by α-KGD and provides important structural information about the reactive Fe IV -oxo species.

Synthesis and characterization of transition metal complexes derived from some biologically active furoic acid hydrazones

Directory of Open Access Journals (Sweden)

P. Venkateswar Rao

2007-04-01

Full Text Available Two new physiologically active ligands, N’-2-[(E-1-hydroxy-4-methyl-2-oxo-2H-8-chromenyl ethylidene-2-furan carbohydrazide (HMCFCH and N’-2-[(Z-1-(4-hydroxy-6-methyl-2-oxo-2H-pyranyl ethylidene]-furan carbohydrazide (HMPFCH and their VO(II, Mn(II, Fe(II, Co(II, Ni(II and Cu(II complexes have been prepared. The ligands and the metal complexes have been characterized by elemental analyses, electrical conductance, magnetic susceptibility measurements, UV-Vis, IR, and ESR spectroscopic data. Basing on the above data, Fe(II and Co(II complexes of HMCFCH and HMPFCH have been assigned a dimeric octahedral geometry. VO(II complexes of HMCFCH and HMPFCH have been assigned sulfate bridged dimeric square pyramidal geometry. Mn(II complex of HMCFCH has been assigned a dimeric octahedral geometry, where as Mn(II complex of HMPFCH has been ascribed to monomeric octahedral geometry. Cu(II and Ni(II complexes of HMCFCH have been ascribed to a polymeric structure. Ni(II complex of HMPFCH has been assigned a dimeric square planar geometry. Cu(II complex of HMPFCH has been proposed an octahedral geometry. The ligands and their metal chelates were screened against S. aureus and P. aeruginosa. The ligands and the metal complexes have been found to be active against these microorganisms. The ligands show more activity than the metal complexes.

Cobalt(III)-oxo cubane clusters as catalysts for oxidation of organic ...

Indian Academy of Sciences (India)

been prepared by a general method and these have been characterized by analytical, spectroscopic, electro- chemical and ... alkylaromatics, alkenes and alcohols.1 Several indus- .... us to obtain the cobalt(III)-oxo clusters in good to very.

Oxo Crater on (1) Ceres: Geological History and the Role of Water-ice

Energy Technology Data Exchange (ETDEWEB)

Nathues, A.; Platz, T.; Hoffmann, M.; Thangjam, G.; Le Corre, L.; Reddy, V. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Goettingen (Germany); Cloutis, E. A.; Applin, D. M. [University of Winnipeg, Winnipeg, MB R3B 2E9 (Canada); Mengel, K. [IELF, TU Clausthal, Adolph-Roemer-Straße 2A, D-38678 Clausthal-Zellerfeld (Germany); Protopapa, S. [University of Maryland, Department of Astronomy, College Park, MD 20742 (United States); Takir, D. [SETI Institute, Mountain View, CA 94043 (United States); Preusker, F. [German Aerospace Center (DLR), Institute of Planetary Research, D-12489 Berlin (Germany); Schmidt, B. E. [Georgia Institute of Technology, Atlanta, GA (United States); Russell, C. T., E-mail: nathues@mps.mpg.de [Institute of Geophysics and Planetary Physics, Dept. of Earth, Planetary and Space Sciences, University of California Los Angeles, Los Angeles, CA (United States)

2017-09-01

Dwarf planet Ceres (∅ ∼ 940 km) is the largest object in the main asteroid belt. Investigations suggest that Ceres is a thermally evolved, volatile-rich body with potential geological activity, a body that was never completely molten, but one that possibly partially differentiated into a rocky core and an ice-rich mantle, and may contain remnant internal liquid water. Thermal alteration and the infall of exogenic material contribute to producing a (dark) carbonaceous chondritic-like surface containing ammoniated phyllosilicates. Here we report imaging and spectroscopic analyses of data on the bright Oxo crater derived from the Framing Camera and the Visible and Infrared Spectrometer on board the Dawn spacecraft. We confirm that the transitional complex crater Oxo (∅ ∼ 9 km) exhibits exposed surface water-ice. We show that this water-ice-rich material is associated exclusively with two lobate deposits at pole-facing scarps, deposits that also contain carbonates and admixed phyllosilicates. Due to Oxo’s location at −4802 m below the cerean reference ellipsoid and its very young age of only 190 ka (1 σ : +100 ka, −70 ka), Oxo is predestined for ongoing water-ice sublimation.

Physical and chemical transformations of μ-oxo dimers and alkoxy complexes of Fe-octaethylporphyrins in solids and in solutions

Science.gov (United States)

Ivashin, N. V.; Shulga, A. M.; Terekhov, S. N.; Dzilinski, K.

1996-11-01

It has been found that relatively small changes in conditions of crystallization in the synthesis process of μ-oxo dimers can lead to quite different products with dimeric or monomeric structures. Molecular structures of these products, discussed on the basis of Fe-octaethylporphyrin (FeOEP) complexes, have been studied using IR, NMR, EPR, resonance Raman (RR), mass and Mössbauer spectroscopies. The use of chloroform with admixture of alcohols (methanol, deuteromethanol and ethanol) in place of pure chloroform for crystallization of the eluate obtained during synthesis of μ-oxo dimers leads to the formation of alkoxy complexes instead of the μ-oxo dimers. It has been also established that dissolution of the μ-oxo dimers in chloroform-ethanol or chloroform-methanol mixtures leads to conversion of the μ-oxo dimers into the alkoxy complexes after evaporation of the solvents. Methoxy and ethoxy ligands in Fe(OEP)OCH 3 and Fe(OEP)OC 2H 5 complexes can exchange the positions during addition of ethanol to the former and methanol to the latter complex in solution. The possibility of generation of doubly bridged structures of the type: OEP Fe< RRFe OEP where R is OCH 3 or OC 2H 5 is discussed.

The activity state of the branched-chain 2-oxo acid dehydrogenase complex in rat tissues.

OpenAIRE

Wagenmakers, A J; Schepens, J T; Veldhuizen, J A; Veerkamp, J H

1984-01-01

An assay is described to define the proportion of the branched-chain 2-oxo acid dehydrogenase complex that is present in the active state in rat tissues. Activities are measured in homogenates in two ways: actual activities, present in tissues, by blocking both the kinase and phosphatase of the enzyme complex during homogenization, preincubation, and incubation with 1-14C-labelled branched-chain 2-oxo acid, and total activities by blocking only the kinase during the 5 min preincubation (neces...

Crystal structure of bis{μ2-2,2′-[(4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diylbis(methylene]bis(4-oxo-4H-pyran-3-olato}dicobaltcalcium bis(perchlorate 1.36-hydrate

Directory of Open Access Journals (Sweden)

Patrizia Rossi

2017-12-01

Full Text Available The title compound, [CaCo2(C22H30N4O62](ClO42·1.36H2O or {Ca[Co(H–2L1]2}·2ClO4·1.36H2O {where L1 is 4,10-bis[(3-hydroxy-4-pyron-2-ylmethyl]-1,7-dimethyl-1,4,7,10-tetraazacyclododecane}, is a trinuclear complex whose asymmetric unit comprises a quarter of the {Ca[Co(H–2L1]2}2+ trinuclear complex, half of a perchlorate ion and 0.34-water molecules. In the neutral [Co(H–2L1] moiety, the cobalt ion is hexacoordinated in a trigonal–prismatic fashion by the surrounding N4O2 donor set. A Ca2+ cation holds together two neutral [Co(H–2L1] moieties and is octacoordinated in a distorted trigonal–dodecahedral fashion by the surrounding O atoms belonging to the deprotonated oxide and carbonyl groups of two [Co(H–2L1] units. The coordination of the CoII cation preorganizes L1 and an electron-rich area forms, which is able to host hard metal ions. The comparison between the present structure and the previously published ones suggests a high versatility of this ligand; indeed, hard metal ions with different nature and dimensions lead to complexes having different stoichiometry (mono- and dinuclear monomers and trinuclear dimers or even a polymeric structure. The heterotrinuclear CoII–CaII–CoII complexes are connected in three dimensions via weak C—H...O hydrogen bonds, which are also responsible for the interactions with the perchlorate anions and the lattice water molecules. The perchlorate anion is disordered about a twofold rotation axis and was refined giving the two positions a fixed occupancy factor of 0.5. The crystal studied was refined as a two-component inversion twin [BASF parameter = 0.14 (4].

Multinuclear NMR characterization of CTAB-hexanol-water, sodium oleate-butanol-water and triton X-100-decanol-water microemulsions

International Nuclear Information System (INIS)

Nagy, J.B.; Bodart-Ravet, I.; Derouane, E.G.; Gourgue, A.; Verfaillie, J.P.

1989-01-01

Multinuclear NMR is a very valuable tool to characterize micellar systems or microemulsions. It allows one to determine c.m.c. values, to study the dissolution of organic molecules, the solvation of cations and anions, the structural changes occurring in a ternary diagram, the mobility of the molecules, etc. This review paper essentially deals with the characterization of cationic (CTAB-hexanol-water), anionic (sodium oleate-butanol-water) and neutral (Triton X-100-decanol-water) reversed micelles. The use of paramagnetic ions [Ni(II), CO(II), Fe(III), etc.] is particularly emphasized to characterize the site of solubilization and their interaction with surfactant and cosurfactant molecules 13 C-NMR). It is concluded, that the metallic ions are basically solvated in the inner water cores and one or more hexanol molecules are included in their first coordination shells in the CTAB-hexanol-water microemulsions. In the Triton X-100-decanol-water microemulsions, both decanol and Triton X-100 molecules enter the first coordination shell of Co(II) ions which are dissolved in both aqeous water cores and the organic medium. 19 F-NMR of a fluorinated probe molecule is particularly useful to study the size of the inner water cores. The method is based on the partition of the molecules between the interface and the organic medium. However, this method has to be applied with great care, and the computed data have to be compared to other physico-chemical results. Both 19 F- and 23 Na-NMR results show a great variation of the behaviour of the sodium oleate-butanol-water system in the so-called bicontinuous region. The Na + ions are oriented independently on a hypothetical inverse micellar droplet. (author). 43 refs.; 18 figs.; 7 tabs

Biosorption of heavy metal ions from aqueous solution by red macroalgae.

Science.gov (United States)

Ibrahim, Wael M

2011-09-15

Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment. Copyright © 2011 Elsevier B.V. All rights reserved.

Theoretical investigation on the mechanism and dynamics of oxo exchange of neptunyl(VI) hydroxide in aqueous solution.

Science.gov (United States)

Yang, Xia; Chai, Zhifang; Wang, Dongqi

2015-03-21

Four types of reaction mechanisms for the oxo ligand exchange of monomeric and dimeric neptunyl(VI) hydroxide in aqueous solution were explored computationally using density functional theory (DFT) and ab initio classical molecular dynamics. The obtained results were compared with previous studies on the oxo exchange of uranyl hydroxide, as well as with experiments. It is found that the stable T-shaped [NpO3(OH)3](3-) intermediate is a key species for oxo exchange in the proton transfer in mononuclear Path I and binuclear Path IV, similar to the case of uranyl(VI) hydroxide. Path I is thought to be the preferred oxo exchange mechanism for neptunyl(VI) hydroxide in our calculations, due to the lower activation energy (22.7 and 13.1 kcal mol(-1) for ΔG(‡) and ΔH(‡), respectively) of the overall reaction. Path II via a cis-neptunyl structure assisted by a water molecule might be a competitive channel against Path I with a mononuclear mechanism, owing to a rapid dynamical process occurring in Path II. In Path IV with the binuclear mechanism, oxo exchange is accomplished via the interaction between [NpO2(OH)4](2-) and T-shaped [NpO3(OH)3](3-) with a low activation energy for the rate-determining step, however, the overall energy required to fulfill the reaction is slightly higher than that in mononuclear Path I, suggesting a possible binuclear process in the higher energy region. The chemical bonding evolution along the reaction pathways was discussed by using topological methodologies of the electron localization function (ELF).

Template synthesis, characterization and antimicrobial activity of the complex combinations of some transitional metals with isonicotinoylhydrazone -2,4,6- trimethylbenzaldehyde

International Nuclear Information System (INIS)

Mitu, L.ITU; Imran, M.

2011-01-01

The complexes of Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) with isonicotinoyl-hydrazone -2,4,6-trimethylbenzaldehyde (INHTB) are reported. The complexes have been characterized by analytical data, IR, UV-Vis, NMR spectra, magnetic susceptibility, thermal analysis and for the Cu(II) complex the ESR spectrum has been recorded. The anti-bacterial activity of these complexes were investigated against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Shigella flexneri bacteria. The INHTB ligand is coordinated at the metallic ions by oxygen amide (O=C) and the azomethine nitrogen. (author)

3. research coordination meeting on development of a reference data base for ion beam analysis. Summary report

International Nuclear Information System (INIS)

Abriola, D.; Vickridge, I.

2009-12-01

Highlights of the third and last Research Coordination Meeting are given with respect to the progress achieved in the Co-ordinated Research Project on Development of a Reference Database for Ion Beam Analysis. The meeting took place at the IAEA headquarters in Vienna from 27 March to 3 April 2009. Participants presented the results of their work and identified and assigned key tasks in pursuance of the final output of the CRP, in particular the update of the IBANDL library and the drafting of the final Technical Report of the CRP. In addition, a number of productive discussions took place concerning issues such as measurements, assessments, evaluations, benchmarks and recommendations. The main conclusions as well as lists of responsibilities and tasks towards the production of the final report are presented. (author)

Reversible formation of high-valent-iron-oxo-porphyrin intermediate in heme-based catalysis: revisiting the kinetic model for horseradish peroxidase.

NARCIS (Netherlands)

Haandel, van M.J.H.; Primus, J.L.; Teunis, C.; Boersma, M.G.; Osman, A.M.; Veeger, C.; Rietjens, I.M.C.M.

1998-01-01

Many heme-containing biocatalysts exert their catalytic action through the initial formation of so-called high-valent-iron-oxo porphyrin intermediates. For horseradish peroxidase the initial intermediate formed has been identified as a high-valent-iron-oxo porphyrin π-radical cation, called compound

The inflation of ion strength in the formation of co-ordination compounds in system of the Fe(III)-Fe(II)-benzimidazole-water in the 298 K

International Nuclear Information System (INIS)

Nazarova, Kh.D.; Rajabov, U.R.; Yusupov, Z.N.

2005-01-01

With the Method of Oxredmatrion with application of the Oxidation Function in the Temperature 298 K and ion strength 0.1; 0.25; 0.50 and 1.00 in the Water solution of Benzimidazole been obtained the Formation Constants of the Coordination and their dependence with ion strength

Co-ordination of heterovalent cation impurities in molten salts

International Nuclear Information System (INIS)

Andreoni, W.; Rovere, M.; Tosi, M.P.

1982-01-01

The local liquid structure around heterovalent cation impurities in molten chlorides is discussed in relation to spectroscopic data on solutions of transition metal ions. A tightly packed, low co-ordination shell is shown to be favoured by Coulomb ionic interactions for physically reasonable values of the size of the impurity. A competition between these forces and ''crystal field'' interactions favouring octahedral co-ordination is thus to be expected for many transition metal ions, as suggested by Gruen and McBeth. The transition observed for some transition metal ions from higher to lower co-ordination with increasing temperature is attributed primarily to entropy differences, that are roughly estimated in a solid-like model. (author)

Synthesis, physico-chemical characterization and biological activity of 2-aminobenzimidazole complexes with different metal ions

Directory of Open Access Journals (Sweden)

Podunavac-Kuzmanović Sanja O.

2004-01-01

Full Text Available Complexes of 2-aminobenzimidazole (L with nitrates of cobalt(II nickel(II, copper (II, zinc(II and silver(I were synthesized. The molar ratio metal:ligand in the reaction of the complex formation was 1:2. It should be noticed, that the reaction of all the metal salts yielded bis(ligand complexes of the general formula M(L2(NO32 × nH2O (M=Co, Ni Cu, Zn or Ag; n=0, 1, 2 or 6. The complexes were characterized by elemental analysis of the metal, molar conductivity, magnetic susceptibility measurements and IR spectra. Co(II, Ni(II and Cu(II complexes behave as non-electrolytes, whilst Zn(II and Ag(I are 1:1 electrolytes. Cu(II complex has a square-planar stereochemistry, Ag(I complex is linear, whilst the Co(II, Ni(II and Zn(II complexes have a tetrahedral configuration. In all the complexes ligand is coordinated by participation of the pyridine nitrogen of the benzimidazole ring. The antimicrobial activity of the ligand and its complexes against Pseudomonas aeruginosa, Bacillus sp. Staphylococcus aureus and Saccharomyces cerevisiae was investigated. The effect of metal on the ligand antimicrobial activity is discussed.

Crystal Structures and Characterizations of Bis(1-benzoyl methyl-benzotriazole-N3)dichoro Metal(II) Complex:[MCl2-(C6H4N3CH2COPh)2] [M＝Zn(II), Co(II)

Institute of Scientific and Technical Information of China (English)

JIAN,Fang-Fang(建方方); SUN,Ping-Ping(孙萍萍); XIAO,Hai-Lian(肖海连); JIAO,Kui(焦奎)

2004-01-01

The structures of [MCl2(C6H4N3CH2COPh)2] [M＝Zn(II) (1), Co(II) (2)] have been determined by X-ray crystallography. They were characterized by elemental analysis, IR spectrum, electronic spectrum and thermogravimetric-differential thermal analysis. They all crystallize in the triclinic system, space group Pī, with lattice parameters a＝0.9449(2) nm, b＝1.1291(2) nm, c＝1.3637(3) nm, α＝111.70(3)°, β＝94.33(3)°, γ＝90.97(3), Z＝2 for compound 1; a＝0.9437(2) nm, b＝1.1277(2) nm, c＝1.3650(3) nm, α＝111.76(3)°, β＝94.50(3)°, γ＝90.80(3)°, Z＝2 for compound 2. The metal ions are all coordinated by two Cl- anions and two nitrogen atoms of 1-benzoylmethyl-benzotriazole ligands, forming the distorted tetrahedral geometry. The Zn-Cl and Zn-N bond lengths are 0.2209(2), 0.2210(2) nm and 0.2059(4), 0.2067(4) nm, respectively. The Co-Cl and Co-N bond lengths are 0.2215(2), 0.2222(2) nm and 0.2028(5), 0.2045(5) nm, respectively. The thermogravimetric (TG) data indicate that they are nearly similar in TG curve, and there are not structural transitions in the two compounds. They all have a high thermal stability. But, there is little difference in DTG (differential thermogravimetric) curves of those two compounds. Elemental analysis, electronic and IR spectra are in agreement with the structural data.

Optical properties of 3d transition metal ion-doped sodium borosilicate glass

International Nuclear Information System (INIS)

Wen, Hongli; Tanner, Peter A.

2015-01-01

Graphical abstract: Photographs of undoped (SiO 2 ) 50 (Na 2 O) 25 (B 2 O 3 ) 25 (SiNaB) glass and transition metal ion-doped (TM) 0.5 (SiO 2 ) 49.5 (Na 2 O) 25 (B 2 O 3 ) 25 glass samples. - Highlights: • 3d transition metal ion (from Ti to Zn) doped SiO 2 -Na 2 O-B 2 O 3 glasses. • Optical properties of doped glasses investigated. • V(IV,V); Cr(III, VI); Mn(II,III); Fe(II,III); Co(II); Ni(II); Cu(II) by XANES, DRS. • Strong visible absorption but only vanadium ion gives strong emission in glass. - Abstract: SiO 2 -Na 2 O-B 2 O 3 glasses doped with 3d-transition metal species from Ti to Zn were prepared by the melting-quenching technique and their optical properties were investigated. The X-ray absorption near edge spectra of V, Cr, and Mn-doped glasses indicate that the oxidation states of V(IV, V), Cr(III, VI) and Mn(II, III) exist in the studied glasses. The oxidation states revealed from the diffuse reflectance spectra of the glasses are V(IV, V), Cr(III, VI), Mn(III), Fe(II, III), Co(II), Ni(II), and Cu(II). Most of the 3d transition element ions exhibit strong absorption in the visible spectral region in the glass. Under ultraviolet excitation, the undoped sodium borosilicate glass produces weak and broad emission, while doping of vanadium introduces strong and broad emission due to the V(V) charge transfer transition. Only weak emission is observed from Ti(IV), Mn(II), Fe(III) and Cu(II), partly resulting from the strong electron–phonon coupling of the 3d-electrons and the relatively high phonon energy of the studied glass host, with the former leading to dominant nonradiative relaxation based on multiphonon processes for most of the 3d excited states

Removal of Cobalt Ion by Adsorbing Colloidal Flotation

Energy Technology Data Exchange (ETDEWEB)

Jung, In Ha; Lee, Jung Won [Korea Atomic Energy Research Institute, Taejon (Korea)

1998-09-30

Simulated waste liquid containing 50 ppm cobalt ion was treated by adsorbing colloidal flotation using Fe(III) or Al(III) as flocculant and a sodium lauryl sulfate as a collector. Parameters such as pH, surfactant concentration, Fe(III) or Al(III) concentration, gas flow rate, etc., were considered. The flotation with Fe(III) showed 99.8% removal efficiency of cobalt on the conditions of initial cobalt ion concentration 50 ppm, pH 9.5, gas flow rate 70 ml/min, and flotation time 30 min. When the waste solution was treated with 35% H{sub 2}O{sub 2} prior to adsorbing colloidal flotation, the optimal pH for removing cobalt shifted to weak alkaline range and flotation could be applied in wider range of pH as compared to non-use of H{sub 2}O{sub 2}. Additional use of 20 ppm Al(III) after precipitation of 50 ppm Co(II) with 50 ppm Fe(III) made the optimal pH range for preferable flotation wider. Foreign ions such as, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, Na{sup +}, Ca{sup 2+} were adopted and their effects were observed, Of which sulfate ion was found to be detrimental to removal of cobalt ion by flotation. Coprecipitation of Co ion with Fe(III) and Al(III) resulted in better removal efficiency of cobalt ion in the presence of sulfate ion. (author). 14 refs., 13 figs.

Influence of substituents in meso-aryl groups of iron l-oxo porphyrins\

Czech Academy of Sciences Publication Activity Database

Tabor, Edyta; Poltowicz, J.; Pamin, K.; Basag, S.; Kubiak, W.

2016-01-01

Roč. 119, NOV 2016 (2016), s. 342-349 ISSN 0277-5387 Institutional support: RVO:61388955 Keywords : iron porphyrins * μ-Oxo porphyrins * oxidation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.926, year: 2016

The quantitation of 2-oxo-3-hydroxy lysergic acid diethylamide (O-H-LSD) in human urine specimens, a metabolite of LSD: comparative analysis using liquid chromatography-selected ion monitoring mass spectrometry and liquid chromatography-ion trap mass spectrometry.

Science.gov (United States)

Poch, G K; Klette, K L; Anderson, C

2000-04-01

This paper compares the potential forensic application of two sensitive and rapid procedures (liquid chromatography-mass spectrometry and liquid chromatography-ion trap mass spectrometry) for the detection and quantitation of 2-oxo-3-hydroxy lysergic acid diethylamide (O-H-LSD) a major LSD metabolite. O-H-LSD calibration curves for both procedures were linear over the concentration range 0-8,000 pg/mL with correlation coefficients (r2) greater than 0.99. The observed limit of detection (LOD) and limit of quantitation (LOQ) for O-H-LSD in both procedures was 400 pg/mL. Sixty-eight human urine specimens that had previously been found to contain LSD by gas chromatography-mass spectrometry were reanalyzed by both procedures for LSD and O-H-LSD. These specimens contained a mean concentration of O-H-LSD approximately 16 times higher than the LSD concentration. Because both LC methods produce similar results, either procedure can be readily adapted to O-H-LSD analysis for use in high-volume drug-testing laboratories. In addition, the possibility of significantly increasing the LSD detection time window by targeting this major LSD metabolite for analysis may influence other drug-free workplace programs to test for LSD.

Synthesis and crystal structures of 2-methyl-4-aryl-5-oxo-5H-indeno [1,2-b] pyridine carboxylate derivatives

DEFF Research Database (Denmark)

Pandian, Ramesh; Naushad, Edayadulla; Vijayakumar, Vinodhkumar

2014-01-01

pyridine derivatives through oxidation. Consequently, the interest in this aromatization reaction, investigation of a wide range of 1, 4-DHPs continues to attract the attention of researchers. Herein, we report the preparation of pyridine derivatives and the crystal structures determined by X......-ray crystallographic methods.Results: The crystal structures and conformational studies of two organic compounds, namely ethyl 2-methyl-4-phenyl-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate (I) and ethyl 2-methyl-4-(4 chlorophenyl)-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate (II) are reported. The terminal ethyl......) dimer running along 011 direction.Conclusion: The crystal structures ethyl 2-methyl-4-phenyl-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate and ethyl 2-methyl-4-(4 chlorophenyl)-5-oxo-5H-indeno [1,2-b] pyridine-3-carboxylate have been investigated in detail. The terminal ethyl group of compound I...

Liquid-liquid extraction of ion-association complexes of cobalt(II-4-(2-pyridylazoresorcinol with ditetrazolium salts

Directory of Open Access Journals (Sweden)

Divarova Vidka V.

2015-01-01

Full Text Available The formation and liquid-liquid extraction of ion-association complexes between Co(II-4-(2-Pyridylazoresorcinol (PAR anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC, Neotetrazolium chloride (NTC and Nitro Blue Tetrazolium chloride (NBT. The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II-PAR-DTS, the reactants are reacted in molar ratios 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

Energy Technology Data Exchange (ETDEWEB)

Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Division of Inorganic and Physical Chemistry, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, 40132 (Indonesia)

2015-09-30

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

Science.gov (United States)

Asriza, Ristika O.; Arcana, I. Made

2015-09-01

Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

Urinary albumin and 8-oxo-7,8-dihydroguanosine as markers of mortality and cardiovascular disease during 19 years after diagnosis of type 2 diabetes

DEFF Research Database (Denmark)

Broedbaek, Kasper; Køster-Rasmussen, Rasmus; Siersma, Volkert

2017-01-01

,8-dihydroguanosine (8-oxoGuo) that represents intracellular oxidative stress. We investigated the ability of microalbuminuria (MA) and urinary 8-oxoGuo, alone and in combination, to predict mortality and cardiovascular disease (CVD) in patients with type 2 diabetes. We used data from 1381 newly diagnosed diabetes...... patients, and urinary albumin and 8-oxoGuo were assessed in morning urine collected at the time of diabetes diagnosis and at a follow-up visit 6 years later. Associations between the urinary markers and mortality and CVD were assessed in Cox proportional hazards regression models. Test performance......-up. At diagnosis only urinary albumin was associated with CVD. In contrast, only 8-oxoGuo was associated with CVD at 6-year follow-up. When investigating test performance, we found that by combining information from MA and 8-oxoGuo the ability to correctly identify patients at risk could be improved. The findings...

Catalytic activity of γ-irradiated transition metal ions in the decomposition of hydrogen peroxide

International Nuclear Information System (INIS)

Arnikar, H.J.; Kapadi, A.H.; Gohad, A.S.; Bhosale, S.B.

1988-01-01

The catalystic decomposition of hydrogen peroxide by transition metal ions, Fe 2+ , Fe 3+ , Co 2+ and Cu 2+ , adsorbed on neutral α-alumina was studied over the temperature range of 295-313 K. γ-irradiation of the catalysts to a dose of 0.12 MGy enhanced markedly the first order decomposition rate. Negligible in the case of Cu 2+ , the radiation effect increased roughly in the order of the number of unpaired d electrons in these ions: Cu(II), Fe(II), Co(II) and Fe(III). Results are explained on the basis of Kremer's mechanism of electron induced heterogeneous decomposition of H 2 O 2 . The radiation effect is attributed to the initial excess of electrons released from traps in the beginning of the reaction

One-Pot Synthesis of Co-Based Coordination Polymer Nanowire for Li-Ion Batteries with Great Capacity and Stable Cycling Stability

Science.gov (United States)

Wang, Peng; Lou, Xiaobing; Li, Chao; Hu, Xiaoshi; Yang, Qi; Hu, Bingwen

2018-06-01

Nanowire coordination polymer cobalt-terephthalonitrile (Co-BDCN) was successfully synthesized using a simple solvothermal method and applied as anode material for lithium-ion batteries (LIBs). A reversible capacity of 1132 mAh g-1 was retained after 100 cycles at a rate of 100 mA g-1, which should be one of the best LIBs performances among metal organic frameworks and coordination polymers-based anode materials at such a rate. On the basis of the comprehensive structural and morphology characterizations including fourier transform infrared spectroscopy, 1H NMR, 13C NMR, and scanning electron microscopy, we demonstrated that the great electrochemical performance of the as-synthesized Co-BDCN coordination polymer can be attributed to the synergistic effect of metal centers and organic ligands, as well as the stability of the nanowire morphology during cycling.[Figure not available: see fulltext.

Poly(2-hydroxyethyl methacrylate) grafted halloysite nanotubes as a molecular host matrix for luminescent ions prepared by surface-initiated RAFT polymerization and coordination chemistry

Energy Technology Data Exchange (ETDEWEB)

Islam, Md. Rafiqul; Bach, Long Giang; Lim, Kwon Taek, E-mail: ktlim@pknu.ac.kr

2013-07-01

A fluorescent nanohybrid complex comprising of halloysite nanotubes (HNTs), poly(2-hydroxyethyl methacrylate) (PHEMA), and europium ions (Eu{sup 3+}) was synthesized by the combination of surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization and coordination chemistry. Initially, PHEMA was grafted from the HNTs by SI-RAFT and then reacted with succinic anhydride to provide carboxyl acid groups on the external layers of HNTs-g-PHEMA nanohybrids. The subsequent coordination of the nanohybrids with Eu{sup 3+} ions afforded photoluminescent Eu{sup 3+} tagged HNTs-g-PHEMA nanohybrid complexes (HNTs-g-PHEMA-Eu{sup 3+}). The structure, morphology, and fluorescence properties of the Eu{sup 3+} coordinated nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR, XPS, and EDS analyses suggested the formation of the HNTs-g-PHEMA-Eu{sup 3+} nanohybrids. FE-SEM images indicated the immobilization of polymer layers on HNTs. TGA scans further demonstrated the grafting of PHEMA onto HNTs surface. The optical properties of HNTs-g-PHEMA-Eu{sup 3+} nanohybrid complexes were investigated by photoluminescence spectroscopy.

Rational Synthesis of Hollow Prussian Blue Analogue Through Coordination Replication and Controlled-Etching for Cs-Ion Removal.

Science.gov (United States)

Xu, Jun; Bu, Fan-Xing; Guo, Yi-Fei; Zhang, Wei; Hu, Ming; Jiang, Ji-Sen

2018-05-01

Radioactive cesium pollution have received considerable attention due to the increasing risks in development of the nuclear power plants in the world. Although various functional porous materials are utilized to adsorb Cs+ ions in water, Prussian blue analogues (PBAs) are an impressive class of candidates because of their super affinity of Cs+ ions. The adsorption ability of the PBAs strongly relate to the mesostructure and interstitial sites. To design a hollow PBA with large number of interstitial sites, the traditional hollowing methods are not suitable owing to the difficulty in processing the specific PBAs with large number of interstitial sites. In this work, we empolyed a rational strategy which was to form a "metal oxide"@"PBA" core-shell structure via coordination replication at first, then utilized a mild etching to remove the metal oxide core, led to hollow PBA finally. The obtained hollow PBAs were of high crystallinity and large number of interstitial sites, showing a super adsorption performance for Cs+ ions (221.6 mg/g) within a short period (10 min).

Effect of degrading yellow oxo-biodegradable low-density polyethylene films to water quality

Science.gov (United States)

Requejo, B. A.; Pajarito, B. B.

2017-05-01

Polyethylene (PE) contributes largely to plastic wastes that are disposed in aquatic environment as a consequence of its widespread use. In this study, yellow oxo-biodegradable low-density PE films were immersed in deionized water at 50°C for 49 days. Indicators of water quality: pH, oxidation-reduction potential, turbidity, and total dissolved solids (TDS), were monitored at regular intervals. It was observed that pH initially rises and then slowly decreases with time, oxidation-reduction potential decreases then slowly increases with time, turbidity rises above the control at varied rates, and TDS increases abruptly and rises at a hindered rate. Moreover, the films potentially leach out lead chromate. The results imply that degrading oxo-biodegradable LDPE films results to significant reduction of water quality.

Biologically active new Fe(II, Co(II, Ni(II, Cu(II, Zn(II and Cd(II complexes of N-(2-thienylmethylenemethanamine

Directory of Open Access Journals (Sweden)

C. SPÎNU

2008-04-01

Full Text Available Iron(II, cobalt(II, nickel (II, copper (II, zinc(II and cadmium(II complexes of the type ML2Cl2, where M is a metal and L is the Schiff base N-(2-thienylmethylenemethanamine (TNAM formed by the condensation of 2-thiophenecarboxaldehyde and methylamine, were prepared and characterized by elemental analysis as well as magnetic and spectroscopic measurements. The elemental analyses suggest the stoichiometry to be 1:2 (metal:ligand. Magnetic susceptibility data coupled with electronic, ESR and Mössbauer spectra suggest a distorted octahedral structure for the Fe(II, Co(II and Ni(II complexes, a square-planar geometry for the Cu(II compound and a tetrahedral geometry for the Zn(II and Cd(II complexes. The infrared and NMR spectra of the complexes agree with co-ordination to the central metal atom through nitrogen and sulphur atoms. Conductance measurements suggest the non-electrolytic nature of the complexes, except for the Cu(II, Zn(II and Cd(II complexes, which are 1:2 electrolytes. The Schiff base and its metal chelates were screened for their biological activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the metal chelates were found to possess better antibacterial activity than that of the uncomplexed Schiff base.

Development of a Reference Database for Ion Beam Analysis. Report of a Coordinated Research Project on Reference Database for Ion Beam Analysis

International Nuclear Information System (INIS)

2015-12-01

Ion beam analysis techniques are non-destructive analytical techniques used to identify the composition and provide elemental depth profiles in surface layers of materials. The applications of such techniques are diverse and include environmental control, cultural heritage and conservation and fusion technologies. Their reliability and accuracy depends strongly on our knowledge of the nuclear reaction cross sections, and this publication describes the coordinated effort to measure, compile and evaluate cross section data relevant to these techniques and make these data available to the user community through a comprehensive online database. It includes detailed assessments of experimental cross sections as well as attempts to benchmark these data against appropriate integral measurements

Aerogels of 1D Coordination Polymers: From a Non-Porous Metal-Organic Crystal Structure to a Highly Porous Material

Directory of Open Access Journals (Sweden)

Adrián Angulo-Ibáñez

2016-01-01

Full Text Available The processing of an originally non-porous 1D coordination polymer as monolithic gel, xerogel and aerogel is reported as an alternative method to obtain novel metal-organic porous materials, conceptually different to conventional crystalline porous coordination polymer (PCPs or metal-organic frameworks (MOFs. Although the work herein reported is focused upon a particular kind of coordination polymer ([M(μ-ox(4-apy2]n, M: Co(II, Ni(II, the results are of interest in the field of porous materials and of MOFs, as the employed synthetic approach implies that any coordination polymer could be processable as a mesoporous material. The polymerization conditions were fixed to obtain stiff gels at the synthesis stage. Gels were dried at ambient pressure and at supercritical conditions to render well shaped monolithic xerogels and aerogels, respectively. The monolithic shape of the synthesis product is another remarkable result, as it does not require a post-processing or the use of additives or binders. The aerogels of the 1D coordination polymers are featured by exhibiting high pore volumes and diameters ranging in the mesoporous/macroporous regions which endow to these materials the ability to deal with large-sized molecules. The aerogel monoliths present markedly low densities (0.082–0.311 g·cm−3, an aspect of interest for applications that persecute light materials.

Peculiarities of MCD C-term saturation behavior of the exchange coupled Co(II) dimers

International Nuclear Information System (INIS)

Ostrovsky, S.M.

2011-01-01

Graphical abstract: The change of sign of the MCD signal with temperature and magnetic field increase can take place. The origin of this peculiarity is explained by the strong orbital contribution. Highlights: → MCD C-term saturation behavior of the exchange coupled cobalt dimer. → Strong orbital contribution to the magneto-optical behavior. → Change of sign of the MCD signal with temperature and magnetic field increase. - Abstract: The MCD C-term saturation behavior of the exchange coupled octahedrally coordinated cobalt dimers is studied for different types of distortion of the local surrounding of each interacting ion. It was found that in the case of antiferromagnetic exchange interaction the change of sign of the MCD signal with temperature and magnetic field increase can take place. This signal behavior is not the result of overlapping of different electronic transitions and it is characteristic of an individual MCD line. The origin of this magneto-optical behavior is explained by the strong contribution coming from the unquenched orbital angular momenta of interacting cobalt ions. The found peculiarity is inherent to complexes composed of nonequivalent cobalt ions as well as to the dimeric complexes with the equivalent Co ions with nonparallel local axes.

Application of β-cyclodextrin polymers in separation of metal ions

International Nuclear Information System (INIS)

Kozlowski, C.A.; Kozlowska, J.

2006-01-01

In the present work the competitive transport of Cu(II), Co(II), Ni(II) and Zn(II) ions through the plasticized immobilized membranes was studied. β-cyclodextrin (β-CD) polymers have been used as macrocyclic ligands for separation of metal ions from dilute aqueous solutions by ion exchange methods, i.e. transport across polymer inclusion membranes and ion flotation process. β-CD polymers were prepared by cross-linking β-CD with alkenyl (nonenyl) succinic anhydride derivatives, phtalic and 3-nitrophtalic anhydride in anhydrous N,N-dimethylformamide (DMF) resulting in formation of Polymer A, B or C, respectively. In he case of cooper(II) flotation results obtained with the use of nonylphenol polyoxyethyl glycol ether as an non-anionic surfactant and β-CD polymers as complexation agent, show that the removal of metal decreases with higher molecular mass of β-CD polymers linked by phtalic or 3-nitrophtalic anhydrides. For both derivatives with pH increase the copper(II) removed increase. The highest flotation removal, i.e. 93% is observed for β-CD polymers synthesized at 100 o C with molar ratio CD : NaH : 3-nitrophtalic anhydride equal to 1 : 7 : 7

Studies on Some Physical, Chemical and Sorption Properties of Some Inorganic ion Exchangers and Their Application to Radioactive Isotopes Removal

International Nuclear Information System (INIS)

El-Sweify, F.H.; Shehata, M.K.K.; El-Shazly, E.A.A.

1999-01-01

In the present work, amorphous zirconium phosphate, zirconium titanium phosphate and ceric tungstate have been synthesised. Solubility of the prepared ion exchangers in different media has been examined. These media were mineral acids, aqueous solutions of organic acids: oxalic, citric and tartaric as well as ammonium and potassium carbonate solutions of different molarities. I.R. analysis is applied on some samples of the prepared ion exchangers. Sorption behaviour of different metal ion species, of elements of nuclear significance on the prepared ion exchangers has been studied from aqueous media of different compositions and concentration under different experimental conditions. The studied metal ions are, Ce(III) and Eu(III), as representative for the trivalent lanthanides, Co(II), Zr(IV), Nb(V), Hf(IV), Te(IV), Ce(IV), Th(IV) and U(V I). Optimization of the conditions for the isolation and separation of the desired element species highlighted

Synthesis, vibrational spectrometry and thermal characterizations of coordination polymers derived from divalent metal ions and hydroxyl terminated polyurethane as ligand

Science.gov (United States)

Laxmi; Khan, Shabnam; Kareem, Abdul; Zafar, Fahmina; Nishat, Nahid

2018-01-01

A series of novel coordination polyurethanes [HTPU-M, where M = Mn(II) 'd5', Ni(II) 'd8', and Zn(II) 'd10'] have been synthesized to investigate the effect of divalent metal ions coordination on structure, thermal and adsorption properties of low molecular weight hydroxyl terminated polyurethane (HTPU). HTPU-M have been synthesized in situ where, sbnd OH group of HTPU (synthesized by the condensation polymerization reaction of ethylene glycol (EG) and toluene diisocyanate (TDI) in presence of catalyst) on condensation polymerization with metal acetate in presence of acid catalyst synthesized HTPU-M followed by coordination of metal ions with hetero atoms. The structure, composition and geometry of HTPU-M have been confirmed by vibrational spectrometry (FTIR), 1H NMR, elemental analysis and UV-Visible spectroscopy. Morphological structures of HTPU-M were analyzed by X-Ray Diffraction analysis (XRD), Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive X-ray spectroscopy (EDX) and High Resolution Transmission Electron Microscope (HR-TEM) techniques. The thermal degradation pattern and thermal stability of HTPU-M in comparison to HTPU was investigated by thermal-gravimetric (TG)/differential thermal (DT), analyses along with Integral procedure decomposition temperature (IPDT) by Doyle method. The molecular weight of HTPU was determined by gel permeation chromatography (GPC). The preliminary adsorption/desorption studies of HTPU-M for Congo red (CR) was studied by batch adsorption techniques. The results indicated that HTPU-M have amorphous, layered morphology with higher number of nano-sized grooves in comparison to HTPU. Coordination of metal to HTPU plays a key role in enhancing the thermal stability [HTPU-Ni(II) > HTPU-Mn(II) > HTPU-Zn(II) > HTPU]. The HTPU-M can be utilized for industrial waste water treatment by removing environmental pollutants.

Metabolic characteristics of 13-cis-retinoic acid (isotretinoin) and anti-tumour activity of the 13-cis-retinoic acid metabolite 4-oxo-13-cis-retinoic acid in neuroblastoma.

Science.gov (United States)

Sonawane, Poonam; Cho, Hwang Eui; Tagde, Ashujit; Verlekar, Dattesh; Yu, Alice L; Reynolds, C Patrick; Kang, Min H

2014-12-01

Isotretinoin (13-cis-retinoic acid; 13-cRA) is a differentiation inducer used to treat minimal residual disease after myeloablative therapy for high-risk neuroblastoma. However, more than 40% of children develop recurrent disease during or after 13-cRA treatment. The plasma concentrations of 13-cRA in earlier studies were considered subtherapeutic while 4-oxo-13-cis-RA (4-oxo-13-cRA), a metabolite of 13-cRA considered by some investigators as inactive, were greater than threefold higher than 13-cRA. We sought to define the metabolic pathways of 13-cRA and investigated the anti-tumour activity of its major metabolite, 4-oxo-13-cRA. Effects of 13-cRA and 4-oxo-13-cRA on human neuroblastoma cell lines were assessed by DIMSCAN and flow cytometry for cell proliferation, MYCN down-regulation by reverse transcription PCR and immunoblotting, and neurite outgrowth by confocal microscopy. 13-cRA metabolism was determined using tandem MS in human liver microsomes and in patient samples. Six major metabolites of 13-cRA were identified in patient samples. Of these, 4-oxo-13-cRA was the most abundant, and 4-oxo-13-cRA glucuronide was also detected at a higher level in patients. CYP3A4 was shown to play a major role in catalysing 13-cRA to 4-oxo-13-cRA. In human neuroblastoma cell lines, 4-oxo-13-cRA and 13-cRA were equi-effective at inducing neurite outgrowth, inhibiting proliferation, decreasing MYCN mRNA and protein, and increasing the expression of retinoic acid receptor-β mRNA and protein levels. We showed that 4-oxo-13-cRA is as active as 13-cRA against neuroblastoma cell lines. Plasma levels of both 13-cRA and 4-oxo-13-cRA should be evaluated in pharmacokinetic studies of isotretinoin in neuroblastoma. © 2014 The British Pharmacological Society.

The Recently Identified Isoleucine Conjugate of cis-12-Oxo-Phytodienoic Acid Is Partially Active in cis-12-Oxo-Phytodienoic Acid-Specific Gene Expression of Arabidopsis thaliana

Czech Academy of Sciences Publication Activity Database

Arnold, M.D.; Gruber, C.; Floková, Kristýna; Miersch, Otto; Strnad, Miroslav; Novák, Ondřej; Wasternack, Claus; Hause, B.

2016-01-01

Roč. 11, č. 9 (2016), e0162829 E-ISSN 1932-6203 R&D Projects: GA ČR GA14-34792S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : ALLENE-OXIDE-CYCLASE * 12-OXO-PHYTODIENOIC ACID * JASMONIC ACID Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.806, year: 2016

Synthesis, crystal structure, antibacterial activity and theoretical studies on a novel mononuclear cobalt(II) complex based on 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand

Science.gov (United States)

Maghami, Mahboobeh; Farzaneh, Faezeh; Simpson, Jim; Ghiasi, Mina; Azarkish, Mohammad

2015-08-01

A cobalt complex was prepared from CoCl2·6H2O and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) in methanol and designated as [Co(tptz)(CH3OH)Cl2]·CH3OH·0.5H2O (1). It was characterized by several techniques including TGA analysis and FT-IR, UV-Vis and 1H NMR spectral studies. The crystal structure of 1 was determined by single-crystal X-ray diffraction. The Co(II) metal center in 1 is six coordinated with a distorted octahedral geometry. The tptz ligand is tridentate and coordinates to the cobalt through coplanar nitrogen atoms from the triazine and two pyridyl rings. Two chloride anions and a methanol molecule complete the inner coordination sphere of the metal ion. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single XRD data. The in vitro antibacterial activity of various tptz complexes of Co(II), Ni(II), Cu(II), Mn(II) and Rh(III) were evaluated against Gram-positive (Bacillus subtilis, Staphylococcus aureus and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Whereas all complexes exhibited good activity in comparison to standard antibacterial drugs, the inhibitory effects of complexes were found to be more than that of the parent ligand. Overall, the obtained results strongly suggest that the cobalt(II) complex is a suitable candidate for counteracting antibiotic resistant microorganisms.

π-Stacking and hydrogen bonding in catena-poly[[4,4 '-bipyridine-κN)-dioxouranium(VI)]-di-μ-hydroxo

International Nuclear Information System (INIS)

Thuery, P.

2007-01-01

The title compound, [UO 2 (OH) 2 (C 10 H 8 N 2 )] n , was obtained under hydrothermal conditions. The U atom is seven-coordinated and its environment is pentagonal bipyramidal, with the oxo atoms in axial positions, and one N atom and four hydroxide groups in the equatorial plane. The hydroxide ions are bridging, which results in the formation of infinite chains with the bipyridine molecules alternately located on either side. Neighbouring chains interpenetrate so that each bipyridine ligand is involved both in hydrogen bonds with two hydroxide ions and in π-stacking with its two neighbours from the next chain. (authors)

Measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-guanosine in cerebrospinal fluid by ultra performance liquid chromatography-tandem mass spectrometry

DEFF Research Database (Denmark)

Weimann, Allan; Simonsen, Anja Hviid; Poulsen, Henrik E

2018-01-01

absolute concentrations varying by a factor >105 in healthy humans. This could indicate that there is a serious specificity problem in some of the methods. In this paper an isotope-dilution UPLC-MS/MS method with high specificity and sensitivity for the quantification of 8oxoGuo and 8oxodGuo in CSF...

Cadmium, cobalt and lead cause stress response, cell cycle deregulation and increased steroid as well as xenobiotic metabolism in primary normal human bronchial epithelial cells which is coordinated by at least nine transcription factors

Energy Technology Data Exchange (ETDEWEB)

Glahn, Felix; Wiese, Jan; Foth, Heidi [Martin-Luther-University, Halle-Wittenberg, Institute of Environmental Toxicology, Halle/Saale (Germany); Schmidt-Heck, Wolfgang; Guthke, Reinhard [Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena (Germany); Zellmer, Sebastian; Gebhardt, Rolf [University of Leipzig, Institute of Biochemistry, Medical Faculty, Leipzig (Germany); Golka, Klaus; Degen, Gisela H.; Hermes, Matthias; Schormann, Wiebke; Brulport, Marc; Bauer, Alexander; Bedawy, Essam [IfADo, Leibniz Research Centre for Working Environment and Human Factors, Dortmund (Germany); Hergenroeder, Roland [ISAS, Institute for Analytical Sciences, Dortmund (Germany); Lehmann, Thomas [Translational Centre for Regenerative Medicine, Leipzig (Germany); Hengstler, Jan G. [IfADo, Leibniz Research Centre for Working Environment and Human Factors, Dortmund (Germany)

2008-08-15

Workers occupationally exposed to cadmium, cobalt and lead have been reported to have increased levels of DNA damage. To analyze whether in vivo relevant concentrations of heavy metals cause systematic alterations in RNA expression patterns, we performed a gene array study using primary normal human bronchial epithelial cells. Cells were incubated with 15{mu}g/l Cd(II), 25{mu}g/l Co(II) and 550{mu}g/l Pb(II) either with individual substances or in combination. Differentially expressed genes were filtered out and used to identify enriched GO categories as well as KEGG pathways and to identify transcription factors whose binding sites are enriched in a given set of promoters. Interestingly, combined exposure to Cd(II), Co(II) and Pb(II) caused a coordinated response of at least seven stress response-related transcription factors, namely Oct-1, HIC1, TGIF, CREB, ATF4, SRF and YY1. A stress response was further corroborated by up regulation of genes involved in glutathione metabolism. A second major response to heavy metal exposure was deregulation of the cell cycle as evidenced by down regulation of the transcription factors ELK-1 and the Ets transcription factor GABP, as well as deregulation of genes involved in purine and pyrimidine metabolism. A third and surprising response was up regulation of genes involved in steroid metabolism, whereby promoter analysis identified up regulation of SRY that is known to play a role in sex determination. A forth response was up regulation of xenobiotic metabolising enzymes, particularly of dihydrodiol dehydrogenases 1 and 2 (AKR1C1, AKR1C2). Incubations with individual heavy metals showed that the response of AKR1C1 and AKR1C2 was predominantly caused by lead. In conclusion, we have shown that in vivo relevant concentrations of Cd(II), Co(II) and Pb(II) cause a complex and coordinated response in normal human bronchial epithelial cells. This study gives an overview of the most responsive genes. (orig.)

Adsorption of Cs(I), Sr(II), Eu(III), Co(II) and Cd(II) by Al2O3

International Nuclear Information System (INIS)

Shiao, S.Y.; Egozy, Y.; Meyer, R.E.

1981-01-01

Adsorption of Cs(I), Sr(II), Eu(III), Co(II) and Cd(II) by Al 2 O 3 was carried out over a wide range of NaCl concentration and solution pH. In the medium pH region (pH 5 to 9), adsorption depends strongly on pH and less on salt concentration. However, in the high pH region (pH above 9), the salt dependence of the distribution coefficient becomes important. (author)

Physico - chemical investigation on Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO2+2 and VO+2 ions-O-(-N-3,5-dichloro-α-pyridone imino)

International Nuclear Information System (INIS)

Mathur, Praveen; Trivedi, Pradeep; Mehta, R.K.

1983-01-01

Studies on the interaction of newly synthesised ligand, O-(N-3, 5-dichloro-α-pyridone imino) benzene sulphonic acid (H 2 PB) with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO 2 +2 and VO +2 have been carried out potentiometrically. Many physico-chemical studies on thermodynamics, elemental analysis, molecular weight, magnetic moment, conductance, electronic and IR spectra have also been made on the solid chelates and their adducts. The dissociation constants of H 2 PB and stabilities of its bivalent chelates have been evaluated potentiometrically at 25deg, 35deg and 45degC in aqueous medium (0.01M, 0.05M and 0.1M NaClO 4 ) by Bjerrum's method. The stability sequence is in agreement with the Irving-William's rule. (author)

Synthesis, screening and QSAR studies of 3-benzoyl-2-oxo/thioxo-1 ...

African Journals Online (AJOL)

5-Acyl-6-methyl-4-substituted-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidines (A) were synthesized by cyclocondensation reaction between appropriate aldehyde, acetoacetate and urea/thiourea in presence of aluminium chloride and hydrochloric acid which upon treatment with benzoyl chloride in presence of pyridine in ...

Insulin fibrillation: The influence and coordination of Zn2+

DEFF Research Database (Denmark)

Frankær, Christian Grundahl; Sønderby, Pernille; Bang, Maria Blanner

2017-01-01

fibrils has been debated for some years. We have therefore investigated the influence and binding geometry of zinc in fibrillated insulin using extended X-ray absorption fine-structure and X-ray absorption near-edge structure spectroscopy. The results were validated with fibre diffraction, Transmission...... Electron Microscopy and Thioflavin T fluorescence measurements. It is well-known that Zn2+ ions coordinate and stabilize the hexameric forms of insulin. However, this study is the first to show that zinc indeed binds to the insulin fibrils. Furthermore, zinc influences the kinetics and the morphology...... of the fibrils. It also shows that zinc coordinates to histidine residues in an environment, which is similar to the coordination seen in the insulin R6 hexamers, where three histidine residues and a chloride ion is coordinating the zinc....

Alkali metal and ammonium fluoro(trifluoroacetato)metallates M'[ M''3(μ3-F)(CF3COO)6(CF3COOH)3], where M' = Li, Na, K, NH4, Rb, or Cs and M'' = Ni or Co. Synthesis and crystal structures

Science.gov (United States)

Tereshchenko, D. S.; Morozov, I. V.; Boltalin, A. I.; Karpova, E. V.; Glazunova, T. Yu.; Troyanov, S. I.

2013-01-01

A series of fluoro(trifluoroacetato)metallates were synthesized by crystallization from solutions in trifluoroacetic acid containing nickel(II) or cobalt(II) nitrate hydrates and alkali metal or ammonium fluorides: Li[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)3 ( I), M'[Ni3(μ3-F)(CF3COO)6(CF3COOH)3] ( M' = Na ( II), NH4 ( IV), Rb ( V), and Cs ( VI)), NH4[Co3(μ3-F) (CF3COO)6(CF3COOH)3] ( III), and Cs[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)0.5 ( VII). The crystal structures of these compounds were determined by single-crystal X-ray diffraction. All structures contain triangular trinuclear complex anions [ M 3″(μ3-F)(CF3COO)6(CF3COOH)3]- ( M″ = Ni, Co) structurally similar to trinuclear 3d metal oxo carboxylate complexes. The three-coordinated F atom is located at the center of the triangle formed by Ni(II) or Co(II) atoms. The metal atoms are linked in pairs by six bridging trifluoroacetate groups located above and below the plane of the [ M″3 F] triangle. The oxygen atoms of the axial CF3COOH molecules complete the coordination environment of M″ atoms to an octahedron.

Syntheses and crystal structures of two novel alkaline uranyl chromates A2(UO2)(CrO4)2 (A=Rb, Cs) with bidentate coordination mode of uranyl ions by chromate anions

International Nuclear Information System (INIS)

Siidra, Oleg I.; Nazarchuk, Evgeny V.; Krivovichev, Sergey V.

2012-01-01

Single crystals of Cs 2 (UO 2 )(CrO 4 ) 2 and Rb 2 (UO 2 )(CrO 4 ) 2 were prepared by solid state reactions. The structures are based upon the [(UO 2 )(CrO 4 ) 2 ] 2− chains. Within the chains, UrO 5 pentagonal bipyramids (Ur=uranyl) form Ur 2 O 8 dimers, which are linked via CrO 4 tetrahedra into one-dimensional chains. The CrO 4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion, which is unusual for uranyl chromates. The bidentate coordination has a strong influence upon geometrical parameters of both U and Cr coordination polyhedra. The conformation of the chains in 1 and 2 is different due to the different size of the Cs + and Rb + cations. - Graphical abstract: Uranyl chromate chain with monodentate and bidentate coordination mode of uranyl cations by CrO 4 tetrahedra in Cs 2 (UO 2 )(CrO 4 ) 2 . Highlights: ► Single crystals of novel uranyl chromates were prepared by solid state reactions. ► The CrO 4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion. ►The bidentate coordination has a strong influence upon geometrical parameters.

Crystal structure of tetraaquabis(8-chloro-9,10-dioxo-9,10-dihydroanthracene-1-carboxylato-κO1cobalt(II dihydrate

Directory of Open Access Journals (Sweden)

Wen-Juan Cai

2014-10-01

Full Text Available In the title complex, [Co(C15H6ClO42(H2O4]·2H2O, the CoII ion is bound by two carboxylate O atoms of two 5-chloro-9,10-anthraquinone-1-carboxylate anions and four water O atoms in a trans conformation, forming an irregular octahedral coordination geometry. This arrangement is stabilized by intramolecular O—H...O hydrogen bonds between water and carboxylate. Further O—H...O hydrogen bonds between coordinating and non-coordinating water and carboxylate produce layers of molecules that extend parallel to (001. The organic ligands project above and below the plane. Those ligands of adjacent planes are interdigitated and there are π–π interactions between them with centroid–centroid distances of 3.552 (2 and 3.767 (2 Å that generate a three-dimensional supramolecular structure.

Label-free colorimetric detection of mercury via Hg2+ ions-accelerated structural transformation of nanoscale metal-oxo clusters

Science.gov (United States)

Chen, Kun; She, Shan; Zhang, Jiangwei; Bayaguud, Aruuhan; Wei, Yongge

2015-11-01

Mercury and its compounds are known to be extremely toxic but widely distributed in environment. Although many works have been reported to efficiently detect mercury, development of simple and convenient sensors is still longed for quick analyzing mercury in water. In this work, a nanoscale metal-oxo cluster, (n-Bu4N)2[Mo5NaO13(OCH3)4(NO)], (MLPOM), organically-derivatized from monolacunary Lindqvist-type polyoxomolybdate, is found to specifically react with Hg2+ in methanol/water via structural transformation. The MLPOM methanol solution displays a color change from purple to brown within seconds after being mixed with an aqueous solution containing Hg2+. By comparing the structure of polyoxomolybdate before and after reaction, the color change is revealed to be the essentially structural transformation of MLPOM accelerated by Hg2+. Based on this discovery, MLPOM could be utilized as a colorimetric sensor to sense the existence of Hg2+, and a simple and label-free method is developed to selectively detect aqueous Hg2+. Furthermore, the colorimetric sensor has been applied to indicating mercury contamination in industrial sewage.

Photoactive devices including porphyrinoids with coordinating additives

Science.gov (United States)

Forrest, Stephen R; Zimmerman, Jeramy; Yu, Eric K; Thompson, Mark E; Trinh, Cong; Whited, Matthew; Diev, Vlacheslav

2015-05-12

Coordinating additives are included in porphyrinoid-based materials to promote intermolecular organization and improve one or more photoelectric characteristics of the materials. The coordinating additives are selected from fullerene compounds and organic compounds having free electron pairs. Combinations of different coordinating additives can be used to tailor the characteristic properties of such porphyrinoid-based materials, including porphyrin oligomers. Bidentate ligands are one type of coordinating additive that can form coordination bonds with a central metal ion of two different porphyrinoid compounds to promote porphyrinoid alignment and/or pi-stacking. The coordinating additives can shift the absorption spectrum of a photoactive material toward higher wavelengths, increase the external quantum efficiency of the material, or both.

Anhydrous thallium hydrogen L-glutamate: polymer networks formed by sandwich layers of oxygen-coordinated thallium ions cores shielded by hydrogen L-glutamate counterions.

Science.gov (United States)

Bodner, Thomas; Wirnsberger, Bianca; Albering, Jörg; Wiesbrock, Frank

2011-11-07

Anhydrous thallium hydrogen L-glutamate [Tl(L-GluH)] crystallizes from water (space group P2(1)) with a layer structure in which the thallium ions are penta- and hexacoordinated exclusively by the oxygen atoms of the γ-carboxylate group of the hydrogen L-glutamate anions to form a two-dimensional coordination polymer. The thallium-oxygen layer is composed of Tl(2)O(2) and TlCO(2) quadrangles and is only 3 Å high. Only one hemisphere of the thallium ions participates in coordination, indicative of the presence of the 6s(2) lone pair of electrons. The thallium-oxygen assemblies are shielded by the hydrogen l-glutamate anions. Only the carbon atom of the α-carboxylate group deviates from the plane spanned by the thallium ions, the γ-carboxylate groups and the proton bearing carbon atoms, which are in trans conformation. Given the abundance of L-glutamic and L-aspartic acid in biological systems on the one hand and the high toxicity of thallium on the other hand, it is worth mentioning that the dominant structural motifs in the crystal structure of [Tl(L-GluH)] strongly resemble their corresponding analogues in the crystalline phase of [K(L-AspH)(H(2)O)(2)].

Detection of the electronic structure of iron-(iii)-oxo oligomers forming in aqueous solutions.

Science.gov (United States)

Seidel, Robert; Kraffert, Katrin; Kabelitz, Anke; Pohl, Marvin N; Kraehnert, Ralph; Emmerling, Franziska; Winter, Bernd

2017-12-13

The nature of the small iron-oxo oligomers in iron-(iii) aqueous solutions has a determining effect on the chemical processes that govern the formation of nanoparticles in aqueous phase. Here we report on a liquid-jet photoelectron-spectroscopy experiment for the investigation of the electronic structure of the occurring iron-oxo oligomers in FeCl 3 aqueous solutions. The only iron species in the as-prepared 0.75 M solution are Fe 3+ monomers. Addition of NaOH initiates Fe 3+ hydrolysis which is followed by the formation of iron-oxo oligomers. At small enough NaOH concentrations, corresponding to approximately [OH]/[Fe] = 0.2-0.25 ratio, the iron oligomers can be stabilized for several hours without engaging in further aggregation. Here, we apply a combination of non-resonant as well as iron 2p and oxygen 1s resonant photoelectron spectroscopy from a liquid microjet to detect the electronic structure of the occurring species. Specifically, the oxygen 1s partial electron yield X-ray absorption (PEY-XA) spectra are found to exhibit a peak well below the onset of liquid water and OH - (aq) absorption. The iron 2p absorption gives rise to signal centered between the main absorption bands typical for aqueous Fe 3+ . Absorption bands in both PEY-XA spectra are found to correlate with an enhanced photoelectron peak near 20 eV binding energy, which demonstrates the sensitivity of resonant photoelectron (RPE) spectroscopy to mixing between iron and ligand orbitals. These various signals from the iron-oxo oligomers exhibit maximum intensity at [OH]/[Fe] = 0.25 ratio. For the same ratio, we observe changes in the pH as well as in complementary Raman spectra, which can be assigned to the transition from monomeric to oligomeric species. At approximately [OH]/[Fe] = 0.3 we begin to observe particles larger than 1 nm in radius, detected by small-angle X-ray scattering.

Detection of mitochondrial COII DNA sequences in ant guts as a method for assessing termite predation by ants

Czech Academy of Sciences Publication Activity Database

Fayle, Tom Maurice; Scholtz, O.; Dumbrell, A. J.; Russell, S.; Segar, Simon Tristram; Eggleton, P.

2015-01-01

Roč. 10, č. 4 (2015), e0122533 E-ISSN 1932-6203 R&D Projects: GA ČR GA14-32302S Grant - others:European Social Fund(CZ) CZ1.07/2.3.00/20.0064; European Social Fund(CZ) CZ.1.07/2.3.00/30.0006 Institutional support: RVO:60077344 Keywords : mitochondrial COII DNA sequences Subject RIV: EH - Ecology, Behaviour Impact factor: 3.057, year: 2015 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0122533

synthesis and optical properties of self-assembled coordination ...

African Journals Online (AJOL)

The coordination chemistry of the phenylmalonic acid and 4-1H- amino- 1,2,4- triazole with Zn(II) ions has been investigated. The coordination polymer was synthesized by slow evaporation method and characterized by FT-infrared spectroscopy, ultraviolet-visible measurements, scanning electron microscopy, Electron ...

Reversible Capture and Release of Cl2 and Br2 with a Redox-Active Metal-Organic Framework.

Science.gov (United States)

Tulchinsky, Yuri; Hendon, Christopher H; Lomachenko, Kirill A; Borfecchia, Elisa; Melot, Brent C; Hudson, Matthew R; Tarver, Jacob D; Korzyński, Maciej D; Stubbs, Amanda W; Kagan, Jacob J; Lamberti, Carlo; Brown, Craig M; Dincă, Mircea

2017-04-26

Extreme toxicity, corrosiveness, and volatility pose serious challenges for the safe storage and transportation of elemental chlorine and bromine, which play critical roles in the chemical industry. Solid materials capable of forming stable nonvolatile compounds upon reaction with elemental halogens may partially mitigate these challenges by allowing safe halogen release on demand. Here we demonstrate that elemental halogens quantitatively oxidize coordinatively unsaturated Co(II) ions in a robust azolate metal-organic framework (MOF) to produce stable and safe-to-handle Co(III) materials featuring terminal Co(III)-halogen bonds. Thermal treatment of the oxidized MOF causes homolytic cleavage of the Co(III)-halogen bonds, reduction to Co(II), and concomitant release of elemental halogens. The reversible chemical storage and thermal release of elemental halogens occur with no significant losses of structural integrity, as the parent cobaltous MOF retains its crystallinity and porosity even after three oxidation/reduction cycles. These results highlight a material operating via redox mechanism that may find utility in the storage and capture of other noxious and corrosive gases.

Non-traditional Oxidants in Preparative Coordination Chemistry

Science.gov (United States)

Kukushkin, Vadim Yu; Kukushkin, Yurii N.

1986-10-01

The application of nitrosonium and arenediazonium salts, carbenium, silver(I), and mercury(II) ions, protic acids, and amine oxides as oxidants in preparative coordination chemistry is examined. Specific examples illustrate which problems in the field of the synthesis and reactions of coordination compounds can be solved with the aid of these oxidants. The bibliography includes 158 references.

Neutron activation analysis for chemical characterization of Brazilian oxo-biodegradable plastics

International Nuclear Information System (INIS)

Mateus Eugenio Boscaro; De Nadai Fernandes, E.A.; Marcio Arruda Bacchi; Luis Gustavo Cofani dos Santos; Cofani dos Santos, S.N.S.; Sandra Mara Martins-Franchetti

2015-01-01

The chemical characterization of oxo-biodegradable plastic bags was performed by neutron activation analysis. The presence of several chemical elements (As, Br, Ca, Co, Cr, Fe, Hf, K, La, Na, Sb, Sc, Ta and Zn) with large variability of mass fractions amongst samples indicates that these plastics receive additives and may have been contaminated during manufacturing process thereby becoming potential environmental pollutants. (author)

Synthesis, spectroscopic characterization, biological studies and DFT calculations on some transition metal complexes of NO donor ligand

Science.gov (United States)

Zordok, W. A.; Sadeek, S. A.

2018-04-01

Seven new complexes of2-oxo-4,6-diphenyl-1,2-dihyropyridine-3-carbonitrile (L) with Fe(III), Co(II), Cu(II), Zn(II), Y(III), Zr(IV) and La(III) were synthesized. The isolated solid compounds were elucidated from micro analytical, IR, electronic, mass, 1H NMR, magnetic susceptibility measurements and TG/DTG, DTA analyses. The intensity of ν(Ctbnd N) was changed to strong and shifted to around 2200 cm-1. Also, the ν(Cdbnd O) was shifted to higher frequency value (1644 cm-1). The spectra of the complexes indicate that the free ligand is coordinated to the metal ions via nitrogen of carbonitrile group and oxygen of keto group. From DFT calculations the Cu(II) and Fe(III) complexes behave as regular octahedral, while other complexes are distorted octahedral. The value of energy gap of the free ligand (ΔE = 0.3343 eV) is greater than all new complexes, so they are more reactive than free ligand, also the Fe(III) complex (ΔE = 0.0985 eV) is the most reactive complex, while Cu(II) complex (ΔE = 0.3219 eV) is the least reactive complex. The LMCT in case of Zr(IV) complex was resulted from transitions from HOMO-2 (62%), HOMO-1 (16%)and HOMO (25%), while the d-d transition in Fe(III) complex was resulted from HOMO-1(30%), HOMO-2(62%) and HOMO(30%). Also, the metal complexes exhibit antibacterial activity for Gram-positive and Gram-negative and antifungal activity. The Y(III) and Cu(II) complexes are highly significant for Escherichia coli and salmonella typhimurium.

16-Cyclopentadienyl tricarbonyl 99mTc 16-oxo-hexadecanoic acid: synthesis and evaluation of fatty acid metabolism in mouse myocardium.

Science.gov (United States)

Lee, Byung Chul; Kim, Dong Hyun; Lee, Iljung; Choe, Yearn Seong; Chi, Dae Yoon; Lee, Kyung-Han; Choi, Yong; Kim, Byung-Tae

2008-06-26

We synthesized 16-cyclopentadienyl tricarbonyl 99mTc 16-oxo-hexadecanoic acid (99mTc-CpTT-16-oxo-HDA, 1) and investigated its potential as a radiotracer for evaluating fatty acid metabolism in myocardium. Radiotracer 1 was synthesized in 22.6 +/- 6.3% decay-corrected yield by a double ligand transfer reaction between the ferrocene adduct of methyl hexadecanoate ( 2) and Na99mTcO 4 in the presence of Cr(CO)6 and CrCl3, followed by hydrolysis of the methyl ester group. Radiotracer 1 was found to be chemically stable (99% at 6 h) when incubated in human serum. A tissue distribution study in mice showed that high radioactivity accumulated in heart (9.03%ID/g at 1 min and 5.41%ID/g at 5 min postinjection) with rapid clearance and that heart to blood uptake ratios increased with time (2.13 at 5 min and 3.76 at 30 min postinjection). Metabolite analysis of the heart tissues using a simple extraction method showed that 99mTc-CpTT-4-oxo-butyric acid was detected as the major radioactive metabolite by HPLC, suggesting that 1 is metabolized to 99mTc-CpTT-4-oxo-butyric acid via beta-oxidation in myocardium.

Ion-ion and ion-solvent interactions in lithium imidazolide electrolytes studied by Raman spectroscopy and DFT models.

Science.gov (United States)

Scheers, Johan; Niedzicki, Leszek; Zukowska, Grażyna Z; Johansson, Patrik; Wieczorek, Władysław; Jacobsson, Per

2011-06-21

Molecular level interactions are of crucial importance for the transport properties and overall performance of ion conducting electrolytes. In this work we explore ion-ion and ion-solvent interactions in liquid and solid polymer electrolytes of lithium 4,5-dicyano-(2-trifluoromethyl)imidazolide (LiTDI)-a promising salt for lithium battery applications-using Raman spectroscopy and density functional theory calculations. High concentrations of ion associates are found in LiTDI:acetonitrile electrolytes, the vibrational signatures of which are transferable to PEO-based LiTDI electrolytes. The origins of the spectroscopic changes are interpreted by comparing experimental spectra with simulated Raman spectra of model structures. Simple ion pair models in vacuum identify the imidazole nitrogen atom of the TDI anion to be the most important coordination site for Li(+), however, including implicit or explicit solvent effects lead to qualitative changes in the coordination geometry and improved correlation of experimental and simulated Raman spectra. To model larger aggregates, solvent effects are found to be crucial, and we finally suggest possible triplet and dimer ionic structures in the investigated electrolytes. In addition, the effects of introducing water into the electrolytes-via a hydrate form of LiTDI-are discussed.

Reaction of uranyl nitrate with carboxylic di-acids under hydrothermal conditions. Crystal structure of complexes with L(+)-tartaric and oxalic acids

International Nuclear Information System (INIS)

Thuery, P.

2007-01-01

L(+)-tartaric acid reacts with uranyl nitrate in the presence of KOH, under mild hydrothermal conditions, to give the complex [UO 2 (C 4 H 4 O 6 )(H 2 O)] (1), the first uranyl tartrate to be crystallographically characterized. Each tartrate ligand bridges three uranyl ions, one of them in chelating fashion through proximal carboxylate and hydroxyl groups. The resulting assemblage is two-dimensional, with the uranyl pentagonal bipyramidal coordination polyhedra separated from one another. Prolonged heating of an uranyl tartrate solution resulted in oxidative cleavage of the acid and formation of the oxalate complex [(UO 2 ) 2 (C 2 O 4 ) 2 (OH)Na(H 2 O) 2 ] (2). The bis-bidentate oxalate and bridging hydroxide groups ensure the formation of sheets with corner-sharing uranyl pentagonal bipyramidal coordination polyhedra, in which six-membered metallacycles encompass the sodium ions. These sheets are assembled into a three-dimensional framework through further oxo-bonding of the sodium ions. (authors)

Synthesis, NMR characterization, X-ray crystal structure of Co(II) Ni(II) and Cu(II) complexes of a pyridine containing self-assembling

International Nuclear Information System (INIS)

Ranjbar, M.; Taghavipour, M.; Moghimi, A.; Aghabozorg, H.

2002-01-01

In the recent years, the self-assembling systems have been attracted chemists. The intermolecular bond in such systems mainly consists of ion pairing and hydrogen bonding [1,2]. The reaction between self-assembling system liquid LH 2 (py dc=2,6-pyridinedicarboxylic acid and py da=2,6- pyridine diamin) with cobalt (II) nitrate, nickel (II) chloride, and copper (II) acetate in water leads to the formation of self- assemble coordination complexes, [py da.H] 2 [M(py dc) 2 ]. H 2 O, M=Co(II),Ni(II), and Cu(II). The characterization was performed using elemental analysis, ESI mass spectroscopy, 1 H and 13 C NMR and X-ray crystallography. The crystal systems are monoclinic with space group P2 1 /n and four molecules per unit cell. These complexes shows 13 C NMR resonances of cationic counter ion [(py dc,H)] + in DMSO- d 6 but no signal corresponding to the two coordinated ligands [py dc] 2- The metal atoms are six-coordinated with a distorted octahedral geometry. The two [py de] 2- units are almost perpendicular to each other

Mechanism of pyridine-ligand exchanges at the different labile sites of 3d heterometallic and mixed valence mu3-oxo trinuclear clusters.

Science.gov (United States)

Novitchi, Ghenadie; Riblet, Fabrice; Scopelliti, Rosario; Helm, Lothar; Gulea, Aurelian; Merbach, André E

2008-11-17

The syntheses and single crystal X-ray structural analysis of five novel hetero- and homometallic mu 3-oxo trinuclear cluster with the formula [Fe (III) 2M (II)(mu 3-O)(mu-O 2CCH 3) 6(4-Rpy) 3]. x(4-Rpy). y(CH 3CN) where R = Ph for 1(Fe 2Mn), 2(Fe 2Fe), 3(Fe 2Co), 4(Fe 2Ni) and R = CF 3 for 5(Fe 2Co), are reported. The persistence of the structure for compounds 2- 5 in dichloromethane solution in the temperature range 190-320 K is demonstrated by (1)H and (19)F NMR spectroscopy. Even at the lowest temperature, the electron exchange in the homometallic mixed-valence compound 2(Fe 2Fe) is in the fast regime at the NMR time scale. Variable temperature and pressure NMR line broadening allowed quantifying the fast coordinated/free 4-Rpy exchanges at the two labile metal centers in these clusters: 2: Fe (III)( k (298)/10 (3) s (-1) = 16.6; Delta H (++) = 60.32 kJ mol (-1); Delta S (++) = + 34.8 J K (-1) mol (-1); Delta V (++) = + 12.5 cm (3) mol (-1)); 3: Fe (11.9; 58.92; +30.7; +10.6) and Co (2.8; 68.24; +49.8; +13.9); 4: Fe(12.2; 67.91; +61.0; -) and Ni (0.37; 78.62; +67.8; +12.3); 5: Fe (46; 58.21; +39.3; +14.2) and Co (4.7; 55.37; +11.2; +10.9). A limiting D mechanism is assigned to these exchange reactions. This assignment is based on a first-order rate law, the detection of intermediates, the positive and large entropies and volumes of activation. The order of reactivity k (Co) > k (Ni) is expected for a D mechanism at these metal centers: their low exchange rates are due to their strong binding with the 4-Rpy donor. Surrounded by oxygen donors the d (5) iron(III) usually reacts associatively; however, here due to low affinity of this ion for nitrogen the mechanism is D and the rate of exchange is very fast, even faster than on the divalent ions. There is no significant effect of the divalent ion in cluster 2, 3, and 5 on the exchange rates of 4-Phpy at the iron center, which seems to indicate that the specific electronic interactions between the three ions making

Design, characterization and evaluation of hydroxyethylcellulose based novel regenerable supersorbent for heavy metal ions uptake and competitive adsorption.

Science.gov (United States)

Abbas, Azhar; Hussain, Muhammad Ajaz; Sher, Muhammad; Irfan, Muhammad Imran; Tahir, Muhammad Nawaz; Tremel, Wolfgang; Hussain, Syed Zajif; Hussain, Irshad

2017-09-01

Hydroxyethylcellulose succinate-Na (HEC-Suc-Na) was designed and evaluated for removal of some heavy metal ions from aqueous solution. Pristine sorbent HEC-Suc-Na was thoroughly characterized by FTIR and solid-state CP/MAS 13 C NMR spectroscopy, SEM-EDS and zero point charge analyses. Langmuir isotherm, pseudo second order kinetic and ion exchange models provided best fit to the experimental data of sorption of metal ions. Maximum sorption capacities of supersorbent HEC-Suc-Na for sorption of heavy metal ions from aqueous solution as calculated by Langmuir isotherm model were found to be 1000, 909.09, 666.6, 588 and 500mgg -1 for Pb(II), Cr(VI), Co(II), Cu(II) and Ni(II), respectively. Competitive sorption of these heavy metal ions was carried out from galvanic and nuclear waste water simulated environment. The negative values of ΔG° and ΔH° indicated spontaneity and exothermic nature of sorption. The sorbent was efficiently regenerated with no significant decrease in sorption capacity after five cycles. Copyright © 2017 Elsevier B.V. All rights reserved.

Atmospheric pressure solid analysis probe coupled to quadrupole-time of flight mass spectrometry as a tool for screening and semi-quantitative approach of polycyclic aromatic hydrocarbons, nitro-polycyclic aromatic hydrocarbons and oxo-polycyclic aromatic hydrocarbons in complex matrices.

Science.gov (United States)

Carrizo, Daniel; Domeño, Celia; Nerín, Isabel; Alfaro, Pilar; Nerín, Cristina

2015-01-01

A new screening and semi-quantitative approach has been developed for direct analysis of polycyclic aromatic hydrocarbons (PAHs) and their nitro and oxo derivatives in environmental and biological matrices using atmospheric pressure solid analysis probe (ASAP) quadrupole-time of flight mass spectrometry (Q-TOF-MS). The instrumental parameters were optimized for the analysis of all these compounds, without previous sample treatment, in soil, motor oil, atmospheric particles (ashes) and biological samples such as urine and saliva of smokers and non-smokers. Ion source parameters in the MS were found to be the key parameters, with little variation within PAHs families. The optimized corona current was 4 µA, sample cone voltage 80 V for PAHs, nitro-PAHs and oxo-PAHs, while the desolvation temperatures varied from 300°C to 500°C. The analytical method performance was checked using a certified reference material. Two deuterated compounds were used as internal standards for semi-quantitative purposes together with the pure individual standard for each compound and the corresponding calibration plot. The compounds nitro PAH 9-nitroanthracene and oxo-PAH 1,4-naphthalenedione, were found in saliva and urine in a range below 1 µg/g while the range of PAHs in these samples was below 2 µg/g. Environmental samples provided higher concentration of all pollutants than urine and saliva. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis, characterization, antimicrobial and anthelmentic activities of some metal complexes with a new Schiff base 3-[(Z)-5-amino-1,3,3-trimethyl cyclohexylmethylimino]-1,3-dihydroindol-2-one

International Nuclear Information System (INIS)

Reddy, K. R. K; Mahendra, K.N.

2008-01-01

The complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), dioxouranium(VI), and Th(IV) with a new Schiff base, 3-[(Z)-5-amino-1,3,3-trimethyl cyclohexylmethylimino]-1,3-dihydroindol-2-one formed by the condensation of isatin (Indole-2.3-dione) with isophoronediamine(5-amino-1,3,3-trimethyl-cyclohexane methylamine) were synthesized and characterized by microanalysis, conductivity, UV-visible, FT-IR, 1 H NMR, TGA, and magnetic susceptibility measurements. All the complexes exhibit 1: 1 metal to ligand ratio except for the dioxouranium(VI) and thorium(IV) complexes, where the metal: ligand stoichiometry is 1: 2. The spectral data revealed that the ligand acts as monobasic bidentate, coordinating to the metal ion through the azomethine nitrogen and carbonyl oxygen of the isatin moiety. Tetrahedral geometry for Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) complexes, square planar geometry for Cu(II) complexes, and the coordination numbers 6 and 8 for UO 2 (VI) and Th(IV) complexes, respectively, are proposed. Both the ligand and the metal complexes were screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa, and the complexes are more potent bactericides than the ligand. The anthelmintic activity of the ligand and its complexes against earthworms was also investigated [ru

Adsorption of heavy metal ions from aqueous solutions by bio-char, a by-product of pyrolysis

International Nuclear Information System (INIS)

Kılıç, Murat; Kırbıyık, Çisem; Çepelioğullar, Özge; Pütün, Ayşe E.

2013-01-01

Bio-char, a by-product of almond shell pyrolysis, was used as an alternative adsorbent precursor for the removal of heavy metal ions from aqueous solutions. The adsorption potential of almond shell bio-char for Ni(II) and Co(II) removal was investigated. Adsorption experiments were carried out by varying pH, adsorbent dosage, initial metal ion concentrations, contact time and temperature to determine the optimum conditions. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin–Radushkevich (D–R) and Temkin isotherm models. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The results showed that bio-char derived from pyrolysis of biomass can be used as a low-cost and effective adsorbent for removal of heavy metal ions from aqueous solutions.

Gas-phase fragmentation of coordination compounds: loss of CO(2) from inorganic carbonato complexes to give metal oxide ions

Science.gov (United States)

Dalgaard; McKenzie

1999-10-01

Using electrospray ionization mass spectrometry, novel transition metal oxide coordination complex ions are proposed as the products of the collision-induced dissociation (CID) of some carbonato complex ions through the loss of a mass equivalent to CO(2). CID spectra of [(tpa)CoCO(3)](+) (tpa = tris(2-pyridylmethyl)methylamine), [(bispicMe(2)en)Fe(&mgr;-O)(&mgr;-CO(3))Fe(bispicMe(2)en)]2+ (bispicMe(2)en = N,N'-dimethyl-N,N'-bis(2-pyridylmethy)eth- ane-1, 2-diamine) and [(bpbp)Cu(2)CO(3)](+) (bpbp(-) = bis[(bis-(2-pyridylmethyl)amino)methyl]-4-tertbutylpheno-lato(1-)), show peaks assigned to the mono- and dinuclear oxide cations, [(tpa)CoO](+), [(bispicMe(2)en)(2)Fe(2)(O)(2)]2+ and [(bpbp)Cu(2)O](+), as the dominant species. These results can be likened to the reverse of typical synthetic reactions in which metal hydroxide compounds react with CO(2) to give metal carbonato compounds. Because of the lack of available protons in the gas phase, novel oxide species rather than the more common hydroxide ions are generated. These oxide ions are relevant to the highly oxidizing species proposed in oxygenation reactions catalysed by metal oxides and metalloenzymes. Copyright 1999 John Wiley & Sons, Ltd.

Co2+ ion exchange with NaY

International Nuclear Information System (INIS)

Garcia, I.; Solache-Rios, M.; Bulbulian, S.; Bosch, P.

1993-01-01

Co 2+ ion exchange from aqueous cobalt chloride-sodium chloride solutions with NaY zeolite has been investigated. The effect of contact time on the sorption of Co 2+ by dehydrated Y zeolite at 150 degrees C is unusual. A fast sorption uptake is observed in which 1.73 mequiv/g of zeolite of Na + ions is replaced by cobalt ions, followed by a desorption process where the uptake decreases to 1.56 mequiv/g of zeolite. This behavior is explained by the location and coordination of cobalt in Y zeolite sites. It is suggested that the maximum uptake corresponds to cobalt ions being simultaneously in two sites; tetrahedrally coordinated in the sodalite units and octahedrally coordinated in the large cavities. It is also suggested that the desorption process is a consequence of a reaction between Cl - ions and the tetrahedral species. 20 refs., 4 figs

The activity state of the branched-chain 2-oxo acid dehydrogenase complex in rat tissues.

Science.gov (United States)

Wagenmakers, A J; Schepens, J T; Veldhuizen, J A; Veerkamp, J H

1984-05-15

An assay is described to define the proportion of the branched-chain 2-oxo acid dehydrogenase complex that is present in the active state in rat tissues. Activities are measured in homogenates in two ways: actual activities, present in tissues, by blocking both the kinase and phosphatase of the enzyme complex during homogenization, preincubation, and incubation with 1-14C-labelled branched-chain 2-oxo acid, and total activities by blocking only the kinase during the 5 min preincubation (necessary for activation). The kinase is blocked by 5 mM-ADP and absence of Mg2+ and the phosphatase by the simultaneous presence of 50 mM-NaF. About 6% of the enzyme is active in skeletal muscle of fed rats, 7% in heart, 20% in diaphragm, 47% in kidney, 60% in brain and 98% in liver. An entirely different assay, which measures activities in crude tissue extracts before and after treatment with a broad-specificity protein phosphatase, gave similar results for heart, liver and kidney. Advantages of our assay with homogenates are the presence of intact mitochondria, the simplicity, the short duration and the high sensitivity. The actual activities measured indicate that the degradation of branched-chain 2-oxo acids predominantly occurs in liver and kidney and is limited in skeletal muscle in the fed state.

SBA-15-functionalized 3-oxo-ABNO as recyclable catalyst for aerobic oxidation of alcohols under metal-free conditions.

Science.gov (United States)

Karimi, Babak; Farhangi, Elham; Vali, Hojatollah; Vahdati, Saleh

2014-09-01

The nitroxyl radical 3-oxo-9-azabicyclo [3.3.1]nonane-N-oxyl (3-oxo-ABNO) has been prepared using a simple protocol. This organocatalyst is found to be an efficient catalyst for the aerobic oxidation of a wide variety of alcohols under metal-free conditions. In addition, the preparation and characterization of a supported version of 3-oxo-ABNO on ordered mesoporous silica SBA-15 (SABNO) is described for the first time. The catalyst has been characterized using several techniques including simultaneous thermal analysis (STA), transmission electron microscopy (TEM), and nitrogen sorption analysis. This catalyst exhibits catalytic performance comparable to its homogeneous analogue and much superior catalytic activity in comparison with (2,2,6,6-tetramethylpiperidin-1-yl)oxy (TEMPO) for the aerobic oxidation of almost the same range of alcohols under identical reaction conditions. It is also found that SABNO can be conveniently recovered and reused at least 12 times without significant effect on its catalytic efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Derivatives of 16alpha-hydroxy-dehydroepiandrosterone with an additional 7-oxo or 7-hydroxy substituent: synthesis and gas chromatography/mass spectrometry analysis.

Science.gov (United States)

Pouzar, Vladimír; Cerný, Ivan; Hill, Martin; Bicíková, Marie; Hampl, Richard

2005-10-01

Derivatives of 16alpha-hydroxy-dehydroepiandrosterone, which have an additional oxygen substituent at position 7 (oxo or hydroxy group), were synthesized. Firstly, 17,17-dimethoxyandrost-5-ene-3beta,16alpha-diyl diacetate was prepared and then oxidized with a complex of chromium(VI) oxide and 2,5-dimethylpyrazole to the respective 7-oxo derivative. This key intermediate was both deprotected or reduced by l-Selectride or sodium borohydride in the presence of cerium(III) chloride and then deprotected to give 7-oxo, 7alpha-hydroxy and 7beta-hydroxy derivatives of 16alpha-hydroxy-dehydroepiandrosterone. The target compounds were characterized by (1)H and (13)C NMR spectra and in the form of O-methyloxime-trimethylsilyl derivatives, by gas chromatography/mass spectrometry methods.

Ultraviolet spectroscopy and metal ions detection

International Nuclear Information System (INIS)

Chaudry, M.A.

1995-01-01

The spectrochemical analysis is based on the interaction of radiation with the chemical species and depends on their nature, having pi, sigma or electrons, or d and f electrons, UV. Visible spectrophotometry has been used extensively in the detection and determination of both organics and inorganics. In UV detection the sensitivity is proportional to the bath length and the excitation coefficient of the given sample. It may be insensitive to many species unless these are converted to UV, absorbing derivatives. The technique has been applied for the monitoring of the effluents from HPLC, as chlorides or other complexes of various elements in this article the utility of HCl as reagent for the spectrophotometric determination of the metal ions like Al(III), As(III,IV), Ba(II), Cd(II), Ca(II) Ce(III), Cs(i), Cr(III,VI), Co(II), Cu(II), Dy(III), Eu(III), Gd(III), Au(III), Hf(IV), Ho(III), In(III), Fe(III), La(III), Pb(II), Lu (III), Mg(II), Mn(II), Hg(II), Mo(VI), Ni(II), Pd(II), Pt(IV), K(I), Pr(III), Re(VII), Ru(IV), Sm(III), Sc(III), Ag(I), Sr(II) Te(III), Th(IV), Sn(II,IV), Ti(III,IV), W(VI), U(VI), V(IV,V), Yb(III), Zn(II) AND Zr(IV) Ions i.e. for meta ions from d of the most of these metal ions has been found sufficient permit their detection in HPLC. Their molar absorptive have also been reported. Reference has also been provided to post column derivatization of some metal ions from d and f block elements for their detection in HPLC. (author) 12 figs.; 6 tabs.; 27 refs

Two New Three-Dimensional Pillared-Layer Co(II and Cu(II Frameworks Involving a [M2(EO-N32] Motif from a Semi-Flexible N-Donor Ligand, 5,5′-Bipyrimidin: Syntheses, Structures and Magnetic Properties

Directory of Open Access Journals (Sweden)

Zu-Zhen Zhang

2018-02-01

Full Text Available Two new three-dimensional (3D Co(II- and Cu(II-azido frameworks, [Co2(N34(bpym2]n (1 and [Cu2(N34(bpym]n (2, were successfully synthesized by introducing a semi-flexible N-donor ligand, 5,5′-bipyrimidin (bpym, with different bridging modes and orientations. Compounds 1 and 2 were structurally characterized by X-ray crystallography, IR spectroscopy, thermogravimetry and elemental analysis. Compounds 1 and 2 are 3D pillared-layer frameworks with double end-on (EO azido bridged dinuclear motifs, [M2(EO-N32]. In Compound 1, the bpym ligands show trans μ2-bridging mode and the role as pillars to connect the Co(II-azido layers, composed of [Co2(EO-N32] motifs and single end-to-end (EE azido bridges, to a 3D network with BN topology. In contrast, in 2, the bpym ligand adopts a twisted μ4-bridging mode, which not only connects the adjacent [Cu2(EO-N32] units to a layer, but also functions as a pillar for the layers of the 3D structure. The structural diversities between the two types of architectures can be attributed to the coordination geometry preference of the metal ions (octahedral for Co2+ and square pyramidal for Cu2+. Magnetic investigations revealed that Compound 1 exhibits ferromagnetic-like magnetic ordering due to spin canting with a critical temperature, TC = 33.0 K, and furthers the field-induced magnetic transitions of metamagnetism at temperatures below TC. Compound 2 shows an antiferromagnetic ordering with TN = 3.05 K and a field-induced magnetic transition of spin-flop at temperatures below the TN.

Causes and consequences of plant radio-resistance. Formation of DNA basis lesions and self-repairing activity of one of them, the 8-oxo-7,8-dihydro-guanine in Arabidopsis thaliana

International Nuclear Information System (INIS)

Dany, A.L.

2001-01-01

In this research thesis, the author first explains how and why DNA is injured when it is submitted to an oxidizing stress, and describes precisely the formation and the biological consequences of lesions of DNA bases, the 8-oxo-7,8-dihydro-guanine (8-oxoGua). She describes the repairing activities of the oxidized DNA, and more particularly the repairing of 8-oxoGua, in prokaryotes as well as in yeast, mammals and plants. Methodologies used are described, together with the repair activities of the 8-oxo-7,8-dihydro-guanine following a biochemical type approach and a molecular biology approach

Synthesis and Microbiological Activity of Some Newly Synthesized Derivatives of 2-Oxo-2H-chromen-2-one

OpenAIRE

Daci-Ajvazi, Majlinda; Govori, Sevdije; Omeragiq, Shuhreta

2011-01-01

By the action of 2-amino-5-methylthio-1,3,4-thiadiazole, 3-amino-5-methylisoxazole, 2-amino-6-fluorobenzothiazole, 2-amino-5-chloropyridine, respectively, on 4-chloro-2-oxo-2H-chromene-3-sulfonyl chloride, the corresponding 9-methylthio-7,7-dioxo-7,7a-dihydro-5-oxo-7λ6,10-dithia-8,11-diaza-cyclopenta[b] phenantren-6-one, 9-methyl-7,7-dioxo-7H-5,8-dioxa-7λ6-thia-7a,11-diaza-cyclopenta[b] phenantren-6-one, 9-fluoro-7,7-dioxo-7H-5-oxa-7λ6,12-dithia-7a,13-diaza-indeno[1,2-b] phenantren-6-one and ...

Enantiopure Chiral Coordination Polymers Based on Polynuclear Paddlewheel Helices and Arsenyl Tartrate

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Ángela Valentín-Pérez

2018-03-01

Full Text Available Herein, we report the preparation of chiral, one-dimensional coordination polymers based on trinuclear paddlewheel helices [M3(dpa4]2+ (M = Co(II and Ni(II; dpa = the anion of 2,2′-dipyridylamine. Enantiomeric resolution of a racemic mixture of [M3(dpa4]2+ complexes was achieved by chiral recognition of the respective enantiomer by [Δ-As2(tartrate2]2− or [Λ-As2(tartrate2]2− in N,N-dimethylformamide (DMF, affording crystalline coordination polymers formed from [(Δ-Co3(dpa4(Λ-As2(tartrate2]·3DMF (Δ-1, [(Λ-Co3(dpa4(Δ-As2(tartrate2]·3DMF (Λ-1, [(Δ-Ni3(dpa4(Λ-As2(tartrate2]·(4 − nDMF∙nEt2O (Δ-2 or [(Λ-Ni3(dpa4(Δ-As2(tartrate2]·(4 − nDMF∙nEt2O (Λ-2 repeating units. UV-visible circular dichroism spectra of the complexes in DMF solutions demonstrate the efficient isolation of optically active species. The helicoidal [M3(dpa4]2+ units that were obtained display high stability towards racemization as shown by the absence of an evolution of the dichroic signals after several days at room temperature and only a small decrease of the signal after 3 h at 80 °C.

Microwave synthesis, spectral, thermal, and antimicrobial activities of some transition metal complexes involving 5-bromosalicylaldehyde moiety

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Rajendra K. Jain

2012-07-01

Full Text Available The coordination complexes of Co(II, Ni(II and Cu(II derived from 5-bromosalicylidene-3,4-dimethylaniline (BSMA and 5-bromosalicylidene-3,4-dichloroaniline (BSCA have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, molar conductance, electronic spectra, 1H-NMR, FAB-mass, ESR, magnetic susceptibility, electrical conductivity and thermal analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand ratio with coordination number 4 or 6. IR data shows that the ligand coordinates with the metal ions in a bidentate manner through the phenolic oxygen and azomethine nitrogen. FAB-mass and thermal data show degradation pattern of the complexes. Solid state electrical conductivity studies reflect semiconducting nature of the complexes. The Schiff base and metal complexes show a good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans.

Rhenium(V) oxo complexes relevant to technetium renal imaging agents derived from mercaptoacetylglycylglycylaminobenzoic acid isomers. Structural and molecular mechanics studies

International Nuclear Information System (INIS)

Hansen, L.; Taylor, A. Jr; Marzilli, L.G.; Cini, R.

1992-01-01

The synthesis and characterization of three rhenium(V) oxo complexes derived from isomers of mercaptoacetylglycylglycylaminobenzoic acid (MAG 2 -ABAH 5 ) are reported. The isomers were synthesized from o-, m- and p-aminobenzoic acid and differed in the position of the terminal carboxyl group. The anions of 8-10, [ReO(MAG 2 -*ABAH)] - (* = para (8), meta (9), ortho (10)), contained the tetraanionic form of the ligands with the carboxyl group protonated. Compounds 8,9, and 10 were synthesized by exchange reactions of ReOCl 3 (Me 2 SO)(Ph 3 P) under moderate conditions and were isolated as [Ph 4 P] + , [Bu 4 N] + , and [Ph 4 P] + salts, respectively. The structures of 8 and 10 were determined by X-ray diffraction methods; except for the location of the carboxyl group, the structures are similar. The coordination geometry is pseudo square pyramidal, with nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The orientation of the carboxyl group in 10 is anti to the Re double-bond O group. Since the carboxyl groups are protonated in 8 and 10 and in other relevant structures from this class of radiopharmaceuticals including [Ph 4 As][TcO(MAG 3 H)] (MAG 3 H = tetraanionic form of mercaptoacetyltriglycine), the authors developed molecular mechanics parameters that allowed them to calculate the structures of 8, 10, and [TcO(MAG 3 H)] - . They then extended the calculations to all three isomeric complexes in their deprotonated forms and to [TcO(MAG 3 )] 2- in order to approximate their solution phase structures. They conclude that the [TcO(MAG 3 )] 2- species is conformationally flexible, and they have made an initial assessment of structures vs renal clearance

Synthesis, characterization and vibrational spectra analysis of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate

Science.gov (United States)

Kıbrız, İbrahim Evren; Sert, Yusuf; Saçmacı, Mustafa; Şahin, Ertan; Yıldırım, İsmail; Ucun, Fatih

2013-10-01

In the present study, the experimental and theoretical vibrational spectra of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate (AOX) were investigated. The experimental FT-IR (400-4000 cm-1) and Laser-Raman spectra (100-4000 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles and torsion angles) were calculated using ab initio Hartree Fock (HF), Density Functional Theory (B3LYP and B3PW91) methods with 6-311++G(d,p) basis set by Gaussian 03 program, for the first time. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. The hydrogen bonding geometry of the molecule was also simulated to evaluate the effect of intermolecular hydrogen bonding on the vibrational frequencies. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were found.

Synthesis and thermal characterization of new ternary chelates of piroxicam and tenoxicam with glycine and DL-phenylalanine and some transition metals

Science.gov (United States)

Zayed, M. A.; El-Dien, F. A. Nour; Mohamed, Gehad G.; El-Gamel, Nadia E. A.

2006-05-01

The ternary chelates of piroxicam (Pir) and tenoxicam (Ten) with Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) in the presence of various amino acids such as glycine (Gly) or DL-phenylalanine (PhA) were prepared and characterized with different physicochemical methods. IR spectra confirm that Pir and Ten behave as a neutral bidentate ligand coordinated to the metal ions via the pyridine- N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its deprotonated carboxylic group. In addition, PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its deprotonated carboxylic and amino groups. The solid reflectance spectra and magnetic moment measurements confirm that all the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. Thermal behaviour of the complexes is extensively studied using TG and DTA techniques. TG results show that water molecules (hydrated and coordinated) and anions are removed in the first and second steps while Gly, PhA, Pir and Ten are decomposed in the next and subsequent steps. The pyrolyses of the chelates into different gases are observed in the DTA curves as exo- or endothermic peaks. Also, phase transition states are observed in some chelates. Different thermodynamic parameters are calculated using Coats-Redfern method and the results are interpreted.

Selective and Efficient Solvent Extraction of Copper(II Ions from Chloride Solutions by Oxime Extractants

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Zahra Kaboli Tanha

2016-06-01

Full Text Available Oxime extractants 3-tert-butyl-2-hydroxy-5-methyl benzaldehyde oxime (HL1 and 3-tert-butyl-2-hydroxy-5-methoxy benzaldehyde oxime (HL2 were synthesized and characterized by conventional spectroscopic methods. Suitable lipophilic nature of the prepared extractants allowed examining the ability of these molecules for extraction-separation of copper from its mixture with normally associated metal ions by performing competitive extraction experiments of Cu(II, Co(II, Ni(II, Zn(II, Cd(II and Pb(II ions from chloride solutions. Both ligands transfer selectively the copper ions into dichloromethane by a cation exchange mechanism. Conventional log-log analysis and isotherm curves showed that Cu(II ions are extracted as the complexes with 1:2 metal to ligand ratio by both extractants. Verification of the effect of the organic diluent used in the extraction of copper ions by HL1 and HL2 demonstrated that the extraction efficiency varies as: dichloromethane ~ dichloroethane > toluene > xylene > ethylacetate. Time dependency investigation of the extraction processes revealed that the kinetics of the extraction of copper by HL2 is more rapid than that of HL1. The application of the ligands for extraction-separation of copper ions from leach solutions of cobalt and nickel-cadmium filter-cakes of a zinc production plants was evaluated.

Hydrothermal synthesis, crystal structure and properties of a novel chain coordination polymer constructed by tetrafunctional phosphonate anions and cobalt ions

International Nuclear Information System (INIS)

Guan, Lei; Wang, Ying

2015-01-01

A novel cobalt phosphonate, [Co(HL)(H 2 O) 3 ] n (1) (L=N(CH 2 PO 3 H) 3 3− ) has been synthesized by hydrothermal reaction at 150 °C and structurally characterized by X-ray diffraction, infrared spectroscopy, elemental and thermogravimetric analysis. Complex 1 features a 1D chain structure with double-channel built from CoO 6 octahedra bridged together by the phosphonate groups. Each cobalt ion is octahedrally coordinated by three phosphonate oxygen atoms and three water molecules. The coordinated water molecules can form the hydrogen bonds with the phosphonate oxygen atoms to link the 1D chains, building a 2D layered structure, further resulting in a 3D network. The luminescence spectrum indicates an emission maximum at 435 nm. The magnetic susceptibility curve exhibits a dominant antiferromagnetic behavior with a weakly ferromagnetic component at low temperatures. - Graphical abstract: The connectivity between cobalt ions and the ligands results in a chain structure with a 1D double-channel structure, which is constructed by A-type subrings and B-type subrings. - Highlights: • The tetrafunctional phosphonate ligand was used as the ligand. • A novel chain structure can be formed by A-type rings and B-type rings. • Two types of rings can form a 1D double-channel structure, along the c-axis

Three-Dimensional Cadmium(II Cyanide Coordination Polymers with Ethoxy-, Butoxy- and Hexyloxy-ethanol

Directory of Open Access Journals (Sweden)

Takeshi Kawasaki

2016-08-01

Full Text Available The three novel cadmium(II cyanide coordination polymers with alkoxyethanols, [Cd(CN2(C2H5OCH2CH2OH]n (I, [{Cd(CN2(C4H9OCH2CH2OH}3{Cd(CN2}]n (II and [{Cd(CN2(H2O2}{Cd(CN2}3·2(C6H13OCH2CH2OH]n (III, were synthesized and charcterized by structural determination. Three complexes have three-dimensional Cd(CN2 frameworks; I has distorted tridymite-like structure, and, II and III have zeolite-like structures. The cavities of Cd(CN2 frameworks of the complexes are occupied by the alkoxyethanol molecules. In I and II, hydroxyl oxygen atoms of alkoxyethanol molecules coordinate to the Cd(II ions, and the Cd(II ions exhibit slightly distort trigonal-bipyramidal coordination geometry. In II, there is also tetrahedral Cd(II ion which is coordinated by only the four cyanides. The hydroxyl oxygen atoms of alkoxyethanol connects etheric oxygen atoms of the neighboring alkoxyethanol by hydrogen bond in I and II. In III, hexyloxyethanol molecules do not coordinate to the Cd(II ions, and two water molecules coordnate to the octahedral Cd(II ions. The framework in III contains octahedral Cd(II and tetrahedral Cd(II in a 1:3 ratio. The Cd(CN2 framework structures depended on the difference of alkyl chain for alkoxyethanol molecules.

Coligand-regulated assembly, fluorescence, and magnetic properties of Co(II) and Cd(II) complexes with a non-coplanar dicarboxylate

International Nuclear Information System (INIS)

Xin, Ling-Yun; Liu, Guang-Zhen; Ma, Lu-Fang; Wang, Li-Ya

2013-01-01

A non-coplanar dicarboxylate ndca (H 2 ndca=5-norbornene-2,3-dicarboxylic acid), combining with various dipyridyl-typed tectons, constructs six Cd(II)/Co(II) coordination polymers under hydrothermal conditions, namely [Co(ndca)(H 2 O)] n (1), ([Co(ndca)(bpe)(H 2 O)]·H 2 O) n (2), [Co(ndca)(bpa) 0.5 (H 2 O)] n (3), [Cd(ndca)(bpe)(H 2 O)] n (4), ([Cd(ndca)(bpa)(H 2 O)]·0.5H 2 O) n (5), and ([Cd(ndca)(bpp) (H 2 O)]·H 2 O) n (6) (bpe=1,2-di(4-pyridyl)ethylene, bpa=1,2-bi(4-pyridyl)ethane, and bpp=1,3-bis(4-pyridyl)propane). All these compounds contain various metal(II)–carboxylate motifs, including carboxylate binuclear (2, 4, 5), carboxylate chain (1, 6) and carboxylate layer (3), which are further extended by dipyridyl-typed coligands to afford a vast diversity of the structures with 2D pyknotic layers (1, 6), 2D open layer (5), 2D→3D interpenetrated networks (2,4), and 3D pillared-layer framework (3), respectively. In addition, fluorescent spectra of Cd(II) complexes and magnetic properties of Co(II) complexes are also given. - Graphical abstract: Six various cadmium(II)/cobalt(II)–organic frameworks were constructed by 5-norbornene-2,3-dicarboxylic acid and different bis(pyridine) rod-like tectons, and Cd (II) complexes exhibit blue–violet emissions, whereas Co (II) complexes show antiferromagnetic behaviours. Display Omitted

Retention data of bile acids and their oxo derivatives in characterization of pharmacokinetic properties and in silico ADME modeling.

Science.gov (United States)

Trifunović, Jovana; Borčić, Vladan; Vukmirović, Saša; Kon, Svetlana Goločorbin; Mikov, Momir

2016-09-20

Information on ADME properties of examined bile acids and their oxo derivatives are scarce, although the interest for bile acids and their use in nanochemistry and macromolecular chemistry is increasing. The purpose of this research was to evaluate the lipophilicity, a crucial physicochemical parameter for describing ADME properties of selected bile acids and their oxo derivatives, and to compare two approaches: experimentally determined hydrophobicity parameters and calculated logP values. Commercially available bile acids - deoxycholic, chenodeoxycholic, hyodeoxycholic and ursodeoxycholic acid were used to synthesize oxo derivatives. Lipophilicity was evaluated in two solvent systems: toluene/ethanol and toluene/butanol. Retention parameters were acquired by normal-phase TLC. The correlations between calculated logP values obtained using five different software and experimentally determined hydrophobicity parameters (RM(0)(tol/eth), RM(0)(tol/but), b(tol/eth) and b(tol/but)) were examined. Correlation analysis confirmed significant dependence between experimental RM(0) values and software calculated parameters. Results suggest satisfactory intestinal absorption after oral administration for all of the examined compounds as well as low volumes of distribution, and high affinity for binding with plasma proteins. Penetration through blood-brain barrier and skin is not satisfactory. All of the examined compounds show high affinity for binding with G-protein coupled receptors and consequently inhibition of ionic channels. Results also suggest possible binding with nuclear receptors. Established lipophilicity testing model of studied compounds showed excellent predictive ability and might represent significant tool in development of relations between chromatographic behavior and ADME properties. Compounds 3α-hydroxy-7,12-dioxo-5β-cholanoic and 12α-hydroxy-3,7-dioxo-5β-cholanoic acid might be the most suitable candidates for further development studies (satisfactory

The thermodynamic of complex formation in system of the Fe(III)-Fe(II)-benzimidazole-water in the inflation of ion strength in the formation of co-ordination compounds in the 288 K

International Nuclear Information System (INIS)

Nazarova, Kh.D.; Rajabov, U.R.; Yusupov, Z.N.

2005-01-01

With the Method of Oxredmatrion with application of the Oxidation Function in the Temperature 288 K and ion strength 0.1; 0.25; 0.50 and 1.00 in the Water solution of Benzimidazole been obtained the Formation Constants of the Coordination and their dependence with ion strength

Position of coordination of the lithium ion determines the regioselectivity of demethylations of 3,4-dimethoxymorphinans with L-selectride.

Science.gov (United States)

Wu, Huifang; Thatcher, Linn N; Bernard, Denzil; Parrish, Damon A; Deschamps, Jeffrey R; Rice, Kenner C; MacKerell, Alexander D; Coop, Andrew

2005-06-23

[reaction: see text] L-Selectride is an efficient agent for the 3-O-demethylation of opioids and is known to cleave the least hindered methoxyl group in a molecule. The treatment of a 3,4-dimethoxymorphinan containing a 6-ketal with L-Selectride gave selective 4-O-demethylation, rather than cleavage of the less hindered 3-methoxyl. In contrast, a 3,4-dimethoxymorphinan lacking a 6-ketal gave selective 3-O-demethylation, suggesting that the regiochemistry of L-Selectride-mediated O-demethylation can be manipulated through altering the position of coordination of the lithium ion.

Target-Triggered Switching on and off the Luminescence of Lanthanide Coordination Polymer Nanoparticles for Selective and Sensitive Sensing of Copper Ions in Rat Brain.

Science.gov (United States)

Huang, Pengcheng; Wu, Fangying; Mao, Lanqun

2015-07-07

Copper ions (Cu(2+)) in the central nervous system play a crucial role in the physiological and pathological events, so simple, selective, and sensitive detection of cerebral Cu(2+) is of great importance. In this work, we report a facile yet effective fluorescent method for sensing of Cu(2+) in rat brain using one kind of lanthanide coordination polymer nanoparticle, adenosine monophosphate (AMP) and terbium ion (Tb(3+)), i.e., AMP-Tb, as the sensing platform. Initially, a cofactor ligand, 5-sulfosalicylic acid (SSA), as the sensitizer, was introduced into the nonluminescent AMP-Tb suspension, resulting in switching on the luminescence of AMP-Tb by the removal of coordinating water molecules and concomitant energy transfer from SSA to Tb(3+). The subsequent addition of Cu(2+) into the resulting SSA/AMP-Tb can strongly quench the fluorescence because the specific coordination interaction between SSA and Cu(2+) rendered energy transfer from SSA to Tb(3+) inefficient. The decrease ratio of the fluorescence intensities of SSA/AMP-Tb at 550 nm show a linear relationship for Cu(2+) within the concentration range from 1.5 to 24 μM with a detection limit of 300 nM. The method demonstrated here is highly selective and is free from the interference of metal ions, amino acids, and the biological species commonly existing in the brain such as dopamine, lactate, and glucose. Eventually, by combining the microdialysis technique, the present method has been successfully applied in the detection of cerebral Cu(2+) in rat brain with the basal dialysate level of 1.91 ± 0.40 μM (n = 3). This method is very promising to be used for investigating the physiological and pathological events that cerebral Cu(2+) participates in.

Three two-dimensional coordination polymers constructed from transition metals and 2,3-norbornanedicarboxylic acid: Hydrothermal synthesis, crystal structures and photocatalytic properties

Science.gov (United States)

Zhang, Jia; Wang, Chong-Chen

2017-02-01

Three novel coordination polymers based on transition metals like Co(II), Cu(II) and Mn(II), namely [Co2(bpy)2(nbda)2(H2O)2]·2H2O (denoted as BUC-1), [Cu2(bpy)2(nbda)2(H2O)2]·2H2O (BUC-2), [Mn2(bpy)2(nbda)2(H2O)2]·2H2O (BUC-3), (where bpy = 4,4‧-bipyridine, H2nbda = 2,3-norbornanedicarboxylic acid, BUC = Beijing University of Civil Engineering and Architecture), were synthesized under hydrothermal conditions, and characterized by CNH elemental analyses (EA), Fourier Transform infrared spectroscopy (FTIR), and single crystal X-ray diffraction (SCXRD). BUC 1-3 were isostructural and crystallized in the monoclinic space group C2/c, in which the corresponding metal atoms were linked by typical bidentate bpy ligands into two adjacent 1D [M1(bpy)]n2n+ and [M2(bpy)]n2n+ (M = Co(II), Cu(II), Mn(II)), further joined by versatile nbda2- ligands into 2D [M2(bpy)2(nbda)2]n sheets. Finally, three-dimensional supramolecular frameworks were constructed with the aid of the intermolecular hydrogen bonding interactions. BUC 1-3 exhibited different photocatalytic degradation ability to decompose methylene blue (MB) and methyl orange (MO) under UV light irradiation. Additionally, a possible photocatalytic mechanism HOMO-LUMO was proposed and discussed, which was further confirmed by radicals trapping experiments using isopropanol as radical scavenger.

Synthesis and characterization of templated ion exchange resins for the selective complexation of actinide ions. 1998 annual progress report

International Nuclear Information System (INIS)

Murray, G.M.; Uy, O.M.

1998-01-01

'The purpose of this research is to develop polymeric extractants for the selective complexation of uranyl ions (and subsequently other actinyl and actinide ions) from aqueous solutions (lakes, streams, waste tanks and body fluids). Selectivity for a specific actinide ion is obtained by providing polymers with cavities lined with complexing ligands so arranged as to match the charge, coordination number, coordination geometry, and size of the actinide metal ion. These cavity-containing polymers will be produced using a specific actinide ion (or surrogate) as a template around which monomeric complexing ligands will be polymerized. The polymers will provide useful sequestering agents for removing actinide ions from wastes and will form the basis for a variety of analytical techniques for actinide determinations.'

Metal selective co-ordinative self-assembly of π-donors

Indian Academy of Sciences (India)

Metal selective co-ordinative nanostructures were constructed by the supramolecular ... observed an anomalous binding of metal ion to the core sulphur groups causing redox changes in the TTF ... attention on metal-assisted co-ordinative self-assembly ..... M TTF-Py in 1:1 CHCl3: MeCN and (c) photographs showing visual.

Effects of polyamines on the DNA-reactive properties of dimeric mithramycin complexed with cobalt(II): implications for anticancer therapy.

Science.gov (United States)

Hou, Ming-Hon; Lu, Wen-Je; Huang, Chun-Yu; Fan, Ruey-Jane; Yuann, Jeu-Ming P

2009-06-09

Few studies have examined the effects of polyamines on the action of DNA-binding anticancer drugs. Here, a Co(II)-mediated dimeric mithramycin (Mith) complex, (Mith)(2)-Co(II), was shown to be resistant to polyamine competition toward the divalent metal ion when compared to the Fe(II)-mediated drug complexes. Surface plasmon resonance experiments demonstrated that polyamines interfered with the binding capacity and association rates of (Mith)(2)-Co(II) binding to DNA duplexes, while the dissociation rates were not affected. Although (Mith)(2)-Co(II) exhibited the highest oxidative activity under physiological conditions (pH 7.3 and 37 degrees C), polyamines (spermine in particular) inhibited the DNA cleavage activity of the (Mith)(2)-Co(II) in a concentration-dependent manner. Depletion of intracellular polyamines by methylglyoxal bis(guanylhydrazone) (MGBG) enhanced the sensitivity of A549 lung cancer cells to (Mith)(2)-Co(II), most likely due to the decreased intracellular effect of polyamines on the action of (Mith)(2)-Co(II). Our study suggests a novel method for enhancing the anticancer activity of DNA-binding metalloantibiotics through polyamine depletion.

Poly[[[[1-ethyl-6,8-difluoro-7-(3-methylpiperazin-1-yl-4-oxo-1,4-dihydroquinoline-3-carboxylato]cadmium]-μ-benzene-1,4-dicarboxylato] trihydrate

Directory of Open Access Journals (Sweden)

Xin-Ping Kang

2010-11-01

Full Text Available In the title layered coordination polymer, {[Cd(C17H18F2N3O3(C8H4O4]·3H2O}n, the CdII atom exhibits a very distorted CdO6 octahedral geometry defined by one O3,O4-bidentate 1-ethyl-6,8-difluoro-7-(3-methylpiperazin-1-yl-4-oxo-1,4-dihydroquinoline-3-carboxylate (lome ligand, one O,O′-bidentate benzene-1,4-dicarboxylate (bdc dianion and two O-monodentate bdc dianions. Both the bdc species in the asymmetric unit are completed by crystallographic inversion symmetry. The bridging bdc dianions link the cadmium nodes into a rectangular grid lying parallel to (01overline{1}. A network of N—H...O and O—H...O hydrogen bonds helps to establish the packing.

Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

International Nuclear Information System (INIS)

Giraudi, G.; Baggiani, C.; Giovannoli, C.; Marletto, C.; Vanni, A.

1999-01-01

A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Activation of a water molecule coordinated to manganese: four study cases

International Nuclear Information System (INIS)

Lassalle-Kaiser, B.

2008-10-01

The daunting energy consumption of western societies calls for the development of renewable energies. Among them, hydrogen stands as a major candidate. The cleanest way of producing hydrogen is water electro- or photolysis. This reaction is carried out in natural photosynthesis by a manganese-oxo cluster, the functioning of which remains unknown. Insight into this mechanism would greatly help the search for low-cost water splitting catalysts. Our contribution to this field is the understanding of the fundamental processes that govern the activation of water by manganese complexes. This manuscript describes our attempts to generate electrochemically mononuclear manganese(IV) complexes bearing a fully deprotonated water molecule (oxo ligand). We have studied four different cases, which reflect different possible coordination spheres capable of stabilizing such species. In the first chapter, we will give a brief overview of the present energetic challenges faced by western societies. In the second chapter, we will present general considerations about manganese chemistry and a description of the structure and functioning of the water oxidizing enzyme. We will also describe the basic requirements for the splitting of water and present the goals of our work. In the third chapter, we will present the synthesis of a new family of tetradentate ligands, together with the synthesis and full characterization of the corresponding nickel(II) complexes. The first results obtained with the manganese analogue will also be shown. Chapter four presents the formation and the full characterization of a mononuclear manganese(IV)-oxo complex, by electrochemical oxidation of a manganese(II)-aqua complex. We will present different pathways to generate this species and show which intermediates are involved in this 2 e - , 2 H + reaction. Chapter five describes the formation of a mononuclear manganese(IV) complex, by electrochemical oxidation of a manganese(III)-hydroxo complex. The

Catena-poly[[bis(1H-benzotriazole-kappaN3)cobalt(II)]-di-mu-tricyanomethanido-kappa2N:N'] and catena-poly[[bis(3,5-dimethyl-1H-pyrazole-kappaN2)manganese(II)]-di-mu-tricyanomethanido-kappa2N:N'].

Science.gov (United States)

Shao, Ze-Huai; Luo, Jun; Cai, Rui-Fang; Zhou, Xi-Geng; Weng, Lin-Hong; Chen, Zhen-Xia

2004-06-01

Two new one-dimensional coordination polymers, viz. the title compounds, [Co[C(CN)(3)](2)(C(6)H(5)N(3))(2)](n), (I), and [Mn[C(CN)(3)](2)(C(5)H(8)N(2))(2)](n), (II), have been synthesized and characterized by X-ray diffraction. Both complexes consist of linear chains with double 1,5-tricyanomethanide bridges between neighbouring divalent metal ions. The Co and Mn atoms are located on centres of inversion. In (I), the coordination environment of the Co(II) atom is that of an elongated octahedron. The Co(II) atom is coordinated in the equatorial plane by four nitrile N atoms of four bridging tricyanomethanide ions, with Co-N distances of 2.106 (2) and 2.110 (2) A, and in the apical positions by two N atoms from the benzotriazole ligands, with a Co-N distance of 2.149 (2) A. The [Co[C(CN)(3)](2)(C(6)H(5)N(3))(2)] units form infinite chains extending along the a axis. These chains are crosslinked via a hydrogen bond between the uncoordinated nitrile N atom of a tricyanomethanide anion and the H atom on the uncoordinated N atom of a benzotriazole ligand from an adjacent chain, thus forming a three-dimensional network structure. In (II), the Mn(II) atom also adopts a slightly distorted octahedral geometry, with four nitrile N atoms of tricyanomethanide ligands [Mn-N = 2.226 (2) and 2.227 (2) A] in equatorial positions and two N atoms of the monodentate 3,5-dimethylpyrazole ligands [Mn-N = 2.231 (2) A] in the axial sites. In (II), one-dimensional polymeric chains extending along the b axis are formed, with tricyanomethanide anions acting as bidentate bridging ligands. A hydrogen bond between the uncoordinated nitrile N atom of the tricyanomethanide ligand and the H atom on the uncoordinated N atom of a 3,5-dimethylpyrazole group from a neighbouring chain links the molecule into a two-dimensional layered structure.

Three luminescent d{sup 10} metal coordination polymers assembled from a semirigid V-shaped ligand with high selective detecting of Cu{sup 2+} ion and nitrobenzene

Energy Technology Data Exchange (ETDEWEB)

Wu, Wei-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Institute of Functional Materials, College of Chemistry and Pharmaceutical Engineering, Sichuan University of Science & Engineering, Zigong 643000 (China); Liu, Ping; Liang, Yu-Tong; Cui, Lin; Xi, Zheng-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wang, Yao-Yu, E-mail: wyaoyu@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China)

2015-08-15

Three 2D luminescent coordination polymers with helical frameworks, [ZnL{sub 2}]{sub n} (1) and ([ML{sub 2}]·(H{sub 2}O)){sub n} (M=Zn (2), Cd (3)) (HL=4-((2-methyl-1 H-imidazol-1-yl)methyl)benzoic acid), have been assembled under hydro(solvo)thermal conditions. Complex 1 is in chiral space group and displays a rare 2D→2D 2-fold parallel interpenetrated layer network with two types of chiral double helixes. Interestingly, the single crystal structure analyses indicate the coexistence of enantiomers la and 1b in one pot, while the bulk crystallization of 1 are racemic mixtures based on the CD measurement. 2 and 3 are isostructural, in the structure, there are two kinds of 2D chiral helical-layers which stack in an -ABAB- sequence leading to the overall structure are mesomer and achiral. All compounds display intense luminescence in solid state at room temperature with high chemical and thermal stability. More importantly, 1 has been successfully applied in the detection of Cu{sup 2+} ions in aqueous media and nitrobenzene and the probable detecting mechanism was also discussed. - Graphical abstract: Three luminescent d{sup 10} metal coordination polymers with helical-layer based on 4-((2-methyl-1H-imidazol-1-yl)methyl)benzoic acid have been obtained. Compound 1 shows high selective detecting for Cu{sup 2+} ion in aqueous and nitrobenzene. - Highlights: • Three coordination polymers with chiral helical-layer have been obtained. • 1 Can luminescent detect Cu{sup 2+} ion in aqueous media and nitrobenzene. • Racemic mixture or mesomer compounds can be obtained by controlling the reaction conditions.

Synthesis, Structure and Properties of Two Novel 2D Zinc(II) Coordination Polymers based on Fluconazole and Benzene Carboxylic Acid

Energy Technology Data Exchange (ETDEWEB)

Pan, Ganghong; Tang, Jingniu; Xu, Wenjia; Liang, Peng; Huang, Zhongjing [Guangxi University for Nationalities, Nanning (China)

2013-12-15

The design and synthesis of coordination polymers have aroused great interest owing to their intriguing aesthetic structures and potential applications in nonlinear optics, gas storage, ion exchange, luminescence, magnetism and catalysis. Self-assembly of bridging organic ligands (connectors) and multi-connected metal ions can give rise to various types of interesting coordination polymers. Since metal ion Zn(II) with d{sup 10} electronic configuration permits a variety of coordination numbers and geometries which are not dependent on ligand field stabilization but on ligand size and charge, it is well suited for the construction of various coordination polymers. Its borderline hardness allows the coordination of N, O and S donor atoms.

Removal of radiocobalt from aqueous solutions by kaolinite affected by solid content, pH, ionic strength, contact time and temperature

International Nuclear Information System (INIS)

Kan Li; Zhengjie Liu; Lei Chen; Yunhui Dong; Jun Hu; Chinese Academy of Sciences, Hefei

2013-01-01

The kaolinite sample was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction, and was applied as adsorbent for the removal of radiocobalt ions from radioactive wastewater. The results demonstrated that the sorption of Co(II) was strongly dependent on pH and ionic strength at low pH values, and independent of pH and ionic strength at high pH values. The sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange at low pH values, whereas inner-sphere surface complexation was the main sorption mechanism at high pH values. The sorption isotherms were well described by Langmuir, Freundlich and Dubinin-Radushkevich models. The thermodynamic parameters (i.e., ΔGdeg, ΔSdeg, ΔHdeg) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on kaolinite was an endothermic and spontaneous process. The results of high sorption capacity of kaolinite suggested that the kaolinite sample was a suitable material for the preconcentration of Co(II) from large volumes of aqueous solutions and as backfill materials in nuclear waste management. (author)

A symmetric, triply interlaced 3-D anionic MOF that exhibits both magnetic order and SMM behaviour.

Science.gov (United States)

Campo, J; Falvello, L R; Forcén-Vázquez, E; Sáenz de Pipaón, C; Palacio, F; Tomás, M

2016-11-14

A newly prepared 3-D polymer of cobalt citrate cubanes bridged by high-spin Co(ii) centres displays both single-molecule magnet (SMM) behaviour and magnetic ordering. Triple interpenetration of the 3-D diamondoid polymers yields a crystalline solid with channels that host cations and free water molecules, with the SMM behaviour of the Co 4 O 4 cores preserved. The octahedrally coordinated Co(ii) bridges are implicated in the onset of magnetic order at an experimentally accessible temperature.

Synthesis of thiadiazolobenzamide via cyclization of thioxothiourea and its Ni and Pd complexes

Directory of Open Access Journals (Sweden)

Adhami Forogh

2012-01-01

Full Text Available In this study, the new compound, N-(3-methyl-4- oxo[1,3,4]thiadiazolo[2,3-c][1,2,4]triazin-7-yl benzamide, could be obtained via two different reactions: 1 reaction of 4-amino-6-Methyl-3- (Methylsulfanyl-1,2,4-triazin-5-one with benzoyl isothiocyanate under removal of methylmercaptane, 2 reaction of 4-amino-6-Methyl-3-thioxo- 1,2,4-triazin-5-one with benzoyl isothiocyanate under elimination of hydrogen sulfide. In both reactions a new bond between sulfur and nitrogen atoms was formed and a five-membered ring was created. The oxo thiadiazolo benzamide was characterized by IR-, 1HNMR- and 13CNMR spectroscopy as well as by Mass spectrometry. X-ray crystallography was used to shed light on the structure of this new compound. Two new complexes could be generated by coordination of oxo thiadiazolo benzamide to Pd(II and Ni(II ions. These complexes have been analyzed by IR-, 1HNMR- and 13CNMR spectroscopy, conductometry and Thermal gravimetry (TGA. Theoretical QM Calculation GIAO has also been applied to predict the structure of the Pd complex.

Structural and thermal characterization of ternary complexes of piroxicam and alanine with transition metals: Uranyl binary and ternary complexes of piroxicam. Spectroscopic characterization and properties of metal complexes

Science.gov (United States)

Mohamed, Gehad G.

2005-12-01

Ternary Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO 2(II) complexes with piroxicam (Pir) drug (H 2L 1) and dl-alanine (Ala) (HL 2) and also the binary UO 2(II) complex with Pir were studied. The structures of the complexes were elucidated using elemental, IR, molar conductance, magnetic moment, diffused reflectance and thermal analyses. The UO 2(II) binary complex was isolated in 1:2 ratio with the formula [UO 2(H 2L) 2](NO 3) 2. The ternary complexes were isolated in 1:1:1 (M:H 2L 1:L 2) ratios. The solid complexes were isolated in the general formulae [M(H 2L)(L 2)(Cl) n(H 2O) m]· yH 2O (M = Fe(III) ( n = 2, m = 0, y = 1), Co(II) ( n = 1, m = 1, y = 2) and Ni(II) ( n = 1, m = 1, y = 0)); [M(H 2L)(L 2)](X) z· yH 2O (M = Cu(II) (X = AcO, z = 1, y = 0), Zn(II) (X = AcO, z = 1, y = 3) and UO 2(II) (X = NO 3, z = 1, y = 2)). Pir behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl-O groups, while Ala behaves as a uninegatively bidentate ligand coordinated to the metal ions via the deprotonated carboxylate-O and amino-N. The magnetic and reflectance spectral data show that the complexes have octahedral geometry except Cu(II) and Zn(II) complexes have tetrahedral structures. The thermal decomposition of the complexes was discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated.

Estudio de la biodegradación de bolsas oxo - biodegradables en agua dulce y salada, simulando condiciones ambientales de Costa, Sierra y Oriente Ecuatoriano.

OpenAIRE

Escobar Silva, Nelly Jacqueline

2014-01-01

This work allowed the study of biodegradation of four types of oxo-biodegradable bags by environmental conditions simulated in fresh and salt water of the Costa, Sierra and Oriente regions. El presente trabajo permitió el estudio de la biodegradación de cuatro tipos de bolsas oxo-biodegradables mediante condiciones ambientales simuladas en el agua dulce y salada de las regiones Costa, Sierra y Oriente ecuatoriano.

Hypersensitive transition spectrum of f-element and coordination structure

International Nuclear Information System (INIS)

Cao Xuan; Song Chongli; Zhu Youngjun

1992-10-01

Some f-f transitions of Ln(An) metallic ions have particular super-sensitivity to the change of coordination environments. This is called super-sensitive transitions. Based on the irreducible tensor operator method, a computation model and corresponding computer program for calculating the hypersensitive transition spectrum of f-element were developed. By comparing the theoretical spectra of all possible coordination structures with experimental one, the possible coordination structures of complex can be determined. The coordination structures of Nd 3+ , Er 3 + hydrate and their extraction complex with H(DEHP) were successfully determined by this method, and the experimental spectra were also assigned

Lanthanum(III) and Lutetium(III) in Nitrate-Based Ionic Liquids: A Theoretical Study of Their Coordination Shell.

Science.gov (United States)

Bodo, Enrico

2015-09-03

By using ab initio molecular dynamics, we investigate the solvent shell structure of La(3+) and Lu(3+) ions immersed in two ionic liquids, ethylammonium nitrate (EAN) and its hydroxy derivative (2-ethanolammonium nitrate, HOEAN). We provide the first study of the coordination properties of these heavy metal ions in such a highly charged nonacqueous environment. We find, as expected, that the coordination in the liquid is mainly due to nitrate anions and that, due to the bidentate nature of the ligand, the complexation shell of the central ion has a nontrivial geometry and a coordination number in terms of nitrate molecules that apparently violates the decrease of ionic radii along the lanthanides series, since the smaller Lu(3+) ion seems to coordinate six nitrate molecules and the La(3+) ion only five. A closer inspection of the structural features obtained from our calculations shows, instead, that the first shell of oxygen atoms is more compact for Lu(3+) than for La(3+) and that the former coordinates 8 oxygen atoms while the latter 10 in accord with the typical lanthanide's trend along the series and that their first solvation shells have a slight irregular and complex geometrical pattern. When moving to the HOEAN solutions, we have found that the solvation of the central ion is possibly also due to the cation itself through the oxygen atom on the side chain. Also, in this liquid, the coordination numbers in terms of oxygen atoms in both solvents is 10 for La(3+) and 8 for Lu(3+).

Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst

KAUST Repository

Merle, Nicolas; Le Qué mé ner, Fré dé ric; Bouhoute, Yassine; Szeto, Kai C.; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja; Delevoye, Laurent; Gauvin, Ré gis M.; Taoufik, Mostafa; Basset, Jean-Marie

2016-01-01

The well-defined silica-supported molybdenum oxo alkyl species (SiO−)MoO(CH Bu) was selectively prepared by grafting of MoO(CH Bu)Cl onto partially dehydroxylated silica (silica) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO/SiO olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst

KAUST Repository

Merle, Nicolas

2016-12-05

The well-defined silica-supported molybdenum oxo alkyl species (SiO−)MoO(CH Bu) was selectively prepared by grafting of MoO(CH Bu)Cl onto partially dehydroxylated silica (silica) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO/SiO olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

New chemistry of the uranyl ion in non aqueous media

International Nuclear Information System (INIS)

Siffredi, G.

2008-12-01

This work deals with new aspects of the chemistry of the uranyl(VI) ion {UO 2 } 2+ in anhydrous polar organic solvents such as the activation of the reputedly inert U-O yl bond and the controlled reduction of this species which represent a particularly active field of research that attracts much attention for both its fundamental aspects and applications. Treatment of uranyl(VI) compounds UO 2 X' 2 (X' = I, OTf, Cl) with Me 3 SiX (X = Cl, Br, I) reagents, in various anhydrous polar organic solvents, has been first considered. In most cases, reduction into tetravalent species with complete de-oxygenation of the uranyl {UO 2 } 2+ ion is observed. The reaction is particularly efficient in acetonitrile where the tetravalent [UX 4 (MeCN) 4 ] complexes, which are useful precursors in uranium chemistry, are isolated. In the course of these reactions, the influence of the solvent, the nature of X' and X in the UO 2 X' 2 precursor and the Me 3 SiX reagent are pointed out. Reaction of the uranyl(VI) UO 2 X 2 (X = I, Cl, OTf, NO 3 ) precursors with the anionic MC 5 R 5 (M = K, R = H, Me; M= Li, R = Me; M= Tl, R = H) reagents did not lead to the organometallic [(η 5 -C 5 R 5 ) n UO 2 X 2-n ] species (n = 1, 2) but to pentavalent uranyl(V) complexes. This method is a facile and rapid route towards the formation of stable pentavalent uranyl which offers promising sources for further U(V) chemical developments and for fundamental and applied interests. Their structure is strongly dependent on the nature of the solvent, the additional ligands X and of the M + cation. In pyridine, the {UO 2 (py) 5 } + ion appears to be an ubiquitous and a quite stable entity. The coordinating properties of the basic oxo groups, which coordinate easily to M + ions (M= Li, K, Tl), favour structural diversity with formation of hetero-polymetallic complexes such as [{UO 2 (py) 5 }{MX(py) 2 }] (M= Li, X I), [{UO 2 (py) 5 }{MX 2 (py) 2 }] ∞ (M= K, Tl, X= OTf; M= K, X= I), [{UO 2 (py) 5 }(M 2 X 3 )]�

Coligand-regulated assembly, fluorescence, and magnetic properties of Co(II) and Cd(II) complexes with a non-coplanar dicarboxylate

Energy Technology Data Exchange (ETDEWEB)

Xin, Ling-Yun [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Liu, Guang-Zhen, E-mail: gzliuly@126.com [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Ma, Lu-Fang [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Wang, Li-Ya [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang 473061 (China)

2013-10-15

A non-coplanar dicarboxylate ndca (H{sub 2}ndca=5-norbornene-2,3-dicarboxylic acid), combining with various dipyridyl-typed tectons, constructs six Cd(II)/Co(II) coordination polymers under hydrothermal conditions, namely [Co(ndca)(H{sub 2}O)]{sub n} (1), ([Co(ndca)(bpe)(H{sub 2}O)]·H{sub 2}O){sub n} (2), [Co(ndca)(bpa){sub 0.5}(H{sub 2}O)]{sub n} (3), [Cd(ndca)(bpe)(H{sub 2}O)]{sub n} (4), ([Cd(ndca)(bpa)(H{sub 2}O)]·0.5H{sub 2}O){sub n} (5), and ([Cd(ndca)(bpp) (H{sub 2}O)]·H{sub 2}O){sub n} (6) (bpe=1,2-di(4-pyridyl)ethylene, bpa=1,2-bi(4-pyridyl)ethane, and bpp=1,3-bis(4-pyridyl)propane). All these compounds contain various metal(II)–carboxylate motifs, including carboxylate binuclear (2, 4, 5), carboxylate chain (1, 6) and carboxylate layer (3), which are further extended by dipyridyl-typed coligands to afford a vast diversity of the structures with 2D pyknotic layers (1, 6), 2D open layer (5), 2D→3D interpenetrated networks (2,4), and 3D pillared-layer framework (3), respectively. In addition, fluorescent spectra of Cd(II) complexes and magnetic properties of Co(II) complexes are also given. - Graphical abstract: Six various cadmium(II)/cobalt(II)–organic frameworks were constructed by 5-norbornene-2,3-dicarboxylic acid and different bis(pyridine) rod-like tectons, and Cd (II) complexes exhibit blue–violet emissions, whereas Co (II) complexes show antiferromagnetic behaviours. Display Omitted.

Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid for the determination of metal ions by capillary electrophoresis.

Science.gov (United States)

Krokhin, O V; Kuzina, O V; Hoshino, H; Shpigun, O A; Yotsuyanagi, T

2000-08-25

Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxyphenylacetic acid) (EDDHA) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), were applied for the separation of transition and heavy metal ions by the ion-exchange variant of electrokinetic chromatography. EDDHA structure contains two chiral carbon centers. It makes it impossible to use the commercially available ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separation of metal-HBED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate-hydroxide form. Simultaneous separation of nine single- and nine double-charged HBED chelates, including In(III), Ga(III), Co(II)-(III) and Mn(II)-(III) pairs demonstrated the efficiency of 40,000-400,000 theoretical plates. The separation of Co(III), Fe(III) complexes with different arrangements of donor groups and oxidation of Co(II), Mn(H), Fe(II) ions in reaction with HBED have been discussed.

Formation of Conjugated Double Bonds to Induce Polystyrene Conductivity by using Different Concentrations of Methoxo-Oxo Bis (8-Quinolyloxo Vanadium (V

Directory of Open Access Journals (Sweden)

Basim Mohamad Hasan

2017-02-01

Full Text Available The effect of different concentrations of additive compound methoxo–oxo bis (8-quinolyloxo vanadium (v on formation of conjugated double bonds as part of photo transformation of polystyrene has been investigated. The UV-Vis spectrophotometery has been used in this work. The results are show that additive concentrations applied increase the formation of conjugated double bond as compared with polystyrene. In this study methoxo – oxo bis (8-quinolyloxo vanadium (v indicates great activity to enhance the conductivity of polystyrene by formation of conjugated double bonds.

Facile and green preparation of novel adsorption materials by combining sol-gel with ion imprinting technology for selective removal of Cu(II) ions from aqueous solution

Science.gov (United States)

Ren, Zhongqi; Zhu, Xinyan; Du, Jian; Kong, Delong; Wang, Nian; Wang, Zhuo; Wang, Qi; Liu, Wei; Li, Qunsheng; Zhou, Zhiyong

2018-03-01

A novel green adsorption polymer was prepared by ion imprinted technology in conjunction with sol-gel process under mild conditions for the selective removal of Cu(II) ions from aqueous solution. Effects of preparation conditions on adsorption performance of prepared polymers were studied. The ion-imprinted polymer was prepared using Cu(II) ion as template, N-[3-(2-aminoethylamino) propyl] trimethoxysilane (AAPTMS) as functional monomer and tetraethyl orthosilicate (TEOS) as cross-linker. Water was used as solvent in the whole preparation process. The imprinted and non-imprinted polymers were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM), Brunauer, Emmett and Teller (BET) and zeta potential. Three-dimensional network structure was formed and functional monomer was successfully cross-linked into the network structure of polymers. Effects of adsorption conditions on adsorption performance of prepared polymers were studied too. The pH value is of great influence on adsorption behavior. Adsorption by ion-imprinted polymer was fast (adsorption equilibrium was reached within 60 min). The adsorption capacity of Cu(II) ion-imprinted polymer was always larger than that of non-imprinted polymer. Pseudo-second-order kinetics model and Freundlich isotherm model fitted well with adsorption data. The maximum adsorption capacity of Cu(II) ion-imprinted polymer was 39.82 mg·g-1. However, the preparation conditions used in this work are much milder than those reported in literatures. The Cu(II) ion-imprinted polymer showed high selectivity and relative selectivity coefficients for Pb(II), Ni(II), Cd(II) and Co(II). In addition, the prepared ion-imprinted polymer could be reused several times without significant loss of adsorption capacity.

Synthesis, characterization and anticancer activity of kaempferol-zinc(II) complex.

Science.gov (United States)

Tu, Lv-Ying; Pi, Jiang; Jin, Hua; Cai, Ji-Ye; Deng, Sui-Ping

2016-06-01

According to the previous studies, the anticancer activity of flavonoids could be enhanced when they are coordinated with transition metal ions. In this work, kaempferol-zinc(II) complex (kaempferol-Zn) was synthesized and its chemical properties were characterized by UV-VIS, FT-IR, (1)H NMR, elemental analysis, electrospray mass spectrometry (ES-MS) and fluorescence spectroscopy, which showed that the synthesized complex was coordinated with a Zn(II) ion via the 3-OH and 4-oxo groups. The anticancer effects of kaempferol-Zn and free kaempferol on human oesophageal cancer cell line (EC9706) were compared. MTT results demonstrated that the killing effect of kaempferol-Zn was two times higher than that of free kaempferol. Atomic force microscopy (AFM) showed the morphological and ultrastructural changes of cellular membrane induced by kaempferol-Zn at subcellular or nanometer level. Moreover, flow cytometric analysis indicated that kaempferol-Zn could induce apoptosis in EC9706 cells by regulating intracellular calcium ions. Collectively, all the data showed that kaempferol-Zn might be served as a kind of potential anticancer agent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Revisiting and re-engineering the classical zinc finger peptide: consensus peptide-1 (CP-1).

Science.gov (United States)

Besold, Angelique N; Widger, Leland R; Namuswe, Frances; Michalek, Jamie L; Michel, Sarah L J; Goldberg, David P

2016-04-01

Zinc plays key structural and catalytic roles in biology. Structural zinc sites are often referred to as zinc finger (ZF) sites, and the classical ZF contains a Cys2His2 motif that is involved in coordinating Zn(II). An optimized Cys2His2 ZF, named consensus peptide 1 (CP-1), was identified more than 20 years ago using a limited set of sequenced proteins. We have reexamined the CP-1 sequence, using our current, much larger database of sequenced proteins that have been identified from high-throughput sequencing methods, and found the sequence to be largely unchanged. The CCHH ligand set of CP-1 was then altered to a CAHH motif to impart hydrolytic activity. This ligand set mimics the His2Cys ligand set of peptide deformylase (PDF), a hydrolytically active M(II)-centered (M = Zn or Fe) protein. The resultant peptide [CP-1(CAHH)] was evaluated for its ability to coordinate Zn(II) and Co(II) ions, adopt secondary structure, and promote hydrolysis. CP-1(CAHH) was found to coordinate Co(II) and Zn(II) and a pentacoordinate geometry for Co(II)-CP-1(CAHH) was implicated from UV-vis data. This suggests a His2Cys(H2O)2 environment at the metal center. The Zn(II)-bound CP-1(CAHH) was shown to adopt partial secondary structure by 1-D (1)H NMR spectroscopy. Both Zn(II)-CP-1(CAHH) and Co(II)-CP-1(CAHH) show good hydrolytic activity toward the test substrate 4-nitrophenyl acetate, exhibiting faster rates than most active synthetic Zn(II) complexes.

Transport of Alkali Metal Ions through a Liquid Membrane System ...

African Journals Online (AJOL)

crown-6, [K(MF18C6)](picrate) was determined by X-ray crystallography and showed that each potassium ion is eight-coordinate; each K+ ion is coordinated to the six oxygen atoms of the crown, to the phenolate oxygen atom and to one of the ...

Studies on chelation properties of ampicillin with trace metal ions and comparison with penicillin complexes

International Nuclear Information System (INIS)

Rehmani, F.S.; Hameed, W.

2003-01-01

The penicillin is highly effective antibiotic with extremely wide margin of safety. Ampicillin e is the penicillin group of antibiotic in which side chain is phenyl group i.e. D-amino benzyl penicillin. The side chain determines many of anti bacterial and pharmacological characteristics. They inhibit the protein synthesis in bacterial cell wall. The chelating properties of the antibiotic may be used in the metal transport across the membrane. The present investigations are helpful in drug metabolism and their effects on minerals contents of the body. The complex formation between Ampicillin and penicillin with trace metal ions such as Fe(III), Cr(III), Al(III), Mn(II), Ni(II), Co(II), Ca(II), Mg(II), Cu(III) and Zn(II) were studied by potentiometric titrations and spectrophotometric methods. Stoichiometry of these complexes were studied by mole ratio method. It was found that the Fe(III) and Cu(II) ions form most stable complexes near physiological pH and the mole ratio was 1:1. (author)

Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis

Energy Technology Data Exchange (ETDEWEB)

Yang, Yin; Huang, Feng [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China); Huber, Thomas [Australian National University, Research School of Chemistry (Australia); Su, Xun-Cheng, E-mail: xunchengsu@nankai.edu.cn [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China)

2016-02-15

Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i − 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data.

Adaptable coordination of U(IV) in the 2D-(4,4) uranium oxalate network: From 8 to 10 coordinations in the uranium (IV) oxalate hydrates

International Nuclear Information System (INIS)

Duvieubourg-Garela, L.; Vigier, N.; Abraham, F.; Grandjean, S.

2008-01-01

Crystals of uranium (IV) oxalate hydrates, U(C 2 O 4 ) 2 .6H 2 O (1) and U(C 2 O 4 ) 2 .2H 2 O (2), were obtained by hydrothermal methods using two different U(IV) precursors, U 3 O 8 oxide and nitric U(IV) solution in presence of hydrazine to avoid oxidation of U(IV) into uranyl ion. Growth of crystals of solvated monohydrated uranium (IV) oxalate, U(C 2 O 4 ) 2 .H 2 O.(dma) (3), dma=dimethylamine, was achieved by slow diffusion of U(IV) into a gel containing oxalate ions. The three structures are built on a bi-dimensional complex polymer of U(IV) atoms connected through bis-bidentate oxalate ions forming [U(C 2 O 4 )] 4 pseudo-squares. The flexibility of this supramolecular arrangement allows modifications of the coordination number of the U(IV) atom which, starting from 8 in 1 increases to 9 in 3 and, finally increases, to 10 in 2. The coordination polyhedron changes from a distorted cube, formed by eight oxygen atoms of four oxalate ions, in 1, to a mono-capped square anti-prism in 3 and, finally, to a di-capped square anti-prism in 2, resulting from rotation of the oxalate ions and addition of one and two water oxygen atoms in the coordination of U(IV). In 1, the space between the ∞ 2 [U(C 2 O 4 ) 2 ] planar layers is occupied by non-coordinated water molecules; in 2, the space between the staggered ∞ 2 [U(C 2 O 4 ) 2 .2H 2 O] layers is empty, finally in 3, the solvate molecules occupy the interlayer space between corrugated ∞ 2 [U(C 2 O 4 ) 2 .H 2 O] sheets. The thermal decomposition of U(C 2 O 4 ) 2 .6H 2 O under air and argon atmospheres gives U 3 O 8 and UO 2 , respectively. - Graphical abstract: The adaptable environment of U(IV) in U(IV) oxalates: from eight cubic coordination in U(C 2 O 4 ) 2 .6H 2 O (a) completed by water oxygens to nine in [U(C 2 O 4 ) 2 .H 2 O](C 2 NH 5 ) (b) and ten coordination in U(C 2 O 4 ) 2 .2H 2 O (c)

Health status of cows fed maize silage covered with oxo-biodegradable foil

OpenAIRE

Piotr SZTERK; Piotr DORSZEWSKI; Małgorzata GRABOWICZ; Lucyna PODKÓWKA

2017-01-01

In agricultural practice, silage production uses pure, low density polyethylene foil. This foil, after use, becomes farm waste, having a negative impact on the environment. Instead of conventional foil, an environmentally safe biodegradable foil can be used, made from naturally occurring polymers or from synthetic multiparticulates, easily degradable by microorganisms. Silage covered with this type of foil should be safe for animal health. The purpose of the study was to determine whether oxo...

5-Methyl-4-oxo-4,6-dihydro-3H-pyridazino[4,5-b]carbazole-1-carbonitrile

Directory of Open Access Journals (Sweden)

Norbert Haider

2010-02-01

Full Text Available The title compound was prepared in excellent yield from 5-methyl-4-oxo-4,6-dihydro-3H-pyridazino[4,5-b]carbazole-1-carbaldehyde by treatment with hydroxylamine hydrochloride in formic acid without isolation of the intermediate oxime.

Visualisation of abscisic acid and 12-oxo-phytodienoic acid in immature Phaseolus vulgaris L. seeds using desorption electrospray ionisation-imaging mass spectrometry

Science.gov (United States)

Enomoto, Hirofumi; Sensu, Takuya; Sato, Kei; Sato, Futoshi; Paxton, Thanai; Yumoto, Emi; Miyamoto, Koji; Asahina, Masashi; Yokota, Takao; Yamane, Hisakazu

2017-02-01

The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise ABA and OPDA in immature Phaseolus vulgaris L. seed sections. The mass spectra, peak values and chemical formulae obtained from the analysis of seed sections were consistent with those determined for ABA and OPDA standards, as were the precursor and major fragment ions observed in tandem mass spectrometry (MS/MS) imaging. Furthermore, the precursor and fragment ion images showed similar distribution patterns. In addition, the localisation of ABA and OPDA using DESI-IMS was confirmed using liquid chromatography-MS/MS (LC-MS/MS). The results indicated that ABA was mainly distributed in the radical and cotyledon of the embryo, whereas OPDA was distributed exclusively in external structures, such as the hilum and seed coat. The present study is the first to report the visualisation of plant hormones using IMS, and demonstrates that DESI-IMS is a promising technique for future plant hormone research.

Development of the first well-defined tungsten oxo alkyl derivatives supported on silica by SOMC: towards a model of WO3/SiO2 olefin metathesis catalyst

KAUST Repository

Mazoyer, Etienne; Merle, Nicolas; Mallmann, Aimery De; Basset, Jean-Marie; Berrier, Elise; Delevoye, Laurent; Paul, Jean Franois; Nicholas, Christopher P.; Gauvin, Ré gis M.; Taoufik, Mostafa

2010-01-01

A well-defined, silica-supported tungsten oxo alkyl species prepared by the surface organometallic chemistry approach displays high and sustained activity in propene metathesis. Remarkably, its catalytic performances outpace those of the parent imido derivative, underlining the importance of the oxo ligand in the design of robust catalysts. © 2010 The Royal Society of Chemistry.

Experimental and theoretical investigation of vibrational spectra of coordination polymers based on TCE-TTF.

Science.gov (United States)

Olejniczak, Iwona; Lapiński, Andrzej; Swietlik, Roman; Olivier, Jean; Golhen, Stéphane; Ouahab, Lahcène

2011-08-01

The room-temperature infrared and Raman spectra of a series of four isostructural polymeric salts of 2,3,6,7-tetrakis(2-cyanoethylthio)-tetrathiafulvalene (TCE-TTF) with paramagnetic (Co(II), Mn(II)) and diamagnetic (Zn(II), Cd(II)) ions, together with BF(4)(-) or ClO(4)(-) anions are reported. Infrared and Raman-active modes are identified and assigned based on theoretical calculations for neutral and ionized TCE-TTF using density functional theory (DFT) methods. It is confirmed that the TCE-TTF molecules in all the materials investigated are fully ionized and interact in the crystal structure through cyanoethylthio groups. The vibrational modes related to the C=C stretching vibrations of TCE-TTF are analyzed assuming the occurrence of electron-molecular vibration coupling (EMV). The presence of the antisymmetric C=C dimeric mode provides evidence that charge transfer takes place between TCE-TTF molecules belonging to neighboring polymeric networks. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frequency dependent magneto-transport in charge transfer Co(II) complex

Energy Technology Data Exchange (ETDEWEB)

Shaw, Bikash Kumar; Saha, Shyamal K., E-mail: cnssks@iacs.res.in

2014-09-01

A charge transfer chelated system containing ferromagnetic metal centers is the ideal system to investigate the magneto-transport and magneto-dielectric effects due to the presence of both electronic as well as magnetic properties and their coupling. Magneto-transport properties in materials are usually studied through dc charge transport under magnetic field. As frequency dependent conductivity is an essential tool to understand the nature of carrier wave, its spatial extension and their mutual interaction, in the present work, we have investigated frequency dependent magneto-transport along with magnetization behavior in [Co{sub 2}(II)-(5-(4-PhMe)-1,3,4-oxadiazole-H{sup +}-2-thiolate){sub 5}](OAc){sub 4} metal complex to elucidate the nature of above quantities and their response under magnetic field in the transport property. We have used the existing model for ac conduction incorporating the field dependence to explain the frequency dependent magneto-transport. It is seen that the frequency dependent magneto-transport could be well explained using the existing model for ac conduction. -Highlights: • Chelated Co(II) complex is synthesized for magneto-transport applications. • Frequency dependent magneto-transport and magnetization behavior are studied. • Nature of carrier wave, its spatial extension is investigated under magnetic field. • Existing model for ac conduction is used with magnetic field dependence.

Synthesis and pharmacological evaluation of N-substituted 2-(2-oxo-2H-chromen-4-yloxy)propanamide as cyclooxygenase inhibitors.

Science.gov (United States)

Rambabu, D; Mulakayala, Naveen; Ismail; Kumar, K Ravi; Kumar, G Pavan; Mulakayala, Chaitanya; Kumar, Chitta Suresh; Kalle, Arunasree M; Rao, M V Basaveswara; Oruganti, Srinivas; Pal, Manojit

2012-11-01

A series of novel N-substituted 2-(2-oxo-2H-chromen-4-yloxy)propanamide derivatives were synthesized via converting the readily available 4-hydroxy coumarin to the corresponding ethyl 2-(2-oxo-2H-chromen-4-yloxy)propanoate followed by hydrolysis and then reacting with different substituted amines. The molecular structures of two representative compounds, that is, 3 and 5l were confirmed by single crystal X-ray diffraction study. All the compounds synthesized were evaluated for their cyclooxygenase (COX) inhibiting properties in vitro. The compound 5i showed balanced selectivity towards COX-2 over COX-1 inhibition and good docking scores when docked into the COX-2 protein. Copyright © 2012 Elsevier Ltd. All rights reserved.

Atom-type-based AI topological descriptors: application in structure-boiling point correlations of oxo organic compounds.

Science.gov (United States)

Ren, Biye

2003-01-01

Structure-boiling point relationships are studied for a series of oxo organic compounds by means of multiple linear regression (MLR) analysis. Excellent MLR models based on the recently introduced Xu index and the atom-type-based AI indices are obtained for the two subsets containing respectively 77 ethers and 107 carbonyl compounds and a combined set of 184 oxo compounds. The best models are tested using the leave-one-out cross-validation and an external test set, respectively. The MLR model produces a correlation coefficient of r = 0.9977 and a standard error of s = 3.99 degrees C for the training set of 184 compounds, and r(cv) = 0.9974 and s(cv) = 4.16 degrees C for the cross-validation set, and r(pred) = 0.9949 and s(pred) = 4.38 degrees C for the prediction set of 21 compounds. For the two subsets containing respectively 77 ethers and 107 carbonyl compounds, the quality of the models is further improved. The standard errors are reduced to 3.30 and 3.02 degrees C, respectively. Furthermore, the results obtained from this study indicate that the boiling points of the studied oxo compound dominantly depend on molecular size and also depend on individual atom types, especially oxygen heteroatoms in molecules due to strong polar interactions between molecules. These excellent structure-boiling point models not only provide profound insights into the role of structural features in a molecule but also illustrate the usefulness of these indices in QSPR/QSAR modeling of complex compounds.

Preparation, spectral, X-ray powder diffraction and computational studies and genotoxic properties of new azo-azomethine metal chelates

Science.gov (United States)

Bitmez, Şirin; Sayin, Koray; Avar, Bariş; Köse, Muhammet; Kayraldız, Ahmet; Kurtoğlu, Mükerrem

2014-11-01

A new tridentate azo-azomethine ligand, N‧-[{2-hydroxy-5-[(4-nitrophenyl)diazenyl]phenyl}methylidene]benzohydrazidemonohydrate, (sbH·H2O) (1), is prepared by condensation of benzohydrazide and 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde (a) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in EtOH. The five coordination compounds, [Co(sb)2]·4H2O (2), [Ni(sb)2]·H2O (3), [Cu(sb)2]·4H2O (4), [Zn(sb)2]·H2O (5) and [Cd(sb)2]·H2O (6) are prepared by reacting the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with the ligand. The structures of the compounds are elucidated from the elemental analyses data and spectroscopic studies. It is found the ligand acts as a tridentate bending through phenolic and carbonyl oxygens and nitrogen atom of the Cdbnd Nsbnd group similar to the most of salicylaldimines. Comparison of the infrared spectra of the ligand and its metal complexes confirm that azo-Schiff base behaves as a monobasic tridentate ligand towards the central metal ion with an ONO donor sequence. Upon complexation with the ligand, the Cd(II), and Zn(II) ions form monoclinic structures, while Co(II), Cu(II) and Ni(II) ions form orthorhombic structures. Quantum chemical calculations are performed on tautomers and its metal chelates by using DFT/B3LYP method. Most stable tautomer is determined as tautomer (1a). The geometrical parameters of its metal chelates are obtained as theoretically. The NLO properties of tautomer (1a) and its metal complexes are investigated. Finally, the ligand and its metal complexes are assessed for their genotoxicity.

Effects of metal-ion replacement on pyrazinamidase activity: A quantum mechanical study.

Science.gov (United States)

Khadem-Maaref, Mahmoud; Mehrnejad, Faramarz; Phirouznia, Arash

2017-05-01

Pyrazinamidase (PZase), a metalloenzyme, is responsible for acidic modification of pyrazinamide (PZA), a drug used in tuberculosis treatment. The metal coordination site of the enzyme is able to coordinate various divalent metal cofactors. Previous experimental studies have demonstrated that metal ions, such as Co 2+ , Mn 2+ , and Zn 2+ , are able to reactivate metal-depleted PZase, while others including Cu 2+ , Fe 2+ , and Mg 2+ , cannot restore activity. In this study, we investigated binding of various metal ions to the metal coordination site (MCS) of the enzyme using quantum mechanical calculations. We calculated the metal-ligand (residue) binding energy and the atomic partial charges in the presence of various ions. The results indicated that the tendency of alkaline earth metals to bind to PZase MCS is very low and not suitable for enzyme structural and catalytic function. In contrast, Co 2+ and Ni 2+ ions have very high binding affinity and are favorable to the structural and functional properties of the enzyme. Furthermore, we observed that the rate at which Ni 2+ , Co 2+ and Fe 2+ ions in PZase MCS polarize the OH bond of coordinated water molecules is much higher than the polarization rate created by other ions. This finding suggests that the coordination of Ni 2+ , Co 2+ , or Fe 2+ to PZase facilitates the deprotonation of coordinated water molecules to generate a nucleophile that catalyzes the enzymatic reaction. Copyright © 2017 Elsevier Inc. All rights reserved.

Use of mass spectrometry for study of coordination compounds

International Nuclear Information System (INIS)

Gehrbehlehu, N.V.; Indrichan, K.M.

1981-01-01

A review on mass-spectrometry of coordination compounds including the works published up to 1979 inclusive is provided. Mainly the products of metals with bi- and tetradentate ligands are considered using the method. Mo and Be carboxylates for which molecular ions lines are found in mass-spectra are studied. The study of mass-spectra for VO chelates with thiosemicarbazone of salicyl aldehyde is carried out. Application of the mass-spectrometry method permits to establish the mass of coordination compounds, the structure of complexes, dentate structure and the way of ligand coordination, the bond strength [ru

Quantitation of movement of the phosphoryl group during catalytic transfer in the arginine kinase reaction: 31P relaxation measurements on enzyme-bound equilibrium mixtures

International Nuclear Information System (INIS)

Ray, Bruce D.; Jarori, Gotam K.; Nageswara Rao, B.D.

2002-01-01

31 P nuclear spin relaxation measurements have been made on enzyme-bound equilibrium mixtures of lobster-muscle arginine kinase in the presence of substituent activating paramagnetic cation Co(II) (in place of Mg(II)), i.e., on samples in which the reaction, E·CoATP·arginine ↔ E·CoADP·P-arginine, is in progress. The results have been analyzed on the basis of a previously published theory (Nageswara Rao, B.D. (1995) J. Magn. Reson., B108, 289-293) to determine the structural changes in the reaction complex accompanying phosphoryl transfer. The analysis enables the determination of the change in the Co(II)- 31 P (γ-P(ATP)) vector as the transferable phosphoryl group moves over and attaches to arginine to form P-arginine. It is shown that the Co(II)- 31 P distance of ∼3.0 A, representing direct coordination of Co(II) to γ-P(ATP), changes to ∼4.0 A when P-arginine is formed in the enzyme-bound reaction complex. This elongation of the Co(II)- 31 P vector implies an excursion of at least 1.0 A for the itinerant phosphoryl group on the surface of the enzyme

2 : 2 Fe(III): ligand and "adamantane core" 4 : 2 Fe(III): ligand (hydr)oxo complexes of an acyclic ditopic ligand

DEFF Research Database (Denmark)

Ghiladi, Morten; Larsen, Frank B.; McKenzie, Christine J.

2005-01-01

A bis-hydroxo-bridged diiron(III) complex and a bis-mu-oxo-bis-mu-hydroxo-bridged tetrairon( III) complex are isolated from the reaction of 2,6-bis((N, N'-bis-(2-picolyl) amino) methyl)-4-tert-butylphenol (Hbpbp) with iron perchlorate in acidic and neutral solutions respectively. The X-ray struct......A bis-hydroxo-bridged diiron(III) complex and a bis-mu-oxo-bis-mu-hydroxo-bridged tetrairon( III) complex are isolated from the reaction of 2,6-bis((N, N'-bis-(2-picolyl) amino) methyl)-4-tert-butylphenol (Hbpbp) with iron perchlorate in acidic and neutral solutions respectively. The X...

Association between 8-oxo-7,8-dihydro-2'-deoxyguanosine excretion and risk of postmenopausal breast cancer

DEFF Research Database (Denmark)

Loft, Steffen; Olsen, Anja; Møller, Peter

2013-01-01

Oxidative stress may be important in carcinogenesis and a possible risk factor for breast cancer. The urinary excretion of oxidatively generated biomolecules, such as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), represents biomarkers of oxidative stress, reflecting the rate of global damage...

4-[4-(4-Fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-3-yl]-1-methylpyridinium iodide–4-[3-(4-fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-4-yl]-1-methylpyridinium iodide (0.6/0.4

Directory of Open Access Journals (Sweden)

Simona Margutti

2008-01-01

Full Text Available The crystal structure of the title compound, C16H16FN2O2+·I−, was determined as part of a study of the biological activity of isoxazolone derivatives as p38 mitogen-activated protein kinase (MAPK inhibitors. The X-ray crystal structure of 4-[4-(4-fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-3-yl]-1-methylpyridinium iodide showed the presence of the regioisomer 4-[3-(4-fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-4-yl]-1-methylpyridinium iodide. The synthesis of the former compound was achieved by reacting 4-(4-fluorophenyl-3-(4-pyridylisoxazol-5(2H-one after treatment with Et3N in dimethylformamide, with iodomethane. The unexpected formation of the regioisomer could be explained by a rearrangement occurring via aziridine of the isoxazolone compound. The regioisomers have site occupancies of 0.632 (4/0.368 (4. The two six members rings make a dihedral angle of 66.8 (2°.

On the solvation of actinide ions

International Nuclear Information System (INIS)

Hagberg, D.

2007-01-01

Complete text of publication follows: Simulation of the universal ions in water solution is a standardized tool commonly used today. The route to simulation of actinide ions is normally tough because the evaluation of the simulation parameters are normally not given empirically and standard Hartree-Fock calculations are not accurate enough. We use multiconfigurational quantum chemical calculations when deriving the parameters for actinide ion-water potential [1]. The parameters are then simulated using classical molecular dynamics. A case study of the Cm 3+ ion will be presented on the poster. Results from the simulations will be also be discussed, e.g. the radial distribution functions and the coordination number. [1] D. Hagberg, G. Karlstrom, B.O. Roos and L. Gagliardi The coordination of uranyl in water: a combined quantum chemical and molecular simulation study J. Am. Chem. Soc. 127, 14250-14256 (2005)

Metal ion interaction with phosphorylated tyrosine analogue monolayers on gold.

Science.gov (United States)

Petoral, Rodrigo M; Björefors, Fredrik; Uvdal, Kajsa

2006-11-23

Phosphorylated tyrosine analogue molecules (pTyr-PT) were assembled onto gold substrates, and the resulting monolayers were used for metal ion interaction studies. The monolayers were characterized by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), both prior to and after exposure to metal ions. XPS verified the elemental composition of the molecular adsorbate and the presence of metal ions coordinated to the phosphate groups. Both the angle-dependent XPS and IRAS results were consistent with the change in the structural orientation of the pTyr-PT monolayer upon exposure to metal ions. The differential capacitance of the monolayers upon coordination of the metal ions was evaluated using EIS. These metal ions were found to significantly change the capacitance of the pTyr-PT monolayers in contrast to the nonphosphorylated tyrosine analogue (TPT). CV results showed reduced electrochemical blocking capabilities of the phosphorylated analogue monolayer when exposed to metal ions, supporting the change in the structure of the monolayer observed by XPS and IRAS. The largest change in the structure and interfacial capacitance was observed for aluminum ions, compared to calcium, magnesium, and chromium ions. This type of monolayer shows an excellent capability to coordinate metal ions and has a high potential for use as sensing layers in biochip applications to monitor the presence of metal ions.

N-(sulfoethyl) iminodiacetic acid-based lanthanide coordination polymers: Synthesis, magnetism and quantum Monte Carlo studies

Energy Technology Data Exchange (ETDEWEB)

Zhuang Guilin, E-mail: glzhuang@zjut.edu.cn [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Chen Wulin [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Zheng Jun [Center of Modern Experimental Technology, Anhui University, Hefei 230039 (China); Yu Huiyou [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Wang Jianguo, E-mail: jgw@zjut.edu.cn [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China)

2012-08-15

A series of lanthanide coordination polymers have been obtained through the hydrothermal reaction of N-(sulfoethyl) iminodiacetic acid (H{sub 3}SIDA) and Ln(NO{sub 3}){sub 3} (Ln=La, 1; Pr, 2; Nd, 3; Gd, 4). Crystal structure analysis exhibits that lanthanide ions affect the coordination number, bond length and dimension of compounds 1-4, which reveal that their structure diversity can be attributed to the effect of lanthanide contraction. Furthermore, the combination of magnetic measure with quantum Monte Carlo(QMC) studies exhibits that the coupling parameters between two adjacent Gd{sup 3+} ions for anti-anti and syn-anti carboxylate bridges are -1.0 Multiplication-Sign 10{sup -3} and -5.0 Multiplication-Sign 10{sup -3} cm{sup -1}, respectively, which reveals weak antiferromagnetic interaction in 4. - Graphical abstract: Four lanthanide coordination polymers with N-(sulfoethyl) iminodiacetic acid were obtained under hydrothermal condition and reveal the weak antiferromagnetic coupling between two Gd{sup 3+} ions by Quantum Monte Carlo studies. Highlights: Black-Right-Pointing-Pointer Four lanthanide coordination polymers of H{sub 3}SIDA ligand were obtained. Black-Right-Pointing-Pointer Lanthanide ions play an important role in their structural diversity. Black-Right-Pointing-Pointer Magnetic measure exhibits that compound 4 features antiferromagnetic property. Black-Right-Pointing-Pointer Quantum Monte Carlo studies reveal the coupling parameters of two Gd{sup 3+} ions.

Synthesis, crystal structure and properties of [Co(L2](ClO42 (L=1,3-bis(1H-benzimidazol-2-yl-2-oxapropane

Directory of Open Access Journals (Sweden)

Tavman Aydin

2015-01-01

Full Text Available The reaction of 1,3-bis(1H-benzimidazol-2-yl-2-oxapropane (L with Co(ClO42•6H2O in absolute ethanol produces di[1,3-bis(1H-benzimidazol-2-yl-2-oxapropane-k2N,N’]cobalt(IIdiperchlorate chelate complex ([Co(L2](ClO42, 1. The complex 1 was characterized by elemental analysis, magnetic moment, molar conductivity, thermogravimetric analysis, FT-IR, UV-visible, mass spectrometry, and its solid state structure was determined by single crystal X-ray diffraction. According to the thermogravimetric analysis data, there is no any water coordinated or uncoordinated in 1 as well as elemental analysis. The complex 1 has 1:2 M:L ionic characteristic according to the molar conductivity. In the complex, the distances between the cobalt and the ethereal oxygen atoms (Co1-O2: 2.805(3; Co2-O1: 2.752(2 Å show the semi-coordination bonding and the Co(II ion is six-coordinated with a N4O2 ligand set, resulting in a distorted octahedron.

Phase I study of 6-diazo-5-oxo-L-norleucine (DON).

Science.gov (United States)

Sklaroff, R B; Casper, E S; Magill, G B; Young, C W

1980-01-01

We conducted a phase I study of 6-diazo-5-oxo-L-norleucine given iv on a twice weekly schedule. Twenty-six evaluable patients received 31 courses of the drug. Doses ranged from 100 to 500 mg/m2. Nausea with vomiting was the dose-limiting toxic effect, transient thrombocytopenia was seen frequently, and mucositis occurred in 39% of the patients. No definite therapeutic responses were observed in 18 patients with measurable lesions. The recommended dose for phase II studies is 200-300 mg/m2 iv twice weekly.

Determination of some metal ions in various meat and baby food samples by atomic spectrometry.

Science.gov (United States)

Daşbaşı, Teslima; Saçmacı, Şerife; Ülgen, Ahmet; Kartal, Şenol

2016-04-15

In this paper, we report a simple and rapid solid phase extraction system for the separation/preconcentration and determination of Cd(II), Co(II), Cu(II), Fe(III), Cr(III), Pb(II), and Zn(II) ions by flame atomic absorption spectrometry (FAAS). This method is based upon the retention of metal ions on a column packed with poly[N-(3-methyl-1H-indole-1-yl)]-2-methacrylamide-co-2-acrylamido-2-methyl-1-propane sulphonic acid-co divinylbenzene] (MMAD) resin as a solid-phase extraction (SPE) sorbent at pH 8. At the optimized conditions, the limits of detection (3 s/b) between 0.12 and 1.6 μg L(-1), preconcentration factor of 100, and the relative standard deviation of ⩽1.8% were achieved (n=10). The accuracy of the method was verified by analyzing certified reference materials (CRMs) and performing recovery experiments. The developed method was successfully applied to the various natural water, meat products and baby food samples. The recoveries of analyte ions were found in added real samples and CRMs from 95% to 102%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Meso-Helical Ag(I) Coordination Polymer Based on a Pyridylimidazole Ligand

International Nuclear Information System (INIS)

Kang, Youngjin; Kim, Jinho; Lee, Eunji; Park, Ki-Min; Moon, Suk-Hee

2016-01-01

In the fields of material science and metallosupramolecular chemistry, coordination polymers with various helical types have been extensively explored because of their charming structures, and their potential applications in material chemistry. Among them, meso-helical coordination polymers consisting of achiral 1D strands, which are generally constructed by a crystallographic inversion symmetry, are relatively rare. The coordination polymer 1 exhibits a rare one-dimensional meso-helical chain topology constructed by its internal inversion symmetry. The skeleton of this meso-helical chain is preserved up to 300°C. The complexation of silver(I) ion to the free pyim ligand give rise to the enhanced photoluminescence intensity and slightly blue-shifted emission maximum, originated from intraligand (IL) π[BOND]π* transition and rigidochromic effect. Further exploration of complexation of this ligand with other transition metal ions is currently in progress

Carboxylate ligands drastically enhance the rates of oxo exchange and hydrogen peroxide disproportionation by oxo manganese compounds of potential biological significance.

Science.gov (United States)

Dubois, Lionel; Pécaut, Jacques; Charlot, Marie-France; Baffert, Carole; Collomb, Marie-Noëlle; Deronzier, Alain; Latour, Jean-Marc

2008-01-01

To mimic the carboxylate-rich active site of the manganese catalases more closely we introduced carboxylate groups into dimanganese complexes in place of nitrogen ligands. The series of dimanganese(III,IV) complexes of tripodal ligands [Mn(2)(L)(2)(O)(2)](3+/+/-/3-) was extended from those of tpa (1) and H(bpg) (2) to those of H(2)(pda) (3) and H(3)(nta) (4) (tpa=tris-picolylamine, H(bpg)=bis-picolylglycylamine, H(2)(pda)=picolyldiglycylamine, H(3)(nta)=nitrilotriacetic acid). While 3 [Mn(2)(pda)(2)(O)(2)][Na(H(2)O)(3)] could be synthesized at -20 degrees C and characterized in the solid state, 4 [Mn(2)(nta)(2)(O)(2)](3-) could be obtained and studied only in solution at -60 degrees C. A new synthetic procedure for the dimanganese(III,III) complexes was devised, using stoichiometric reduction of the dimanganese(III,IV) precursor by the benzil radical with EPR monitoring. This enabled the preparation of the parent dimanganese(III,III) complex 5 [Mn(2)(tpa)(2)(O)(2)](ClO(4))(2), which was structurally characterized. The UV/visible, IR, EPR, magnetic, and electrochemical properties of complexes 1-3 and 5 were analyzed to assess the electronic changes brought about by the carboxylate replacement of pyridine ligands. The kinetics of the oxo ligand exchanges with labeled water was examined in acetonitrile solution. A dramatic effect of the number of carboxylates was evidenced. Interestingly, the influence of the second carboxylate substitution differs from that of the first one probably because this substitution occurs on an out-of-plane coordination while the former occurs in the plane of the [Mn(2)O(2)] core. Indeed, on going from 1 to 3 the exchange rate was increased by a factor of 50. Addition of triethylamine caused a rate increase for 1, but not for 3. The abilities of 1-3 to disproportionate H(2)O(2) were assessed volumetrically. The disproportionation exhibited a sensitivity corresponding to the carboxylate substitution. These observations strongly suggest that

Preparation, characterization, magnetic and thermal studies of some chelate polymers of first series transition metal ions

International Nuclear Information System (INIS)

Ukey, Vaishali V.; Juneja, H.D.; Borkar, S.D.; Ghubde, R.S.; Naz, S.

2006-01-01

Azelaoyl-bis-hydroxamic acid used as bis ligand for the preparation of chelate polymers of Mn(II), Co(II), Ni(II) and Zn(II). These chelate polymers have been synthesized by refluxing the metal acetate and bis ligand as 1:1 stoichiometry. In the present work, structural determination of these newly synthesized chelate polymers has been studied on the basis of elemental analyses, infrared and reflectance spectral, magnetic and thermal studies. The decomposition temperature and the order of reaction have been determined by TGA analysis. On the basis of these studies, the Zn(II) chelate polymer has tetrahedral geometry, whereas Mn(II), Co(II) and Ni(II) chelate polymers have octahedral geometry and have the thermal stability in the order Ni(II) > Mn(II) > Zn(II) > Co(II)

8-oxo-7,8-dihydroguanine level - the DNA oxidative stress marker - recognized by fluorescence image analysis in sporadic uterine adenocarcinomas in women.

Science.gov (United States)

Postawski, Krzysztof; Przadka-Rabaniuk, Dorota; Piersiak, Tomasz

2013-01-01

In the case of carcinogenesis in human endometrium no information exists on tissue concentration of 8-oxo-7,8-dihydroguanine, the DNA oxidative stress marker This was the main reason to undertake the investigation of this DNA modification in human uterine estrogen-dependent tissue cancers. In order to estimate the level of oxidative damage, 8-oxo-7,8-dihydroguanine was determined directly in cells of tissue microscope slides using OxyDNA Assay Kit, Fluorometric. Cells were investigated under confocal microscope. Images of individual cells were captured by computer-interfaced digital photography and analyzed for fluorescence intensities (continuous inverted 8-bit gray-scale = 0 [black]-255 [white]). Fluorescence scores were calculated for each of 13 normal endometrial samples and 31 uterine adenocarcinoma specimens. Finally the level of the oxidative stress marker was also analyzed according to histological and clinical features of the neoplasms. The obtained data revealed that: 8-oxo-7,8-dihydroguanine levels were higher in uterine adenocarcinomas than in normal endometrial samples (48,32 vs. 38,64; p<0,001); in contrast to normal endometrium there was no correlation between age and DNA oxidative modification content in uterine cancer; highest mean fluorescence intensity was recognized in G2 endometrial adenocarcinomas; level of 8-oxo-7,8-dihydroguanine does not depend on Body Mass Index (BMI) and cancer uterine wall infiltration or tumor FIGO stage. Our study indicates that accumulation of the oxidized DNA base may contribute to the development of endometrial neoplasia, however oxidative DNA damage does not seem to increase with tumor progression.

Potentiometric and spectroscopic study of the interaction of 3d transition metal ions with inositol hexakisphosphate

Science.gov (United States)

Veiga, Nicolás; Macho, Israel; Gómez, Kerman; González, Gabriel; Kremer, Carlos; Torres, Julia

2015-10-01

Among myo-inositol phosphates, the most abundant in nature is the myo-inositol hexakisphosphate, InsP6. Although it is known to be vital to cell functioning, the biochemical research into its metabolism needs chemical and structural analysis of all the protonation, complexation and precipitation processes that it undergoes in the biological media. In view of its high negative charge at physiological level, our group has been leading a thorough research into the InsP6 chemical and structural behavior in the presence of the alkali and alkaline earth metal ions essential for life. The aim of this article is to extend these studies, dealing with the chemical and structural features of the InsP6 interaction with biologically relevant 3d transition metal ions (Fe(II), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)), in a non-interacting medium and under simulated physiological conditions. The metal-complex stability constants were determined by potentiometry, showing under ligand-excess conditions the formation of mononuclear species in different protonation states. Under metal ion excess, polymetallic species were detected for Fe(II), Fe(III), Zn(II) and Cu(II). Additionally, the 31P NMR and UV-vis spectroscopic studies provided interesting structural aspects of the strong metal ion-InsP6 interaction.

Synthesis and properties of new polyimide/clay nanocomposite films

Indian Academy of Sciences (India)

layers bound by ionic bonding with metal cations such as. Na. + ... the exchange of sodium ions with organic alkylammonium ions. ... 3 wt% of organoclay concentration in the hybrid formed by ... toward heavy and toxic metal ions such as Cu(II), Co(II) and .... and different dianhydrides via poly(amic acid) intermediates.

A novel one-dimensional chain built of vanadyl ions and pyrazine-2,5-dicarboxylate

NARCIS (Netherlands)

Lankelma, M.; de Boer, J.; Ferbinteanu, M.; Dantas Ramos, A.L.; Tanasa, R.; Rothenberg, G.; Tanase, S.

2015-01-01

We present a new coordination polymer, {[VO(pzdc)(H2O)(2)] H2O}(n), built from vanadyl and pyrazine-2,5-dicarboxylate (pzdc) ions. It consists of a one-dimensional chain of vanadyl ions linked by pzdc ions. The carboxylate groups show monodentate coordination, while the pyrazine ring is present both

Redox reactivity and coordination chemistry of uranium

International Nuclear Information System (INIS)

Nocton, G.

2009-09-01

The study and the understanding of actinides chemistry have important implications in the nuclear field both for the development of new actinides materials and the retreatment of the nuclear wastes. One of the major issues in that chemistry is that the actinides elements are known to undergo redox reaction and to form assemblies of different size and different topologies. In that context uranium can be a good model of the heavier radioelement because it is much less radioactive. So, this work concerns the synthesis and the study of the spectroscopy and the magnetic properties of several uranium based polymetallic assemblies synthesized by taking advantage of the redox properties and the coordination chemistry of uranium. The hydrolysis reactivity of trivalent uranium has been studied in absence of sterically hindered ligands and led to the synthesis of oxo/hydroxo uranium assemblies with different sizes by changing the starting complex or the reaction conditions. By following the same strategy, the controlled oxidation of trivalent uranium complexes led to an original azido/nitrido uranium complex. The coordination chemistry of the pentavalent uranyl polymer {[UO 2 py 5 ][KI 2 py 3 ]} n has also been studied with different ligand and in different conditions and led to several cation-cation complexes for which the stability is sufficient for studying there dismutation by proton NMR. By changing the ancillary ligands stable monomeric complexes of pentavalent uranyl complexes were also obtained. The magnetic properties of all the complexes, monomers and polymetallic complexes were studied and an antiferromagnetic coupling was observed for the cation-cation pentavalent uranyl dimer [UO 2 (dbm) 2 (K 18 C 6 )] 2 . (author)

A Comparative Study of the Inclusion Complexes of 2-[5'-benzylidene-2'-phenyl-4'-oxo-1', 3'-thiazolidine]-1, 3-benzothiazole and 2-[5'-(p-N,N-dimethylamino- benzylidene-2'-phenyl-4'-oxo-1', 3'-thiazolidine]-1, 3-benzothiazole withβ-Cyclodextrin

Directory of Open Access Journals (Sweden)

S. Panda

2011-01-01

Full Text Available The compounds 2-[5'-benzylidene-2'-phenyl-4'-oxo-1', 3'-thiazolidine]-1, 3-benzothiazole and 2-[5'-(p-N,N-dimethylamino- benzylidene-2'-phenyl-4'-oxo-1', 3'-thiazolidine]-1, 3-benzothiazole have been synthesized in their purest forms starting from 2-aminobenzothiazole. The inclusion complexes of the above compounds have been prepared with β-cyclodextrin to increase their solubility and bioaccessibility in polar medium. The formation of inclusion complexes have been ascertained by study of spectral characteristic before and after inclusion complex formation. The stability of inclusion complexes and nature of interaction between the host and guest are known from the determination of thermodynamic parameters. Further the antibacterial and antifungal activities of the compounds are determined which is found to increase significantly after inclusion complex formation

Substrate specificity, metal binding properties, and spectroscopic characterization of the DapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase from Haemophilus influenzae.

Science.gov (United States)

Bienvenue, David L; Gilner, Danuta M; Davis, Ryan S; Bennett, Brian; Holz, Richard C

2003-09-16

The catalytic and structural properties of divalent metal ion cofactor binding sites in the dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae were investigated. Co(II)-substituted DapE enzyme was 25% more active than the Zn(II)-loaded form of the enzyme. Interestingly, Mn(II) can activate DapE, but only to approximately 20% of the Zn(II)-loaded enzyme. The order of the observed k(cat) values are Co(II) > Zn(II) > Cd(II) > Mn(II) >Ni(II) approximately equal Cu(II) approximately equal Mg(II). DapE was shown to only hydrolyze L,L-N-succinyl-diaminopimelic acid (L,L-SDAP) and was inactive toward D,L-, L,D-, and D,D-SDAP. DapE was also inactive toward several acetylated amino acids as well as D,L-succinyl aminopimelate, which differs from the natural substrate, L,L-SDAP, by the absence of the amine group on the amino acid side chain. These data imply that the carboxylate of the succinyl moiety and the amine form important interactions with the active site of DapE. The affinity of DapE for one versus two Zn(II) ions differs by nearly 2.2 x 10(3) times (K(d1) = 0.14 microM vs K(d2) = 300 microM). In addition, an Arrhenius plot was constructed from k(cat) values measured between 16 and 35 degrees C and was linear over this temperature range. The activation energy for [ZnZn(DapE)] was found to be 31 kJ/mol with the remaining thermodynamic parameters calculated at 25 degrees C being DeltaG(++) = 64 kJ/mol, DeltaH(++) = 28.5 kJ/mol, and DeltaS(++) = -119 J mol(-1) K(-1). Electronic absorption and EPR spectra of [Co_(DapE)] and [CoCo(DapE)] indicate that the first Co(II) binding site is five-coordinate, while the second site is octahedral. In addition, any spin-spin interaction between the two Co(II) ions in [CoCo(DapE)] is very weak. The kinetic and spectroscopic data presented herein suggest that the DapE from H. influenzae has similar divalent metal binding properties to the aminopeptidase from Aeromonas proteolytica (AAP), and

Coordination symmetry determination of some lanthanide complexes by x-ray diffraction

International Nuclear Information System (INIS)

Oliveira Paiva Santos, C. de.

1983-01-01

The x-ray determination of the crystal and molecular structures of three lanthanide complexes is described. The work is a contribution to the study of the coordination chemistry of lanthanide ions with organic ligands and in particular, it aims to compare the observed point symmetry of the ion environment with spectroscopic predictions. (author)

Characterization of diatomite and its application for the retention of radiocobalt: role of environmental parameters

International Nuclear Information System (INIS)

Sheng, Guodong; Dong, Huaping; Li, Yimin

2012-01-01

Clay minerals have been extensively studied because of their strong sorption and complexation ability. In this work, diatomite was characterized by using acid–base titration. Retention of radionuclide 60 Co(II) from aqueous solution by sorption onto diatomite was investigated by using batch technique under various environmental conditions such as pH, ionic strength, humic acid (HA), fulvic acid (FA), and temperature. The results indicated that the sorption of Co(II) onto diatomite was strongly dependent on pH. At low pH value, the sorption of Co(II) was dominated by outer-sphere surface complexation and ion exchange with Na + /H + on diatomite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH value. The D–R model fitted the sorption isotherms better than the Langmuir and Freundlich models. The thermodynamic parameters (ΔH 0 , ΔS 0 and ΔG 0 ) calculated from the temperature-dependent sorption isotherms suggested that the sorption of Co(II) was an endothermic and spontaneous process. In addition, diatomite showed higher sorption capacity than that of lots of the sorbents reported in the literatures we surveyed. From the results of Co(II) removal by diatomite, the optimum reaction conditions can be obtained for the maximum removal of Co(II) from water. It is clear that the best pH values of the system to remove Co(II) from solution by using diatomite are 7–8. Considering the low cost and effective disposal of Co(II)-contaminated wastewaters, the best condition for Co(II) removal is at room temperature and solid content of 0.5 g/L. The results might be important for assessing the potential of practical application of diatomite in Co(II) and related radionuclide pollution management. - Highlights: ► The sorption of Co(II) was strongly dependent on ionic strength at low pH, but independent of ionic strength at high pH. ► A positive effect of HA/FA on Co(II) sorption was found at low pH, whereas a negative effect

Solvent extraction of some metal ions by dithiocarbamate types of chemically modified lipophilic chitosan

International Nuclear Information System (INIS)

Inoue, K.; Nakagawa, H.; Naganawa, H.; Tachimori, S.

2001-01-01

Chitosan is a basic polysaccharide containing primary amino groups with high reactivity. we prepared O,O'-decanoyl chitosan and dithiocarbamate O,O'-decanoyl chitosan; the former was soluble in chloroform and toluene, while latter was soluble not only these diluents but also in some aliphatic diluents such as hexane and kerosene which are employed in commercial scale solvent extraction. Solvent extraction by dithiocarbamate O,O'-decanoyl chitosan in kerosene was tested for some base metal ions from sulfuric acid solution. The sequence of selectivity for these metal ions was found to be as follows: Cu(II) >> Ni(II) > Cd(II) ∼ Fe(III) > Co(II) ∼ Zn(II). Copper(II) was quantitatively extracted at pH > 1 and quantitatively stripped with 2 M sulfuric acid solution. Solvent extraction of silver(I) and gold(III) from hydrochloric acid as well as lanthanides and americium(III) from nitrate solution were also tested. Americium was selectively extracted over trivalent lanthanides, suggesting a high possibility for the final treatment of high level radioactive wastes. (authors)

Design and synthesis of brain-targeted prodrugs of the glutamine antagonist 6-Diazo-5-oxo-L-norleucine

Czech Academy of Sciences Publication Activity Database

Tenora, Lukáš; Novotná, Kateřina; Monincová, Lenka; Jančařík, Andrej; Nedelcovych, M.; Alt, J.; Rais, R.; Slusher, B. S.; Majer, Pavel

2017-01-01

Roč. 284, Suppl 1 (2017), s. 344 ISSN 1742-464X. [FEBS Congress /42./ From Molecules to Cells and Back. 10.09.2017-14.09.2017, Jerusalem] Institutional support: RVO:61388963 Keywords : 6-Diazo-5-oxo-L-norleucine * prodrugs Subject RIV: CE - Biochemistry

Design and synthesis of brain-targeted prodrugs of the glutamine antagonist 6-Diazo-5-oxo-L-norleucine

Czech Academy of Sciences Publication Activity Database

Tenora, Lukáš; Novotná, Kateřina; Monincová, Lenka; Jančařík, Andrej; Gadiano, A. J.; Dash, R.; Rais, R.; Alt, J.; Slusher, B. S.; Majer, Pavel

2017-01-01

Roč. 284, Suppl 1 (2017), s. 345 ISSN 1742-464X. [FEBS Congress /42./ From Molecules to Cells and Back. 10.09.2017-14.09.2017, Jerusalem] Institutional support: RVO:61388963 Keywords : 6-Diazo-5-oxo-L-norleucine * prodrugs Subject RIV: CE - Biochemistry

Useful forms of the Hamiltonian for ion-optical systems

International Nuclear Information System (INIS)

Davies, W.G.

1991-04-01

The symbiosis of differential algebra and the Lie-algebraic formulation of optics provides a set of very powerful tools for analyzing and understanding the orbit dynamics of complex accelerators up to very high orders. In order to use these tools effectively it is usually necessary to express the Hamiltonian in the appropriate coordinate system. In this report, the relativistic Hamiltonian is derived in curvilinear (the fundamental coordinate system for ion-optics), Cartesian and polar coordinates, in forms suitable for solving problems in ion optics and accelerator physics both with and without the help of differential algebra

Ion-Assisted Pulsed Laser Deposition of amorphous tetrahedral-coordinated carbon films

Science.gov (United States)

Friedmann, T. A.; Tallant, D. R.; Sullivan, J. P.; Siegal, M. P.; Simpson, R. L.

1994-04-01

A parametric study has been performed of amorphous tetrahedral carbon (a-tC) films produced by ion-assisted pulsed laser deposition (IAPLD). The ion voltage, current density, and feed gas composition (nitrogen in argon) have been varied. The resultant films were characterized by thickness, residual stress, Raman spectroscopy, and electrical resistivity. The Raman spectra have been fit to two gaussian peaks, the so called graphitic (G) peak and the disorder (D) peak. It has been found that the magnitude of the D peak and the residual compressive stress are inversely correlated. At low beam voltages and currents, the magnitude of the D peak is low, increasing as the ion beam voltage and current are raised. The ion beam voltage has the most dramatic effect on the magnitude of the D peak. At low voltages (200-500 V) the magnitude of the D peak is greater for ion beams with high percentages of nitrogen possibly indicative of C-N bonding in the films. At higher voltages (500-1500 V) the D peak intensity is less sensitive to the nitrogen content of the beam.

Coordination Chemistry of Linear Oligopyrrolic Fragments Inspired by Heme Metabolites

Science.gov (United States)

Gautam, Ritika

at 635 nm. This reaction also explains the antioxidant properties of the linear tripyrrin-1,14-dione ligand, which acts as a scavenger of O2•-. In Chapter 4, the zinc binding properties of the tripyrrin-1,14-dione ligand are described. The tripyrrolic ligand coordinates as a dianionic ligand with the divalent Zn(II) ion in both organic and aqueous buffered conditions. The complex formed is highly fluorescent with a long wavelength emission band at 648 nm. The X-Ray crystallography analysis indicates the existence of dinuclear complex [Zn(TD1•)(H2O)]2, featuring a distorted square planar geometry around the Zn(II) center. In Chapter 5, the coordination chemistry of the dipyrrin-1,9-dione fragment of propentdyopent ligand is shown with a series of transition metals like (e.g., Co(II), Ni(II), Cu(II) and Zn(II)), which form homoleptic tetrahedral complexes. The spectroscopic and electrochemical characterization confirms that the complexes shows ligand-based redox chemistry and acts as reservoirs for unpaired electrons. Chapter 6 describes the formation of the fluorescent BODIPY complex of propentdyopent ligand. The dipyrrin-1,9-dione scaffold of heme metabolite propendyopent undergoes a one-pot reaction with borontrifluoride etherate in toluene to form a green fluorescent [(pdp)BF2] complex. Spectroscopic studies reveal that the meso-unsubstituted [(pdp)BF2] complex is stable in tetrahydrofuran and has a quantum yield of 0.13. Electrochemical studies confirm that the complex undergoes ligand-based reduction and acts as a host for an unpaired electron.

Controlled deprotection and reorganization of uranyl oxo groups in a binuclear macrocyclic environment

International Nuclear Information System (INIS)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B.

2012-01-01

The silylated uranium(V) dioxo complex [(Me_3SiOUO)_2(L)_2] is inert to oxidation, but after two-electron reduction to [(Me_3SiOUO)_2(L)]"2"-, it can be desilylated to form [OU(μ-O)_2UO(L)_2]"2"- with reinstated uranyl character. Removal of the silyl group uncovers new redox and oxo rearrangement chemistry for uranium, thus reforming the uranyl motif and involving the U"V"I"/"V couple in dioxygen reduction. [de

One dimensional coordination polymers: Synthesis, crystal structures and spectroscopic properties

Science.gov (United States)

Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Şahin, Onur

2016-11-01

Two new one dimensional (1D) cyanide complexes, namely [M(4-aepy)2(H2O)2][Pt(CN)4], (4-aepy = 4-(2-aminoethyl)pyridine M = Cu(II) (1) or Zn(II) (2)), have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal and elemental analyses techniques. The crystallographic analyses reveal that 1 and 2 are isomorphous and isostructural, and crystallize in the monoclinic system and C2 space group. The Pt(II) ions are coordinated by four cyanide-carbon atoms in the square-planar geometry and the [Pt(CN)4]2- ions act as a counter ion. The M(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4-aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. The crystal structures of 1 and 2 are similar each other and linked via intermolecular hydrogen bonding, Pt⋯π interactions to form 3D supramolecular network. Vibration assignments of all the observed bands are given and the spectral features also supported to the crystal structures of the complexes.

Health status of cows fed maize silage covered with oxo-biodegradable foil

Directory of Open Access Journals (Sweden)

Piotr SZTERK

2017-11-01

Full Text Available In agricultural practice, silage production uses pure, low density polyethylene foil. This foil, after use, becomes farm waste, having a negative impact on the environment. Instead of conventional foil, an environmentally safe biodegradable foil can be used, made from naturally occurring polymers or from synthetic multiparticulates, easily degradable by microorganisms. Silage covered with this type of foil should be safe for animal health. The purpose of the study was to determine whether oxo-biodegradable film could be used instead of conventional film in agricultural practice, to produce silage that is safe for the cows' health. Dairy cows were fed a partly mixed ratio (PMR, the component of which was silage made of whole maize plants, covered with oxo-biodegradable foil. The cow blood serum was marked for content of: glucose, total protein, cholesterol, triacylglycerols and enzyme activity: aspartic and alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase and amylase. The total protein concentration in the serum of cows analyzed at the end of the experiment was higher than the commonly accepted normal values. The content of glucose, cholesterol, triacylglycerols and the activity of aspartate and alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase and amylase was within reference limits. Feeding of silage from whole maize plants covered withoxo-biodegradable foil did not negatively affect the biochemical indicators of the cows' blood serum. The silage proved to be safe for the cows' health.

Transition metal complexes of a new 15-membered [N5] penta-azamacrocyclic ligand with their spectral and anticancer studies

Science.gov (United States)

El-Boraey, Hanaa A.; Serag El-Din, Azza A.

2014-11-01

Novel penta-azamacrocyclic 15-membered [N5] ligand [L] i.e. 1,5,8,12-tetetraaza-3,4: 9,10-dibenzo-6-ethyl-7-methyl-1,12-(2,6-pyrido)cyclopentadecan-5,7 diene-2,11-dione and its transition metal complexes with Co(II), Ni(II), Cu(II), Ru(III) and Pd(II) have been synthesized and structurally characterized by elemental analysis, spectral, thermal as well as magnetic and molar conductivity measurements. On basis of IR, MS, UV-Vis 1H NMR and EPR spectral studies an octahedral geometry has been proposed for all complexes except Co(II), Cu(II) nitrate complexes and Pd(II) chloride complex that adopt tetrahedral, square pyramidal and square planar geometries, respectively. The antitumor activity of the synthesized ligand and some complexes against human breast cancer cell lines (MCF-7) and human hepatocarcinoma cell lines (HepG2) has been studied. The complexes (IC50 = 2.04-9.7, 2.5-3.7 μg/mL) showed potent antitumor activity comparable with their ligand (IC50 = 11.7, 3.45 μg/mL) against the above mentioned cell lines, respectively. The results evidently show that the activity of the ligand becomes more pronounced and significant when coordinated to the metal ion.

Coordination of manganous ion at the active site of pyruvate, phosphate dikinase: the complex of oxalate with the phosphorylated enzyme

International Nuclear Information System (INIS)

Kofron, J.L.; Ash, D.E.; Reed, G.H.

1988-01-01

Electron paramagnetic resonance spectroscopy has been used to investigate the structure of the complex of manganous ion with the phosphorylated form of pyruvate, phosphate dikinase (E/sub p/) and the inhibitor oxalate. Oxalate, an analogue of the enolate of pyruvate, is competitive with respect to pyruvate in binding to the phosphorylated form of the enzyme. Superhyperfine coupling between the unpaired electrons of Mn(I) and ligands specifically labeled with 17 O has been used to identify oxygen ligands to Mn(II) in the complex with oxalate and the phosphorylated form of the enzyme. Oxalate binds at the active site as a bidentate chelate with Mn(II). An oxygen from the 3'-N-phosphohistidyl residue of the protein is in the coordination sphere of Mn(II), and at least two water molecules are also bound to Mn(II) in the complex. Oxalate also binds directly to Mn(II) in a complex with nonphosphorylated enzyme. The structure for the E/sub p/-Mn(II)-oxalate complex implies that simultaneous coordination of a phospho group and of the attacking nucleophile to the divalent cation is likely an important factor in catalysis of this phospho-transfer reaction

Characterization of diatomite and its application for the retention of radiocobalt: role of environmental parameters.

Science.gov (United States)

Sheng, Guodong; Dong, Huaping; Li, Yimin

2012-11-01

Clay minerals have been extensively studied because of their strong sorption and complexation ability. In this work, diatomite was characterized by using acid-base titration. Retention of radionuclide (60)Co(II) from aqueous solution by sorption onto diatomite was investigated by using batch technique under various environmental conditions such as pH, ionic strength, humic acid (HA), fulvic acid (FA), and temperature. The results indicated that the sorption of Co(II) onto diatomite was strongly dependent on pH. At low pH value, the sorption of Co(II) was dominated by outer-sphere surface complexation and ion exchange with Na(+)/H(+) on diatomite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH value. The D-R model fitted the sorption isotherms better than the Langmuir and Freundlich models. The thermodynamic parameters (ΔH(0), ΔS(0) and ΔG(0)) calculated from the temperature-dependent sorption isotherms suggested that the sorption of Co(II) was an endothermic and spontaneous process. In addition, diatomite showed higher sorption capacity than that of lots of the sorbents reported in the literatures we surveyed. From the results of Co(II) removal by diatomite, the optimum reaction conditions can be obtained for the maximum removal of Co(II) from water. It is clear that the best pH values of the system to remove Co(II) from solution by using diatomite are 7-8. Considering the low cost and effective disposal of Co(II)-contaminated wastewaters, the best condition for Co(II) removal is at room temperature and solid content of 0.5 g/L. The results might be important for assessing the potential of practical application of diatomite in Co(II) and related radionuclide pollution management. Copyright © 2012 Elsevier Ltd. All rights reserved.

Methane Oxidation to Methanol Catalyzed by Cu-Oxo Clusters Stabilized in NU-1000 Metal-Organic Framework.

Science.gov (United States)

Ikuno, Takaaki; Zheng, Jian; Vjunov, Aleksei; Sanchez-Sanchez, Maricruz; Ortuño, Manuel A; Pahls, Dale R; Fulton, John L; Camaioni, Donald M; Li, Zhanyong; Ray, Debmalya; Mehdi, B Layla; Browning, Nigel D; Farha, Omar K; Hupp, Joseph T; Cramer, Christopher J; Gagliardi, Laura; Lercher, Johannes A

2017-08-02

Copper oxide clusters synthesized via atomic layer deposition on the nodes of the metal-organic framework (MOF) NU-1000 are active for oxidation of methane to methanol under mild reaction conditions. Analysis of chemical reactivity, in situ X-ray absorption spectroscopy, and density functional theory calculations are used to determine structure/activity relations in the Cu-NU-1000 catalytic system. The Cu-loaded MOF contained Cu-oxo clusters of a few Cu atoms. The Cu was present under ambient conditions as a mixture of ∼15% Cu + and ∼85% Cu 2+ . The oxidation of methane on Cu-NU-1000 was accompanied by the reduction of 9% of the Cu in the catalyst from Cu 2+ to Cu + . The products, methanol, dimethyl ether, and CO 2 , were desorbed with the passage of 10% water/He at 135 °C, giving a carbon selectivity for methane to methanol of 45-60%. Cu oxo clusters stabilized in NU-1000 provide an active, first generation MOF-based, selective methane oxidation catalyst.

Synthesis, spectral, thermal studies and electrical conductivity of Co (II) and Ni (II) complexes 3-[4-dimethylaminophenyl]-1-(2-pyridyl) prop-2-en-1-one (DMAPP)

Energy Technology Data Exchange (ETDEWEB)

Gaber, Mohamed, E-mail: abuelazm@yahoo.com [Chemistry Department, Faculty of Science, Tanta University, 31527 Tanta (Egypt); Al-Daly, Samy; Fayed, Tarek [Chemistry Department, Faculty of Science, Tanta University, 31527 Tanta (Egypt); El-Sayed, Yousif [Department of Chemistry, Faculty of Science, Tanta University, Tanta (Egypt)

2015-01-15

Co(II) and Ni(II) complexes of 3-[4-dimethylaminophenyl]-1-(2-pyridyl)prop-2-en-1-one have been prepared and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic spectra as well as thermal studies. The magnetic and spectral studies suggested the octahedral geometry for Co(II) and Ni(II) complexes. The kinetic parameters of the thermal decomposition stages have been evaluated using Coats–Redfern method. The electrical conductivity of the titled ligand and its Co(II) complexes was studied. The effects of different alcoholic solvents, pH and temperature on the complexation formation were considered. Also, the effect of Co(II) and Ni(II) ions on the emission spectrum of the free DMAPP was assigned. The stoichiometry of the metal complexes, the conditional formation constant, free energy, Beer{sup '}s law, molar extinction coefficient as well as specific absorptivity were evaluated. The ability of using the titled ligand as metalochromic indicator in complexometric titration was studied.

Tetrahalide complexes of the [U(NR)2]2+ ion: synthesis, theory, and chlorine K-edge X-ray absorption spectroscopy.

Science.gov (United States)

Spencer, Liam P; Yang, Ping; Minasian, Stefan G; Jilek, Robert E; Batista, Enrique R; Boland, Kevin S; Boncella, James M; Conradson, Steven D; Clark, David L; Hayton, Trevor W; Kozimor, Stosh A; Martin, Richard L; MacInnes, Molly M; Olson, Angela C; Scott, Brian L; Shuh, David K; Wilkerson, Marianne P

2013-02-13

Synthetic routes to salts containing uranium bis-imido tetrahalide anions [U(NR)(2)X(4)](2-) (X = Cl(-), Br(-)) and non-coordinating NEt(4)(+) and PPh(4)(+) countercations are reported. In general, these compounds can be prepared from U(NR)(2)I(2)(THF)(x) (x = 2 and R = (t)Bu, Ph; x = 3 and R = Me) upon addition of excess halide. In addition to providing stable coordination complexes with Cl(-), the [U(NMe)(2)](2+) cation also reacts with Br(-) to form stable [NEt(4)](2)[U(NMe)(2)Br(4)] complexes. These materials were used as a platform to compare electronic structure and bonding in [U(NR)(2)](2+) with [UO(2)](2+). Specifically, Cl K-edge X-ray absorption spectroscopy (XAS) and both ground-state and time-dependent hybrid density functional theory (DFT and TDDFT) were used to probe U-Cl bonding interactions in [PPh(4)](2)[U(N(t)Bu)(2)Cl(4)] and [PPh(4)](2)[UO(2)Cl(4)]. The DFT and XAS results show the total amount of Cl 3p character mixed with the U 5f orbitals was roughly 7-10% per U-Cl bond for both compounds, which shows that moving from oxo to imido has little effect on orbital mixing between the U 5f and equatorial Cl 3p orbitals. The results are presented in the context of recent Cl K-edge XAS and DFT studies on other hexavalent uranium chloride systems with fewer oxo or imido ligands.

Rare earth ions doped polyaniline/cobalt ferrite nanocomposites via a novel coordination-oxidative polymerization-hydrothermal route: Preparation and microwave-absorbing properties

Energy Technology Data Exchange (ETDEWEB)

Yang, Chunming; Jiang, Junjun; Liu, Xiaohua; Yin, Chengjie; Deng, Cuifen

2016-04-15

Polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} (RE=La, Ce, Y, x=0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca. 10–20 nm. Microwave absorption properties of polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa{sub x}Fe{sub 2−x}O{sub 4} nanocomposite, the optimal microwave absorption performance is at x=0.15, that is, the mass ratio of La in CoLa{sub x}Fe{sub 2−x}O{sub 4} is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. - Graphical abstract: Scheme PAn/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites prepared via a novel coordination-oxidative polymerization-hydrothermal route. - Highlights: • An organic–inorganic hybrid―polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} (RE=La, Ce, Y, x=0.05–0.25) nanocomposites was prepared via a novel coordination-oxidative polymerization-hydrothermal route. • The as-prepared polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites exhibit excellent microwave absorbing performance compared with the composites prepared by using conventional method. • The novel method reported in this work could

Rare earth ions doped polyaniline/cobalt ferrite nanocomposites via a novel coordination-oxidative polymerization-hydrothermal route: Preparation and microwave-absorbing properties

International Nuclear Information System (INIS)

Yang, Chunming; Jiang, Junjun; Liu, Xiaohua; Yin, Chengjie; Deng, Cuifen

2016-01-01

Polyaniline/CoRE_xFe_2_−_xO_4 (RE=La, Ce, Y, x=0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca. 10–20 nm. Microwave absorption properties of polyaniline/CoRE_xFe_2_−_xO_4 nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa_xFe_2_−_xO_4 nanocomposite, the optimal microwave absorption performance is at x=0.15, that is, the mass ratio of La in CoLa_xFe_2_−_xO_4 is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. - Graphical abstract: Scheme PAn/CoRE_xFe_2_−_xO_4 nanocomposites prepared via a novel coordination-oxidative polymerization-hydrothermal route. - Highlights: • An organic–inorganic hybrid―polyaniline/CoRE_xFe_2_−_xO_4 (RE=La, Ce, Y, x=0.05–0.25) nanocomposites was prepared via a novel coordination-oxidative polymerization-hydrothermal route. • The as-prepared polyaniline/CoRE_xFe_2_−_xO_4 nanocomposites exhibit excellent microwave absorbing performance compared with the composites prepared by using conventional method. • The novel method reported in this work could be employed to prepare other conductive polymers/inorganic nanocomposites as well.

Particle simulation in curvilinear coordinate systems

International Nuclear Information System (INIS)

LeBrun, M.J.; Tajima, T.

1989-01-01

We present methods for particle simulation of plasmas in a nearly arbitrary coordinate metric and describe a toroidal electrostatic simulation code that evolved from this effort. A Mercier-type coordinate system is used, with a nonuniform radial grid for improved cross-field resolution. A fast iterative method for solving the Poisson equation is employed, and the interpolation/filtering technique shown to be momentum and energy conserving in the continuum limit. Lorentz ion and drift electron species are used. The code has been thoroughly tested for its reproduction of linear and nonlinear physics, and has been applied to the toroidal drift wave problem and its impact on anomalous transport in tokamaks. 40 refs., 10 figs., 1 tab

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

The electrode parameters of Co(II) ion in hexagonal meso phase of the lyotropic liquid crystal ternary system (pluronic P84/cobalt/-xylene) is determined using cyclic voltammetry, deduced convolutive voltammetry and chronoamperometry techniques. The morphology of nanostructured deposited films of Co2+ ion in ...

Human and methodological sources of variability in the measurement of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine

DEFF Research Database (Denmark)

Barregard, Lars; Møller, Peter; Henriksen, Trine

2013-01-01

Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to as...

Extreme ultraviolet patterning of tin-oxo cages

Science.gov (United States)

Haitjema, Jarich; Zhang, Yu; Vockenhuber, Michaela; Kazazis, Dimitrios; Ekinci, Yasin; Brouwer, Albert M.

2017-07-01

We report on the extreme ultraviolet (EUV) patterning performance of tin-oxo cages. These cage molecules were already known to function as a negative tone photoresist for EUV radiation, but in this work, we significantly optimized their performance. Our results show that sensitivity and resolution are only meaningful photoresist parameters if the process conditions are optimized. We focus on contrast curves of the materials using large area EUV exposures and patterning of the cages using EUV interference lithography. It is shown that baking steps, such as postexposure baking, can significantly affect both the sensitivity and contrast in the open-frame experiments as well as the patterning experiments. A layer thickness increase reduced the necessary dose to induce a solubility change but decreased the patterning quality. The patterning experiments were affected by minor changes in processing conditions such as an increased rinsing time. In addition, we show that the anions of the cage can influence the sensitivity and quality of the patterning, probably through their effect on physical properties of the materials.

Ion-imprinted polymethacrylic microbeads as new sorbent for preconcentration and speciation of mercury.

Science.gov (United States)

Dakova, Ivanka; Karadjova, Irina; Georgieva, Ventsislava; Georgiev, George

2009-04-30

Metal ion-imprinted polymer particles have been prepared by copolymerization of methacrylic acid as monomer, trimethylolpropane trimethacrylate as cross-linking agent and 2,2'-azobisisobutyronitrile as initiator, in the presence of Hg(II)-1-(2-thiazolylazo)-2-naphthol complex. The separation and preconcentration characteristics of the Hg-ion-imprinted microbeads for inorganic mercury have been investigated by batch procedure. The optimal pH value for the quantitative sorption is 7. The adsorbed inorganic mercury is easily eluted by 2 mL 4M HNO(3). The adsorption capacity of the newly synthesized Hg ion-imprinted microbeads is 32.0 micromol g(-1) for dry copolymer. The selectivity of the copolymer toward inorganic mercury (Hg(II)) ion is confirmed through the comparison of the competitive adsorptions of Cd(II), Co(II), Cu(II), Ni(II), Pb(II), Zn(II)) and high values of the selectivity and distribution coefficients have been calculated. Experiments performed for selective determination of inorganic mercury in mineral and sea waters showed that the interfering matrix does not influence the extraction efficiency of Hg ion-imprinted microbeads. The detection limit for inorganic mercury is 0.006 microg L(-1) (3 sigma), determined by cold vapor atomic adsorption spectrometry. The relative standard deviation varied in the range 5-9 % at 0.02-1 microg L(-1) Hg levels. The new Hg-ion-imprinted microbeads have been tested and applied for the speciation of Hg in river and mineral waters: inorganic mercury has been determined selectively in nondigested sample, while total mercury e.g. sum of inorganic and methylmercury, has been determined in digested sample.

Heteroditopic receptors for ion-pair recognition.

Science.gov (United States)

McConnell, Anna J; Beer, Paul D

2012-05-21

Ion-pair recognition is a new field of research emerging from cation and anion coordination chemistry. Specific types of heteroditopic receptor designs for ion pairs and the complexity of ion-pair binding are discussed to illustrate key concepts such as cooperativity. The importance of this area of research is reflected by the wide variety of potential applications of ion-pair receptors, including applications as membrane transport and salt solubilization agents and sensors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gold nanoparticles modified with coordination compounds of metals: synthesis and application

International Nuclear Information System (INIS)

Beloglazkina, Elena K; Majouga, Alexander G; Romashkina, Renata B; Zyk, Nikolai V; Zefirov, Nikolai S

2012-01-01

The data on the preparation methods and applications of gold nanoparticles with coordinated metal ions on the surfaces are generalized. The currently available data on the interaction of metal ions with gold nanoparticles modified with organic (particularly, sulfur-containing) ligands comprising terminal chelating groups are considered in detail as well as the applications of such modified nanoparticles. The bibliography includes 141 references.

Minor Actinide Separations Using Ion Exchangers Or Ionic Liquids

International Nuclear Information System (INIS)

Hobbs, D.; Visser, A.; Bridges, N.

2011-01-01

This project seeks to determine if (1) inorganic-based ion exchange materials or (2) electrochemical methods in ionic liquids can be exploited to provide effective Am and Cm separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of inorganic-based ion-exchange materials for actinide and lanthanide ions. Furthermore, we seek to determine whether ionic liquids can serve as the electrolyte that would enable formation of higher oxidation states of Am and other actinides. Experiments indicated that pH, presence of complexants and Am oxidation state exhibit significant influence on the uptake of actinides and lanthanides by layered sodium titanate and hybrid zirconium and tin phosphonate ion exchangers. The affinity of the ion exchangers increased with increasing pH. Greater selectivity among Ln(III) ions with sodium titanate materials occurs at a pH close to the isoelectric potential of the ion exchanger. The addition of DTPA decreased uptake of Am and Ln, whereas the addition of TPEN generally increases uptake of Am and Ln ions by sodium titanate. Testing confirmed two different methods for producing Am(IV) by oxidation of Am(III) in ionic liquids (ILs). Experimental results suggest that the unique coordination environment of ionic liquids inhibits the direct electrochemical oxidation of Am(III). The non-coordinating environment increases the oxidation potential to a higher value, while making it difficult to remove the inner coordination of water. Both confirmed cases of Am(IV) were from the in-situ formation of strong chemical oxidizers.

Probing the coordination environment of Ti(3+) ions coordinated to nitrogen-containing Lewis bases.

Science.gov (United States)

Morra, E; Maurelli, S; Chiesa, M; Van Doorslaer, S

2015-08-28

Multi-frequency continuous-wave and pulsed EPR techniques are employed to investigate the coordination of nitrogen-containing ligands to Ti(3+)-chloro complexes. Frozen solutions of TiCl3 and TiCl3(Py)3 dissolved in nitrogen-containing solvents have been investigated together with the TiCl3(Py)3 solid-state complex. For these different systems, the hyperfine and nuclear quadrupole data of Ti(3+)-bound (14)N nuclei are reported and discussed in the light of DFT computations, allowing for a detailed description of the microscopic structure of these systems.

Mussel-inspired histidine-based transient network metal coordination hydrogels

Science.gov (United States)

Fullenkamp, Dominic E.; He, Lihong; Barrett, Devin G.; Burghardt, Wesley R.; Messersmith, Phillip B.

2013-01-01

Transient network hydrogels cross-linked through histidine-divalent cation coordination bonds were studied by conventional rheologic methods using histidine-modified star poly(ethylene glycol) (PEG) polymers. These materials were inspired by the mussel, which is thought to use histidine-metal coordination bonds to impart self-healing properties in the mussel byssal thread. Hydrogel viscoelastic mechanical properties were studied as a function of metal, pH, concentration, and ionic strength. The equilibrium metal-binding constants were determined by dilute solution potentiometric titration of monofunctional histidine-modified methoxy-PEG and were found to be consistent with binding constants of small molecule analogs previously studied. pH-dependent speciation curves were then calculated using the equilibrium constants determined by potentiometric titration, providing insight into the pH dependence of histidine-metal ion coordination and guiding the design of metal coordination hydrogels. Gel relaxation dynamics were found to be uncorrelated with the equilibrium constants measured, but were correlated to the expected coordination bond dissociation rate constants. PMID:23441102

Novel Mechanism of Fatty Acid Sensing in Enteroendocrine Cells: Specific Structures in Oxo-Fatty Acids Produced by Gut Bacteria are Responsible for CCK Secretion in STC-1 Cells via GPR40.

Science.gov (United States)

Hira, Tohru; Ogasawara, Shono; Yahagi, Asuka; Kamachi, Minami; Li, Jiaxin; Nishimura, Saki; Sakaino, Masayoshi; Yamashita, Takatoshi; Kishino, Shigenobu; Ogawa, Jun; Hara, Hiroshi

2018-06-25

The secretion of gut hormones, such as cholecystokinin (CCK) is stimulated by fatty acids. Although a chain length-dependent mechanism has been proposed, other structural relationships to releasing activity remain unclear. We aimed to elucidate specific structures in fatty acids that are responsible for their CCK-releasing activity, and related sensing mechanisms in enteroendocrine cells. We examined CCK secretory activities in a murine CCK-producing cell line STC-1 by exposing the cells to various modified fatty acids produced by gut lactic acid bacteria. The effects of fatty acids on gastric emptying rate as a CCK-mediated function were examined using acetaminophen- and phenol red-methods in rats. Out of more than thirty octadecanoic (C18)-derived fatty acids tested, five oxo-fatty acids potently stimulated CCK secretion without cytotoxic effects in STC-1 cells. Three fatty acids had a distinct specific structure containing one double-bond, whereas the other two had two double-bonds, nearby an oxo residue. CCK secretion induced by representative fatty acids (10-oxo-trans-11-18:1 and 13-oxo-cis-9,cis-15-18:2) was attenuated by a fatty acid-receptor GPR40 antagonist. Oral administration of 13-oxo-cis-9,cis-15-18:2 lowered the gastric emptying rate in rats in a dose- and structure-dependent manner. These results revealed a novel fatty acid-sensing mechanism in enteroendocrine cells. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hydrothermal synthesis and characterization of a binuclear complex and a coordination

Directory of Open Access Journals (Sweden)

Reza Mohamadinasab

2010-06-01

Full Text Available Two new copper complexes [(bipy(pydcCu(μ-OCO-pydcCu(bipy(H2O].3.5H¬2O (1 and {[(μ2-C2O4(2,2'-bipyCu].2H2O}n (2 (pydcH2 = pyridine-2,6-dicarboxylilic acid, bipy = 2,2'-bipyridine have been hydrothermally synthesized. Both complexes were characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction studies. Complex 1 consists of two independent neutral molecules. In every moiety, metal ion center is in a distorted octahedral geometry. Coordination polymer (2 has been prepared from the reaction of bis-(cyclohexanone-oxal-dihydrazone,2,2'-bipyridine and Cu(NO32 in basic solution and under hydrothermal condition. The results showed that the bis-(cyclohexanone-oxal-dihydrazone was converted to oxalate ion under heating and basic pH. Each metal ion center in 2 is in a distorted octahedral geometry and is coordinated by four oxygen atoms of two bridged oxalate ions and two nitrogen atoms of 2,2'-bipyridine molecules. In the crystal structure of 2, some H-bonds and π-π interaction cause formation of a 3D network.

Laser-ignited frontal polymerization of shape-controllable poly(VI-co-AM) hydrogels based on 3D templates toward adsorption of heavy metal ions

Science.gov (United States)

Fan, Suzhen; Liu, Sisi; Wang, Xiao-Qiao; Wang, Cai-Feng; Chen, Su

2016-06-01

Given the increasing heavy metal pollution issue, fast preparation of polymeric hydrogels with excellent adsorption property toward heavy metal ions is very attractive. In this work, a series of poly( N-vinylimidazole-co-acrylamide) (poly(VI-co-AM)) hydrogels were synthesized via laser-ignited frontal polymerization (LIFP) for the first time. The dependence of frontal velocity and temperature on two factors monomer ratios and initiator concentrations was systematically investigated. Poly(VI-co-AM) hydrogels with any self-supporting shapes can be synthesized by a one-step LIFP in seconds through the application of 3D templates. These shape-persistent hydrogels are pH-responsive and exhibit excellent adsorption/desorption characteristics toward Mn(II), Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) ions, and the adsorption conformed to the pseudo-second-order kinetic model. The reusability of the hydrogels toward mental ions adsorption was further researched, which suggested that the hydrogels can be reused without serious decrease in adsorption capacity. This work might open a promising strategy to facilely prepare shape-controllable hydrogels and expand the application of LIFP.

Iminodiacetic acid functionalised organopolymer monoliths: application to the separation of metal cations by capillary high-performance chelation ion chromatography.

Science.gov (United States)

Moyna, Áine; Connolly, Damian; Nesterenko, Ekaterina; Nesterenko, Pavel N; Paull, Brett

2013-03-01

Lauryl methacrylate-co-ethylene dimethacrylate monoliths were polymerised within fused silica capillaries and subsequently photo-grafted with varying amounts of glycidyl methacrylate (GMA). The grafted monoliths were then further modified with iminodiacetic acid (IDA), resulting in a range of chelating ion-exchange monoliths of increasing capacity. The IDA functional groups were attached via ring opening of the epoxy group on the poly(GMA) structure. Increasing the amount of attached poly(GMA), via photo-grafting with increasing concentrations of GMA, from 15 to 35%, resulted in a proportional and controlled increase in the complexation capacity of the chelating monoliths. Scanning capacitively coupled contactless conductivity detection (sC(4)D) was used to characterise and verify homogenous distribution of the chelating ligand along the length of the capillaries non-invasively. Chelation ion chromatographic separations of selected transition and heavy metals were carried out, with retention factor data proportional to the concentration of grafted poly(GMA). Average peak efficiencies of close to 5,000 N/m were achieved, with the isocratic separation of Na, Mg(II), Mn(II), Co(II), Cd(II) and Zn(II) possible on a 250-mm-long monolith. Multiple monolithic columns produced to the same recipes gave RSD data for retention factors of ions). The monolithic chelating ion-exchanger was applied to the separation of alkaline earth and transition metal ions spiked in natural and potable waters.

(E-3-Methyl-6-(3-oxo-3-(thiophen-2-yl-1-propenyl-2(3H-benzothiazolone

Directory of Open Access Journals (Sweden)

Yordanka Ivanova

2016-04-01

Full Text Available The title compound, (E-3-methyl-6-(3-oxo-3-(thiophen-2-yl-1-propenyl-2(3H-benzothiazolone, was synthesized by Claisen-Schmidt condensation of 3-methyl-2(3H-benzothiazolone-6-carbaldehyde with 2-acetylthiophene in 94% yield. The structure of the target compound was confirmed using 1H-NMR, 13C-NMR, IR, MS, and elemental analysis.

Solar-Pumping Upconversion of Interfacial Coordination Nanoparticles.

Science.gov (United States)

Ishii, Ayumi; Hasegawa, Miki

2017-01-30

An interfacial coordination nanoparticle successfully exhibited an upconversion blue emission excited by very low-power light irradiation, such as sunlight. The interfacial complex was composed of Yb ions and indigo dye, which formed a nano-ordered thin shell layer on a Tm 2 O 3 nanoparticle. At the surface of the Tm 2 O 3 particle, the indigo dye can be excited by non-laser excitation at 640 nm, following the intramolecular energy transfer from the indigo dye to the Yb ions. Additionally, the excitation energy of the Yb ion was upconverted to the blue emission of the Tm ion at 475 nm. This upconversion blue emission was achieved by excitation with a CW Xe lamp at an excitation power of 0.14 mW/cm 2 , which is significantly lower than the solar irradiation power of 1.4 mW/cm 2 at 640 ± 5 nm.

Mechanism of Oxidation of Ethane to Ethanol at Iron(IV)-Oxo Sites in Magnesium-Diluted Fe2(dobdc).

Science.gov (United States)

Verma, Pragya; Vogiatzis, Konstantinos D; Planas, Nora; Borycz, Joshua; Xiao, Dianne J; Long, Jeffrey R; Gagliardi, Laura; Truhlar, Donald G

2015-05-06

The catalytic properties of the metal-organic framework Fe2(dobdc), containing open Fe(II) sites, include hydroxylation of phenol by pure Fe2(dobdc) and hydroxylation of ethane by its magnesium-diluted analogue, Fe0.1Mg1.9(dobdc). In earlier work, the latter reaction was proposed to occur through a redox mechanism involving the generation of an iron(IV)-oxo species, which is an intermediate that is also observed or postulated (depending on the case) in some heme and nonheme enzymes and their model complexes. In the present work, we present a detailed mechanism by which the catalytic material, Fe0.1Mg1.9(dobdc), activates the strong C-H bonds of ethane. Kohn-Sham density functional and multireference wave function calculations have been performed to characterize the electronic structure of key species. We show that the catalytic nonheme-Fe hydroxylation of the strong C-H bond of ethane proceeds by a quintet single-state σ-attack pathway after the formation of highly reactive iron-oxo intermediate. The mechanistic pathway involves three key transition states, with the highest activation barrier for the transfer of oxygen from N2O to the Fe(II) center. The uncatalyzed reaction, where nitrous oxide directly oxidizes ethane to ethanol is found to have an activation barrier of 280 kJ/mol, in contrast to 82 kJ/mol for the slowest step in the iron(IV)-oxo catalytic mechanism. The energetics of the C-H bond activation steps of ethane and methane are also compared. Dehydrogenation and dissociation pathways that can compete with the formation of ethanol were shown to involve higher barriers than the hydroxylation pathway.

Structural, spectral and biological studies of binuclear tetradentate metal complexes of N 3O Schiff base ligand synthesized from 4,6-diacetylresorcinol and diethylenetriamine

Science.gov (United States)

Emara, Adel A. A.

2010-09-01

The binuclear Schiff base, H 2L, ligand was synthesized by reaction of 4,6-diacetylresorcinol with diethylenetriamine in the molar ratio 1:2. The coordination behavior of the H 2L towards Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cr(III), VO(IV) and UO 2(VI) ions has been investigated. The elemental analyses, magnetic moments, thermal studies and IR, electronic, 1H NMR, ESR and mass spectra were used to characterize the isolated ligand and its metal complexes. The ligand acts as dibasic with two N 3O-tetradentate sites and can coordinate with two metal ions to form binuclear complexes. The bonding sites are the nitrogen atoms of the azomethine and amine groups and the oxygen atoms of the phenolic groups. The metal complexes exhibit either square planar, tetrahedral, square pyramid or octahedral structures. The Schiff base ligand and its metal complexes were tested against four pathogenic bacteria ( Staphylococcus aureus and Streptococcus pyogenes) as Gram-positive bacteria, and ( Pseudomonas fluorescens and Pseudomonas phaseolicola) as Gram-negative bacteria and two pathogenic fungi ( Fusarium oxysporum and Aspergillus fumigatus) to assess their antimicrobial properties. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

Visible Light Absorption of Binuclear TiOCoII Charge-Transfer UnitAssembled in Mesoporous Silica

Energy Technology Data Exchange (ETDEWEB)

Han, Hongxian; Frei, Heinz

2007-01-30

Grafting of CoII(NCCH3)2Cl2 onto mesoporous Ti-MCM-41 silicain acetonitrile solution affords binuclear Ti-O-CoII sites on the poresurface under complete replacement of the precursor ligands byinteractions with anchored Ti centers and the silica surface. The CoIIligand field spectrum signals that the Co centers are anchored on thepore surface in tetrahedral coordination. FT-infrared action spectroscopyusing ammonia gas adsorption reveals Co-O-Si bond modes at 831 and 762cm-1. No Co oxide clusters are observed in the as-synthesized material.The bimetallic moieties feature an absorption extending from the UV intothe visible to about 600 nm which is attributed to the TiIV-O-CoII?3TiIII-O-CoIII metal-to-metal charge-transfer (MMCT) transition. Thechromophore is absent in MCM-41 containing Ti and Co centers isolatedfrom each other; this material was synthesized by grafting CoII onto aTi-MCM-41 sample with the Ti centers protected by a cyclopentadienylligand. The result indicates that the appearance of the charge-transferabsorption requires that the metal centers are linked by an oxo bridge,which is additionally supported by XANES spectroscopy. The MMCTchromophore of Ti-O-CoII units has sufficient oxidation power to serve asvisible light electron pump for driving multi-electron transfer catalystsof demanding uphill reactions such as water oxidation.

Poly[[[diisothiocyanatocobalt(II]-bis[μ-4-tert-butyl-2,6-bis(1,2,4-triazol-1-ylmethylphenol

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available In the title compound, {[Co(NCS2(C16H20N6O2]·2C3H7NO·2H2O}n, each CoII ion located on an inversion center is six-coordinated by four equatorial N atoms from four different 4-tert-butyl-2,6-bis(1,2,4-triazol-1-ylmethylphenol (L ligands, and by two N atoms from two axial thiocyanate anions [Co—N = 2.104 (3–2.144 (3 Å]. The metal centres are connected via the bidentate L ligands into two-dimensional polymeric layers parallel to bc plane. The dimethylformamide and solvent water molecules participate in intermolecular O—H...O and O—H...S hydrogen bonds, which consolidate the crystal packing.

Six-Coordinate Ln(III Complexes with Various Coordination Geometries Showing Distinct Magnetic Properties

Directory of Open Access Journals (Sweden)

Mei Guo

2018-01-01

Full Text Available The syntheses, structural characterization, and magnetic properties of three lanthanide complexes with formulas [Ln(L13] (Ln = Dy (1Dy; Er (1Er; and [Dy(L22] (2Dy were reported. Complexes 1Dy and 1Er are isostructural with the metal ion in distorted trigonal-prismatic coordination geometry, but exhibit distinct magnetic properties due to the different shapes of electron density for DyIII (oblate and ErIII (prolate ions. Complex 1Dy shows obvious SMM behavior under a zero direct current (dc field with an effective energy barrier of 31.4 K, while complex 1Er only features SMM behavior under a 400 Oe external field with an effective energy barrier of 23.96 K. In stark contrast, complex 2Dy with the octahedral geometry only exhibits the frequency dependence of alternating current (ac susceptibility signals without χ″ peaks under a zero dc field.

Luminescent, magnetic and ferroelectric properties of noncentrosymmetric chain-like complexes composed of nine-coordinate lanthanide ions.

Science.gov (United States)

Li, Xi-Li; Chen, Chun-Lai; Xiao, Hong-Ping; Wang, Ai-Ling; Liu, Cai-Ming; Zheng, Xianjun; Gao, Li-Jun; Yang, Xiao-Gang; Fang, Shao-Ming

2013-11-21

Reaction of the chiral ligand (-)-4,5-pinenepyridyl-2-pyrazine (L) with Ln(hfac)3·2H2O precursors [hfac(-) = 1,1,1,5,5,5-hexafluoroacetylacetonate, Ln = Sm(3+) (1), Eu(3+) (2), Tb(3+) (3) and Dy(3+) (4)] in methanol solution led to the formation of four noncentrosymmetric lanthanide complexes with the general formula [Ln(hfac)3L]n·H2O. The single-crystal X-ray diffraction analyses revealed that they are isostructural and take a one-dimensional (1D) chain structure based on the Ln(hfac)3L repeating units, in which the nine-coordinate Ln(3+) ions reside in a tricapped trigonal prism (TTP) environment never reported in previous 1D chain lanthanide complexes. The investigations of their photophysical properties showed that complexes 1, and 3 exhibit characteristic emissions of Sm(3+), Eu(3+) and Tb(3+) ions with respective luminescent lifetime values of 0.065, 1.066 and 0.129 ms, while complex 4 does not display any emission. The different luminescent intensities and lifetimes among them were further discussed in detail. Moreover, the magnetic properties of complexes 1-4 were assessed with a special emphasis on the Dy(3+) complex 4. Alternating-current (ac) magnetic susceptibility measurements indicated that field-induced two-step slow magnetic relaxation processes were observed in 4, indicating the single-molecule magnet (SMM) behavior of 4. In addition, the noncentrosymmetric complexes 1-4 crystallizing in the same polar point group (Cs) exhibit both ferroelectric and nonlinear optical properties at room temperature. All these features make them multifunctional crystalline molecule materials.

Na Cl ion pair association in water-DMSO mixtures: Effect of ion pair ...

Indian Academy of Sciences (India)

The 12-6-1 potential model predicts running coordination numbers closest to experimental data. Keywords. ... value of interaction energy minimum between the Na. + and Cl. − ..... ion pair mostly remains as a CIP, a fair amount of SAIP is also ...

Metal-oxo containing polymer nanobeads as potential contrast agents for magnetic resonance imaging

Science.gov (United States)

Pablico, Michele Huelar

Magnetic resonance imaging (MRI) has greatly revolutionized the way diseases are detected and treated, as it is a non-invasive imaging modality solely based on the interaction of radiowaves and hydrogen nuclei in the presence of an external magnetic field. It is widely used today for the diagnosis of diseases as it offers an efficient method of mapping structure and function of soft tissues in the body. Most MRI examinations utilize paramagnetic materials known as contrast agents, which enhance the MR signal by decreasing the longitudinal (T1) and transverse (T2) relaxation times of the surrounding water protons in biological systems. This results into increased signal intensity differences thereby allowing better interpretation and analysis of pathological tissues. Contrast agents function by lowering the T1 or lowering the T2, resulting into bright and dark contrasts, respectively. The most common MRI contrast agents that are in clinical use today are gadolinium chelates and superparamagnetic iron oxide nanoparticles, both of which have their own advantages in terms of contrast enhancement properties. In the past few years, however, there has been interest in utilizing metal-containing clusters for MRI contrast enhancement as these materials bridge the gap between the constrained structure and magnetic properties of the gadolinium chelates with the superparamagnetic behavior of the iron oxide nanoparticles. Recently, metallic clusters containing Mn and Fe metal centers have received increased attention mainly because of their potential for high spin states and benign nature. In the quest to further develop novel imaging agents, this research has focused on investigating the use of metal-oxo clusters as potential contrast agents for MRI. The primary goal of this project is to identify clusters that meet the following criteria: high paramagnetic susceptibility, water-soluble, stable, cheap, contain environmentally benign metals, and easily derivatized. This work is

Polynuclear Iron-Oxo/Hydroxy Complexes of Ketoacidoximate Ligands: Synthesis, Structures and Conversion to Ferric Oxide

KAUST Repository

Davaasuren, Bambar; Khanderi, Jayaprakash; Rothenberger, Alexander

2017-01-01

The polynuclear iron-oxo/hydroxy complexes containing ketoacidoximate ligands described in this report are [Fe3(μ3-O){O2C-C(C6H5)=NOCH3}6(py)3] (1) (py=pyridine), [Fe2(μ3-O){O2C-C(CH2-C6H5)=NO}2(H2O)(CH3OH)]2 (2) and [{Fe(μ2-OH)(O2C-C(CH3)=NO

Oxidation of ethane to ethanol by N2O in a metal-organic framework with coordinatively unsaturated iron(II) sites.

Science.gov (United States)

Xiao, Dianne J; Bloch, Eric D; Mason, Jarad A; Queen, Wendy L; Hudson, Matthew R; Planas, Nora; Borycz, Joshua; Dzubak, Allison L; Verma, Pragya; Lee, Kyuho; Bonino, Francesca; Crocellà, Valentina; Yano, Junko; Bordiga, Silvia; Truhlar, Donald G; Gagliardi, Laura; Brown, Craig M; Long, Jeffrey R

2014-07-01

Enzymatic haem and non-haem high-valent iron-oxo species are known to activate strong C-H bonds, yet duplicating this reactivity in a synthetic system remains a formidable challenge. Although instability of the terminal iron-oxo moiety is perhaps the foremost obstacle, steric and electronic factors also limit the activity of previously reported mononuclear iron(IV)-oxo compounds. In particular, although nature's non-haem iron(IV)-oxo compounds possess high-spin S = 2 ground states, this electronic configuration has proved difficult to achieve in a molecular species. These challenges may be mitigated within metal-organic frameworks that feature site-isolated iron centres in a constrained, weak-field ligand environment. Here, we show that the metal-organic framework Fe2(dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate) and its magnesium-diluted analogue, Fe0.1Mg1.9(dobdc), are able to activate the C-H bonds of ethane and convert it into ethanol and acetaldehyde using nitrous oxide as the terminal oxidant. Electronic structure calculations indicate that the active oxidant is likely to be a high-spin S = 2 iron(IV)-oxo species.

Exploring 3D non-interpenetrated metal-organic framework with malonate-bridged Co(II) coordination polymer: structural elucidation and theoretical study

Science.gov (United States)

Hossain, Anowar; Mandal, Tripti; Mitra, Monojit; Manna, Prankrishna; Bauzá, Antonio; Frontera, Antonio; Seth, Saikat Kumar; Mukhopadhyay, Subrata

2017-12-01

A Co(II)-based coordination polymer with tetranuclear cobalt(II)-malonate cluster has been easily generated by aqueous medium self-assembly from Cobalt(II) chloride hexahydrate and malonic acid. The structure exhibits a non-interpenetrating, highly undulating two-dimensional (2D) bi-layer network with (4,4) topology. The crystal structure is composed of infinite interdigitated 2D metal-organic bi-layers which extended to an intricate 3D framework through the interbilayer hydrogen bonds. We have studied energetically by means of Density Functional Theory (DFT) calculations the H-bonding interactions that connect the 2D metal-organic bi-layers. The finite theoretical models have been used to compute conventional O‒H•••O and unconventional C‒H•••O interactions which plays a key role to build 3D architecture.

Synthesis of 3 alpha-deuterated 7 alpha-hydroxy-DHEA and 7-oxo-DHEA and application in LC-MS/MS plasma analysis

Czech Academy of Sciences Publication Activity Database

Sosvorova, L.K.; Sarek, J.; Vitku, J.; Kvasnica, Miroslav

2016-01-01

Roč. 112, AUG (2016), s. 88-94 ISSN 0039-128X Institutional support: RVO:61389030 Keywords : 7 alpha-Hydroxy-DHEA * 7-Oxo-DHEA * Deuterated standard Subject RIV: CE - Biochemistry Impact factor: 2.282, year: 2016

Ethyl (1R*,10S*,12R*,15S*-4-Hydroxy-2-oxo-15- (2-oxo-1-pyrrolidinyl-9-oxatetracyclo[10.2.2.01,10.03,8]hexadeca-3,5,7,13-tetraene-13-carboxylate

Directory of Open Access Journals (Sweden)

Jorge Heredia-Moya

2017-01-01

Full Text Available N-Vinylpirrolidinone reacts with (E-ethyl 5-hydroxy-3-(4-oxo-4H-chromen-3-yl acrylate (1 through a domino reaction similar to that reported reaction for ethyl vinyl ether. Inverse electron demand Diels–Alder (IEDDA–elimination-IEDDA generates isomeric tetracycles 5 and 6. The assignment of the relative stereochemistry of the products was made by comparing the proton couplings with those obtained by reaction with ethyl vinyl ether.

Cu(II) and Co(II) complexes of benzimidazole derivative: Structures, catecholase like activities and interaction studies with hydrogen peroxide

Science.gov (United States)

Kumari, Babli; Adhikari, Sangita; Matalobos, Jesús Sanmartín; Das, Debasis

2018-01-01

Present study describes the synthesis and single crystal X-ray structures of two metal complexes of benzimidazole derivative (PBI), viz. the Cu(II) complex, [Cu(PBI)2(NCS)]ClO4 (1) and a Co(II) complex, [Co(PBI)2(NCS)1.75Cl0.25] (2). The Cu(II) complex (1) shows catecholase like activity having Kcat = 1.84 × 104 h-1. Moreover, interactions of the complexes with hydrogen peroxide have been investigated using fluorescence spectroscopy. The interaction constant of 1 and 2 for H2O2 are 6.67 × 102 M-1 and 1.049 × 103 M-1 while their detection limits for H2O2 are 3.37 × 10-7 M and 2.46 × 10-7 M respectively.

Moessbauer effect study of oxidation and coordination states of iron in some sodium borate glasse:;

International Nuclear Information System (INIS)

Eissa, N.A.; Sanad, A.M.; Youssef, S.M.; El-Henawii, S.A.; Gomaa, S.Sh.; Mostafa, A.G.

1980-01-01

A structural study of some sodium borate glasses containing iron was carried out applying ME spectroscopy. Both oxidation and coordination states of iron were investigated under the effect of gradual replacing of sodium carbonate by sodium nitrate in the glass batches. The glasses were melted in porcelain crucibles using an electrically heated furnace at 1000+-10 deg C, then were quenched on a steel plate at room temperature (R.T.). The ME source was 20 mCi radioactive Co-57 in chromium. The obtained ME spectra indicated that at lower sodium nitrate content both Fe 2+ and Fe 3+ are present in these glasses. At moderate concentrations some Fe 3+ ions were separated in a crystalline phase and the rest of the iron ions appeared as ferric ions in glassy state. At high sodium nitrate content only Fe 3+ ions in glassy state were detected. The values of the ME parameters for all iron ions indicated that all of them are in the octahedral coordination state. The density measurements confirm the separation of a crystalline phase at moderate sodium nitrate content. (author)

Surrey Ion Beam Centre: the EPSRC MRF for ion beam applications - 01002

International Nuclear Information System (INIS)

Webb, R.P.

2016-01-01

The SIBC (Surrey Ion Beam Centre) is an element of the Virtual Ion Beam Centre that coordinates 3 U.K. experimental facilities: SIBC (University of Surrey) for implantation and ion beam applications, Miami and MEIS facility (University of Huddersfield) and gamma ray and neutron irradiation emulation facility (University of Manchester). The SIBC works actively with industry, developing bespoke processes and services, particularly for the photonics industry and provides ion beam facilities to about 20 companies across the world. It operates a stringent quality control program and is one of the few ion beam laboratories in the world to operate under ISO 9001 certification. The equipment of SIBC is presented and some applications of ion beam analysis concerning the identification of gunshot residues, the determination of the origin of a painting, the analysis of proteins are described. Different techniques such as PIXE (Particle Induced X-ray Emission), RBS (Rutherford Backscattering Spectroscopy), NRA (Nuclear Reaction Analysis), SIMS (Secondary Ion Mass Spectrometry) are also explained in the slides of the presentation that have been added at the end of the paper

LC-mS analysis of human urine specimens for 2-oxo-3-hydroxy LSD: method validation for potential interferants and stability study of 2-oxo-3-hydroxy LSD under various storage conditions.

Science.gov (United States)

Klette, Kevin L; Horn, Carl K; Stout, Peter R; Anderson, Cynthia J

2002-01-01

2-Oxo-3-hydroxy lysergic acid diethylamide (O-H-LSD), a major LSD metabolite, has previously been demonstrated to be a superior marker for identifying LSD use compared with the parent drug, LSD. Specifically, O-H-LSD analyzed using liquid chromatography-mass spectrometry has been reported to be present in urine at concentrations 16 to 43 times greater than LSD. To further support forensic application of this procedure, the specificity of the assay was assessed using compounds that have structural and chemical properties similar to O-H-LSD, common over-the-counter products, prescription drugs and some of their metabolites, and other drugs of abuse. Of the wide range of compounds studied, none were found to interfere with the detection of O-H-LSD or the internal standard 2-oxo-3-hydroxy lysergic acid methyl propylamide. The stability of O-H-LSD was investigated from 0 to 9 days at various temperatures, pH conditions, and exposures to fluorescent light. Additionally, the effect of long-term frozen storage and pH was investigated from 0 to 60 days. There was no significant loss of O-H-LSD under both refrigerated and frozen conditions within the normal human physiological pH range of urine (4.6-8.4). However, significant loss of O-H-LSD was observed in samples prepared at pH 4.6-8.4 and stored at room temperature or higher (24-50 degrees C).

Compatibility of nitrilotriacetic acid and 3-acetyl-4-hydroxy-6-methyl-2-pyrone in the coordination sphere of lanthanon ions

International Nuclear Information System (INIS)

Kadian, R.K.; Garg, B.S.; Singh, R.P.

1982-01-01

A study of the competetion of 3-acetyl-4-hydroxy-6-methyl-2-pyrone (dehydracetic acid, DHA) and nitrilotriacetic acid (NTA) in the coordination sphere of lanthanon ions has been carried out by calculating reproportionation constant which relates the stability of the mixed ligand complex to those of the parent complexes formed by the same ligands. It has been found that NTA and DHA are incompatible ligands and mixed ligand complexes formed are less stable than either of the parent complexes. The fact is also supported by the observed change in free energy occuring during mixed ligand complex formation. All these studies have been carried out at 30.0 +- 0.5 0 and μ-0.01 (NaClO 4 ) in 50 percent v/v aqueous dioxane medium. (author)

Reviving Lonidamine and 6-Diazo-5-oxo-L-norleucine to Be Used in Combination for Metabolic Cancer Therapy

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Diana Cervantes-Madrid

2015-01-01

Full Text Available Abnormal metabolism is another cancer hallmark. The two most characterized altered metabolic pathways are high rates of glycolysis and glutaminolysis, which are natural targets for cancer therapy. Currently, a number of newer compounds to block glycolysis and glutaminolysis are being developed; nevertheless, lonidamine and 6-diazo-5-oxo-L-norleucine (DON are two old drugs well characterized as inhibitors of glycolysis and glutaminolysis, respectively, whose clinical development was abandoned years ago when the importance of cancer metabolism was not fully appreciated and clinical trial methodology was less developed. In this review, a PubMed search using the words lonidamine and 6-diazo-5-oxo-L-norleucine (DON was undertaken to analyse existing information on the preclinical and clinical studies of these drugs for cancer treatment. Data show that they exhibit antitumor effects; besides there is also the suggestion that they are synergistic. We conclude that lonidamine and DON are safe and potentially effective drugs that need to be reevaluated in combination as metabolic therapy of cancer.

Reviving Lonidamine and 6-Diazo-5-oxo-L-norleucine to Be Used in Combination for Metabolic Cancer Therapy

Science.gov (United States)

Cervantes-Madrid, Diana; Romero, Yair; Dueñas-González, Alfonso

2015-01-01

Abnormal metabolism is another cancer hallmark. The two most characterized altered metabolic pathways are high rates of glycolysis and glutaminolysis, which are natural targets for cancer therapy. Currently, a number of newer compounds to block glycolysis and glutaminolysis are being developed; nevertheless, lonidamine and 6-diazo-5-oxo-L-norleucine (DON) are two old drugs well characterized as inhibitors of glycolysis and glutaminolysis, respectively, whose clinical development was abandoned years ago when the importance of cancer metabolism was not fully appreciated and clinical trial methodology was less developed. In this review, a PubMed search using the words lonidamine and 6-diazo-5-oxo-L-norleucine (DON) was undertaken to analyse existing information on the preclinical and clinical studies of these drugs for cancer treatment. Data show that they exhibit antitumor effects; besides there is also the suggestion that they are synergistic. We conclude that lonidamine and DON are safe and potentially effective drugs that need to be reevaluated in combination as metabolic therapy of cancer. PMID:26425550

Complexation-induced supramolecular assembly drives metal-ion extraction.

Science.gov (United States)

Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

2014-09-26