Sample records for ru3oac6 py2 dicnpy

  1. Continuous degradation of trichloroethylene by Xanthobacter sp. strain Py2 during growth on propene.

    Reij, M.W.; Kieboom, J.; de Bont, J A; Hartmans, S


    Propene-grown Xanthobacter sp. strain Py2 cells can degrade trichloroethylene (TCE), but the transformation capacity of such cells was limited and depended on both the TCE concentration and the biomass concentration. Toxic metabolites presumably accumulated extracellularly, because the fermentation of glucose by yeast cells was inhibited by TCE degradation products formed by strain Py2. The affinity of the propene monooxygenase for TCE was low, and this allowed strain Py2 to grow on propene i...

  2. On the diuphantine equation χ3 + 1 = py2%关于丢番图方程x3±1=py2

    牟善志; 戴习民


    应用因子分解法、简单同余法以及前人的已知结果证明了:(1)设P是1个奇素数,则丢番图方程组x+1=3py2,x-x+1=3y22,(y1,y2)=1,y1>0,y2>0,无正整数解x,P,y1,y2;(2)丢番图方程x3+1=py2(其中P≡-1(rood 3)为素数)仅有整数解(x,y)=(-1,0);(3)丢番图方程χ3-1=py2(其中P≡1(mod 3)为素数)仅有整数解(x,Y)=(1,0).

  3. Spectroscopic, Electrochemical and Computational Characterisation of Ru Species Involved in Catalytic Water Oxidation: Evidence for a [RuV(O)(Py2Metacn)] Intermediate

    Casadevall, Carla; Codolà Duch, Zoel; Costas Salgueiro, Miquel; Lloret Fillol, Julio


    A new family of ruthenium complexes based on the N-pentadentate ligand Py2Metacn (N-methyl-N′,N′′-bis(2-picolyl)-1,4,7-triazacyclononane) has been synthesised and its catalytic activity has been studied in the water-oxidation (WO) reaction. We have used chemical oxidants (ceric ammonium nitrate and NaIO4) to generate the WO intermediates [RuII(OH2)(Py2Metacn)]2+, [RuIII(OH2)(Py2Metacn)]3+, [RuIII(OH)(Py2Metacn)]2+ and [RuIV(O)(Py2Metacn)]2+, which have been characterised spectroscopically. Th...

  4. Oxygen binding and activation by the complexes of PY2- and TPA-appended diphenylglycoluril receptors with copper and other metals

    Sprakel, VSI; Feiters, MC; Klaucke, WM; Klopstra, M; Brinksma, J; Feringa, BL; Karlin, KD; Nolte, RJM; Sprakel, Vera S.I.; Feiters, Martin C.; Meyer-Klaucke, Wolfram; Karlin, Kenneth D.; Nolte, Roeland J.M.; Feringa, Bernard


    The copper( I) complexes of diphenylglycoluril basket receptors 1 and 2, appended with bis(2-ethylpyridine) amine (PY2) and tris(2-methylpyridine) amine (TPA), respectively, and their dioxygen adducts were studied with low-temperature UV-vis and X-ray absorption spectroscopy (XAS). The copper(I) com

  5. Dinuclear cobalt(II) and copper(II) complexes with a Py2N4S2 macrocyclic ligand.

    Núñez, Cristina; Bastida, Rufina; Lezama, Luis; Macías, Alejandro; Pérez-Lourido, Paulo; Valencia, Laura


    The interaction between Co(II) and Cu(II) ions with a Py(2)N(4)S(2)-coordinating octadentate macrocyclic ligand (L) to afford dinuclear compounds has been investigated. The complexes were characterized by microanalysis, conductivity measurements, IR spectroscopy and liquid secondary ion mass spectrometry. The crystal structure of the compounds [H(4)L](NO(3))(4), [Cu(2)LCl(2)](NO(3))(2) (5), [Cu(2)L(NO(3))(2)](NO(3))(2) (6), and [Cu(2)L(μ-OH)](ClO(4))(3)·H(2)O (7) was also determined by single-crystal X-ray diffraction. The [H(4)L](4+) cation crystal structure presents two different conformations, planar and step, with intermolecular face-to-face π,π-stacking interactions between the pyridinic rings. Complexes 5 and 6 show the metal ions in a slightly distorted square-pyramidal coordination geometry. In the case of complex 7, the crystal structure presents the two metal ions joined by a μ-hydroxo bridge and the Cu(II) centers in a slightly distorted square plane or a tetragonally distorted octahedral geometry, taking into account weak interactions in axial positions. Electron paramagnetic resonance spectroscopy is in accordance with the dinuclear nature of the complexes, with an octahedral environment for the cobalt(II) compounds and square-pyramidal or tetragonally elongated octahedral geometries for the copper(II) compounds. The magnetic behavior is consistent with the existence of antiferromagnetic interactions between the ions for cobalt(II) and copper(II) complexes, while for the Co(II) ones, this behavior could also be explained by spin-orbit coupling.

  6. Comprehensive Vibrational Spectroscopic Investigation of trans,trans,trans-[Pt(N3)2(OH)2(py)2], a Pt(IV) Diazido Anticancer Prodrug Candidate.

    Vernooij, Robbin R; Joshi, Tanmaya; Shaili, Evyenia; Kubeil, Manja; Appadoo, Dominique R T; Izgorodina, Ekaterina I; Graham, Bim; Sadler, Peter J; Wood, Bayden R; Spiccia, Leone


    We report a detailed study of a promising photoactivatable metal-based anticancer prodrug candidate, trans,trans,trans-[Pt(N3)2(OH)2(py)2] (C1; py = pyridine), using vibrational spectroscopic techniques. Attenuated total reflection Fourier transform infrared (ATR-FTIR), Raman, and synchrotron radiation far-IR (SR-FIR) spectroscopies were applied to obtain highly resolved ligand and Pt-ligand vibrations for C1 and its precursors (trans-[Pt(N3)2(py)2] (C2) and trans-[PtCl2(py)2] (C3)). Distinct IR- and Raman-active vibrational modes were assigned with the aid of density functional theory calculations, and trends in the frequency shifts as a function of changing Pt coordination environment were determined and detailed for the first time. The data provide the ligand and Pt-ligand (azide, hydroxide, pyridine) vibrational signatures for C1 in the mid- and far-IR region, which will provide a basis for the better understanding of the interaction of C1 with biomolecules.

  7. X-ray transient absorption structural characterization of the 3MLCT triplet excited state of cis-[Ru(bpy)2(py)2]2+.

    Borfecchia, Elisa; Garino, Claudio; Salassa, Luca; Ruiu, Tiziana; Gianolio, Diego; Zhang, Xiaoyi; Attenkofer, Klaus; Chen, Lin X; Gobetto, Roberto; Sadler, Peter J; Lamberti, Carlo


    The excited state dynamics and structure of the photochemically active complex cis-[Ru(bpy)2(py)2](2+) have been investigated using optical transient absorption (OTA) and X-ray transient absorption (XTA) spectroscopy, and density functional theory (DFT). Upon light-excitation in aqueous solution cis-[Ru(bpy)2(py)2](2+) undergoes ultrafast dissociation of one pyridine ligand to form cis-[Ru(bpy)2(py)(H2O)](2+). OTA measurements highlighted the presence of two major time components of 1700 ps and 130 ps through which the system decays to the ground-state and evolves towards the photoproduct. XTA data were acquired after 150 ps, 500 ps, and 3000 ps from laser excitation (λexc = 351 nm) and provided the transient structure of the (3)MLCT state corresponding to the longer time component in the OTA experiment. In excellent agreement with DFT, XTA shows that the (3)MLCT geometry is characterized by an elongation of the dissociating Ru-N(py) bond and a shortening of the trans Ru-N(bpy) bond with respect to the ground state. Conversely, calculations show that the (3)MC state has a highly distorted structure with Ru-N(py) bonds between 2.77-3.05 Å.

  8. Synthesis and Crystal Structure of a 1-D Coordination Polymer {[Cu(NIT4py)2(ip)]·6H2O}n

    WANG Shu-Ping; GAO Dong-Zhao; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping; LI Li-Cun


    A new complex {[Cu(NIT4py)2(ip)]·6H2O}n (NIT4py=2-(4'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and ip = isophthalate dianion) has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in orthorhombic, space group Cmcm with a = 25.161(3), b =10.045(1), c = 15.450(2)(A), C32H48N6O14Cu, Mr = 804.30, V = 3904.8(8)(A)3, Z = 4, Dc = 1.368 g/cm3,μ(MoKα) = 0.630 mm-1, F(000) = 1692, the final R = 0.0326 and wR = 0.0787 for 1843 independent reflections with Rint = 0.0372. Each Cu(II) ion is four-coordinated by two carboxylate oxygen atoms and two pyridyl-N atoms from NIT4py radicals to furnish a rhombus geometry. The central Cu(II) ion is located at an inversion center and a crystallographic two-fold axis. Each isophthalate dianion binds two Cu(II) ions in bis-monodentate mode, leading to a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

  9. Synthesis, Crystal Structure and Optical Properties of a New Nd(Ⅲ) Nitronyl Nitroxide Complex [Nd(NIT2Py)2(NO3)3

    LI Dong-Jiao; GAO Dong-Zhao; LI Li-Cun; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping


    A new Nd(Ⅲ) nitronyl nitroxide complex [Nd(NIT2Py)2(NO3)3] (NIT2Py = 2-(2'-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been synthesized and structurally characterized by X-ray diffraction.It crystallizes in monoclinic, space group P21/n with a = 12.396(4), b =11.134(4), c = 23.360(7)(。A), β = 98.178(6)°, V= 3191.2(18)(。A)3, C24H32NgNdO13, Mr = 798.83, Dc =1.663 g/cm3, μ(MoKα) = 1.704 mm-1, F(000) = 1612, Z = 4, the final R = 0.0425 and wR = 0.0957for 6532 independentreflections with Rint = 0.0642 and 4552 observed reflections (I > 2σ(I)).The complex exists as discrete mononuclear molecules and the neodymium(Ⅲ) ion is ten-coordinated with three bidentate nitrate anions and two radical ligands (NIT2Py) via bidentate chelating mode.The optical properties of the complex are discussed.

  10. 关于Diophantine方程x3-53=3py2%The Diophantine equation x3 -53=3 p y2

    杨海; 武静; 任荣珍


    Let p be a fixed prime .By using some elementary number theory methods ,it is proved that the equation x3 -53 =3py2 has positive integer solution (x ,y) with gcd(x ,y)=1 if and only if p= Q(27a4 +45a2 +25) ,where a is a positive integer and Q(27a4 +45a2 +25) is the square free factor of 27a4 +45a2+25 .Thus ,if p≢7 or 13(mod30) ,the equation has no positive integer solutions (x ,y) with gcd(x ,y)=1.%设 p是给定的素数,运用初等数论方法证明了方程x3-53=3 py2有适合gcd(x ,y)=1的正整数解(x ,y)的充要条件是 p = Q(27 a4+45 a2+25),其中a是正整数,Q(27 a4+45 a2+25)是27 a4+45 a2+25的无平方因子部分。由此可知,当 p ≢7或13(m o d30)时,该方程没有适合gcd(x ,y)=1的正整数解(x ,y)。

  11. Crystal structure analysis and chiral recognition study of Delta-[Ru(bpy)2(py)2][(+)-O,O'-dibenzoylD-tartrate].12H2O and Lambda-[Ru(bpy)2(py)2][(-)-O,O'-dibenzoyl-L-tartrate].12H2O.

    Kolp, B; Viebrock, H; von Zelewsky, A; Abeln, D


    The molecular structure and crystal-packing mode of the enantiopure chiral building blocks Delta-[Ru(bpy)(2)(py)(2)][(+)-O,O'-dibenzoyl-D-tartrate].12H(2)O (I) and Lambda-[Ru(bpy)(2)(py)(2)][(-)-O,O'-dibenzoyl-L-tartrate].12H(2)O (II) have been determined by single-crystal X-ray diffraction data. This study proposes a model of how the L- and D-dibenzoyltartrate anions recognize the chirality of the hydrophobic [Ru(bpy)(2)(py)(2)](2+) complex. The monoclinic unit cell contains four complex cations, four tartrate anions, and 48 water molecules. Since there are no possibilities to form hydrogen bonds between the cations and anions, chiral recognition is due to crystal packing. Two benzoyl rings of two different tartrate anions are gripping the two bpy-planes of the Ru-complex. Further a third benzoyl ring from a tartrate anion is packed between the two pyridine rings, favoring one enantiomeric form to crystallize from aqueous solution. Crystal structure data for I at 153 K: a = 15.342(3) A, b = 19.200(4) A, c = 18.872(4) A, beta = 104.841(3) degrees, monoclinic space group C(2), R(1)= 0.0239 (I > 2sigma(I)), R(2) = 0.0606, Flack parameter = 0.0115 (with esd 0.0166). For II at 293 K: a = 15.376(4) A, b = 19.388(11) A, c = 19.085(7) A, beta = 105.11(2) degrees, monoclinic space group C121, R(1)= 0.0686 (I > 2sigma(I)), R(2) = 0.1819, Flack parameter = -0.0100 (with esd 0.0521).

  12. Cap for copper(I) ions! Metallosupramolecular solid and solution state structures on the basis of the dynamic tetrahedral [Cu(phenAr2)(py)2]+ motif.

    Schmittel, Michael; He, Bice; Fan, Jian; Bats, Jan W; Engeser, Marianne; Schlosser, Marc; Deiseroth, Hans-Jörg


    The tetrahedral [Cu(phenAr(2))(py)(2)](+) coordination motif (phen = 1,10-phenanthroline; py = pyridine) conceived on the basis of the HETPYP concept (heteroleptic pyridyl and phenanthroline metal complexes) is a versatile dynamic unit for constructing various heteroleptic metallosupramolecular pseudo-1D, 2D, and 3D structures, both in solution and the solid state. The 2,9-diaryl substituted phenanthroline (phenAr(2)) serves as a capping ligand for copper(I) ions, as its bulky nature prevents formation of the homoleptic complex [Cu(phenAr(2))(2)](+). Combination of the dynamic and concave metal ligand building block [Cu(phenAr(2))](+) with various pyridine (py) ligands, such as bi-, tri-, and tetra-pyridines, opened the way to infinite 1D helicates, 2D networks, and discrete 3D hexanuclear cages, whereas spatial integration of both phenAr(2) and py units into a single ligand resulted in the formation of a Borromean-ring-type hexanuclear cage.

  13. Synthesis and Structure of a Novel Compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O

    TANG Ding-Xing; ZHAO Yun


    A novel compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O was synthesized by the reaction of CuSO4(5H2O with H4EDTA in pyridine/water (V/V = 1/4) solvent, and characterized by elemental analysis, IR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 1.26974(6), b = 0.67949(3), c = 1.48548(3) nm, β = 91.454(2)o, V = 1.28122(9) nm3, Z = 2, Dc = 1.673 g/cm3, Mr = 645.56, F(000) = 664, μ(MoKα) = 1.729 mm-1, the final R = 0.0353 and wR = 0.0832 for 1920 observed reflections (I > 2((I)). The compound is a centrosymmetric binuclear molecule with bridged EDTA group. Each Cu(II) atom is linked to two oxygen atoms and one nitrogen atom of EDTA, one oxygen atom of water and one nitrogen atom of pyridine to form a distorted square pyramidal environment. There exist face-to-face π-π stacking interactions between pyridine rings from neighboring molecule with the interplanar distance of 0.3670 nm and hydrogen bonding between EDTA and water molecules.

  14. Structure of the complex of [Ru(tpm)(dppz)py](2+) with a B-DNA oligonucleotide - a single-substituent binding switch for a metallo-intercalator.

    Waywell, Philip; Gonzalez, Veronica; Gill, Martin R; Adams, Harry; Meijer, Anthony J H M; Williamson, Mike P; Thomas, James A


    We report the synthesis of three new complexes related to the achiral [Ru(tpm)(dppz)py](2+) cation (tpm=tripyridazole methane, dppz=dipyrido[3,2-a:2',3'-c]phenazine, py=pyridine) that contain an additional single functional group on the monodentate ancillary pyridyl ligand. Computational calculations indicate that the coordinated pyridyl rings are in a fixed orientation parallel to the dppz axis, and that the electrostatic properties of the complexes are very similar. DNA binding studies on the new complexes reveal that the nature and positioning of the functional group has a profound effect on the binding mode and affinity of these complexes. To explore the molecular and structural basis of these effects, circular dichroism and NMR studies on [Ru(tpm)(dppz)py]Cl(2) with the octanucleotides d(AGAGCTCT)(2) and d(CGAGCTCG)(2), were carried out. These studies demonstrate that the dppz ligand intercalates into the G(2)-A(3) step, with {Ru(tpm)py} in the minor groove. They also reveal that the complex intercalates into the binding site in two possible orientations with the pyridyl ligand of the major conformer making close contact with terminal base pairs. We conclude that substitution at the 2- or 3-position of the pyridine ring has little effect on binding, but that substitution at the 4-position drastically disrupts intercalative binding, particularly with a 4-amino substituent, because of steric and electronic interactions with the DNA. These results indicate that complexes derived from these systems have the potential to function as sequence-specific light-switch systems.

  15. Anisotropic magnetic interactions and spin dynamics in the spin-chain compound Cu (py) 2Br2 : An experimental and theoretical study

    Zeisner, J.; Brockmann, M.; Zimmermann, S.; Weiße, A.; Thede, M.; Ressouche, E.; Povarov, K. Yu.; Zheludev, A.; Klümper, A.; Büchner, B.; Kataev, V.; Göhmann, F.


    We compare theoretical results for electron spin resonance (ESR) properties of the Heisenberg-Ising Hamiltonian with ESR experiments on the quasi-one-dimensional magnet Cu (py) 2Br2 (CPB). Our measurements were performed over a wide frequency and temperature range giving insight into the spin dynamics, spin structure, and magnetic anisotropy of this compound. By analyzing the angular dependence of ESR parameters (resonance shift and linewidth) at room temperature, we show that the two weakly coupled inequivalent spin-chain types inside the compound are well described by Heisenberg-Ising chains with their magnetic anisotropy axes perpendicular to the chain direction and almost perpendicular to each other. We further determine the full g tensor from these data. In addition, the angular dependence of the linewidth at high temperatures gives us access to the exponent of the algebraic decay of a dynamical correlation function of the isotropic Heisenberg chain. From the temperature dependence of static susceptibilities, we extract the strength of the exchange coupling (J /kB=52.0 K ) and the anisotropy parameter (δ ≈-0.02 ) of the model Hamiltonian. An independent compatible value of δ is obtained by comparing the exact prediction for the resonance shift at low temperatures with high-frequency ESR data recorded at 4 K . The spin structure in the ordered state implied by the two (almost) perpendicular anisotropy axes is in accordance with the propagation vector determined from neutron scattering experiments. In addition to undoped samples, we study the impact of partial substitution of Br by Cl ions on spin dynamics. From the dependence of the ESR linewidth on the doping level, we infer an effective decoupling of the anisotropic component J δ from the isotropic exchange J in these systems.

  16. Syntheses, Structure, Magnetic Properties and 57Fe Mossbauer Spectroscopies of Two Iron(Ⅱ) Complexes: Room-temperature Spin Crossover Behavior Observed in [Fe(dpq)(MePy)2(NCS)2

    TAO, Jianqing; GU, Yunlan; ZHOU, Xinhui; GU, Zhiguo; ZUO, Jinglin; YOU, Xiaozeng


    Two new complexes [Fe(dpq)(MePy)2(NCS)2] (1) and [Fe(Medpq)(MePy)2(NCS)2] (2) (dpq=2-dipyrido[3,2-f: 2',3'-h]quinoxaline, Medpq=2-methyidipyrido[3,2-f.2',3'-h]quinoxaline, MePy=4-methylpyridine) have been syn- thesized. The crystal structure of 2 was characterized by X-ray diffraction at room temperature. It crystallizes in or- thorhombic space group I212121, with a =15.057(3)A, b =14.569(3)A, c=13.180(3) A,α=90.00°,β= 90.00°,γ= 90.00°, and V=2891.2(11)A3. The distorted [FEN6] octahedron in 2 is formed by six nitrogen atoms from Medpq, two trans-MePy molecules and two cis-NCS- anions. Variable-temperature magnetic susceptibilities and Moss- bauer spectroscopies of 1 and 2 reveal the occurrence of a gradual spin transition. The transition for I spans the 200 -450 K temperature range with a T1/2 of 340 K, while for 2, the transition in low temperature is incomplete.

  17. Synthesis and Crystal Structure of Dinuclear Copper Complex [Cu(CH2O(C6H4)N=C(C6H4)O)(Py)]2

    牛德仲; 沐来龙; 路再生; 王玉成; 陈久桐


    The complex [Cu2L2(Py)2] (H2L=2-aminobenzoic alcohol condensation salicylaldehyde) was obtained. A single-crystal X-ray study shows that the complex is a binuclear compound (Cu2C38H32N4O4). The coordination geometry about each copper atom is best described as a distorted square pyramid. The compound [Cu2L2(Py)2] belongs to monoclinic system with space group P21, lattice constants: a = 10.3881(1), b = 17.9724(1), c = 17.5800(2) A, β =90.4880(1)°, V= 3282.05(5) A3, Z= 4, Mr =735.75, Dc=1.489 g/cm3, μ= 1.344mm-1, F(000) = 1512, R=0.0519, wR=0.1092 for 6725 reflections with I >2σ(I). The distances between Cu(II) and O atoms are range from 1.898(6) to1.976(5)A, between Cu(II) and N atoms are range from 1.990(6) to 2.369(7)A. The Cu(1)-Cu(2) bond length is 3.024(4) A.

  18. Thermal- and light-induced spin crossover in novel 2D Fe(II) metalorganic frameworks {Fe(4-PhPy)(2)[M(II)(CN)(x)](y)}.sH(2)O: spectroscopic, structural, and magnetic studies.

    Seredyuk, M; Gaspar, A B; Ksenofontov, V; Verdaguer, M; Villain, F; Gütlich, P


    Five novel two-dimensional coordination polymers {Fe(4PhPy)(2)[M(II)(CN)(4)]}.sH(2)O (4PhyPy = 4-phenylpyridine; 1: M(II) = Pd, s = 0; 2: M(II) = Ni, s = 0; 3: M(II) = Pt, s = 1) and {Fe(4PhPy)(2)[M(I)(CN)(2)](2)}.sH(2)O (4: M(I) = Ag, s = 1; 5: M(I) = Au, s = 0.5) exhibiting spin-crossover properties have been synthesized. They were characterized at various temperatures using X-ray absorption spectroscopy (XAS), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and magnetic susceptibility measurements. The occurrence of a cooperative thermal spin transition detected by the magnetic method is located at critical temperatures T(c)( downward arrow)/T(c)( upward arrow) = 163 K/203 K (1), 135 K/158 K (2), and 172 K/221 K (3), and a less cooperative one is located at T(c) = 188 K (4) and 225 K (5). Compounds 1-5 show an abrupt color change from yellow (high-spin (HS) state) to red (low-spin (LS) state) upon spin-state conversion. The dehydration of the compounds changes the type of the spin transition, making it more abrupt and shifting the critical temperature to higher temperatures. For 1 and 2, XAS provides local structural information on the contraction of the FeN(6) coordination sphere upon the HS-to-LS transition, in line with the magnetic results. Variable-temperature characterization of 1 by X-ray diffraction evidences the very abrupt phase transition with a large hysteresis. A light-induced spin conversion (LIESST effect) is detected by magnetic measurements in 1-5 below 70 K.

  19. Speciation study of the anti-inflammatory drug tenoxicam (Htenox) with Cu(II): X-ray crystal structure of [Cu(tenox)(2)(py)(2)].EtOH.

    Moya-Hernández, M R; Mederos, A; Domínguez, S; Orlandini, A; Ghilardi, C A; Cecconi, F; González-Vergara, E; Rojas-Hernández, A


    A speciation study was carried out in aqueous solution of the anti-inflammatory drug tenoxicam (Htenox), under quasi-physiological conditions (temperature of 37 degrees C and ionic strength 0.15 M NaCl) in order to determine the acidity constants from spectrophotometric studies, the pK(a) values found being pK(1)=1.143+/-0.008 and pK(2)=4.970+/-0.004. Subsequently, the spectrophotometrical speciation of the different complexes of Cu(II) with the drug was performed under the same conditions of temperature and ionic strength, observing the formation of Cu(Htenox)(2)(2+) with log beta(212)=20.05+/-0.01, Cu(tenox)(2) with log beta(012)=13.6+/-0.1, Cu(Htenox)(2+) with log beta(111)=10.52+/-0.08, as well as Cu(tenox)(+) with log beta(011)=7.0+/-0.2, all of them in solution, and solid species Cu(tenox)(2)(s) with an estimated value of log beta(012)(s) approximately 18.7. The crystalline structure of the complex [Cu(tenox)(2)(py)(2)]. EtOH, was also determined, and it was observed that tenoxicam employs the oxygen of the amide group and the pyridyl nitrogen to bond to the cation.

  20. Synthesis and Crystal Structure of Adamantanecarboxylic Acid Complex with Cu(Ⅱ)%金刚烷甲酸铜(Ⅱ)配合物Cu(ada)2(py)2(H2O)的合成和晶体结构

    冯云龙; 胡晓春; 孔黎春


    @@ 铜与有机酸形成的配合物对生命体系有着特殊的生物活性和催化作用[1]. 模拟合成生命体系中铜(Ⅱ)与有机酸形成的配合物并对其结构和性能进行研究,对揭示金属酶的结构和认识生命现象具有重要意义[2]. 铜与羧酸作为配位基团的有机酸根形成的配合物已有许多报道[3~5],而以金刚烷基甲酸(adamantanecarboxylic acid,Hada)为配体的金属配合物未见文献报道. 本文以Hada为配体合成了单核铜(Ⅱ)配合物Cu(ada)2(py)2(H2O),对其进行了元素分析和红外光谱表征,并测定了晶体结构.

  1. Synthesis and Crystal Structure of a Tetranuclear Carboxylate-bridged Lanthanum(III)-Zinc(II) Complex [La2Zn2(m-CNC6H4COO)10(Py)2(C2H5OH)2


    The title complex was prepared from self-assembly reaction of La(NO3)3×6H2O, Zn(NO3)2×6H2O, m-cyanobenzoic acid (m-CNC6H4COOH) and pyridine (Py) in refluxing ethanol and its structure was determined by single-crystal X-ray diffraction. Crystallographic data: C94H62N12La2O22Zn2, Mr = 2120.12, triclinic space group P _ 1, a = 13.2219(5), b = 13.2713(5), c = 14.1987(6) ?, a = 69.156(1), b = 84.034(1), g = 89.400(1) °, V = 2314.9(2) ?3, Z = 1, Dc = 1.521 g/cm3, F(000) = 1060, m (MoKa) = 14.94 cm-1, the final R = 0.043 and wR = 0.117 for 6381 unique reflections with I > 2s(I). Crystal structure determination shows that the neighboring lanthanum(III) and zinc(II) ions are bridged by three bidentate m-cyanobenzonate ligands in the syn-syn fashion to form a pair of dinuclear [LaZn(m-CNC6H4COO)3(Py)(C2H5OH)] subunits, being linked together by two bidentate and two tridentate m-cyanobenzonate groups in the syn-syn and syn-anti modes, respectively, to construct a tetranuclear La-Zn complex [La2Zn2(m-CNC6H4COO)10(Py)2(C2H5OH)2].

  2. On the Integer Solution of the Indeterminate Equation x3+8=py2%关于不定方程x3+8=py2的整数解的研究



    Let p=3(8k+5)(8k+6)+1 )(k∈N be an odd prime. By using the elementary method, the sufficient condition of positive integer solution is proved on the condition that the indeterminate equation 2x 3+8= py )( x, y∈N has no integer solutions with gcd(x, y)=1.%设 p=3(8k+5)(8k+6)+1)(k∈N 为奇素数,利用初等方法证明了不定方程x3+82= py 无gcd(x, y)=1的正整数解的一个充分条件。

  3. Antibacterial Activity and Cytotoxicity of Silver(I) Complexes of Pyridine and (Benz)Imidazole Derivatives. X-ray Crystal Structure of [Ag(2,6-di(CH2OH)py)2]NO3.

    Kalinowska-Lis, Urszula; Felczak, Aleksandra; Chęcińska, Lilianna; Szabłowska-Gadomska, Ilona; Patyna, Emila; Małecki, Maciej; Lisowska, Katarzyna; Ochocki, Justyn


    Selected aspects of the biological activity of a series of six nitrate silver(I) complexes with pyridine and (benz)imidazole derivatives were investigated. The present study evaluated the antibacterial activities of the complexes against three Gram-negative strains: Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 25922 and Proteus hauseri ATCC 13315. The results were compared with those of silver nitrate, a silver sulfadiazine drug and appropriate ligands. The most significant antibacterial properties were exerted by silver(I) complexes containing benzimidazole derivatives. The cytotoxic activity of the complexes was examined against B16 (murine melanoma) and 10T1/2 (murine fibroblasts) cells. All of the tested silver(I) compounds were not toxic to fibroblast cells in concentration inhibited cancer cell (B16) viability by 50%, which ranged between 2.44-28.65 µM. The molecular and crystal structure of silver(I) complex of 2,6-di(hydroxymethyl)pyridine was determined by single-crystal X-ray diffraction analysis. The most important features of the crystal packing and intermolecular non-covalent interactions in the Ag(I) complex were quantified via Hirshfeld surface analysis.

  4. Triggering the Generation of an Iron(IV)-Oxo Compound and Its Reactivity toward Sulfides by Ru-II Photocatalysis

    Company, Anna; Sabenya, Gerard; Gonzalez-Bejar, Maria; Gomez, Laura; Clemancey, Martin; Blondin, Genevieve; Jasniewski, Andrew J.; Puri, Mayank; Browne, Wesley R.; Latour, Jean-Marc; Que, Lawrence; Costas, Miguel; Perez-Prieto, Julia; Lloret-Fillol, Julio


    The preparation of [Fe-IV(O)(MePy(2)tacn)](2+) (2, MePy(2)tacn = N-methyl-N,N-b is (2-picolyl)- 1,4,7-triazacy-clononane) by reaction of [Fe-II(MePy(2)tacn)(solvent)](2+) (1) and PhIO in CH3CN and its full characterization are described. This compound can also be prepared photochemically from its ir

  5. Triggering the Generation of an Iron(IV)-Oxo Compound and Its Reactivity toward Sulfides by Ru-II Photocatalysis

    Company, Anna; Sabenya, Gerard; Gonzalez-Bejar, Maria; Gomez, Laura; Clemancey, Martin; Blondin, Genevieve; Jasniewski, Andrew J.; Puri, Mayank; Browne, Wesley R.; Latour, Jean-Marc; Que, Lawrence; Costas, Miguel; Perez-Prieto, Julia; Lloret-Fillol, Julio


    The preparation of [Fe-IV(O)(MePy(2)tacn)](2+) (2, MePy(2)tacn = N-methyl-N,N-b is (2-picolyl)- 1,4,7-triazacy-clononane) by reaction of [Fe-II(MePy(2)tacn)(solvent)](2+) (1) and PhIO in CH3CN and its full characterization are described. This compound can also be prepared photochemically from its

  6. A Thermodynamic Study on the Binding of Human Serum Albumin with New synthesized Anticancer Pd(II Complex



    Full Text Available The thermodynamics interaction between new synthesized anti-cancer drugcomplex, Pd2Py2, and HSA wasinvestigated at pH 7 by isothermal titration calorimetry. The extended solvation model was used to reproduce the enthalpies of HSA interaction withPd2Py2. The solvation parameters obtained from the new model was attributed to the structural change and anti-oxidant property of HSA. The binding parameters for the interaction of Pd2Py2 and HSA indicated that the considerable conformational changes in HSA were not observed after binding toPd2Py2.

  7. NCBI nr-aa BLAST: CBRC-PHAM-01-0651 [SEVENS

    Full Text Available CBRC-PHAM-01-0651 ref|YP_001418797.1| DNA protecting protein DprA [Xanthobacter aut...otrophicus Py2] gb|ABS69140.1| DNA protecting protein DprA [Xanthobacter autotrophicus Py2] YP_001418797.1 3.1 31% ...

  8. Experiment list: SRX483142 [Chip-atlas[Archive

    Full Text Available SM1342160: Input Tead2 biological rep1; Mus musculus; ChIP-Seq source_name=Py2T breast cancer cells || cell ...SRX483142 mm9 Input control Input control Breast Py2T NA 241448456,93.2,66.7,1863 G

  9. Preparation of Polysaccharide from Porphyra yezoensis Ueda and Its Effects on Growth of Lymphocytes%一种紫菜多糖的制备及 对淋巴细胞生长的影响

    张伟云; 刘宇峰; 侯亚义; 陈颢; 谭仁祥


    用DEAE-纤维素和Sephadex G-200 柱层析法分离纯化条斑紫菜的热水提取物,从中得到多糖PY2,并测出其分子量为2.0×104。用紫外和红外光谱对PY2的性质进行了鉴定。进一步测定了PY2对体外培养的小鼠骨髓细胞及淋巴细胞生长的影响。结果表明,PY2是一种少见的紫菜多糖,它不含有大多数紫菜多糖具有的3,6-内醚-半乳糖和硫酸基, 它对小鼠脾脏淋巴细胞、胸腺淋巴细胞以及混合淋巴细胞的增殖有一定的抑制作用,而对骨髓细胞的增殖没有明显的影响。%The purified polysaccharide PY2 was obtained by DEAE-cellulose and Sephadex G-200 column chromatography from Porphyra yezoensis. The average molecular weight was determined to be 2.0×104 by using column chromatography. PY2 was also identified by UV and IR spectra. The results showed that PY2 is a kind of infrequent polysaccharide from Porphyra,which could inhibit the proliferation of murine spleen cells, thymus cells and mixed lymphocyte reaction. There were no distinct effects of PY2 on bone marrow cells.

  10. CuI Thiolate Reactivity with Dioxygen: The Formation of CuII Sulfinate and CuII Sulfonate Species via a CuII Thiolate Intermediate

    Ording-Wenker, E.C.M.; Siegler, M.A.M.; Lutz, M.; Bouwman, E.


    CuI(Py2NS) (1) is formed by addition of CuI to a solution of the pyridyl-thiol ligand N-(2-mercaptopropyl)- N,N-bis(2-pyridylmethyl)amine (Py2NSH). Oxidation of complex 1 by air leads to the formation of CuII sulfinate and CuII sulfonate complexes, providing a model for the oxidative degeneration of

  11. ''Isolation'' of the proximity-induced triplet pairing channel in the superconductor/ferromagnet spin valve

    Leksin, Pavel [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Zavoisky Physical-Technical Institute, Russian Academy of Sciences, Kazan (Russian Federation); Garifyanov, Nadir; Kamashev, Andrey; Validov, Aidar; Garifullin, Ilgiz [Zavoisky Physical-Technical Institute, Russian Academy of Sciences, Kazan (Russian Federation); Fominov, Yakov [L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny (Russian Federation); Schumann, Joachim; Kataev, Vladislav; Thomas, Juergen [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Buechner, Bernd [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Institute for Solid State Physics, Technical University Dresden (Germany)


    We have studied the proximity induced superconducting triplet pairing in CoO{sub x}/Py1/Cu/Py2/Cu/Pb spin-valve structure. By optimizing the parameters of structures we found a full switching between the normal and superconducting states. To observe an ''isolated'' triplet spin-valve effect we exploited the oscillatory feature of the magnitude of the ordinary spin-valve effect ΔT{sub c} in the dependence of the Py2-layer thickness d{sub Py2}. We determined the value of d{sub Py2} at which ΔT{sub c} caused by the ordinary spin-valve effect (the difference in T{sub c} between antiparallel and parallel mutual orientation of magnetizations of the Py1 and Py2 layers) is suppressed. For such a sample a ''pure'' triplet spin-valve effect which causes the minimum in T{sub c} at the orthogonal configuration of magnetizations has been observed.

  12. Copper, indium, tin, and lead complexes with fluorinated selenolate ligands: precursors to MSex.

    Holligan, Kareem; Rogler, Patrick; Rehe, David; Pamula, Michael; Kornienko, Anna Y; Emge, Thomas J; Krogh-Jespersen, Karsten; Brennan, John G


    Reductive cleavage of C6F5SeSeC6F5 with elemental M (M = Cu, In, Sn, Pb) in pyridine results in the formation of (py)4Cu2(SeC6F5)2, (py)2In(SeC6F5)3, (py)2Sn(SeC6F5)2, and (py)2Pb(SeC6F5)2. Each group adopts a unique structure: the Cu(I) compound crystallizes as a dimer with a pair of bridging selenolates, two pyridine ligands coordinating to each Cu(I) ion, and a short Cu(I)-Cu(I) distance (2.595 Å). The indium compound crystallizes as monometallic five-coordinate (py)2In(SeC6F5)3 in a geometry that approximates a trigonal bipyramidal structure with two axial pyridine ligands and three selenolates. The tin and lead derivatives (py)2M(SeC6F5)2 are also monomeric, but they adopt nearly octahedral geometries with trans pyridine ligands, a pair of cis-selenolates, and two "empty" cis-positions on the octahedron that are oriented toward extremely remote selenolates (M-Se = 3.79 Å (Sn), 3.70 Å (Pb)) from adjacent molecules. Two of the four compounds (Cu, In) exhibit intermolecular π-π stacking arrangements in the solid state, whereas the stacking of molecules for the other two compounds (Sn, Pb) appears to be based upon molecular shape and crystal packing forces. All compounds are volatile and decompose at elevated temperatures to give MSex and Se(C6F5)2.The electronic structures of the dimeric Cu compound and monomeric (py)2M(SeC6F5)2 (M = Sn, Pb) were examined with density functional theory calculations.

  13. A tetrakis(amido)phosphonium cation containing 2-pyridyl (2Py) substituents,[P(NH2Py)4]+ and its reactivity studies with Ag(I) salts

    Arvind K Gupta; Anant Kumar Srivastava; Ramamoorthy Boomishankar


    Poly-imido analogues of various phosphorus oxo anions have gained recent attention in inorganic chemistry. Current methods to obtain these anions require strong organometallic deprotonating agents in reaction with phosphonium salt like [(NHPh)4P]Cl or phosphoramides such as [(RNH)3P=E] (E = NSiMe3, O, S or Se) in non-polar solvents. Recently, employing salts of soft and reactive transition metal ions, we have developed methods to obtain these anions in polar and protic solvents. Herein, we have described a facile anion exchange route that stabilizes the highly labile tetrakis(2-pyridylamino)phosphonium cation as its nitrate salt, [P(NH2Py)4]NO3. This molecule exhibits a double chain structure mediated by H-bonding interactions of the pyridylamino segments (N-H...N). The phosphonium salt upon reaction with excess silver triflate results in a pentanuclear Ag(I) complex, {Ag5[P(N2Py)2(NH2Py)2]}·(F3CSO3)3, stabilized by two imido-phosphinate [P(N2Py)2(NH2Py)2]− ligands. Formation of a similar penta-nuclear cluster has been observed before when AgClO4 was used as a base. Our previous results with the related phosphate precursor, [PO(NH2Py)3], in reaction with various Ag(I) salts have shown to yield complexes of the corresponding neutral, mono- and dianionic ligands. However, the stability of the Ag5-cluster within the mono-anionic casing of the [P(N2Py)2(NH2Py)2]− ligand have seemingly overwhelmed the subtle reactivity changes offered by various Ag(I) salts.

  14. Fully Oxidized and Mixed-Valent Polyoxomolybdates Structured by Bisphosphonates with Pendant Pyridine Groups: Synthesis, Structure and Photochromic Properties

    Olivier Oms


    Full Text Available Hybrid organic-inorganic polyoxometalates (POMs were synthesized in water by the reaction of a MoVI precursor with bisphosphonate ligands functionalized by pyridine groups. The fully oxidized POM [(MoVI3O82(O(O3PC(O(C3H6NH2CH2C5H4NHPO32]4− has been isolated as water insoluble pure Na salt (NaMo6(Ale-4Py2 or mixed Na/K salt (NaKMo6(Ale-4Py2 and their structure solved using single-crystal X-ray diffraction. The mixed-valent complex [(MoV2O4(MoVI2O62{O3PC(O(C3H6N(CH2C5H4N2(MoVIO3PO3}2]8− was obtained as an ammonium salt (NH4Mo6(AlePy2Mo2, in the presence of a reducing agent (hydrazine. 31P NMR spectroscopic studies in aqueous media have allowed determining the pH stability domain of NH4Mo6(AlePy2Mo2. NaMo6(Ale-4Py2 and NaKMo6(Ale-4Py2 exhibit remarkable solid-state photochromic properties in ambient conditions. Under UV excitation, they develop a very fast color-change from white to deep purple and proved to be the fastest photochromic organoammonium/POM systems. The coloration kinetics has been fully quantified for both salts and is discussed in light of the hydrogen-bonding networks.

  15. O comportamento Fotoquímico dos Complexos Pentaaminas de Rutênio(II com Ligantes π Insaturados The photochemical behaviour of pentaamineruthenium(ii complexes with unsaturated π ligands

    Rose Maria Carlos


    Full Text Available A general overview on the photochemical behaviour of [Ru(NH35L]2+ complexes (where L is a p ligand is presented. The proposed mechanisms and techniques employed for the study of these reactions are discussed. Emphasis is made on the mechanisms that allow the identification of the reactive excited state of the [Ru(NH35py]2+ complex.

  16. Halide Influence on Molecular and Supramolecular Arrangements of Iron Complexes with a 3,5-Bis(2-Pyridyl)-1,2,4,6-Thiatriazine Ligand.

    Harriman, Katie L M; Kühne, Irina A; Leitch, Alicea A; Korobkov, Ilia; Clérac, Rodolphe; Murugesu, Muralee; Brusso, Jaclyn L


    A series of iron centered complexes, namely, [Fe(Py2TTA)Cl2] (1), [Fe(Py2TTA)Br2] (2), and [Fe(μ-F)(Py2TTAO)F]∞ (3), were isolated via complexation of 3,5-bis(2-pyridyl)-1,2,4,6-thiatriazine (Py2TTAH) with various ferric halides (e.g., FeF3, FeCl3, and FeBr3). Comparison of the optical and electrochemical spectroscopy, structural analysis, and magnetic studies reveal numerous similarities between the chlorido (1) and bromido (2) derivatives, which crystallize as discrete five-coordinate iron centered complexes with coordination geometries that are intermediate between trigonal bipyramidal and square base pyramid. Conversely, the fluorido derivative (3) results in a completely different structure due to oxidation of the ligand and the formation of a one-dimensional coordination polymer held together through a bridging fluoride ion. Consequently, the spectroscopic and magnetic behavior of 3 differs significantly compared with 1 and 2. Complexes 1 and 2 exhibit paramagnetic properties typical for a mononuclear S = 5/2 system with weak intermolecular antiferromagnetic interactions at low temperatures, whereas complex 3 demonstrates significant exchange couplings within the chain and weak antiferromagnetic interchain interactions, which stabilize a canted antiferromagnetic state below 4.2 K.

  17. Connecting mononuclear dysprosium single-molecule magnets to form dinuclear complexes via in situ ligand oxidation.

    Yutronkie, Nathan J; Kühne, Irina A; Korobkov, Ilia; Brusso, Jaclyn L; Murugesu, Muralee


    A Dy2 complex, exhibiting SMM behaviour, and its Y analogue were prepared via in situ oxidation of Py2TTA, a pincer type ligand, followed by dimerisation. This unique metal complexation and subsequent dimerization were followed by solution NMR studies.

  18. A hydrogen-bond facilitated cycle for oxygen reduction by an acid- and base-compatible iron platform.

    Soo, Han Sen; Komor, Alexis C; Iavarone, Anthony T; Chang, Christopher J


    We report a hydrogen-bond functionalized N4Py ligand platform (N,N-bis(2-R-6-pyridylmethyl)-N-bis(2-pyridyl)methylamine; R = neopentyl-NH, N4Py(2NpNH), 9; R = phenyl-NH, N4Py(2PhNH), 10) and the ability of its iron(II)-triflate [N4Py(2R)Fe(II)(OTf)][OTf] complexes (R = NpNH, 11; R = PhNH, 12) to activate and reduce dioxygen in a synthetic cycle by coupled proton and electron transfer. A pair of iron(III)-hydroxide [N4Py(2R)Fe(III)(OH)][OTf](2) complexes (R = NpNH, 13; R = PhNH, 14) are isolated and structurally and spectroscopically characterized after exposure of the iron(II)-triflate precursors to 1 atm of O(2) at ambient temperature. The stability of this system to acids and bases allows regeneration of the labile iron(II)-triflate starting materials by sequential electron and proton transfer with cobaltocene and triflic acid, respectively, or through direct proton-coupled reduction with ascorbic acid. In the stepwise process, reduction of the iron(III)-hydroxide complexes with cobaltocene gives structurally homologous iron(II)-hydroxide [N4Py(2R)Fe(II)(OH)][OTf] congeners (R = NpNH, 15; R = PhNH, 16) that can be prepared independently from 11 and 12 with 20% aq. NaOH. Additions of triflic acid to complexes 15 and 16 furnish the starting compounds 11 and 12, respectively, to complete the synthetic cycle. The combined data establish a synthetic cycle for O(2) reduction by an iron platform that manages proton and electron transfer through its first and second coordination spheres.

  19. Zinc, cadmium, and mercury complexes with fluorinated selenolate ligands.

    Emge, Thomas J; Romanelli, Michael D; Moore, Brian F; Brennan, John G


    Reductive cleavage of C(6)F(5)SeSeC(6)F(5) with elemental M (M = Zn, Cd, and Hg) in pyridine results in the formation of (py)(2)Zn(SeC(6)F(5))(2), (py)(2)Cd(SeC(6)F(5))(2), and Hg(SeC(6)F(5))(2). Structural characterization of the Zn and Cd compounds reveals tetrahedral coordination environments, while the Hg compound shows a complicated series of linear structures with two short, nearly linear Hg-Se bonds, up to two longer and perpendicular Hg...Se interactions, and no coordinated pyridine ligands. All three compounds exhibit well-defined intermolecular pi-pi-stacking interactions in the solid state. They are volatile and decompose at elevated temperatures to give MSe and either (SeC(6)F(5))(2) or Se(C(6)F(5))(2).

  20. Simulation of Tripod Gaits for a Hexapod Underwater Walking Machine


    fixed coordinates (P.. ,,y, P’ .). Then, we have 22 -bJ2 cosel = C’ = p. + pY2 _a° ,(4.14)2a-b, where b, = ((p aCOSo )2+(P., _aosin 0)2. ,J. 15...parametric representation of the arbitrary foot position (x, y) begins with x = acosO y = bsin . (6.1) The first derivative of equations 6.1 result in S

  1. Mechanistic implications of the active species involved in the oxidation of hydrocarbons by Iron complexes of pyrazine-2-carboxylic acid

    Tanase, Stefania; Marques-Gallego, Patricia; Browne, Wesley R.; Hage, Ronald; Bouwman, Elisabeth; Feringa, Ben L.; Reedijk, Jan


    The reactivity towards H2O2 of the complexes [Fe(pca)(2)(py)(2)]center dot py (1) and Na-2{[Fe(pca(3))](2)O}center dot 2H(2)O center dot CH3CN (2) (where pca(-) is pyrazine-2-carboxylate) and their catalytic activity in the oxidation of hydrocarbons is reported. Addition of H2O2 to 1 results in the

  2. Construction of nitronyl nitroxide-based 3d-4f clusters: structure and magnetism.

    Wang, Xiu-Feng; Hu, Peng; Li, Yun-Gai; Li, Li-Cun


    Three unprecedented nitronyl nitroxide radical-bridged 3d-4f clusters, [Ln2 Cu2 (hfac)10 (NIT-3py)2 (H2 O)2 ](Ln(III) =Y, Gd, Dy), have been obtained from the self-assembly of Ln(hfac)3 , Cu(hfac)2 , and the radical ligand. The Dy complex shows a slow relaxation of magnetization, representing the first nitronyl nitroxide radical-based 3d-4f cluster with single-molecule magnet behavior.

  3. Isolation of proximity-induced triplet pairing channel in a superconductor/ferromagnet spin valve

    Leksin, P. V.; Garif'yanov, N. N.; Kamashev, A. A.; Validov, A. A.; Fominov, Ya. V.; Schumann, J.; Kataev, V.; Thomas, J.; Büchner, B.; Garifullin, I. A.


    We have studied the proximity-induced superconducting triplet pairing in CoOx/Py1/Cu/Py2/Cu/Pb spin-valve structure (where Py = Ni0.81Fe0.19 ). By optimizing the parameters of this structure we found a triplet channel assisted full switching between the normal and superconducting states. To observe an "isolated" triplet spin-valve effect we exploited the oscillatory feature of the magnitude of the ordinary spin-valve effect Δ Tc in the dependence of the Py2-layer thickness dP y 2. We determined the value of dP y 2 at which Δ Tc caused by the ordinary spin-valve effect (the difference in the superconducting transition temperature Tc between the antiparallel and parallel mutual orientation of magnetizations of the Py1 and Py2 layers) is suppressed. For such a sample a "pure" triplet spin-valve effect which causes the minimum in Tc at the orthogonal configuration of magnetizations has been observed.

  4. Combined MCD/DFT/TDDFT Study of the Electronic Structure of Axially Pyridine Coordinated Metallocorroles.

    Rhoda, Hannah M; Crandall, Laura A; Geier, G Richard; Ziegler, Christopher J; Nemykin, Victor N


    A series of metallocorroles were investigated by UV-vis and magnetic circular dichroism spectroscopies. The diamagnetic distorted square-pyramidal main-group corrole Ga(tpfc)py (2), the diamagnetic distorted octahedral transition-metal adduct Co(tpfc)(py)2 (3), and paramagnetic distorted octahedral transition-metal complex Fe(tpfc)(py)2 (4) [H3tpfc = tris(perfluorophenyl)corrole] were studied to investigate similarities and differences in the electronic structure and spectroscopy of the closed- and open-shell metallocorroles. Similar to the free-base H3tpfc (1), inspection of the MCD Faraday B-terms for all of the macrocycles presented in this report revealed that a ΔHOMO absorption in the NIR region (1023 nm). DFT and TDDFT calculations were used to elaborate the electronic structures and provide band assignments in UV-vis and MCD spectra of the metallocorroles. DFT and TDDFT calculations predict that the orientation of the axial pyridine ligand(s) has a very minor influence on the calculated electronic structures and absorption spectra in the target systems.

  5. New Ru(II) Complex for Dual Activity: Photoinduced Ligand Release and (1)O2 Production.

    Loftus, Lauren M; White, Jessica K; Albani, Bryan A; Kohler, Lars; Kodanko, Jeremy J; Thummel, Randolph P; Dunbar, Kim R; Turro, Claudia


    The new complex [Ru(pydppn)(biq)(py)](2+) (1) undergoes both py photodissociation in CH3CN with Φ500 =0.0070(4) and (1)O2 production with ΦΔ =0.75(7) in CH3 OH from a long-lived (3) ππ* state centered on the pydppn ligand (pydppn=3-(pyrid-2-yl)benzo[i]dipyrido[3,2-a:2',3'-c]phenazine; biq = 2,2'-biquinoline; py=pyridine). This represents an order of magnitude decrease in the Φ500 compared to the previously reported model compound [Ru(tpy)(biq)(py)](2+) (3) (tpy=2,2':6',2''-terpyridine) that undergoes only ligand exchange. The effect on the quantum yields by the addition of a second deactivation pathway through the low-lying (3) ππ* state necessary for dual reactivity was investigated using ultrafast and nanosecond transient absorption spectroscopy, revealing a significantly shorter (3) MLCT lifetime in 1 relative to that of the model complex 3. Due to the structural similarities between the two compounds, the lower values of Φ500 and ΦΔ compared to that of [Ru(pydppn)(bpy)(py)](2+) (2) (bpy=2,2'-bipyridine) are attributed to a competitive excited state population between the (3) LF states involved in ligand dissociation and the long-lived (3) ππ* state in 1. Complex 1 represents a model compound for dual activity that may be applied to photochemotherapy.

  6. Effects of proton acceptors on formation of a non-heme iron(IV)-oxo complex via proton-coupled electron transfer.

    Nishida, Yusuke; Morimoto, Yuma; Lee, Yong-Min; Nam, Wonwoo; Fukuzumi, Shunichi


    Rates of formation of a non-heme iron(IV)-oxo complex, [Fe(IV)(O)(N4Py)](2+) (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), via electron-transfer oxidation of [Fe(III)(OH)(N4Py)](2+) in acetonitrile (MeCN) containing H2O (0.56 M) were accelerated as much as 390-fold by addition of proton acceptors such as CF3COO(-), TsO(-) (p-MeC6H4SO3(-)), NsO(-) (o-NO2C6H4SO3(-)), DNsO(-) (2,4-(NO2)2C6H3SO3(-)), and TfO(-) (CF3SO3(-)). The acceleration effect of proton acceptors increases with increasing basicity of the proton acceptors. The one-electron oxidation potential of [Fe(III)(OH)(N4Py)](2+) was shifted from 1.24 to 0.96 V vs SCE in the presence of TsO(-) (10 mM). The electron-transfer oxidation of Fe(III)-OH complex was coupled with the deprotonation process by proton acceptors in which deuterium kinetic isotope effects were observed when H2O was replaced by D2O.

  7. a New Digital Image Correlation Software for Displacements Field Measurement in Structural Applications

    Ravanelli, R.; Nascetti, A.; Di Rita, M.; Belloni, V.; Mattei, D.; Nisticó, N.; Crespi, M.


    Recently, there has been a growing interest in studying non-contact techniques for strain and displacement measurement. Within photogrammetry, Digital Image Correlation (DIC) has received particular attention thanks to the recent advances in the field of lowcost, high resolution digital cameras, computer power and memory storage. DIC is indeed an optical technique able to measure full field displacements and strain by comparing digital images of the surface of a material sample at different stages of deformation and thus can play a major role in structural monitoring applications. For all these reasons, a free and open source 2D DIC software, named py2DIC, was developed at the Geodesy and Geomatics Division of DICEA, University of Rome La Sapienza. Completely written in python, the software is based on the template matching method and computes the displacement and strain fields. The potentialities of Py2DIC were evaluated by processing the images captured during a tensile test performed in the Lab of Structural Engineering, where three different Glass Fiber Reinforced Polymer samples were subjected to a controlled tension by means of a universal testing machine. The results, compared with the values independently measured by several strain gauges fixed on the samples, demonstrate the possibility to successfully characterize the deformation mechanism of the investigated material. Py2DIC is indeed able to highlight displacements at few microns level, in reasonable agreement with the reference, both in terms of displacements (again, at few microns in the average) and Poisson's module.

  8. Synthesis,Crystal Structure and Magnetic Properties of a 1—D Polymer,[Cu(NITpPy)2(H2TCB)(H2O)]·2H2O

    WANG,Li-Ya; LI,Li-Cun; LIAO,Dai-Zheng; JIANG,Zong-Hui; YAN,Shi-Ping


    A novel complex[Cu(NITpPy)2(H2TCB)(H2O)]·2H2O (NITpPy=2-(pyrid-4''''''''-yl)-4,4,5,5-tetramethyl-1,3-dioxoimidazo-line;H2TCB=1,5-dicarboxybenzene carboxylic-2,4-diacid)has been synthesized and characterized by X-ray crystallography analysis.The crystal sturcture consists of infinite chains of Cu(NITpPy)2(H2O)units linked by H2TCB ligands.The complex crystallizes in triclinic system with space group P1-.Crystal data:a=1.0594(2)nm,b=1.3830(3)nm,c=1.5551(3)nm,a=67.75(3)°,β=89.83(3)°,γ=70.54(3)°.The variable magnetic susceptibility studies lead to magnetic coupling constant values of J1=-11.18cm-1(Cu-Rad)and J2=-4.06cm-1(Cu-Cu).

  9. A Photoactivatable Platinum(IV) Anticancer Complex Conjugated to the RNA Ligand Guanidinoneomycin.

    Shaili, Evyenia; Fernández-Giménez, Marta; Rodríguez-Astor, Savina; Gandioso, Albert; Sandín, Lluís; García-Vélez, Carlos; Massaguer, Anna; Clarkson, Guy J; Woods, Julie A; Sadler, Peter J; Marchán, Vicente


    A photoactivatable platinum(IV) complex, trans,trans,trans-[Pt(N3 )2 (OH)(succ)(py)2 ] (succ=succinylate, py=pyridine), has been conjugated to guanidinoneomycin to study the effect of this guanidinum-rich compound on the photoactivation, intracellular accumulation and phototoxicity of the pro-drug. Surprisingly, trifluoroacetic acid treatment causes the replacement of an azido ligand and the axial hydroxide ligand by trifluoroacetate, as shown by NMR spectroscopy, MS and X-ray crystallography. Photoactivation of the platinum-guanidinoneomycin conjugate in the presence of 5'-guanosine monophosphate (5'-GMP) led to the formation of trans-[Pt(N3 )(py)2 (5'-GMP)](+) , as does the parent platinum(IV) complex. Binding of the platinum(II) photoproduct {PtN3 (py)2 }(+) to guanine nucleobases in a short single-stranded oligonucleotide was also observed. Finally, cellular uptake studies showed that guanidinoneomycin conjugation improved the intracellular accumulation of the platinum(IV) pro-drug in two cancer cell lines, particularly in SK-MEL-28 cells. Notably, the higher phototoxicity of the conjugate in SK-MEL-28 cells than in DU-145 cells suggests a degree of selectivity towards the malignant melanoma cell line.

  10. Carbon nanotubes dispersed in aqueous solution by ruthenium(ii) polypyridyl complexes

    Huang, Kewei; Saha, Avishek; Dirian, Konstantin; Jiang, Chengmin; Chu, Pin-Lei E.; Tour, James M.; Guldi, Dirk M.; Martí, Angel A.


    . These studies show that the photoluminescence of both, that is, of the ruthenium complexes and of SWCNTs, are quenched when they interact with each other. Pump-probe transient absorption experiments were performed to shed light onto the nature of the photoluminescence quenching, showing carbon nanotube-based bands with picosecond lifetimes, but no new bands which could be unambigously assigned to photoinduced charge transfer process. Thus, from the spectroscopic data, we conclude that quenching of the photoluminescence of the ruthenium complexes is due to energy transfer to proximal SWCNTs. Electronic supplementary information (ESI) available: Absorption and emission spectra of RuPy2 with HiPco SWCNTs, 3-D emission spectra of RuPy1 and RuPy2/HiPco, representative AFM and TEM figures of RuPy1 and RuPy2 with SWCNTs, emission of RuPy2/SWCNTs, photophysical parameters for RuPy1 and RuPy2, picosecond transient absorption spectra of RuPy1, RuPy2, and lifetimes. Appendix 1. See DOI: 10.1039/c6nr02577c

  11. Ferrocenes as potential chemotherapeutic drugs: synthesis, cytotoxic activity, reactive oxygen species production and micronucleus assay.

    Pérez, Wanda I; Soto, Yarelys; Ortíz, Carmen; Matta, Jaime; Meléndez, Enrique


    Three new ferrocene complexes were synthesized with 4-(1H-pyrrol-1-yl)phenol group appended to one of the Cp ring. These are: 1,1'-4-(1H-pyrrol-1-yl)phenyl ferrocenedicarboxylate, ('Fc-(CO2-Ph-4-Py)2'), 1,4-(1H-pyrrol-1-yl)phenyl, 1'-carboxyl ferrocenecarboxylate ('Fc-(CO2-Ph-4-Py)CO2H') and 4-(1H-pyrrol-1-yl)phenyl ferroceneacetylate ('Fc-CH2CO2-Ph-4-Py'). The new species were characterized by standard analytical methods. Cyclic voltammetry experiments showed that Fc-CH2CO2-Ph-4-Py has redox potential very similar to the Fc/Fc(+) redox couple whereas Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H have redox potentials of over 400 mV higher than Fc/Fc(+) redox couple. The in vitro studies on Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H revealed that these two compounds have moderate anti-proliferative activity on MCF-7 breast cancer cell line. In contrast Fc-CH2CO2-Ph-4-Py which displayed low anti-proliferative activity. In the HT-29 colon cancer cell line, the new species showed low anti-proliferative activity. Cytokinesis-block micronucleus assay (CBMN) was performed on these ferrocenes and it was determined they induce micronucleus formation on binucleated cells and moderate genotoxic effects on the MCF-7 breast cancer cell line. There is a correlation between the IC50 values of the ferrocenes and the amount of micronucleus formation activity on binucleated cells and the reactive oxygen species (ROS) production on MCF-7 cell line.

  12. Three ion-pair complexes containing bis(maleonitriledithiolate)copper(II) anion and substituted 2-aminopyridinium cations: Syntheses, crystal structures, and magnetic properties

    Liu, Yin; Ou, Shu-Hua; Li, Jin-Ni; Liao, Xiao-Lan; Zheng, Xiao-Xu; Luo, Cui-Ping; Yang, Le-Min; Zhou, Jia-Rong; Ni, Chun-Lin


    Three new ion-pair complexes, [2-ClBz-2‧-NH2Py]2[Cu(mnt)2](1), [2-Cl-4-ClBz-2-NH2Py]2[Cu(mnt)2](2) and [2-Cl-4-BrBz-2‧-NH2Py]2[Cu(mnt)2]·C2H5OH(3) ([2-Cl-4-RBz-2‧-NH2Py]+ = 1-(2‧-chloro-4‧-Rbenzyl)-2-aminopyridinium, R = H, Cl, Br; mnt2- = maleonitriledithiolate), were synthesized and characterized by elemental analyses, IR, UV-visible, single crystal X-ray diffraction and magnetic measurements. Both 1 and 2 crystallize in the monoclinic space group P2(1)/c, and the [Cu(mnt)2]2- anions and the cations form a 1D network structure through the N-HṡṡṡN hydrogen bonds. While the anions in 3 form a ladder-like chain through the C-HṡṡṡN interactions between the [Cu(mnt)2]2- anions and CH3CH2OH molecules. Some weak interactions such as πṡṡṡπ, CuṡṡṡN, ClṡṡṡC, and C-HṡṡṡCl, O-HṡṡṡCl, C-HṡṡṡS, N-HṡṡṡO, N-HṡṡṡN and C-HṡṡṡN hydrogen bonds in three molecular solids generate further a 3D network structure. The magnetic measurement reveals that 1 shows a very weak ferromagnetic interaction, and 2 exhibits a transition from ferromagnetic to antiferromagnetic coupling about 15 K, while 3 shows an antiferromagnetic coupling feature with θ = -12.51 K when the temperature is lowered.

  13. Spontaneous resolution of a bis(eta(1)-methylcyclopentadienyl)zinc complex

    Olsson, S.; Lennartson, A.


    Two crystalline complexes of bis(eta(1)-methylcyclopentadienyl)zinc, [Zn(C5H4Me)(2)(py)(2)] (1), where py is pyridine, and [Zn(C5H4Me)(2)(teeda)], 2, where teeda is N,N,N',N'-tetraethylethylenediamine have been isolated. The crystal structures of 1 and 2 are the first crystal structures for Zn(C5H4......Me)(2) complexes reported in the literature; both structures display eta(1)-coordination of the methylcyclopentadienyl ring to zinc, and both compounds display chirogenic alpha-carbon atoms. While 1 forms racemic crystals, 2 undergoes spontaneous resolution and crystals of 2 are thus enantiomerically...

  14. ALLTEM System User’s Manual, Munitions Management Projects, ALLTEM Multi-Axis Electromagnetic Induction System Demonstration and Validation, Version 1.0


    7.1 Calling "python" from Run or a Command line should launch a Python interpreter ..106 7.2 Properly installed modules allow for importing numpy ...two modules need to be installed; these are called matplotlib and numpy . Binary releases are located in the bin directory of this release and are...called numpy -1.1.0-win32- superpack-python2.5.exe and matplotlib-0.98.1.win32-py2.5.exe. Both 2.5 and 2.4 versions are included in the bin folder

  15. The supplement of general solution for a Riccati differential equation%一类Riccati方程的通积分注记



    Using invariant of Riccati equation,the solution of Riccati equation,was given by FENG Lu-xiang,WEI Lie-ping in Journal of Baoji College of Arts and Science(Natural Science),2000,20(1),29-30,is supplemented,the unification solution is got.%利用Riccati方程y′=Py2+Qy+R的不变量解法,将冯录祥,魏列萍《一类Riccati方程的通积分》一文中Riccati方程解法补充完善,统一其中。


    О. Ciobanica


    Full Text Available The interaction of [Fe(DfgH2Py2] (where DfgH=monodeprotonated diphenylglyioxime, Py-pyridune and 1,3,5-triazine (Trz in chloroform resulted in a new coordination compound with the composition [Fe(DfgH2(Trz2]·2CHCl3 (1. The crystal structure of 1, determined by single crystal X-ray diffraction, revealed that Fe(II atom is coordinated by four oximic nitrogen atoms of two DfgH and two nitrogen atoms of two Trz ligands resulting in octahedral surrounding.

  17. Ruthenium-Aryloxide Catalysts for Olefin Metathesis

    Monfette, Sebastien; Blacquiere, Johanna M.; Conrad, Jay C.; Beach, Nicholas J.; Fogg, Deryn E.

    : Advances in design of ruthenium aryloxide catalysts for olefin metathesis are described. The target complexes are accessible on reaction of RuCl2(NHC)(py)2 (CHPh) (NHC - N-heterocyclic carbene) with electron-deficient, monodentate aryl- oxides, or aryloxides that yield small, rigid chelate rings. The best of these catalysts offer activity comparable to or greater than that of the parent chloride (Grubbs) systems in ring-closing metathesis (RCM). Preliminary studies of the electronic nature of the Ru-X bond suggest that the metal center is more electropositive in the aryloxide complexes than in the Grubbs systems.

  18. Cobalt (Ⅱ) Complexes of Dibenzoylmethane (Hdbm): Crystal Structures and Axial Metathetical Reaction of the Complexes with Pyridine or its Derivatives%钴的二苯甲酰甲烷配合物:晶体结构及其轴向置换反应

    卢会杰; 高洁; 杜晨霞; 樊耀亭; 侯红卫; 丁德刚; 翟俊玲


    Cobalt (Ⅱ) can form complexes with Hdbm in different environments. Hdbm reacted with cobalt nitrate to give complex 1 [Co(dbm)2 @ 2H2O]. When complex 1 reacted with pyridine, α-stilbazole or 4, 4'-bipyridine respectively, complex 2 [Co(DBM)2Py2] (Py= pyridine), 3 [Co(DBM)2Sbz2] (Sbz =α-stilbazole) or 4 [Co(DBM)2BPy] n was obtained in turn through metathetical reaction. The coordination modes are octahedral polyhedrons. In the crystal structures, the two dbms take the plane position and two other donor molecules take the axial position. CCDC: 196070 for complex 2; 186859 for complex 3.

  19. Synthesis of antipodal -trisubstituted meso-tetraphenylporphyrins and the crystal structure of hexaphenylporphinatozinc(II) bispyridinate complex

    Bhyrappa Puttaiah; Velkannan Veerapandian


    series of antipodal -trisubstituted meso-tetraphenylporphyrins, H2TPP(R)3 (R = CH3, Ph, PE, and 2′-thienyl) derivatives and their metal (Cu(II) and Zn(II)) complexes were synthesised and characterised by electronic absorption, 1H NMR spectroscopy and mass spectrometry. The magnitude of the red-shift in absorption bands in these free-base porphyrins depend on the nature of the substituent and follow the general trend: PE > 2′ > Ph > CH3. Synthesis, characterisation and crystal structure of 2,5,10,12,15,20-hexaphenylporphinato zinc(II) bispyridinate, ZnTPP(Ph)2(Py)2 complex is also reported. It shows planar geometry of the porphyrin ring with two -phenyls located at the antipodal 2,12-pyrrole positions. The two axially coordinated pyridine ring planes are oriented almost parallel to each other and they are in staggered conformation relative to opposite pyrrolic nitrogens. The normal-coordinate structural decomposition analysis of the ZnTPP(Ph)2(Py)2 complex revealed slight wave distortion of the macrocycle.

  20. Synthesis, crystal structure and characterization of new biologically active Cu(II) complexes with ligand derived from N-substituted sulfonamide



    A new N-sulfonamide ligand (HL1= N-(5-(4-methoxyphenyl)-[1,3,4]–thiadiazole–2-yl)-toluenesulfonamide)and two Cu(II) complexes, $[Cu(L1)­_{2}(py)_{2}]$ (C1) and $[Cu(L2)_{2}(py)_{2}(H_{2}O)]$ (C2) (HL2 = N-(5-(4-methylphenyl)-[1,3,4]–thiadiazole–2-yl)-benzenesulfonamide) were synthesized. The X-ray crystal structuresof the complexes were determined. In the complex C1, the Cu(II) ion is four-coordinated, forming a $CuN_{4}$ chromophore and in the complex C2, the Cu(II) ion is five-coordinated, forming a $CuN_{4}O$ chromophore. Theligand acts as monodentate, coordinating the Cu(II) ion through a single $N_{thiadiazole}$ atom. The molecules fromthe reaction medium (pyridine and water) are also involved in the coordination of the Cu(II) ion. The complexesC1 and C2 are square-planar and a slightly distorted square pyramidal, respectively. The compounds werecharacterized by FT-IR, electronic, EPR spectroscopic and magnetic methods. The nuclease binding activitystudies of the synthesized complexes confirm their capacity to cleave the DNA molecule. The cytotoxicitystudies were carried out on melanoma cell line WM35 which confirm that both compounds inhibit the growthof these cells. They have a higher activity compared to a platinum drug, carboplatin.

  1. Two Problems Concerning the Diophantine Equation x 2 -Dy 2 =±2%关于Diophantine方程x2-Dy2=±2的两个问题

    付瑞琴; 杨海


    设 D 是不含素因数 q ≡5或7(mod 8)的无平方因子正奇数,p 是大于3的奇素数。给出方程x 2-Dy 2=±2有正整数解(x,y )的充要条件,并且证明了当 p ≡17(mod 24)时,方程 x 2-3py 2=-2必有正整数解(x,y )。%Let D be a positive odd integer with square free and D has no primes q ≡5 or 7(mod 8),and let p be an odd prime with p > 3.In this paper,a necessary and sufficient condition for the equation x 2 -Dy 2 =±2 has positive integer solutions (x ,y )is given.Moreover,we prove that if p ≡17 (mod 24), then the equation x 2 -3py 2 =-2 must have positive integer solutions (x ,y ).

  2. X-ray Absorption Spectroscopic Studies of High-Spin Nonheme (Alkylperoxo)iron(III) Intermediates

    Shan,X.; Rohde, J.; Koehntop, K.; Zhou, Y.; Bukowski, M.; Costas, M.; Fujisawa, K.; Que, Jr., L.


    The reactions of iron(II) complexes [Fe(Tpt-Bu,i-Pr)(OH)] (1a, Tpt-Bu,i-Pr = hydrotris(3-tert-butyl-5-isopropyl-1-pyrazolyl)borate), [Fe(6-Me2BPMCN)(OTf)2] (1b, 6-Me2BPMCN = N,N'-bis((2-methylpyridin-6-yl)methyl)-N,N'-dimethyl-trans-1,2-diaminocyclohexane), and [Fe(L8Py2)(OTf)](OTf) (1c, L8Py2 = 1,5-bis(pyridin-2-ylmethyl)-1,5-diazacyclooctane) with tert-BuOOH give rise to high-spin FeIII-OOR complexes. X-ray absorption spectra (XAS) of these high-spin species show characteristic features, distinct from those of low-spin Fe-OOR complexes. These include (1) an intense 1s {yields} 3d preedge feature, with an area around 20 units, (2) an edge energy, ranging from 7122 to 7126 eV, that is affected by the coordination environment, and (3) a 1.86-1.96 Angstroms Fe-OOR bond, compared to the 1.78 Angstroms Fe-OOR bond in low-spin complexes. These unique features likely arise from a flexible first coordination sphere in those complexes. The difference in Fe-OOR bond length may rationalize differences in reactivity between low-spin and high-spin FeIII-OOR species.

  3. Kinetics and equilibria for the axial ligation of bromomethyl (aqua)cobaloxime with pyridines - Isolation characterization and DNA binding

    Kotha Laxma Reddy; K Ashwini Kumar; N Ravi Kumar Reddy; Penumaka Nagababu; A Panasa Reddy; S Satyanarayana


    The kinetics and equilibria for the axial ligation of pyridine and substituted pyridines to bromomethyl(aqua)cobaloxime have been measured spectrophotometrically in aqueous solutions of ionic strength 1.0 M (KC1) at 25°C as a function of H. The binding constants and rate of formation increase in the order 4-NH2Py 4-EtPy > 4-MePy > Py > 2-NH2Py > 2-EtPy. The data have been interpreted based on the basicity of the ligand, -back bonding from Co(III) → L and hard and soft interactions. The rate of substitution of H2O varies with the pKa of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state. We have investigated the DNA binding of bromomethyl(aqua)cobaloxime with DNA. Bromomethyl(ligand)cobaloximes were isolated and characterized by elemental analysis, IR and NMR (1H, 13C) spectra.

  4. Iridium Cyclooctene Complex That Forms a Hyperpolarization Transfer Catalyst before Converting to a Binuclear C-H Bond Activation Product Responsible for Hydrogen Isotope Exchange.

    Iali, Wissam; Green, Gary G R; Hart, Sam J; Whitwood, Adrian C; Duckett, Simon B


    [IrCl(COE)2]2 (1) reacts with pyridine (py) and H2 to form crystallographically characterized IrCl(H)2(COE)(py)2 (2). 2 undergoes py loss to form 16-electron IrCl(H)2(COE)(py) (3), with equivalent hydride ligands. When this reaction is studied with parahydrogen, 1 efficiently achieves hyperpolarization of free py (and nicotinamide, nicotine, 5-aminopyrimidine, and 3,5-lutudine) via signal amplification by reversible exchange (SABRE) and hence reflects a simple and readily available precatayst for this process. 2 reacts further over 48 h at 298 K to form crystallographically characterized (Cl)(H)(py)(μ-Cl)(μ-H)(κ-μ-NC5H4)Ir(H)(py)2 (4). This dimer is active in the hydrogen isotope exchange process that is used in radiopharmaceutical preparations. Furthermore, while [Ir(H)2(COE)(py)3]PF6 (6) forms upon the addition of AgPF6 to 2, its stability precludes its efficient involvement in SABRE.

  5. Synthesis and catalytic activity of metallo-organic complexes bearing 5-amino 2-ethylpyridine -2-carboximidate



    A series of copper, cobalt, nickel and manganese complexes were synthesized and characterized. Reaction of 5-amino-2-cyanopyridine with $ MCl_{2}$·x$H_{2}O$ (M: $Cu^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Mn^{2+})$ in anhydrous ethanol resulted in the formation of four complexes $[NH_{2}EtPyCuCl_{2}(CH_{3}OH)].H_{2}O 1$, $[(NH_{2}EtPyHCl)_{3}Co]$$(Cl)_{3}.3H_{2}O 2$, $[(NH_{2}EtPy)_{2}$ 2$(H_{2}O)Ni]$ $(Cl_{2})$ 3, and $[(NH_{2}EtPy)_{2}$ 2$(H_{2}O)$ Mn]$(Cl_{2})$ 4 $[NH_{2} EtPy=5-amino-oethylpyridine-2-carboximidate], respectively. The structures of these compounds were determined by X-raydiffraction, NMR and IR spectroscopy, and elemental analysis. Each complex was then used as a catalyst in the Henry reaction, and its catalytic activity was determined by 1H NMR. Good catalytic effects were achieved (69–87%).

  6. Photorelease of Pyridyl Esters in Organometallic Ru(II Arene Complexes

    Abraha Habtemariam


    Full Text Available New Ru(II arene complexes of formula [(η6-p-cymRu(N-N(X]2+ (where p-cym = para-cymene, N-N = 2,2'-bipyrimidine (bpm or 2,2'-bipyridine (bpy and X = m/p-COOMe-Py, 1–4 were synthesised and characterized, including the molecular structure of complexes [(η6-p-cymRu(bpy(m-COOMe-Py]2+ (3 and [(η6-p-cymRu(bpy (p-COOMe-Py]2+ (4 by single-crystal X-ray diffraction. Complexes 1–4 are stable in the dark in aqueous solution over 48 h and photolysis studies indicate that they can photodissociate the monodentate m/p-COOMe-Py ligands selectively with yields lower than 1%. DFT and TD-DFT calculations (B3LYP/LanL2DZ/6-31G** performed on singlet and triplet states pinpoint a low-energy triplet state as the reactive state responsible for the selective dissociation of the monodentate pyridyl ligands.

  7. Synthesis and Crystal Structure of a New One-dimensional Zn(II) Nitronyl Nitroxide Complex Bridged by Pyridine-2,4-dicarboxylate Anion

    GAO Dong-Zhao; LI Li-Cun; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping


    A new one-dimensional (1-D) Zn(II) nitronyl nitroxide complex bridged by pyri- dine-2,4-dicarboxylate anion, [Zn(NIT4Py)(2,4-PDA)(H2O)2]n (NIT4Py = 2-(4'-pyridyl)-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide and 2,4-PDA = pyridine-2,4-dicarboxylate anion), has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.834(2), b = 7.4376(10), c = 18.295(3) (A), β = 102.848(2)°, V = 2233.2(5)(A)3, C19H23N4O8Zn, Mr = 500.78, Dc = 1.489 g/cm3, μ(MoKα) = 1.152 mm-1, F(000) = 1036, Z = 4, the final R = 0.0390 and wR = 0.0915 for 3234 observed reflections. In the complex, each zinc(II) ion is six-coordinated by one nitrogen atom of the radical ligand (NIT4Py), one nitrogen atom and two oxygen atoms of two 2,4-PDA anions and two oxygen atoms of two water molecules. Each 2,4-PDA anion bridges two Zn(II) ions via a tridentate mode into a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

  8. Organometallic chemistry of chiral diphosphazane ligands: Synthesis and structural characterisation

    Kannan Raghuraman; Swadhin K Mandal; T S Venkatakrishnan; Setharampattu S Krishnamurthy; Munirathinam Nethaji


    The diphosphazane ligands of the type, (C20H12O2)PN(R)P(E)Y2 (R = CHMe2 or ()-∗CHMePh; E = lone pair or S; Y2 = O2C20H12 or Y = OC6H5 or OC6H4Me-4 or OC6H4OMe-4 or OC6H4Bu-4 or C6H5) bearing axially chiral 1,1'-binaphthyl-2,2'-dioxy moiety have been synthesised. The structure and absolute configuration of a diastereomeric palladium complex, [PdCl2{2-((O2C20H12)PN(()-∗CHMePh)PPh2}] has been determined by X-ray crystallography. The reactions of [CpRu(PPh3)2Cl] with various symmetrical and unsymmetrical diphosphazanes of the type, X2PN(R)PYY' (R = CHMe2 or ()-∗CHMePh; X = C6H5 or X2 = O2C20H12; Y = Y' = C6H5 or Y = C6H5, Y' = OC6H4Me-4 or OC6H3Me2-3,5 or N2C3HMe2-3,5) yield several diastereomeric neutral or cationic half-sandwich ruthenium complexes which contain a stereogenic metal center. In one case, the absolute configuration of a trichiral ruthenium complex, viz. [Cp∗Ru{2-Ph2PN(()-∗CHMePh)∗PPh (N2C3HMe2-3,5)}Cl] is established by X-ray diffraction. The reactions of Ru3(CO)12 with the diphosphazanes (C20H12O2)PN(R)PY2 (R = CHMe2 or Me; Y2=O2C20H12 or Y = OC6H5 or OC6H4Me-4 or OC6H4OMe-4 or OC6H4Bu-4 or C6H5) yield the triruthenium clusters [Ru3(CO)10{-(O2C20H12)PN(R)PY2}], in which the diphosphazane ligand bridges two metal centres. Palladium allyl chemistry of some of these chiral ligands has been investigated. The structures of isomeric 3-allyl palladium complexes, [Pd(3-1,3-R'2-C3H3){2-(rac)-(O2C20H12)PN(CHMe2)PY2}](PF6) (R' = Me or Ph; Y = C6H5 or OC6H5) have been elucidated by high field twodimensional NMR spectroscopic and X-ray crystallographic studies.

  9. A family of manganese rods: syntheses, structures, and magnetic properties.

    Rajaraman, Gopalan; Murugesu, Muralee; Sañudo, E Carolina; Soler, Monica; Wernsdorfer, Wolfgang; Helliwell, Madeleine; Muryn, Chris; Raftery, Jim; Teat, Simon J; Christou, George; Brechin, Euan K


    The reaction of the mixed-valent metal triangles [Mn(3)O(O(2)CR)(6)(py)(3)] (R = CH(3), Ph, C(CH(3))(3)) with the tripodal ligands H(3)thme (1,1,1-tris(hydroxymethyl)ethane) and H(3)tmp (1,1,1-tris(hydroxymethyl)propane) in MeCN, produces a family of manganese rodlike complexes whose structures are all derived from a series of edge-sharing triangles. Variable temperature direct current (dc) magnetic susceptibility data were collected for all complexes in the 1.8-300 K temperature range in fields up to 7.0 T. Complex 1, [Mn(12)O(4)(OH)(2)(PhCOO)(12)(thme)(4)(py)(2)], has an S = 7 ground state with the parameters g = 1.98 and D = -0.13 K. Complex 2, [Mn(8)O(4)((CH(3))(3)CCO(2))(10)(thme)(2)(py)(2)] has a ground state of S = 6, with g = 1.81 and D = -0.36 K. Complex 3, [Mn(7)O(2)(PhCO(2))(9)(thme)(2)(py)(3)], has a spin ground states of S = 7 with the parameters g = 1.78 and D = -0.20 K. The best fit for complex 4, [Mn(6)((CH(3))(3)CCO(2))(8)(tmp)(2)(py)(2)], gave a spin ground state of S = 3 with the parameters g = 1.73 and D = -0.75 K, but was of poorer quality than that normally obtained. The presence of multiple Mn(2+) ions in the structure of 4 leads to the presence of low-lying excited states with energy levels very close to the ground state, and in the case of complex 5, [Mn(6)(CH(3)CO(2))(6)(thme)(2)(H(2)tea)(2)], no satisfactory fit of the data was obtained. DFT calculations on 4 and 5 indicate complexes with spin ground states of S = 4 and S = 0 respectively, despite their topological similarities. Single-crystal hysteresis loop and relaxation measurements show complex 1 to be a SMM.

  10. Substitution reactions of diphenyl-2-pyridylphosphine with [(5-C5Me5)M(-Cl)Cl]2 (M = Rh or Ir) dimers: Isolation of mono-, di- and chelating complexes

    Padavattan Govindaswamy; Patrick J Carroll; Yurij A Mozharivskyj; Mohan Rao Kollipara


    The reaction of [{(h5-C5Me5)M(-Cl)Cl}2] {where M = Rh (1), Ir (2)} with functionalized phosphine viz., diphenyl-2-pyridylphosphine (PPh2Py) in dichloromethane solvent yield neutral 1-P-coordinated rhodium and iridium complexes [(5-C5Me5)RhCl2(1-P-PPh2Py)] 3 and [(5-C5Me5) IrCl2(1-P-PPh2Py)] 4. Reaction of complexes 1 and 2 with the ligand PPh2Py in methanol under reflux give bis-substituted complexes such as [(5-C5Me5)RhCl(1-P-PPh2Py)2]+ 5 and [(5-C5Me5)IrCl(1-P-PPh2Py)2]+ 6, whereas stirring in methanol at room temperature gives P-, N-chelating complexes of the type [(5-C5Me5)RhCl(2-P-N-PPh2Py)]+ 7 and [(5-C5Me5)IrCl(2-P-N-PPh2Py)]+ 8. Neutral 1-P-coordinated complexes [(5-C5Me5)RhCl2(1-P-PPh2Py)] 3 and [(5-C5Me5)IrCl2(1-P-PPh2Py)] 4 easily undergo conversion to the cationic P-, N-chelating complexes [(5-C5Me5)RhCl(2-P-N-PPh2Py)]+ 7 and [(5-C5Me5) IrCl(2-P, N-PPh2Py)]+ 8 on stirring in methanol at room temperature. These complexes are characterized by FT-IR and FT-NMR spectroscopy as well as analytical methods. The molecular structures of the representative complexes [(5-C5Me5)RhCl2(1-P-PPh2Py)] 3, [(5-C5Me5)IrCl2(1-P-PPh2Py)] 4 and hexafluorophosphate salt of complex [(5-C5Me5)IrCl(2-P-PPh2Py)2]+ 6 are established by singlecrystal X-ray diffraction methods.

  11. Structurally characterized luminescent lanthanide zinc carboxylate precursors for Ln-Zn-O nanomaterials.

    Boyle, Timothy J; Raymond, Rebecca; Boye, Daniel M; Ottley, Leigh Anna M; Lu, Ping


    A novel family of lanthanide zinc carboxylate compounds was synthesized, characterized (structural determination and luminescent behavior), and investigated for utility as single-source precursors to Ln-Zn-O nanoparticles. Carboxylic acids [H-ORc = H-OPc (H-O(2)CCH(CH(3))(2), H-OBc (H-O(2)CC(CH(3))(3), H-ONc (H-O(2)CCH(2)C(CH(3))(3))] were individually reacted with diethyl zinc (ZnEt(2)) to yield a set of previously unidentified zinc carboxylates: (i) [Zn(mu-ORc)(3)Zn(mu-ORc)](n) [ORc = OPc (1), ONc (2)], (ii) [(py)Zn](2)(mu-ORc)(4) [ORc = OBc (3), ONc (4), and py = pyridine], or (iii) Zn(ORc)(2)(solv)(2) [ORc/solv = OPc/py (5), O(c)Nc/H(2)O (6) (O(c)Rc = chelating)]. Introduction of lanthanide cation [Ln[N(SiMe(3))(2)](3), ZnEt(2), and HOBc in py] yielded the mixed cationic species structurally characterized as: (i) (O(c)Bc)Ln[(mu-OBc)(3)Zn(py)](2) [Ln = Pr (7), Nd (8), Sm (9)] or (ii) (py)(2)Zn(mu-OBc)(3)Ln(O(c)Bc)(2)(py) [Ln = Tb (10), Dy (11), Er (12), Y (13), Yb (14)]. Exploration of alternative starting materials [Ln(NO(3))(3).nH(2)O, Zn(O(2)CCH(3))(2), HOBc in py] led to the isolation of (NO(3)(c))Ln[(mu-OBc)(3)Zn(py)](2) [Ln = La (15), Ce (16), Pr (17), Nd (18), Sm (19), Eu (20), Gd (21), Tb (22) Dy (23), and Er (24); NO(3)(c) = chelating]. The UV-vis spectra of 7-24 revealed standard absorption spectra for the Ln cations. Representative compounds were used to generate nanoparticles from an established 1,4-butanediol-based solution precipitation route. The nanoproducts isolated adopted either a mixed zincite/lanthanum oxide (18n or 22n) or pure zincite (8n or 10n) phase dependent on NO(3) or OBc moiety. Fluorescence was not observed for any of these nanomaterials possibly due to phase separation, low crystallinity, surface traps, and/or quenching based on elevated Ln cation content.

  12. Synthesis and Uncommon Structural Characterization of Novel Zinc and Cadmium Complexes with Imino Nitroxide Radical

    WANG Shu-Ping; GAO Dong-Zhao; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping


    Two novel complexes {[Zn(IM4py)2(tp)(H2O)]·2H2O}n 1 and {[Cd(IM4py)2(tp)- (H2O)]·1.25H2O}n 2 (IM4py=2-(4'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and tp=terephthalate dianion) have been synthesized and characterized by elemental analyses, IR spectrum and single-crystal X-ray diffraction. Crystal data for complex 1: monoclinic, space group C2/c, a=20.648(7), b=12.130(4), c=14.036(4) (A), β=106.351(5)°, C32H42N6O9Zn, Mr=720.09, V=3373.3(2) (A)3, Z=4, Dc=1.418 g/cm3, μ(MoKα)= 0.790 mm-1, F(000)=1512, the final R=0.0407 and Wr=0.0894 for 3480 independent reflections with Rint=0.0432. Crystal data for complex 2: monoclinic, space group C2/c, a=21.332(6), b=12.063(3), c=14.246(4) (A), β=106.704(4)°, C32H40.50N6O8.25Cd, Mr=753.60, V=3511.2(2) (A)3, Z=4, Dc=1.426 g/cm3, μ(MoKα)= 0.679 mm-1, F(000)=1554, the final R=0.0419 and Wr=0.0961 for 3627 independent reflections with Rint=0.0440. The framework structures of complexes 1 and 2 are 3-D networks via the hydrogen bonds among 1-D chains. The notable characteristics of the two complexes are that the coordination polyhedron of Zn(Ⅱ) adopts a rare distorted five-coordinate square pyramidal geometry in 1, and the Cd(Ⅱ) complex exhibits an unusual distorted seven-coordinate pentagonal bipyramid in 2.

  13. Platinum-group element concentrations in pyrite from the Main Sulfide Zone of the Great Dyke of Zimbabwe

    Piña, R.; Gervilla, F.; Barnes, S.-J.; Oberthür, T.; Lunar, R.


    The Main Sulfide Zone (MSZ) of the Great Dyke of Zimbabwe hosts the world's second largest resource of platinum-group elements (PGE) after the Bushveld Complex in South Africa. The sulfide assemblage of the MSZ comprises pyrrhotite, pentlandite, chalcopyrite, and minor pyrite. Recently, several studies have observed in a number of Ni-Cu-PGE ore deposits that pyrite may host significant amounts of PGE, particularly Pt and Rh. In this study, we have determined PGE and other trace element contents in pyrite from the Hartley, Ngezi, Unki, and Mimosa mines of the Great Dyke by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Based on the textures and PGE contents, two types of pyrite can be differentiated. Py1 occurs as individual euhedral or subhedral grains or clusters of crystals mostly within chalcopyrite and pentlandite, in some cases in the form of symplectitic intergrowths, and is PGE rich (up to 99 ppm Pt and 61 ppm Rh; 1.7 to 47.1 ppm Ru, 0.1 to 7.8 ppm Os, and 1.2 to 20.2 ppm Ir). Py2 occurs as small individual euhedral or subhedral crystals within pyrrhotite, pentlandite, and less frequently within chalcopyrite and silicates and has low PGE contents (<0.11 ppm Pt, <0.34 ppm Rh, <2.5 ppm Ru, <0.37 ppm Ir, and <0.40 ppm Os). Py1 contains higher Os, Ir, Ru, Rh, and Pt contents than the associated pyrrhotite, pentlandite, and chalcopyrite, whereas Py2 has similar PGE contents as coexisting pyrrhotite and pentlandite. Based on the textural relationships, two different origins are attributed for each pyrite type. Py1 intergrowth with pentlandite and chalcopyrite is inferred to have formed by late, low temperature (<300 °C) decomposition of residual Ni-rich monosulfide solid solution, whereas Py2 is suggested to have formed by replacement of pyrrhotite and pentlandite caused by late magmatic/hydrothermal fluids.

  14. Femtosecond Excited State Dynamics of Size Selected Neutral Molecular Clusters.

    Montero, Raúl; León, Iker; Fernández, José A; Longarte, Asier


    The work describes a novel experimental approach to track the relaxation dynamics of an electronically excited distribution of neutral molecular clusters formed in a supersonic expansion, by pump-probe femtosecond ionization. The introduced method overcomes fragmentation issues and makes possible to retrieve the dynamical signature of a particular cluster from each mass channel, by associating it to an IR transition of the targeted structure. We have applied the technique to study the nonadiabatic relaxation of pyrrole homoclusters. The results obtained exciting at 243 nm, near the origin of the bare pyrrole electronic absorption, allow us to identify the dynamical signature of the dimer (Py)2, which exhibits a distinctive lifetime of τ1 ∼ 270 fs, considerably longer than the decays recorded for the monomer and bigger size clusters (Py)n>2. A possible relationship between the measured lifetime and the clusters geometries is tentatively discussed.

  15. Experimental investigation of the role of the triplet pairing in the superconducting spin-valve effect

    Leksin, P. V.; Kamashev, A. A.; Garif'yanov, N. N.; Validov, A. A.; Fominov, Ya. V.; Schumann, J.; Kataev, V. E.; Büchner, B.; Garifullin, I. A.


    An important role of the morphology of a superconducting layer in the superconducting spin-valve effect has been established. The triplet pairing induced by the superconductor/ferromagnet proximity effect has been experimentally investigated for samples CoO x /Py1/Cu/Py2/Cu/Pb (where Py = Ni0.81Fe0.19) with a smooth superconducting layer. The optimization of the parameters of this structure has demonstrated a complete switching between the normal and superconducting states with a change in the relative orientation of magnetizations of the ferromagnetic layers from the antiparallel to orthogonal orientation. A pure triplet contribution has been observed for the sample with a permalloy layer thickness at which the superconducting spin-valve effect vanishes. A direct comparison of the experimental data with the theoretical calculation of the temperature of the transition to the superconducting state has been performed for the first time.

  16. Poly[tris(2,5-dimethylbenzene-1,4-dicarboxylatobis(pyridinetrizinc(II

    Li Nie


    Full Text Available The asymmetric unit of the title polymeric compound, [Zn3(C10H8O43(C5H5N2]n or [Zn3(dmbdc3(py2]n (dmbdc = 2,5-dimethylbenzenedicarboxylate; py = pyridine contains two Zn(II ions, one of which is located on an inversion centre, one and a half 2,5-dimethylbenzenedicarboxylate ligands and one pyridine ligand. Each ZnO6 octahedron is sandwiched between two ZnO4N square-pyramids, forming a trinuclear zinc secondary building unit (SBU; each SBU is further linked by six 2,5-dimethylbenzenedicarboxylate ligands with six adjacent trinuclear zinc SBU's, forming a two-dimensional layer structure with a (3,6 net. One of the three zinc ions is octahedrally coordinated and the other two are square-pyramidally coordinated. The coordination modes for 2,5-dimethylbenzenedicarboxylates are bis(bidentate or bidentate-tridentate.


    Sutopo Hadi


    Full Text Available he synthesis of two stable platinum(IV complexes containing methoxo ligand, [Pt(CH32(OCH3(OHpy2] (1 and fac-[Pt(CH32(OCH3(H2O3] (2, has been successfully performed. Complex 1 was prepared by oxidative addition reaction of cis-[Pt(CH32py2] with dry methanol, and a subsequent reaction of 1 with 70 % HClO4 in water produced the platinum complex 2. The stability of complex 2 in acidic aqueous solution was investigated and monitored with 1H and 195Pt NMR. The platinum complex 2 was found to be quite stable toward hydrolysis and no -hydride elimination was observed. Keywords: Methoxoplatinum(IV, NMR, complex stability, hydrolysis

  18. ROMP-Derived cyclooctene-based monolithic polymeric materials reinforced with inorganic nanoparticles for applications in tissue engineering

    Franziska Weichelt


    Full Text Available Porous monolithic inorganic/polymeric hybrid materials have been prepared via ring-opening metathesis copolymerization starting from a highly polar monomer, i.e., cis-5-cyclooctene-trans-1,2-diol and a 7-oxanorborn-2-ene-derived cross-linker in the presence of porogenic solvents and two types of inorganic nanoparticles (i.e., CaCO3 and calcium hydroxyapatite, respectively using the third-generation Grubbs initiator RuCl2(Py2(IMesH2(CHPh. The physico-chemical properties of the monolithic materials, such as pore size distribution and microhardness were studied with regard to the nanoparticle type and content. Moreover, the reinforced monoliths were tested for the possible use as scaffold materials in tissue engineering, by carrying out cell cultivation experiments with human adipose tissue-derived stromal cells.

  19. Synthesis and characterization of oxovanadium (IV dithiocarbamates with pyridine

    Antonio L. Doadrio


    Full Text Available We report the synthesis and study of a new series of oxovanadium (IV dithiocarbamate adducts and derivatives with pyridine and cyclohexyl, di-iso-butyl, di-n-propyl, anilin, morpholin, piperidin and di-iso-propyl amines. The complexes have been characterized by analytical, magnetochemical, IR, visible-UV spectral and thermal studies, and are assigned the formulas [VO(L2].py, where L=cyclohexyl, di-iso-butyl, di-n-propyl, anilin dithiocarbamate and [VO(OH(L(py2]OH.H2O (L=morpholin, piperidin and di-iso-propyl dithiocarbamate. The effect of the adduct formation on the pV=0 bound is discussed in terms of the IR (V=O, V-S and V-N stretching frequencies and electronic spectra (d-d transitions.

  20. The high-temperature expansion of the classical Ising model with Sz2 term

    M.T. Thomaz


    Full Text Available We derive the high-temperature expansion of the Helmholtz free energy up to order β17 of the one-dimensional spin-S Ising model, with single-ion anisotropy term, in the presence of a longitudinal magnetic field. We show that the values of some thermodynamical functions for the ferromagnetic models, in the presence of a weak magnetic field, are not small corrections to their values with h=0. This model with S=3 was applied by Kishine et al. [J.-i. Kishine et al., Phys. Rev. B, 2006, 74, 224419] to analyze experimental data of the single-chain magnet [Mn (saltmen]2 [Ni(pac2 (py2] (PF62 for T<40 K. We show that for T<35 K the thermodynamic functions of the large-spin limit model are poor approximations to their analogous spin-3 functions.

  1. Hysteretic Spin Crossover in Two-Dimensional (2D) Hofmann-Type Coordination Polymers.

    Liu, Wei; Wang, Lu; Su, Yu-Jun; Chen, Yan-Cong; Tucek, Jiri; Zboril, Radek; Ni, Zhao-Ping; Tong, Ming-Liang


    Three new two-dimensional (2D) Hofmann-type coordination polymers with general formula [Fe(3-NH2py)2M(CN)4] (3-NH2py = 3-aminopyridine, M = Ni (1), Pd (2), Pt (3)) have been synthesized. Magnetic susceptibility measurements show that they exhibited cooperative spin crossover (SCO) with remarkable hysteretic behaviors. Their hysteresis widths are 25, 37, and 30 K for 1-3, respectively. The single-crystal structure of 1 suggest that the pseudo-octahedral Fe sites are equatorially bridged by [M(CN)4](2-) to form 2D grids and axially coordinated by 3-NH2py ligands. The intermolecular interactions between layers (the offset face-to-face π···π interactions, hydrogen bonds, and weak N(amino)···Ni(II) contacts) together with the covalent bonds bridged by [M(CN)4](2-) units are responsible to the significant cooperativity.

  2. 8-Ranks of Class Groups of Quadratic Number Fields and Their Densities

    Qin YUE


    For F=Q(√εpq1/2),ε∈{±1,±2},primes-p≡q≡1 mod 4,we give the necessary and sufficient conditions for 8-ranks of narrow class groups of F equal to 1 or 2 such that we can calculate their densities.All results are stated in terms of congruence relations of p,q modulo 2n,the quartic residue smbol(p/q)4 and binary quadratic forms such as qh(-2p)/4=x2+2py2,where h(-2p)is the class number of Q(√-2p1/2).The results are very useful for numerical computations.

  3. Synthesis, structure and magnetic properties of 5-(4-Sulfophenylazo) salicylate-bridged 1D coordination polymers containing linear trinuclear metal clusters

    Liu, Hong; Song, Li-jun; Ju, Zhan-feng; Li, Wei; Zhang, Jie


    Three new trinuclear metal complexes with an azobenzene-containing ligand [M 3(Sasa) 2(Py) 2(H 2O) 8] (Na 2HSasa = 5-(4-Sulfophenylazo) salicylic acid disodium salt; Py = pyridine; M = Cu, Co, Zn), are synthesized through the interface diffusion and structurally characterized by single crystal X-ray diffraction, XRPD analysis and spectral methods. The metal ions in distorted octahedral coordination environments are connected by Sasa ligands to form 1D coordination polymer chain containing the linear trinuclear units with single syn-anti carboxylate bridges. The extensive hydrogen bonding interactions hold these chains together into 3D supramolecular network. Weak antiferromagnetic interactions between adjacent metal ions with J = -1.85 cm -1 and J = -2.81 cm -1 dominate the magnetic properties of Cu(II) and Co(II) complexes, separately.

  4. Synthesis and characterization of polymeric azido Zn(II) and Ni(II) complexes based on 3-hydroxypyridine

    Mautner, Franz A.; Berger, Christian; Domian, Elisabeth; Fischer, Roland C.; Massoud, Salah S.


    The synthesis and structural characterization of two new complexes catena-[Ni(3-O-py)(3-HO-py)2(μ1,3-N3)(H2O)] (1) and catena-[Zn(μ-3-O-py)(μ1,1-N3)] (2), where 3-HO-py = 3-hydroxypyridine, are reported. The complexes were characterized by the elemental microanalyses, IR, and X-ray crystallography and by UV-Vis spectroscopy for complex 1. Single crystal X-ray crystallography revealed the polymeric nature of the complexes: 1 as 1D with a single EE azide bridging, and 2 as 2D with μ(O,O‧,N) bridging of the deprotonated 3-O-py anions and di-EO azide groups, respectively. In 1 the neutral and deprotonated 3-hydroxypyridine molecules act only as N-terminal ligands. The emission spectral properties of the Zn(II) complex were investigated.

  5. Tunable Crystal-to-Crystal Phase Transition in a Cadmium Halide Chain Polymer

    Ulli Englert


    Full Text Available The chain polymer [{Cd(μ-X2py2}1∞] (X = Cl, Br; py = pyridine undergoes a fully reversible phase transition between a monoclinic low-temperature and an orthorhombic high-temperature phase. The transformation can be directly monitored in single crystals and can be confirmed for the bulk by powder diffraction. The transition temperature can be adjusted by tuning the composition of the mixed-halide phase: Transition temperatures between 175 K up to the decomposition of the material at ca. 350 K are accessible. Elemental analysis, ion chromatography and site occupancy refinements from single-crystal X-ray diffraction agree with respect to the stoichiometric composition of the samples.

  6. Efficient Pathway for the Preparation of Aryl(isoquinoline)iodonium(III) Salts and Synthesis of Radiofluorinated Isoquinolines.

    Yuan, Zheliang; Cheng, Ran; Chen, Pinhong; Liu, Guosheng; Liang, Steven H


    Iodonium compounds play a pivotal role in (18) F-fluorination of radiopharmaceuticals containing non-activated arenes. However, preparation of these species is limited to oxidation conditions or exchange with organometallics that are prepared from aryl halides. Herein we describe a novel "one-pot" process to assemble aryl(isoquinoline)iodonium salts in 40-94 % yields from mesoionic carbene silver complex and Aryl-I-Py2 (OTf)2 . The method is general, practical, and compatible with well-functionalized molecules as well as useful for the preparation of a wide range of (18) F-labeled isoquinolines resulting in up to 92 % radiochemical conversion. As proof of concept, a fluorinated isoquinoline alkaloid, (18) F-aspergillitine is prepared in 10 % isolated radiochemical yield from the corresponding phenyl(aspergillitine)iodonium salt.

  7. 4,6-connected fsb topology networks obtained through two-step crystal engineering of decorated trigonal prismatic nodes

    Schoedel, Alexander


    A two-step crystal engineering strategy has been utilized to synthesize a new and versatile class of metal-organic materials, the first to exhibit 4,6-connected fsb topology. The new fsb networks are constructed from simple and inexpensive nodes (4-connected Zn(CO2)(py)2 tetrahedra; 6-connected Cr(μ3-O)(RCO2)6 trigonal prisms) and linker ligands (isonicotinate and various dicarboxylates). Further, since interpenetration is precluded, they can exhibit extra-large void volumes. These fsb nets are prototypal for what should ultimately become a large family of related structures given the ready availability of functionalized and/or expanded variants of both linker ligands. The fsb nets described herein therefore represent platforms or blueprints for a new family of ultrahigh surface area porous materials. © 2014 American Chemical Society.

  8. C-C bond formation and related reactions at the CNC backbone in (smif)FeX (smif = 1,3-di-(2-pyridyl)-2-azaallyl): dimerizations, 3 + 2 cyclization, and nucleophilic attack; transfer hydrogenations and alkyne trimerization (X = N(TMS)2, dpma = (di-(2-pyridyl-methyl)-amide)).

    Frazier, Brenda A; Williams, Valerie A; Wolczanski, Peter T; Bart, Suzanne C; Meyer, Karsten; Cundari, Thomas R; Lobkovsky, Emil B


    Molecular orbital analysis depicts the CNC(nb) backbone of the smif (1,3-di-(2-pyridyl)-2-azaallyl) ligand as having singlet diradical and/or ionic character where electrophilic or nucleophilic attack is plausible. Reversible dimerization of (smif)Fe{N(SiMe3)2} (1) to [{(Me3Si)2N}Fe]2(μ-κ(3),κ(3)-N,py2-smif,smif) (2) may be construed as diradical coupling. A proton transfer within the backbone-methylated, and o-pyridine-methylated smif of putative ((b)Me2(o)Me2smif)FeN(SiMe3)2 (8) provides a route to [{(Me3Si)2N}Fe]2(μ-κ(4),κ(4)-N,py2,C-((b)Me,(b)CH2,(o)Me2(smif)H))2 (9). A 3 + 2 cyclization of ditolyl-acetylene occurs with 1, leading to the dimer [{2,5-di(pyridin-2-yl)-3,4-di-(p-tolyl-2,5-dihydropyrrol-1-ide)}FeN(SiMe3)2]2 (11), and the collateral discovery of alkyne cyclotrimerization led to a brief study that identified Fe(N(SiMe3)2(THF) as an effective catalyst. Nucleophilic attack by (smif)2Fe (13) on (t)BuNCO and (2,6-(i)Pr2C6H3)NCO afforded (RNHCO-smif)2Fe (14a, R = (t)Bu; 14b, 2,6-(i)PrC6H3). Calculations suggested that (dpma)2Fe (15) would favorably lose dihydrogen to afford (smif)2Fe (13). H2-transfer to alkynes, olefins, imines, PhN═NPh, and ketones was explored, but only stoichiometric reactions were affected. Some physical properties of the compounds were examined, and X-ray structural studies on several dinuclear species were conducted.

  9. A Mn₁₅ single-molecule magnet consisting of a supertetrahedron incorporated in a loop.

    Moushi, Eleni E; Masello, Antonio; Wernsdorfer, Wolfgang; Nastopoulos, Vassilios; Christou, George; Tasiopoulos, Anastasios J


    Two new Mn(15) clusters consisting of a supertetrahedron which is incorporated in a loop are reported. The reactions of [Mn(O(2)CEt)(2)]·2H(2)O with the diols 1,3-propanediol (H(2)pd) or 2-methyl-1,3-propanediol (H(2)mpd) in the presence of KX (X = CN(-), Cl(-), Br(-), NO(3)(-), ClO(4)(-), OCN(-), SCN(-)) afforded compounds [Mn(15)K(mu(4)-O)(4)(O(2)CEt)(11)(pd)(12)(py)(2)] (1) and [Mn(15)K(mu(4)-O)(4)(O(2)CEt)(11)(mpd)(12)(py)(2)] (2). The structural core of 1 and 2 consists of a Mn(11) loop and a Mn(9)K supertetrahedron sharing a Mn(5) triangle. To the best of our knowledge, the structural motif of a supertetrahedron incorporated in a loop appears for the first time in metal cluster chemistry. Variable-temperature, solid-state direct current (dc) magnetic susceptibility studies in the 300-5 K range showed that the chi(M)T value increases with decreasing T suggesting the existence of predominant ferromagnetic exchange interactions and a relatively large ground state spin. This was confirmed by field-variable temperature magnetization measurements which were fitted using a matrix diagonalization method to give S approximately 23/2, g = 1.92(1) and D = -0.071(2) cm(-1). In addition, compound 1 displays frequency-dependent alternating current (ac) signals suggesting single-molecule magnetism (SMM) behaviour. This was proven by magnetization vs. dc field sweeps on single-crystals of 1·0.7py·1.3MeCN, which displayed sweep rate- and temperature-dependent hysteresis loops.

  10. A two-step spin transition with a disordered intermediate state in a new two-dimensional coordination polymer.

    Rodríguez-Velamazán, J Alberto; Castro, Miguel; Palacios, Elías; Burriel, Ramón; Kitazawa, Takafumi; Kawasaki, Takeshi


    The two-dimensional (2D) polymeric spin crossover (SCO) compound Fe(py)2[Ag(CN)2]2 has been synthesized. The compound shows a two-step spin transition detected by magnetic, heat capacity, and X-ray diffraction measurements. The magnetic moment shows a high-temperature step (step 1) occurring at 146.3 K without hysteresis, while the low-temperature step (step 2) happens at 84 K on cooling and 98.2 K on heating. These measurements reveal a large amount of residual high spin (HS) species (23%) and that HS state trapping occurs at cooling rates of around 1 K min(-1) or higher. The two-step behavior has been confirmed by heat capacity, which gives, for steps 1 and 2, respectively, DeltaH1 = 3.33 kJ mol(-1), DeltaS1 = 22.6 J mol(-1) K(-1), and DeltaH2 = 1.51 kJ mol(-1), DeltaS2 = 15.7 J mol(-1) K(-1). For step 2 a hysteresis of 10 K has been determined with dynamic measurements. Powder X-ray diffraction at room temperature shows that the compound is isostructural to Cd(py)2[Ag(CN)2]2 previously reported. Powder X-ray diffraction indicates that there is only one crystallographic site for iron(II) in the whole temperature range, confirmed by Mössbauer spectroscopy. The X-ray diffraction study at different temperatures do not show any superstructure in the region between the transitions, discarding a crystallographic phase transition as the origin of the two-step behavior. However, an unexpected increase of the thermal factor is detected on lowering the temperature and considered as a manifestation of a disordered state between the two steps, consisting of a mixing of HS and LS species without long-range order.

  11. Metal–organic frameworks assembled from lanthanide and 2,5-pyridinedicaboxylate with cubane-like [Ln{sub 4}(OH){sub 4}] building units

    Abdelbaky, Mohammed S.M. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain); Amghouz, Zakariae, E-mail: [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain); Servicios Científico-Técnicos, University of Oviedo—CINN, Oviedo 33006 (Spain); Fernández-Zapico, Eva; García-Granda, Santiago; García, José R. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain)


    Lanthanide–organic frameworks based on 2,5-pyridinedicaboxylate (25p) ligand, formulated as [Yb{sub 4}(OH){sub 4}(25p){sub 4}(H{sub 2}O){sub 3}]·H{sub 2}O (25pYb), [Y{sub 4}(OH){sub 4}(25p){sub 4}(H{sub 2}O){sub 3}]·H{sub 2}O (25pY-1) and [Y{sub 6}(OH){sub 8}(25p){sub 5}(H{sub 2}O){sub 2}] (25pY-2), have been obtained as single phases under hydrothermal conditions. 25pYb and 25pY-1 are isostructural, and crystallize in the triclinic space group, P-1, with a=8.6075(5) Å, b=14.8478(7) Å, c=15.9164(9) Å, α=86.277(4)°, β=80.196(5)°, γ=81.785(4)°, and a=8.7166(6) Å, b=14.966(1) Å, c=15.966(1) Å, α=86.260(6)°, β=80.036(6)°, γ=81.599(6)°, respectively. 25pY-2 crystallizes in the monoclinic space group, P2{sub 1}/c, with a=24.9117(17) Å, b=13.7340(8) Å, c=14.3385(10) Å, β=100.551(7)°. 25pYb and 25pY-2 have been structurally characterized by single-crystal X-ray diffraction. The 25pYb structure is based on tetranuclear cubane-like [Yb{sub 4}(OH){sub 4}]{sup 8+} clusters, which are interconnected to eight neighbouring clusters through teen surrounding 25p ligands leading to neutral 3D framework, while the structure of 25pY-2 is based on two independent cuban-like [Y{sub 4}(OH){sub 4}]{sup 8+} clusters, which are joined together through Y1 cation leading to the formation of hexanuclear [Y{sub 6}(OH){sub 8}]{sup 10+} clusters, which in turn are joined via Y2 cation resulting in infinite inorganic chain extending along c-axis, and each chain is interconnected to six adjacent chains through 25p ligands leading finally to 3D framework. The luminescence properties of Eu{sup 3+} and Tb{sup 3+} doped 25pY-1 and 25pY-2 compounds have also been investigated. All materials has been characterized by powder X-ray diffraction, thermal analyses (TG–SDTA–MS), FTIR spectroscopy, C–H–N elemental analysis, scanning electron microscopy (SEM-EDX), and powder X-ray thermodiffraction. - Graphical abstract: Nowadays, lanthanide–organic frameworks (LOFs) attract tremendous attention due to the unique characteristic of lanthanide cations, such as variable coordination numbers and geometries which often lead to novel complex structures, and also to their magnetic and photoluminescence properties. Herein, three LOFs formulated as [Ln{sub 4}(OH){sub 4}(25p){sub 4}(H{sub 2}O){sub 3}]·H{sub 2}O (Ln=Y, Yb) and [Y{sub 6}(OH){sub 8}(25p){sub 5}(H{sub 2}O){sub 2}] have been obtained by hydrothermal method and characterized, and the photoluminescence properties of the Eu and Tb doped compounds are discussed. - Highlights: • Three novel LnOFs has been synthesized and characterized. • Crystal structures are based on tetranuclear cuban-like [Ln{sub 4}(OH){sub 4}]{sup 8+} clusters. • 25pYb and 25pY-1 are based on isolated [Ln{sub 4}(OH){sub 4}]{sup 8+} clusters. • 25pY-2 is based on infinite inorganic chains built up from [Y{sub 4}(OH){sub 4}]{sup 8+} clusters. • Photoluminescence studies show strong red and green light emissions.

  12. Synthesis, structure determination, and spectroscopic/computational characterization of a series of Fe(II)-thiolate model complexes: implications for Fe-S bonding in superoxide reductases.

    Fiedler, Adam T; Halfen, Heather L; Halfen, Jason A; Brunold, Thomas C


    A combined synthetic/spectroscopic/computational approach has been employed to prepare and characterize a series of Fe(II)-thiolate complexes that model the square-pyramidal [Fe(II)(N(His))(4)(S(Cys))] structure of the reduced active site of superoxide reductases (SORs), a class of enzymes that detoxify superoxide in air-sensitive organisms. The high-spin (S = 2) Fe(II) complexes [(Me(4)cyclam)Fe(SC(6)H(4)-p-OMe)]OTf (2) and [FeL]PF(6) (3) (where Me(4)cyclam = 1,4,8,11-tetramethylcyclam and L is the pentadentate monoanion of 1-thioethyl-4,8,11-trimethylcyclam) were synthesized and subjected to structural, magnetic, and electrochemical characterization. X-ray crystallographic studies confirm that 2 and 3 possess an N(4)S donor set similar to that found for the SOR active site and reveal molecular geometries intermediate between square pyramidal and trigonal bipyramidal for both complexes. Electronic absorption, magnetic circular dichroism (MCD), and variable-temperature variable-field MCD (VTVH-MCD) spectroscopies were utilized, in conjunction with density functional theory (DFT) and semiemperical INDO/S-CI calculations, to probe the ground and excited states of complexes 2 and 3, as well as the previously reported Fe(II) SOR model [(L(8)py(2))Fe(SC(6)H(4)-p-Me)]BF(4) (1) (where L(8)py(2) is a tetradentate pyridyl-appended diazacyclooctane macrocycle). These studies allow for a detailed interpretation of the S-->Fe(II) charge transfer transitions observed in the absorption and MCD spectra of complexes 1-3 and provide significant insights into the nature of Fe(II)-S bonding in complexes with axial thiolate ligation. Of the three models investigated, complex 3 exhibits an absorption spectrum that is particularly similar to the one reported for the reduced SOR enzyme (SOR(red)), suggesting that this model accurately mimics key elements of the electronic structure of the enzyme active site; namely, highly covalent Fe-S pi- and sigma-interactions. These spectral

  13. Systematic differences in electrochemical reduction of the structurally characterized anti-cancer platinum(IV) complexes [Pt{((p-HC6F4)NCH2)2}-(pyridine)2Cl2], [Pt{((p-HC6F4)NCH2)2}(pyridine)2(OH)2], and [Pt{((p-HC6F4)NCH2)2}(pyridine)2(OH)Cl].

    Guo, Si-Xuan; Mason, Dayna N; Turland, Susan A; Lawrenz, Eric T; Kelly, Lance C; Fallon, Gary D; Gatehouse, Bryan M; Bond, Alan M; Deacon, Glen B; Battle, Andrew R; Hambley, Trevor W; Rainone, Silvina; Webster, Lorraine K; Cullinane, Carleen


    The putative platinum(IV) anticancer drugs, [Pt{((R)NCH(2))(2)}(py)(2)XY] (X,Y=Cl, R=p-HC(6)F(4) (1a), C(6)F(5) (1b); X,Y=OH, R=p-HC(6)F(4) (2); X=Cl, Y=OH, R=p-HC(6)F(4) (3), py = pyridine) have been prepared by oxidation of the Pt(II) anticancer drugs [Pt{((R)NCH(2))(2)}(py)(2)] (R=p-HC(6)F(4) (4a) or C(6)F(5) (4b)) with PhICl(2) (1a,b), H(2)O(2) (2) and PhICl(2)/Bu(4)NOH (3). NMR spectroscopy and the X-ray crystal structures of 1b, 2 and 3 show that they have octahedral stereochemistry with the X,Y ligands in the trans-position. The net two electron electrochemical reduction of 1a, 2 and 3 has been studied by voltammetric, spectroelectrochemical and bulk electrolysis techniques in acetonitrile. NMR and other data reveal that reduction of 1a gives pure 4a via the elimination of both axial chloride ligands. In the case of 2, one end of the diamide ligand is protonated and the resulting -NH(p-HC(6)F(4)) group dissociated giving a [Pt{N(p-HC(6)F(4))CH(2)CH(2)NH(p-HC(6)F(4))}] arrangement, one pyridine ligand is lost and a hydroxide ion retained in the coordination sphere. Intriguingly, in the case of reduction of 3, a 50% mixture of the reduction products of pure 1a and 2 is formed. The relative ease of reduction is 1>3>2. Testing of 1a, 2 and 3 against L1210 and L1210(DDP) (DDP = cis-diamine-dichloroplatinum(II)) mouse leukaemia cells shows all to be cytotoxic with IC(50) values of 1.0-3.5 μM. 2 and 3 are active in vivo against AHDJ/PC6 tumor line when delivered in peanut oil despite being hard to reduce electrochemically, and notably are more active than 4a delivered in this medium whilst comparable with 4a delivered in saline/Tween. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Mineral weathering in acid saprolites from subtropical, southern Brazil Intemperismo subtropical de minerais em saprolitos ácidos do Sul do Brasil

    Celso Augusto Clemente


    Full Text Available Because weathering of minerals releases chemical elements into the biogeochemical cycle, characterization of their weathering products helps to better model groundwater quality, formation of secondary minerals and nutrient flux through the trophic chain. Based on microscopic and elemental analyses, weathering of riodacite from Serra Geral formation was characterized and weathering paths proposed. Three weathering paths of plagioclase phenocrystals were identified: plagioclase to gibbsite (Pg1; plagioclase to gels and gibbsite (Pg2; and plagioclase to gels, gibbsite and kaolinite (Pg3. Pyroxenes weathered to smectite and goethite (Py1, or to goethite and gibbsite (Py2, and magnetite weathered directly into iron oxides. Rock matrix comprises 90% of rock volume, and weathered to kaolinite and gibbsite, which explains why these minerals were the most abundant in the weathering products of these saprolites.O intemperismo de minerais primários disponibiliza elementos químicos no ciclo biogeoquímico, que por sua vez influencia a qualidade da água subterrânea, formação de minerais secundários e o fluxo de nutrientes na cadeia trófica. Com base na análise microscópica e elemental, o intemperismo de riodacito da formação Serra Geral foi caracterizado e mecanismos de intemperismo propostos. Três processos principais de intemperismo de fenocristais de plagioclásios foram identificados: plagioclásio para gibbsita (Pg1; plagioclásio para gel e gibbsita (Pg2, e plagioclásio para gel, gibbsita e caulinita (Pg3. Piroxênios intemperizaram-se para esmectita e goetita (Py1, ou para goethita e gibbsita (Py2, e magnetita intemperizou-se para óxidos de ferro. A matriz da rocha compõe 90% do volume total, e intemperiza-se para caulinita e gibbsita, o que explica a abundância destes minerais nos produtos de intemperismo destes saprolitos.

  15. Additional serine/threonine phosphorylation reduces binding affinity but preserves interface topography of substrate proteins to the c-Cbl TKB domain.

    Qingxiang Sun

    Full Text Available The E3-ubiquitin ligase, c-Cbl, is a multi-functional scaffolding protein that plays a pivotal role in controlling cell phenotype. As part of the ubiquitination and downregulation process, c-Cbl recognizes targets, such as tyrosine kinases and the Sprouty proteins, by binding to a conserved (NX/RpY(S/TXXP motif via its uniquely embedded SH2 domain (TKB domain. We previously outlined the mode of binding between the TKB domain and various substrate peptide motifs, including epidermal growth factor receptor (EGFR and Sprouty2 (Spry2, and demonstrated that an intrapetidyl hydrogen bond forms between the (pY-1 arginine or (pY-2 asparagine and the phosphorylated tyrosine, which is crucial for binding. Recent reports demonstrated that, under certain types of stimulation, the serine/threonine residues at the pY+1 and/or pY+2 positions within this recognition motif of EGFR and Sprouty2 may be endogenously phosphorylated. Using structural and binding studies, we sought to determine whether this additional phosphorylation could affect the binding of the TKB domain to these peptides and consequently, whether the type of stimulation can dictate the degree to which substrates bind to c-Cbl. Here, we show that additional phosphorylation significantly reduces the binding affinity between the TKB domain and its target proteins, EGFR and Sprouty2, as compared to peptides bearing a single tyrosine phosphorylation. The crystal structure indicates that this is accomplished with minimal changes to the essential intrapeptidyl bond and that the reduced strength of the interaction is due to the charge repulsion between c-Cbl and the additional phosphate group. This obvious reduction in binding affinity, however, indicates that Cbl's interactions with its TKB-centered binding partners may be more favorable in the absence of Ser/Thr phosphorylation, which is stimulation and context specific in vivo. These results demonstrate the importance of understanding the environment in which certain residues are phosphorylated, and the necessity of including this in structural investigations.

  16. Electronic Structure and Reactivity of a Well-Defined Mononuclear Complex of Ti(II).

    Wijeratne, Gayan B; Zolnhofer, Eva M; Fortier, Skye; Grant, Lauren N; Carroll, Patrick J; Chen, Chun-Hsing; Meyer, Karsten; Krzystek, J; Ozarowski, Andrew; Jackson, Timothy A; Mindiola, Daniel J; Telser, Joshua


    A facile and high-yielding protocol to the known Ti(II) complex trans-[(py)4TiCl2] (py = pyridine) has been developed. Its electronic structure has been probed experimentally using magnetic susceptibility, magnetic circular dichroism, and high-frequency and high-field electron paramagnetic resonance spectroscopies in conjunction with ligand-field theory and computational methods (density functional theory and ab initio methods). These studies demonstrated that trans-[(py)4TiCl2] has a (3)Eg ground state (dxy(1)dxz,yz(1) orbital occupancy), which, as a result of spin–orbit coupling, yields a ground-state spinor doublet that is EPR active, a first excited-state doublet at ∼60 cm(–1), and two next excited states at ∼120 cm(–1). Reactivity studies with various unsaturated substrates are also presented in this study, which show that the Ti(II) center allows oxidative addition likely via formation of [Ti(η(2)-R2E2)Cl2(py)n] E = C, N intermediates. A new Ti(IV) compound, mer-[(py)3(η(2)-Ph2C2)TiCl2], was prepared by reaction with Ph2C2, along with the previously reported complex trans-(py)3Ti═NPh(Cl)2, from reaction with Ph2N2. Reaction with Ph2CN2 also yielded a new dinuclear Ti(IV) complex, [(py)2(Cl)2Ti(μ2:η(2)-N2CPh2)2Ti(Cl)2], in which the two Ti(IV) ions are inequivalently coordinated. Reaction with cyclooctatetraene (COT) yielded a new Ti(III) complex, [(py)2Ti(η(8)-COT)Cl], which is a rare example of a mononuclear “piano-stool” titanium complex. The complex trans-[(py)4TiCl2] has thus been shown to be synthetically accessible, have an interesting electronic structure, and be reactive toward oxidation chemistry.

  17. Oxo-group-14-element bond formation in binuclear uranium(V) Pacman complexes.

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


    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}(OUOSiMe3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide "ate" complex [Li(py)2][(OUO)(N")3] (N" = N(SiMe3)2) with the polypyrrolic macrocycle H4L or the mononuclear uranyl (VI) Pacman complex [UO2(py)(H2L)], 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 [{(R3Sn)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.

  18. Ab initio MO study on equilibrium bond distance between Fe and pyridine in bis(pyridine)(porphinato) iron for various electronic states

    Saito, Minoru; Kashiwagi, Hiroshi


    For bis(pyridine)(porphinato) iron [FeP(py)2], a correlation between the iron electronic state and the equilibrium Fe-Npy distance was investigated. Potential energy curves as a function of the Fe-Npy distance were calculated for low-spin, intermediate-spin, and high-spin states of the ferric and ferrous ions by the ab initio SCF MO method. The equilibrium Fe-Npy distances were obtained from the potential curves. The values obtained for the ferric low-spin and high-spin states were in good agreement with the experimental values for Fe(III)(OEP)(3-Clpy)2 within the differences, ±0.05 Å. The following significant features were found. The equilibrium distance is elongated by the occupation of the 3dz2 orbital and is shortened by the oxidation of the iron atom. The distance and the force constant for the symmetrical py-Fe-py stretching are strongly correlated with the overlap population between the 3dz2 orbital and pyridine-nitrogen orbitals.

  19. The Use of Differential EXAFS Analysis for the determination of Small Structural Differences between two closely-related Ruthenium Complexes

    Gianolio, D.; Borfecchia, E.; Garino, C.; Ruiu, T.; Lamberti, C.; Salassa, L.


    X-ray Absorption Spectroscopy (XAS) is a sensitive and powerful technique in revealing the structure of a material, providing as well high accuracy on interatomic distances. Nevertheless, when dealing with systems that differ only by small structural features, a standard data analysis might be unable of discriminating between such differences. A differential approach was proposed by Bressler, Chergui, and co-workers [2003, Phys. Rev. Lett. 90, 047403][2006, J. Phys. Chem B, 110, 14035][2009 Angew. Chem., Int. Ed. 48 2711] to solve this problem and differentiate between excited and unexcited state structures during pump-and-probe transient XAS experiments. In this contribution, we apply the differential data analysis procedure to the study of two closely-related molecular complexes, namely cis-[Ru(bpy)2(py)2]2+ and cis-[Ru(bpy)2(py)(H2O)]2+, characterized under static conditions. It is herein demonstrated that the method, based on a direct fit of differential curves, is able to reveal the small differences present between the two structures which, conversely, could not be resolved by standard EXAFS fitting of full spectra.

  20. Molecular recognition and self-assembly special feature: Self-assembled biomimetic [2Fe2S]-hydrogenase-based photocatalyst for molecular hydrogen evolution.

    Kluwer, A M; Kapre, R; Hartl, F; Lutz, M; Spek, A L; Brouwer, A M; van Leeuwen, P W N M; Reek, J N H


    The large-scale production of clean energy is one of the major challenges society is currently facing. Molecular hydrogen is envisaged as a key green fuel for the future, but it becomes a sustainable alternative for classical fuels only if it is also produced in a clean fashion. Here, we report a supramolecular biomimetic approach to form a catalyst that produces molecular hydrogen using light as the energy source. It is composed of an assembly of chromophores to a bis(thiolate)-bridged diiron ([2Fe2S]) based hydrogenase catalyst. The supramolecular building block approach introduced in this article enabled the easy formation of a series of complexes, which are all thoroughly characterized, revealing that the photoactivity of the catalyst assembly strongly depends on its nature. The active species, formed from different complexes, appears to be the [Fe(2)(micro-pdt)(CO)(4){PPh(2)(4-py)}(2)] (3) with 2 different types of porphyrins (5a and 5b) coordinated to it. The modular supramolecular approach was important in this study as with a limited number of building blocks several different complexes were generated.

  1. Influence of synthesis conditions on complexation of Cu (II) with O,N,O tridentate hydrazone ligand. X-ray diffraction and spectroscopic investigations

    Repich, H. H.; Orysyk, S. I.; Orysyk, V. V.; Zborovskii, Yu. L.; Melnyk, A. K.; Trachevskyi, V. V.; Pekhnyo, V. I.; Vovk, M. V.


    Four novel Cu2+ coordination compounds with a (E)-N‧-(2-hydroxybenzylidene)-2-phenylacetohydrazide (HBPAH, H2L) have been synthesized and characterized by single crystal X-ray diffraction method, IR, UV-Vis and EPR spectroscopy. In all obtained compounds the ligand is coordinated in typical O,N,O-tridentate chelate manner. It has been shown that synthesis conditions have a great influence on a structure of resulting complex compounds. Depending on starting Cu2+ compounds, concentration of reagents, pH and the presence of secondary ligands the HBPAH coordinates as a neutral molecule, mono- or dianion with formation of four different complexes: [Cu(HL)(H2L)]NO3 (I), [Cu(HL)Cl] (II), [Cu2(HL)2Cl2] (III) and [Cu2(L)2Py2] (IV). Complex I is interesting by the presence of two differently coordinated ligand molecules. Mononuclear complex compound II and its dimeric analogue III were obtained from the same reagents: CuCl2 and HBPAH but in different reaction conditions. In dimeric complex IV the HBPAH molecules are coordinated as dianions in imidol tautomeric form, the pyridine molecules act as secondary ligands complementing the coordination polyhedra of Cu2+ ions. Study of UV-Vis and EPR spectra of complex compounds I-IV in solutions showed that all the complexes undergo partial solvolysis upon dissolution.

  2. 宝石鲈无乳链球菌的分离鉴定及耐药性分析%Isolation, Identification and Drug Susceptibility Analysis of Streptococcus agalactiae in Scortum barcoo

    黄木珍; 黎炯; 潘忠超; 石和荣


    2013年高温季节在广东广州2个养殖场患病宝石鲈(Scortum barcoo)病灶处共分离到2株细菌Py1和Py2.宝石鲈攻毒试验结果显示2株分离菌均具有较强毒力(半致死量分别为7.42×106和1.72×106 CFU/mL),且都对罗非鱼具有高度感染性(半致死量分别为3.39×106和8.66×105 CFU/mL).经ATB生化鉴定及cfb基因序列分析,确定分离株为无乳链球菌(Streptococcus agalactiae),并对其进行了相关药敏试验检测,以期为该病的预防提供参考.

  3. Effect of particle pinch on the fusion performance and profile features of an international thermonuclear experimental reactor-like fusion reactor

    Wang, Shijia; Wang, Shaojie


    The evolution of the plasma temperature and density in an international thermonuclear experimental reactor (ITER)-like fusion device has been studied by numerically solving the energy transport equation coupled with the particle transport equation. The effect of particle pinch, which depends on the magnetic curvature and the safety factor, has been taken into account. The plasma is primarily heated by the alpha particles which are produced by the deuterium-tritium fusion reactions. A semi-empirical method, which adopts the ITERH-98P(y,2) scaling law, has been used to evaluate the transport coefficients. The fusion performances (the fusion energy gain factor, Q) similar to the ITER inductive scenario and non-inductive scenario (with reversed magnetic shear) are obtained. It is shown that the particle pinch has significant effects on the fusion performance and profiles of a fusion reactor. When the volume-averaged density is fixed, particle pinch can lower the pedestal density by ˜30 % , with the Q value and the central pressure almost unchanged. When the particle source or the pedestal density is fixed, the particle pinch can significantly enhance the Q value by 60 % , with the central pressure also significantly raised.

  4. Dithiafulvene-based organic sensitizers using pyridine as the acceptor for dye-sensitized solar cells

    Cheng, Jun; Cao, Yaxiong; Liang, Xiaozhong; Zheng, Jingxia; Zhang, Fang [Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Wei, Shuxian; Lu, Xiaoqing [College of Science, China University of Petroleum, Qingdao, Shandong 266555 (China); Guo, Kunpeng, E-mail: [Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Yang, Shihe, E-mail: [Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)


    Three dithiafulvene-based metal-free organic sensitizers all using pyridine as the acceptor but with different π-bridges of phenyl (DTF-Py1), thienyl (DTF-Py2) and phenyl-thienyl (DTF-Py3) have been designed, synthesized and used as photosensitizers for dye-sensitized solar cells (DSCs). Introducing thienyl unit into the π-bridge, as well as extension of the π-bridge can dramatically improve their light harvesting ability and suppress the electron recombination, thus uplifting the performance of DSCs. The overall power conversion efficiency of DSC based on DTF-Py3 shows the highest efficiency of 2.61% with a short-circuit photocurrent density of 7.99 mA cm{sup -2}, an open-circuit photovoltage of 630 mV, and a fill factor of 0.52, under standard global AM 1.5 solar light condition. More importantly, the long-term stability of the DTF-Py3 based DSCs under 500 h light-soaking has been demonstrated. - Highlights: • Dithiafulvene sensitizers using pyridine ring as the acceptor were synthesized for the first time. • The power conversion efficiency of 2.61% was obtained for DTF-Py3 sensitized cell. • DTF-Py3 loaded TiO{sub 2} film shows improved light harvesting ability and suppressed electron recombination.

  5. Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol

    Brown, Margaret E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Mukhopadhyay, Aindrila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Keasling, Jay D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Horsholm (Denmark)


    In this paper, we report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. Finally, in the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.

  6. Excited state intramolecular proton transfer (ESIPT) in six-coordinated zinc(ii)-quinoxaline complexes with ligand hydrogen bonds: their fluorescent properties sensitive to axial positions.

    Sakai, Ken-Ichi; Takahashi, Sami; Kobayashi, Ataru; Akutagawa, Tomoyuki; Nakamura, Takayoshi; Dosen, Masaaki; Kato, Masako; Nagashima, Umpei


    Zinc(ii)-quinoxaline complexes, [Zn(hqxc)(2)(py)(2)] and [Zn(hqxc)(2)(DMSO)(2)] (hqxc = 3-hydroxy-2-quinoxalinecarboxylate, py = pyridine, DMSO = dimethyl sulfoxide), were prepared and characterized by X-ray crystallography and fluorescence spectroscopy. In both complexes, the zinc ion is six-coordinated by two equatorial bidentate hqxc ligands with an intramolecular hydrogen bond and two axial monodentate ligands such as pyridine or DMSO. In spite of similar coordination geometries, there is a remarkable difference between their solid-state fluorescent properties. The pyridine complex is strongly fluorescent (fluorescence quantum yield Phi = 0.22), giving rise to a significantly Stokes-shifted spectrum. From its thin film photopumped by a nitrogen gas laser, amplified spontaneous emission was observed. These results suggest that the fluorescence occurs by way of excited-state intramolecular proton-transfer (ESIPT) in the hydrogen bond of hqxc. On the other hand, the DMSO complex shows fluorescent intensity (Phi = 0.08) lower than that of the pyridine complex, and shows normal emission in addition to ESIPT emission. From IR measurements for these complexes, it is concluded that axial ligands influence the hydrogen bond strength of the equatorial hqxc ligand via zinc and thus the ESIPT efficiency.

  7. Dynamical control of the spin transition inside the thermal hysteresis loop of a spin-crossover single crystal

    Boukheddaden, Kamel, E-mail: [GEMaC, Université de Versailles St-Quentin, 45 Avenue des Etats Unis, 78035 Versailles (France); Sy, Mouhamadou; Paez-Espejo, Miguel [GEMaC, Université de Versailles St-Quentin, 45 Avenue des Etats Unis, 78035 Versailles (France); Slimani, Ahmed [Laboratoire des matériaux ferroélectriques, Département de Physique, Faculté des Sciences de Sfax, Route de la Soukra km 3.5 BP 1171, 3018 Sfax (Tunisia); Varret, François [GEMaC, Université de Versailles St-Quentin, 45 Avenue des Etats Unis, 78035 Versailles (France)


    We have succeeded to achieve experimentally, using an adapted optical microscopy setup, the reversible control of the front transformation between the low-spin (LS)–high-spin (HS) interface in the spin-crossover (SC) single crystal [{Fe(NCSe)(py)_2}{sub 2}(m-bpypz)] undergoing a first-order transition at 112 K with a 7 K hysteresis width. For that, we first generate a phase separation state (a HS/LS interface at equilibrium) inside the hysteresis loop by tuning the light intensity of the microscope. In the second step, this intensity is monitored in such a way to drive, through a photo-heating process, the interface motion. This photo-control is found to be reversible, accurate and requiring a very small amount of energy. In addition the integrity of the crystal is maintained even after a large number of cycling. The experimental observations, are well described as a reaction diffusion process accounting for the front propagation and the photo-heating effects.

  8. Ultrafast electronic and vibrational dynamics in brominated aluminum corroles: Energy relaxation and triplet formation

    T. Stensitzki


    Full Text Available We combined femtosecond (fs VIS pump–IR probe spectroscopy with fs VIS pump–supercontinuum probe spectroscopy to characterize the photoreaction of the hexacoordinated Al(tpfc-Br8(py2 in a comprehensive way. Upon fs excitation at ∼400 nm in the Soret band, the excitation energy relaxes with a time constant of (250 ± 80 fs to the S2 and S1 electronic excited states. This is evident from the rise time of the stimulated emission signal in the visible spectral range. On the same time scale, narrowing of broad infrared signals in the C=C stretching region around 1500 cm−1 is observed. Energy redistribution processes are visible in the vibrational and electronic dynamics with time constants between ∼2 ps and ∼20 ps. Triplet formation is detected with a time constant of (95 ± 3 ps. This is tracked by the complete loss of stimulated emission. Electronic transition of the emerging triplet absorption band overlaps considerably with the singlet excited state absorption. In contrast, two well separated vibrational marker bands for triplet formation were identified at 1477 cm−1 and at 1508 cm−1. These marker bands allow a precise identification of triplet dynamics in corrole systems.

  9. Mixed Ligand Complexes of N-Methyl-N-phenyl Dithiocarbamate: Synthesis, Characterisation, Antifungal Activity, and Solvent Extraction Studies of the Ligand.

    Ekennia, Anthony C; Onwudiwe, Damian C; Ume, Cyril; Ebenso, Eno E


    A series of mixed ligand dithiocarbamate complexes with a general formula [ML2(py)2], where M = Mn(II), Co(II), Ni(II), and Cu(II), py = pyridine, and L = N-methyl-N-phenyl dithiocarbamate have been prepared and characterised by elemental analysis, FTIR and Uv spectroscopy, magnetic moment, and thermogravimetric and conductance analysis. The infrared spectra showed that symmetrical bidentate coordination occurred with the dithiocarbamate moiety through the sulfur atoms, while neutral monodentate coordination occurred through the nitrogen atom for the pyridine molecule in the complexes. The electronic spectra, elemental analysis, and magnetic moment results proved that the complexes adopted octahedral geometry. The conductance measurement showed that the complexes are nonelectrolytes proving their nonionic nature. The compounds were screened for three human pathogenic fungi: Aspergillus flavus, Aspergillus niger, and Candida albicans. The cobalt complex showed the best antifungal activity among the test compounds. Liquid-liquid extractive abilities of the ligand towards copper and nickel ions in different solvent media were investigated. The ligand showed a strong binding affinity towards the metals ions with an extractive efficiency of about 99%.

  10. Synthesis, characterization, cytotoxicity and antimicrobial studies on bis(N-furfuryl-N-(2-phenylethyl)dithiocarbamato-S,S')zinc(II) and its nitrogen donor adducts.

    Rani, Palanisamy Jamuna; Thirumaran, Subbiah


    [Zn(fpedtc)2] (1), [Zn(fpedtc)2(py)] (2), [Zn(fpedtc)2(1,10-phen)] (3) and [Zn(fpedtc)2(2,2'-bipy)] (4) (where fpedtc = N-furfuryl-N-(2-phenylethyl)dithiocarbamate, py = pyridine, 1,10-phen = 1,10-phenanthroline and 2,2'-bipy = 2,2'-bipyridine) were synthesized. Characterization of the complexes were achieved by IR and NMR ((1)H and (13)C) spectra and in addition, for 2 and 3, by X-ray crystallography. Single crystal X-ray structural analysis of 2 and 3 showed that complex 2 is almost half way between trigonal bipyramidal and square pyramidal and complex 3 has a distorted octahedral geometry. Zn-N distances in 2 is shorter than that found in a six coordinate complex 3 due to the change in coordination number. These complexes were also screened for in vitro antibacterial and antifungal activities and significant activities have been found. In vitro cytotoxic activity of all the synthesized complexes was evaluated on HeLa cell line. Complex 1 exhibits maximum inhibitory effect at a concentration of 40 μg mL(-1) on HeLa cell line.

  11. Equilibrium thermodynamics to form a rhodium formyl complex from reactions of CO and H2: metal σ donor activation of CO.

    Imler, Gregory H; Zdilla, Michael J; Wayland, Bradford B


    A rhodium(II) dibenzotetramethylaza[14]annulene dimer ([(tmtaa)Rh]2) (1) reacts with CO and H2 in toluene and pyridine to form equilibrium distributions with hydride and formyl complexes ((tmtaa)Rh-H (2); (tmtaa)Rh-C(O)H (3)). The rhodium formyl complex ((tmtaa)Rh-C(O)H) was isolated under a CO/H2 atmosphere, and the molecular structure was determined by X-ray diffraction. Equilibrium constants were evaluated for reactions of (tmtaa)Rh-H with CO to produce formyl complexes in toluene (K2(298 K)(tol) = 10.8 (1.0) × 10(3)) and pyridine (K2(298 K)(py) = 2.2 (0.2) × 10(3)). Reactions of 1 and 2 in toluene and pyridine are discussed in the context of alternative radical and ionic pathways. The five-coordinate 18-electron Rh(I) complex ([(py)(tmtaa)Rh(I)](-)) is proposed to function as a nucleophile toward CO to give a two-electron activated bent Rh-CO unit. Results from DFT calculations on the (tmtaa)Rh system correlate well with experimental observations. Reactions of 1 with CO and H2 suggest metal catalyst design features to reduce the activation barriers for homogeneous CO hydrogenation.

  12. catena-Poly[[[iodidocopper(I]-{μ-N-[(pyridin-2-yl-κNmethylidene]pyridin-3-amine-κ2N3:N1}] acetonitrile hemisolvate

    Ali Mahmoudi


    Full Text Available In the asymmetric unit of the title polymeric complex, {[CuI(C11H9N3]·0.5CH3CN}n, there are two CuI atoms, two N-[(pyridin-2-yl-κNmethylidene]pyridin-3-amine (PyPy ligands and two I atoms. Both CuI atoms have a distorted tetrahedral geometry, each being coordinated by one I atom, two N atoms of one PyPy ligand and one N atom from an adjacent PyPy ligand. In the crystal, infinite helical chains of [Cu2(PyPy2]n are formed propagating along the b axis. These chains are linked via weak C—H...I hydrogen bonds and π–π stacking interactions [shortest centroid–centroid distance = 3.2727 (14 Å]. During the refinement, electron-density peaks were located that were believed to be highly disordered solvent molecules (possibly acetonitrile. The SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155] indicated there were solvent cavities with a total volume of 196 Å3 containing approximately 60 electrons per unit cell, which equated to one molecule of acetonitrile per asymmetric unit.

  13. Minimum dimension of an ITER like Tokamak with a given Q

    Johner, J


    The minimum dimension of an ITER like tokamak with a given amplification factor Q is calculated for two values of the maximum magnetic field in the superconducting toroidal field coils. For ITERH-98P(y,2) scaling of the energy confinement time, it is shown that for a sufficiently large tokamak, the maximum Q is obtained for the operating point situated both at the maximum density and at the minimum margin with respect to the H-L transition. We have shown that increasing the maximum magnetic field in the toroidal field coils from the present 11.8 T to 16 T would result in a strong reduction of the machine size but has practically no effect on the fusion power. Values obtained for {beta}{sub N} are found to be below 2. Peak fluxes on the divertor plates with an ITER like divertor and a multi-machine expression for the power radiated in the plasma mantle, are below 10 MW/m{sup 2}.

  14. Magnetic vortex nucleation/annihilation in artificial-ferrimagnet microdisks

    Lapa, Pavel N.; Ding, Junjia; Phatak, Charudatta; Pearson, John E.; Jiang, J. S.; Hoffmann, Axel; Novosad, Valentine


    The topological nature of the magnetic-vortex state gives rise to peculiar magnetization reversal observed in magnetic microdisks. Interestingly, magnetostatic and exchange, energies which, drive this reversal can be effectively controlled in artificial ferrimagnet heterostructures composed of rare-earth and transition metals. [Py(t)/Gd(t)]25 (t = 1 or 2 nm) superlattices demonstrate a pronounced change of the magnetization and exchange stiffness in a 10-300 K temperature range as well as very small magnetic anisotropy. Due to these properties, the magnetization of cylindrical microdisks composed of these artificial ferrimagnets can be transformed from the vortex to uniformly magnetized states in a permanent magnetic field by changing the temperature. We explored the behavior of magnetization in 1.5-μm [Py(t)/Gd(t)]25 (t = 1 or 2 nm) disks at different temperatures and magnetic fields and observed that due to the energy barrier separating vortex and uniformly magnetized states, the vortex nucleation and annihilation occur at different temperatures. This causes the temperature dependences of the magnetization in these Py/Gd disks to demonstrate a unique hysteretic behavior in a narrow temperature range. It was discovered that for the [Py(2 nm)/Gd(2 nm)]25 microdisks, the vortex can be metastable within a certain temperature range.

  15. Structural, MALDI-TOF-MS, magnetic and spectroscopic studies of new dinuclear copper(II), cobalt(II) and zinc(II) complexes containing a biomimicking μ-OH bridge.

    Núñez, Cristina; Bastida, Rufina; Macías, Alejandro; Valencia, Laura; Neuman, Nicolás I; Rizzi, Alberto C; Brondino, Carlos D; González, Pablo J; Capelo, José Luis; Lodeiro, Carlos


    The Py(2)N(4)S(2) octadentate coordinating ligand afforded dinuclear cobalt, copper and zinc complexes and the corresponding mixed metal compounds. The overall geometry and bonding modes have been deduced on the basis of elemental analysis data, MALDI-TOF-MS, IR, UV-vis and EPR spectroscopies, single-crystal X-Ray diffraction, conductivity and magnetic susceptibility measurements. In the copper and zinc complexes, a μ-hydroxo bridge links the two metal ions. In both cases, the coordination geometry is distorted octahedral. Magnetic and EPR data reveal weakly antiferromagnetic high spin Co(II) ions, compatible with a dinuclear structure. The magnetic characterization of the dinuclear Cu(II) compound indicates a ferromagnetically coupled dimer with weak antiferromagnetic intermolecular interactions. The intra-dimer ferromagnetic behaviour was unexpected for a Cu(II) dimer with such μ-hydroxo bridging topology. We discuss the influence on the magnetic properties of non-covalent interactions between the bridging moiety and the lattice free water molecules.

  16. Alkali-metalated forms of thiacalix[4]arenes.

    Zeller, Jürgen; Radius, Udo


    The alkali metal salts [TCALi4] (1), [TCANa4] (2), and [TCALK4] (3) of fully deprotonated p-tert-butyltetrathiacalix[4]arene (H(4)TCA) are readily available from the reactions of thiacalix[4]arene and n-BuLi, NaH, or KH as deprotonating reagents. Crystals of the sodium salts 2 and the potassium salt 3 suitable for X-ray diffraction were obtained in the form of the pyridine solvates [(TCA)2Na8.8py] (2.8py) and [(TCA)2K(8).8py] (3.8py). These molecules are dimers in the solid state but are structurally not related. In addition, the reaction of H(4)TCA and lithium hydroxide afforded the structurally characterized complex [(TCA)Li5(OH).4THF] (4). The molecular structure of 4 as well as the structures of 2.8py and 3.8py reveal a close relationship to the corresponding alkali metal salts of the calix[4]arenes.

  17. Synthesis, spectroscopic, DFT calculations and biological activity studies of ruthenium carbonyl complexes with 2-picolinic acid and a secondary ligand

    Shohayeb, Shahera M.; Mohamed, Rania G.; Moustafa, H.; El-Medani, Samir M.


    Thermal reaction of [Ru3(CO)12] with 2-picolinic acid (Hpic) in the absence and presence of a secondary ligand (pyridine, Py, bipyridine, Bipy, or thiourea, Tu) was investigated. Four complexes with molecular formulae: [Ru(CO)3(Hpic)], 1, [Ru2(CO)5(Hpic)(Py)], 2, [Ru2(CO)5(Hpic)(Tu)], 3 and [Ru2(CO)4(Hpic)(Bipy)], 4, were isolated. All complexes were characterized based on elemental analyses, IR, 1H NMR, magnetic studies, mass spectrometry and thermal analysis. The ligand and its complexes have been screened for antibacterial activities. Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligands. The optimized geometry parameters of the complexes were evaluated using B3LYP method and LANL2DZ basis set. The extent of natural charge population (core, valence and rydberg), exact electronic configuration, total Lewis and total non-Lewis are estimated and discussed in terms of natural bond orbitals (NBO) analysis.

  18. Metallo-porphyrazines with eight [5-thiopentyl 3,4,5-tris(benzyloxy)benzoate] groups: Synthesis, characterization, aggregation, and solubility behavior

    Gonca, Ergün


    Metal-free and metallo-porphyrazines having eight 5-hydroxypentylthio units at the peripheral positions have been prepared from 2,3-bis(5-hydroxypentylthio)maleonitrile. By the esterification reaction of magnesium hydroxy-porphyrazine with 3,4,5-tris(benzyloxy)benzoic acid in dicyclohexylcarbodiimide and toluene-p-sulfonic acid, the reactivity of the hydroxypentyl units was indicated. On the other hand, iron porphyrazine derivatives with eight [5-thiopentyl 3,4,5-tris(benzyloxy)benzoate] groups attached to the periphery positions were synthesized. By the reaction of metal-free porphyrazine with iron (II) acetate and further processing with HCl solution, FePzCl was obtained. Finally, by reacting FePzCl with pyridine or pyrazine, [FePz(py)2] and [FePz(pyz)]n complexes were prepared, respectively. The characterizations of target complexes were carried out by utilizing different spectroscopic methods such as FT-IR, UV-vis, mass, 1H NMR, and 13C NMR together with elemental analysis.

  19. One-dimensional Hydrogen-bonded Polymer Based on Tetra-iso-butyl-resorcin[4]arene and 2,6-Diacetylpyridine

    刘书群; 姚文锐; 张千峰


    The co-crystallization of tetra-iso-butyl-resorcin[4]arene 1 and 2,6-diacetyl- pyridine (Ac2py) from MeCN/CH2Cl2 yielded a multi-component complex 1(Ac2py(2H2O(0.5Me-CN 2, in which the upper rim of 1 is extended supramolecularly by way of hydrogen bonds. Complex 2 (C52H66.5N1.5O14) crystallizes in monoclinic, space group P21/m with a = 10.845(9), b = 20.805(17), c = 12.881(11) (A), β = 103.884(19)o, V = 2821(4) (A)3, Dc = 1.102 g/cm3 and Z = 2. The molecular structure shows that the two adjacent double-stranded arrays as well as linear and zigzag chains generated from Ac2py and water bridging to two resorcin[4] arene molecules, respectively, facilitate self-inclusion of one-dimensional hydrogen-bonded polymer.

  20. Synthesis and Structure of a Novel Ion-pair Palladium(Ⅱ) Compound Containing 2-Thioxo-1,3-dithiole-4,5-bis(thiolate)


    A novel ion-pair palladium(Ⅱ) compound, (NO2BzPy)2[Pd(dmit)2] (NO2BzPy+ = 1-(4-nitrobenzyl)pyridinium, dmit2- = 2-thioxo-1,3-dithiole-4,5-bis(thiolate)), was synthesized and characterized by single-crystal X-ray structure determination. This compound crystallizes in the monoclinic system, space group P21/n with a = 10.4463(11), b = 8.5627(9), c = 20.017(2) (A), β = 97.7730(10)°, V = 1774.1(3) (A)3, Z = 2, C30H22N4O4S10Pd, Mr = 929.52, Dc = 1.740 g/cm3, μ = 1.155 mm-1, S = 1.006, F(000) = 936, R = 0.0354 and wR = 0.0675. The most intriguing general structural feature of the compound is the completely segregated columnar stacks of anions and cations. There exist hydrogen-bonding interactions within the cation column.

  1. Infrared spectrum of the Ag(+)-(pyridine)2 ionic complex: probing interactions in artificial metal-mediated base pairing.

    Chakraborty, Shamik; Dopfer, Otto


    The isolated pyridine-Ag(+)-pyridine unit (Py-Ag(+)-Py) is employed as a model system to characterize the recently observed Ag(+)-mediated base pairing in DNA oligonucleotides at the molecular level. The structure and infrared (IR) spectrum of the Ag(+)-Py(2) cationic complex are investigated in the gas phase by IR multiple-photon dissociation (IRMPD) spectroscopy and quantum chemical calculations to determine the preferred metal-ion binding site and other salient properties of the potential-energy surface. The IRMPD spectrum has been obtained in the 840-1720 cm(-1) fingerprint region by coupling the IR free electron laser at the Centre Laser Infrarouge d'Orsay (CLIO) with a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer equipped with an electrospray ionization source. The spectroscopic results are interpreted with quantum chemical calculations conducted at the B3LYP/aug-cc-pVDZ level. The analysis of the IRMPD spectrum is consistent with a σ complex, in which the Ag(+) ion binds to the nitrogen lone pairs of the two Py ligands in a linear configuration. The binding motif of Py-Ag(+)-Py in the gas phase is the same as that observed in Ag(+)-mediated base pairing in solution. Ag(+) bonding to the π-electron system of the aromatic ring is predicted to be a substantially less-favorable binding motif.

  2. 1H, 13C, and 15N NMR Studies of Au(III and Pd(II Chloride Complexes and Organometallics with 2-Acetylpyridine and 2-Benzoylpyridine

    Daria Niedzielska


    Full Text Available Au(III and Pd(II chloride complexes with N(1,O-chelating 2-acetylpyridine (2apy and N(1- monodentately binding 2-benzoylpyridine (2bz′py-[Pd(2apyCl2], [Au(2bz′pyCl3], trans-[Pd(2bz′py2Cl2], as well as Au(III chloride organometallics with monoanionic forms of 2apy or 2bz′py, deprotonated at the acetyl or benzyl side groups (2apy*, 2bz′py*-[Au(2apy*Cl2], [Au(2bz′py*Cl2], were studied by 1H, 13C, and 15N NMR. 1H, 13C, and 15N coordination shifts (i.e., differences between the respective , , and chemical shifts of the same atom in the complex and ligand molecules: , , were discussed in relation to the molecular structures and coordination modes, as well as to the factors potentially influencing nuclear shielding. Analogous NMR measurements were performed for the new (2bz′pyH[AuCl4] salt.

  3. Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol.

    Brown, Margaret E; Mukhopadhyay, Aindrila; Keasling, Jay D


    We report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. In the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.

  4. Operation of a tokamak reactor in the radiative improved mode

    Morozov, D. Kh.; Mavrin, A. A.


    The operation of a nuclear fusion reactor has been simulated within a model based on experimental results obtained at the TEXTOR-94 tokamak and other facilities in which quasistationary regimes were achieved with long confinement times, high densities, and absence of the edge-localized mode. The radiative improved mode of confinement studied in detail at the TEXTOR-94 tokamak is the most interesting such regime. One of the most important problems of modern tokamaks is the problem of a very high thermal load on a divertor (or a limiter). This problem is quite easily solved in the radiative improved mode. Since a significant fraction of the thermal energy is reemitted by an impurity, the thermal loading is significantly reduced. As the energy confinement time τ E at high densities in the indicated mode is significantly larger than the time predicted by the scaling of ITERH-98P(y, 2), ignition can be achieved in a facility much smaller than the ITER facility at plasma temperatures below 20 keV. The revealed decrease in the degradation of the confinement time τ E with an increase in the introduced power has been analyzed.

  5. The reaction of [Fe(pic)3] with hydrogen peroxide: a UV-visible and EPR spectroscopic study (Hpic = picolinic acid).

    Jain, Sneh L; Bhattacharyya, Pravat


    The Gif family of catalysts, based on an iron salt and O2 or H2O2 in pyridine, allows the oxygenation of cyclic saturated hydrocarbons to ketones and alcohols under mild conditions. The reaction between [Fe(pic)3] and hydrogen peroxide in pyridine under GoAgg(III)(Fe(III)/Hpic catalyst) conditions was investigated by UV-visible spectrophotometry. Reactions were monitored at 430 and 520 nm over periods ranging from a few minutes to several hours at 20 degrees C. A number of kinetically stable intermediates were detected, and their relevance to the processes involved in the assembly of the active GoAgg(III) catalyst was determined by measuring the kinetics in the presence and absence of cyclohexane. EPR measurements at 110 K using hydrogen peroxide and t-BuOOH as oxidants were used to further probe these intermediates. Our results indicate that in wet pyridine [Fe(pic)3] undergoes reversible dissociation of one picolinate ligand, establishing an equilibrium with [Fe(pic)2(py)(OH)]. Addition of aqueous hydrogen peroxide rapidly generates the high-spin complex [Fe(pic)2(py)(eta1-OOH)] from the labilised hydroxy species. Subsequently the hydroperoxy species undergoes homolysis of the Fe-O bond, generating HOO. and [Fe(pic)2(py)2], the active oxygenation catalyst.

  6. Interaction of Lambda- and Delta-[Ru(bpy)2(pbmz)](PF6)2 with the oligonucleotide duplex d(CGCGAATTCGCG)2.

    Papakyriakou, Athanasios; Malandrinos, Gerasimos; Garoufis, Achilleas


    The interaction of the enantiomeric complexes Lambda- and Delta-[Ru(bpy)(2)(pbmz)](PF(6))(2) (bpy=2,2'-bipyridine, pbmz=2-(2'-pyridyl)benzimidazole) with the DNA duplex d(CGCGAATTCGCG)(2) was investigated by means of 2D NMR techniques. The synthesis of the enantiomers was based on the optically pure complexes Lambda- and Delta-[Ru(bpy)(2)(py)(2)](2+) and were characterized by CD and NMR spectroscopy. NMR data indicate that both enantiomers bind weakly to the oligonucleotide, approaching from the minor groove at the centre of the helix. The perturbation of the B-DNA conformation is minor with an apparent absence of enantioselectivity. Molecular modelling calculations in conjunction with the NOE data support the suggestion that more than one binding modes are present. The imidazole amine group of the pbmz ligand is probably hydrogen bonded to the DNA phosphodiesteric backbone at the AATT step, and this may provide an explanation for the diminished enantioselectivity observed.

  7. Agrometeorological models for groundnut crop yield forecasting in the Jaboticabal, São Paulo State region, Brazil

    Victor Brunini Moreto


    Full Text Available Forecast is the act of estimating a future event based on current data. Ten-day period (TDP meteorological data were used for modeling: mean air temperature, precipitation and water balance components (water deficit (DEF and surplus (EXC and soil water storage (SWS. Meteorological and yield data from 1990-2004 were used for calibration, and 2005-2010 were used for testing. First step was the selection of variables via correlation analysis to determine which TDP and climatic variables have more influence on the crop yield. The selected variables were used to construct models by multiple linear regression, using a stepwise backwards process. Among all analyzed models, the following was notable: Yield = - 4.964 x [SWS of 2° TDP of December of the previous year (OPY] – 1.123 x [SWS of 2° TDP of November OPY] + 0.949 x [EXC of 1° TDP of February of the productive year (PY] + 2.5 x [SWS of 2° TDP of February OPY] + 19.125 x [EXC of 1° TDP of May OPY] – 3.113 x [EXC of 3° TDP of January OPY] + 1.469 x [EXC of 3 TDP of January of PY] + 3920.526, with MAPE = 5.22%, R2 = 0.58 and RMSEs = 111.03 kg ha-1.

  8. Preparation of Co3O4 Nanostructures via a Hydrothermal- Assisted Thermal Treatment Method by Using of New Precursors

    Gholamrezaei, Sousan; Salavati-Niasari, Masoud; Hadadzadeh, Hassan; Behnamfar, Mohammad Taghi


    Co3O4 nanostructures have been synthesized via a hydrothermal-assisted thermal treatment process. A new complex formulated as [Co(py)2(H2O)2(NO3)2] was synthesized, and then used to prepare Co3O4 nanostructures. Cubic phase of spinel Co3O4 nanostructures with particle size of about 39 nm could be produced after calcination of the Co(OH)2 materials prepared with hydrothermal method at 160 °C for 15 h. Using of inorganic precursors decreased the time and temperature of Co3O4 preparation. The effect of pH on the morphology of the product s synthesized by hydrothermal reactions was investigated. It was found that the best morphology was achieved on pH=8, where was not prepared any precipitation. In this method, we could decrease the reaction temperature in synthetic rout to fabricate Co3O4 nanostructures. Nanostructures were characterized by SEM, TEM, X-ray diffraction (XRD), UV-visible, Fourier transformed infrared (FT-IR) spectroscopy and Nuclear magnetic resonance (1H-NMR).

  9. Synthesis and anticonvulsant activity of certain chalcone based pyrazoline compounds

    Sudhakara Rao Gerapati


    Full Text Available Convulsions are involuntary, violent, spasmodic and prolonged contractions of skeletal muscles. That means a patient may have epilepsy without convulsions and vice versa. Epilepsy is a common neurological abnormality affecting about 1% of the world population. The primary objectives of these synthesized compounds are to suppress seizures and provide neuroprotection by minimizing the effects from seizure attacks. Here some of the chalcones and chalcone based various pyrazolines were evaluated for anticonvulsant activity. Their structures have been elucidated on the basis of elemental analyses and spectroscopic studies (IR, 1H-NMR & Mass spectroscopy. A preliminary evaluation of the prepared compounds has indicated that some of them exhibit moderate to significant anticonvulsant activity compared to a diazepam standard1-3.  All compounds were tested for their anticonvulsant activity using maximal electroshock induced convulsions (MES in mice at a dose level of 4 mg/kg.b.w. The compounds  Ph1, Ph2 , Py2 ,Py3 and Py4 have shown  to  good anticonvulsant activity when doses are administered as 25mg/ kg.b.w  , reduced the phases of seizures severity and  found to be active and also  increased survival rate. Remaining compounds are less efficacious.

  10. A Novel Binuclear Cu(Ⅱ) Complex with Nitroxide Radicals Exhibiting Ferromagnetic Interactions

    刘尚远; 陈毅雯; 高东昭


    A new binuclear Cu(Ⅱ) complex with nitronyl nitroxide radicals [Cu(NIT3Py)2Cl2]2(NIT3Py = 2-(3'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in monoclinic,space group C2/c with a = 38.483(4),b = 7.2450(8),c = 27.559(3) ,β = 134.0180(10)°,V = 5525.6(10) 3,C48H64Cl4Cu2N12O8,Mr = 1206.00,Z = 4,Dc = 1.450 g/cm3,μ(MoKα) = 1.025 mm-1,F(000) = 2504,S = 1.066,the final R = 0.0471 and wR = 0.1121 for 3286 observed reflections(I 2σ(I)).The title complex consists of centrosymmetric dinuclear units [Cu(NIT3Py)2Cl2]2,in which the copper ions are square-pyramidally coordinated by two pyridyl nitrogen atoms of two radical ligands and three chlorine anions,two of which bridge the copper ions.The magnetic measurements show ferromagnetic interactions between the copper ions and the radical ligands.

  11. Combined analysis of chemical bonding in a Cu(II) dimer using QTAIM, Voronoi tessellation and Hirshfeld surface approaches.

    Vologzhanina, Anna V; Kats, Svitlana V; Penkova, Larisa V; Pavlenko, Vadim A; Efimov, Nikolay N; Minin, Vadim V; Eremenko, Igor L


    Interaction of 1-(1H-pyrazol-5-yl)ethanone oxime (H2PzOx) with copper(II) chloride in the presence of pyridine afforded a binuclear discrete [Cu2(HPzOx)2Cl2py2] complex, which was characterized by Fourier transform-IR and electron paramagnetic resonance (EPR) spectra, magnetochemistry and high-resolution X-ray diffraction experiments. Multipole refinement of X-ray diffraction data and density-functional theory (DFT) calculations of an isolated molecule allowed charge and spin distributions to be obtained for this compound. Magnetochemistry data, EPR spectra and DFT calculations of an isolated molecule show antiferromagnetic coupling between copper(II) ions. The spin distribution suggests an exchange pathway via the bridging pyrazole ring in the equatorial plane of the CuN4Cl coordination polyhedron, thus providing support for the classical superexchange mechanism; the calculated value of the magnetic coupling constant -2J is equal to 220 cm(-1), which compares well with the experimental value of 203 ± 2 cm(-1). Chemical connectivity was derived by Bader's 'quantum theory of atoms in molecules' and compared with Voronoi tessellation and Hirshfeld surface representations of crystal space. All methodologies gave a similar qualitative and semi-quantitative description of intra- and intermolecular connectivity.

  12. Effect of Fuelling Depth on the Fusion Performance and Particle Confinement of a Fusion Reactor

    Wang, Shijia; Wang, Shaojie


    The fusion performance and particle confinement of an international thermonuclear experimental reactor (ITER)-like fusion device have been modeled by numerically solving the energy transport equation and the particle transport equation. The effect of fuelling depth has been investigated. The plasma is primarily heated by the fusion produced alpha particles and the loss process of particles and energy in the scrape-off layer has been taken into account. To study the effect of fuelling depth on fusion performance, the ITERH-98P(y,2) scaling law has been used to evaluate the transport coefficients. It is shown that the particle confinement and fusion performance are significantly dependent on the fuelling depth. Deviation of 10% of the minor radius on fuelling depth can make the particle confinement change by ∼ 61% and the fusion performance change by ∼ 108%. The enhancement of fusion performance is due to the better particle confinement induced by deeper particle fuelling. supported by National Natural Science Foundation of China (Nos. 11175178 and 11375196) and the National Magnetic Confinement Fusion Science Program of China (No. 2014GB113000)

  13. Toward equatorial planarity about uranyl: synthesis and structure of tridentate nitrogen-donor {UO2}2+ complexes.

    Copping, Roy; Jeon, Byoungseon; Pemmaraju, C Das; Wang, Shuao; Teat, Simon J; Janousch, Markus; Tyliszczak, Tolek; Canning, Andrew; Grønbech-Jensen, Niels; Prendergast, David; Shuh, David K


    The reaction of UO2Cl2·3THF with the tridentate nitrogen donor ligand 2,6-bis(2-benzimidazolyl)pyridine (H2BBP) in pyridine leads to the formation of three different complexes: [(UO2)(H2BBP)Cl2] (1), [(UO)2(HBBP)(Py)Cl] (2), and [(UO2)(BBP)(Py)2] (3) after successive deprotonation of H2BBP with a strong base. Crystallographic determination of 1-3 reveals that increased charge through ligand deprotonation and displacement of chloride leads to equatorial planarity about uranyl as well as a more compact overall coordination geometry. Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectra of 1-3 at the U-4d edges have been recorded using a soft X-ray Scanning Transmission X-ray Microscope (STXM) and reveal the uranium 4d5/2 and 4d3/2 transitions at energies associated with uranium in the hexavalent oxidation state. First-principles Density Functional Theory (DFT) electronic structure calculations for the complexes have been performed to determine and validate the coordination characteristics, which correspond well to the experimental results.

  14. Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H2O)3

    GAO Dong-Zhao; WANG Shu-Ping; CHEN Jin; LI Li-Cun; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping


    A new Zn(II) nitronyl nitroxide complex [Zn(NIT4Py)(PDA)(H2O)3] (NIT4Py = 2-(4'-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2PDA = pyridine-2,5-dicarboxylic acid) has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.881(8), b = 7.356(4), c = 18.857(9)(A), β= 108.616(6)°, V = 2219.1(19)(A)3, C19H25N4O9Zn, Mr = 518.80, Dc = 1.553 g/cm3, μ(MoKα) = 1.165 mm-1, F(000) = 1076, Z = 4, the final R = 0.0269 and wR = 0.0715 for 3193 observed reflections with I > 2σ(I). The complex exists as discrete mononuclear molecules and the zinc(II) ion is six-coordinated with one radical ligand (NIT4Py), one bidentate pyridine-2,5-dicarboxylate anion and three water molecules. A three-dimensional network structure is formed through the intermolecular interactions.

  15. Study of reactivity of p-cymene ruthenium(II) dimer towards diphenyl-2-pyridylphosphine: Synthesis, characterization and molecular structures of [(6--cymene)RuCl2(PPh2Py)] and [(6--cymene)RuCl(PPh2Py)]BF4

    R Lalrempuia; Patrick J Carroll; Mohan Rao Kollipara


    The reaction of [{(6--cymene)Ru(-Cl)}2Cl2] with functionalized phosphine viz, diphenyl-2-pyridylphosphine yielded complexes of the type: (a) P-bonded complex [(6--cymene)RuCl2(PPh2Py)] (1), (b) P-, N-chelated complex [(6--cymene)RuCl-(PPh2Py)]BF4 (2) and [RuCl2(PPh2Py)2] (3) resulting from the displacement of the -cymene ligand. These complexes were characterized by 1H NMR, 31P NMR and analytical data. The structures of complexes 1 and 2 have been confirmed by single crystal X-ray diffraction study. Complex 1 crystallised in triclinic space group $\\bar{1}$ with = 10.9403 (3) Å, = 13.3108 (3) Å, = 10.5394 (10) Å, = 88.943 (2)°, = 117.193 (2)°, = 113.1680 (10)°, = 2 and = 1230.39 (5) Å3. The complex 2 crystallises in monoclinic space group 21 with = 9.1738 (4) Å, =14.0650 (6) s, = 10.7453 (5) Å, = 106.809 (1)°, = 2 and = 1327.22 (10) Å3.

  16. Evidence for single-chain magnet behavior in a Mn(III)-Ni(II) chain designed with high spin magnetic units: a route to high temperature metastable magnets.

    Clérac, Rodolphe; Miyasaka, Hitoshi; Yamashita, Masahiro; Coulon, Claude


    We herein present the synthesis, crystal structure, and magnetic properties of a new heterometallic chain of MnIII and NiII ions, [Mn2(saltmen)2Ni(pao)2(py)2](ClO4)2 (1) (saltmen2- = N,N'-(1,1,2,2-tetramethylethylene) bis(salicylideneiminate) and pao- = pyridine-2-aldoximate). The crystal structure of 1 was investigated by X-ray crystallographic analysis: compound 1 crystallized in monoclinic, space group C2/c (No. 15) with a = 21.140(3) A, b = 15.975(1) A, c = 18.6212(4) A, beta = 98.0586(4) degrees , V = 6226.5(7) A3, and Z = 4. This compound consists of two fragments, the out-of-plane dimer [Mn2(saltmen)2]2+ as a coordination acceptor building block and the neutral mononuclear unit [Ni(pao)2(py)2] as a coordination donor building block, forming an alternating chain having the repeating unit [-Mn-(O)2-Mn-ON-Ni-NO-]n. In the crystal structure, each chain is well separated with a minimum intermetallic distance between Mn and Ni ions of 10.39 A and with the absence of interchain pi overlaps between organic ligands. These features ensure a good magnetic isolation of the chains. The dc and ac magnetic measurements were performed on both the polycrystalline sample and the aligned single crystals of 1. Above 30 K, the magnetic susceptibility of this one-dimensional compound was successfully described in a mean field approximation as an assembly of trimers (Mn...Ni...Mn) with a NiII...MnIII antiferromagnetic interaction (J = -21 K) connected through a ferromagnetic MnIII...MnIII interaction (J'). However, the mean field theory fails to describe the magnetic behavior below 30 K emphasizing the one-dimensional magnetic character of the title compound. Between 5 and 15 K, the susceptibility in the chain direction was fitted to a one-dimensional Ising model leading to the same value of J'. Hysteresis loops are observed below 3.5 K, indicating a magnet-type behavior. In the same range of temperature, combined ac and dc measurements show a slow relaxation of the magnetization

  17. A Mononuclear Carboxylate-Rich Oxoiron(IV) Complex: a Structural and Functional Mimic of TauD Intermediate 'J'

    McDonald, Aidan R; Guo, Yisong; Vu, Van V; Bominaar, Emile L; Münck, Eckard; Que, Lawrence


    The pentadentate ligand (n)Bu-P2DA (2(b), (n)Bu-P2DA = N-(1',1'-bis(2-pyridyl)pentyl)iminodiacetate) was designed to bind an iron center in a carboxylate-rich environment similar to that found in the active sites of TauD and other α-ketoglutarate-dependent mononuclear non-heme iron enzymes. The iron(II) complex (n)Bu(4)N[Fe(II)(Cl)((n)Bu-P2DA)] (3(b)-Cl) was synthesized and crystallographically characterized to have a 2-pyridine-2-carboxylate donor set in the plane perpendicular to the Fe-Cl bond. Reaction of 3(b)-Cl with N-heterocyclic amines such as pyridine or imidazole yielded the N-heterocyclic amine adducts [Fe(II)(N)((n)Bu-P2DA)]. These adducts in turn reacted with oxo-transfer reagents at -95 °C to afford a short-lived oxoiron(IV) complex [Fe(IV)(O)((n)Bu-P2DA)] (5(b)) in yields as high as 90% depending on the heterocycle used. Complex 5(b) exhibits near-IR absorption features (λ(max) = 770 nm) and Mossbauer parameters (δ = 0.04 mm/s; ΔE(Q) = 1.13 mm/s; D = 27±2 cm(-1)) characteristic of an S = 1 oxoiron(IV) species. Direct evidence for an Fe=O bond of 1.66 Å was found from EXAFS analysis. DFT calculations on 5(b) in its S =1 spin state afforded a geometry-optimized structure consistent with the EXAFS data. They further demonstrated that the replacement of two pyridine donors in [Fe(IV)(O)(N4Py)](2+) (N4Py = N,N-(bis(2-pyridyl)methyl)N-bis(2-pyridylmethyl)amine) with carboxylate donors in 5(b) decreased the energy gap between the ground S = 1 and the excited S = 2 states, reflecting the weaker equatorial ligand field of 5(b) and accounting for its larger D value. Complex 5(b) reacted readily with dihydrotoluene, methyldiphenylphosphine and ferrocene at -60 °C, and in all cases was approximately a 5-fold more reactive oxidant than [Fe(IV)(O)(N4Py)](2+). The reactivity differences between these two complexes may arise from a combination of electronic and steric factors. Carboxylate-rich 5(b) represents the closest structural mimic reported thus far of

  18. Tuning through-bond Fe(III)/Fe(II) coupling by solvent manipulation of a central ruthenium redox couple.

    Lin, Yu-Chen; Chen, Wei-Tin; Tai, Joe; Su, Denny; Huang, Sheng-Yi; Lin, Ingrid; Lin, Ju-Ling; Lee, Mandy M; Chiou, Mong Feng; Liu, Yen-Hsiang; Kwan, Ken-Shin; Chen, Yuan-Jang; Chen, Hsing-Yin


    The relationships between the intervalence energy (E(IT)) and the free energy difference (DeltaG) that exists between the minima of redox isomers (Fe(II)-Ru(III)/Fe(III)-Ru(II)) for various heterobimetallic complexes [(R-Fcpy)Ru(NH(3))(5)](2+/3+) (R = H, ethyl, Br, actyl; Fcpy = (4-pyridyl)ferrocenyl; Ru(NH(3))(5) = pentaam(m)ineruthenium) were examined. The changes in DeltaG for the complexes in various solvents were due to the effects of both solvent donicity and the substituents. The intervalence energy versus DeltaG, DeltaG approximately FDeltaE(1/2) (DeltaE(1/2) = E(1/2)(Fe(III/II)) - E(1/2)(Ru(III/II))), plots for the complexes in various solvents suggest a nuclear reorganization energy (lambda) of approximately 6000 cm(-1) (Chen et al. Inorg. Chem. 2000, 39, 189). For [(R-Fcpy)Ru(NH(3))(5)](2+) and [(et-Fcpy)Ru(NH(3))(4)(py)](2+) (Ru(NH(3))(4) = trans-tetraam(m)ineruthenium; py = pyridine) in various solvents, the E(1/2)(Ru(III/II)) of rutheniumam(m)ine typically was less than the E(1/2)(Fe(III/II)) of the ferrocenyl moiety. However, the low-donicity solvents resulted in relatively large values of E(1/2)(Ru(III/II)) for [(et-Fcpy)Ru(NH(3))(4)(py)](2+/3+/4+). Under our unique solvent conditions, a dramatic end-to-end interaction was observed for the trimetal cation, [(et-Fcpy)(2)Ru(NH(3))(4)](4+), in which the [(et-Fcpy)(2)Ru(NH(3))(4)](4+) included a central trans-tetraam(m)ineruthenium(III) and a terminal Fe(II)/Fe(III) pair. In general, results of electrochemical studies of [(et-Fcpy)(2)Ru(NH(3))(4)](2+) indicated both solvent-tunable E(1/2)(Ru(III/II)) (1 e(-)) and solvent-insensitive E(1/2)(Fe(III/II)) (2 e(-)) redox centers. However, in nitriles, two E(1/2)(Fe(III/II)) peaks were found with DeltaE(1/2)(Fe(III/II) - Fe(III/II)) ranging between 83 and 108 mV at a terminal metal-to-metal distance of up to 15.6 A. Furthermore, the bridging dpi orbital of the ruthenium center mediated efficient end-to-end interaction between the combinations of the terminal

  19. Synthesis and Crystal Structures of a 1D Cu Coordination Polymer Based on Tetrakis[3-(carboxyphenyl)oxamethyl]methane Acid%1,1,1,1-(间羟基苯甲酸-氧甲基)甲烷构筑的一维链状铜配合物的合成与晶体结构

    曹成; 魏太保; 张勤生; 鲁彦云; 张有明


    A semi-rigid tetrahedral linker tetrakis [3-(carboxyphenyl)oxamethyl]methane acid (H4L) and its coordination polymer [Cu(H2L)(Py)2]n (Py=pyridyne) were synthesized and characterized by elemental analyses, IR spectroscopy, etc. The single crystal structure show the title complex crystallizes in the monoclinic system with space group C2/c, a= 1.943 0(7) nm, 6=0.926 4(3) ran, c=2.784 9(9) nm, β=96.763(3)°, V =4.978(3) nm3, Z=4, F(000)=l 724. In the complex each Cu(II) atoms is coordinated with two pyridyne and two oxygen atom from two arms of H2L2-, and displays a one-dimensional line topology with the other two arms free. Platon calculation show that the guest accessible volume (1.397 nm3 per unit cell) comprises 28.1% of the unit cell volume. The thermal analysis shows the title compound is trable up to 236.9 ℃. CCDC: 817405.%设计合成了半刚性四足配体H4L(H4L=1,1,1,1-(间羟基苯甲酸-氧甲基)甲烷),在溶剂热条件下合成了其Cu(Ⅱ)配位聚合物[Cu(H2L)(Py)2]n(Py=吡啶),并进行了常规表征,用单晶X射线衍射测定了配合物的晶体结构.结果表明此配合物属单斜晶系,C2/c空间群,a=1.9430(7) nm,b=0.9264(3) nm,c=2.7849(9) nm,β=96.763(3)°,V=4.978(3) nm3,Z=4,F(000)=1724.配合物中的金属铜离子与2个相邻1,1,1,1-(间羟基苯甲酸-羟甲基)甲烷上的羧基及2个吡啶四配位而堆积成一维链状配位聚合物,配体中另外两臂未参与有效配位.Platon计算表明每个晶胞的溶剂可及体积约为1.397 nm3(扣除表面原子的范德华半径),占晶胞体积的28.1%,TGA分析表明该框架在236.9℃前保持稳定.

  20. Novel metal-organic and supramolecular 3D frameworks constructed from flexible biphenyl-2,5,3‧-tricarboxylate blocks: Synthesis, structural features and properties

    You, Ao; Li, Yu; Zhang, Ze-Min; Zou, Xun-Zhong; Gu, Jin-Zhong; Kirillov, Alexander M.; Chen, Jin-Wei; Chen, Yun-Bo


    Biphenyl-2,5,3‧-tricarboxylic acid (H3L) was selected as an unexplored tricarboxylate building block and applied for the hydrothermal synthesis of three novel coordination compounds, namely a 0D tetramer [Co4(HL)2(μ3-HL)2(phen)6(H2O)2]·3H2O (1) and two 3D metal-organic frameworks (MOFs) [Cd3(μ5-L)(μ6-L)(py)(μ-H2O)2(H2O)]n·H2O (2) and [Zn3(μ4-L)2(2,2‧-bpy)(μ-4,4‧-bpy)]n·2H2O (3). These products were easily generated in aqueous medium from the corresponding metal(II) chlorides, H3L, and various N-donor ancillary ligands, selected from 1,10-phenanthroline (phen), pyridine (py), 2,2‧-bipyridine (2,2‧-bpy), and 4,4‧-bipyridine (4,4‧-bpy). Compounds 1-3 were isolated as stable crystalline solids and were fully characterized by IR and UV-vis spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a discrete tetracobalt(II) structure, which is extended into a 3D H-bonded network with the pcu topology. In contrast, MOF 2 discloses a very complex trinodal 4,5,12-connected net with an undocumented topology, while MOF 3 features the nce/I topological framework. The magnetic (for 1) and luminescence (for 2 and 3) properties were also studied and discussed. The present study thus widens a still very limited family of metal-organic and supramolecular frameworks driven by flexible biphenyl-2,5,3‧-tricarboxylate building blocks.

  1. Gold complexes with the selenolate ligand [2-(Me2NCH2)C6H4Se]-.

    Crespo, Olga; Gimeno, M Concepción; Laguna, Antonio; Kulcsar, Monika; Silvestru, Cristian


    The reaction of [2-(Me(2)NCH(2))C(6)H(4)Se]M (M = Li, K) with the gold(phosphine) complexes [AuCl(PR(3))] gives the mononuclear gold-selenolate species [Au{SeC(6)H(4)(CH(2)NMe(2))-2}(PPh(3))] (1) or [Au{SeC(6)H(4)(CH(2)NMe(2))-2}(PPh(2)py)] (2), respectively. The treatment of the [2-(Me(2)NCH(2))C(6)H(4)Se]M with [Au(2)Cl(2)(mu-P-P)] [P-P = bis(diphenylphosphino)methane (dppm), bis(diphenylphosphino)ethane (dppe), 1,1'-bis(diphenylphosphino)ferrocene (dppf)] derivatives gives complexes with stoichiometry [Au(2){SeC(6)H(4)(CH(2)NMe(2))-2}(2)(mu-P-P)] [P-P = dppm (3), dppe (4), or dppf (5)]. These complexes exhibit a different structural framework, that is, 4 crystallizes as a chain polymer with intermolecular aurophilic bonding, while 5 shows an intramolecular Au(I)...Au(I) interaction. The gold(III) derivative Bu(4)N[Au(C(6)F(5))(3){SeC(6)H(4)(CH(2)NMe(2))-2}] (6) is obtained by reaction of [2-(Me(2)NCH(2))C(6)H(4)Se]K and Bu(4)N[AuBr(C(6)F(5))(3)], in a 1:1 molar ratio. These species exhibit luminescence which probably arises from a mixed (3)LMMCT and (3)MC excited state. The emission properties in these complexes seem to be useful for structural predictions and lead to the proposal of intermolecular aggregation in the solid state and frozen solution for complexes 1, 2, 3, whose crystal structures have not been elucidated.

  2. Synthesis of electromagnetic functionalized nickel/polypyrrole core/shell composites.

    Xu, Ping; Han, Xijiang; Wang, Chao; Zhou, Donghua; Lv, Zushun; Wen, Aihua; Wang, Xiaohong; Zhang, Bin


    Microstructured Ni/PPy (PPy: polypyrrole) core/shell composites were prepared from an in situ chemical oxidative polymerization of pyrrole (Py) monomer in the presence of Ni powder, with ammonium persulfate (APS) as oxidant and citric acid (C6H8O7) as dopant. X-ray diffraction and Fourier transform infrared analyses indicate that there is no chemical interaction between Ni powder and protonated PPy. The mass percentages of PPy, calculated from the remanent weight percentages of Ni/PPy composites after thermogravimetric analysis, are in consistent with those as designed. The prepared Ni/PPy composites are soft and ferromagnetic materials, where a linear increase of saturation magnetization (MS) and remanent magnetization (MR) as a function of Ni powder content is proposed. The permeability of Ni/PPy composites presents a natural magnetic resonance at 6.0 GHz, and Cole-Cole semicircle was applied to explain the permittivity. Electromagnetic absorption less than -10 dB is found for Ni/Py=4:1 (11-15.4 GHz) and Ni/Py=2:1 (12-17.5 GHz). The ternary Debye relaxations for enhanced dielectric loss induced by PPy coatings and proper electromagnetic impedance matching due to the synergetic consequence of the Ni cores and PPy shells contribute to the improvement of the electromagnetic absorption of the Ni/PPy core/shell composites. It is important to notice that dielectric loss and electrical conductivity should be considered simultaneously in designing dielectric-type electromagnetic absorbing materials.

  3. The complete genomic sequence of pepper yellow leaf curl virus (PYLCV and its implications for our understanding of evolution dynamics in the genus polerovirus.

    Aviv Dombrovsky

    Full Text Available We determined the complete sequence and organization of the genome of a putative member of the genus Polerovirus tentatively named Pepper yellow leaf curl virus (PYLCV. PYLCV has a wider host range than Tobacco vein-distorting virus (TVDV and has a close serological relationship with Cucurbit aphid-borne yellows virus (CABYV (both poleroviruses. The extracted viral RNA was subjected to SOLiD next-generation sequence analysis and used as a template for reverse transcription synthesis, which was followed by PCR amplification. The ssRNA genome of PYLCV includes 6,028 nucleotides encoding six open reading frames (ORFs, which is typical of the genus Polerovirus. Comparisons of the deduced amino acid sequences of the PYLCV ORFs 2-4 and ORF5, indicate that there are high levels of similarity between these sequences to ORFs 2-4 of TVDV (84-93% and to ORF5 of CABYV (87%. Both PYLCV and Pepper vein yellowing virus (PeVYV contain sequences that point to a common ancestral polerovirus. The recombination breakpoint which is located at CABYV ORF3, which encodes the viral coat protein (CP, may explain the CABYV-like sequences found in the genomes of the pepper infecting viruses PYLCV and PeVYV. Two additional regions unique to PYLCV (PY1 and PY2 were identified between nucleotides 4,962 and 5,061 (ORF 5 and between positions 5,866 and 6,028 in the 3' NCR. Sequence analysis of the pepper-infecting PeVYV revealed three unique regions (Pe1-Pe3 with no similarity to other members of the genus Polerovirus. Genomic analyses of PYLCV and PeVYV suggest that the speciation of these viruses occurred through putative recombination event(s between poleroviruses co-infecting a common host(s, resulting in the emergence of PYLCV, a novel pathogen with a wider host range.

  4. Effect of phenyl and benzyl group in heterocyclic dithiocarbamates on the ZnS 4N chromophore: Synthesis, spectral, valence-bond parameters and single crystal X-ray structural studies on (pyridine)bis(1,2,3,4-tetrahydroquinolinedithiocarbamato)zinc(II) and (pyridine)bis(1,2,3,4-tetrahydroisoquinolinedithiocarbamato)zinc(II)

    Srinivasan, N.; Thirumaran, S.; Ciattini, Samuele


    Two Zn(II)dithiocarbamates with ZnS 4N chromophores have been synthesized ([Zn(thqdtc) 2(py)] ( 1) and [Zn(thiqdtc) 2(py)] ( 2) (where thqdtc = 1,2,3,4-tetrahydroquinolinedithiocarbamate, thiqtc = 1,2,3,4-tetrahydroisoquinolinedithiocarbamate and py = pyridine)) from [Zn(thqdtc) 2] ( 3) and [Zn(thiqdtc) 2] ( 4), respectively. Their structures and properties have been characterized by IR and NMR spectra. The structures of both the complexes were determined by single crystal X-ray crystallography. The observed deshielding of the H-2 protons for 1 and 3 and H-1 and H-3 protons for 2 and 4 in the 1H NMR spectra is attributed to the drift of electrons from the nitrogen of the NR 2 group, forcing a high electron density towards sulfur via the thioureide π-system. In the 13C NMR spectra, the most important thioureide (N 13CS 2) carbon signals are observed in the region 204-207 ppm. The upfield shift of NCS 2 carbon signal for 1 (204.2 ppm) from the chemical shift value of 2 (206.9 ppm) is due to electron withdrawing resonance effect of phenyl ring thereby decreasing the double bond character in tetrahydroquinolinedithiocarbamate, whereas benzyl group in tetrahydroisoquinolinedithiocarbamate cannot participate in resonance delocalization in the same way. Single crystal X-ray structural analysis of 1 and 2 showed that the zinc atom is pentacoordinated with four sulfur atoms from the dithiocarbamate ligands and one nitrogen atom from the pyridine. VBS values support the correctness of the determined structure. The lower VBS value of 2 is due to the steric effect exerted by the thiqdtc. The phenyl and benzyl group in the heterocyclic dithiocarbamates influences the electronic properties of 1 and 2. The shift of ν C- N(thioureide) and thioureide N 13CS 2 carbon signals are correlated with the electronic effects of the dithiocarbamate ligands.

  5. Synthesis, structure, and reactivity of rhodium and iridium complexes of the chelating bis-sulfoxide tBuSOC2H4SOtBu. Selective O-H activation of 2-hydroxy-isopropyl-pyridine.

    Schaub, Thomas; Diskin-Posner, Yael; Radius, Udo; Milstein, David


    The chloro-bridged rhodium and iridium complexes [M2(BTSE)2Cl2] (M = Rh 1, Ir 2) bearing the chelating bis-sulfoxide tBuSOC2H4SOtBu (BTSE) were prepared by the reaction of [M2(COE)4Cl2] (M = Rh, Ir; COE = cyclooctene) with an excess of a racemic mixture of the ligand. The cationic compounds [M(BTSE)2][PF6] (M = Rh 3, Ir 4), bearing one S- and one O-bonded sulfoxide, were also obtained in good yields. The chloro-bridges in 2 can be cleaved with 2-methyl-6-pyridinemethanol and 2-aminomethyl pyridine, resulting in the iridium(I) complexes [Ir(BTSE)(Py)(Cl)] (Py = 2-methyl-6-pyridinemethanol 5, 2-aminomethyl-pyridine 6). In case of the bulky 2-hydroxy- isopropyl-pyridine, selective OH oxidative addition took place, forming the Ir(III)-hydride [Ir(BTSE)(2-isopropoxy-pyridine)(H)(Cl)] 7, with no competition from the six properly oriented C-H bonds. The cationic rhodium(I) and iridium(I) compounds [M(BTSE)(2-aminomethyl-pyridine)][X] (M = Rh 8, Ir 10), [Rh(BTSE)(2-hydroxy- isopropyl-pyridine)][X] 9(stabilized by intramolecular hydrogen bonding), [Ir(BTSE)(pyridine)2][PF6] 12, [Ir(BTSE)(alpha-picoline)2][PF6] 13, and [Rh(BTSE)(1,10-phenanthroline)][PF6] 14 were prepared either by chloride abstraction from the dimeric precursors or by replacement of the labile oxygen bonded sulfoxide in 3 or 4. Complex 14 exhibits a dimeric structure in the solid state by pi-pi stacking of the phenanthroline ligands.

  6. Iron coordination chemistry with new ligands containing triazole and pyridine moieties. Comparison of the coordination ability of the N-donors.

    Ségaud, Nathalie; Rebilly, Jean-Noël; Sénéchal-David, Katell; Guillot, Régis; Billon, Laurianne; Baltaze, Jean-Pierre; Farjon, Jonathan; Reinaud, Olivia; Banse, Frédéric


    We report the synthesis, characterization, and solution chemistry of a series of new Fe(II) complexes based on the tetradentate ligand N-methyl-N,N'-bis(2-pyridyl-methyl)-1,2-diaminoethane or the pentadentate ones N,N',N'-tris(2-pyridyl-methyl)-1,2-diaminoethane and N,N',N'-tris(2-pyridyl-methyl)-1,3-diaminopropane, modified by propynyl or methoxyphenyltriazolyl groups on the amino functions. Six of these complexes are characterized by X-ray crystallography. In particular, two of them exhibit an hexadentate coordination environment around Fe(II) with two amino, three pyridyl, and one triazolyl groups. UV-visible and cyclic voltammetry experiments of acetonitrile solutions of the complexes allow to deduce accurately the structure of all Fe(II) species in equilibrium. The stability of the complexes could be ranked as follows: [L(5)Fe(II)-py](2+) > [L(5)Fe(II)-Cl](+) > [L(5)Fe(II)-triazolyl](2+) > [L(5)Fe(II)-(NCMe)](2+), where L(5) designates a pentadentate coordination sphere composed of the two amines of ethanediamine and three pyridines. For complexes based on propanediamine, the hierarchy determined is [L(5)Fe(II)-Cl](+) > [L(5)Fe(II)(OTf)](+) > [L(5)Fe(II)-(NCMe)](2+), and no ligand exchange could be evidenced for [L(5)Fe(II)-triazolyl](2+). Reactivity of the [L(5)Fe(II)-triazolyl](2+) complexes with hydrogen peroxide and PhIO is similar to the one of the parent complexes that lack this peculiar group, that is, generation of Fe(III)(OOH) and Fe(IV)(O), respectively. Accordingly, the ability of these complexes at catalyzing the oxidation of small organic molecules by these oxidants follows the tendencies of their previously reported counterparts. Noteworthy is the remarkable cyclooctene epoxidation activity by these complexes in the presence of PhIO.

  7. Rational Synthesis and Investigation of Porous Metal-Organic Framework Materials from a Preorganized Heterometallic Carboxylate Building Block.

    Sapianik, Aleksandr A; Zorina-Tikhonova, Ekaterina N; Kiskin, Mikhail A; Samsonenko, Denis G; Kovalenko, Konstantin A; Sidorov, Alexey A; Eremenko, Igor L; Dybtsev, Danil N; Blake, Alexander J; Argent, Stephen P; Schröder, Martin; Fedin, Vladimir P


    The tetranuclear heterometallic complex [Li2Zn2(piv)6(py)2] (1, where piv(-) = pivalate and py = pyridine) has been successfully employed as a presynthesized node for the construction of four porous metal-organic frameworks (MOFs) [Li2Zn2(R-bdc)3(bpy)]·solv (2-R, R-bdc(2-); R = H, Br, NH2, NO2) by reaction with 4,4'-bipyridine (bpy) and terephthalate anionic linkers. The [Li2Zn2] node is retained in the products, representing a rare example of the rational step-by-step design of isoreticular MOFs based on complex heterometallic building units. The permanent porosity of the activated frameworks was confirmed by gas adsorption isotherm measurements (N2, CO2, CH4). Three compounds, 2-H, 2-Br, and 2-NH2 (but not 2-NO2), feature extensive hysteresis between the adsorption and desorption curves in the N2 isotherms at low pressures. The substituents R decorate the inner surface and also control the aperture of the channels, the volume of the micropores, and the overall surface area, thus affecting both the gas uptake and adsorption selectivity. The highest CO2 absorption at ambient conditions (105 cm(3)·g(-1) or 21 wt % at 273 K and 1 bar for 2-NO2) is above the average values for microporous MOFs. The photoluminescent properties of the prototypic 2-H as well as the corresponding host-guest compounds with various aromatic molecules (benzene, toluene, anisole, and nitrobenzene) were systematically investigated. We discovered a rather complex pattern in the emission response of this material depending on the wavelength of excitation as well as the nature of the guest molecules. On the basis of the crystal structure of 2-H, a mechanism for these luminescent properties is proposed and discussed.

  8. Strategies for the hyperpolarization of acetonitrile and related ligands by SABRE.

    Mewis, Ryan E; Green, Richard A; Cockett, Martin C R; Cowley, Michael J; Duckett, Simon B; Green, Gary G R; John, Richard O; Rayner, Peter J; Williamson, David C


    We report on a strategy for using SABRE (signal amplification by reversible exchange) for polarizing (1)H and (13)C nuclei of weakly interacting ligands which possess biologically relevant and nonaromatic motifs. We first demonstrate this via the polarization of acetonitrile, using Ir(IMes)(COD)Cl as the catalyst precursor, and confirm that the route to hyperpolarization transfer is via the J-coupling network. We extend this work to the polarization of propionitrile, benzylnitrile, benzonitrile, and trans-3-hexenedinitrile in order to assess its generality. In the (1)H NMR spectrum, the signal for acetonitrile is enhanced 8-fold over its thermal counterpart when [Ir(H)2(IMes)(MeCN)3](+) is the catalyst. Upon addition of pyridine or pyridine-d5, the active catalyst changes to [Ir(H)2(IMes)(py)2(MeCN)](+) and the resulting acetonitrile (1)H signal enhancement increases to 20- and 60-fold, respectively. In (13)C NMR studies, polarization transfers optimally to the quaternary (13)C nucleus of MeCN while the methyl (13)C is hardly polarized. Transfer to (13)C is shown to occur first via the (1)H-(1)H coupling between the hydrides and the methyl protons and then via either the (2)J or (1)J couplings to the respective (13)Cs, of which the (2)J route is more efficient. These experimental results are rationalized through a theoretical treatment which shows excellent agreement with experiment. In the case of MeCN, longitudinal two-spin orders between pairs of (1)H nuclei in the three-spin methyl group are created. Two-spin order states, between the (1)H and (13)C nuclei, are also created, and their existence is confirmed for Me(13)CN in both the (1)H and (13)C NMR spectra using the Only Parahydrogen Spectroscopy protocol.

  9. Synthesis, spectroscopy (IR, multinuclear NMR, ESI-MS), diffraction, density functional study and in vitro antiproliferative activity of pyrazole-beta-diketone dihalotin(IV) compounds on 5 melanoma cell lines.

    Pettinari, Claudio; Caruso, Francesco; Zaffaroni, Nadia; Villa, Raffaella; Marchetti, Fabio; Pettinari, Riccardo; Phillips, Christine; Tanski, Joseph; Rossi, Miriam


    Novel 4-acylpyrazolon-5-ato-dihalotin(IV) complexes, [Q2SnX2], (X = F, Cl, Br or I); HQ = HQ(CHPh2) (1,2-dihydro-3-methyl-1-phenyl-4-(2,2-diphenylacetyl)pyrazol-5-one), HQ(Bn) (1,2-dihydro-3-methyl-1-phenyl-4-(2-phenylacetyl)pyrazol-5-one) or HQ(CF3,py) (4-(2,2,2-trifluoroacetyl)-1,2-dihydro-3-methyl-1-(pyridin-2-yl)pyrazol-5-one) have been synthesized and characterized by spectroscopic (IR, 1H, 13C, 19F and 119Sn NMR, electrospray ionisation mass spectrometry (ESI-MS)), analytical and structural methods (X-ray and density functional theory). 119Sn chemical shifts depend on the nature of the halides bonded to tin. Isomer conversion, detected in solution by NMR spectroscopy, is related to the acyl moiety bulkiness while the cis(Cl)-cis(acyl)-trans(pyrazolonato) scheme is found in the solid state. The in vitro antiproliferative tests of three derivatives on three human melanoma cell lines (JR8, SK-MEL-5, MEL501) and two melanoma cell clones (2/21 and 2/60) show dose-dependent decrease of cell proliferation in all cell lines. The activity correlates with the nature of the substituent on position 1 of pyrazole, decreasing in the order pyridyl>Ph>methyl. The activity for (Q(CF3,py))2SnCl2 on the SK-MEL-5 cell line is IC50 = 50 microM.

  10. Electrochemical, spectroscopic and theoretical studies of a simple bifunctional cobalt corrole catalyst for oxygen evolution and hydrogen production.

    Lei, Haitao; Han, Ali; Li, Fengwang; Zhang, Meining; Han, Yongzhen; Du, Pingwu; Lai, Wenzhen; Cao, Rui


    Six cobalt and manganese corrole complexes were synthesized and examined as single-site catalysts for water splitting. The simple cobalt corrole [Co(tpfc)(py)2] (1, tpfc = 5,10,15-tris(pentafluorophenyl)corrole, py = pyridine) catalyzed both water oxidation and proton reduction efficiently. By coating complex 1 onto indium tin oxide (ITO) electrodes, the turnover frequency for electrocatalytic water oxidation was 0.20 s(−1) at 1.4 V (vs. Ag/AgCl, pH = 7), and it was 1010 s(−1) for proton reduction at −1.0 V (vs. Ag/AgCl, pH = 0.5). The stability of 1 for catalytic oxygen evolution and hydrogen production was evaluated by electrochemical, UV-vis and mass measurements, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), which confirmed that 1 was the real molecular catalyst. Titration and UV-vis experiments showed that the pyridine group on Co dissociated at the beginning of catalysis, which was critical to subsequent activation of water. A proton-coupled electron transfer process was involved based on the pH dependence of the water oxidation reaction catalyzed by 1. As for manganese corroles 2–6, although their oxidizing powers were comparable to that of 1, they were not as stable as 1 and underwent decomposition at the electrode. Density functional theory (DFT) calculations indicated that water oxidation by 1 was feasible through a proposed catalytic cycle. The formation of an O–O bond was suggested to be the rate-determining step, and the calculated activation barrier of 18.1 kcal mol(−1) was in good agreement with that obtained from experiments.

  11. Synthesis and crossover reaction of TEMPO containing block copolymer via ROMP

    Olubummo Adekunle


    Full Text Available We report on the block copolymerization of two structurally different norbornene monomers (±-endo,exo-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid dimethylester (7, and (±-endo,exo-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid bis(1-oxyl-2,2,6,6-tetramethyl-piperidin-4-yl ester (9 using ruthenium based Grubbs’ type initiators [(PCy32Cl2Ru(benzylidene] G1 (PCy3 = tricyclohexylphosphine, [(H2IMes(PCy3Cl2Ru(benzylidene] G2 (H2IMes = 1,3-bis(mesityl-2-imidazolidinylidene, [(H2IMes(py2Cl2Ru(benzylidene] G3 (py = pyridine or 3-bromopyridine and Umicore type initiators [(PCy32Cl2Ru(3-phenylinden-1-ylidene] U1 (PCy3 = tricyclohexylphosphine, [(H2IMes(PCy3Cl2Ru(3-phenylinden-1-ylidene] U2 (H2IMes = 1,3-bis(mesityl-2-imidazolidinylidene, [(H2IMes(pyCl2Ru(3-phenylinden-1-ylidene] U3 (py = pyridine or 3-bromopyridine via ring opening polymerization (ROMP. The crossover reaction and the polymerization kinetics were investigated using matrix assisted laser desorption ionization mass spectroscopy (MALDI-TOF and nuclear magnetic resonance (NMR, respectively. MALDI showed that there was a complete crossover reaction after the addition of 25 equivalents of the second monomer. NMR investigation showed that U3 gave a faster rate of polymerization in comparison to U1. The synthesis of block copolymers with molecular weights up to Mn = 31 000 g/mol with low polydispersities (Mw/Mn = 1.2 is reported.

  12. Synthesis, spectroscopic characterization, and determination of the solution association energy of the dimer [Co{N(SiMe3)2}2]2: magnetic studies of low-coordinate Co(II) silylamides [Co{N(SiMe3)2}2L] (L = PMe3, pyridine, and THF) and related species that reveal evidence of very large zero-field splittings.

    Bryan, Aimee M; Long, Gary J; Grandjean, Fernande; Power, Philip P


    The synthesis, magnetic, and spectroscopic characteristics of the synthetically useful dimeric cobalt(II) silylamide complex [Co{N(SiMe3)2}2]2 (1) and several of its Lewis base complexes have been investigated. Variable-temperature nuclear magnetic resonance (NMR) spectroscopy of 1 showed that it exists in a monomer-dimer equilibrium in benzene solution and has an association energy (ΔGreacn) of -0.30(20) kcal mol(-1) at 300 K. Magnetic data for the polycrystalline, red-brown [Co{N(SiMe3)2}2]2 (1) showed that it displays strong antiferromagnetic exchange coupling, expressed as -2JexS1S2, between the two S = (3)/2 cobalt(II) centers with a Jex value of -215(5) cm(-1), which is consistent with its bridged dimeric structure in the solid state. The electronic spectrum of 1 in solution is reported for the first time, and it is shown that earlier reports of the melting point, synthesis, electronic spectrum, and magnetic studies of the monomer "Co{N(SiMe3)2}2" are consistent with those of the bright green-colored tetrahydrofuran (THF) complex [Co{N(SiMe3)2}2(THF)] (4). Treatment of 1 with various Lewis bases yielded monomeric three-coordinated species-[Co{N(SiMe3)2}2(PMe3)] (2), and [Co{N(SiMe3)2}2(THF)] (4), as well as the previously reported [Co{N(SiMe3)2}2(py)] (3)-and the four-coordinated species [Co{N(SiMe3)2}2(py)2] (5) in good yields. The paramagnetic complexes 2-4 were characterized by electronic and (1)H NMR spectroscopy, and by X-ray crystallography in the case of 2 and 4. Magnetic studies of 2-5 and of the known three-coordinated cobalt(II) species [Na(12-crown-4)2][Co{N(SiMe3)2}3] (6) showed that they have considerably larger χMT products and, hence, magnetic moments, than the spin-only values of 1.875 emu K mol(-1) and 3.87 μB, which is indicative of a significant zero-field splitting and g-tensor anisotropy resulting from the pseudo-trigonal crystal field. A fit of χMT for 2-6 yields a large g-tensor anisotropy, large negative D-values (between -62 cm(-1

  13. Oligo-nuclear silver thiocyanate complexes with monodentate tertiary phosphine ligands, including novel 'cubane' and 'step' tetramer forms of AgSCN : PR3 (1:1)4.

    Bowmaker, Graham A; Di Nicola, Corrado; Effendy; Hanna, John V; Healy, Peter C; King, Scott P; Marchetti, Fabio; Pettinari, Claudio; Robinson, Ward T; Skelton, Brian W; Sobolev, Alexandre N; Tăbăcaru, Aurel; White, Allan H


    Adducts of a number of tertiary pnicogen ligands ER(3) (triphenyl-phosphine and -arsine (PPh(3),AsPh(3)), diphenyl,2-pyridylphosphine (PPh(2)py), tris(4-fluorophenyl)phosphine (P(C(6)H(4)-4F)(3)), tris(2-tolyl)phosphine (P(o-tol)(3)), tris(cyclohexyl)phosphine (PCy(3))), with silver(I) thiocyanate, AgSCN are structurally and spectroscopically characterized. The 1:3 AgSCN : ER(3) complexes structurally defined (for PPh(3),AsPh(3) (diversely solvated)) take the form [(R(3)E)(3)AgX], the thiocyanate X = NCS being N-bound, thus [(Ph(3)E)Ag(NCS)]. A 1:2 complex with PPh(2)py, takes the binuclear form [(pyPh(2)P)(2)Ag()Ag(PPh(2)py)(2)] with an eight-membered cyclic core. 1:1 complexes are defined with PPh(2)py, P(o-tol)(3) and PCy(3); binuclear forms [(R(3)P)Ag()Ag(PR(3))] are obtained with P(o-tol)(3) (two polymorphs), while novel isomeric tetranuclear forms, which may be envisaged as dimers of dimers, are obtained with PPh(2)py, and, as further polymorphs, with PCy(3); these latter may be considered as extensions of the 'cubane' and 'step' forms previously described for [(R(3)E)AgX](4) (X = halide) complexes. Solvent-assisted mechanochemical or solvent-assisted solid-state synthesis methods were employed in some cases, where complexes could not be obtained by conventional solution methods, or where such methods yielded a mixture of polymorphs unsuitable for solid-state spectroscopy. The wavenumbers of the ν(CN) bands in the IR spectra are in broad agreement with the empirical rule that distinguishes bridging from terminal bonding, but exceptions occur for compounds that have a double SCN bridged dimeric structure, and replacement of PPh(3) with PPh(2)py apparently causes a significant decrease in ν(CN) to well below the range expected for bridging SCN in these structures. (31)P CP MAS NMR spectra yield additional parameters that allow a correlation between the structures and spectra.

  14. Two Polymorphic Forms of a Six-Coordinate Mononuclear Cobalt(II) Complex with Easy-Plane Anisotropy: Structural Features, Theoretical Calculations, and Field-Induced Slow Relaxation of the Magnetization.

    Roy, Subhadip; Oyarzabal, Itziar; Vallejo, Julia; Cano, Joan; Colacio, Enrique; Bauza, Antonio; Frontera, Antonio; Kirillov, Alexander M; Drew, Michael G B; Das, Subrata


    A mononuclear cobalt(II) complex [Co(3,5-dnb)2(py)2(H2O)2] {3,5-Hdnb = 3,5-dinitrobenzoic acid; py = pyridine} was isolated in two polymorphs, in space groups C2/c (1) and P21/c (2). Single-crystal X-ray diffraction analyses reveal that 1 and 2 are not isostructural in spite of having equal formulas and ligand connectivity. In both structures, the Co(II) centers adopt octahedral {CoN2O4} geometries filled by pairs of mutually trans terminal 3,5-dnb, py, and water ligands. However, the structures of 1 and 2 disclose distinct packing patterns driven by strong intermolecular O-H···O hydrogen bonds, leading to their 0D→2D (1) or 0D→1D (2) extension. The resulting two-dimensional layers and one-dimensional chains were topologically classified as the sql and 2C1 underlying nets, respectively. By means of DFT theoretical calculations, the energy variations between the polymorphs were estimated, and the binding energies associated with the noncovalent interactions observed in the crystal structures were also evaluated. The study of the direct-current magnetic properties, as well as ab initio calculations, reveal that both 1 and 2 present a strong easy-plane magnetic anisotropy (D > 0), which is larger for the latter polymorph (D is found to exhibit values between +58 and 117 cm(-1) depending on the method). Alternating current dynamic susceptibility measurements show that these polymorphs exhibit field-induced slow relaxation of the magnetization with Ueff values of 19.5 and 21.1 cm(-1) for 1 and 2, respectively. The analysis of the whole magnetic data allows the conclusion that the magnetization relaxation in these polymorphs mainly takes place through a virtual excited state (Raman process). It is worth noting that despite the notable difference between the supramolecular networks of 1 and 2, they exhibit almost identical magnetization dynamics. This fact suggests that the relaxation process is intramolecular in nature and that the virtual state involved in the

  15. Surface morphological and photoelectrochemical studies of ZnS thin films developed from single source precursors by aerosol assisted chemical vapour deposition

    Ehsan, Muhammad Ali [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Peiris, T.A. Nirmal; Wijayantha, K.G. Upul [Department of Chemistry, Loughborough University, Loughborough, LE11 3TU (United Kingdom); Khaledi, Hamid [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Ming, Huang Nay [Faculty of Science, Department of Physics, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Misran, Misni; Arifin, Zainudin [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mazhar, Muhammad, E-mail: [Faculty of Science, Department of Chemistry, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)


    Zinc sulphide (ZnS) thin films have been deposited on fluorine-doped tin oxide-coated conducting glass substrates at 375, 425 and 475 °C temperatures from single source adduct precursors [Zn(S{sub 2}CNCy{sub 2}){sub 2}(py)] (1) [where, Cy = cyclohexyl, py = pyridine] and [Zn{S_2CN(CH_2Ph)(Me)}{sub 2}(py)] (2) [where, Ph = Phenyl, Me = Methyl] using aerosol assisted chemical vapour deposition (AACVD). The precursor complexes have been characterized by microanalysis, infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, X-ray single crystal and thermogravimetric analysis. Thermal analysis showed that both precursors (1) and (2) undergo thermal decomposition at 375 °C to produce ZnS residues. The deposited ZnS films have been characterized by X-ray diffraction and energy dispersive X-ray spectroscopy. Scanning electron microscopic studies indicated that the surface morphology of ZnS films strongly depends on the nature of the precursor and the deposition temperature, regardless of marginal variation in thermal stability of the precursors. Direct band gap energies of 3.36 and 3.40 eV have been estimated from the ultraviolet–visible spectroscopy for the ZnS films fabricated from precursors (1) and (2), respectively. The current–voltage characteristics recorded under air mass 1.5 illumination confirmed that the deposited ZnS thin films are photoactive under anodic bias conditions. Furthermore, the photoelectrochemical (PEC) results indicate that these synthesised single source precursors are suitable for obtaining ZnS thin films by AACVD method. The ZnS thin film electrode prepared in this study are very promising for solar energy conversion and optoelectronic applications. The PEC properties of ZnS electrodes prepared from (2) are superior to that of the ZnS electrode prepared from precursor (1). - Highlights: • Synthesis and characterization of zinc dithiocarbamate pyridine adducts. • ZnS photo electrodes have been fabricated using aerosol

  16. Textures, trace elements, and Pb isotopes of sulfides from the Haopinggou vein deposit, southern North China Craton: implications for discrete Au and Ag-Pb-Zn mineralization

    Li, Zhan-Ke; Li, Jian-Wei; Cooke, David R.; Danyushevsky, Leonid; Zhang, Lejun; O'Brien, Hugh; Lahaye, Yann; Zhang, Wen; Xu, Hai-Jun


    The Haopinggou deposit in the Xiong'ershan district, southern margin of the North China Craton, comprises numerous Au and Ag-Pb-Zn veins hosted in metamorphic rocks of the Late Archean to early Paleoproterozoic Taihua Group. Two stages of mineralization have been recognized: Stage 1 pyrite-quartz veins and Stage 2 Pb-Zn-sulfide veins. Some pyrite-quartz veins are surrounded or cut by Pb-Zn-sulfide veins, others occur as independent veins. Six generations of pyrite have been identified at Haopinggou: Py1 to Py3 in Stage 1 and Py4 to Py6 in Stage 2. Pyrites from Stage 1 are enriched in Au, As, Co, Ni, and Bi, whereas Stage 2 pyrites contain higher Ag, Pb, Zn, Sn, and Sb. Invisible Au mostly occurs as lattice-bound gold in Py2 (up to 92 ppm Au) and Py3 (up to 127 ppm Au) and has a close relationship with As. Native Au grains are also present in Py3 and likely resulted from mobilization and reprecipitation of the invisible Au previously locked in the precursor pyrite. This view is supported by extensive plastic deformation in Stage 1 pyrite as revealed by electron backscatter diffraction analysis. In Stage 2, Ag is mostly present as lattice-bound silver closely associated with Sb in galena (up to 798 ppm Ag). A variety of silver minerals are also present as inclusions within galena or as interstitial grains. These silver minerals were likely formed via Ag-Cu exchange reaction between tetrahedrite and galena or represent exsolution from galena due to a temperature decrease. Pb isotopic compositions differ remarkably between Stage 1 and Stage 2 sulfides, indicating different sources of lead. Pb in Stage 2 Pb-Zn-sulfide veins is consistent with the Haopinggou porphyry close to the veins. The field, textural, compositional, and lead isotopic data led us to conclude that the early gold-bearing pyrite-quartz veins and late silver-bearing Pb-Zn-sulfide veins likely formed from distinct fluid systems related to discrete mineralization events. Our study suggests that Au and Ag

  17. Syntheses and Crystal Structures of Mono- and Binuclear Copper( Ⅱ ) Mixed-ligand Complexes Involving Schiff Base


    The mononuclear copper(Ⅱ) complex [Cu(L)(2-AP)] 1 and binuclear copper(Ⅱ)complex [Cu(L)(py)]2 2 (L = C1oH1 1O5NS, taurine o-vanillin, py = prydine, 2-AP = 2-aminopyridine)with mixed ligand have been synthesized and characterized by X-ray diffraction method. Crystal data for 1: orthorhombic, space group Pbca with a = 11.921(4), b = 15.816(6), c = 17.076(6) (A), V=3219.7(19) (A)3, C15H17CuN3O5S, Z = 8, Mr = 414.92, Dc = 1.712 g/cm3,μ(MoKα) = 1.520 mm-1,F(000) = 1704, the final R = 0.0300 and wR = 0.0705 for 2840 observed reflections with I > 2σ(I);and crystal data for 2: monoclinic, space group P21/c with a = 7.929(3), b = 17.038(5), c = 11.734(4)(A), β = 98.162(6)°, V = 1569.1 (9) (A)3, C15H16CuN2O5S, Z = 4, Mr = 399.90, Dc = 1.693 g/cm3, F(000)= 820,μ(MoKα) = 1.554 mm-1, the final R = 0.0351 and wR = 0.0848 for 2767 observed reflections (I > 2o(I)). The molecular structure of complex 1 consists of one tetra-coordinated Cu(Ⅱ) atom generating a slightly distorted square plane, and a one-dimensional chain structure is formed by intermolecular hydrogen bonds. Complex 2 consists of a diphenolic hydroxyl O-bridged binuclear copper(Ⅱ) structure. The crystal structures of complexes 1 and 2 reveal that the coordinate copper centers are bound to both nitrogen and oxygen atom donors. The usual N,O-trans arrangement of ligands is observed in both cases.

  18. Self-assembly of metal-organic coordination polymers constructed from a bent dicarboxylate ligand: diversity of coordination modes, structures, and gas adsorption.

    Yang, Wenbin; Lin, Xiang; Blake, Alexander J; Wilson, Claire; Hubberstey, Peter; Champness, Neil R; Schröder, Martin


    We have synthesized five new metal-organic coordination polymers incorporating the bent ligand H(2)hfipbb [4,4'-(hexafluoroisopropylidene)bis(benzoic acid)] with different transition metal ions and co-ligands via solvothermal reactions to give [Zn(2)(hfipbb)(2)(py)(2)] x DMF (1), [Zn(2)(hfipbb)(2)(4,4'-bipy)(H(2)O)] (2), [Zn(2)(hfipbb)(2)(bpdab)].2DMF (3), [Cd(2)(hfipbb)(2)(DMF)(2)] x 2 DMF (4), and [Co(hfipbb)(dpp)] x MeOH (5) (py = pyridine, 4,4'-bipy = 4,4'-bipyridine, bpdab = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, dpp = 1,3-di(4-pyridyl)propane). Compound 1 displays a 2-fold 2D-->2D parallel interpenetrated layer network with one-dimensional (1D) helical channels, while 3 exhibits a three-dimensional pillared helical-layer open framework of alpha-Po topology based upon binuclear paddlewheel units. In compounds 2 and 5, binuclear motifs with double carboxylate bridges are linked by hfipbb(2-) ligands into a 1D ribbon, which are further assembled into two-dimensional non-interpenetrated (4,4) layers via bipyridyl co-ligands. However, the different bridging modes of hfipbb(2-) ligands and the different disposition of the coordinated co-ligands around metal ions result in subtle differences in the final architecture. Thus, 2 is based on a binuclear cluster node, double-stranded hfipbb(2-) linkers, and single-stranded 4,4'-bipy linkers, while 5 is based on a binuclear cluster node and hfipbb(2-) and dpp linkers which are both double-stranded. Among these compounds, the Cd(II) complex 4 is possibly the most interesting because it represents a rare example in which metal centers are linked by carboxylate groups into infinite chains further joined together by hfipbb(2-) spacers to form a 2D network with tubular helical channels. All these coordination polymers exhibit low solvent-accessible volumes. Both 3 and 4 retain structural integrity and permanent microporosity upon evacuation of guest molecules, with hydrogen uptakes of 0.57 and 0.78 wt %, respectively, at

  19. Assessment of the. pi. -acceptor capability of selected ligands based on the photoelectron spectra of ruthenium ammine complexes

    Shepherd, R. E.; Proctor, A.; Henderson, W.W.; Myser, T.K.


    ESCA spectra have been recorded for a series of Ru/sup II/ and Ru/sup III/ ammine complexes of general formula ((NH/sub 3/)/sub 5/RuL)X/sub n/ (X/sup -/ = PF/sub 6//sup -/, Cl/sup -/). Binding energy regions of the C/sub 1s/, Ru/sub 3d3/s/, and Ru/sub 3d5/s/, and Ru/sub 3p3/2/ photopeaks were studied. Binding energies were determined by using nonlinear-least-squares curve fitting. equal to the binding energy difference for (C/sub 1s/ - Ru/sub 3d5/2/) has been used to assign a fractional increase in charge at the Ru/sup II/ center when L = a series of ..pi..-acceptor ligands: N-methylpyrazinium (CH/sub 3/pz/sup +/), CO dimethyl acetylenedicarboxylate ester (dmad), CO, pyrazine (pz), pyridine (py), and CH/sub 3/CN. Authentic Ru/sup II/ and Ru/sup III/ oxidation states were assumed for (Ru(en)/sub 3/)ZnCl/sub 4/, = 5.1 eV, and (Ru(NH/sub 3/)/sub 6/)Cl/sub 3/, = 2.5 eV, respectively. The ..pi..-acceptor order and effective Ru oxidation state were determined to be as follows: CH/sub 3/pz/sup +/, 3.01 > CO, 2.88 > dmad, 2.73 > pz, 2.51 > CH/sub 3/CN, 2.31 > py, 2.20. was also found to be linear in the value of E/sub 1/2/ for the (NH/sub 3/)/sub 5/RuL/sup 3+/2+/ couple. ..pi..-Donor ligands exhibit little influence on for Ru/sup III/ derivatives; = 2.4 +/- 0.1 eV for 3,5-dimethylpyrazole, 4-(dimethylamino)pyridine, and 4-aminopyridine.

  20. Finding new equilibria: Directed synthesis of lanthanide materials via sodium azide mediated pathways

    Moore, Brian Freeman

    This dissertation covers the synthesis and characterization of three unique classes of lanthanide materials produced exclusively by the addition of sodium azide (NaN3) into solution based lanthanide reactions. The products were achieved through transmetallation and redox reactions between rare earth chalcogenolate reagents (Lnx(EPh)y), NaN 3 and elemental chalcogenides (E = O, S, Se, Te). The products displayed atypical structural and physical properties including; unique coordination geometries, high nuclearities, tunable detonation/deflagration, strong NIR emissions, and unexpected magnetic ordering behaviors. The introduction of NaN3, Na2O, Cd, elemental Se and Te into Ln (EPh)2 and Ln(EPh)3 pyridine (py) solutions led to the production of (py) 2Na2(EPh)2 and 5 structurally distinct azide encapsulated rare earth clusters; (Py) 10Sm6O2(N3)16Na2, (py)8Ln6O2(N3)12(SePh) 2, (py)10Ln6O2(Se2) 2(N3)10 (Ln=Er, Ho), and (py)16Sm 8Se(O2)Na2(Te2)6(N 3)8. Each system was encapsulated by a variety of azide bridging moieties, while exhibiting a [Ln]/[N3] dependent correlation with detonation and deflagration temperatures. The inclusion of NaN3 in Ln(SePh)3 pyridine solutions with elemental Se, led to the discovery of the (py)16Ln17 NaSe18(SePh)16; (Ln= Ce, Pr, and Nd). Emission studies of the Nd17 analogue, revealed a 35% quantum efficiency for the 4F3/2 - 4I11/2 transition (1070 nm emission), and a near solid state emission intensity for the 4F3/2 → 4I15/2 transition (1822 nm emission). The novel Eu(EPh)4Na2•2DME; (E=S,Se), specimens were synthesized by the combination of Eu(EPh)2 with NaN3 in dimethoxyethane (DME). The europium coordination sphere was solvent free and resembles the coordinations of europium monochalcogenides (EuE). Comparative structural analysis and magnetic susceptibility studies of the Eu3+ product, ((py)6Eu2(mu4-S 2)2(OC6F5)2) revealed paramagnetic ordering at low temperature for Eu(EPh)4Na2•2DME; (E=S,Se), while ferrimagnetic ordering was found

  1. Modular reweighting software for statistical mechanical analysis of biased equilibrium data

    Sindhikara, Daniel J.


    version supersede the previous version?: Yes Nature of problem: While equilibrium reweighting is ubiquitous, there are no public programs available to perform the reweighting in the general case. Further, specific programs often suffer from many library dependencies and numerical instability. Solution method: This package is written in a modular format that allows for easy applicability of reweighting in the general case. Modules are small, numerically stable, and require minimal libraries. Reasons for new version: Some minor bugs, some upgrades needed, error analysis added. has been replaced by “”. This new program performs all the functions of its predecessor while being versatile enough to handle other types of histograms and probability analysis. “” was added. This script performs basic bootstrap resampling allowing for error analysis of data. “” was added. This program computes the averages and standard deviations of multiple distributions, making error analysis (e.g. from bootstrap resampling) easier to visualize. WRE.cpp was slightly modified purely for cosmetic reasons. The manual was updated for clarity and to reflect version updates. Examples were removed from the manual in favor of online tutorials (packaged examples remain). Examples were updated to reflect the new format. An additional example is included to demonstrate error analysis. Running time: Preprocessing scripts 1-5 minutes, WHAM engine <1 minute, postprocess script ∼1-5 minutes.

  2. Towards a Unified Architecture for Data-Intensive Seismology in VERCE

    Klampanos, I.; Spinuso, A.; Trani, L.; Krause, A.; Garcia, C. R.; Atkinson, M.


    Modern seismology involves managing, storing and processing large datasets, typically geographically distributed across organisations. Performing computational experiments using these data generates more data, which in turn have to be managed, further analysed and frequently be made available within or outside the scientific community. As part of the EU-funded project VERCE (, we research and develop a number of use-cases, interfacing technologies to satisfy the data-intensive requirements of modern seismology. Our solution seeks to support: (1) familiar programming environments to develop and execute experiments, in particular via Python/ObsPy, (2) a unified view of heterogeneous computing resources, public or private, through the adoption of workflows, (3) monitoring the experiments and validating the data products at varying granularities, via a comprehensive provenance system, (4) reproducibility of experiments and consistency in collaboration, via a shared registry of processing units and contextual metadata (computing resources, data, etc.) Here, we provide a brief account of these components and their roles in the proposed architecture. Our design integrates heterogeneous distributed systems, while allowing researchers to retain current practices and control data handling and execution via higher-level abstractions. At the core of our solution lies the workflow language Dispel. While Dispel can be used to express workflows at fine detail, it may also be used as part of meta- or job-submission workflows. User interaction can be provided through a visual editor or through custom applications on top of parameterisable workflows, which is the approach VERCE follows. According to our design, the scientist may use versions of Dispel/workflow processing elements offered by the VERCE library or override them introducing custom scientific code, using ObsPy. This approach has the advantage that, while the scientist uses a familiar tool, the resulting

  3. Ab initio study of the n-π* electronic transition in acetone: Symmetry-forbidden vibronic spectra

    Liao, D. W.; Mebel, A. M.; Hayashi, M.; Shiu, Y. J.; Chen, Y. T.; Lin, S. H.


    Ab initio calculations of geometry and vibrational frequencies of the first singlet excited 1A2(1A″) state of acetone corresponding to the n-π* electronic transition have been carried out at the CASSCF/6-311G** level. The major geometry changes in this state as compared to the ground state involve CO out-of-plane wagging, CO stretch and torsion of the methyl groups, and the molecular symmetry changes from C2v to Cs. The most pronounced frequency changes in the 1A″ state are the decrease of the CO stretch frequency v3 by almost 500 cm-1 and the increase of the CH3 torsion frequency v12 from 22 to 170 cm-1. The optimized geometries and normal modes are used to compute the normal mode displacements which are applied for calculations of Franck-Condon factors. Transition matrix elements over the one-electron electric field operator at various atomic centers calculated at the state-average CASSCF/6-311+G** level are used to compute vibronic couplings between the ground 1A1, 1A2, and Rydberg 1B2(n-3s), 2 1A1(n-3py), 2 1A2(n-3px), 2 1B2(n-3pz), and 1B1(n-3dxy) electronic states, and the Herzberg-Teller expansion of the electronic wave function is applied to derive the transition dipole moment for 1A1→1A2 as a function of normal coordinates. The results show that the intensity for this transition is mostly borrowed from the allowed 1A1-1B2(n-3s) transition due to vibronic coupling between 1A2 and 1B2 through normal modes Q20, Q22, and Q23 and, to some extent, from the 1A1-1B1 transition due to Q19 (CO in-plane bend) which couples 1A2 with 1B1(n-3dxy). The calculated total oscillator strength for the n-π* transition through the intensity-borrowing mechanism, 3.62×10-4, is in close agreement with the experimental value of 4.14×10-4. Ninety-four percent of the oscillator strength comes from the perpendicular component (b1 inducing modes) and 6% from the parallel component (b2 modes). Calculated spectral origin, 30 115 cm-1 at the MRCI/6-311G** level, underestimates

  4. A Pyridine-Based Ligand with Two Hydrazine Functions for Lanthanide Chelation: Remarkable Kinetic Inertness for a Linear, Bishydrated Complex.

    Bonnet, Célia S; Laine, Sophie; Buron, Frédéric; Tircsó, Gyula; Pallier, Agnès; Helm, Lothar; Suzenet, Franck; Tóth, Éva


    To study the influence of hydrazine functions in the ligand skeleton, we designed the heptadentate HYD ligand (2,2',2″,2‴-(2,2'-(pyridine-2,6-diyl)bis(2-methylhydrazine-2,1,1-triyl)) tetraacetic acid) and compared the thermodynamic, kinetic, and relaxation properties of its Ln(3+) complexes to those of the parent pyridine (Py) analogues without hydrazine (Py = 2,6-pyridinebis(methanamine)-N,N,N',N'-tetraacetic acid). The protonation constants of HYD were determined by pH-potentiometric measurements, and assigned by a combination of UV-visible and NMR spectroscopies. The protonation sequence is rather unusual and illustrates that small structural changes can strongly influence ligand basicity. The first protonation step occurs on the pyridine nitrogen in the basic region, followed by two hydrazine nitrogens and the carboxylate groups at acidic pH. Contrary to Py, HYD self-aggregates through a pH-dependent process (from pH ca. 4). Thermodynamic stability constants have been obtained by pH-potentiometry and UV-visible spectrophotometry for various Ln(3+) and physiological cations (Zn(2+), Ca(2+), Cu(2+)). LnHYD stability constants show the same trend as those of LnDTPA complexes along the Ln(3+) series, with log K = 18.33 for Gd(3+), comparable to the Py analogue. CuHYD has a particularly high stability (log K > 19) preventing its determination from pH-potentiometric measurements. The stability constant of CuPy was also revisited and found to be underestimated in previous studies, highlighting that UV-visible spectrophotometry is often indispensable to obtain reliable stability constants for Cu(2+) chelates. The dissociation of GdL, assessed by studying the Cu(2+)-exchange reaction, occurs mainly via an acid-catalyzed process, with limited contribution from direct Cu(2+) attack. The kinetic inertness of GdHYD is remarkable for a linear bishydrated chelate; the 25-fold increase in the dissociation half-life with respect to the monohydrated commercial contrast agent

  5. Inorganic lead and calcium interact positively in activation of calmodulin.

    Kern, M; Wisniewski, M; Cabell, L; Audesirk, G


    Calmodulin is a ubiquitous calcium-binding protein that mediates many of the intracellular actions of Ca2+ ions. The calcium-binding sites of calmodulin consist of four EF-hand motifs; full activation of calmodulin normally occurs when all four sites are occupied by Ca2+. Inorganic lead (PY2+) has been shown to activate calmodulin at total lead concentrations similar to the concentrations of Ca2+ required for activation (Goldstein and Ar, 1983; Habermann et al., 1983), but the free Pb2+ concentrations required for calmodulin activation have not been determined. In addition, it is possible that activation may occur with different sites occupied by different divalent cations, for example Ca2+ and Pb2+. We investigated the ability of free Pb2+, alone or in combination with Ca2+, to activate calmodulin. In aqueous media, N-phenyl-1-naphthylamine (NPN) and 8-anilino-1-naphthalenesulfonate (ANS) show increased fluorescence when bound to hydrophobic regions of proteins. This increased fluorescence has been used to monitor the conformational change that occurs during calmodulin activation (LaPorte et al., 1980). In the presence of calmodulin, both Ca2+ and Pb2+ stimulated increased fluorescence of NPN and ANS. Threshold and EC50 free metal concentrations were approximately 100 nM and 450-500 nM, respectively, for Ca2+ and 100 pM and 400-550 pM, respectively, for Pb2+. Fluorescence was enhanced by combinations of low concentrations of free Ca2+ and Pb2+; for example, as little as 20 pM free Pb2+ enhanced fluorescence in combination with 200 nM free Ca2+. The activity of the PDE1 isoform of cyclic nucleotide phosphodiesterase is stimulated by Ca2+/calmodulin (Wang et al., 1990). In the presence of calmodulin, we found that Ca2+ and Pb2+ activated calmodulin-stimulated PDE activity, with threshold and EC50 free metal concentrations of approximately 200 nM and 1200 nM, respectively, for Ca2+ and 300 pM and 430 pM, respectively, for Pb2+. PDE activity was stimulated by

  6. Synthesis and characterization of homo- and heterovalent tetra- hexa- hepta- and decanuclear manganese clusters using pyridyl functionalized beta-diketone, carboxylate and triethanolamine ligands.

    Langley, Stuart K; Chilton, Nicholas F; Massi, Massimiliano; Moubaraki, Boujemaa; Berry, Kevin J; Murray, Keith S


    The syntheses and characterizations are reported for six new homo- and heterovalent manganese clusters, utilizing pyridyl functionalized beta-diketones ligands. The reaction of the trinuclear complex [Mn3O(O2CPh)6(H2O)(Py)2] with 1,3-di(pyridine-2-yl)propane-1,3-dione (dppdH) in CH2Cl2 resulted in a mixed-valence Mn3(II)Mn6(III)Mn(IV) decanuclear cluster of formula [Mn10O7(dppd)3(O2CPh)11] x 4 CH2Cl2 (1). The structure of the core of 1 is based upon a centred tricapped trigonal prism. Reacting Mn(BF4)2 x xH2O with dppdH and triethylamine (NEt3) in CH2Cl2-MeOH gave a rare, homoleptic hexanuclear cluster of formula [Mn(II)6(dppd)8][BF4]4 (2) which has a triangular based core. Reaction of Mn(Y)2 x xH2O, Y = NO3(-) or BF4(-), with dppdH or 1-phenyl-3-(2-pyridyl)propane-1,3-dione (pppdH) in the presence of triethanolamine (teaH3) and NEt3 gave a heptanuclear 'disc' like manganese core of general formula [Mn(II)7(X)6(tea)(OH)3][Y]2 x solv (3) X = pppd- or dppd- and Y = NO3(-) or BF4(-). The addition of N-(2-pyridinyl)acetoacetamide (paaH) to Mn(Y)2 x 4 H2O Y = NO3(-) or ClO4(-) in MeOH gave a second divalent heptanuclear cluster with a 'disc'-like core of general formula [Mn7(paa)6(OMe)6][X]2 x solv (4) (X = NO3(-) or ClO4(-)), whilst the addition of paaH to a mixture of Mn(NO3)2 x 4 H2O, teaH3 and NEt3 in CH2Cl2-MeOH resulted in the formation of a mixed-valence Mn2(II)Mn2(III) tetranuclear 'butterfly' complex of formula [Mn4(paa)4(teaH)2][NO3]2 x 2 MeOH x 2 CH2Cl2 (5). Compound 5 displays the rare Mn(II/III) oxidation state distribution of the body positions being Mn(II) while the wing tips are Mn(III). The in situ formation of the tetranuclear [Mn4(teaH)2(teaH2)2(O2C(CH3)3)2][O2C(CH3)3]2 'butterfly' complex followed by the addition of Mn(O2CMe)2 x 4 H2O resulted in a mixed-valence Mn4(II)Mn(III)Mn(IV) hexanuclear species of formula [Mn6O2(teaH2)4(O2CMe)4][NO3]2[O2CMe] x CH2Cl2 x MeOH x 2 H2O (6). The core of 6 displays a face sharing dicubane topology. Compounds 1 and

  7. Mineralization and trace element distribution in pyrite using EMPA in exploration drill holes from Cheshmeh Zard gold district, Khorasan Razavi Province, Iran

    Zahra Alaminia


    -bearing pyrite stage with sericite, chalcedony and quartz. The pyrite isframboidal.. 4. Finally, a carbonate-dominated stage. The pyrite is euhedral to anhedral and coarse grained. The Au concentration in Stages 2 and 3 pyrite is higher than that in Stage 4 pyrite. Conclusions The gangue mineral assemblages of carbonate, chlorite, quartz, and minor sericite and potassium feldspar in the ore-forming process of the CheshmehZard gold district suggest that the pH value of the hydrothermal fluids was near neutral to slightly acid (approximately 4.5 to 5.3 under 250 to 300 °C and 1 kbar conditions and that gold would be transported mainly as Au(HS2- (Stefansson and Seward, 2004. Three types of pyrite based on the chemical composition have been investigated: As- bearing pyrite, Ti-V - bearing pyrite and pure or barren pyrite. EMPA analyses of the pyrite in gold veins show maximum concentrations of As (3.62 wt.%, Ti (3.91 wt.% and V (0.53 wt.% respectively. The occurrence of the gold is usually associated with arsenian pyrite and Ti-V - bearing pyrite. Veinlets of the Py1 coexisting with arseno-pyrite and gold Py2 implies the substitution of sulfur by arsenic. Gold precipitated under relatively reducing conditions in framboidal pyrite. Py3 formed prior to barren pyrite (IV. References Alaminia, Z., Karimpour, M.H., Homam, S.M. and Finger, F., 2013a. The magmatic record in the Arghash region, NE Iran, and tectonic implications. International Journal of Earth Sciences, 102(6:1603-1625. Ashrafpour, E., Ansdell, K.M. and Alirezaei, S., 2012. Hydrothermal fluid evolution and ore genesis in the Arghash epithermal gold prospect, northeastern Iran. Journal of Asian Earth Sciences, 51(1:30–44. Butler, I.B. and Rickard, D., 2000. Framboidal pyrite formation via the oxidation of iron (II monosulfide by hydrogen sulphide. Geochimica et Cosmochimica Acta, 64(15: 2665–2672. Samadi, M., 2001. Exploration in Arghash Gold Prospect. Geological Survey of Iran, unpublished report, Tehran, 73 pp. (in