WorldWideScience

Sample records for ccaat-binding complex coordinates

  1. Coordination Approaches for Complex Software Systems

    NARCIS (Netherlands)

    Bosse, T.; Hoogendoorn, M.; Treur, J.

    2006-01-01

    This document presents the results of a collaboration between the Vrije Universiteit Amsterdam, Department of Artificial Intelligence and Force Vision to investigate coordination approaches for complex software systems. The project was funded by Force Vision.

  2. Polyoxometalate coordinated transition metal complexes as ...

    Indian Academy of Sciences (India)

    Keywords. Heptamolybdate type polyoxometalate cluster anion; transition metal coordination complexes; ... industrial chemistry. This oxidation can be divided into three categories: (i) the cleavage of the C=C bond by using the surface of the metal oxide, e.g., osmium or .... supported cobalt complexes (catalysts 1 and 2) pro-.

  3. Deriving force field parameters for coordination complexes

    DEFF Research Database (Denmark)

    Norrby, Per-Ola; Brandt, Peter

    2001-01-01

    The process of deriving molecular mechanics force fields for coordination complexes is outlined. Force field basics are introduced with an emphasis on special requirements for metal complexes. The review is then focused on how to set up the initial model, define the target, refine the parameters...

  4. Deriving force field parameters for coordination complexes

    DEFF Research Database (Denmark)

    Norrby, Per-Ola; Brandt, Peter

    2001-01-01

    The process of deriving molecular mechanics force fields for coordination complexes is outlined. Force field basics are introduced with an emphasis on special requirements for metal complexes. The review is then focused on how to set up the initial model, define the target, refine the parameters......, and validate the final force field, Alternatives to force field derivation are discussed briefly....

  5. Encoding of coordination complexes with XML.

    Science.gov (United States)

    Vinoth, P; Sankar, P

    2017-09-01

    An in-silico system to encode structure, bonding and properties of coordination complexes is developed. The encoding is achieved through a semantic XML markup frame. Composition of the coordination complexes is captured in terms of central atom and ligands. Structural information of central atom is detailed in terms of electron status of valence electron orbitals. The ligands are encoded with specific reference to the electron environment of ligand centre atoms. Behaviour of ligands to form low or high spin complexes is accomplished by assigning a Ligand Centre Value to every ligand based on the electronic environment of ligand centre atom. Chemical ontologies are used for categorization purpose and to control different hybridization schemes. Complexes formed by the central atoms of transition metal, non-transition elements belonging to s-block, p-block and f-block are encoded with a generic encoding platform. Complexes of homoleptic, heteroleptic and bridged types are also covered by this encoding system. Utility of the encoded system to predict redox electron transfer reaction in the coordination complexes is demonstrated with a simple application. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Seventeen-coordinate actinide helium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kaltsoyannis, Nikolas [School of Chemistry, The University of Manchester (United Kingdom)

    2017-06-12

    The geometries and electronic structures of molecular ions featuring He atoms complexed to actinide cations are explored computationally using density functional and coupled cluster theories. A new record coordination number is established, as AcHe{sub 17}{sup 3+}, ThHe{sub 17}{sup 4+}, and PaHe{sub 17}{sup 4+} are all found to be true geometric minima, with the He atoms clearly located in the first shell around the actinide. Analysis of AcHe{sub n}{sup 3+} (n=1-17) using the quantum theory of atoms in molecules (QTAIM) confirms these systems as having closed shell, charge-induced dipole bonding. Excellent correlations (R{sup 2}>0.95) are found between QTAIM metrics (bond critical point electron densities and delocalization indices) and the average Ac-He distances, and also with the incremental He binding energies. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Higher coordination numbers of metals in isolated complexes

    International Nuclear Information System (INIS)

    Wells, A.F.

    1988-01-01

    The material pertaining to island complexes with polydentate ligands where transition and rare earth metals have coordination numbers from 7 to 10 is generalized. The coordination of different ligands in the complexes of these metals depending on the chemical composition and structure of chelating ligand, as well as characteristics of the central atom, is considered

  8. Transition Metal Complexes Coordinated by Water Soluble Phosphane Ligands: How Cyclodextrins Can Alter the Coordination Sphere?

    Directory of Open Access Journals (Sweden)

    Michel Ferreira

    2017-01-01

    Full Text Available The behaviour of platinum(II and palladium(0 complexes coordinated by various hydrosoluble monodentate phosphane ligands has been investigated by 31P{1H} NMR spectroscopy in the presence of randomly methylated β-cyclodextrin (RAME-β-CD. This molecular receptor can have no impact on the organometallic complexes, induce the formation of phosphane low-coordinated complexes or form coordination second sphere species. These three behaviours are under thermodynamic control and are governed not only by the affinity of RAME-β-CD for the phosphane but also by the phosphane stereoelectronic properties. When observed, the low-coordinated complexes may be formed either via a preliminary decoordination of the phosphane followed by a complexation of the free ligand by the CD or via the generation of organometallic species complexed by CD which then lead to expulsion of ligands to decrease their internal steric hindrance.

  9. Stability of complex coacervate core micelles containing metal coordination polymer

    NARCIS (Netherlands)

    Yan, Y.; Keizer, de A.; Cohen Stuart, M.A.; Drechsler, M.; Besseling, N.A.M.

    2008-01-01

    We report on the stability of complex coacervate core micelles, i.e., C3Ms (or PIC, BIC micelles), containing metal coordination polymers. In aqueous solutions these micelles are formed between charged-neutral diblock copolymers and oppositely charged coordination polymers formed from metal ions and

  10. Fluorescent zinc–terpyridine complex containing coordinated ...

    Indian Academy of Sciences (India)

    Unknown

    Chem. Soc.) 2. Farrel N 1989 Transition metal complexes as drug and chemotherapeutic agents (Dordrecht: Kluwer Academic) vol 11. 3. Sigman D S 1986 Acc. Chem. Res. 19 180; (b) Liu F, Meadows K A and McMillin D R 1993. J. Am. Chem. Soc. 115 6699. 4. Prince R H 1979 Advances in inorganic and radiochemistry ...

  11. On the π Coordination of Organometallic Fullerene Complexes

    Directory of Open Access Journals (Sweden)

    Bertha Molina

    2011-06-01

    Full Text Available Novel organometallic complexes of fullerene C80 and aryl ligands were simulated. The nature and characteristics of this family of complexes involving π coordination between the fullerene and a metal centre have been studied from a theoretical point of view. We are particularly interested in complexes where η6 coordination is present, this being the strangest manifestation of known coordinations, and thus we have studied several known and simulated compounds of this kind in order to understand the lack of examples. The presence of other η6 or η5 ligands on the opposite side seems to be an important element aiding the stabilization of these complexes, also inducing the conductive and semiconductive behaviour of the studied species.

  12. Chiral transfer in coordination complexes: towards molecular materials.

    Science.gov (United States)

    Crassous, Jeanne

    2009-03-01

    In this critical review we present examples of coordination complexes with efficient chiral transfer determining stereochemistry at the metal centre and throughout the overall molecular assembly. The general features controlling the transmission of chirality are presented. The transfer of chirality are considered here with the special purpose of obtaining a molecular material displaying a particular property or function. Coordination complexes in fields as diverse as chiral luminescent materials, homochiral MOFs, chiral liquid crystals, enantioselective sensors, chiroptical switches, and magnetochiral compounds are presented (162 references).

  13. 3d and 4d coordination complexes and coordination polymers involving electroactive tetrathiafulvalene containing ligands

    OpenAIRE

    Pointillart , Fabrice; Golhen , Stéphane; Cador , Olivier; Ouahab , Lahcène

    2013-01-01

    International audience; The "through bond" approach has been recently developed to increase the interaction between the mobile π and localized d electrons in multifunctional molecular materials involving tetrathiafulvalene-based ligands. This article reviews the 3d and 4d coordination complexes and polymers elaborated from a library of tetrathiafulvalene derivatives containing ligands obtained recently in our group. The different synthetic ways of the complexes are highlighted as well as thei...

  14. Metallacyclopentadienes: structural features and coordination in transition metal complexes

    International Nuclear Information System (INIS)

    Dolgushin, Fedor M; Yanovsky, Aleksandr I; Antipin, Mikhail Yu

    2004-01-01

    Results of structural studies of polynuclear transition metal complexes containing the metallacyclopentadiene fragment are overviewed. The structural features of the complexes in relation to the nature of the substituents in the organic moiety of the metallacycles, the nature of the transition metals and their ligand environment are analysed. The main structural characteristics corresponding to different modes of coordination of metallacyclopentadienes to one or two additional metal centres are revealed.

  15. Osmium and cobalt complexes incorporating facially coordinated N ...

    Indian Academy of Sciences (India)

    reactivity. Fascinating chemistry of transition metal complexes incorporating ligands that are capable of binding the metal centre in facial manner, enhanced the interest on the synthesis of new ..... effective core potential functions were used. All energy .... We contemplated to examine the coordination mode of the same ...

  16. Osmium and cobalt complexes incorporating facially coordinated N ...

    Indian Academy of Sciences (India)

    Administrator

    SUPPLEMENTARY MATERIALS. Osmium and cobalt complexes incorporating facially coordinated N,N,O donor azo-imine ligands: Redox and catalytic properties. Poulami Pattanayak, a. Debprasad Patra, a. Jahar Lal Pratihar, a. Andrew Burrows,. Mary F. Mahon b and Surajit Chattopadhyay* a a. Department of Chemistry ...

  17. Osmium and cobalt complexes incorporating facially coordinated N ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 125; Issue 1. Osmium and cobalt complexes incorporating facially coordinated N,N,O donor azo-imine ligands: Redox and catalytic properties. Poulami Pattanayak Debprasad Patra Jahar Lal Pratihar Andrew Burrows Mary F Mahon Surajit Chattopadhyay. Volume ...

  18. Reversible five-coordinate ⇄ six-coordinate transformation in cobalt(II) complexes

    Science.gov (United States)

    Xiao, Linda; Bhadbhade, Mohan; Baker, Anthony T.

    2018-04-01

    The heterocyclic ligands 2,6-bis(pyrazol-1-yl)pyridine (L1) and 2,6-bis(benzimidazol-2-yl)pyridine (L2) and their cobalt(II) complexes were synthesized. The blue five-coordinate complex [Co(L1)Cl2] isolated initially from the reaction mixture rapidly absorbed water vapour from the atmosphere to yield the pink six-coordinate complex [Co(L1)(H2O)3]Cl2. This change is reversible upon desiccation or transferring [Co(L1)(H2O)3]Cl2 into acetonitrile. The five coordinate complex [Co(L2)Cl2], however, remains stable under similar conditions. The structures of the complexes [Co(L1)Cl2], [Co(L1)(H2O)3]Cl2 and [Co(L2)Cl2] have been determined by x-ray crystallography. The magnetic susceptibilities and the electronic spectra for [Co(L1)Cl2], [Co(L2)Cl2] and [Co(L1)(H2O)3]Cl2 are presented.

  19. Six-Coordinate Ln(III Complexes with Various Coordination Geometries Showing Distinct Magnetic Properties

    Directory of Open Access Journals (Sweden)

    Mei Guo

    2018-01-01

    Full Text Available The syntheses, structural characterization, and magnetic properties of three lanthanide complexes with formulas [Ln(L13] (Ln = Dy (1Dy; Er (1Er; and [Dy(L22] (2Dy were reported. Complexes 1Dy and 1Er are isostructural with the metal ion in distorted trigonal-prismatic coordination geometry, but exhibit distinct magnetic properties due to the different shapes of electron density for DyIII (oblate and ErIII (prolate ions. Complex 1Dy shows obvious SMM behavior under a zero direct current (dc field with an effective energy barrier of 31.4 K, while complex 1Er only features SMM behavior under a 400 Oe external field with an effective energy barrier of 23.96 K. In stark contrast, complex 2Dy with the octahedral geometry only exhibits the frequency dependence of alternating current (ac susceptibility signals without χ″ peaks under a zero dc field.

  20. Energetic lanthanide complexes: coordination chemistry and explosives applications

    International Nuclear Information System (INIS)

    Manner, V W; Barker, B J; Sanders, V E; Laintz, K E; Scott, B L; Preston, D N; Sandstrom, M; Reardon, B L

    2014-01-01

    Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

  1. Copper ions and coordination complexes as novel carbapenem adjuvants

    OpenAIRE

    Djoko, Karrera Y.; Achard, Maud E. S.; Phan, Minh-Duy; Lo, Alvin W.; Miraula, Manfredi; Prombhul, Sasiprapa; Hancock, Steven J.; Peters, Kate M.; Sidjabat, Hanna; Harris, Patrick N.; Mitić, Nataša; Walsh, Timothy R.; Anderson, Gregory J.; Shafer, William M.; Paterson, David L.

    2017-01-01

    Carbapenem-resistant Enterobacteriaceae are an urgent threat to global human health. These organisms produce β-lactamases with carbapenemase activity, such as the metallo-β-lactamase NDM-1, which is notable due to its association with mobile genetic elements and the lack of a clinically useful inhibitor. Here we examined the ability of copper to inhibit the activity of NDM-1 and explored the potential of a copper coordination complex as a mechanism to efficiently deliver copper as an adjuvant...

  2. Facile Preparation of Hybrid Zinc Porphyrin Dendrimer Using Coordination Complex

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Go-Eun; Shin, Eun Ju [Sunchon National University, Suncheon (Korea, Republic of)

    2016-03-15

    Porphyrins and metalloporphyrins have been investigated extensively due to their important role in natural photosynthesis, strong absorption in visible region, good light-harvesting properties, unique photophysical and electrochemical properties, and the development of simple synthetic routes for various derivatives. Dendrimers have globular structure with branches of repeating units and wide diversity of the architecture because their size, shape, and functionalities can be tailored. Numerous dendrimers have been designed and synthesized for various applications ranging from catalyst to drug delivery. Both pyridine dendrons Py-PD and Py-AD were successfully coordinated at axial position on central zinc metal cation in zinc porphyrin dendrimers ZnP-AD, ZnP-AD2, or ZnP-AD4. Therefore, it was proven that the formation of axial coordination complex between metal-centered dendrimer and ligand-containing dendron provides another facile method for the preparation of new hybrid dendrimer.

  3. Design of magnetic coordination complexes for quantum computing.

    Science.gov (United States)

    Aromí, Guillem; Aguilà, David; Gamez, Patrick; Luis, Fernando; Roubeau, Olivier

    2012-01-21

    A very exciting prospect in coordination chemistry is to manipulate spins within magnetic complexes for the realization of quantum logic operations. An introduction to the requirements for a paramagnetic molecule to act as a 2-qubit quantum gate is provided in this tutorial review. We propose synthetic methods aimed at accessing such type of functional molecules, based on ligand design and inorganic synthesis. Two strategies are presented: (i) the first consists in targeting molecules containing a pair of well-defined and weakly coupled paramagnetic metal aggregates, each acting as a carrier of one potential qubit, (ii) the second is the design of dinuclear complexes of anisotropic metal ions, exhibiting dissimilar environments and feeble magnetic coupling. The first systems obtained from this synthetic program are presented here and their properties are discussed.

  4. Coordination phenomena of cationic uranium(iv) complexes

    International Nuclear Information System (INIS)

    Rohwer, H.E.

    1974-12-01

    The coordination properties of the cationic uranium(IV) complexes UCl 3 + , UCl 2 2+ , UCl 3+ , and U 4+ were studied in a non-aqueous medium in the presence of perchlorate as counterion which, however, proved to coordinate to a much greater extent than expected. The strong neutral ligand, HMPA, could successively displace some of the perchlorates. An electrostatic model for the U(CIO 4 ) 4 -HMPA-acetone system compared favourably with the actual results. This emphasized the high ionic content in the bonding with actenoid cations, even with such a high charge as +4 . These conclusions are in agreement with studies 75 in which nitrate acts as counter ion. Correspondingly the uranium (IV) chemistry is characterized by the absence of typical 3d-organometallic chemistry, for example, strong bonding with CO, P(Phi) 3 etc, which strongly depends on covalent bonding. This stresses the fact that the d and f orbitals are not readily available for strong bond formation with the actenoids. 76

  5. Coordination chemistry of homoleptic actinide(IV)-thiocyanate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Tyler J.; Wilson, Richard E. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL (United States)

    2015-10-26

    The synthesis, X-ray crystal structure, vibrational and optical spectroscopy for the eight-coordinate thiocyanate compounds, [Et{sub 4}N]{sub 4}[Pu{sup IV}(NCS){sub 8}], [Et{sub 4}N]{sub 4}[Th{sup IV}(NCS){sub 8}], and [Et{sub 4}N]{sub 4}[Ce{sup III}(NCS){sub 7}(H{sub 2}O)] are reported. Thiocyanate was found to rapidly reduce plutonium to Pu{sup III} in acidic solutions (pH<1) in the presence of NCS{sup -}. The optical spectrum of [Et{sub 4}N][SCN] containing Pu{sup III} solution was indistinguishable from that of aquated Pu{sup III} suggesting that inner-sphere complexation with [Et{sub 4}N][SCN] does not occur in water. However, upon concentration, the homoleptic thiocyanate complex [Et{sub 4}N]{sub 4}[Pu{sup IV}(NCS){sub 8}] was crystallized when a large excess of [Et{sub 4}N][NCS] was present. This compound, along with its U{sup IV} analogue, maintains inner-sphere thiocyanate coordination in acetonitrile based on the observation of intense ligand-to-metal charge-transfer bands. Spectroscopic and crystallographic data do not support the interaction of the metal orbitals with the ligand π system, but support an enhanced An{sup IV}-NCS interaction, as the Lewis acidity of the metal ion increases from Th to Pu. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Phosphorescent 2-, 3- and 4-coordinate cyclic (alkyl)(amino)carbene (CAAC) Cu(i) complexes.

    Science.gov (United States)

    Hamze, Rasha; Jazzar, Rodolphe; Soleilhavoup, Michele; Djurovich, Peter I; Bertrand, Guy; Thompson, Mark E

    2017-08-08

    The photophysical properties of several Cu(i) complexes coordinated with cyclic (alkyl)(amino)carbene (CAAC) ligands were examined. All the compounds were found to be phosphorescent, regardless of whether they are 2-, 3- or 4-coordinated. Aggregate and excimer emission were observed from 2-coordinate CAAC-CuCl derivatives in methylcyclohexane solution. Emission from the complex 4-coordinated with a trispyrazolylborate ligand is red-shifted with respect to both the chloro-derivative and an analogous complex with an NHC ligand.

  7. Mathematical model and coordination algorithms for ensuring complex security of an organization

    Science.gov (United States)

    Novoseltsev, V. I.; Orlova, D. E.; Dubrovin, A. S.; Irkhin, V. P.

    2018-03-01

    The mathematical model of coordination when ensuring complex security of the organization is considered. On the basis of use of a method of casual search three types of algorithms of effective coordination adequate to mismatch level concerning security are developed: a coordination algorithm at domination of instructions of the coordinator; a coordination algorithm at domination of decisions of performers; a coordination algorithm at parity of interests of the coordinator and performers. Assessment of convergence of the algorithms considered above it was made by carrying out a computing experiment. The described algorithms of coordination have property of convergence in the sense stated above. And, the following regularity is revealed: than more simply in the structural relation the algorithm, for the smaller number of iterations is provided to those its convergence.

  8. Coordination equilibria in the complex formation of guanylurea with Cu

    Indian Academy of Sciences (India)

    Wintec

    scheme 1) in the ab- sence and in the presence of the simplest amino acid, glycine (GlyH) as the auxiliary ligand in aqueous solution at 25 ± 1°C at a fixed ionic strength,. I = 0⋅1 mol.dm–3 (NaNO3). Varied modes of metal ion coordination by ...

  9. Distributed detection of communities in complex networks using synthetic coordinates

    International Nuclear Information System (INIS)

    Papadakis, H; Fragopoulou, P; Panagiotakis, C

    2014-01-01

    Various applications like finding Web communities, detecting the structure of social networks, and even analyzing a graph’s structure to uncover Internet attacks are just some of the applications for which community detection is important. In this paper, we propose an algorithm that finds the entire community structure of a network, on the basis of local interactions between neighboring nodes and an unsupervised distributed hierarchical clustering algorithm. The novelty of the proposed approach, named SCCD (standing for synthetic coordinate community detection), lies in the fact that the algorithm is based on the use of Vivaldi synthetic network coordinates computed by a distributed algorithm. The current paper not only presents an efficient distributed community finding algorithm, but also demonstrates that synthetic network coordinates could be used to derive efficient solutions to a variety of problems. Experimental results and comparisons with other methods from the literature are presented for a variety of benchmark graphs with known community structure, derived from varying a number of graph parameters and real data set graphs. The experimental results and comparisons to existing methods with similar computation cost on real and synthetic data sets demonstrate the high performance and robustness of the proposed scheme. (paper)

  10. [Coordinating complex nursing care: building a guidance tool for cancer patients, to direct them towards the coordination nurse].

    Science.gov (United States)

    Froger, Raphael; Allenet, Benoit; Guillem, Pascale

    2017-03-01

    Introduction : following the 2009-2013 Cancer Plan, the experimental oncology nursing coordination (IDEC) showed a positive impact on the fluidity of care pathways. The 2014-2019 cancer plan guides their mission to complex cases. The objective of this study is to build a tool to facilitate the recruitment of patients likely to experience a complex path. Method : two phases have formed this research. The first one collected the elements of the dimensions that can predict the complexity of the care path, by focus group. The second consisted of reduction and selection of priority items and to estimate their importance by the Delphi method. Results : from the 12 selected items, two are recognized as a significant risk scoring, seven probably correlated with a complex pathway and three unrelated to the complexity of the pathways. Discussion : later this instrument would be validated by a test sample to evaluate its psychometric properties, metrological and feasibility.

  11. Osmium and cobalt complexes incorporating facially coordinated N ...

    Indian Academy of Sciences (India)

    The ligands which bind the transition metal ion in a predictable way play ... was purified by thin-layer chromatography on silica gel. A green band ..... gands, L. −. , (X-ray structure). The unipositive charge of the complex cation, [(L)2Co]. +. , 7, was satisfied by one. ClO. −. 4 ion. These complexes are soluble in common ...

  12. Equilibrium between Different Coordination Geometries in Oxidovanadium(IV) Complexes

    Science.gov (United States)

    Ugone, Valeria; Garribba, Eugenio; Micera, Giovanni; Sanna, Daniele

    2015-01-01

    In this laboratory activity, the equilibrium between square pyramidal and octahedral V(IV)O[superscript 2+] complexes is described. We propose a set of experiments to synthesize and characterize two types of V(IV)O[superscript 2+] complexes. The experiment allows great flexibility and may be effectively used at a variety of levels and the activity…

  13. Structure of Coordination Complexes: The Synergy between NMR ...

    African Journals Online (AJOL)

    Cl2 and Ti(β-diketonato)2(biphen) complexes as determined by density functional theory (DFT) methods and the application of the Boltzmann equation, are in agreement with crystal structures and variable temperature NMR results. Secondly ...

  14. Coordination equilibria in the complex formation of guanylurea with ...

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/jcsc/120/04/0377-0390. Keywords. CuII; guanylurea; glycinate; mixed-ligand complex; formation constants. Abstract. Combined pH-metric and spectrophotometric investigations on the complex formation equilibria of CuII with guanylurea (H 2 1 NC(=O) 2NH.C(=3NH) 4NH2), hereafter, GuH, ...

  15. Coordination Chemistry of Homoleptic Actinide(IV)-Thiocyanate Complexes.

    Science.gov (United States)

    Carter, Tyler J; Wilson, Richard E

    2015-10-26

    The synthesis, X-ray crystal structure, vibrational and optical spectroscopy for the eight-coordinate thiocyanate compounds, [Et4 N]4 [Pu(IV) (NCS)8 ], [Et4 N]4 [Th(IV) (NCS)8 ], and [Et4 N]4 [Ce(III) (NCS)7 (H2 O)] are reported. Thiocyanate was found to rapidly reduce plutonium to Pu(III) in acidic solutions (pHcoordination in acetonitrile based on the observation of intense ligand-to-metal charge-transfer bands. Spectroscopic and crystallographic data do not support the interaction of the metal orbitals with the ligand π system, but support an enhanced An(IV) -NCS interaction, as the Lewis acidity of the metal ion increases from Th to Pu. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Proton exchange in acid-base complexes induced by reaction coordinates with heavy atom motions

    Energy Technology Data Exchange (ETDEWEB)

    Alavi, Saman, E-mail: saman.alavi@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council of Canada, Ontario, K1A 0R6 (Canada); Taghikhani, Mahdi [Department of Chemistry, Sharif Institute of Technology, Tehran (Iran, Islamic Republic of)

    2012-06-19

    Highlights: Black-Right-Pointing-Pointer Proton exchange in acid-base complexes is studied. Black-Right-Pointing-Pointer The structures, binding energies, and normal mode vibrations are calculated. Black-Right-Pointing-Pointer Transition state structures of proton exchange mechanism are determined. Black-Right-Pointing-Pointer In the complexes studied, the reaction coordinate involves heavy atom rocking. Black-Right-Pointing-Pointer The reaction coordinate is not simply localized in the proton movements. - Abstract: We extend previous work on nitric acid-ammonia and nitric acid-alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid-strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400 cm{sup -1}. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm{sup -1}. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

  17. Proton exchange in acid–base complexes induced by reaction coordinates with heavy atom motions

    International Nuclear Information System (INIS)

    Alavi, Saman; Taghikhani, Mahdi

    2012-01-01

    Highlights: ► Proton exchange in acid–base complexes is studied. ► The structures, binding energies, and normal mode vibrations are calculated. ► Transition state structures of proton exchange mechanism are determined. ► In the complexes studied, the reaction coordinate involves heavy atom rocking. ► The reaction coordinate is not simply localized in the proton movements. - Abstract: We extend previous work on nitric acid–ammonia and nitric acid–alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid–strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are −1 . This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm −1 . Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

  18. Carboxylate-bridged Cu(II) coordination polymeric complex ...

    Indian Academy of Sciences (India)

    SABITHAKALA THATITURI

    An in vitro antibacterial activity study of BIGH and Cu-BIG showed moderate activity against Bacillus subtilis. ..... ure 10. Thermogram of the complex shows only one stage of weight loss between 250 and 275 .... ligands: Syntheses, structures, and physical properties. CrystEngComm 17 3181. 15. Fan L M, Zhang X T, Sun Z, ...

  19. The coordination and atom transfer chemistry of titanium porphyrin complexes

    Energy Technology Data Exchange (ETDEWEB)

    Hays, James Allen [Iowa State Univ., Ames, IA (United States)

    1993-11-05

    Preparation, characterization, and reactivity of (η2- alkyne)(meso-tetratolylpoprphrinato)titanium(II) complexes are described, along with inetermetal oxygen atom transfer reactions involving Ti(IV) and Ti(III) porphyrin complexes. The η2- alkyne complexes are prepared by reaction of (TTP)TiCl2 with LiAlH4 in presence of alkyne. Structure of (OEP)Ti(η2-Ph-C≡C-Ph) (OEP=octaethylporphryin) was determined by XRD. The compounds undergo simple substitution to displace the alkyne and produce doubly substituted complexes. Structure of (TTP)Ti(4-picoline)2 was also determined by XRD. Reaction of (TTP)Ti=O with (OEP)Ti-Cl yields intermetal O/Cl exchange, which is a one-electron redox process mediated by O atom transfer. Also a zero-electron redox process mediated by atom transfer is observed when (TTP)TiCl2 is reacted with (OEP)Ti=O.

  20. Coordination equilibria in the complex formation of guanylurea with Cu

    Indian Academy of Sciences (India)

    Wintec

    puter program SCOGS,9 run on a Pentium-4 com- puter. Refined values of the constants (table 1) corresponding to the minimum standard deviations were accepted for ..... nar CuII complexes with amino acids and small pep- tide ligands can be tentatively assigned from the shift of the absorption maxima of CuII in such com-.

  1. Osmium and cobalt complexes incorporating facially coordinated N ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 125; Issue 1. Osmium and cobalt complexes incorporating ... Mary F Mahon2 Surajit Chattopadhyay1. Department of Chemistry, University of Kalyani, Kalyani 741235, India; Department of Inorganic Chemistry, University of Bath, Claverton Down, Bath, BA27AY, UK ...

  2. Biphenolate Iron (II) Complexes with Intramolecularly Coordinating Nitrogen Lewis Bases

    NARCIS (Netherlands)

    Koten, G. van; Brandts, J.A.M.; Janssen, M.D.; Hogerheide, M.P.; Boersma, J.; Spek, A.L.

    1999-01-01

    The synthesis and characterisation of a novel Fe(II) bisphenolate complex [Fe(OC{6}H{4}CH{2}NMe{2}-2){2}]{2} (1) from [Na(OC{6}H{4}CH{2}NMe{2}-2)] and anhydrous FeCl{2} is reported. The solid state structure has been elucidated by single crystal X-ray analysis and shows a dimeric structure with two

  3. Structure of Coordination Complexes: The Synergy between NMR ...

    African Journals Online (AJOL)

    NICO

    product of oxidative addition of methyl iodide to [Rh(acac). (P(OPh)3)2]. Figure 6 displays the three types of TS structures that have been reported for the oxidative addition of methyl iodide to square planar rhodium(I) complexes (especially the Monsanto catalyst [Rh(CO)2I2]–).55,72 Two transition states lead to trans addi-.

  4. Supramolecular coordination and antimicrobial activities of constructed mixed ligand complexes

    Science.gov (United States)

    El-Sonbati, A. Z.; Diab, M. A.; El-Bindary, A. A.; Abou-Dobara, M. I.; Seyam, H. A.

    2013-03-01

    A novel series of copper(II) and palladium(II) with 4-derivatives benzaldehyde pyrazolone (Ln) were synthesized. The mixed ligand complexes were prepared by using 1,10-phenanthroline (Phen) as second ligand. The structure of these complexes was identified and confirm by elemental analysis, molar conductivity, UV-Vis, IR and 1H NMR spectroscopy and magnetic moment measurements as well as thermal analysis. The ligand behaves as a neutral bidentate ligand through ON donor sites. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(Ln)2]Cl2ṡ2H2O. Schiff bases (Ln) were tested against bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested compounds have antibacterial activity against S. aureus, B. cereus and K. pneumoniae.

  5. Variable Denticity in Carboxylate Binding to the Uranyl Coordination Complexes

    International Nuclear Information System (INIS)

    Groenewold, G.S.; De Jong, Wibe A.; Oomens, Jos; Van Stipdonk, Michael J.

    2010-01-01

    Tris-carboxylate complexes of the uranyl (UO2)2+ cation with acetate and benzoate were generated using electrospray ionization mass spectrometry, and then isolated in a Fourier transformion cyclotron resonance mass spectrometer. Wavelength-selective infrared multiple photon dissociation (IRMPD) of the tris-acetatouranyl anion resulted in a redox elimination of an acetate radical, which was used to generate an IR spectrum that consisted of six prominent absorption bands. These were interpreted with the aid of density functional theory calculations in terms of symmetric and antisymmetric -CO2 stretches of both the monodentate and bidentate acetate, CH3 bending and umbrella vibrations, and a uranyl O-U-O asymmetric stretch. The comparison of the calculated and measured IR spectra indicated that the tris-acetate complex contained two acetate ligands bound in a bidentate fashion, while the third acetate was monodentate. In similar fashion, the tris-benzoate uranyl anion was formed and photodissociated by loss of a benzoate radical, enabling measurement of the infrared spectrum that was in close agreement with that calculated for a structure containing one monodentate, and two bidentate benzoate ligands.

  6. Coordinatively unsaturated ruthenium complexes as efficient alkyneazide cycloaddition catalysts

    KAUST Repository

    Lamberti, Marina

    2012-01-23

    The performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azidealkyne cycloaddition reactions that afford the 1,2,3- triazole products. The scope of the Cp*Ru(PiPr 3)Cl precatalyst was investigated for terminal alkynes leading to new 1,5-disubstituted 1,2,3-triazoles in high yields. Mechanistic studies were conducted and revealed a number of proposed intermediates. Cp*Ru- (PiPr3)(2-HCCPh)Cl was observed and characterized by 1H, 13C, and 31P NMR at temperatures between 273 and 213 K. A rare example of N,N-κ2-phosphazide complex, Cp*Ru(κ2- iPr3PN3Bn)Cl, was fully characterized, and a single-crystal X-ray diffraction structure was obtained. DFT calculations describe a complete map of the catalytic reactivity with phenylacetylene and/or benzylazide. © 2012 American Chemical Society.

  7. Plutonium(IV) complexation by diglycolamide ligands - coordination chemistry insight into TODGA-based actinide separations

    NARCIS (Netherlands)

    Reilly, S.D.; Gaunt, A.J.; Scott, B.L.; Modolo, G.; Iqbal, M.; Verboom, Willem; Sarsfield, M.J.

    2012-01-01

    Complexation of Pu(IV) with TMDGA, TEDGA, and TODGA diglycolamide ligands was followed by vis-NIR spectroscopy. A crystal structure determination reveals that TMDGA forms a 1:3 homoleptic Pu(IV) complex with the nitrate anions forced into the outer coordination sphere

  8. Variable coordinating activity of sulfur in silver(I) complexes with ...

    Indian Academy of Sciences (India)

    Variable coordinating activity of sulfur in silver(I) complexes with thiophene based N. 1. -substituted thiosemicarbazones: First case of thiopheneyl-thione sulfur bridging in a dinuclear complex. REKHA SHARMAa,b, TARLOK S LOBANAa,∗, MANVIR KAURa, NEERAJ THATHAIa,. GEETA HUNDALa, JERRY P JASINSKIc ...

  9. Direct measurement and modulation of single-molecule coordinative bonding forces in a transition metal complex

    DEFF Research Database (Denmark)

    Hao, Xian; Zhu, Nan; Gschneidtner, Tina

    2013-01-01

    remain a daunting challenge. Here we demonstrate an interdisciplinary and systematic approach that enables measurement and modulation of the coordinative bonding forces in a transition metal complex. Terpyridine is derived with a thiol linker, facilitating covalent attachment of this ligand on both gold...... substrate surfaces and gold-coated atomic force microscopy tips. The coordination and bond breaking between terpyridine and osmium are followed in situ by electrochemically controlled atomic force microscopy at the single-molecule level. The redox state of the central metal atom is found to have......Coordination chemistry has been a consistently active branch of chemistry since Werner's seminal theory of coordination compounds inaugurated in 1893, with the central focus on transition metal complexes. However, control and measurement of metal-ligand interactions at the single-molecule level...

  10. Surprising Coordination Geometry Differences in Ce(IV)- and Pu(IV)-Maltol Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Berkeley National Laboratory; Raymond, Kenneth; Szigethy, Geza; Xu, Jide; Gorden, Anne E.V.; Teat, Simon J.; Shuh, David K.; Raymond, Kenneth N.

    2008-02-12

    As part of a study to characterize the detailed coordination behavior of Pu(IV), single crystal X-ray diffraction structures have been determined for Pu(IV) and Ce(IV) complexes with the naturally-occurring ligand maltol (3-hydroxy-2-methyl-pyran-4-one) and its derivative bromomaltol (5-bromo-3-hydroxy-2-methyl-pyran-4-one). Although Ce(IV) is generally accepted as a structural analog for Pu(IV), and the maltol complexes of these two metals are isostructural, the corresponding bromomaltol complexes are strikingly different with respect to ligand orientation about the metal ion: All complexes exhibit trigonal dodecahedral coordination geometry but the Ce(IV)-bromomaltol complex displays an uncommon ligand arrangement not mirrored in the Pu(IV) complex, although the two metal species are generally accepted to be structural analogs.

  11. Parent Perspective on Care Coordination Services for Their Child with Medical Complexity

    Directory of Open Access Journals (Sweden)

    Rhonda G. Cady

    2017-06-01

    Full Text Available The overarching goal of care coordination is communication and co-management across settings. Children with medical complexity require care from multiple services and providers, and the many benefits of care coordination on health and patient experience outcomes have been documented. Despite these findings, parents still report their greatest challenge is communication gaps. When this occurs, parents assume responsibility for aggregating and sharing health information across providers and settings. A new primary-specialty care coordination partnership model for children with medical complexity works to address these challenges and bridge communication gaps. During the first year of the new partnership, parents participated in focus groups to better understand how they perceive communication and collaboration between the providers and services delivering care for their medically complex child. Our findings from these sessions reflect the current literature and highlight additional challenges of rural families, as seen from the perspective of the parents. We found that parents appreciate when professional care coordination is provided, but this is often the exception and not the norm. Additionally, parents feel that the local health system’s inability to care for their medically complex child results in unnecessary trips to urban-based specialty care. These gaps require a system-level approach to care coordination and, consequently, new paradigms for delivery are urgently needed.

  12. Low-Complexity MMSE Precoding for Coordinated Multipoint with Per-Antenna Power Constraint

    DEFF Research Database (Denmark)

    Kim, Tae Min; Sun, Fan; Paulraj, Arogyaswami

    2013-01-01

    We propose a low-complexity minimum mean square error (MMSE) transmit filter design for the coordinated beamforming (CB) in the coordinated multipoint (CoMP) under the practical per-antenna power constraint (PAPC). The proposed design is based on the non-linear Gauss-Seidel type algorithm in which...... the transmit filters for given receive filters are computed by iteratively updating the beamformer of each transmit antenna using simple closed-form expressions. The proposed approach can significantly reduce the overall complexity of the alternating optimization while preserving the optimality in the MSE...

  13. A manganese oxido complex bearing facially coordinating trispyridyl ligands--is coordination geometry crucial for water oxidation catalysis?

    Science.gov (United States)

    Berends, Hans-Martin; Manke, Anne-Marie; Näther, Christian; Tuczek, Felix; Kurz, Philipp

    2012-05-28

    In this work the synthesis of the novel manganese complex [Mn(2)(III,III)(tpdm)(2)(μ-O)(μ-OAc)(2)](2+) (1) is reported, containing two manganese centres ligated to the unusual, facially coordinating, all-pyridine ligand tpdm (tris(2-pyridyl)methane). The geometric and electronic properties of complex 1 were characterised by X-ray crystallography, vibrational (IR and Raman) and optical spectroscopy (UV/Vis and MCD). Cyclic voltammograms of 1 showed a quasi-reversible oxidation event at 950 mV and an irreversible reduction wave at -250 mV vs. Ag/Ag(+). The redox behaviour of the compound was investigated in detail by UV/Vis- and X-band EPR-spectroelectrochemistry. Both electrochemical (+1200 mV) and chemical (tBuOOH) oxidations transform 1 into the singly oxidized di-μ-oxido species [Mn(2)(III,IV)(tpdm)(2)(μ-O)(2)(μ-OAc)](2+). Further electrochemical oxidation at the same potential results in the removal of a second electron to obtain a Mn(2)(IV,IV)-species. The ability of compound 1 to evolve O(2) was studied using different reaction agents. While reactions with both hydrogen peroxide and peroxomonosulfate yield O(2), homogeneous water-oxidation using Ce(IV) was not observed. Nevertheless, the oxidation reactions of 1 are very interesting model processes for oxidation state (S-state) transitions of the natural manganese water-oxidation catalyst in photosynthesis. However, despite its favourable coordination geometry and multielectron redox chemistry, complex 1 fails to be a catalytically active model for natural water-oxidation.

  14. Mechanics of metal-catecholate complexes: The roles of coordination state and metal types

    Science.gov (United States)

    Xu, Zhiping

    2013-01-01

    There have been growing evidences for the critical roles of metal-coordination complexes in defining structural and mechanical properties of unmineralized biological materials, including hardness, toughness, and abrasion resistance. Their dynamic (e.g. pH-responsive, self-healable, reversible) properties inspire promising applications of synthetic materials following this concept. However, mechanics of these coordination crosslinks, which lays the ground for predictive and rational material design, has not yet been well addressed. Here we present a first-principles study of representative coordination complexes between metals and catechols. The results show that these crosslinks offer stiffness and strength near a covalent bond, which strongly depend on the coordination state and type of metals. This dependence is discussed by analyzing the nature of bonding between metals and catechols. The responsive mechanics of metal-coordination is further mapped from the single-molecule level to a networked material. The results presented here provide fundamental understanding and principles for material selection in metal-coordination-based applications. PMID:24107799

  15. Multifunctionality of organometallic quinonoid metal complexes: surface chemistry, coordination polymers, and catalysts.

    Science.gov (United States)

    Kim, Sang Bok; Pike, Robert D; Sweigart, Dwight A

    2013-11-19

    Quinonoid metal complexes have potential applications in surface chemistry, coordination polymers, and catalysts. Although quinonoid manganese tricarbonyl complexes have been used as secondary building units (SBUs) in the formation of novel metal-organometallic coordination networks and polymers, the potentially wider applications of these versatile linkers have not yet been recognized. In this Account, we focus on these diverse new applications of quinonoid metal complexes, and report on the variety of quinonoid metal complexes that we have synthesized. Through the use of [(η(6)-hydroquinone)Mn(CO)3](+), we are able to modify the surface of Fe3O4 and FePt nanoparticles (NPs). This process occurs either by the replacement of oleylamine with neutral [(η(5)-semiquinone)Mn(CO)3] at the NP surface, or by the binding of anionic [(η(4)-quinone)Mn(CO)3](-) upon further deprotonation of [(η(5)-semiquinone)Mn(CO)3] at the NP surface. We have demonstrated chemistry at the intersection of surface-modified NPs and coordination polymers through the growth of organometallic coordination polymers onto the surface modified Fe3O4 NPs. The resulting magnetic NP/organometallic coordination polymer hybrid material exhibited both the unique superparamagnetic behavior associated with Fe3O4 NPs and the paramagnetism attributable to the metal nodes, depending upon the magnetic range examined. By the use of functionalized [(η(5)-semiquinone)Mn(CO)3] complexes, we attained the formation of an organometallic monolayer on the surface of highly ordered pyrolitic graphite (HOPG). The resulting organometallic monolayer was not simply a random array of manganese atoms on the surface, but rather consisted of an alternating "up and down" spatial arrangement of Mn atoms extending from the HOPG surface due to hydrogen bonding of the quinonoid complexes. We also showed that the topology of metal atoms on the surface could be controlled through the use of quinonoid metal complexes. A quinonoid

  16. Detecting coordinated regulation of multi-protein complexes using logic analysis of gene expression

    Directory of Open Access Journals (Sweden)

    Yeates Todd O

    2009-12-01

    Full Text Available Abstract Background Many of the functional units in cells are multi-protein complexes such as RNA polymerase, the ribosome, and the proteasome. For such units to work together, one might expect a high level of regulation to enable co-appearance or repression of sets of complexes at the required time. However, this type of coordinated regulation between whole complexes is difficult to detect by existing methods for analyzing mRNA co-expression. We propose a new methodology that is able to detect such higher order relationships. Results We detect coordinated regulation of multiple protein complexes using logic analysis of gene expression data. Specifically, we identify gene triplets composed of genes whose expression profiles are found to be related by various types of logic functions. In order to focus on complexes, we associate the members of a gene triplet with the distinct protein complexes to which they belong. In this way, we identify complexes related by specific kinds of regulatory relationships. For example, we may find that the transcription of complex C is increased only if the transcription of both complex A AND complex B is repressed. We identify hundreds of examples of coordinated regulation among complexes under various stress conditions. Many of these examples involve the ribosome. Some of our examples have been previously identified in the literature, while others are novel. One notable example is the relationship between the transcription of the ribosome, RNA polymerase and mannosyltransferase II, which is involved in N-linked glycan processing in the Golgi. Conclusions The analysis proposed here focuses on relationships among triplets of genes that are not evident when genes are examined in a pairwise fashion as in typical clustering methods. By grouping gene triplets, we are able to decipher coordinated regulation among sets of three complexes. Moreover, using all triplets that involve coordinated regulation with the ribosome

  17. Electrochemically fabricated polypyrrole-cobalt-oxygen coordination complex as high-performance lithium-storage materials.

    Science.gov (United States)

    Guo, Bingkun; Kong, Qingyu; Zhu, Ying; Mao, Ya; Wang, Zhaoxiang; Wan, Meixiang; Chen, Liquan

    2011-12-23

    Current lithium-ion battery (LIB) technologies are all based on inorganic electrode materials, though organic materials have been used as electrodes for years. Disadvantages such as limited thermal stability and low specific capacity hinder their applications. On the other hand, the transition metal oxides that provide high lithium-storage capacity by way of electrochemical conversion reaction suffer from poor cycling stability. Here we report a novel high-performance, organic, lithium-storage material, a polypyrrole-cobalt-oxygen (PPy-Co-O) coordination complex, with high lithium-storage capacity and excellent cycling stability. Extended X-ray absorption fine structure and Raman spectroscopy and other physical and electrochemical characterizations demonstrate that this coordination complex can be electrochemically fabricated by cycling PPy-coated Co(3)O(4) between 0.0 V and 3.0 V versus Li(+)/Li. Density functional theory (DFT) calculations indicate that each cobalt atom coordinates with two nitrogen atoms within the PPy-Co coordination layer and the layers are connected with oxygen atoms between them. Coordination weakens the C-H bonds on PPy and makes the complex a novel lithium-storage material with high capacity and high cycling stability. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Chiral phosphites as ligands in asymmetric metal complex catalysis and synthesis of coordination compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilov, Konstantin N [Department of Chemistry, S.A. Esenin Ryazan State Pedagogical University, Ryazan (Russian Federation); Bondarev, Oleg G; Polosukhin, Aleksei I [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation)

    2004-07-31

    The data published during the last five years on the application of chiral derivatives of phosphorous acid in coordination chemistry and enantioselective catalysis are summarised and discussed. The effect of the nature of these ligands on the structure of metal complexes and on the efficiency of catalytic organic syntheses is shown. Hydroformylation, hydrogenation, allylic substitution and conjugate addition catalysed by transition metal complexes with optically active phosphites and hydrophosphoranes are considered. The prospects for the development of this field of research are demonstrated.

  19. Coordination symmetry determination of some lanthanide complexes by x-ray diffraction

    International Nuclear Information System (INIS)

    Oliveira Paiva Santos, C. de.

    1983-01-01

    The x-ray determination of the crystal and molecular structures of three lanthanide complexes is described. The work is a contribution to the study of the coordination chemistry of lanthanide ions with organic ligands and in particular, it aims to compare the observed point symmetry of the ion environment with spectroscopic predictions. (author)

  20. Spin crossover in Fe(II) complexes with N4S2 coordination

    DEFF Research Database (Denmark)

    Arroyave, Alejandra; Lennartson, Anders; Dragulescu-Andrasi, Alina

    2016-01-01

    A systematic study of a series of Fe(II) complexes with the tetradentate N2S2-binding ligand and NCX− coligands (X = S, Se, BH3) conclusively demonstrates the occurrence of temperature-driven spin crossover (SCO), which is rarely observed for the Fe(II) ion in the N4S2 coordination environment...

  1. Experimental investigation of some coordination complexes using the sup(151)Eu Moessbauer resonance

    International Nuclear Information System (INIS)

    Lal, Asharfi; Rama Reddy, A.; Arvind; Ahmad, Naseer

    1979-01-01

    Several Schiff base complexes containing Eu 151 metal ions have been synthesized and their Moessbauer spectra are recorded using the constant acceleration velocity spectrometer. The least-square analysis method for the evaluation of the hyperfine field coupling constants is adopted using the computer dec system-10. From the systematic analysis of the quadrupole coupling constants (q.c.c.) and isomer shifts it has been established that the coordination number of the metal ion of Bis(acetylacetone) benzidine and thiourea complexes is five, that of bis-vanillin benzidine and bis-salicylaldehyde-o-dianisidine is six, and that of bis-vanillin-o-phenylene diamine is seven. It is also found that the q.c.c. being negative in all these complexes decreases monotonically as the coordination number increases. One unusual aspect of this experimental data is that most of the coordination complexes have very low f-factors whereas the Schiff base complexes studied here have a fairly high recoilless fractions. Attempts are in progress to synthesize and study the Fe Schiff base complexes in place of Eu. (auth.)

  2. The Role of Care Coordinator for Children with Complex Care Needs: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Rowan Hillis

    2016-05-01

    Full Text Available Introduction: This systematic review seeks to identify the intended components of the role of care coordinator for children with complex care needs and the factors that determine its composition in practice. Theory and methods: The initial search identified 1,157 articles, of which 37 met the inclusion criteria. They were quality assessed using the SIGN hierarchy of evidence structure. Results: Core components of the role include: coordination of care needs, planning and assessment, specialist support, emotional support, administration and logistics and continuing professional development. Influencing factors on the role include the external environment (political and socio-economic, the internal environment (organisational structure and funding protocols, the skills, qualifications and experience of the coordinator, the family circumstances and the nature of the interaction between the care coordinator and the family. Discussion: The lack of consistent terminology creates challenges and there is a need for greater consensus on this issue. Organisations and healthcare professionals need to recognise the extent to which contextual factors influence the role of a care coordinator in practice and plan accordingly. Despite evidence that suggests that the role is pivotal in ensuring that care needs are sustained, there remains great variability in the understanding of the role of a care coordinator for this population. Conclusions: As the provision of care increasingly moves closer to home there is a need for greater understanding of the nature and composition of the interaction between care coordinators and families to determine the extent to which appropriate services are being provided. Further work in this area should take into consideration any potential variance in service provision, for example any potential inequity arising due to geographic location. It is also imperative, where appropriate, to seek the views of children with complex care

  3. ACTIVATION OF ACETYLENE BY COORDINATION TO BIS-TRIPHENYLPHOSPHINE COMPLEX OF Pt(0: DFT STUDY

    Directory of Open Access Journals (Sweden)

    N. N. Gorinchoy

    2009-06-01

    Full Text Available The present work is devoted to the theoretical study of the activation of the acetylene molecule coordinated in the [Pt(PPh32C2H2] complex. By means of DFT calculations it is shown that the geometrical and electronic characteristics of the C2H2 are essentially changed due to its coordination. The subsequent detailed analysis of the molecular orbitals (MO of the active valence zone of this complex allows one to make important conclusion that this activation is being realized mainly due to the orbital back donation of 5d-electronic density from one of the occupied MOs of the complex [Pt(PPh32] to the unoccupied antibonding π*-MO of C2H2.

  4. A Stable Coordination Complex of Rh(IV) in an N,O-Donor Environment

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Shashi B. [Department of Chemistry, Yale University, 225 Prospect; Shopov, Dimitar Y. [Department of Chemistry, Yale University, 225 Prospect; Sharninghausen, Liam S. [Department of Chemistry, Yale University, 225 Prospect; Vinyard, David J. [Department of Chemistry, Yale University, 225 Prospect; Mercado, Brandon Q. [Department of Chemistry, Yale University, 225 Prospect; Brudvig, Gary W. [Department of Chemistry, Yale University, 225 Prospect; Crabtree, Robert H. [Department of Chemistry, Yale University, 225 Prospect

    2015-12-10

    We describe facial and meridional isomers of [RhIII(pyalk)3], as well as meridional [RhIV(pyalk)3]+ {pyalk =2-(2-pyridyl)-2-propanoate}, the first coordination complex in an N,O-donor environment to show a clean, reversible RhIII/IV redox couple and to have a stable Rh(IV) form, which we characterize by EPR and UV–visible spectroscopy as well as X-ray crystallography. The unprecedented stability of the Rh(IV) species is ascribed to the exceptional donor strength of the ligands, their oxidation resistance, and the meridional coordination geometry.

  5. Low complexity non-iterative coordinated beamforming in 2-user broadcast channels

    KAUST Repository

    Park, Kihong

    2010-10-01

    We propose a new non-iterative coordinated beamforming scheme to obtain full multiplexing gain in 2-user MIMO systems. In order to find the beamforming and combining matrices, we solve a generalized eigenvector problem and describe how to find generalized eigenvectors according to the Gaussian broadcast channels. Selected simulation results show that the proposed method yields the same sum-rate performance as the iterative coordinated beamforming method, while maintaining lower complexity by non-iterative computation of the beamforming and combining matrices. We also show that the proposed method can easily exploit selective gain by choosing the best combination of generalized eigenvectors. © 2006 IEEE.

  6. Synthesis, coordination and structure of pentacoordinated oxovanadium(IV) complexes of hippuric and nicotinic acids

    International Nuclear Information System (INIS)

    Kumar, G.; Singh, Ranjana; Singh, N.P.

    1981-01-01

    Pentacoordinated oxovanadium(IV) complexes formed with hippuric acid (VOL 2 ) and nicotinic acid ((VO) 2 L 2 (OH) 2 ) 5 H 2 O have been synthesized and their structures investigated by magnetochemical and spectra (i.r., U.V. and reflectance) measurements. The I.R. studies indicate that in the bis-hippurato complex the carboxylate group itself acts as a bidentate chelating group, whereas, with nicotinic acid, coordination occurs through both the pyridine N and COO - group. Electronic spectra show them to have pentacoordinated structures. Magnetic studies suggest that the complex formed with nicotinic acid possibly has a binuclear structure with subnormal magnetic moment. (author)

  7. Two organoantimony (V) coordination complexes modulated by isomers of trifluoromethylbenzoate ligands: Syntheses, crystal structure, photodegradation properties

    Science.gov (United States)

    Zhang, Xiao-Yin; Cui, Lian-sheng; Zhang, Xia; Jin, Fan; Fan, Yu-Hua

    2017-04-01

    Two organoantimony (V) coordination complexes, namely Ph3Sb(2-tmbc) (1) and Ph3Sb(3-tmbc) (2) (2-tmbc = 2-(trifluoromethyl)benzoic carboxyl, 3-tmbc = 3-(trifluoromethyl)benzoic carboxyl) have been synthesized and characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complexes 1 and 2 show different architectures by the intermolecular hydrogen bonds (Csbnd H⋯F), complex 1 displays an 1D straight chain structure, while complex 2 shows an 1D zigzag chain structure. The photodegradation properties of complexes 1 and 2 has been investigated in organic dyes (RhB, MV, MB) the results indicated that the two complexes are good candidates for the photocatalytic degradation of three dyes. The tentative photocatalytic degradations mechanism is discussed.

  8. Coordination functionalization of graphene oxide with tetraazamacrocyclic complexes of nickel(II): Generation of paramagnetic centers

    International Nuclear Information System (INIS)

    Basiuk, Vladimir A.; Alzate-Carvajal, Natalia; Henao-Holguín, Laura V.; Rybak-Akimova, Elena V.; Basiuk, Elena V.

    2016-01-01

    Highlights: • [Ni(cyclam)] 2+ and [Ni(tet b)] 2+ cations coordinate to carboxylic groups of GO. • The coordination takes place under basic conditions in aqueous-based medium. • The coordination results in the conversion from low-spin to high-spin Ni(II). • Functionalized GO samples were characterized by various instrumental techniques. - Abstract: We describe a novel approach to functionalization of graphene oxide (GO) which allows for a facile generation of paramagnetic centers from two diamagnetic components. Coordination attachment of [Ni(cyclam)] 2+ or [Ni(tet b)] 2+ tetraazamacrocyclic cations to carboxylic groups of GO takes place under basic conditions in aqueous-based reaction medium. The procedure is very straightforward and does not require high temperatures or other harsh conditions. Changing the coordination geometry of Ni(II) from square-planar tetracoordinated to pseudooctahedral hexacoordinated brings about the conversion from low-spin to high-spin state of the metal centers. Even though the content of tetraazamacrocyclic complexes in functionalized GO samples was found to be relatively low (nickel content of ca. 1 wt%, as determined by thermogravimetric analysis, elemental analysis and energy dispersive X-ray spectroscopy), room temperature magnetic susceptibility measurements easily detected the appearance of paramagnetic properties in GO + [Ni(cyclam)] and GO + [Ni(tet b)] nanohybrids, with effective magnetic moments of 1.95 BM and 2.2 BM for, respectively. According to density functional theory calculations, the main spin density is localized at the macrocyclic complexes, without considerable extension to graphene sheet, which suggests insignificant ferromagnetic coupling in the nanohybrids, in agreement with the results of magnetic susceptibility measurements. The coordination attachment of Ni(II) tetraazamacrocycles to GO results in considerable changes in Fourier-transform infrared and X-ray photoelectron spectra, as well as in GO

  9. Multiporphyrin coordination arrays based on complexation of magnesium(II) porphyrins with porphyrinylphosphine oxides.

    Science.gov (United States)

    Atefi, Farzad; McMurtrie, John C; Arnold, Dennis P

    2007-06-07

    Di- and triporphyrin arrays consisting of 5,15-diphenylporphyrinatomagnesium(II) (MgDPP) coordinated to free-base and Ni(II) porphyrinyl mono- and bis-phosphine oxides, as well as the self-coordinating diphenyl[10,20-diphenylporphyrinatomagnesium(II)-5-yl]phosphine oxide [MgDPP(Ph(2)PO)], were synthesised in excellent yields and characterised by various spectroscopic techniques. Phosphine oxides stabilise Mg(II) coordination to porphyrins and the resulting complexes have convenient solubilities, while the Ni(II) complexes exhibit interesting intramolecular fluorescence quenching behaviour. The binding constant of MgDPP to triphenylphosphine oxide (5.3 +/- 0.1 x 10(5) M(-1)) and the very high self-association constant of [MgDPP(Ph(2)PO)] (5.5 +/- 0.5 x 10(8) M(-1)) demonstrate the strong affinity of phosphine oxides towards Mg(II) porphyrins. These complexes are the first strongly bound synthetic Mg(II) multiporphyrin complexes and could potentially mimic the "special pair" in the photosynthetic reaction centre.

  10. Social dilemmas and individual/group coordination strategies in a complex rural land-use game

    Directory of Open Access Journals (Sweden)

    Luis García-Barrios

    2011-09-01

    Full Text Available Strengthening ongoing bottom-up capacity building processes for local and sustainable landscape-level governance is a multi-dimensional social endeavor. One of the tasks involved – participatory rural land use planning – requires more understanding and more awareness among all stakeholders regarding the social dilemmas local people confront when responding to each other’s land-use decisions. In this paper we will analyze and discuss a version of our game SIERRA SPRINGS that is simple to play for any stakeholder that can count to 24, yet entails a complex-coordination land use game – with an extensive and yet finite set of solutions – which can mimic in a stylized form some of the dilemmas landowners could confront in a landscape planning process where there livelihoods are at stake. The game has helped researchers and players observe and reflect on the individual coordination strategies that emerge within a group in response to these stylized dilemmas. This paper (1 develops a game-theoretical approach to cooperation, competition and coordination of land uses in small rural watersheds, (2 describe the goal, rules and mechanics of the game, (3 analyzes the structure of each farms’ solution set vs. the whole watershed’s solution set, (4 derives from them the coordination dilemmas and the risk of coordination failure, (5 describes four individual coordination strategies consistently displayed by players; mapping them in a plane we have called Group-Level Coordination Space, and (6 discusses the strengths, limitations and actual and potential uses of the game both for research and as an introductory tool for stakeholders involved in participatory land use planning.

  11. Investigation of the complex reaction coordinate of acid catalyzed amide hydrolysis from molecular dynamics simulations

    International Nuclear Information System (INIS)

    Zahn, Dirk

    2004-01-01

    The rate-determining step of acid catalyzed peptide hydrolysis is the nucleophilic attack of a water molecule to the carbon atom of the amide group. Therein the addition of the hydroxyl group to the amide carbon atom involves the association of a water molecule transferring one of its protons to an adjacent water molecule. The protonation of the amide nitrogen atom follows as a separate reaction step. Since the nucleophilic attack involves the breaking and formation of several bonds, the underlying reaction coordinate is rather complex. We investigate this reaction step from path sampling Car-Parrinello molecular dynamics simulations. This approach does not require the predefinition of reaction coordinates and is thus particularly suited for investigating reaction mechanisms. From our simulations the most relevant components of the reaction coordinate are elaborated. Though the C···O distance of the oxygen atom of the water molecule performing the nucleophilic attack and the corresponding amide carbon atom is a descriptor of the reaction progress, a complete picture of the reaction coordinate must include all three molecules taking part in the reaction. Moreover, the proton transfer is found to depend on favorable solvent configurations. Thus, also the arrangement of non-reacting, i.e. solvent water molecules needs to be considered in the reaction coordinate

  12. A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Prehna, G.; Stebbins, C

    2007-01-01

    The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3221 and its crystal structure has been solved at 1.9 {angstrom} resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.

  13. A Rac1-GDP Trimer Complex Binds Zinc with Tetrahedral and Octahedral Coordination, Displacing Magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Prehna,G.; Stebbins, E.

    2007-01-01

    The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3{sub 2}21 and its crystal structure has been solved at 1.9 {angstrom} resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.

  14. Prebiotic coordination chemistry: The potential role of transition-metal complexes in the chemical evolution

    Science.gov (United States)

    Beck, M.

    1979-01-01

    In approaching the extremely involved and complex problem of the origin of life, consideration of the coordination chemistry appeared not only as a possibility but as a necessity. The first model experiments appear to be promising because of prebiotic-type synthesis by means of transition-metal complexes. It is especially significant that in some instances various types of vitally important substances (nucleic bases, amino acids) are formed simultaneously. There is ground to hope that systematic studies in this field will clarify the role of transition-metal complexes in the organizatorial phase of chemical evolution. It is obvious that researchers working in the fields of the chemistry of cyano and carbonyl complexes, and of the catalytic effect of transition-metal complexes are best suited to study these aspects of the attractive and interesting problem of the origin of life.

  15. Coordination diversity of new mononucleating hydrazone in 3d metal complexes: Synthesis, characterization and structural studies

    Directory of Open Access Journals (Sweden)

    RAJESH S. BALIGAR

    2006-12-01

    Full Text Available The mononucleating hydrazone ligand LH3, a condensation product of salicyloylhydrazine and (2-formylphenoxyacetic acid, was synthesized and its coordination behavior with first row transition metal(II ions was investigated by isolating and elucidating the structure of the complexes using elemental analysis, conductivity and magnetic susceptibility measurements, as well as IR, 1H-NMR, electronic and EPR spectral techniques. The ligand forms mononuclear metal(II complexes of the type [CoLH(H2O2], [NiLH(H2O2, [CuLH] and [ZnLH]. The ligand field parameters, Dq, B and b values, in the case of the cobalt and nickel complexes support not only the octahedral geometry around the metal ion, but also imply the covalent nature of the bonding in the complexes. The EPR study revealed the presence of a spin exchange interaction in the solid copper complex and the covalent nature of the bonding. The 1H-NMR study of the zinc(II complex indicated the non-involvement of the COOH group in the coordination. The physico-chemical study supports for the presence of octahedral geometry around cobalt(II, nickel(II and tetrahedral geometry around copper(II and zinc(II ions.

  16. Multi-Robot Coordination in Complex Environment with Task and Communication Constraints

    OpenAIRE

    Liu, Yabo; Yang, Jianhua; Zheng, Yao; Wu, Zhaohui; Yao, Min

    2013-01-01

    Abstract The tasks would fail to be assigned to any robots in the task allocation phase as a consequence of the inherent communication constraints in multi-robot systems (MRS). This negative effect becomes even more serious in tasks with temporal constraints. We therefore propose the constraint-based approach (CoBA), a market-based task allocation approach to enable multi-robot coordination in domains with temporal constraints between subtasks of a complex task and network constraints between...

  17. Complex Systems Biology Approach To Understanding Coordination of JAK-STAT Signaling

    OpenAIRE

    Soebiyanto, Radina P.; Sreenath, Sree N.; Qu, Cheng-Kui; Loparo, Kenneth A.; Bunting, Kevin D.

    2007-01-01

    In this work, we search for coordination as an organizing principle in a complex signaling system using a multilevel hierarchical paradigm. The objective is to explain the underlying mechanism of Interferon (IFNγ) induced JAK-STAT (specifically JAK1/JAK2-STAT1) pathway behavior. Starting with a mathematical model of the pathway from the literature, we modularize the system using biological knowledge via principles of biochemical cohesion, biological significance, and functionality. The modula...

  18. The DREAM complex: master coordinator of cell cycle-dependent gene expression.

    Science.gov (United States)

    Sadasivam, Subhashini; DeCaprio, James A

    2013-08-01

    The dimerization partner, RB-like, E2F and multi-vulval class B (DREAM) complex provides a previously unsuspected unifying role in the cell cycle by directly linking p130, p107, E2F, BMYB and forkhead box protein M1. DREAM mediates gene repression during the G0 phase and coordinates periodic gene expression with peaks during the G1/S and G2/M phases. Perturbations in DREAM complex regulation shift the balance from quiescence towards proliferation and contribute to the increased mitotic gene expression levels that are frequently observed in cancers with a poor prognosis.

  19. MICOS coordinates with respiratory complexes and lipids to establish mitochondrial inner membrane architecture.

    Science.gov (United States)

    Friedman, Jonathan R; Mourier, Arnaud; Yamada, Justin; McCaffery, J Michael; Nunnari, Jodi

    2015-04-28

    The conserved MICOS complex functions as a primary determinant of mitochondrial inner membrane structure. We address the organization and functional roles of MICOS and identify two independent MICOS subcomplexes: Mic27/Mic10/Mic12, whose assembly is dependent on respiratory complexes and the mitochondrial lipid cardiolipin, and Mic60/Mic19, which assembles independent of these factors. Our data suggest that MICOS subcomplexes independently localize to cristae junctions and are connected via Mic19, which functions to regulate subcomplex distribution, and thus, potentially also cristae junction copy number. MICOS subunits have non-redundant functions as the absence of both MICOS subcomplexes results in more severe morphological and respiratory growth defects than deletion of single MICOS subunits or subcomplexes. Mitochondrial defects resulting from MICOS loss are caused by misdistribution of respiratory complexes in the inner membrane. Together, our data are consistent with a model where MICOS, mitochondrial lipids and respiratory complexes coordinately build a functional and correctly shaped mitochondrial inner membrane.

  20. Coordination chemistry and reactivity of zinc complexes supported by a phosphido pincer ligand.

    Science.gov (United States)

    D'Auria, Ilaria; Lamberti, Marina; Mazzeo, Mina; Milione, Stefano; Roviello, Giuseppina; Pellecchia, Claudio

    2012-02-20

    The preparation and characterization of new Zn(II) complexes of the type [(PPP)ZnR] in which R = Et (1) or N(SiMe(3))(2) (2) and PPP is a tridentate monoanionic phosphido ligand (PPP-H = bis(2-diphenylphosphinophenyl)phosphine) are reported. Reaction of ZnEt(2) and Zn[N(SiMe(3))(2)](2) with one equivalent of proligand PPP-H produced the corresponding tetrahedral zinc ethyl (1) and zinc amido (2) complexes in high yield. Homoleptic (PPP)(2) Zn complex 3 was obtained by reaction of the precursors with two equivalents of the proligand. Structural characterization of 1-3 was achieved by multinuclear NMR spectroscopy ((1)H, (13)C, and (31)P) and X-ray crystallography (3). Variable-temperature (1)H and (31)P NMR studies highlighted marked flexibility of the phosphido pincer ligand in coordination at the metal center. A DFT calculation on the compounds provided theoretical support for this behavior. The activities of 1 and 2 toward the ring-opening polymerization of ε-caprolactone and of L- and rac-lactide were investigated, also in combination with an alcohol as external chain-transfer agent. Polyesters with controlled molecular parameters (M(n), end groups) and low polydispersities were obtained. A DFT study on ring-opening polymerization promoted by these complexes highlighted the importance of the coordinative flexibility of the ancillary ligand to promote monomer coordination at the reactive zinc center. Preliminary investigations showed the ability of these complexes to promote copolymerization of L-lactide and ε-caprolactone to achieve random copolymers whose microstructure reproduces the composition of the monomer feed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    International Nuclear Information System (INIS)

    Kosog, Boris

    2012-01-01

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

  2. Copper-based metal coordination complexes with Voriconazole ligand: Syntheses, structures and antimicrobial properties

    Science.gov (United States)

    Zhao, Yan-Ming; Tang, Gui-Mei; Wang, Yong-Tao; Cui, Yue-Zhi; Ng, Seik Weng

    2018-03-01

    Three new chiral metal coordination complexes, namely, [Cu(FZ)2(CH3COO)2(H2O)]·2H2O (1), [Cu(FZ)2(NO3)2] (2), and [Cu2(FZ)2 (H2O)8](SO4)2·4H2O (3) [FZ = (2R,3S)-2-(2,4-difluorophenyl)-3-(5-fluoro-4-pyrimidiny)-1-(1H-1,2,4-triazol-1-yl)-2-butanol) (Voriconazole)] have been obtained by the reaction of Cu(II) salts and the free ligand FZ at room temperature. Complexes 1-3 were structurally characterized by X-ray single-crystal diffraction, IR, UV-vis, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complex 1 crystallizes in the chiral space group C2, which exhibits a mono-nuclear structure. Both complexes 2 and 3 display a one-dimensional (1D) tape structure, which crystallize in chiral space group P21212 and P212121, respectively. Among these complexes, there exist a variety of hydrogen bonds and stacking interactions, through which a three-dimensional supramolecular architecture will be generated. Compared with the standard (Voriconazole), these Cu-based complexes show the more potent inhibiting efficiency against the species of Candida and Aspergillus. Moreover, among these complexes, complex 1 shows the most excellent efficiency.

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

    Directory of Open Access Journals (Sweden)

    Eon S. Burkett

    2014-12-01

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

  4. Heterobimetallic coordination polymers involving 3d metal complexes and heavier transition metals cyanometallates

    Energy Technology Data Exchange (ETDEWEB)

    Peresypkina, Eugenia V. [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Samsonenko, Denis G. [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Vostrikova, Kira E., E-mail: vosk@niic.nsc.ru [Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); LMI, Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France)

    2015-04-15

    The results of the first steps in the design of coordination polymers based on penta- and heptacyanometallates of heavier d transitions metals are presented. The 2D structure of the coordination polymers: [(Mn(acacen)){sub 2}Ru(NO)(CN){sub 5}]{sub n} and two complexes composed of different cyanorhenates, [Ni(cyclam)]{sub 2}[ReO(OH)(CN){sub 4}](ClO{sub 4}){sub 2}(H{sub 2}O){sub 1.25} and [Cu(cyclam)]{sub 2}[Re(CN){sub 7}](H{sub 2}O){sub 12}, was confirmed by single crystal XRD study, the rhenium oxidation state having been proved by the magnetic measurements. An amorphism of [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2} (M=Ni, Cu) polymers does not allow to define strictly their dimensionality and to model anisotropic magnetic behavior of the compounds. However, with high probability a honey-comb like layer structure could be expected for [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2} complexes, studied in this work, because such an arrangement is the most common among the bimetallic assemblies of hexa- and octacyanometallates with a ratio [M(cyclam)]/[M(CN){sub n}]=3/2. For the first time was prepared and fully characterized a precursor (n-Bu{sub 4}N){sub 2}[Ru(NO)(CN){sub 5}], soluble in organic media. - Graphical abstract: The very first results in the design of 2D coordination polymers based on penta- and heptacyanometallates of 4d and5d transitions metals are presented. - Highlights: • Design of coordination polymers based on penta- and heptacyanometallates. • New Ru and Re cyanide based heterobimetallic coordination complexes. • Hydrolysis and ox/red processes involving [Re(CN){sub 7}]{sup 3+} during crystallization. • High magnetic anisotropy of [M(cyclam)]{sub 3}[Re(CN){sub 7}]{sub 2}(H{sub 2}O){sub n}, M=Cu, Ni, complexes.

  5. Correlation of Solid State and Solution Coordination Numbers with Infrared Spectroscopy in Five-, Six-, and Eight-Coordinate Transition Metal Complexes of DOTAM.

    Science.gov (United States)

    Nagata, Maika K C T; Brauchle, Paul S; Wang, Sen; Briggs, Sarah K; Hong, Young Soo; Laorenza, Daniel W; Lee, Andrea G; Westmoreland, T David

    2016-08-16

    Three new DOTAM (1,4,7,10-tetrakis(acetamido)-1,4,7,10-tetraazacyclododecane) complexes have been synthesized and characterized by X-ray crystallography: [Co(DOTAM)]Cl 2 •3H 2 O, [Ni(DOTAM)]Cl 2 •4H 2 O, and [Cu(DOTAM)](ClO 4 ) 2 •H 2 O. Solid state and solution IR spectroscopic features for a series of [M(DOTAM)] 2+ complexes (M=Mn, Co, Cu, Ni, Ca, Zn) correlate with solid state and solution coordination numbers. [Co(DOTAM)] 2+ , [Ni(DOTAM)] 2+ , and [Zn(DOTAM)] 2+ are demonstrated to be six-coordinate in both the solid state and in solution, while [Mn(DOTAM)] 2+ and [Ca(DOTAM)] 2+ are eight-coordinate in the solid state and remain so in solution. [Cu(DOTAM)] 2+ , which is five-coordinate by X-ray crystallography, is shown to increase its coordination number in solution to six-coordinate.

  6. Anticancer Activity and Modes of Action of (arene) ruthenium(II) Complexes Coordinated to C-, N-, and O-ligands.

    Science.gov (United States)

    Biersack, Bernhard

    2016-01-01

    An overview of anticancer active (arene)ruthenium(II) complexes coordinated to period 2 element-based ligand systems, i.e., carbon-, nitrogen-, and oxygen-coordinated ligands, is provided in this mini-review. A bridge is forged from the large group of anticancer active ruthenium compounds with monodentate and chelating nitrogen ligands via complexes of O,O-chelating ligands to organometallic ruthenium derivatives coordinated to carbon. (Arene)ruthenium(II) complexes with reduced side-effects and enhanced efficacy against cancer are highlighted. Pertinent literature is covered up to 2014.

  7. 1H resonances of proximal histidine in CO complexes of hemoglobins provide a sensitive probe of coordination geometry

    International Nuclear Information System (INIS)

    Dalvit, C.; Tennant, L.; Wright, P.E.

    1987-01-01

    A straightforward strategy for assignment of the C ε H, C δ H, N δ H proton resonances of the proximal histidine ligand in diamagnetic complexes of monomeric hemoglobins and myoglobins is reported. These resonances are subject to large ring current shifts and are highly sensitive to coordination geometry. There are no significant differences between the CO complexes of myoglobin, leghemoglobin or hemoglobin α-subunits in proximal His coordination geometry or hydrogen bonding to the backbone at Leu F4. Ring current calculations show that the His F8 coordination geometry in the CO complexes of myoglobin and hemoglobin α-subunits is very similar in crystal and solution. (Auth.)

  8. Hardware Implementation of a Modified Delay-Coordinate Mapping-Based QRS Complex Detection Algorithm

    Directory of Open Access Journals (Sweden)

    Andrej Zemva

    2007-01-01

    Full Text Available We present a modified delay-coordinate mapping-based QRS complex detection algorithm, suitable for hardware implementation. In the original algorithm, the phase-space portrait of an electrocardiogram signal is reconstructed in a two-dimensional plane using the method of delays. Geometrical properties of the obtained phase-space portrait are exploited for QRS complex detection. In our solution, a bandpass filter is used for ECG signal prefiltering and an improved method for detection threshold-level calculation is utilized. We developed the algorithm on the MIT-BIH Arrhythmia Database (sensitivity of 99.82% and positive predictivity of 99.82% and tested it on the long-term ST database (sensitivity of 99.72% and positive predictivity of 99.37%. Our algorithm outperforms several well-known QRS complex detection algorithms, including the original algorithm.

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

    OpenAIRE

    Kosog, Boris

    2012-01-01

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

  10. Ligand design for site-selective metal coordination: synthesis of transition-metal complexes with η{sup 6}-coordination of the central ring of anthracene

    Energy Technology Data Exchange (ETDEWEB)

    Karslyan, Eduard E.; Borissova, Alexandra O.; Perekalin, Dmitry S. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation)

    2017-05-08

    A polycyclic aromatic ligand for site-selective metal coordination was designed by using DFT calculations. The computational prediction was confirmed by experiments: 2,3,6,7-tetramethoxy-9,10-dimethylanthracene initially reacts with [(C{sub 5}H{sub 5})Ru(MeCN){sub 3}]BF{sub 4} to give the kinetic product with a [(C{sub 5}H{sub 5})Ru]{sup +} fragment coordinated at the terminal ring, which is then transformed into the thermodynamic product with coordination through the central ring. These isomeric complexes have markedly different UV/Vis spectra, which was explained by analysis of the frontier orbitals. At the same time, the calculations suggest that electrostatic interactions are mainly responsible for the site selectivity of the coordination. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Functional cooperation between FACT and MCM is coordinated with cell cycle and differential complex formation

    Directory of Open Access Journals (Sweden)

    Lin Chih-Li

    2010-02-01

    Full Text Available Abstract Background Functional cooperation between FACT and the MCM helicase complex constitutes an integral step during DNA replication initiation. However, mode of regulation that underlies the proper functional interaction of FACT and MCM is poorly understood. Methods & Results Here we present evidence indicating that such interaction is coordinated with cell cycle progression and differential complex formation. We first demonstrate the existence of two distinct FACT-MCM subassemblies, FACT-MCM2/4/6/7 and FACT-MCM2/3/4/5. Both complexes possess DNA unwinding activity and are subject to cell cycle-dependent enzymatic regulation. Interestingly, analysis of functional attributes further suggests that they act at distinct, and possibly sequential, steps during origin establishment and replication initiation. Moreover, we show that the phosphorylation profile of the FACT-associated MCM4 undergoes a cell cycle-dependent change, which is directly correlated with the catalytic activity of the FACT-MCM helicase complexes. Finally, at the quaternary structure level, physical interaction between FACT and MCM complexes is generally dependent on persistent cell cycle and further stabilized upon S phase entry. Cessation of mitotic cycle destabilizes the complex formation and likely leads to compromised coordination and activities. Conclusions Together, our results correlate FACT-MCM functionally and temporally with S phase and DNA replication. They further demonstrate that enzymatic activities intrinsically important for DNA replication are tightly controlled at various levels, thereby ensuring proper progression of, as well as exit from, the cell cycle and ultimately euploid gene balance.

  12. Hydrothermal synthesis and characterization of a binuclear complex and a coordination

    Directory of Open Access Journals (Sweden)

    Reza Mohamadinasab

    2010-06-01

    Full Text Available Two new copper complexes [(bipy(pydcCu(μ-OCO-pydcCu(bipy(H2O].3.5H¬2O (1 and {[(μ2-C2O4(2,2'-bipyCu].2H2O}n (2 (pydcH2 = pyridine-2,6-dicarboxylilic acid, bipy = 2,2'-bipyridine have been hydrothermally synthesized. Both complexes were characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction studies. Complex 1 consists of two independent neutral molecules. In every moiety, metal ion center is in a distorted octahedral geometry. Coordination polymer (2 has been prepared from the reaction of bis-(cyclohexanone-oxal-dihydrazone,2,2'-bipyridine and Cu(NO32 in basic solution and under hydrothermal condition. The results showed that the bis-(cyclohexanone-oxal-dihydrazone was converted to oxalate ion under heating and basic pH. Each metal ion center in 2 is in a distorted octahedral geometry and is coordinated by four oxygen atoms of two bridged oxalate ions and two nitrogen atoms of 2,2'-bipyridine molecules. In the crystal structure of 2, some H-bonds and π-π interaction cause formation of a 3D network.

  13. An interesting coordination complex formed between the azo dye Sudan Red G and cobalt ion

    Science.gov (United States)

    Garcia, Humberto C.; Ferreira, Gilson Rodrigues; de Oliveira, Luiz Fernando C.

    2014-03-01

    In this study, the synthesis, spectroscopic analysis (Raman and infrared) and crystal structure of compound denominated [Co(SRG)2]·CH3CH2OH have been investigated, were SRG is 1-(2-methoxyphenyl-azo)-2-naphthol or simply Sudan Red G and CH3CH2OH is one molecule of ethanol. The repeating unit is formed by the presence of an adduct complex constituted by two SRG ligands coordinated to the cobalt ion in a slightly distorted octahedral geometry. The other building block consists of a molecule of ethanol, which was used as the reaction solvent. The spectroscopic analysis provided important information related to coordination and formation of molecular complex through its mains bands. In the Raman spectrum the presence of marker bands as in at 1224 cm-1 ascribed to the binder SRG [δ(NH) + ν(COC) + δ(CH) + ν(CC)] were displaced in the complex formed to 1232 cm-1 due to the loss of the proton from the azo group and the formation of a bond between the oxygen of the ether group with the metal ion. In the infrared spectrum the bands at 653/489 cm-1 and 622/528 cm-1 were attributed to [ν(CoO) + νCC)] and [νCoN + νCC] characteristic of the metal-ligand bond.

  14. Talking about the institutional complexity of the integrated rehabilitation system – the importance of coordination

    Directory of Open Access Journals (Sweden)

    Sari Miettinen

    2013-03-01

    Full Text Available Rehabilitation in Finland is a good example of functions divided among several welfare sectors, such as health services and social services.  The rehabilitation system in Finland is a complex one and there have been many efforts to create a coordinated entity. The purpose of this study is to open up a complex welfare system at the upper policy level and to understand the meaning of coordination at the level of service delivery. We shed light in particular on the national rehabilitation policy in Finland and how the policy has tried to overcome the negative effects of institutional complexity. In this study we used qualitative content analysis and frame analysis. As a result we identified four different welfare state frames with distinct features of policy problems, policy alternatives and institutional failure. The rehabilitation policy in Finland seems to be divided into different components which may cause problems at the level of service delivery and thus in the integration of services. Bringing these components together could at policy level enable a shared view of the rights of different population groups, effective management of integration at the level of service delivery and also an opportunity for change throughout the rehabilitation system.

  15. Hydrogen-Bonded Homoleptic Fluoride-Diarylurea Complexes: Structure, Reactivity, and Coordinating Power.

    Science.gov (United States)

    Pfeifer, Lukas; Engle, Keary M; Pidgeon, George W; Sparkes, Hazel A; Thompson, Amber L; Brown, John M; Gouverneur, Véronique

    2016-10-04

    Hydrogen bonding with fluoride is a key interaction encountered when analyzing the mode of action of 5'-fluoro-5'-deoxyadenosine synthase, the only known enzyme capable of catalyzing the formation of a C-F bond from F - . Further understanding of the effect of hydrogen bonding on the structure and reactivity of complexed fluoride is therefore important for catalysis and numerous other applications, such as anion supramolecular chemistry. Herein we disclose a detailed study examining the structure of 18 novel urea-fluoride complexes in the solid state, by X-ray and neutron diffraction, and in solution phase and explore the reactivity of these complexes as a fluoride source in S N 2 chemistry. Experimental data show that the structure, coordination strength, and reactivity of the urea-fluoride complexes are tunable by modifying substituents on the urea receptor. Hammett analysis of aryl groups on the urea indicates that fluoride binding is dependent on σ p and σ m parameters with stronger binding being observed for electron-deficient urea ligands. For the first time, defined urea-fluoride complexes are used as fluoride-binding reagents for the nucleophilic substitution of a model alkyl bromide. The reaction is slower in comparison with known alcohol-fluoride complexes, but S N 2 is largely favored over E2, at a ratio surpassing all hydrogen-bonded complexes documented in the literature for the model alkyl bromide employed. Increased second-order rate constants at higher dilution support the hypothesis that the reactive species is a 1:1 urea-fluoride complex of type [UF] - (U = urea) resulting from partial dissociation of the parent compound [U 2 F] - . The dissociation processes can be quantified through a combination of UV and NMR assays, including DOSY and HOESY analyses that illuminate the complexation state and H-bonding in solution.

  16. Identifying and Coordinating Care for Complex Patients: Findings from the Leading Edge of Analytics and Health Information Technology.

    Science.gov (United States)

    Rudin, Robert S; Gidengil, Courtney A; Predmore, Zachary; Schneider, Eric C; Sorace, James; Hornstein, Rachel

    2017-06-01

    In the United States, a relatively small proportion of complex patients---defined as having multiple comorbidities, high risk for poor outcomes, and high cost---incur most of the nation's health care costs. Improved care coordination and management of complex patients could reduce costs while increasing quality of care. However, care coordination efforts face multiple challenges, such as segmenting populations of complex patients to better match their needs with the design of specific interventions, understanding how to reduce spending, and integrating care coordination programs into providers' care delivery processes. Innovative uses of analytics and health information technology (HIT) may address these challenges. Rudin and colleagues at RAND completed a literature review and held discussions with subject matter experts, reaching the conclusion that analytics and HIT are being used in innovative ways to coordinate care for complex patients but that the capabilities are limited, evidence of their effectiveness is lacking, and challenges are substantial, and important foundational work is still needed.

  17. Converting between the oxides of nitrogen using metal-ligand coordination complexes.

    Science.gov (United States)

    Timmons, Andrew J; Symes, Mark D

    2015-10-07

    The oxides of nitrogen (chiefly NO, NO3(-), NO2(-) and N2O) are key components of the natural nitrogen cycle and are intermediates in a range of processes of enormous biological, environmental and industrial importance. Nature has evolved numerous enzymes which handle the conversion of these oxides to/from other small nitrogen-containing species and there also exist a number of heterogeneous catalysts that can mediate similar reactions. In the chemical space between these two extremes exist metal-ligand coordination complexes that are easier to interrogate than heterogeneous systems and simpler in structure than enzymes. In this Tutorial Review, we will examine catalysts for the inter-conversions of the various nitrogen oxides that are based on such complexes, looking in particular at more recent examples that take inspiration from the natural systems.

  18. Computation of resonances by two methods involving the use of complex coordinates

    International Nuclear Information System (INIS)

    Bylicki, M.; Nicolaides, C.A.

    1993-01-01

    We have studied two different systems producing resonances, a highly excited multielectron Coulombic negative ion (the He - 2s2p 2 4 P state) and a hydrogen atom in a magnetic field, via the complex-coordinate rotation (CCR) and the state-specific complex-eigenvalue Schroedinger equation (CESE) approaches. For the He - 2s2p 2 4 P resonance, a series of large CCR calculations, up to 353 basis functions with explicit r ij dependence, were carried out to serve as benchmarks. For the magnetic-field problem, the CCR results were taken from the literature. Comparison shows that the state-specific CESE theory allows the physics of the problem to be incorporated systematically while keeping the overall size of the computation tractable regardless of the number of electrons

  19. Structural influence in the interaction of cysteine with five coordinated copper complexes: Theoretical and experimental studies

    Science.gov (United States)

    Huerta-Aguilar, Carlos Alberto; Thangarasu, Pandiyan; Mora, Jesús Gracia

    2018-04-01

    Copper complexes of N,N,N‧,N‧-tetrakis(pyridyl-2-ylmethyl)-1,2-diaminoethane (L1) and N,N,N‧,N‧-tetrakis(pyridyl-2-ylmethyl)-1,3-diaminopropane (L2) prepared were characterized completely by different analytical methods. The X-structure of the complexes shows that Cu(II) presents in trigonal bi-pyramidal (TBP) geometry, consisting with the electronic spectra where two visible bands corresponding to five coordinated structure were observed. Thus TD-DFT was used to analyze the orbital contribution to the electronic transitions for the visible bands. Furthermore, the interaction of cysteine with the complexes was spectrally studied, and the results were explained through DFT analysis, observing that the geometrical parameters and oxidation state of metal ions play a vital role in the binding of cysteine with copper ion. It appears that the TBP structure is being changed into octahedral geometry during the addition of cysteine to the complexes as two bands (from complex) is turned to a broad band in visible region, signifying the occupation of cysteine molecule at sixth position of octahedral geometry. In the molecular orbital analysis, the existence of a strong overlapping of HOMOs (from cysteine) with LUMOs of Cu ion was observed. The total energy of the systems calculated by DFT shows that cysteine binds favorably with copper (I) than that with Cu(II).

  20. Time-source of neural plasticity in complex bimanual coordinative tasks: Juggling.

    Science.gov (United States)

    Berchicci, Marika; Quinzi, Federico; Dainese, Andrea; Di Russo, Francesco

    2017-06-15

    Brain plasticity is especially stimulated by complex bimanual tasks, because, as for juggling, they require simultaneous control of multiple movements, high level of bimanual coordination, balance and sustained swapping attention to multiple objects interacting with both hands. Neuroimaging studies on jugglers showed changes in white and grey matter after juggling training, while the very few electroencephalographic (EEG) studies showed changes in the frequency domain. However, no study has focused on the fine temporal brain activations during a bimanual coordinative task in ecological settings. We aimed at understanding the neural correlates of juggling tasks comparing expert jugglers to non-jugglers. Both groups performed two juggling tasks with increasing difficulty (1-ball fountain and 2-ball shower in non-jugglers, 2- and 3-ball shower in expert jugglers), while the EEG was recorded. This design allowed to compare brain activities related to increasing task difficulty within the same group, and the two groups on the same task. The movement-related cortical potentials (MRCPs) for each task were segmented into epochs lasting 4.5s (-1.5/+3.0s). Results showed enhanced prefrontal recruitment with increasing task difficulty in both groups, even before movement onset. Comparing the groups on the same task, non-jugglers showed enhanced activation of prefrontal regions before and during the task execution, whereas jugglers showed enhanced activity in motor-related regions. The results provide a clear indication of practice-induced brain efficiency during the performance of complex bimanual coordinative skills. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Structural and spectroscopic characterization of five coordinate iron and cobalt bis(dithiolene)-trimethylphosphine complexes

    Science.gov (United States)

    Selby-Karney, Troy; Grossie, David A.; Arumugam, Kuppuswamy; Wright, Eyglo; Chandrasekaran, P.

    2017-08-01

    Heteroleptic bis(dithiolene)-phosphine iron and cobalt complexes [Fe(adt)2(PMe3)] (1) and [Co(adt)2(PMe3)] (2) (adt = para-anisyldithiolene) have been synthesized from corresponding bis(dithiolene) dimers [M2(adt)4]2 (M = Fe, Co) by reacting with excess PMe3 in dichloromethane. Solid-state structures of 1 and 2 have been determined by single crystal X-ray crystallography, and the dithiolene ligands Csbnd S (≈1.72 Å) and Csbnd C (≈1.37 Å) bond distances reveal the coordination of π-radical monoanionic dithiolene (adt•1-) ligands to metal centers. Intense low energy ligand-to-ligand-charge transfer (LLCT) absorption band (743 nm for 1; 905 nm for 2) in UV-vis spectra and characteristic ν(Cdbnd S•) (1168 cm-1 for 1; 1170 cm-1 for 2) in IR spectra affirms coordination of π-radical monoanionic dithiolenes to divalent metal ions. The cyclic voltammogram of 1 and 2 shows reversible oxidation and reduction waves attributed to MII → MIII + e- (+0.52 V for 1; +0.29 V for 2) and adt•1- + e- → adt2- (-0.63 V for 1; -0.46 V for 2) redox process respectively. Comprehensive structural and spectroscopic investigations conclude, [M2III(adt2-)2(adt•1-)2] → 2 [MII(adt•1-)2(PMe3)] intramolecular redox interplay during phosphine coordination induced cleavage of homoleptic bis(dithiolene) dimers to produce square pyramidal complexes.

  2. Blue Phosphorescent Zwitterionic Iridium(III) Complexes Featuring Weakly Coordinating nido-Carborane-Based Ligands.

    Science.gov (United States)

    Axtell, Jonathan C; Kirlikovali, Kent O; Djurovich, Peter I; Jung, Dahee; Nguyen, Vinh T; Munekiyo, Brian; Royappa, A Timothy; Rheingold, Arnold L; Spokoyny, Alexander M

    2016-12-07

    We report the development of a new class of phosphorescent zwitterionic bis(heteroleptic) Ir(III) compounds containing pyridyl ligands with weakly coordinating nido-carboranyl substituents. Treatment of phenylpyridine-based Ir(III) precursors with C-substituted ortho-carboranylpyridines in 2-ethoxyethanol results in a facile carborane deboronation and the formation of robust and highly luminescent metal complexes. The resulting nido-carboranyl fragments associate with the cationic Ir(III) center through primarily electrostatic interactions. These compounds phosphoresce at blue wavelengths (450-470 nm) both in a poly(methyl methacrylate) (PMMA) matrix and in solution at 77 K. These complexes display structural stability at temperatures beyond 300 °C and quantum yields greater than 40%. Importantly, the observed quantum yields correspond to a dramatic 10-fold enhancement over the previously reported Ir(III) congeners featuring carboranyl-containing ligands in which the boron cluster is covalently attached to the metal. Ultimately, this work suggests that the use of a ligand framework containing a weakly coordinating anionic component can provide a new avenue for designing efficient Ir(III)-based phosphorescent emitters.

  3. Integrated complex care coordination for children with medical complexity: A mixed-methods evaluation of tertiary care-community collaboration

    Directory of Open Access Journals (Sweden)

    Cohen Eyal

    2012-10-01

    Full Text Available Abstract Background Primary care medical homes may improve health outcomes for children with special healthcare needs (CSHCN, by improving care coordination. However, community-based primary care practices may be challenged to deliver comprehensive care coordination to complex subsets of CSHCN such as children with medical complexity (CMC. Linking a tertiary care center with the community may achieve cost effective and high quality care for CMC. The objective of this study was to evaluate the outcomes of community-based complex care clinics integrated with a tertiary care center. Methods A before- and after-intervention study design with mixed (quantitative/qualitative methods was utilized. Clinics at two community hospitals distant from tertiary care were staffed by local community pediatricians with the tertiary care center nurse practitioner and linked with primary care providers. Eighty-one children with underlying chronic conditions, fragility, requirement for high intensity care and/or technology assistance, and involvement of multiple providers participated. Main outcome measures included health care utilization and expenditures, parent reports of parent- and child-quality of life [QOL (SF-36®, CPCHILD©, PedsQL™], and family-centered care (MPOC-20®. Comparisons were made in equal (up to 1 year pre- and post-periods supplemented by qualitative perspectives of families and pediatricians. Results Total health care system costs decreased from median (IQR $244 (981 per patient per month (PPPM pre-enrolment to $131 (355 PPPM post-enrolment (p=.007, driven primarily by fewer inpatient days in the tertiary care center (p=.006. Parents reported decreased out of pocket expenses (p© domains [Health Standardization Section (p=.04; Comfort and Emotions (p=.03], while total CPCHILD© score decreased between baseline and 1 year (p=.003. Parents and providers reported the ability to receive care close to home as a key benefit. Conclusions Complex

  4. Synthesis and characterization of phosphorescent two-coordinate copper(i) complexes bearing diamidocarbene ligands.

    Science.gov (United States)

    Shi, Shuyang; Collins, Lee R; Mahon, Mary F; Djurovich, Peter I; Thompson, Mark E; Whittlesey, Michael K

    2017-01-17

    The photophysical properties of four, two-coordinate, linear diamidocarbene copper(i) complexes, [(DAC) 2 Cu][BF 4 ] (1), (DAC)CuOSiPh 3 (2), (DAC)CuC 6 F 5 (3) and (DAC)Cu(2,4,6-Me 3 C 6 H 2 ) (4) (DAC = 1,3-bis(2,4,6-trimethylphenyl)-5,5-dimethyl-4,6-diketopyrimidinyl-2-ylidene) have been investigated. Complex 1 shows a high photoluminescence quantum efficiency (Φ PL ) in both the solid state (Φ PL = 0.85) and in CH 2 Cl 2 solution (Φ PL = 0.65). The emission band of 1, both as a crystalline solid and in solution, is narrow (fwhm = 2300 cm -1 ) relative to the emission bands of 2 (fwhm = 2900 cm -1 ) and 3 (fwhm = 3700 cm -1 ). Complexes 2 and 3 are each brightly luminescent in the solid state (Φ PL = 0.62 and 0.18, respectively), but markedly less so in CH 2 Cl 2 solution (Φ PL = 0.03 and <0.01, respectively). Complex 4 is not emissive in either the solid state or in solution. Phosphorescence of 1 in CH 2 Cl 2 solution shows negligible quenching by oxygen in CH 2 Cl 2 solution. This insensitivity to quenching is attributed to the excited state redox potential being insufficient for electron transfer to oxygen.

  5. Catalytic effect in opening the coordination sphere of an organo-f-complex

    International Nuclear Information System (INIS)

    Andrea, T.; Wang, J.; Gourevich, I.; Eisen, M.S.

    2002-01-01

    Organo-f-complexes have been studied in the last decade showing unique stoichiometric and catalytic properties, which are deeply influenced by the nature of the x ancillary ligands. Opening of the metal center coordination sphere is obtained by replacing the pentamethylcyclopentadienyl ligation in Cp* 2 MR 2 (Cp* = C 5 Me 5 , M = f-element metal, R = a-bonded ligand) by the bridged ancillary ligation Anna-Me 2 SiCp 2MR 2 (Cp* = C 5 Me 4 ). For organolanthanides, this change allows an increase (10-100 fold) in rates for the olefin insertion into the M-R bond [1] and in organoactinides; this modification has been shown to cause an increase (103 fold) in their catalytic activity for the hydrogenation of 1-hexene [2]. Recently, we have shown that organoactinides of the type Cp* 2 MR 2 (Cp* = C 5 Me 5 ; M = Th, U; R = CH 3 ) are active catalysts for both the oligomerization and hydrosilylation of terminal alkynes [3J. Thus, a conceptual question arises regarding the use of an open organoactinide such as Me 2 SiCp* 2 U n Bu 2 as compared to Cp* 2 UR 2 . This opening in the coordination sphere at the metal center should be unique in such a way that it is reasonable expected the increase of the reactivity towards product formation in the hydrosilylation and metathesis catalytic processes of terminal alkynes. In this poster we report, and quantitatively compare, the effects of the ansa-organouranium complex (Me 2 SiCp'' 2 U n Bu) 2 O The synthesis of the complex was achieved as described in equations 1 and 2

  6. Lanthanide Chemistry: From Coordination in Chemical Complexes Shaping Our Technology to Coordination in Enzymes Shaping Bacterial Metabolism.

    Science.gov (United States)

    Martinez-Gomez, Norma Cecilia; Vu, Huong N; Skovran, Elizabeth

    2016-10-17

    Lanthanide chemistry has only been extensively studied for the last 2 decades, when it was recognized that these elements have unusual chemical characteristics including fluorescent and potent magnetic properties because of their unique 4f electrons.1,2 Chemists are rapidly and efficiently integrating lanthanides into numerous compounds and materials for sophisticated applications. In fact, lanthanides are often referred to as "the seeds of technology" because they are essential for many technological devices including smartphones, computers, solar cells, batteries, wind turbines, lasers, and optical glasses.3-6 However, the effect of lanthanides on biological systems has been understudied. Although displacement of Ca 2+ by lanthanides in tissues and enzymes has long been observed,7 only a few recent studies suggest a biological role for lanthanides based on their stimulatory properties toward some plants and bacteria.8,9 Also, it was not until 2011 that the first biochemical evidence for lanthanides as inherent metals in bacterial enzymes was published.10 This forum provides an overview of the classical and current aspects of lanthanide coordination chemistry employed in the development of technology along with the biological role of lanthanides in alcohol oxidation. The construction of lanthanide-organic frameworks will be described. Examples of how the luminescence field is rapidly evolving as more information about lanthanide-metal emissions is obtained will be highlighted, including biological imaging and telecommunications.11 Recent breakthroughs and observations from different exciting areas linked to the coordination chemistry of lanthanides that will be mentioned in this forum include the synthesis of (i) macrocyclic ligands, (ii) antenna molecules, (iii) coordination polymers, particularly nanoparticles, (iv) hybrid materials, and (v) lanthanide fuel cells. Further, the role of lanthanides in bacterial metabolism will be discussed, highlighting the

  7. Low-Complexity Interference-Free Downlink Channel Assignment with Improved Performance in Coordinated Small Cells

    KAUST Repository

    Radaydeh, Redha M.

    2015-05-01

    This paper proposes a low-complexity interference-free channel assignment scheme with improved desired downlink performance in coordinated multi-antenna small-coverage access points (APs) that employ the open-access control strategy. The adopted system treats the case when each user can be granted an access to one of the available channels at a time. Moreover, each receive terminal can suppress a limited number of resolvable interfering sources via its highly-correlated receive array. On the other hand, the operation of the deployed APs can be coordinated to serve active users, and the availability of multiple physical channels and the use of uncorrelated transmit antennas at each AP are exploited to improve the performance of supported users. The analysis provides new approaches to use the transmit antenna array at each AP, the multiple physical channels, the receive antenna array at each user in order to identify interference-free channels per each user, and then to select a downlink channel that provides the best possible improved performance. The event of concurrent interference-free channel identification by different users is also treated to further improve the desired link associated with the scheduled user. The analysis considers the practical scenario of imperfect identification of interference-free channel by an active user and/or the imperfectness in scheduling concurrent users requests on the same channel. The developed formulations can be used to study any performance metric and they are applicable for any statistical and geometric channel models. © 2015 IEEE.

  8. Insights into copper coordination in the EcoRI-DNA complex by ESR spectroscopy

    Science.gov (United States)

    Ji, Ming; Tan, Likun; Jen-Jacobson, Linda; Saxena, Sunil

    2014-12-01

    The EcoRI restriction endonuclease requires one divalent metal ion in each of two symmetrical and identical catalytic sites to catalyse double-strand DNA cleavage. Recently, we showed that Cu2+ binds outside the catalytic sites to a pair of new sites at H114 in each sub-unit, and inhibits Mg2+-catalysed DNA cleavage. In order to provide more detailed structural information on this new metal ion binding site, we performed W-band (∼94 GHz) and X-band (∼9.5 GHz) electron spin resonance spectroscopic measurements on the EcoRI-DNA-(Cu2+)2 complex. Cu2+ binding results in two distinct components with different gzz and Azz values. X-band electron spin echo envelope modulation results indicate that both components arise from a Cu2+ coordinated to histidine. This observation is further confirmed by the hyperfine sub-level correlation results. W-band electron nuclear double resonance spectra provide evidence for equatorial coordination of water molecules to the Cu2+ ions.

  9. Factors governing the metal coordination number in metal complexes from Cambridge Structural Database analyses.

    Science.gov (United States)

    Dudev, Minko; Wang, Jonathan; Dudev, Todor; Lim, Carmay

    2006-02-02

    The metal coordination number (CN) is a key determinant of the structure and properties of metal complexes. It also plays an important role in metal selectivity in certain metalloproteins. Despite its central role, the preferred CN for several metal cations remains ambiguous, and the factors determining the metal CN are not fully understood. Here, we evaluate how the CN depends on (1) the metal's size, charge, and charge-accepting ability for a given set of ligands, and (2) the ligand's size, charge, charge-donating ability, and denticity for a given metal by analyzing the Cambridge Structural Database (CSD) structures of metal ions in the periodic table. The results show that for a given ligand type, the metal's size seems to affect its CN more than its charge, especially if the ligand is neutral, whereas, for a given metal type, the ligand's charge and charge-donating ability appear to affect the metal CN more than the ligand's size. Interestingly, all 98 metal cations surveyed could adopt more than than one CN, and most of them show an apparent preference toward even rather than odd CNs. Furthermore, as compared to the preferred metal CNs observed in the CSD, those in protein binding sites generally remain the same. This implies that the protein matrix (excluding amino acid residues in the metal's first and second coordination shell) does not impose severe geometrical restrictions on the bound metal cation.

  10. Syntheses and Characterization of Ruthenium(II) Tetrakis(pyridine)complexes: An Advanced Coordination Chemistry Experiment or Mini-Project

    Science.gov (United States)

    Coe, Benjamin J.

    2004-01-01

    An experiment for third-year undergraduate a student is designed which provides synthetic experience and qualitative interpretation of the spectroscopic properties of the ruthenium complexes. It involves the syntheses and characterization of several coordination complexes of ruthenium, the element found directly beneath iron in the middle of the…

  11. Coordination Complexes as Catalysts: The Oxidation of Anthracene by Hydrogen Peroxide in the Presence of VO(acac)[subscript 2

    Science.gov (United States)

    Charleton, Kimberly D. M.; Prokopchuk, Ernest M.

    2011-01-01

    A laboratory experiment aimed at students who are studying coordination chemistry of transition-metal complexes is described. A simple vanadyl acetylacetonate complex can be used as a catalyst in the hydrogen peroxide oxidation of anthracene to produce anthraquinone. The reaction can be performed under a variety of reaction conditions, ideally by…

  12. Low-Complexity Scheduling and Power Adaptation for Coordinated Cloud-Radio Access Networks

    KAUST Repository

    Douik, Ahmed

    2017-07-17

    In practical wireless systems, the successful implementation of resource allocation techniques strongly depends on the algorithmic complexity. Consider a cloud-radio access network (CRAN), where the central cloud is responsible for scheduling devices to the frames’ radio resources blocks (RRBs) of the single-antenna base-stations (BSs), adjusting the transmit power levels, and for synchronizing the transmit frames across the connected BSs. Previous studies show that the jointly coordinated scheduling and power control problem in the considered CRAN can be solved using an approach that scales exponentially with the number of BSs, devices, and RRBs, which makes the practical implementation infeasible for reasonably sized networks. This paper instead proposes a low-complexity solution to the problem, under the constraints that each device cannot be served by more than one BS but can be served by multiple RRBs within each BS frame, and under the practical assumption that the channel is constant during the duration of each frame. The paper utilizes graph-theoretical based techniques and shows that constructing a single power control graph is sufficient to obtain the optimal solution with a complexity that is independent of the number of RRBs. Simulation results reveal the optimality of the proposed solution for slow-varying channels, and show that the solution performs near-optimal for highly correlated channels.

  13. Analytical description for the critical fixations of evolutionary coordination games on finite complex structured populations.

    Science.gov (United States)

    Zhang, Liye; Zou, Yong; Guan, Shuguang; Liu, Zonghua

    2015-04-01

    Evolutionary game theory is crucial to capturing the characteristic interaction patterns among selfish individuals. In a population of coordination games of two strategies, one of the central problems is to determine the fixation probability that the system reaches a state of networkwide of only one strategy, and the corresponding expectation times. The deterministic replicator equations predict the critical value of initial density of one strategy, which separates the two absorbing states of the system. However, numerical estimations of this separatrix show large deviations from the theory in finite populations. Here we provide a stochastic treatment of this dynamic process on complex networks of finite sizes as Markov processes, showing the evolutionary time explicitly. We describe analytically the effects of network structures on the intermediate fixations as observed in numerical simulations. Our theoretical predictions are validated by various simulations on both random and scale free networks. Therefore, our stochastic framework can be helpful in dealing with other networked game dynamics.

  14. Rheb may complex with RASSF1A to coordinate Hippo and TOR signaling.

    Science.gov (United States)

    Nelson, Nicholas; Clark, Geoffrey J

    2016-06-07

    The TOR pathway is a vital component of cellular homeostasis that controls the synthesis of proteins, nucleic acids and lipids. Its core is the TOR kinase. Activation of the TOR pathway suppresses autophagy, which plays a vital but complex role in tumorigenesis. The TOR pathway is regulated by activation of the Ras-related protein Rheb, which can bind mTOR. The Hippo pathway is a major growth control module that regulates cell growth, differentiation and apoptosis. Its core consists of an MST/LATS kinase cascade that can be activated by the RASSF1A tumor suppressor. The TOR and Hippo pathways may be coordinately regulated to promote cellular homeostasis. However, the links between the pathways remain only partially understood. We now demonstrate that in addition to mTOR regulation, Rheb also impacts the Hippo pathway by forming a complex with RASSF1A. Using stable clones of two human lung tumor cell lines (NCI-H1792 and NCI-H1299) with shRNA-mediated silencing or ectopic overexpression of RASSF1A, we show that activated Rheb stimulates the Hippo pathway, but is suppressed in its ability to stimulate the TOR pathway. Moreover, by selectively labeling autophagic vacuoles we show that RASSF1A inhibits the ability of Rheb to suppress autophagy and enhance cell growth. Thus, we identify a new connection that impacts coordination of Hippo and TOR signaling. As RASSF1A expression is frequently lost in human tumors, the RASSF1A status of a tumor may impact not just its Hippo pathway status, but also its TOR pathway status.

  15. Coordination Chemistry and f-Element Complexation by Diethylenetriamine-N,N″-bis(acetylglycine)-N,N',N″-triacetic Acid.

    Science.gov (United States)

    Heathman, Colt R; Grimes, Travis S; Zalupski, Peter R

    2016-11-07

    Potentiometric and spectroscopic techniques were used to evaluate the coordination behavior and thermodynamic features of trivalent f-element complexation by diethylenetriamine-N,N″-bis(acetylglycine)-N,N',N″-triacetic acid (DTTA-DAG) and its di(acetylglycine ethyl ester) analogue [diethylenetriamine-N,N″-bis(acetylglycine ethyl ester)-N,N',N″-triacetic acid (DTTA-DAGEE)]. Protonation constants and stability constants of trivalent lanthanide complexes (except Pm 3+ ) were determined by potentiometry. Six protonation sites and three metal-ligand complexes [ML 2- , MHL - , and MH 2 L(aq)] were quantified for DTTA-DAG. Four protonation sites and one metal-ligand complex [ML(aq)] were observed for DTTA-DAGEE, consistent with the presence of two ester groups. Absorption spectroscopy was utilized to measure the stability constants for complexation of trivalent neodymium and americium by DTTA-DAG and trivalent neodymium by DTTA-DAGEE. The coordination environment of trivalent europium in the presence of DTTA-DAG was investigated at various acidities by luminescence lifetime measurements. Decay constants indicate one water molecule in the inner coordination sphere across the 1.0 coordination by DTTA-DAG. A trans-lanthanide pattern of complex stabilities for DTTA-DAG was found to be analogous to that observed for DTPA, with a ∼10 6 reduction of the complex stability. The lessened strength of complexation, relative to DTPA, was attributed to significant reduction of the total ligand basicity for DTTA-DAG due to the electronic influence of amide functionalization. When DTTA-DAG is used as an aqueous holdback complexant in liquid-liquid distribution experiments, the preferential coordination of Am 3+ in the aqueous environment offers efficient An/Ln differentiation. The separation extends to pH 2 conditions, where the kinetics of phase transfer in such liquid-liquid systems are aided by the acid-catalyzed dissociation of a metal/aminopolycarboxylate complex.

  16. Care coordination, medical complexity, and unmet need for prescription medications among children with special health care needs.

    Science.gov (United States)

    Aboneh, Ephrem A; Chui, Michelle A

    Children with special health care needs (CSHCN) have multiple unmet health care needs including that of prescription medications. The objectives of this study were twofold: 1) to quantify and compare unmet needs for prescription medications for subgroups of CSHCN without and with medical complexity (CMC)-those who have multiple, chronic, and complex medical conditions associated with severe functional limitations and high utilization of health care resources, and 2) to describe its association with receipt of effective care coordination services and level of medical complexity. A secondary data analysis of the 2009/2010 National Survey of CSHCN, a nationally representative telephone survey of parents of CSHCN, was conducted. Logistic regression models were constructed to determine associations between unmet need for prescription medications and medical complexity and care coordination for families of CSHCN, while controlling for demographic variables such as race, insurance, education level, and household income. Analyses accounted for the complex survey design and sampling weights. CMC represented about 3% of CSHCN. CMC parents reported significantly more unmet need for prescription medications and care coordination (4%, 68%), compared to Non-CMC parents (2%, 40%). Greater unmet need for prescription medications was associated with unmet care coordination (adjusted OR 3.81; 95% CI: 2.70-5.40) and greater medical complexity (adjusted OR 2.01; 95% CI: 1.00-4.03). Traditional care coordination is primarily facilitated by nurses and nurse practitioners with little formal training in medication management. However, pharmacists are rarely part of the CSHCN care coordination model. As care delivery models for these children evolve, and given the complexity of and numerous transitions of care for these patients, pharmacists can play an integral role to improve unmet needs for prescription medications. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. X-ray Emission Spectroscopy to Study Ligand Valence Orbitals in Mn Coordination Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Smolentsev, Grigory; Soldatov, Alexander V; Messinger, Johannes; Merz, Kathrin; Weyhermuller, Thomas; Bergmann, Uwe; Pushkar, Yulia; Yano, Junko; Yachandra, Vittal K.; Glatzel, Pieter

    2009-03-02

    We discuss a spectroscopic method to determine the character of chemical bonding and for the identification of metal ligands in coordination and bioinorganic chemistry. It is based on the analysis of satellite lines in X-ray emission spectra that arise from transitions between valence orbitals and the metal ion 1s level (valence-to-core XES). The spectra, in connection with calculations based on density functional theory (DFT), provide information that is complementary to other spectroscopic techniques, in particular X-ray absorption (XANES and EXAFS). The spectral shape is sensitive to protonation of ligands and allows ligands, which differ only slightly in atomic number (e.g., C, N, O...), to be distinguished. A theoretical discussion of the main spectral features is presented in terms of molecular orbitals for a series of Mn model systems: [Mn(H2O)6]2+, [Mn(H2O)5OH]+, [Mn(H2O)5NH2]+, and [Mn(H2O)5NH3]2+. An application of the method, with comparison between theory and experiment, is presented for the solvated Mn2+ ion in water and three Mn coordination complexes, namely [LMn(acac)N3]BPh4, [LMn(B2O3Ph2)(ClO4)], and [LMn(acac)N]BPh4, where L represents 1,4,7-trimethyl-1,4,7-triazacyclononane, acac stands for the 2,4-pentanedionate anion, and B2O3Ph2 represents the 1,3-diphenyl-1,3-dibora-2-oxapropane-1,3-diolato dianion.

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

    Science.gov (United States)

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

    2016-06-01

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

  19. Inducing porosity and growing carbon nanofibers in ferroin perchlorate: An example of morphological transitions in coordination complexes

    Science.gov (United States)

    Avraham, Efrat Shawat; Fleker, Ohad; Benisvy, Laurent; Oakes, Landon; Pint, Cary L.; Nessim, Gilbert D.

    2017-09-01

    Inducing porosity in solid coordination complex crystals, which are an important class of catalysts, is critical for many applications where a high surface area is required. However, unlike metal organic frameworks (MOFs), fabrication of porous coordination crystals remains a significant challenge. Here we demonstrate a simple method to produce and modulate porosity in coordination complex crystals using ferroin perchlorate, a model system that combines a common ionic complex with a very reactive counter-ion. Using thermal chemical vapor deposition (CVD), we show that by annealing ferroin perchlorate crystals at 350 °C under a flow of ethylene, hydrogen, argon, and oxygen, we induced pores in the crystal. We demonstrate that small amounts of oxygen, which may combine with hydrogen to form water, are essential for pore formation. We also demonstrate that pore size and density can be easily controlled by varying the ethylene flow. Upon raising the annealing temperature to 500 °C, we observed a second transition in which carbon nanofibers (CNFs) grew from the porous crystal. This approach represents a simple and effective method for the synthesis of porous materials with good control over pore size and density. It also enables the synthesis of complex networks of nanostructures (in our case CNFs) by simply varying process parameters such as temperature and gas flows. This represents an important advance for the fabrication of porous coordination complex crystals.

  20. Electronic and Structural Effects of Inner Sphere Coordination of Chloride to a Homoleptic Copper(II) Diimine Complex.

    Science.gov (United States)

    Leandri, Valentina; Daniel, Quentin; Chen, Hong; Sun, Licheng; Gardner, James M; Kloo, Lars

    2018-04-02

    The reaction of CuCl 2 with 2,9-dimethyl-1,10-phenanthroline (dmp) does not lead to the formation of [Cu(dmp) 2 ](Cl) 2 but instead to [Cu(dmp) 2 Cl]Cl, a 5-coordinated complex, in which one chloride is directly coordinated to the metal center. Attempts at removing the coordinated chloride by changing the counterion by metathesis were unsuccessful and resulted only in the exchange of the noncoordinated chloride, as confirmed from a crystal structure analysis. Complex [Cu(dmp) 2 Cl]PF 6 exhibits a reversible cyclic voltammogram characterized by a significant peak splitting between the reductive and oxidative waves (0.85 and 0.60 V vs NHE, respectively), with a half-wave potential E 1/2 = 0.73 V vs NHE. When reduced electrochemically, the complex does not convert into [Cu(dmp) 2 ] + , as one may expect. Instead, [Cu(dmp) 2 ] + is isolated as a product when the reduction of [Cu(dmp) 2 Cl]PF 6 is performed with l-ascorbic acid, as confirmed by electrochemistry, NMR spectroscopy, and diffractometry. [Cu(dmp) 2 ] 2+ complexes can be synthesized starting from Cu(II) salts with weakly and noncoordinating counterions, such as perchlorate. Growth of [Cu(dmp) 2 ](ClO 4 ) 2 crystals in acetonitrile results in a 5-coordinated complex, [Cu(dmp) 2 (CH 3 CN)](ClO 4 ) 2 , in which a solvent molecule is coordinated to the metal center. However, solvent coordination is associated with a dynamic decoordination-coordination behavior upon reduction and oxidation. Hence, the cyclic voltammogram of [Cu(dmp) 2 (CH 3 CN)] 2+ is identical to the one of [Cu(dmp) 2 ] + , if the measurements are performed in acetonitrile. The current results show that halide ions in precursors to Cu(II) metal-organic coordination compound synthesis, and most likely also other multivalent coordination centers, are not readily exchanged when exposed to presumed strongly binding and chelating ligand, and thus special care needs to be taken with respect to product characterization.

  1. Carbene complexes of zirconium. Synthesis, structure, and reactivity with carbon monoxide to affort coordinated ketene

    International Nuclear Information System (INIS)

    Barger, P.T.; Santarsiero, B.D.; Armantrout, J.; Bercaw, J.E.

    1984-01-01

    Treatment of Cp 2 Zr(L)(CO) (Cp = C 5 H 5 ; L = PMe 3 , CO) with Cp* 2 ZrH 2 (Cp* = C 5 Me 5 ) affords zirconium oxycarbene complexes, Cp 2 (L)Zr double bond CHO single bond Zr(X)Cp* 2 (L = PMe 3 , X = H, I; L = CO, X = H), that represent some of the first examples of group 4 metal-to-carbon multiple bonding. The first X-ray diffraction structure determination of a zirconium carbene complex, that of Cp(PMe 3 )Zr double bond CHO single bond Zr(H)Cp* 2 .C 6 H 6 , is reported (C2/c, a = 27.318 (4) A, b = 19.895 (3) A, c = 19.932 (5) A β = 132.188 (10) 0 , Z = 8) and shows a very short Zr-C bond length of 2.117 (7) A. Treatment of Cp 2 (CO)Zr double bond CHO single bond Zr(H)Cp* 2 with CH 3 I or Cp 2 (PMe 3 )Zr double bond CHO single bond Zr(I)Cp* 2 with CO affords the zirconium substituted enediolate zirconacycle, Cp* 2 ZrOCH double bond C(Zr(I)Cp 2 )O, which has been characterized by an X-ray diffraction study (P2 1 /c, a = 15.866 (4) A, b = 10.673 (3) A, c = 20.561 (4) A, β = 105.5 (2) 0 , Z = 4). This complex most likely forms by coupling of the zirconoxycarbene and a carbonyl to give a metal-coordinated ketene intermediate that subsequently rearranges to the isolated product. An isotopic crossover experiment has demonstrated that the new carbon-carbon bond is formed in an intramolecular coupling step. The ketene intermediate can be trapped by dissolving Cp 2 (CO)Zr double bond CHO single bond Zr(H)Cp* 2 in pyridine, giving Cp 2 (py)Zr(O double bond C double bond CHOZr(I)Cp* 2 ). Treatment of the isolated ketene complex with CH 3 I in benzene gives the enediolate zirconocycle; in pyridine Cp 2 (py)Zr(O double bond C double bond CHOZr(I)Cp* 2 ) can be observed spectroscopically. 38 references, 4 figures, 5 tables

  2. Multi-Robot Coordination in Complex Environment with Task and Communication Constraints

    Directory of Open Access Journals (Sweden)

    Yabo Liu

    2013-05-01

    Full Text Available Abstract The tasks would fail to be assigned to any robots in the task allocation phase as a consequence of the inherent communication constraints in multi-robot systems (MRS. This negative effect becomes even more serious in tasks with temporal constraints. We therefore propose the constraint-based approach (CoBA, a market-based task allocation approach to enable multi-robot coordination in domains with temporal constraints between subtasks of a complex task and network constraints between robots. We handle network constraints by having each robot maintain a dynamic acquaintance network of robots that it knows about, and allowing a robot to submit a bid on behalf of another robot during a task auction (“indirect bidding”. In order to model the complex task, we introduce the AND/OR task tree with temporal constraints. An auction-clearing routine, which supports the AND/OR task tree with temporal constraints and direct/indirect task auction, is proposed to enable effective multi-robot task allocation in spite of various constraints. The solution was validated in both simulation and physical environments by a series of experiments in disaster response domains. Specifically, we study the system performance by separately varying the number of robots, the expected rate of task issuance, the communication reliability factor, the compositions of MRS, as well as the acquaintance relationship parameter, in simulation experiments. The results suggest that our solution outperforms others, that is, robots were able to complete the tasks more promptly and effectively.

  3. Crystal and molecular structures of sulfonato complexes of dioxouranium(VI) ion: role of steric effects on coordination structure

    International Nuclear Information System (INIS)

    Alcock, N.W.; Kemp, T.J.; Leciejewicz, J.

    1993-01-01

    The crystal structures of three sulfonato complexes of uranyl ion are described. All have linear UO 2 groups pentagonally coordinated by sulfonato or aquo ligands. In [(UO 2 )(H 2 O)(EtSO 3 ) 2 ] the coordination about UO 2 is provided by four O donated by two EtSO 3 - ligands and one O by water: a sulfonate group links the pentagonal bipyramids into chains propagating along the a axis. p-Toluenesulfonato and mesitylenesulfonato complexes of uranyl ion are monomeric and in each complex two O are donated by monodentate sulfonate and three O by water molecules. The tendencies for complexes with small ligands to form polymeric structures, and for those with bulky ligands to give monomeric structures, which we have observed with carboxylate ligands, seem to extend to sulfonate ligands. (orig.)

  4. HTP-1 coordinates synaptonemal complex assembly with homolog alignment during meiosis in C. elegans.

    Science.gov (United States)

    Couteau, Florence; Zetka, Monique

    2005-11-15

    During meiosis, the mechanisms responsible for homolog alignment, synapsis, and recombination are precisely coordinated to culminate in the formation of crossovers capable of directing accurate chromosome segregation. An outstanding question is how the cell ensures that the structural hallmark of meiosis, the synaptonemal complex (SC), forms only between aligned pairs of homologous chromosomes. In the present study, we find that two closely related members of the him-3 gene family in Caenorhabditis elegans function as regulators of synapsis. HTP-1 functionally couples homolog alignment to its stabilization by synapsis by preventing the association of SC components with unaligned and immature chromosome axes; in the absence of the protein, nonhomologous contacts between chromosomes are inappropriately stabilized, resulting in extensive nonhomologous synapsis and a drastic decline in chiasma formation. In the absence of both HTP-1 and HTP-2, synapsis is abrogated per se and the early association of SC components with chromosomes observed in htp-1 mutants does not occur, suggesting a function for the proteins in licensing SC assembly. Furthermore, our results suggest that early steps of recombination occur in a narrow window of opportunity in early prophase that ends with SC assembly, resulting in a mechanistic coupling of the two processes to promote crossing over.

  5. Coordinate transformation and matrix measure approach for synchronization of complex networks.

    Science.gov (United States)

    Juang, Jonq; Liang, Yu-Hao

    2009-09-01

    Global synchronization in complex networks has attracted considerable interest in various fields. There are mainly two analytical approaches for studying such time-varying networks. The first approach is Lyapunov function-based methods. For such an approach, the connected-graph-stability (CGS) method arguably gives the best results. Nevertheless, CGS is limited to the networks with cooperative couplings. The matrix measure approach (MMA) proposed by Chen, although having a wider range of applications in the network topologies than that of CGS, works for smaller numbers of nodes in most network topologies. The approach also has a limitation with networks having partial-state coupling. Other than giving yet another MMA, we introduce a new and, in some cases, optimal coordinate transformation to study such networks. Our approach fixes all the drawbacks of CGS and MMA. In addition, by merely checking the structure of the vector field of the individual oscillator, we shall be able to determine if the system is globally synchronized. In summary, our results can be applied to rather general time-varying networks with a large number of nodes.

  6. Complex coordinate rotation and relativistic Hylleraas-CI: helium isoelectronic series

    International Nuclear Information System (INIS)

    Pestka, G; Bylicki, M; Karwowski, J

    2007-01-01

    A combination of the Hylleraas-CI (Hy-CI) and complex coordinate rotation (CCR) methods has been applied to study the nuclear charge dependence of the eigenvalues of the Dirac-Coulomb (DC) Hamiltonian corresponding to the ground states of helium isoelectronic series atoms. It has been shown that the CCR, due to the separation of the localized states from the unphysical Brown-Ravenhall continuum, removes the instabilities of the bound-state eigenvalues observed in large-basis set Hy-CI results. The Hy-CI-CCR results are in very good agreement with the most accurate ones available in the literature. Surprisingly, the difference between the DC Hy-CI-CCR eigenvalues and the eigenvalues of the positive-energy projected no-pair Hamiltonian is equal, up to the numerical accuracy of the results, to (Zα) 3 /6π, i.e. to (Zα) 3 relativistic many-body perturbation theory contribution for electron-electron Coulomb interaction operator. An excellent agreement between the Hy-CI-CCR eigenvalues shifted by (Zα) 3 /6π and the no-pair ones confirms the very high accuracy achieved in both approaches. The numerical accuracy of the Hy-CI-CCR DC eigenvalues is estimated to eight significant figures

  7. Coordinated action of pectinesterase and polygalacturonate lyase complex of Clostridium multifermentans.

    Science.gov (United States)

    Sheiman, M I; Macmillan, J D; Miller, L; Chase, T

    1976-05-01

    The polygalacturonate lyase and pectinesterase activities of Clostridium multifermentans, both produced extracellularly when the organism grows on pectin or polygalacturonate, have been suggested to be associated in a single complex. Both enzymic sites act on their respective substrates by single-chain action patterns, as shown by equivalent release of terminal tritium label and total product throughout the reaction. From these results, the Km and V of the lyase, and the amount of lyase activity present, we calculate the steady-state concentration of lyase substrate expected during action of the two sites on pectin if the sites are independent. No such steady-state concentration of lyase substrate was observed. Therefore, we conclude that the two types of active site act in a coordinated manner; the polysaccharide chain passes from the esterase site to the lyase site without intermediate dissociation and rebinding. This 'molecular disassembly line' constituted by the two sites may represent a system of general significance in synthesis and degradation of biological polymers.

  8. Identification of Copper(II) Complexes in Aqueous Solution by Electron Spin Resonance: An Undergraduate Coordination Chemistry Experiment.

    Science.gov (United States)

    Micera, G.; And Others

    1984-01-01

    Background, procedures, and results are provided for an experiment which examines, through electron spin resonance spectroscopy, complex species formed by cupric and 2,6-dihydroxybenzoate ions in aqueous solutions. The experiment is illustrative of several aspects of inorganic and coordination chemistry, including the identification of species…

  9. Electronic Transitions as a Probe of Tetrahedral versus Octahedral Coordination in Nickel(II) Complexes: An Undergraduate Inorganic Chemistry Experiment.

    Science.gov (United States)

    Filgueiras, Carlos A. L.; Carazza, Fernando

    1980-01-01

    Discusses procedures, theoretical considerations, and results of an experiment involving the preparation of a tetrahedral nickel(II) complex and its transformation into an octahedral species. Suggests that fundamental aspects of coordination chemistry can be demonstrated by simple experiments performed in introductory level courses. (Author/JN)

  10. Rare Tautomers of 1-Methyluracil and 1-Methylthymine: Tuning Relative Stabilities through Coordination to Pt-II Complexes

    NARCIS (Netherlands)

    van der Wijst, Tushar; Guerra, Celia Fonseca; Swart, Marcel; Bickelhaupt, F. Matthias; Lippert, Bernhard

    2008-01-01

    We have computationally explored how the relative stabilities of 1-methyluracil (1-MeUH) tautomers can be tuned through coordination of these tautomers to PtII complexes with a particular set of ligands. This has been done using density functional theory at the BP86/TZ2P level. Thus, we have

  11. Effects of task complexity on coordination of inter-limb and within-limb forces in static bimanual manipulation.

    Science.gov (United States)

    Krishnan, Vennila; Jaric, Slobodan

    2010-10-01

    Coordination of the hand grip (G; acting normally to the grasping surface) and load forces (L; acting in parallel) in bimanual static tasks was studied. L symmetry (either the magnitude or direction) and frequency were manipulated in healthy participants (N = 14). More complex tasks (i.e., the higher frequency and/or asymmetric ones) revealed expected deterioration in both the task performance (accuracy of the prescribed L force profiles) and force coordination (G/L ratio and G-L correlation) suggesting importance of L frequency and symmetry in prehension activities. However, the same tasks revealed a more prominent deterioration of interlimb than the within-limb force coordination. This could be interpreted by two partly different and noncompeting neural control mechanisms where the coordination of interlimb forces may be based on ad-hoc and task-specific muscle coordination (often referred to as muscle synergies) while the within-limb coordination of G and L could be based on more stable and partly reflex mechanisms.

  12. Stability and Reactivity of Cyclometallated Naphthylamine Complexes in Pd-C Bond Insertion Reactions with Coordinated Alkynylphosphanes

    KAUST Repository

    Chen, Shuli

    2013-09-17

    Phenylbis(phenylethynyl)phosphane PhP(C≡CPh)2 coordinates regiospecifically to the α-methyl-chiral ortho-platinated and -palladated naphthylamine units at the positions trans to the nitrogen donors. The P→Pt coordination bond is kinetically inert, whereas the P→Pd bond is labile. Upon heating of these phosphane complexes at 70 °C, one of the C≡C bonds in the coordinated PhP(C≡CPh)2 was activated towards an intermolecular Pd-C bond insertion reaction with an external ortho-palladated naphthylamine ring. No intramolecular insertion reaction occurred. In contrast to its palladium analogue, the ortho-platinated ring is not reactive towards coordinated PhP(C≡CPh)2, although it can promote the Pd-C bond insertion reaction. However, despite the high kinetic stability of the P→Pt coordination, the organoplatinum unit is a noticeably weaker activator than its organopalladium counterpart. The chirality of the reacting ortho-metallated naphthylamine ligand exhibited high stereochemical influence on the formation of the new stereogenic phosphorus center during the course of these C-C bond-formation reactions. The coordination chemistry and the absolute stereochemistry of the dimetallic products were determined by single-crystal X-ray crystallographic analysis. The asymmetric monoinsertion of PhP(C≡CPh)2 coordinated to a cyclometallated N,N-dimethyl naphthyl/benzylamine template into the Pd-C bonds of N,N-dimethylnaphthylamine palladacycles has been demonstrated for the synthesis of a variety of new P-stereogenic homo- or heterodimetallic complexes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Inner-Sphere versus Outer-Sphere Coordination of BF4– in a NHC-Gold(I) Complex

    KAUST Repository

    Veenboer, Richard M. P.

    2017-07-20

    The role of counterions in chemistry mediated by gold complexes stretches much further than merely providing charge balance to cationic gold species. Interplay between their basicities and coordination strengths influences interactions with both the gold center and substrates in catalysis. Actual monogold(I) active species are generally believed to be monocoordinated species, formed from the abstraction or the decoordination of a second ligand from precursor complexes, but only a small amount of experimental evidence exists to underpin the existence of these transient species. The formation of a bench-stable neutral IPrCl-gold(I) tetrafluoroborate complex is reported herein. Experimental studies by X-ray diffraction analysis and NMR spectroscopy and theoretical studies by DFT calculations were conducted to determine the composition, structure, and behavior of this complex. The absence of an auxiliary ligand resulted in inner-sphere coordination of the counterion in the solid state. In solution, an equilibrium between two conformations was found with the counterion occupying inner-sphere and outer-sphere positions, respectively. Stoichiometric and catalytic reactivity studies with the tetrafluoroborate complex have been conducted. These confirmed the lability of the inner-sphere coordinating counterion that gives the IPrCl-gold(I) fragment behavior similar to that of related systems.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

  15. A Longitudinal Electromyography Study of Complex Movements in Poststroke Therapy. 2: Changes in Coordinated Muscle Activation

    Directory of Open Access Journals (Sweden)

    Negin Hesam-Shariati

    2017-07-01

    Full Text Available Fine motor control is achieved through the coordinated activation of groups of muscles, or “muscle synergies.” Muscle synergies change after stroke as a consequence of the motor deficit. We investigated the pattern and longitudinal changes in upper limb muscle synergies during therapy in a largely unconstrained movement in patients with a broad spectrum of poststroke residual voluntary motor capacity. Electromyography (EMG was recorded using wireless telemetry from 6 muscles acting on the more-affected upper body in 24 stroke patients at early and late therapy during formal Wii-based Movement Therapy (WMT sessions, and in a subset of 13 patients at 6-month follow-up. Patients were classified with low, moderate, or high motor-function. The Wii-baseball swing was analyzed using a non-negative matrix factorization (NMF algorithm to extract muscle synergies from EMG recordings based on the temporal activation of each synergy and the contribution of each muscle to a synergy. Motor-function was clinically assessed immediately pre- and post-therapy and at 6-month follow-up using the Wolf Motor Function Test, upper limb motor Fugl-Meyer Assessment, and Motor Activity Log Quality of Movement scale. Clinical assessments and game performance demonstrated improved motor-function for all patients at post-therapy (p < 0.01, and these improvements were sustained at 6-month follow-up (p > 0.05. NMF analysis revealed fewer muscle synergies (mean ± SE for patients with low motor-function (3.38 ± 0.2 than those with high motor-function (4.00 ± 0.3 at early therapy (p = 0.036 with an association trend between the number of synergies and the level of motor-function. By late therapy, there was no significant change between groups, although there was a pattern of increase for those with low motor-function over time. The variability accounted for demonstrated differences with motor-function level (p < 0.05 but not time. Cluster

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

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2018-02-01

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

  17. Application of an electronic bulletin board, as a mechanism of coordination of actions in complex systems - reference model

    Directory of Open Access Journals (Sweden)

    Katarzyna Grzybowska

    2015-06-01

    Full Text Available Background: In her previous research, the author of this publication indicates that coordination is a dependent variable which has a great driving force and is a very unstable factor. This results in the fact that all of the actions connected with coordination have an impact on other factors of cooperation as well as the integration of the enterprises in the structures of a supply chain type structure. Material and methods:  The article has been divided into two basic parts. The first part regards the reference models in complex systems (supply chain systems. They can constitute a starting point for the modelling of target processes in the built supply chain structure. The second part presents template process models (Reference Models for selected action coordination mechanisms during enterprise cooperation. The aim of the article is the presentation the model an Electronic Bulletin Board (EBB, as a mechanism of coordination of actions in complex systems. Results: The article was prepared on the basis of literature from the researched area. The material was also prepared on the basis of interviews with practitioners. They have allowed for the preparation of template process models (Reference Models for selected action coordination methods in the supply chain. Conclusions: The result of the work is a prepared model as well as its description in the use of IDEF0. The presented model is a demonstrative model. The proposed reference model makes it possible to define the parameters of a selected mechanism of coordination of actions, and forms a basis for affecting the progression of the process through an analysis of values of identified parameters. The parameterization of elements constitutes the foundation for the monitoring of the process via 1 unambiguous identification of the object of monitoring and 2 analysis of different variants of the progression of the process.

  18. Divergent Coordination Chemistry: Parallel Synthesis of [2×2] Iron(II) Grid-Complex Tauto-Conformers.

    Science.gov (United States)

    Schäfer, Bernhard; Greisch, Jean-François; Faus, Isabelle; Bodenstein, Tilmann; Šalitroš, Ivan; Fuhr, Olaf; Fink, Karin; Schünemann, Volker; Kappes, Manfred M; Ruben, Mario

    2016-08-26

    The coordination of iron(II) ions by a homoditopic ligand L with two tridentate chelates leads to the tautomerism-driven emergence of complexity, with isomeric tetramers and trimers as the coordination products. The structures of the two dominant [Fe(II) 4 L4 ](8+) complexes were determined by X-ray diffraction, and the distinctness of the products was confirmed by ion-mobility mass spectrometry. Moreover, these two isomers display contrasting magnetic properties (Fe(II) spin crossover vs. a blocked Fe(II) high-spin state). These results demonstrate how the coordination of a metal ion to a ligand that can undergo tautomerization can increase, at a higher hierarchical level, complexity, here expressed by the formation of isomeric molecular assemblies with distinct physical properties. Such results are of importance for improving our understanding of the emergence of complexity in chemistry and biology. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  19. Analysis of Heme Iron Coordination in DGCR8: The Heme-Binding Component of the Microprocessor Complex.

    Science.gov (United States)

    Girvan, Hazel M; Bradley, Justin M; Cheesman, Myles R; Kincaid, James R; Liu, Yilin; Czarnecki, Kazimierz; Fisher, Karl; Leys, David; Rigby, Stephen E J; Munro, Andrew W

    2016-09-13

    DGCR8 is the RNA-binding partner of the nuclease Drosha. Their complex (the "Microprocessor") is essential for processing of long, primary microRNAs (pri-miRNAs) in the nucleus. Binding of heme to DGCR8 is essential for pri-miRNA processing. On the basis of the split Soret ultraviolet-visible (UV-vis) spectrum of ferric DGCR8, bis-thiolate sulfur (cysteinate, Cys(-)) heme iron coordination of DGCR8 heme iron was proposed. We have characterized DGCR8 heme ligation using the Δ276 DGCR8 variant and combined electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD), electron nuclear double resonance, resonance Raman, and electronic absorption spectroscopy. These studies indicate DGCR8 bis-Cys heme iron ligation, with conversion from bis-thiolate (Cys(-)/Cys(-)) axial coordination in ferric DGCR8 to bis-thiol (CysH/CysH) coordination in ferrous DGCR8. Pri-miRNA binding does not perturb ferric DGCR8's optical spectrum, consistent with the axial ligand environment being separated from the substrate-binding site. UV-vis absorption spectra of the Fe(II) and Fe(II)-CO forms indicate discrete species exhibiting peaks with absorption coefficients substantially larger than those for ferric DGCR8 and that previously reported for a ferrous form of DGCR8. Electron-nuclear double resonance spectroscopy data exclude histidine or water as axial ligands for ferric DGCR8 and favor bis-thiolate coordination in this form. UV-vis MCD and near-infrared MCD provide data consistent with this conclusion. UV-vis MCD data for ferrous DGCR8 reveal features consistent with bis-thiol heme iron coordination, and resonance Raman data for the ferrous-CO form are consistent with a thiol ligand trans to the CO. These studies support retention of DGCR8 cysteine coordination upon reduction, a conclusion distinct from those of previous studies of a different ferrous DGCR8 isoform.

  20. Recovering Ga(III) from coordination complexes using pyridine 2,6-dicarboxylic acid chelation ion chromatography.

    Science.gov (United States)

    Staff, K; Brown, M B; Hider, R C; Kong, X L; Friden, P; Jones, S A

    2010-09-01

    Ion exchange chelation chromatography is an effective means to extract metals from coordination complexes and biological samples; however there is a lack of data to verify the nature of metal complexes that can be successfully analysed using such a procedure. The aim of this study was to assess the capability of pyridine 2,6-dicarboxylic acid (PDCA) to extract and quantify Ga(III) from a range of environments using standard liquid chromatography apparatus. The PDCA chelation method generated a single Ga(III) peak with a retention time of 2.55 +/- 0.02 min, a precision of PDCA assay extracted 96.9 +/- 1.2% of the spiked Ga(III) from porcine mucus and 100.7 +/- 2.7% from a citrate complex (stability constant 10.02), but only ca 50% from an EDTA complex (stability constant 22.01). These data suggest that PDCA chelation can be considered a suitable alternative to inductively coupled plasma mass spectrometry for Ga(III) quantification from all but the most strongly bound coordinated complexes i.e. a stability constant of <15. 2010 John Wiley & Sons, Ltd.

  1. Coordination of manganous ion at the active site of pyruvate, phosphate dikinase: the complex of oxalate with the phosphorylated enzyme

    International Nuclear Information System (INIS)

    Kofron, J.L.; Ash, D.E.; Reed, G.H.

    1988-01-01

    Electron paramagnetic resonance spectroscopy has been used to investigate the structure of the complex of manganous ion with the phosphorylated form of pyruvate, phosphate dikinase (E/sub p/) and the inhibitor oxalate. Oxalate, an analogue of the enolate of pyruvate, is competitive with respect to pyruvate in binding to the phosphorylated form of the enzyme. Superhyperfine coupling between the unpaired electrons of Mn(I) and ligands specifically labeled with 17 O has been used to identify oxygen ligands to Mn(II) in the complex with oxalate and the phosphorylated form of the enzyme. Oxalate binds at the active site as a bidentate chelate with Mn(II). An oxygen from the 3'-N-phosphohistidyl residue of the protein is in the coordination sphere of Mn(II), and at least two water molecules are also bound to Mn(II) in the complex. Oxalate also binds directly to Mn(II) in a complex with nonphosphorylated enzyme. The structure for the E/sub p/-Mn(II)-oxalate complex implies that simultaneous coordination of a phospho group and of the attacking nucleophile to the divalent cation is likely an important factor in catalysis of this phospho-transfer reaction

  2. Three-coordinate gold(I) N-heterocyclic carbene complexes: a new class of strongly luminescent derivatives.

    Science.gov (United States)

    Visbal, Renso; López-de-Luzuriaga, José M; Laguna, Antonio; Gimeno, M Concepción

    2014-01-07

    A selected group of cationic three-coordinate Au(I)-NHC complexes of the form [Au(NHC)(dppbz)]OTf have been prepared from a commercially available bidentate phosphine. All complexes have been fully characterised by NMR and mass spectroscopy. The [Au(NHC)](+) fragment shows a pronounced tendency to form linear complexes which is confirmed by the molecular structure of [Au(IPr)(dppbz)]OTf in the solid state. The complexes are brightly luminescent and present very high quantum yield values in the solid state. The assignments of the electronic transitions involved in the emissions are of a phosphorescent nature and it is proposed that the origin of the emissions is derived from the ligand (dppbz) to metal-ligand (Au-NHC) charge-transfer (LML'CT) transition.

  3. Correlated coordination and redox activity of a hemilabile noninnocent ligand in nickel complexes

    Czech Academy of Sciences Publication Activity Database

    Paretzki, A.; Bubrin, M.; Fiedler, Jan; Záliš, Stanislav; Kaim, W.

    2014-01-01

    Roč. 20, č. 18 (2014), s. 5414-5422 ISSN 0947-6539 R&D Projects: GA MŠk LD11086 Institutional support: RVO:61388955 Keywords : coordination change * hemilabile ligands * nickel Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.731, year: 2014

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

    KAUST Repository

    Assi, Hala

    2017-05-24

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

  5. Eddy-correlation measurements of benthic fluxes under complex flow conditions: Effects of coordinate transformations and averaging time scales

    DEFF Research Database (Denmark)

    Lorke, Andreas; McGinnis, Daniel F.; Maeck, Andreas

    2013-01-01

    hours of continuous eddy-correlation measurements of sediment oxygen fluxes in an impounded river, we demonstrate that rotation of measured current velocities into streamline coordinates can be a crucial and necessary step in data processing under complex flow conditions in non-flat environments......Eddy-correlation measurements of sediment oxygen uptake rates in aquatic systems are increasingly used to obtain areal-averaged fluxes with a high temporal resolution. Here we discuss the effects of coordinate rotation and averaging time scale for Reynolds decomposition on flux estimates. Using 119...... in the context of the theoretical concepts underlying eddy-correlation measurements and a set of recommendations for planning and analyses of flux measurements are derived....

  6. Dance choreography is coordinated with song repertoire in a complex avian display.

    Science.gov (United States)

    Dalziell, Anastasia H; Peters, Richard A; Cockburn, Andrew; Dorland, Alexandra D; Maisey, Alex C; Magrath, Robert D

    2013-06-17

    All human cultures have music and dance, and the two activities are so closely integrated that many languages use just one word to describe both. Recent research points to a deep cognitive connection between music and dance-like movements in humans, fueling speculation that music and dance have coevolved and prompting the need for studies of audiovisual displays in other animals. However, little is known about how nonhuman animals integrate acoustic and movement display components. One striking property of human displays is that performers coordinate dance with music by matching types of dance movements with types of music, as when dancers waltz to waltz music. Here, we show that a bird also temporally coordinates a repertoire of song types with a repertoire of dance-like movements. During displays, male superb lyrebirds (Menura novaehollandiae) sing four different song types, matching each with a unique set of movements and delivering song and dance types in a predictable sequence. Crucially, display movements are both unnecessary for the production of sound and voluntary, because males sometimes sing without dancing. Thus, the coordination of independently produced repertoires of acoustic and movement signals is not a uniquely human trait. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants.

    Science.gov (United States)

    Grimes, Travis S; Heathman, Colt R; Jansone-Popova, Santa; Ivanov, Alexander S; Roy, Santanu; Bryantsev, Vyacheslav S; Zalupski, Peter R

    2018-02-05

    The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am 3+ , Cm 3+ , and Ln 3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL (aq) complexes at the same aqueous acidity. The denticity change observed for Eu 3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL (aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am 3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am 3+ , Cm 3+ ) and trivalent lanthanide chelates (La 3+ -Lu 3+ ) are observed in liquid-liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by

  8. Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, Travis S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Heathman, Colt R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jansone-Popova, Santa [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Alexander S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Roy, Santanu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryantsev, Vyacheslav S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zalupski, Peter R. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2018-01-05

    Here, the novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N',N",N"-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N',N",N"-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and radioisotope distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA

  9. Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

    KAUST Repository

    Haslinger, Stefan

    2014-11-03

    This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

  10. Direct evidence for a coordination-insertion mechanism of ethylene oligomerization catalysed by neutral 2,6-bisiminopyridine iron monoalkyl complexes

    OpenAIRE

    Cartes, M. Ángeles; Rodríguez-Delgado, Antonio; Palma, Pilar; Sánchez, Luis J.; Cámpora, Juan; CSIC - Unidad de Recursos de Información Científica para la Investigación (URICI)

    2014-01-01

    1H NMR studies on ethylene oligomerization catalysed by the neutral monoalkyl complex [Fe(Me)(iPrBIP)] allow direct observation of alkyl iron intermediates as well as reversible ethylene coordination to the metal center, providing for the first time experimental evidence for a coordination-insertion mechanism of iron-catalysed ethylene upgrade reactions. © 2014 the Partner Organisations.

  11. Coordination chemistry of sugar-phosphate complexes with palladium(II), rhenium(V) and zinc(II)

    Energy Technology Data Exchange (ETDEWEB)

    Steinborn, Christian Martin

    2013-05-21

    As described before, some studies dealing with coordination chemistry of sugar phosphates are available but no analogous complexes of Zn{sup II} have been investigated yet. The primary goal of this work is, therefore, to fill this gap. In order to stay close to the active sites of enzymes such as class-II-aldolase, the simple metal fragment Zn{sup II}(dien) is used. NMR spectroscopy is used primarily as analytical method since it enables the investigation of both complex equilibria in solution and pH dependence of metal-binding sites. Since this approach is challenging due to the fast metal-ligand exchange and the absence of CIS values, it is necessary to improve the significance of NMR data collected from sugar-phosphate complexes with Zn{sup II}. Hence, further experiments are performed with molecules similar to sugar phosphates such as reducing and methylated sugars or polyols. Beside NMR spectroscopy, crystal-structure analysis will be used to get more detailed information about the binding pattern of the complexes. Additionally, sugar-phosphate complexes of Pd{sup II} are investigated. Further experiments are conducted, on the one hand, to synthesise more sugarphosphate complexes with ReVON2 fragments, and, on the other hand, to grow crystals confirming the theory about mixed sugar-core-phosphate chelation.

  12. Cytosine-Cytosine Base-Pair Mismatch and Chirality in Nucleotide Supramolecular Coordination Complexes.

    Science.gov (United States)

    Qiu, Qi-Ming; Zhou, Pei; Gu, Leilei; Hao, Liang; Liu, Minghua; Li, Hui

    2017-05-29

    The base-pair sequences are the foundation for the biological processes of DNA or RNA, and base-pair mismatch is very important to reveal genetic diseases and DNA rearrangements. However, the lack of well-defined structural information about base-pair mismatch is obstructing the investigation of this issue. The challenge is to crystallize the materials containing the base-pair mismatch. Engineering the small-molecule mimics or model is an effective strategy to solve this issue. Here, six cytidine-5'-monophosphate (CMP) and 2'-deoxycytidine-5'-monophosphate (dCMP) coordination polymers were reported containing cytosine-cytosine base-pair mismatch (i-motif), and their single-crystal structures and chiralities were studied. The precise control over the formation of the i-motif was demonstrated, in which the regulating of supramolecular interactions was achieved based on molecular design. In addition, the chiralities of these coordination polymers were investigated according to their crystal structures and solution- and solid-state circular dichroism spectroscopy. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Complexation of Lanthanides with Nitrate at Variable Temperatures: Thermodynamics and Coordination Modes

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Linfeng; Tian, Guoxin

    2008-12-10

    Complexation of neodymium(III) with nitrate was studied at variable temperatures (25, 40, 55 and 70 C) by spectrophotometry and microcalorimetry. The NdNO{sub 3}{sup 2+} complex is weak and becomes slightly stronger as the temperature is increased. The enthalpy of complexation at 25 C was determined by microcalorimetry to be small and positive, (1.5 {+-} 0.2) kJ {center_dot} mol{sup -1}, in good agreement with the trend of the stability constant at variable temperatures. Luminescence emission spectra and lifetime of Eu(III) in nitrate solutions suggest that inner-sphere and bidentate complexes form between trivalent lanthanides (Nd{sup 3+} and Eu{sup 3+}) and nitrate in aqueous solutions. Specific Ion Interaction approach (SIT) was used to obtain the stability constants of NdNO{sub 3}{sup 2+} at infinite dilution and variable temperatures.

  14. Structural Investigation in Solution of a series of five-Coordinate Bisphosphinoaryl Ruthenium(II) Complexes

    NARCIS (Netherlands)

    Koten, G. van; Dani, P.; Kink, G. van

    2000-01-01

    The structure of the ruthenium(II) complexes [RuCl{C6H2(CH2PPh2)2-2,6-R-4}(PPh3)] [R = H (1), Ph (2) or Br (3)] was investigated in solution using two-dimensional NMR techniques (1H-1H-, 13C-1H- and 31P-1H-correlation NMR spectroscopy and 1H NOESY). The 1H and 13C NMR spectra of the complexes 1-3

  15. A New Polynuclear Coordination Type for (Salicylaldoxime)copper(II) Complexes: Structure and Magnetic Properties of an (Oxime)Cu6 Cluster

    DEFF Research Database (Denmark)

    Wenzel, Marco; Forgan, Ross S.; Faure, Anaëlle

    2009-01-01

    A previously unseen coordination mode is reported for (salicylaldoxime)copper complexes utilising a linked zwitterionic NO22- donor set. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)......A previously unseen coordination mode is reported for (salicylaldoxime)copper complexes utilising a linked zwitterionic NO22- donor set. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)...

  16. Coordination of 1,4-Diazabutadiene Ligands to Decamethylytterbocene: Additional Examples of Spin Coupling in Ytterbocene Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Richard; Walter, Marc D.; Berg, David J.; Andersen, Richard A.

    2006-11-04

    The paramagnetic 1:1 coordination complexes of (C5Me5)2Yb with a series of diazabutadiene ligands, RN=C(R')C(R')=NR, where R= CMe3, CHMe2, adamantyl, p-tolyl, p-anisyl, and mesityl when R'=H, and R= p-anisyl when R'= Me, have been prepared. The complexes are paramagnetic, but their magnetic moments are less than expected for the two uncoupled spin carriers, (C5Me5)2Yb(III, 4f13) and the diazabutadiene radical anions (S=1/2), which implies exchange coupling between the spins. The variable temperature 1H NMR spectra show that rotation about the R-N bond is hindered and these barriers are estimated. The barriers are largely determined by steric effects but electronic effects are not unimportant.

  17. Synthesis, characterization and antifungal efficacy of C-coordinated O-carboxymethyl chitosan Cu(II) complexes.

    Science.gov (United States)

    Liu, Weixiang; Qin, Yukun; Liu, Song; Xing, Ronge; Yu, Huahua; Chen, Xiaolin; Li, Kecheng; Li, Pengcheng

    2017-03-15

    A novel type of O-carboxymethyl chitosan Schiff bases (O-CSPX) was synthesized via a condensation reaction. After the coordination reaction of cupric ions, Cu(II) complexes (O-CSPX-Cu) were achieved. The theoretical structure of O-CSPX-Cu calculated by Gaussian 09 reveals that the copper ions underwent dsp 2 hybridization, coordinated by the carbon atom in the p-π conjugate group and the oxygen atoms in the acetate ion. Then, the structures were confirmed by FT-IR, 1 H NMR, CP-MAS 13 C NMR, elemental analysis, DSC and XRD. The antifungal properties of O-CSPX-Cu against Phytophthora capsici (P. capsici), Gibberella zeae (G. zeae) and Glomerella cingulata (G. cingulata) were evaluated at concentrations ranging from 0.05mg/mL to 0.20mg/mL. The experiments indicated that the derivatives have significantly enhanced antifungal activity after copper ion complexation compared with the original chitosan. Moreover, it was shown that 0.20mg/mL of O-CSP3-Cu and O-CSP4-Cu can 100% inhibit the growth of P. capsici. The experimental results reveal that the antifungal efficiency is related to the space steric hindrance on the benzene ring, which may provide a novel direction for the development of copper fungicides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Aging induced loss of complexity and dedifferentiation: consequences for coordination dynamics within and between brain, muscular and behavioral levels.

    Science.gov (United States)

    Sleimen-Malkoun, Rita; Temprado, Jean-Jacques; Hong, S Lee

    2014-01-01

    Growing evidence demonstrates that aging not only leads to structural and functional alterations of individual components of the neuro-musculo-skeletal system (NMSS) but also results in a systemic re-organization of interactions within and between the different levels and functional domains. Understanding the principles that drive the dynamics of these re-organizations is an important challenge for aging research. The present Hypothesis and Theory paper is a contribution in this direction. We propose that age-related declines in brain and behavior that have been characterized in the literature as dedifferentiation and the loss of complexity (LOC) are: (i) synonymous; and (ii) integrated. We argue that a causal link between the aforementioned phenomena exists, evident in the dynamic changes occurring in the aging NMSS. Through models and methods provided by a dynamical systems approach to coordination processes in complex living systems, we: (i) formalize operational hypotheses about the general principles of changes in cross-level and cross-domain interactions during aging; and (ii) develop a theory of the aging NMSS based on the combination of the frameworks of coordination dynamics (CD), dedifferentiation, and LOC. Finally, we provide operational predictions in the study of aging at neural, muscular, and behavioral levels, which lead to testable hypotheses and an experimental agenda to explore the link between CD, LOC and dedifferentiation within and between these different levels.

  19. A Coordination Chemistry Approach to Fine-Tune the Physicochemical Parameters of Lanthanide Complexes Relevant to Medical Applications.

    Science.gov (United States)

    Le Fur, Mariane; Molnár, Enikő; Beyler, Maryline; Kálmán, Ferenc K; Fougère, Olivier; Esteban-Gómez, David; Rousseaux, Olivier; Tripier, Raphaël; Tircsó, Gyula; Platas-Iglesias, Carlos

    2018-03-02

    The geometric features of two pyclen-based ligands possessing identical donor atoms but different site organization have a profound impact in their complexation properties toward lanthanide ions. The ligand containing two acetate groups and a picolinate arm arranged in a symmetrical fashion (L1) forms a Gd 3+ complex being two orders of magnitude less stable than its dissymmetric analogue GdL2. Besides, GdL1 experiences a much faster dissociation following the acid-catalyzed mechanism than GdL2. On the contrary, GdL1 exhibits a lower exchange rate of the coordinated water molecule compared to GdL2. These very different properties are related to different strengths of the Gd-ligand bonds associated to steric effects, which hinder the coordination of a water molecule in GdL2 and the binding of acetate groups in GdL1. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Multidisciplinary management of pregnancy in complex congenital heart disease: a model for coordination of care.

    Science.gov (United States)

    Harris, Rachel C; Fries, Melissa H; Boyle, Annelee; Adeniji-Adele, Hassan; Cherian, Zacharia; Klein, Nancy; John, Anitha S

    2014-01-01

    With advancements in medical care, many women with complex congenital heart disease (CHD) are now living into adulthood and childbearing years. The strains of pregnancy and parturition can be dangerous in such patients, and careful interdisciplinary plans must be made to optimize maternal and fetal health through this process. Several large studies have been published regarding risk prediction and medical management of pregnancy in complex CHD, though few case studies detailing clinical care plans have been published. The objective of this report is to describe the process of developing a detailed pregnancy and delivery care plan for three women with complex CHD, including perspectives from the multidisciplinary specialists involved in the process. This article demonstrates that collaboration between specialists in the fields of cardiology, anesthesiology, high-risk obstetrics, maternal fetal medicine, and neonatology results in clinically successful individualized treatment plans for the management of pregnancy in complex CHD. Multidisciplinary collaboration is a crucial element in the management of pregnancy in complex CHD. We provide a template used in three cases which can serve as a model for the design of future care plans. © 2014 Wiley Periodicals, Inc.

  1. Tracking excited-state charge and spin dynamics in iron coordination complexes

    DEFF Research Database (Denmark)

    Zhang, Wenkai; Alonso-Mori, Roberto; Bergmann, Uwe

    2014-01-01

    to spin state, can elucidate the spin crossover dynamics of [Fe(2,2'-bipyridine)(3)](2+) on photoinduced metal-to-ligand charge transfer excitation. We are able to track the charge and spin dynamics, and establish the critical role of intermediate spin states in the crossover mechanism. We anticipate......Crucial to many light-driven processes in transition metal complexes is the absorption and dissipation of energy by 3d electrons(1-4). But a detailed understanding of such non-equilibrium excited-state dynamics and their interplay with structural changes is challenging: a multitude of excited...... states and possible transitions result in phenomena too complex to unravel when faced with the indirect sensitivity of optical spectroscopy to spin dynamics(5) and the flux limitations of ultrafast X-ray sources(6,7). Such a situation exists for archetypal poly-pyridyl iron complexes, such as [Fe(2...

  2. The coordination structure of the extracted copper(II) complex with a synergistic mixture containing dinonylnaphthalene sulfonic acid and n-hexyl 3-pyridinecarboxylate ester

    Science.gov (United States)

    Zhu, Shan; Hu, Huiping; Hu, Jiugang; Li, Jiyuan; Hu, Fang; Wang, Yongxi

    2017-09-01

    In continuation of our interest in the coordination structure of the nickel(II) complex with dinonylnaphthalene sulfonic acid (HDNNS) and 2-ethylhexyl 4-pyridinecarboxylate ester (4PC), it was observed that the coordination sphere was completed by the coordination of two N atoms of pyridine rings in ligands 4PC and four water molecules while no direct interaction between Ni(II) and deprotonated HDNNS was observed. To investigate whether the coordination structure of nickel(II) with the synergistic mixture containing HDNNS and 4PC predominates or not in the copper(II) complex with the synergistic mixtures containing HDNNS and pyridinecarboxylate esters, a copper(II) synergist complex with n-hexyl 3-pyridinecarboxylate ester (L) and naphthalene-2-sulfonic acid (HNS, the short chain analogue of HDNNS), was prepared and studied by X-ray single crystal diffraction, elemental analyses and thermo gravimetric analysis (TGA), respectively. It was shown that the composition of the copper(II) synergist complex was [Cu(H2O)2(L)2(NS)2] and formed a trans-form distorted octahedral coordination structure. Two oxygen atoms of the two coordinated water molecules and two N atoms of the pyridine rings in the ligands L defined the basal plane while two O atoms from two sulfonate anions of the deprotonated HNS ligands occupied the apical positions by direct coordination with Cu(II), which was distinguished from the coordination structure of the nickel(II) synergist complex as reported in our previous work. In the crystal lattice, neighboring molecules [Cu(H2O)2L2(NS)2] were linked through the intermolecular hydrogen bonds between the hydrogen atoms of the coordinated water molecules and the oxygen atoms of the sulfonate anions in the copper(II) synergist complex to form a 2D plane. In order to bridge the gap between the solid state structure of the copper(II) synergist complex and the solution structure of the extracted copper(II) complex with the actual synergistic mixture containing

  3. Condition-based maintenance for complex systems : Coordinating maintenance and logistics planning for the process industries

    NARCIS (Netherlands)

    Olde Keizer, Minou Catharina Anselma

    2016-01-01

    Maintenance planning in the process industries is extremely complex for various reasons. Plants often run nonstop, allowing little time for performing preventive maintenance. Failures should be prevented, however, as they can lead to system downtime and high losses of revenue. Corrective maintenance

  4. School Nurses and Care Coordination for Children with Complex Needs: An Integrative Review

    Science.gov (United States)

    McClanahan, Rachel; Weismuller, Penny C.

    2015-01-01

    Health care for students with chronic needs can be complex and specialized, resulting in fragmentation, duplication, and inefficiencies. Students who miss school due to chronic conditions lose valuable educational exposure that contributes to academic success. As health-related disabilities increase in prevalence so does the need for the…

  5. An Iminosemiquinone-Coordinated Oxidovanadium(V) Complex: A Combined Experimental and Computational Study

    Czech Academy of Sciences Publication Activity Database

    Sarkar, P.; Mondal, M. K.; Sarmah, Amrit; Maity, S.; Mukherjee, C.

    2017-01-01

    Roč. 56, č. 14 (2017), s. 8068-8077 ISSN 0020-1669 Institutional support: RVO:61388963 Keywords : transition metal complexes * induced electron transfer * non-innocent ligands Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.857, year: 2016

  6. Coordination chemistry and catalytic activity of N-heterocyclic carbene iridium(I) complexes.

    Science.gov (United States)

    Fu, Ching-Feng; Chang, Yung-Hung; Liu, Yi-Hong; Peng, Shei-Ming; Elsevier, Cornelis J; Chen, Jwu-Ting; Liu, Shiuh-Tzung

    2009-09-21

    Iridium complexes [(CO)2Ir(NHC-R)Cl] (R = Et-, 3a; PhCH2-, 3b; CH3OCH2CH2-, 3c; o-CH3OC6H4CH2-, 3d; NHC: N-heterocyclic carbene) are prepared via the carbene transfer from [(NHC-R)W(CO)5] to [Ir(COD)Cl]2. By using substitution with 13CO, we are able to estimate the activation energy (G) of the CO-exchange in 3a-d, which are in the range of 12-13 kcal mol-1, significantly higher than those for the phosphine analog [(CO)2Ir(PCy3)Cl]. Reactions of 3b and 3d with an equimolar amount of PPh3 result in the formation of the corresponding [(NHC-R)Ir(CO)(PPh3)Cl] with the phosphine and NHC in trans arrangement. In contrast, the analogous reaction of 3a or 3c with phosphine undergoes substitution followed by the anion metathesis to yield the corresponding di-substituted [(NHC-R)Ir(CO)(PPh3)2]BF4 (5) directly. Treatment of 3b or 3d with excess of PPh3 leads to the similar product of disubstitution 5b and 5d. The analysis for the IR data of carbonyliridium complexes provides the estimation of electron-donating power of NHCs versus phosphines. The NHC moiety on the iridium center cannot be replaced by phosphines, even 1,2-bis(diphenylphohino)ethane (dppe). All the carbene moieties on the iridium complexes are inert toward sulfur treatment, indicating a strong interaction between NHC and the iridium centers. Complexes 3a-c are active on the catalysis of the oxidative cyclization of 2-(o-aminophenyl)ethanol to yield the indole compound. The phosphine substituted complexes or analogs are less active.

  7. Synthesis and coordination behavior of a bipyridine platinum(II) complex with thioglucose.

    Science.gov (United States)

    Tsuji, Takaaki; Kuwamura, Naoto; Yoshinari, Nobuto; Konno, Takumi

    2013-05-06

    A mononuclear platinum(II) complex with two monodentate-S H4tg(-) ligands, [Pt(H4tg-κS)2(bpy)] (1), was newly synthesized by the reaction of [PtCl2(bpy)] (bpy = 2,2'-bipyridyl) with NaH4tg (NaH4tg =1-thio-β-d-glucose sodium salt) in water. Complex 1 reacted with additional [PtCl2(bpy)] in water to give an S-bridged dinuclear complex, [Pt2(μ2-H4tg-κ(1)S:κ(1)S)2(bpy)2](2+) ([2](2+)), in which a square-planar [Pt(H4tg)2(bpy)] unit binds to a [Pt(bpy)](2+) moiety through two thiolato groups. Treatments of 1 with Cu(2+) and Ni(2+) in water in the presence of bpy produced S-bridged dinuclear complexes [PtCu(μ2-H4tg-κ(1)S:κ(2)O,S)2(bpy)2](2+) ([3](2+)) and [PtNi(μ2-H4tg-κ(1)S:κ(2)O,S)2(bpy)2](2+) ([4](2+)), respectively, in which a square-planar [Pt(H4tg)2(bpy)] unit binds to a [M(bpy)](2+) (M = Cu(II), Ni(II)) moiety through two thiolato and two hydroxyl groups to form a chiral [M(N)2(O)2(S)2] octahedron with the Δ configuration. On the other hand, similar treatment with Cd(2+) in the presence of bpy resulted in the formation of an S-bridged trinuclear complex, [Cd{Pt(μ2-H4tg-κ(1)S:κ(2)O,S)(μ2-H4tg-κ(1)S:κ(1)S)(bpy)}2](2+) ([5](2+)), in which each of two square-planar [Pt(H4tg)2(bpy)] units binds to a Cd(II) ion through two thiolato groups and one hydroxyl group to form a chiral [Cd(O)2(S)4] octahedron with the Λ configuration. Of two geometrical configurations, syn and anti, which arise from the relative arrangement of two β-D-pyranose moieties, [2](2+) adopts the syn configuration with symmetric bridging sulfur atoms, while [3](2+), [4](2+), and [5](2+) all have the anti configuration with R configurational bridging sulfur atoms. All of the complexes were fully characterized by electronic absorption, CD, and NMR spectroscopies, along with single-crystal X-ray crystallography.

  8. Coordination of bis(tricarbonylchromium) complexes to small polycyclic aromatic hydrocarbons: Structure, relative stabilities, and bonding

    Science.gov (United States)

    Jiménez-Halla, J. Oscar C.; Robles, Juvencio; Solà, Miquel

    2008-11-01

    Bis(tricarbonylchromium) complexes of two- to four-fused benzenoid rings were investigated by means of the B3LYP method. Our analysis was focused on both the molecular structure of the different isomers and their relative energies. For all the studied cases, the isomer with the lowest energy resulted to be the anti where both Cr(CO) 3 units are bonded to the most external rings. According to the calculated dissociation energies for the lowest energy isomers, stabilization due to metal bicomplexation is similar in angular and linear polycyclic aromatic hydrocarbons (PAH), while the less energetically favorable complexation occurs in PAH with a compact arrangement of six-membered rings like in pyrene.

  9. Coordinated aqua vs methanol substitution kinetics in fac-Re(I) tricarbonyl tropolonato complexes.

    Science.gov (United States)

    Schutte, Marietjie; Roodt, Andreas; Visser, Hendrik G

    2012-11-05

    Water-soluble fac-[Re(CO)(3)(L,L'-Bid)(X)] (L,L'-Bid = tropolonato, X = H(2)O, methanol) complexes have been synthesized, and the aqua and methanol substitution reactions were investigated in water (pH range 6.3-10.0) and methanol, respectively, and compared. Thiocyanate ions were used as monodentate entering ligand. The complexes were characterized by UV-vis, IR, and NMR spectroscopy. The crystal structures of the complexes [NEt(4)] fac-[Re(Trop)(CO)(3)(H(2)O)].NO(3).H(2)O (reactant) and fac-[Re(CO)(3)(Trop)(Py)], a substitution product, are reported. Overall it was found that the aqua substitution of fac-[Re(CO)(3)(Trop)(H(2)O)] is about 10 times faster than the methanol substitution reaction for fac-[Re(CO)(3)(Trop)(MeOH)], with forward and reverse rate and stability constants [k(1) (M(-1) s(-1)), k(-1) (s(-1)), K(1), (M(-1))] for thiocyanate as monodentate entering ligand as follows: fac-[Re(CO)(3)(Trop)(H(2)O)] = 2.54 ± 0.03, 0.0077 ± 0.0005, 330 ± 22/207 ± 14 and fac-[Re(CO)(3)(Trop)(MeOH)] = 0.268 ± 0.002, 0.0044 ± 0.0002, (61 ± 3)/(52 ± 4). The activation parameters [ΔH(‡)(k1) (kJ mol(-1)), ΔS(‡)(k1) (J K(-1) mol(-1))] for the aqua and methanol complex respectively are 56.1 ± 0.7, -49 ± 2 and 64 ± 1, -43 ± 5.

  10. Broad-Complex acts downstream of Met in juvenile hormone signaling to coordinate primitive holometabolan metamorphosis

    Czech Academy of Sciences Publication Activity Database

    Konopová, Barbora; Jindra, Marek

    2008-01-01

    Roč. 135, č. 3 (2008), s. 559-568 ISSN 0950-1991 R&D Projects: GA ČR(CZ) GA204/07/1032; GA AV ČR IAA5007305; GA MŠk LC07032 Institutional research plan: CEZ:AV0Z50070508 Keywords : metamorphosis * juvenile hormone * broad-complex Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.812, year: 2008

  11. Synthesis and characterisation of mono-nitrosyl complexes of ruthenium: reactivity of the coordinated nitrosyl

    International Nuclear Information System (INIS)

    Sueur, Stephane

    1977-01-01

    Within the frame of physical-chemical researches on radioactive effluents, their processing and their evolution, and within the perspective of a possible application to the fixing of radioactive ruthenium, this research thesis reports the study of reactions of barbituric acid with nitro-complexes of ruthenium-nitrosyl. First, the synthesis and the complete study of ketoxime complexes of ruthenium II have been performed. A radio-crystallographic study of HRu(H 2 vi) 3 ,4H 2 O allows the crystallisation of this compound and the molecular structure of Ru(H 2 vi) 3 - to be analysed. Nuclear magnetic resonance has been used to study this ion: the 'cis' structure noticed in solid phase remains present in solution. Spectroscopic studies (IR and FIR) have also been performed to further study the structure and of these tris-chelates. Their stoichiometry and titration have also been studied. The same techniques have then been applied to nitrosyl complexes for their synthesis, characterisation and structural study, and finally to the study of reactions of K 2 RuNOCl 5 and Na 2 RuNo(NO 2 ) 4 OH with barbituric acid

  12. Spontaneous Partitioning of Californium from Curium: Curious Cases from the Crystallization of Curium Coordination Complexes.

    Science.gov (United States)

    Cary, Samantha K; Silver, Mark A; Liu, Guokui; Wang, Jamie C; Bogart, Justin A; Stritzinger, Jared T; Arico, Alexandra A; Hanson, Kenneth; Schelter, Eric J; Albrecht-Schmitt, Thomas E

    2015-12-07

    The reaction of (248)CmCl3 with excess 2,6-pyridinedicarboxylic acid (DPA) under mild solvothermal conditions results in crystallization of the tris-chelate complex Cm(HDPA)3 · H2O. Approximately half of the curium remains in solution at the end of this process, and evaporation of the mother liquor results in crystallization of the bis-chelate complex [Cm(HDPA)(H2DPA)(H2O)2Cl]Cl·2H2O. (248)Cm is the daughter of the α decay of (252)Cf and is extracted in high purity from this parent. However, trace amounts of (249,250,251)Cf are still present in all samples of (248)Cm. During the crystallization of Cm(HDPA)3 · H2O and [Cm(HDPA)(H2DPA)(H2O)2Cl]Cl · 2H2O, californium(III) spontaneously separates itself from the curium complexes and is found doped within crystals of DPA in the form of Cf(HDPA)3. These results add to the growing body of evidence that the chemistry of californium is fundamentally different from that of earlier actinides.

  13. Basicity of coordinating ligands in trivalent uranium and cerium metallocene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Fabiano, M.D.

    1988-09-01

    Although much is known about the affinity of various Lewis bases for transition metal centers, the chemical literature contains only scant information about the relative affinities of Lewis bases for lanthanide and actinide metal centers. In terms of ligand affinities for f-metal centers, traditional HSAB theory characterizes trivalent and tetravalent f-metal cations as ''hard'' acids, preferring to be coordinated to ''hard'' Lewis bases (e.g., nitrogen or oxygen donor ligands) rather than ''soft'' (e.g., phosphorous or sulfur donor ligands) Lewis bases. Recent work by Brennan and Stults, however, has shown that, trimethylphosphine has a much greater affinity than does pyridine for the metal center in (MeC/sub 5/H/sub 4/)/sub 3/U and in (MeC/sub 5/H/sub 4/)/sub 3/Ce. This work established the ligand displacement series PMe/sub 3/, is quantitatively displaced by trimethylphosphine oxide in both the uranium and cerium systems. In the cerium system, trimethylphosphine sulfide and dimethyl sulfoxide were also found to quantitatively displace PMe/sub 3/. Trimethylphosphine oxide was found to be by far the strongest ligand in both systems, quantitatively displacing all ligands studied in both systems, with one exception: in the (me/sub 3/SiC/sub 5/H/sub 4/)/sub 3/U system, t-butyl isocyanide is displaced, but not completely displaced, by OPME/sub 3/. 9 refs.

  14. The Electronic Structure of Mn in Oxides, Coordination Complexes, and the Oxygen-Evolving Complex of Photosystem II Studied by Resonant Inelastic X-ray Scattering

    Science.gov (United States)

    Yano, Junko; Visser, Hendrik; Robblee, John H.; Gu, Weiwei; de Groot, Frank M. F.; Christou, George; Pecoraro, Vincent L.

    2014-01-01

    Resonant inelastic X-ray scattering (RIXS) was used to collect Mn K pre-edge spectra and to study the electronic structure in oxides, molecular coordination complexes, as well as the S1 and S2 states of the oxygen-evolving complex (OEC) of photosystem II (PS II). The RIXS data yield two-dimensional plots that can be interpreted along the incident (absorption) energy or the energy transfer axis. The second energy dimension separates the pre-edge (predominantly 1s to 3d transitions) from the main K-edge, and a detailed analysis is thus possible. The 1s2p RIXS final-state electron configuration along the energy transfer axis is identical to conventional L-edge absorption spectroscopy, and the RIXS spectra are therefore sensitive to the Mn spin state. This new technique thus yields information on the electronic structure that is not accessible in conventional K-edge absorption spectroscopy. The line splittings can be understood within a ligand field multiplet model, i.e., (3d,3d) and (2p,3d) two-electron interactions are crucial to describe the spectral shapes in all systems. We propose to explain the shift of the K pre-edge absorption energy upon Mn oxidation in terms of the effective number of 3d electrons (fractional 3d orbital population). The spectral changes in the Mn 1s2p3/2 RIXS spectra between the PS II S1 and S2 states are small compared to that of the oxides and two of the coordination complexes (MnIII(acac)3 and MnIV(sal)2(bipy)). We conclude that the electron in the step from S1 to S2 is transferred from a strongly delocalized orbital. PMID:15303869

  15. Manipulating charge transfer excited state relaxation and spin crossover in iron coordination complexes with ligand substitution

    DEFF Research Database (Denmark)

    Zhang, Wenkai; Kjær, Kasper Skov; Alonso-Mori, Roberto

    2017-01-01

    iron complexes with four cyanide (CN-;) ligands and one 2,2′-bipyridine (bpy) ligand. This enables MLCT excited state and metal-centered excited state energies to be manipulated with partial independence and provides a path to suppressing spin crossover. We have combined X-ray Free-Electron Laser (XFEL......) Kβ hard X-ray fluorescence spectroscopy with femtosecond time-resolved UV-visible absorption spectroscopy to characterize the electronic excited state dynamics initiated by MLCT excitation of [Fe(CN)4(bpy)]2-. The two experimental techniques are highly complementary; the time-resolved UV...

  16. A new hybrid optimization algorithm CRO-DE for optimal coordination of overcurrent relays in complex power systems

    Directory of Open Access Journals (Sweden)

    Mohamed Zellagui

    2017-09-01

    Full Text Available The paper presents a new hybrid global optimization algorithm based on Chemical Reaction based Optimization (CRO and Di¤erential evolution (DE algorithm for nonlinear constrained optimization problems. This approach proposed for the optimal coordination and setting relays of directional overcurrent relays in complex power systems. In protection coordination problem, the objective function to be minimized is the sum of the operating time of all main relays. The optimization problem is subject to a number of constraints which are mainly focused on the operation of the backup relay, which should operate if a primary relay fails to respond to the fault near to it, Time Dial Setting (TDS, Plug Setting (PS and the minimum operating time of a relay. The hybrid global proposed optimization algorithm aims to minimize the total operating time of each protection relay. Two systems are used as case study to check the effeciency of the optimization algorithm which are IEEE 4-bus and IEEE 6-bus models. Results are obtained and presented for CRO and DE and hybrid CRO-DE algorithms. The obtained results for the studied cases are compared with those results obtained when using other optimization algorithms which are Teaching Learning-Based Optimization (TLBO, Chaotic Differential Evolution Algorithm (CDEA and Modiffied Differential Evolution Algorithm (MDEA, and Hybrid optimization algorithms (PSO-DE, IA-PSO, and BFOA-PSO. From analysing the obtained results, it has been concluded that hybrid CRO-DO algorithm provides the most optimum solution with the best convergence rate.

  17. Synthesis, Crystal Structure, and Cytotoxic Activity of a Novel Eight-Coordinated Dinuclear Ca(II-Schiff Base Complex

    Directory of Open Access Journals (Sweden)

    Xi-Shi Tai

    2016-09-01

    Full Text Available A novel eight-coordinated dinuclear Ca(II complex, [Ca2(L2(H2O10]·H2O (L = 4-formylbenzene-1,3-disulfonate-3-pyridinecarboxylic hydrazone (1, was synthesized by the reaction of 3-pyridinecarboxylic hydrazide, disodium 4-formylbenzene-1,3-disulfonate, and Ca(ClO42·4H2O in ethanol-water solution (v:v = 3:1 at 50 °C. Complex 1 was characterized by elemental analysis, IR, 1H-NMR, 13C-NMR, and X-ray single crystal diffraction analysis. Dinuclear Ca(II complex 1 belongs to triclinic, space group P-1 with a = 7.186(3 Å, b = 11.978(5 Å, c = 12.263(5 Å, α = 90.318(5°, β = 91.922(5°, γ = 96.797(5°, V = 1047.5(8 Å3, Z = 1, Dc = 1.685 mg·m−3, μ = 0.572 mm−1, F(000 = 552, and final R1 = 0.0308, ωR2 = 0.0770. Dinuclear Ca(II molecules form a 1D chained structure by π–π stacking interaction. The 1D chains form a 3D framework structure by the π–π stacking interaction and hydrogen bonds. The in vitro cytotoxic activity activity of 1 against HL-60 and MLTC-1 was also investigated.

  18. Restoring Lands - Coordinating Science, Politics and Action Complexities of Climate and Governance

    CERN Document Server

    Scarlett, Lynn; Vargas-Moreno, Juan; Flaxman, Michael

    2012-01-01

    Environmental issues, vast and varied in their details, unfold at the confluence of people and place. They present complexities in their biophysical details, their scope and scale, and the dynamic character of human action and natural systems. Addressing environmental issues often invokes tensions among battling interests and competing priorities. Air and water pollution, the effects of climate change, ecosystem transformations—these and other environmental issues involve scientific, social, economic, and institutional challenges. This book analyzes why tackling many of these problems is so difficult and why sustainability involves more than adoption of greener, cleaner technologies. Sustainability, as discussed in this book, involves knowledge flows and collaborative decision processes that integrate scientific and technological methods and tools, political and governance structures and regimes, and social and community values. The authors synthesize a holistic and adaptive approach to rethinking the frame...

  19. Care Coordination for Children with Complex Special Health Care Needs: The Value of the Advanced Practice Nurse’s Enhanced Scope of Knowledge and Practice

    Science.gov (United States)

    Looman, Wendy S.; Presler, Elizabeth; Erickson, Mary M.; Garwick, Ann E.; Cady, Rhonda G.; Kelly, Anne M.; Finkelstein, Stanley M.

    2012-01-01

    Efficiency and effectiveness of care coordination depends on a match between the needs of the population and the skills, scope of practice, and intensity of services provided by the care coordinator. There is limited existing literature that addresses the relevance of the APN role as a fit for coordination of care for children with SHCN. The objective of this paper is to describe the value of the advanced practice nurse’s (APN’s) enhanced scope of knowledge and practice for relationship-based care coordination in healthcare homes that serve children with complex special health care needs (SHCN). The TeleFamilies project is provided as an example of the integration of an APN care coordinator in a healthcare home for children with SHCN. PMID:22560803

  20. Two mechanisms coordinate replication termination by the Escherichia coli Tus-Ter complex.

    Science.gov (United States)

    Pandey, Manjula; Elshenawy, Mohamed M; Jergic, Slobodan; Takahashi, Masateru; Dixon, Nicholas E; Hamdan, Samir M; Patel, Smita S

    2015-07-13

    The Escherichia coli replication terminator protein (Tus) binds to Ter sequences to block replication forks approaching from one direction. Here, we used single molecule and transient state kinetics to study responses of the heterologous phage T7 replisome to the Tus-Ter complex. The T7 replisome was arrested at the non-permissive end of Tus-Ter in a manner that is explained by a composite mousetrap and dynamic clamp model. An unpaired C(6) that forms a lock by binding into the cytosine binding pocket of Tus was most effective in arresting the replisome and mutation of C(6) removed the barrier. Isolated helicase was also blocked at the non-permissive end, but unexpectedly the isolated polymerase was not, unless C(6) was unpaired. Instead, the polymerase was blocked at the permissive end. This indicates that the Tus-Ter mechanism is sensitive to the translocation polarity of the DNA motor. The polymerase tracking along the template strand traps the C(6) to prevent lock formation; the helicase tracking along the other strand traps the complementary G(6) to aid lock formation. Our results are consistent with the model where strand separation by the helicase unpairs the GC(6) base pair and triggers lock formation immediately before the polymerase can sequester the C(6) base. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  1. Structure and stereochemistry in f-block complexes of high co-ordination number

    International Nuclear Information System (INIS)

    Kepert, D.L.; Patrick, J.M.; White, A.H.

    1983-01-01

    The crystal structure of [Usup(IV)(PhCOCHCOPh)4- has been determined at 295 K from X-ray diffraction data refined by least squares to a residual of 0.042 for 2 257 'observed' reflections. Crystals are orthorhombic, space group Pccn, with unit-cell dimensions a = 10.323(8), b = 20.172(15), c = 23.65(2) A, and Z = 4; they are isostructural with the previously studied cerium analogue, the eight-co-ordinate uranium atom lying on a crystallographic two-fold axis, with U - O ranging from 2.323(7) to 2.370(6) A. For the cerium analogue, a = 10.29(1), b = 20.07(3), and c = 23.42(4) A; R = 0.043 for 1 817 'observed' reflections. The corresponding Ce - O distances lie between 2.291(7) and 2.348(6) A. The stereochemistries of these complexes are close to square antiprismatic with the bidentate ligands spanning opposite square faces, as predicted by electron-pair repulsion theory. (author)

  2. Two mechanisms coordinate replication termination by the Escherichia coli Tus–Ter complex

    KAUST Repository

    Pandey, Manjula

    2015-07-13

    The Escherichia coli replication terminator protein (Tus) binds to Ter sequences to block replication forks approaching from one direction. Here, we used single molecule and transient state kinetics to study responses of the heterologous phage T7 replisome to the Tus–Ter complex. The T7 replisome was arrested at the non-permissive end of Tus–Ter in a manner that is explained by a composite mousetrap and dynamic clamp model. An unpaired C(6) that forms a lock by binding into the cytosine binding pocket of Tus was most effective in arresting the replisome and mutation of C(6) removed the barrier. Isolated helicase was also blocked at the non-permissive end, but unexpectedly the isolated polymerase was not, unless C(6) was unpaired. Instead, the polymerase was blocked at the permissive end. This indicates that the Tus–Ter mechanism is sensitive to the translocation polarity of the DNA motor. The polymerase tracking along the template strand traps the C(6) to prevent lock formation; the helicase tracking along the other strand traps the complementary G(6) to aid lock formation. Our results are consistent with the model where strand separation by the helicase unpairs the GC(6) base pair and triggers lock formation immediately before the polymerase can sequester the C(6) base.

  3. Investigation on Inter-Limb Coordination and Motion Stability, Intensity and Complexity of Trunk and Limbs during Hands-Knees Crawling in Human Adults.

    Science.gov (United States)

    Ma, Shenglan; Chen, Xiang; Cao, Shuai; Yu, Yi; Zhang, Xu

    2017-03-28

    This study aimed to investigate the inter-limb coordination pattern and the stability, intensity, and complexity of the trunk and limbs motions in human crawling under different speeds. Thirty healthy human adults finished hands-knees crawling trials on a treadmill at six different speeds (from 1 km/h to 2.5 km/h). A home-made multi-channel acquisition system consisting of five 3-axis accelerometers (ACC) and four force sensors was used for the data collection. Ipsilateral phase lag was used to represent inter-limb coordination pattern during crawling and power, harmonic ratio, and sample entropy of acceleration signals were adopted to depict the motion intensity, stability, and complexity of trunk and limbs respectively. Our results revealed some relationships between inter-limb coordination patterns and the stability and complexity of trunk movement. Trot-like crawling pattern was found to be the most stable and regular one at low speed in the view of trunk movement, and no-limb-pairing pattern showed the lowest stability and the greatest complexity at high speed. These relationships could be used to explain why subjects tended to avoid no-limb-pairing pattern when speed was over 2 km/h no matter which coordination type they used at low speeds. This also provided the evidence that the central nervous system (CNS) chose a stable inter-limb coordination pattern to keep the body safe and avoid tumbling. Although considerable progress has been made in the study of four-limb locomotion, much less is known about the reasons for the variety of inter-limb coordination. The research results of the exploration on the inter-limb coordination pattern choice during crawling from the standpoint of the motion stability, intensity, and complexity of trunk and limbs sheds light on the underlying motor control strategy of the human CNS and has important significance in the fields of clinical diagnosis, rehabilitation engineering, and kinematics research.

  4. One novel 1D coordination polymer with parallel dinuclear copper(II) macrocyclic platforms bridged by trans dimeric half-water molecules and two dinuclear copper(II) macrocyclic complexes with different coordination geometry obtained from different solvents

    Science.gov (United States)

    Chu, Zhaolian; You, Wei; Huang, Wei

    2009-02-01

    Three dinuclear copper(II) macrocyclic complexes, formulated as [Cu 2L(N 3) 2(0.5H 2O) 2] n ( 1), [Cu 2L(ClO 4) 2(CH 3CH 2OH)] ( 2) and [Cu 2L(CH 3OH) 2](ClO 4) 2 ( 3) (LH 2 = [2+2] Schiff base macrocyclic ligand condensed from 4-chloro-2,6-diformylphenol and 1,3-diaminopropane), have been prepared and determined by X-ray single-crystal diffraction. Complex 1 shows two six-coordinate Cu(II) centers in which two monodentate N3- anions and two half-water molecules are bonded at the apical positions in the trans configuration. Furthermore, the dimeric half-water molecules serve as a μ2-bridge linking adjacent macrocyclic units together with the multiple O sbnd H…N hydrogen bonds with azide anions, forming a novel 1D chain-like coordination polymer. Complexes 2 and 3 are obtained from different solvents (ethanol and methanol) and they can be converted into each other. The molecular structures and packing mode of 2 and 3 are different where six-coordinate and five-coordinate copper(II) centers are present, respectively.

  5. Four-coordinate trispyrazolylboratomanganese and -iron complexes with a pyrazolato co-ligand: syntheses and properties as oxidation catalysts.

    Science.gov (United States)

    Tietz, Thomas; Limberg, Christian; Stösser, Reinhard; Ziemer, Burkhard

    2011-08-29

    A series of complexes of the type [(Tp(R1,R2))M(X)] (Tp = trispyrazolylborato) with R(1)/R(2) combinations Me/tBu, Ph/Me, iPr/iPr, Me/Me and for M = Mn or Fe coordinating [Pz(Me,tBu)](-) (Pz = pyrazolato) or Cl(-) as co-ligand X has been synthesised. Although the chloride complexes were very unreactive and stable in air, the pyrazolato series was far more reactive in contact with oxidants like O(2) and tBuOOH. The [(Tp(R1,R2))M(Pz(Me,tBu))] complexes proved to be active pre-catalysts for the oxidation of cyclohexene with tBuOOH, reaching turnover frequencies (TOFs) ranging between moderate and good in comparison to other manganese catalysts. Cyclohexene-3-one and cyclohexene-3-ol were always found to represent the main products, with cyclohexene oxide occasionally formed as a side product. The ratios of the different oxidation products varied with the reaction conditions: in the case of a peroxide/alkene ratio of 4:1, considerably more ketone than alcohol was obtained and cyclohexene oxide formation was almost negligible, whereas a ratio of 1:10 led to a significant increase of the alcohol proportion and to the formation of at least small amounts of the epoxide. Pre-treatment of the dissolved [(Tp(R1,R2))M(Pz(Me,tBu))] pre-catalysts with O(2) led to product distributions and TOFs that were very similar to those found in the absence of O(2), so that it may be argued that tBuOOH and O(2) both lead to the same active species. The results of EPR spectroscopy and ESI-MS suggest that the initial product of the reaction of [(Tp(Me,Me))Mn(Pz(Me,tBu))] with O(2) contains a Mn(III)(O)(2)Mn(IV) core. Prolonged exposure to O(2) leads to a different dinuclear complex containing three O-bridges and resulting in different TOFs/product distributions. Analogous findings were made for other complexes and formation of these overoxidised products may explain the deviation of the catalytic performances if the reactions are carried out in an O(2) atmosphere. Copyright © 2011 WILEY

  6. Tunable N-substitution in zwitterionic benzoquinonemonoimine derivatives: metal coordination, tandemlike synthesis of zwitterionic metal complexes, and supramolecular structures.

    Science.gov (United States)

    Yang, Qing-Zheng; Siri, Olivier; Braunstein, Pierre

    2005-12-09

    Full details on a very efficient transamination reaction for the synthesis of zwitterionic N,N-dialkyl-2-amino-5-alcoholate-1,4-benzoquinonemonoiminium derivatives [C6H2(=NHR)2(=O)2] 5-16 are reported. The molecular structures of zwitterions 5 (R=CH3) in 5.H2O, 13 (R=CH2CH2OMe), 15 (R=CH2CH2NMe2), and of the parent, unsubstituted system [C6H2(=NH2)2(=O)2] 4 in 4.H2O have been established by single-crystal X-ray diffraction. This one-pot preparation can be carried out in water, MeOH, or EtOH and allows access to new zwitterions with N-substituents bearing functionalities such as -OMe (13), -OH (9-12), NR1R2 with R1 = or not equal R2 (14-16) or an alkene (8), leading to a rich coordination chemistry and allowing fine-tuning of the supramolecular arrangements in the solid state. As previously described for 15, which reacted with Zn(acac)2 to afford the octahedral Zn(II) complex [Zn[C6H2(NCH2CH2NMe2)O(O)(NHCH2CH2NMe2)]2] (20), ligands 13 and 16 with coordinating "arms" afforded with Zn(acac)2 the 2:1 adducts [Zn[C6H2(NCH2CH2X)O(=O)(NHCH2CH2NX)]2] 19 (X=OMe) and 21 (X=NHEt), with N2O4 and N4O2 donor sets around the octahedral Zn(II) center, respectively. Furthermore, zwitterions 15 and 16 reacted with ZnCl2 to give the stable, crystallographically characterized Zn(II) zwitterionic complexes [ZnCl2[C6H2(NCH2CH2NR1R2)O(=O)(NHCH2CH2NHR1R2)

  7. Six, Seven or Eight Coordinate Fe(II) , Co(II) or Ni(II) Complexes of Amide-Appended Tetraazamacrocycles for ParaCEST Thermometry.

    Science.gov (United States)

    Olatunde, Abiola O; Bond, Christopher J; Dorazio, Sarina J; Cox, Jordan M; Benedict, Jason B; Daddario, Michael D; Spernyak, Joseph A; Morrow, Janet R

    2015-12-07

    Fe(II) , Co(II) and Ni(II) complexes of two tetraazamacrocycles (1,4,8,11-tetrakis(carbamoylmethyl)-1,4,8,11-tetraazacyclotetradecane (L1) and 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane (L2) show promise as paraCEST agents for registration of temperature (paraCEST=paramagnetic chemical exchange saturation transfer). The Fe(II) , Co(II) and Ni(II) complexes of L1 show up to four CEST peaks shifted ≤112 ppm, whereas analogous complexes of L2 show only a single CEST peak at ≤69 ppm. Comparison of the temperature coefficients (CT ) of the CEST peaks of [Co(L2)](2+) , [Fe(L2)](2+) , [Ni(L1)](2+) and [Co(L1)](2+) showed that a CEST peak of [Co(L1)](2+) gave the largest CT (-0.66 ppm (o) C(-1) at 4.7 T). NMR spectral and CEST properties of these complexes correspond to coordination complex symmetry as shown by structural data. The [Ni(L1)](2+) and [Co(L1)](2+) complexes have a six-coordinate metal ion bound to the 1-, 4-amide oxygen atoms and four nitrogen atoms of the tetraazamacrocycle. The [Fe(L2)](2+) complex has an unusual eight-coordinate Fe(II) bound to four amide oxygen atoms and four macrocyclic nitrogen atoms. For [Co(L2)](2+) , one structure has seven-coordinate Co(II) with three bound amide pendents and a second structure has a six-coordinate Co(II) with two bound amide pendents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. An Iron Complex with a Bent, O-Coordinated CO2Ligand Discovered by Femtosecond Mid-Infrared Spectroscopy.

    Science.gov (United States)

    Straub, Steffen; Brünker, Paul; Lindner, Jörg; Vöhringer, Peter

    2018-03-06

    The activation of carbon dioxide by transition metals is widely recognized as a key step for utilizing this greenhouse gas as a renewable feedstock for the sustainable production of fine chemicals. However, the dynamics of CO 2 binding and unbinding to and from the ligand sphere of a metal have never been observed in the time domain. The ferrioxalate anion is used in aqueous solution as a unique model system for these dynamics and apply femtosecond UV-pump mid-infrared-probe spectroscopy to explore its photoinduced primary processes in a time-resolved fashion. Following optical excitation, a neutral CO 2 molecule is expelled from the complex within about 500 fs to generate a highly intriguing pentacoordinate ferrous dioxalate that carries a bent carbon dioxide radical anion ligand, that is, a reductively activated form of CO 2 , which is end-on-coordinated to the metal center by one of its two oxygen atoms. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Coordinated rearrangements between cytoplasmic and periplasmic domains of the membrane protein complex ExbB-ExbD of Escherichia coli.

    Science.gov (United States)

    Sverzhinsky, Aleksandr; Fabre, Lucien; Cottreau, Andrew L; Biot-Pelletier, Damien M P; Khalil, Sofia; Bostina, Mihnea; Rouiller, Isabelle; Coulton, James W

    2014-05-06

    Gram-negative bacteria rely on the ExbB-ExbD-TonB system for the import of essential nutrients. Despite decades of research, the stoichiometry, subunit organization, and mechanism of action of the membrane proteins of the Ton system remain unclear. We copurified ExbB with ExbD as an ∼240 kDa protein-detergent complex, measured by light scattering and by native gels. Quantitative Coomassie staining revealed a stoichiometry of ExbB4-ExbD2. Negative stain electron microscopy and 2D analysis showed particles of ∼10 nm diameter in multiple structural states. Nanogold labeling identified the position of the ExbD periplasmic domain. Random conical tilt was used to reconstruct the particles in three structural states followed by sorting of the single particles and refinement of each state. The different states are interpreted by coordinated structural rearrangements between the cytoplasmic domain and the periplasmic domain, concordant with in vivo predictions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. New Ruthenium complexes containing N, P and S-donor type of ligands: coordination chemistry, characterization and application to asymetric and non-asymetric catalysis

    OpenAIRE

    Sala Román, Xavier

    2007-01-01

    Synthesis, spectroscopic characterization and redox properties of a new Ru-H2O complex containing 1,10-phenantroline and the soft [9]aneS3 ligand. Substitution pathways of a new Ru-py complex [Ru(phen)(py)([9]aneS3)]2+ to form the corresponding Ru-MeCN complex through kinetic analysis. Kinetic establishment of a reaction intermediate. Synthesis of new Ru(II) complexes containing the chiral 1,2-bis(oxazolinyl) benzene ligand. Rotationally restricted isomers were produced upon coordination to a...

  11. Synthesis, crystal structures, and urease inhibition of an acetohydroxamate-coordinated oxovanadium(V) complex derived from N'-(3-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide.

    Science.gov (United States)

    Qu, Dan; Niu, Fang; Zhao, Xinlu; Yan, Ke-Xiang; Ye, Yu-Ting; Wang, Jia; Zhang, Mei; You, Zhonglu

    2015-05-01

    A new benzohydrazone compound N'-(3-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H₂L) was prepared. Reaction of H₂L and acetohydroxamic acid (HAHA) with VO(acac)₂ in methanol gave the complex [VOL(AHA)]. Both H₂L and the oxovanadium complex were characterized by elemental analysis, IR, UV-vis and (1)H NMR spectra, and single crystal X-ray diffraction. H₂L was also characterized by high-resolution mass spectrum. Thermal analysis of the oxovanadium complex was carried out. The benzohydrazone ligand, in its dianionic form, coordinates to V atom through the phenolate oxygen, imino nitrogen and enolate oxygen. The acetohydroxamic acid coordinates to V atom through the carbonyl oxygen and deprotonated hydroxyl oxygen. The V atom is in octahedral coordination. H₂L, HAHA and the oxovanadium complex were tested for their urease inhibitory activities. The percent inhibition at concentration of 100 μmol·L(-1) on Helicobacter pylori urease is 78% for the oxovanadium complex. The IC₅₀ value for the complex is 36.5 μmol·L(-1). Molecular docking study was performed to study the inhibition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Solid-state and solution-state coordination chemistry of lanthanide(III) complexes with (pyrazol-1-yl)acetic acid.

    Science.gov (United States)

    Chen, Xiao-Yan; Goff, George S; Scott, Brian L; Janicke, Michael T; Runde, Wolfgang

    2013-03-18

    As a precursor of carboxyl-functionalized task-specific ionic liquids (TSILs) for f-element separations, (pyrazol-1-yl)acetic acid (L) can be deprotonated as a functionalized pyrazolate anion to coordinate with hard metal cations. However, the coordination chemistry of L with f-elements remains unexplored. We reacted L with lanthanides in aqueous solution at pH = 5 and synthesized four lanthanide complexes of general formula [Ln(L)3(H2O)2]·nH2O (1, Ln = La, n = 2; 2, Ln = Ce, n = 2; 3, Ln = Pr, n = 2; 4, Ln = Nd, n = 1). All complexes were characterized by single crystal X-ray diffraction analysis revealing one-dimensional chain formations. Two distinct crystallographic structures are governed by the different coordination modes of carboxylate groups in L: terminal bidentate and bridging tridentate (1-3); terminal bidentate, bridging bidentate, and tridentate coordination in 4. Comparison of the solid state UV-vis-NIR diffuse reflectance spectra with solution state UV-vis-NIR spectra suggests a different species in solution and solid state. The different coordination in solid state and solution was verified by distinctive (13)C NMR signals of the carboxylate groups in the solid state NMR.

  13. Preparation and Reactions of the 1,1-Dithiolato Complexes of Ni(II). An Undergraduate Coordination Chemistry Experiment.

    Science.gov (United States)

    Ballester, L.; Perpinan, M. F.

    1988-01-01

    Described is an undergraduate coordination chemistry experiment that enables students to relate concepts developed in class about the stereochemistry and coordination numbers to the interpretation of the electronic and infrared spectra and their magnetic behavior. Indicates that thermal decomposition and x-ray diffraction studies can also be…

  14. Synthesis and characterization of bright green terbium coordination complex derived from 1,4-bis(carbonylmethyl)terephthalate: Structure and luminescence properties

    Science.gov (United States)

    Ma, Mengjiao; Li, Congcong; Shu, Dengkun; Wang, Chaohua; Xi, Peng

    2018-02-01

    A photoluminescent terbium (Tb) complex involving a novel benzoic-acid compound with a unique coordinated structure, namely 1,4-bis(carbonylmethyl)terephthalate (BCMT), has been designed and synthesized. The new coordinate structure and energy-transfer mechanism between the ligand and Tb(III) ions were investigated in detail. The results demonstrated that the BCMT-Tb(III) complex shows strong fluorescence intensity (4 × 106 a.u.) and long fluorescence lifetime (1.302 ms), owing to the favorable degree of energy matching between the triplet excited level of the ligand and the resonant level of Tb(III) ions. Based on the analysis of three-dimensional luminescence spectra, the as-prepared Tb(III) complex can be effectively excited in the range of 250-310 nm, and it shows high color purity, with a bright green appearance.

  15. Polycations XX: New Monodentate Cationic Ligands and Their Coordination with Ruthenium for the Construction of Complexes Expressing Enhanced Interaction with DNA

    Directory of Open Access Journals (Sweden)

    Leslie Babukutty

    2012-01-01

    Full Text Available Prior investigations from this laboratory concerned with the preparation of new types of organic cations for a variety of biological and nonbiological applications have been extended to the preparation of cation-bearing ligands with nitrogen coordinating sites for use in complexation reactions with ruthenium cores. The syntheses of new cationic ligands as well as ruthenium complexes bearing them are reported here. The introduction of these new types of ligands is intended to provide to the complexes an enhanced ability to interact with DNA, and thereby to have the potential to be enhanced antitumor agents. Preliminary observations of their interactions with DNA are presented.

  16. The influence of structural factors on the solvation and coordination unsaturation of metal complexes of several structurally related alkyl substituted dipyrrolylmethenes-2,2' and porphin

    Science.gov (United States)

    Antina, E. V.; Guseva, G. B.; v'yugin, A. I.; Berezin, M. B.

    2008-05-01

    The literature data and new results of calorimetric studies of the solution of copper(II), cobalt(II), zinc(II), nickel(II), and mercury(II) complexes with 3,3',4,4',5,5'-hexamethyldipyrrolylmethene-2,2'; 3,3',5,5'-tetramethyl-4,4'-diethyldipyrrolylmethene-2,2'; 3,3',5,5'-tetramethyl-4,4'-dibutyldipyrrolylmethene-2,2' (A), and 2,8,12,18-tetramethyl-3,7,13,17-tetrabutylporphin in various organic solvents were used to calculate the enthalpies of transfer Δtr H o from benzene and estimate the contribution of specific solvation caused by the additional coordination (Δc H o) of electron donor solvent molecules (pyridine and dimethylformamide). The greatest degree of coordination unsaturation and ability to extracoordination was characteristic of copper(II) and mercury(II) complexes with ligand A. The influence of the nature of the complex-forming metal, differences in the alkylation of the ligands, solvent properties, and the macrocyclization effect on the solvation and coordination unsaturation of metal complexes was discussed.

  17. (51)V solid-state NMR and density functional theory studies of eight-coordinate non-oxo vanadium complexes: oxidized amavadin.

    Science.gov (United States)

    Ooms, Kristopher J; Bolte, Stephanie E; Baruah, Bharat; Choudhary, Muhammad Aziz; Crans, Debbie C; Polenova, Tatyana

    2009-05-07

    Using (51)V magic angle spinning solid-state NMR spectroscopy and density functional theory calculations we have characterized the chemical shift and quadrupolar coupling parameters for two eight-coordinate vanadium complexes, [PPh(4)][V(v)(HIDPA)(2)] and [PPh(4)][V(v)(HIDA)(2)]; HIDPA = 2,2'-(hydroxyimino)dipropionate and HIDA = 2,2'-(hydroxyimino)diacetate. The coordination geometry under examination is the less common non-oxo eight coordinate distorted dodecahedral geometry that has not been previously investigated by solid-state NMR spectroscopy. Both complexes were isolated by oxidizing their reduced forms: [V(iv)(HIDPA)(2)](2-) and [V(iv)(HIDA)(2)](2-). V(iv)(HIDPA)(2)(2-) is also known as amavadin, a vanadium-containing natural product present in the Amanita muscaria mushroom and is responsible for vanadium accumulation in nature. The quadrupolar coupling constants, C(Q), are found to be moderate, 5.0-6.4 MHz while the chemical shift anisotropies are relatively small for vanadium complexes, -420 and -360 ppm. The isotropic chemical shifts in the solid state are -220 and -228 ppm for the two compounds, and near the chemical shifts observed in solution. Presumably this is a consequence of the combined effects of the increased coordination number and the absence of oxo groups. Density functional theory calculations of the electric field gradient parameters are in good agreement with the NMR results while the chemical shift parameters show some deviation from the experimental values. Future work on this unusual coordination geometry and a combined analysis by solid-state NMR and density functional theory should provide a better understanding of the correlations between experimental NMR parameters and the local structure of the vanadium centers.

  18. Synthesis and Crystal Structure of a Five-Coordinate Complex of Copper(II) with 4-Nitrobenzenesulfonate and 2, 2'-Bipyridine.

    Science.gov (United States)

    Sharif, Mahboubeh A; Tabatabaee, Masoumeh; Beik, Vahideh; Khavasi, Hamid Reza

    2012-06-01

    [Cu(bipy)2Cl](nbs) (1) (bipy = 2,2'-bipyridine, nbs = 4-nitrobenzenesulfonate) was obtained from the reaction of 4-nitrobenzenesulfonyl chloride and 2-amine-4-methylopyridine with CuCl2 in the presence of 2,2'-bipyridine and characterized by elemental analysis, IR spectra and X-ray single-crystal diffraction. The asymmetric unit of (1) contains the cationic complex [Cu(bipy)2Cl]+ and, in the outer coordination sphere, an (nbs)- counter ion.

  19. Unusual saccharin-N,O (carbonyl) coordination in mixed-ligand copper(II) complexes: Synthesis, X-ray crystallography and biological activity

    Science.gov (United States)

    Mokhtaruddin, Nur Shuhada Mohd; Yusof, Enis Nadia Md; Ravoof, Thahira B. S. A.; Tiekink, Edward R. T.; Veerakumarasivam, Abhi; Tahir, Mohamed Ibrahim Mohamed

    2017-07-01

    Three tridentate Schiff bases containing N and S donor atoms were synthesized via the condensation reaction between S-2-methylbenzyldithiocarbazate with 2-acetyl-4-methylpyridine (S2APH); 4-methyl-3-thiosemicarbazide with 2-acetylpyridine (MT2APH) and 4-ethyl-3-thiosemicarbazide with 2-acetylpyridine (ET2APH). Three new, binuclear and mixed-ligand copper(II) complexes with the general formula, [Cu(sac)(L)]2 (sac = saccharinate anion; L = anion of the Schiff base) were then synthesized, and subsequently characterized by IR and UV/Vis spectroscopy as well as by molar conductivity and magnetic susceptibility measurements. The Schiff bases were also spectroscopically characterized using NMR and MS to further confirm their structures. The spectroscopic data indicated that the Schiff bases behaved as a tridentate NNS donor ligands coordinating via the pyridyl-nitrogen, azomethine-nitrogen and thiolate-sulphur atoms. Magnetic data indicated a square pyramidal environment for the complexes and the conductivity values showed that the complexes were essentially non-electrolytes in DMSO. The X-ray crystallographic analysis of one complex, [Cu(sac)(S2AP)]2 showed that the Cu(II) atom was coordinated to the thiolate-S, azomethine-N and pyridyl-N donors of the S2AP Schiff base and to the saccharinate-N from one anion, as well as to the carbonyl-O atom from a symmetry related saccharinate anion yielding a centrosymmetric binuclear complex with a penta-coordinate, square pyramidal geometry. All the copper(II) saccharinate complexes were found to display strong cytotoxic activity against the MCF-7 and MDA-MB-231 human breast cancer cell lines.

  20. Bulky N-Phosphino-Functionalized N-Heterocyclic Carbene Ligands: Synthesis, Ruthenium Coordination Chemistry, and Ruthenium Alkylidene Complexes for Olefin Metathesis.

    Science.gov (United States)

    Brown, Christopher C; Rominger, Frank; Limbach, Michael; Hofmann, Peter

    2015-11-02

    Ruthenium chemistry and applications in catalytic olefin metathesis based on N-phosphino-functionalized N-heterocyclic carbene ligands (NHCPs) are presented. Alkyl NHCP Ru coordination chemistry is described, and access to several potential synthetic precursors for ruthenium alkylidene complexes is outlined, incorporating both trimethylsilyl and phenyl alkylidenes. The Ru alkylidene complexes are evaluated as potential olefin metathesis catalysts and were shown to behave in a latent fashion. They displayed catalytic activity at elevated temperatures for both ring closing metathesis and ring opening metathesis polymerization.

  1. Catalytic one-electron reduction of uranyl(VI) to Group 1 uranyl(V) complexes via Al(III) coordination

    OpenAIRE

    Zegke, Markus; Nichol, Gary S; Arnold, Polly L; Love, Jason B

    2015-01-01

    Reactions between the uranyl(vi) Pacman complex [(UO2)(py)(H2L)] of the Schiff-base polypyrrolic macrocycle L and Tebbe's reagent or DIBAL result in the first selective reductive functionalisation of the uranyl oxo by Al to form [(py)(R2AlOUO)(py)(H2L)] (R = Me or (i)Bu). The clean displacement of the oxo-coordinated Al(iii) by Group 1 cations has enabled the development of a one-pot, DIBAL-catalysed reduction of the U(vi) uranyl complexes to a series of new, mono-oxo alkali-metal-functionali...

  2. Studies on coordination chemistry and bioactivity of metal complexes of some nitrogen-sulfur donor ligands: Section A: hydraziniumdithiocarbazate and its complexes. Section B: complexes of Ni2+ and Cu2+ ions with s-picolyldithiocarbazate

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Liza bt Abdullah; Crouse, Karen A.; Ali, A.M.

    2003-08-01

    Two new nitrogen - sulphur donor ligands, hydraziniumdithiocarbazate(HzDTC) and S-picolyldithiocarbazate(SPDTC), along with three novel Schiff bases were prepared. Complexes of some of HzDTC with nickel(II), zinc(II), and those of SPDTC with nickel(II) and copper(II) were prepared and characterized by a variety of physico- chemical techniques. The ligand, HzDTC, was a potential bidentate and uninegatively charged providing terminal amino and thiolate bindings with the metal ions, while SPDTC coordinates via the pyridine nitrogen and the thiolate anion. All of the compounds were tested against four pathogenic bacteria and fungi. HzDTC was found to be very effective antimicrobial than its complexes. The complexes of SPDTC and the Schiff bases of HzDTC were more antifungal. None of the compounds were effective anti- cancer agents except for [Ni(HzDTCA)Cl.H 2 O], which was moderately active against CEM- SS (Human cell T- lymphoblastic) leukemic cells. (author)

  3. Synthesis, Coordination Chemistry, and Cooperative Activation of H2 with Ruthenium Complexes of ProtonResponsive METAMORPhos Ligands

    NARCIS (Netherlands)

    Terrade, F.G.; Lutz, M.; van der Vlugt, J.I.; Reek, J.N.H.

    2014-01-01

    The synthetic scope of proton-responsive sulfonamidophosphorus (METAMORPhos) ligands is expanded and design principles for the selective formation of particular tautomers, ion pairs, or double condensation products are elucidated. These systems have been introduced in the coordination sphere of Ru

  4. Variable coordination of redox-active TCNB in discrete and polymeric ferrocenylcopper(i) complexes: Structures and spectroelectrochemical behaviour

    Czech Academy of Sciences Publication Activity Database

    Jana, R.; Mobin, S. M.; Schwederski, B.; Fiedler, Jan; Kaim, W.

    2013-01-01

    Roč. 42, č. 45 (2013), s. 16142-16150 ISSN 1477-9226 R&D Projects: GA ČR GA203/09/0705 Institutional support: RVO:61388955 Keywords : Bis(diphenylphosphino) ferrocene * Coordination Polymers * Discrete transitions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.097, year: 2013

  5. Robust Cross-Linked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization.

    Science.gov (United States)

    Vidal, Fernando; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y-X

    2016-08-03

    The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust cross-linked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site-controlled propagation mechanism. Postfunctionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible cross-linked thin-film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Cross-linking of such complexes affords robust cross-linked stereocomplexes that are solvent-resistant and also exhibit considerably enhanced thermal and mechanical properties compared with the un-cross-linked stereocomplexes.

  6. Two novel magnesium(II) meso-tetraphenylporphyrin-based coordination complexes: Syntheses, combined experimental and theoretical structures elucidation, spectroscopy, photophysical properties and antibacterial activity

    Science.gov (United States)

    Amiri, Nesrine; Hajji, Melek; Taheur, Fadia Ben; Chevreux, Sylviane; Roisnel, Thierry; Lemercier, Gilles; Nasri, Habib

    2018-02-01

    Two novel magnesium(II) tetraphenylporphyrin-based six-coordinate complexes; bis(hexamethylenetetramine)(5,10,15,2O tetrakis[4(benzoyloxy)phenyl]porphinato) magnesuim(II) (1) and bis(1,4-diazabicyclo(2.2.2)octane) (5,10,15,2O-tetrakis[4- (benzoyloxy)phenyl]porphinato)magnesium(II) (2) have been synthesised and confirmed by proton nuclear magnetic resonance, mass spectrometry, elemental analysis and IR spectroscopy. Both crystal structures were determined and described by single crystal X-ray diffraction analysis and Hirshfeld surfaces computational method. All Mg(II) atoms are surrounded by four porphyrin nitrogen atoms and two axial ligands coordinated to the metal ion through one nitrogen atom, forming a regular octahedron. In both complexes, molecular structures and three-dimensional framework are stabilised by inter-and intramolecular C-H ⋯O and C-H ⋯N hydrogen bonds, and by weak C-H ⋯Cg π interactions. UV-visible and Fluorescence investigations, respectively, show that studied complexes have a strong absorption in red part and exhibit an emission in the blue region. The HOMO-LUMO energy gap values, modelled using the DFT approach, indicates that both studied compounds can be classified as semiconductors. The role of these complexes as novel antibacterial agents was also performed.

  7. Robust Crosslinked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization

    KAUST Repository

    Vidal, Fernando

    2016-07-07

    The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust crosslinked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site controlled propagation mechanism. Post-functionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible crosslinked thin film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Crosslinking of such complexes afforded robust crosslinked stereocomplexes that are solvent resistant and also exhibit considerably enhanced thermal and mechanical properties as compared to the uncrosslinked stereocompexes.

  8. Characterization of Water Coordination to Ferrous Nitrosyl Complexes with fac-N2O, cis-N2O2, and N2O3 Donor Ligands.

    Science.gov (United States)

    McCracken, John; Cappillino, Patrick J; McNally, Joshua S; Krzyaniak, Matthew D; Howart, Michael; Tarves, Paul C; Caradonna, John P

    2015-07-06

    Electron paramagnetic resonance (EPR) experiments were done on a series of S = (3)/2 ferrous nitrosyl model complexes prepared with chelating ligands that mimic the 2-His-1-carboxylate facial triad iron binding motif of the mononuclear nonheme iron oxidases. These complexes formed a comparative family, {FeNO}(7)(N2Ox)(H2O)3-x with x = 1-3, where the labile coordination sites for the binding of NO and solvent water were fac for x = 1 and cis for x = 2. The continuous-wave EPR spectra of these three complexes were typical of high-spin S = (3)/2 transition-metal ions with resonances near g = 4 and 2. Orientation-selective hyperfine sublevel correlation (HYSCORE) spectra revealed cross peaks arising from the protons of coordinated water in a clean spectral window from g = 3.0 to 2.3. These cross peaks were absent for the {FeNO}(7)(N2O3) complex. HYSCORE spectra were analyzed using a straightforward model for defining the spin Hamiltonian parameters of bound water and showed that, for the {FeNO}(7)(N2O2)(H2O) complex, a single water conformer with an isotropic hyperfine coupling, Aiso = 0.0 ± 0.3 MHz, and a dipolar coupling of T = 4.8 ± 0.2 MHz could account for the data. For the {FeNO}(7)(N2O)(H2O)2 complex, the HYSCORE cross peaks assigned to coordinated water showed more frequency dispersion and were analyzed with discrete orientations and hyperfine couplings for the two water molecules that accounted for the observed orientation-selective contour shapes. The use of three-pulse electron spin echo envelope modulation (ESEEM) data to quantify the number of water ligands coordinated to the {FeNO}(7) centers was explored. For this aspect of the study, HYSCORE spectra were important for defining a spectral window where empirical integration of ESEEM spectra would be the most accurate.

  9. Mixed-valence copper(I,II) complexes with 4-(1H-pyrazol-1-yl)-6-R-pyrimidines: from ionic structures to coordination polymers.

    Science.gov (United States)

    Vinogradova, Katerina A; Krivopalov, Viktor P; Nikolaenkova, Elena B; Pervukhina, Natalia V; Naumov, Dmitrii Yu; Boguslavsky, Evgenii G; Bushuev, Mark B

    2016-01-14

    Two pyrimidine-based ligands, 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(morpholino)pyrimidine () and 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-phenoxypyrimidine (), and a series of mixed-valence copper(i,ii) halide complexes, [Cu(L(2))2Br]2[Cu2Br4] (), [Cu(L(2))2Cl][CuCl2] (), and [Cu2L(3)Br3]n (), have been synthesized. The complex [Cu(L(2))2Br]2[Cu2Br4] was prepared by the reaction of with CuBr2 in a 1 : 1 molar ratio in MeCN. Its chlorido-analogue, the complex [Cu(L(2))2Cl][CuCl2], was synthesized by the reaction between , CuCl2 and CuCl in a 2 : 1 : 1 molar ratio in MeCN. The ligand acts as a chelating one. In the structures of the complexes [Cu(L(2))2Br]2[Cu2Br4] and [Cu(L(2))2Cl][CuCl2] the Cu(2+) ion is in the cationic part of the complex whereas the Cu(+) ion is located in the anionic part. The best way to synthesize the mixed-valence 1D coordination polymer [Cu2L(3)Br3]n is to react CuBr2 with in a 2 : 1 molar ratio in the MeCN/CHCl3 mixture on heating. In the structure of [Cu2L(3)Br3]n the ligand shows chelating/bridging tridentate coordination. This is the first example of the tridentate coordination of 4-(1H-pyrazol-1-yl)-6-R-pyrimidines. The striking difference between the coordination behavior of and (chelating bidentate vs. chelating/bridging coordination) is related with the possibility of rotation of the 6-phenoxy group around the C-O bond which makes the N(1) pyrimidine atom less sterically hindered, enabling it to participate in metal ion binding. Importantly, all copper ions in [Cu2L(3)Br3]n show similar tetrahedral environments, CuNBr3 and CuN2Br2, which is extremely rare for mixed-valence copper(i,ii) compounds. The ligands and show blue emission which is quenched upon their coordination to copper ions. The 1D coordination polymer [Cu2L(3)Br3]n shows high thermal stability and unusual solvent-occlusion properties. The role of the substituents favoring the formation of the mixed-valence copper(i,ii) complexes with 4-(1H-pyrazol-1-yl)-6-R

  10. Probing covalency in halogen bonds through donor K-edge X-ray absorption spectroscopy: polyhalides as coordination complexes.

    Science.gov (United States)

    Mustoe, Chantal L; Gunabalasingam, Mathusan; Yu, Darren; Patrick, Brian O; Kennepohl, Pierre

    2017-10-13

    The properties of halogen bonds (XBs) in solid-state I 2 X - and I 4 X - materials (where X = Cl, Br) are explored using donor K-edge X-ray absorption spectroscopy (XAS) to experimentally determine the degree of charge transfer in such XB interactions. The degree of covalency in these bonds is substantial, even in cases where significantly weaker secondary interactions are observed. These data, in concert with previous work in this area, suggests that certain halogen bonds have covalent contributions to bonding that are similar to, and even exceed, those observed in transition metal coordinate bonds. For this reason, we suggest that XB interactions of this type be denoted in a similar way to coordination bonds (X → Y) as opposed to using a representation that is the same as for significantly less covalent hydrogen bonds (XY).

  11. Synthesis and investigation of new heteronuclear [Zn-La] coordination compounds based on unsaturated lanthanum complex with N,N'-tetraethyl-N''-trichloacetylphosphortriamide

    International Nuclear Information System (INIS)

    Amyirkhanov, O.V.; Sliva, T.Yu.; Moroz, O.V.; Trush, Je.A.; Frits'kij, Yi.O.

    2011-01-01

    New heteronuclear [Zn-La] coordination compounds, perspective luminescent materials, with general formulas [Zn(Ve)La(X) 2 (Ac)] ({Zn-La;Ve;X}) and [Zn(Vp)La(X) 2 (Ac)] ({Zn-La;Vp;X}) have been synthesized HX=CCl 3 C(O)NHP(O)[N(C 2 H 5 ) 2 ] 2 - N,N'-tetraethyl-N''-trichloracetylphosphortriamide, H 2 Ve and H 2 Vp are products of the condensation of 1,2-diaminoethane and 1,3-diaminopropane with o-vanillin, respectively). The composition of [Zn-La] complexes has been determined, and the coordination mode of a phosphorylated ligand has been suggested by element analysis, IR- and 1 H, 31 P NMR-spectroscopy.

  12. A comparison of early learning curves for complex bimanual coordination with open, laparoscopic, and flexible endoscopic instrumentation.

    Science.gov (United States)

    Spaun, Georg O; Zheng, Bin; Martinec, Daniel V; Arnold, Brittany N; Swanström, Lee L

    2010-09-01

    This study takes an initial step towards understanding the learning process of flexible endoscopic surgery. Bimanual coordination learning curves were contrasted between three different surgical paradigms. We hypothesized that use of an open or laparoscopic paradigm would result in better performance and a shorter learning process (reaching a learning plateau earlier) than an endoscopic paradigm. Our model required seven subjects to perform identical bimanual coordination tasks with three different tools (a dual-channel endoscope with graspers, laparoscopic Maryland graspers, and straight hemostats for open surgery). The task required subjects to coordinate two instruments in order to perform a series of standardized maneuvers. Performance was measured by movement speed and accuracy. The learning process was broken down into three distinct phases: the practice phase, the short-term retention phase, and the long-term retention phase. The learning curves of four surgical novices for 33 tasks with each device were compared with the performance of three surgeons. Overall performance speed was significantly faster using open or laparoscopic tools than endoscopy for all groups (open 13 ± 1 s; lap 28 ± 3 s; endo 202 ± 82 s; P learn using an open surgery paradigm. Performance times and the learning process take longer for the laparoscopic paradigm and significantly longer for the endoscopic paradigm.

  13. Synthesis, structure, and photoluminescence of ZnII and CdII coordination complexes constructed by structurally related 5,6-substituted pyrazine-2,3-dicarboxylate ligands

    Science.gov (United States)

    Li, Yun-Wu; Tao, Ying; Hu, Tong-Liang

    2012-08-01

    Aiming at exploring the effect of substituting groups of three structurally related ligands, 5,6-diethyl-pyrazine-2,3-dicarboxylic acid (H2L1), 5,6-diphenyl-pyrazine-2,3-dicarboxylic acid (H2L2), and dibenzo[f,h]quinoxaline-2,3-dicarboxylic acid (H2L3), seven new coordination polymers constructed from these three substituted dicarboxylate ligands, {[Zn(L1)(H2O)3]·2H2O}∞ (1), {[Cd2(L2ʹ)4(H2O)]·3H2O}∞ (2), [Zn(L2)(CH3OH)]∞ (3), {[Zn(L2)(H2O)2]·H2O}∞ (4), {[Zn(L2ʹ)]·H2O}∞ (5), [Zn2(L3)(DMF)4]∞(6), [Zn(L3)(2,2ʹ-bipy)(H2O)]∞(7), have been prepared and structurally characterized. 1 is a 1D chain structure in which ZnII ion is six-coordinated with octahedron geometry. 2 is also a 1D chain structure in which there are two crystallographically independent CdII ions in the asymmetric unit and exist transformative L2ʹ ligands in the resulting complex. 3 and 4 both possess 2D layer network with the same (4, 82) topology, while the two complexes take different coordination modes during the forming of the compounds. 5 has a 1D chain structure based on the transformative L2ʹ ligand in which ZnII ion is five-coordinated with bipyramidal geometry. 6 and 7 both have 1D chain structure constructed from L3 ligand. Thereinto, ZnII ion in 6 is five-coordinated by three oxygen atoms from two individual L3 ligands and two oxygen atoms from two DMF molecules. While in 7 there are also five coordination sites occupied by two carboxylate oxygen atoms from two L3 ligands. In addition, the compounds are characterized by elemental analysis, IR spectra. The luminescent properties of the compounds are also discussed and exhibit strong fluorescent emissions in the solid state.

  14. Hydrophosphorylation of 1,3-diphenyl-2-propen-1-one and 1-methyl-3-phenyl-2-propen-1-one in the coordination sphere of carbonyl complexes of group 6B metals

    International Nuclear Information System (INIS)

    Kuramshin, A.I.; Karpenko, E.A.; Cherkasov, R.A.

    2001-01-01

    Methods of synthesis of η 2 - and η 4 - complexes of chalcone and benzalacetone with hexacarbonyl mononuclear complexes of group 6B metals (M Cr, Mo, W) were developed and conditions of selective η 2 - or η 4 - coordination of π-heterodiene ligand were ascertained. By the method of IR and NMR spectroscopy it was shown that hydrophosphorylation of the complexes prepared occurs in the metal coordination sphere by the Abramov reaction scheme resulting in the relevant η 2 -coordinated α-hydroxyphosphonates. According to data of quantum-chemical calculations heterodienes lose planarity as a result of π-coordination with metal, which explains regioselectivity of phosphorylation by more electrophilic carbonyl group of coordinated enone [ru

  15. Zirconium and hafnium complexes containing N-alkyl substituted amine biphenolate ligands: coordination chemistry and living ring-opening polymerization catalysis.

    Science.gov (United States)

    Liang, Lan-Chang; Lin, Sheng-Ta; Chien, Chia-Cheng; Chen, Ming-Tsz

    2013-07-07

    The coordination chemistry of zirconium and hafnium complexes containing the tridentate amine biphenolate ligands [RN(CH2-2-O-3,5-C6H2(tBu)2)2](2-) ([R-ONO](2-); R = tBu (1a), iPr (1b), nPr (1c)) featuring distinct N-alkyl substituents is described. Alcoholysis of Zr(OiPr)4(HOiPr) or Hf(OiPr)4(HOiPr) with H2[1a] in diethyl ether solutions at -35 °C generates the corresponding five-coordinate [1a]M(OiPr)2 (M = Zr (2a), Hf (3a)) in high isolated yield. Similar reactions employing H2[1b] produce six-coordinate [1b]M(OiPr)2(HOiPr) (M = Zr (2b·HOiPr), Hf (3b·HOiPr)) as an isopropanol adduct. Repetitive trituration of 2b·HOiPr and 3b·HOiPr with diethyl ether gives five-coordinate 2b and 3b, respectively. Treatment of M(OiPr)4(HOiPr) with H2[1c] under similar conditions affords six-coordinate [1c]M(OiPr)2(HOiPr) (M = Zr (2c·HOiPr), Hf (3c·HOiPr)), subsequent recrystallization of which from acetonitrile-diethyl ether solutions leads to acetonitrile adducts 2c·MeCN and 3c·MeCN. Reactivity studies of these zirconium and hafnium complexes revealed that they are all active catalysts for ring-opening polymerization of ε-caprolactone. Among them, the N-isopropyl derived complexes are most reactive. Polymerizations catalyzed by 2b, 3b and 3c·MeCN were proved to be living. The X-ray structures of 2a·HOiPr, 2a·MeCN, 2c·HOiPr, 2c·MeCN, and 3c·MeCN are presented.

  16. Coordinating the Complexity of Tools, Tasks, and Users: On Theory-Based Approaches to Authoring Tool Usability

    Science.gov (United States)

    Murray, Tom

    2016-01-01

    Intelligent Tutoring Systems authoring tools are highly complex educational software applications used to produce highly complex software applications (i.e. ITSs). How should our assumptions about the target users (authors) impact the design of authoring tools? In this article I first reflect on the factors leading to my original 1999 article on…

  17. Synthesis, spectroscopic, coordination and biological activities of some transition metal complexes containing ONO tridentate Schiff base ligand.

    Science.gov (United States)

    Belal, A A M; El-Deen, I M; Farid, N Y; Zakaria, Rosan; Refat, Moamen S

    2015-01-01

    The main target of this paper is to get an interesting data for the preparation and characterizations of metal oxide (MO) nanoparticles using H2L Schiff base complexes as precursors through the thermal decomposition procedure. Five Schiff base complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions were synthesized from 2-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-benzoic acid new adduct (H2L). Theses complexes were characterized using infrared, electronic, mass and (1)H NMR spectroscopic techniques. The elemental analysis data was confirmed that the stoichiometry of (metal:H2L) is 1:1 molar ratio. The molar conductance indicates that all of complexes are non electrolytic. The general chemical formulas of these complexes is [M(L)(NH3)]·nH2O. All complexes are tetrahedral geometry. The thermal decomposition behavior of H2L hydrated and anhydrous complexes has been discussed using thermogravimetric analysis (TG/DTG) and differential thermal analyses (DTA) under nitrogen atmosphere. The crystalline phases of the reaction products were checked using X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Copyright © 2015 Elsevier B.V. All rights reserved.

  18. 4th July 2011 - Russian Deputy Director-General Director of Directorate for Scientific and Technical Complex ROSATOM V. Pershukov in the ATLAS underground experimental area with Adviser T. Kurtyka, ATLAS Technical Coordinator M. Nessi and ATLAS Russian users.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    4th July 2011 - Russian Deputy Director-General Director of Directorate for Scientific and Technical Complex ROSATOM V. Pershukov in the ATLAS underground experimental area with Adviser T. Kurtyka, ATLAS Technical Coordinator M. Nessi and ATLAS Russian users.

  19. 3-Methylindole-Based Tripodal Tetraphosphine Ruthenium Complexes in N2 Coordination and Reduction and Formic Acid Dehydrogenation

    NARCIS (Netherlands)

    van de Watering, F.F.; Heijtbrink, N.; van der Vlugt, J.I.; Dzik, W.I.; de Bruin, B.; Reek, J.N.H.

    2017-01-01

    The ruthenium(II) complexes RuCl2L1H, RuCl2L1CF3, RuCl2L1OMe and RuCl2L2H were synthesized from [Ru(η6-benzene)Cl(μ-Cl)]2 and the corresponding tripodal tris-3-methylindolephosphine-based ligands L1H, L1CF3, L1OMe, and L2H. Stoichiometric reduction of these complexes with KC8 yielded the

  20. Second-sphere coordination complex via hydrogen bonding: Synthesis, characterization, X-ray crystal structure determination and packing of hexaamminecobalt(III) chloride di( para-nitrobenzoate)

    Science.gov (United States)

    Sharma, Raj Pal; Bala, Ritu; Sharma, Rajni; Perez, Julio; Miguel, Daniel

    2006-09-01

    A reddish orange coloured crystalline solid of hexaamminecobalt(III) chloride di( para-nitrobenzoate) was obtained when hexaamminecobalt(III) chloride was reacted with the sodium salt of para-nitrobenzoic acid (1:3 molar ratio) in hot aqueous medium. This cobalt(III) complex salt has been characterized by elemental analyses and spectroscopic techniques (e.g. UV/visible, IR and NMR). Single-crystal X-ray structure determination of the title complex salt revealed that it contains the cationic cobaltammine ([Co(NH 3) 6] 3+) and mixed anions (Cl -, NO 2C 6H 4COO -), which are held together by electrostatic forces attractions through second-sphere coordination, i.e. N-H⋯O (carboxylate and nitro) and N-H⋯Cl hydrogen bonds, resulting in a three-dimensional network.

  1. Synthesis, photophysical properties, and computational studies of four-coordinate copper(I) complexes based on benzimidazolylidene N-heterocyclic carbene (NHC) ligands bearing aryl substituents

    Science.gov (United States)

    Xu, Shengxian; Wang, Jinglan; Liu, Shaobo; Zhao, Feng; Xia, Hongying; Wang, Yibo

    2018-02-01

    Three four-coordinate N-heterocyclic carbene (NHC) copper(I) complexes, [Cu(Ph-BenIm-Py)(POP)]PF6 (1), [Cu(Naph-BenIm-Py)(POP)]PF6 (2), and [Cu(Anthr-BenIm-Py)(POP)]PF6 (3) (Ph-BenIm-Py = 3-benzyl-1-(pyridin-2-yl)-1H-benzimidazolylidene, Naph-BenIm-Py = 3-(naphthalen-2-yl-1-(pyridin-2-yl)-1H- benzimidazolylidene, Anthr-BenIm-Py = 3-(anthracen-9-yl)-1-(pyridin-2-yl)-1H-benzimidazolylidene, and POP = bis[2-diphenylphosphino]-phenyl)ether) have been synthesized and characterized. The different aryl substituents (phenyl, naphthyl, and anthracyl groups) were introduced into NHC ligands and the corresponding photophysical properties of the complexes were systematically investigated. The absorption spectra of all NHCsbnd Cu(I) complexes show a characteristic feature of metal-to-ligand charge transfer (MLCT) in the lower-energy region. Complex 1 exhibited good photoluminescence (PL) properties companying with the high quantum yields and long excited-state lifetimes, whereas 2 and 3 with naphthyl and anthracyl groups show the low PL efficiency caused by the strong π-π stacking interactions. Density functional theory (DFT) and time dependent density functional theory (TDDFT) calculations were employed to rationalize the photophysical properties of the NHCsbnd Cu(I) complexes.

  2. Five-Coordinate Zinc(II Complex: Synthesis, Characterization, Molecular Structure, and Antibacterial Activities of Bis-[(E-2-hydroxy-N′-{1-(4-methoxyphenylethylidene}benzohydrazido]dimethylsulfoxidezinc(II Complex

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Liu

    2017-01-01

    Full Text Available The titled Zn(II complex was synthesized by reacting the compound (E-2-hydroxy-N′-{1-(4-methoxyphenylethylidene}benzohydrazide with zinc(II acetate dihydrate in alkaline DMSO and ethanol solution under reflux condition for 28 hours. The resulting solid was filtered and recrystallized from the mixture of ethanol and DMSO. The hydrazone Schiff base and its Zn(II complex were characterized using 1H, 13C NMR, FTIR, UV-Vis spectroscopy, and single crystal X-ray diffraction analysis. Meanwhile, their antibacterial activities were examined using disc diffusion method. The spectral studies showed that the hydrazone Schiff base underwent keto-enol tautomerization, forming a bidentate ligand (N,O towards Zn(II ion. Surprisingly, on top of the two hydrazone Schiff base molecules which coordinated to the Zn metal center, an additional DMSO molecule was found attached to the Zn metal center in the crystal data, resulting in a 5-coordinate distorted trigonal bipyramidal Zn(II complex. Both hydrazone Schiff base and its Zn(II complexes were found to exhibit low antibacterial activity even when the concentrations were increased to 800 ppm.

  3. Novel bipyridinyl oxadiazole-based metal coordination complexes: High efficient and green synthesis of 3,4-dihydropyrimidin-2(1H)-ones through the Biginelli reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin-Hua; Zhang, E. [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Tang, Gui-Mei, E-mail: meiguit@163.com [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Wang, Yong-Tao, E-mail: ceswyt@qlu.edu.cn [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Cui, Yue-Zhi [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Ng, Seik Weng [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2016-09-15

    Three new metal coordination complexes, namely, [Co(BPO){sub 2}(H{sub 2}O){sub 4}](BS){sub 2}(H{sub 2}O){sub 2} (1), [Co(BPO){sub 2}(H{sub 2}O){sub 4}](ABS){sub 2}(H{sub 2}O){sub 2} (2), [Co(BPO){sub 2}(H{sub 2}O){sub 4}](MBS){sub 2}(H{sub 2}O){sub 2} (3) [BPO=2,5-di(pyridin-4-yl)-1,3,4-oxadiazole, BS=benzenesulphonate, ABS=4-aminobenzenesulphonate, MBS=4-methylbenzenesulphonate] were obtained under hydrothermal conditions. Complexes 1–3 were structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR and thermogravimetric analyses (TGA). All of them display a zero-dimensional motif, in which strong intermolecular hydrogen bonding interactions (O–H···O/N) and packing interactions (C–H···π and π···π) make them achieve a three-dimensional supramolecular architecture. The primary catalytic results of these three complexes show that high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones was observed under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time. - Graphical abstract: Three new metal coordination complexes with bipyridinyl-oxadiazole were obtained under hydrothermal conditions, which display a zero-dimensional motif, and show high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time. Display Omitted.

  4. Large-eddy simulation study of turbulent flow over a complex topography using the terrain-following coordinate transformation method: application to aeolian dunes

    Science.gov (United States)

    Yang, Jianzhi; Anderson, William

    2017-11-01

    Modeling of turbulent flow over complex topography is of great interest in many engineering applications. However, accurate modeling of turbulent flow over complex topography still presents major technical challenges. The immersed boundary method (IBM) has been widely used to deal with the arbitrary domain geometry, due to its advantage of keeping the computation grid and, thus, preservation of the original numerical formulation. But IBM can introduce wall-modeling errors since the terrain and computational mesh points are not collocated. Terrain-following coordinate transformation, however, obviates wall-modeling errors. In this study, an existing large-eddy simulation (LES) code has been generalized for coordination transformation in the wall-normal direction, and applied to flow over a series of topographic configurations (flat surface, as a baseline for comparison, spanwise ridge, and an aeolian dune digital elevation map). Validation of simulation data has, firstly, been performed via comparison with first- and second-order data experimental data. Secondly, for the three-dimensional hill and dune cases, an LES simulation with IBM will be also performed. The implications of these results for physics-based, aeolian morphodynamic modeling will be discussed.

  5. Extending the NIF DISCO framework to automate complex workflow: coordinating the harvest and integration of data from diverse neuroscience information resources.

    Science.gov (United States)

    Marenco, Luis N; Wang, Rixin; Bandrowski, Anita E; Grethe, Jeffrey S; Shepherd, Gordon M; Miller, Perry L

    2014-01-01

    This paper describes how DISCO, the data aggregator that supports the Neuroscience Information Framework (NIF), has been extended to play a central role in automating the complex workflow required to support and coordinate the NIF's data integration capabilities. The NIF is an NIH Neuroscience Blueprint initiative designed to help researchers access the wealth of data related to the neurosciences available via the Internet. A central component is the NIF Federation, a searchable database that currently contains data from 231 data and information resources regularly harvested, updated, and warehoused in the DISCO system. In the past several years, DISCO has greatly extended its functionality and has evolved to play a central role in automating the complex, ongoing process of harvesting, validating, integrating, and displaying neuroscience data from a growing set of participating resources. This paper provides an overview of DISCO's current capabilities and discusses a number of the challenges and future directions related to the process of coordinating the integration of neuroscience data within the NIF Federation.

  6. Extending the NIF DISCO framework to automate complex workflow: coordinating the harvest and integration of data from diverse neuroscience information resources

    Science.gov (United States)

    Marenco, Luis N.; Wang, Rixin; Bandrowski, Anita E.; Grethe, Jeffrey S.; Shepherd, Gordon M.; Miller, Perry L.

    2014-01-01

    This paper describes how DISCO, the data aggregator that supports the Neuroscience Information Framework (NIF), has been extended to play a central role in automating the complex workflow required to support and coordinate the NIF’s data integration capabilities. The NIF is an NIH Neuroscience Blueprint initiative designed to help researchers access the wealth of data related to the neurosciences available via the Internet. A central component is the NIF Federation, a searchable database that currently contains data from 231 data and information resources regularly harvested, updated, and warehoused in the DISCO system. In the past several years, DISCO has greatly extended its functionality and has evolved to play a central role in automating the complex, ongoing process of harvesting, validating, integrating, and displaying neuroscience data from a growing set of participating resources. This paper provides an overview of DISCO’s current capabilities and discusses a number of the challenges and future directions related to the process of coordinating the integration of neuroscience data within the NIF Federation. PMID:25018728

  7. Studies on coordination chemistry and bioactivity of complexes of a tridentate ONS Schiff base with some heavier transition metal ions

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Tan Mei Lin; Ali, A.M.

    2003-09-01

    A tridentate Schiff base, S-benzyl-β-N-(2-hydroxyphenyl)methylenedithiocarbazate, (HONSH), with a donor sequence of ONS, was synthesized from the condensation of S-benzyldithiocarbazate (SBDTC) with an equimolar amount of 2-hydroxybenzaldehyde in absolute ethanol. The reactions of HONSH with metal ions [La(III), Ce(IV) and Th(IV)] yielded complexes of compositions, [La(ONS)NO 3 .2H 2 O], [Ce(ONS)(NO 3 ) 2 ] and [Th(ONS) 2 ]. The ligands and the complexes were characterized from elemental analyses and spectroscopic measurements. The metal complexes were found to be active against colon cancer cell lines with the CD 50 values of 27.5, 28.4 and 19.3 μg/ml for the La(III), Ce(FV) and Th(IV) complexes, respectively. The La(IH) complex was found to be very active against leukemic cell lines with the CD 50 value of 6.8 μg/ml. (author)

  8. Molybdenum complexes of biochemical interest. New coordination complexes of oxomolybdenum(V) with the tridentate ONO donor Schiff bases derived from salicylaldehydes and ethanolamine

    Energy Technology Data Exchange (ETDEWEB)

    Syamal, A.; Niazi, M.A.B.

    1985-02-01

    New oxomolybdenum(V) complexes MoOClL (where LH/sub 2/ = Schiff base) derived from ethanolamine and salicylaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 5-nitrosalicylaldehyde, 3-ethoxysalicylaldehyde and 2-hydroxy-1-naphthaldehyde have been synthesized and characterised by elemental analyses, conductance, molecular weight, I.R. and electronic spectra and magnetic measurements. The Schiff bases behave as dibasic tridentate ONO donor ligands. The complexes are non-electrolytes and dimers. The complexes exhibit subnormal magnetic moments and are involved in antiferromagnetic exchange with S = 0 ground state. The complexes exhibit electronic spectral bands at ca. 13000 and ca. 17000 cm/sup -1/ due to the transitions dsub(xy)- > dsub(xz,yz) (/sup 2/B/sub 2/- > /sup 2/E) and dsub(xy)- > dsub(x2-y2) (/sup 2/B/sub 2/- > /sup 2/B/sub 1/), respectively. The ..nu..(Mo = O) frequency of the complexes is observed in the 900-970 cm/sup -1/ region. On the basis of the magnetic susceptibility, I.R. and molecular weight data a dimetallic structure with alcoholic oxygen atoms as the bridging atoms is suggested.

  9. Coordination chemistry of actinide elements: preparation of new uranium complexes with schiff bases and their characterization (Preprint No. CT-31)

    International Nuclear Information System (INIS)

    Hingorani, S.; Reddy, P.S.N.; Agarwala, B.V.

    1988-02-01

    The Schiff bases, o-vanillin semicarbazone (oVSC) and 2-pyridine carboxaldehyde isonicotinoyl hydrazone (PCINH) have been prepared and their novel complexes with dioxouranium(VI) have been synthesized and characterized by IR spectra, elemental analysis and other physico-chemical techniques. (author)

  10. Structural Reassessment of [W(CO)(5)(TCNE)]: N (sigma) Coordination Instead of an Olefin (pi) Complex

    Czech Academy of Sciences Publication Activity Database

    Bubrin, M.; Krafft, M. J.; Steudle, L.; Hübner, R.; Field, J. S.; Záliš, Stanislav; Kaim, W.

    2012-01-01

    Roč. 31, č. 17 (2012), s. 6305-6311 ISSN 0276-7333 R&D Projects: GA MŠk LD11086 Institutional support: RVO:61388955 Keywords : TRANSFER-CATALYZED SUBSTITUTION * CARBONYL-COMPLEXES * CHARGE-TRANSFER Subject RIV: CG - Electrochemistry Impact factor: 4.145, year: 2012

  11. Fivefold Coordination of a CuII–Aqua Ion,[Cu(H2O)5]2+ Complex ...

    Indian Academy of Sciences (India)

    It is generally assumed that a CuII ion in an aqueous solution forms an octahedral [Cu(H2O)6]2+ complex that undergoes Jahn–Teller distortion with elongated axial bonds because of its d9 electronic configuration.

  12. New in situ generated acylhydrazidate-coordinated complexes and acylhydrazide molecules: Synthesis, structural characterization and photoluminescence property

    Science.gov (United States)

    Wang, Yan-Ning; Huo, Qi-Sheng; Zhang, Ping; Yu, Jie-Hui; Xu, Ji-Qing

    2016-10-01

    By utilizing the hydrothermal in situ acylation of organic acids with N2H4, three acylhydrazidate-coordinated compounds [Mn(L1)2(H2O)2] (L1 = 2,3-quinolinedicarboxylhydrazidate; HL1 = 2,3-dihydropyridazino[4,5-b] quinoline-1,4-dione) 1, [Mn2(ox)(L2)2(H2O)6]·2H2O (L2 = benzimidazolate-5,6-dicarboxylhydrazide; HL2 = 6,7-dihydro-1H-imidazo[4,5-g]phthalazine-5,8-dione; ox = oxalate) 2, and [Cd(HL3)(bpy)] (L3 = 4,5-di(3‧-carboxylphenyl)phthalhydrazidate; H3L3 = 6,7-dihydro-1H-imidazo[4,5-g]phthalazine-5,8-dione; bpy = 2,2‧-bipyridine) 3, as well as two acylhydrazide molecules L4 (L4 = oxepino[2,3,4-de:7,6,5-d‧e‧]diphthalazine-4,10(5H,9H)-dione) 4 and L5 (L5 = 4,5-dibromophthalhydrazide; L5 = 6,7-dibromo-2,3-dihydrophthalazine-1,4-dione) 5 were obtained. X-ray single-crystal diffraction analysis reveals that (i) 1 only possesses a mononuclear structure, but it self-assembles into a 2-D supramolecular network via the Nhydrazinesbnd H ⋯ Nhydrazine and Owsbnd H ⋯ Ohydroxylimino interactions; (ii) 2 exhibits a dinuclear structure. Ox acts as the linker, while L2 just serves as a terminal ligand; (iii) In 3, L3 acts as a 3-connected node to propagate the 7-coordinated Cd2 + centers into a 1-D double-chain structure; (iv) 4 is a special acylhydrazide molecule. Two sbnd OH groups for the intermediates 3,3‧-biphthalhydrazide further lose one water molecule to form 4; (v) 5 is a common monoacylhydrazide molecule. Via the Nhydrazinesbnd H ⋯ Ohydrazine, Ohydroxyliminosbnd H ⋯ Oacylamino and the π ⋯ π interactions, it self-assembles into a 2-D supramolecular network. The photoluminescence analysis reveals that 4 emits light with the maxima at 510 nm.

  13. Characterization of the TolB-Pal trans-envelope complex from Xylella fastidiosa reveals a dynamic and coordinated protein expression profile during the biofilm development process.

    Science.gov (United States)

    Santos, Clelton A; Janissen, Richard; Toledo, Marcelo A S; Beloti, Lilian L; Azzoni, Adriano R; Cotta, Monica A; Souza, Anete P

    2015-10-01

    The intriguing roles of the bacterial Tol-Pal trans-envelope protein complex range from maintenance of cell envelope integrity to potential participation in the process of cell division. In this study, we report the characterization of the XfTolB and XfPal proteins of the Tol-Pal complex of Xylella fastidiosa. X. fastidiosa is a major plant pathogen that forms biofilms inside xylem vessels, triggering the development of diseases in important cultivable plants around the word. Based on functional complementation experiments in Escherichia coli tolB and pal mutant strains, we confirmed the role of xftolB and xfpal in outer membrane integrity. In addition, we observed a dynamic and coordinated protein expression profile during the X. fastidiosa biofilm development process. Using small-angle X-ray scattering (SAXS), the low-resolution structure of the isolated XfTolB-XfPal complex in solution was solved for the first time. Finally, the localization of the XfTolB and XfPal polar ends was visualized via immunofluorescence labeling in vivo during bacterial cell growth. Our results highlight the major role of the components of the cell envelope, particularly the TolB-Pal complex, during the different phases of bacterial biofilm development. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Case Management for Patients with Complex Multimorbidity: Development and Validation of a Coordinated Intervention between Primary and Hospital Care

    Directory of Open Access Journals (Sweden)

    Salvador Tortajada

    2017-06-01

    Full Text Available In the past few years, healthcare systems have been facing a growing demand related to the high prevalence of chronic diseases. Case management programs have emerged as an integrated care approach for the management of chronic disease. Nevertheless, there is little scientific evidence on the impact of using a case management program for patients with complex multimorbidity regarding hospital resource utilisation.  We evaluated an integrated case management intervention set up by community-based care at outpatient clinics with nurse case managers from a telemedicine unit. The hypothesis to be tested was whether improved continuity of care resulting from the integration of community-based and hospital services reduced the use of hospital resources amongst patients with complex multimorbidity.  A retrospective cohort study was performed using a sample of 714 adult patients admitted to the program between January 2012 and January 2015. We found a significant decrease in the number of emergency room visits, unplanned hospitalizations, and length of stay, and an expected increase in the home care hospital-based episodes. These results support the hypothesis that case management interventions can reduce the use of unplanned hospital admissions when applied to patients with complex multimorbidity.

  15. Managing interteam coordination within and between organizations

    NARCIS (Netherlands)

    de Vries, Thomas Arend

    2015-01-01

    To accomplish complex tasks and effectively respond to environmental contingencies, teams must coordinate task-related issues with other teams (i.e., interteam coordination). Regrettably, interteam coordination is often complicated by misunderstandings that can arise from differences in teams’

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

    Czech Academy of Sciences Publication Activity Database

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

    2017-01-01

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

  17. Scandium and yttrium metallocene borohydride complexes: comparisons of (BH4)1- vs. (BPh4)1- coordination and reactivity.

    Science.gov (United States)

    Demir, Selvan; Siladke, Nathan A; Ziller, Joseph W; Evans, William J

    2012-08-28

    The synthetically accessible borohydride complexes (C(5)Me(4)H)(2)Ln(THF)(BH(4)) and (C(5)Me(5))(2)Ln(THF)(BH(4)) (Ln = Sc, Y) were examined as precursors alternative to the heavily-used tetraphenylborate analogs, [(C(5)Me(4)H)(2)Ln][BPh(4)] and [(C(5)Me(5))(2)Ln][BPh(4)], employed in LnA(2)A'/M reduction reactions (A = anion; M = alkali metal) that generate "LnA(2)" reactivity and form reduced dinitrogen complexes [(C(5)R(5))(2)(THF)(x)Ln](2)(μ-η(2):η(2)-N(2)) (x = 0, 1). The crystal structures of the yttrium borohydrides, (C(5)Me(4)H)(2)Y(THF)(μ-H)(3)BH, 1, and (C(5)Me(5))(2)Y(THF)(μ-H)(2)BH(2), 2, were determined for comparison with those of the yttrium tetraphenylborates, [(C(5)Me(4)H)(2)Y][(μ-Ph)(2)BPh(2)], 3, and [(C(5)Me(5))(2)Y][(μ-Ph)(2)BPh(2)], 4. The complex (C(5)Me(4)H)(2)Sc(μ-H)(2)BH(2), 5, was synthesized and structurally characterized for comparison with (C(5)Me(5))(2)Sc(μ-H)(2)BH(2), 6, [(C(5)Me(4)H)(2)Sc][(μ-Ph)BPh(3)], 7, and [(C(5)Me(5))(2)Sc][(μ-Ph)BPh(3)], 8. Structural information was also obtained on the borohydride derivatives, (C(5)Me(4)H)(2)Sc(μ-H)(2)BC(8)H(14), 9, and (C(5)Me(5))(2)Sc(μ-H)(2)BC(8)H(14), 10, obtained from 9-borabicyclo(3.3.1)nonane (9-BBN) and (C(5)Me(4)R)(2)Sc(η(3)-C(3)H(5)), where R = H, 11; Me, 12. The preference of the metals for borohydride over tetraphenylborate binding was shown by the facile displacement of (BPh(4))(1-) in 3, 4, 7, and 8 by (BH(4))(1-) to make the respective borohydride complexes 1, 2, 5, and 6. These results are consistent with the fact that the borohydrides are not as useful as precursors in A(2)LnA'/M reductions of N(2). An unusual structural isomer of [(C(5)Me(4)H)(2)Sc](2)(μ-η(2):η(2)-N(2)), 13', was isolated from this study that shows the variations in ligand orientation that can occur in the solid state.

  18. Fac and mer isomers of Ru(II) tris(pyrazolyl-pyridine) complexes as models for the vertices of coordination cages: structural characterisation and hydrogen-bonding characteristics.

    Science.gov (United States)

    Metherell, Alexander J; Cullen, William; Stephenson, Andrew; Hunter, Christopher A; Ward, Michael D

    2014-01-07

    We have prepared a series of mononuclear fac and mer isomers of Ru(II) complexes containing chelating pyrazolyl-pyridine ligands, to examine their differing ability to act as hydrogen-bond donors in MeCN. This was prompted by our earlier observation that octanuclear cube-like coordination cages that contain these types of metal vertex can bind guests such as isoquinoline-N-oxide (K = 2100 M(-1) in MeCN), with a significant contribution to binding being a hydrogen-bonding interaction between the electron-rich atom of the guest and a hydrogen-bond donor site on the internal surface of the cage formed by a convergent set of CH2 protons close to a 2+ metal centre. Starting with [Ru(L(H))3](2+) [L(H) = 3-(2-pyridyl)-1H-pyrazole] the geometric isomers were separated by virtue of the fact that the fac isomer forms a Cu(I) adduct which the mer isomer does not. Alkylation of the pyrazolyl NH group with methyl iodide or benzyl bromide afforded [Ru(L(Me))3](2+) and [Ru(L(bz))3](2+) respectively, each as their fac and mer isomers; all were structurally characterised. In the fac isomers the convergent group of pendant -CH2R or -CH3 protons defines a hydrogen-bond donor pocket; in the mer isomer these protons do not converge and any hydrogen-bonding involving these protons is expected to be weaker. For both [Ru(L(Me))3](2+) and [Ru(L(bz))3](2+), NMR titrations with isoquinoline-N-oxide in MeCN revealed weak 1 : 1 binding (K ≈ 1 M(-1)) between the guest and the fac isomer of the complex that was absent with the mer isomer, confirming a difference in the hydrogen-bond donor capabilities of these complexes associated with their differing geometries. The weak binding compared to the cage however occurs because of competition from the anions, which are free to form ion-pairs with the mononuclear complex cations in a way that does not happen in the cage complexes. We conclude that (i) the presence of fac tris-chelate sites in the cage to act as hydrogen-bond donors, and (ii

  19. NF-Y and the immune response: Dissecting the complex regulation of MHC genes.

    Science.gov (United States)

    Sachini, Nikoleta; Papamatheakis, Joseph

    2017-05-01

    Nuclear Factor Y (NF-Y) was first described as one of the CCAAT binding factors. Although CCAAT motifs were found to be present in various genes, NF-Y attracted a lot of interest early on, due to its role in Major Histocompatibility Complex (MHC) gene regulation. MHC genes are crucial in immune response and show peculiar expression patterns. Among other conserved elements on MHC promoters, an NF-Y binding CCAAT box was found to contribute to MHC transcriptional regulation. NF-Y along with other DNA binding factors assembles in a stereospecific manner to form a multiprotein scaffold, the MHC enhanceosome, which is necessary but not sufficient to drive transcription. Transcriptional activation is achieved by the recruitment of yet another factor, the class II transcriptional activator (CIITA). In this review, we briefly discuss basic findings on MHCII transcription regulation and we highlight NF-Y different modes of function in MHCII gene activation. This article is part of a Special Issue entitled: Nuclear Factor Y in Development and Disease, edited by Prof. Roberto Mantovani. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Open coordination sites-induced structural diversity of a new series of Cu(II) complexes with tridentate aroylhydrazone Schiff base

    Science.gov (United States)

    Xu, Guohong; Tang, Beibei; Gu, Leilei; Zhou, Pei; Li, Hui

    2016-09-01

    Six Cu(II) complexes containing the NO2 donor tridentate asymmetrical aroylhydrazone ligand (E)-4-hydroxy-N‧-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide (HL), namely, [Cu(L)Cl]·2H2O (1), [Cu(L)(CH3OH)2]·NO3 (2), [Cu(L)(NO3)(H2O)]·H2O (3), [Cu(L)(CH3OH)Cl]·CH3OH (4), [Cu(L)(SCN)(DMF)]·DMF (5) and {[Cu(L)(4,4‧-bipy)]ClO4·4DMF}n (6) have been synthesized and analysized by X-ray singal crystal diffraction. The structures of 1-6 are varied from zero-dimensional (0D) mononuclear complex to one-dimensional (1D) polymer based on the control of solvents, anions or auxiliary ligands, which can occupy the open coordination sites of Cu(II). Different hydrogen bonding interactions can also be observed in these complexes.

  1. XRCC1 coordinates disparate responses and multiprotein repair complexes depending on the nature and context of the DNA damage

    DEFF Research Database (Denmark)

    Hanssen-Bauer, Audun; Solvang-Garten, Karin; Sundheim, Ottar

    2011-01-01

    . We demonstrate that the laser dose used for introducing DNA damage determines the repertoire of DNA repair proteins recruited. Furthermore, we demonstrate that recruitment of POLß and PNK to regions irradiated with low laser dose requires XRCC1 and that inhibition of PARylation by PARP......-inhibitors only slightly reduces the recruitment of XRCC1, PNK, or POLß to sites of DNA damage. Recruitment of PCNA and FEN-1 requires higher doses of irradiation and is enhanced by XRCC1, as well as by accumulation of PARP-1 at the site of DNA damage. These data improve our understanding of recruitment of BER......XRCC1 is a scaffold protein capable of interacting with several DNA repair proteins. Here we provide evidence for the presence of XRCC1 in different complexes of sizes from 200 to 1500 kDa, and we show that immunoprecipitates using XRCC1 as bait are capable of complete repair of AP sites via both...

  2. Bulk Coordination Polymerization of Dicyclopentadiene (DCPD) by Pd Complexes Containing β-Ketoiminate or β-Diketiminate Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eung Jun; Kim, Ho Sup; Lee, Byoung Ki; Lee, Ik Mo [Inha Univ., Incheon (Korea, Republic of); Hwang, Woon Sung; Sung, Ik Kyoung [Kolon Industries, Inc., Incheon (Korea, Republic of)

    2012-12-15

    Several palladium complexes containing β-ketoiminate and β-diketiminate ligands successfully produced poly(DCPD) possibly via vinyl addition. It was found that catalysts with β-diketiminate ligands containing bulkier aryl substituents showed the highest activity in the presence of MAO as a cocatalyst. Purity of DCPD is quite essential for the higher activity and small amount of organic solvent such as CH{sub 2}Cl{sub 2} and toluene is required to reduce the viscosity of the reactant mixture for the higher activity. {sup 1}H NMR spectra of produced polymers with N,N-dimethylanilinium tetra(pentafluorophenyl)borate (N,N-DAPFAr'{sub 4}) show that 5,6-double bond of DCPD is removed with 2,3-double bond remaining. Produced poly(DCPD) with MAO cocatalyst is quite rigid and insoluble in common organic solvents but rather brittle.

  3. Influence of the π-coordinated arene on the anticancer activity of ruthenium(II carbohydrate organometallic complexes

    Directory of Open Access Journals (Sweden)

    Muhammad eHanif

    2013-10-01

    Full Text Available The synthesis and in vitro cytotoxicity of a series of RuII(arene complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well with cellular accumulation. The most lipophilic compound bearing a biphenyl moiety and a cyclohexylidene-protected carbohydrate is the most cytotoxic with unprecedented IC50 values for the compound class in three human cancer cell lines. This compound shows reactivity to the DNA model nucleobase 9-ethylguanine, but does not alter the secondary structure of plasmid DNA indicating that other biological targets are responsible for its cytotoxic effect.

  4. Brightly phosphorescent, environmentally responsive hydrogels containing a water-soluble three-coordinate gold(I) complex.

    Science.gov (United States)

    Marpu, Sreekar; Hu, Zhibing; Omary, Mohammad A

    2010-10-05

    Stimuli-responsive phosphorescent hydrogel microspheres have been synthesized by incorporating a water-soluble phosphorescent Au(I) complex, Na(8)[Au(TPPTS)(3)], TPPTS = tris(3,3',3''-trisulfonatophenyl)phosphine, into the polymer network of poly(N-isopropylacrylamide) (PNIPAM). Remarkable sensitization of the Au-centered emission takes place in the resulting phosphorescent hydrogels (by up to 2 orders of magnitude!) compared to that of the gold complex alone in pure water. Results of pH- and temperature-dependent luminescence titrations show that the sensitization is further magnified at physiological conditions, which is desirable for biomedical applications that will include bioimaging and drug delivery. The physical properties of PNIPAM microgels are not negatively impacted by the presence of the gold luminophore, as the colloidal crystallinity and phase transition properties remain intact. Phosphorescent microspheres have been further cross-linked by covalently bonding to neighboring particles, leading to brightly phosphorescent/high-water-content crystalline hydrogel networks with more stable crystallinity vs microgel soft crystals. These gel networks exhibit the same green phosphorescence seen in the hydrogel microspheres and pure Na(8)[Au(TPPTS)(3)] aqueous solutions with a broad unstructured profile and peak maximum at ∼525 nm. Dehydration leads to further emission sensitization and gradual blue shifts that can be fine-tuned to ultimately reach a turquoise emission at ∼490 nm in the freeze-dried form of the gel, corresponding to the emission of single crystals of Na(8)[Au(TPPTS)(3)], in agreement with the photoinduced Jahn-Teller distorted excited state model we reported earlier. Remarkable sensitivity to temperature and pH takes place in the emission enhancement with particularly favorable results at physiological conditions. The work herein represents a unique example of a stimulus-responsive phosphorescent hydrogel from a transition metal-based as

  5. 1H and 13C NMR coordination-induced shifts in a series of tris(α-diimine)ruthenium(II) complexes containing pyridine, pyrazine, and thiazole moieties

    International Nuclear Information System (INIS)

    Orellana, G.; Ibarra, C.A.; Santoro, J.

    1988-01-01

    1 H and 13 C NMR chemical shifts of a series of ruthenium(II) tris chelates containing the heterocyclic ligands 2,2'-bipyridine, 2-(2-pyridyl)thiazole, 2-(2-pyrazyl)thiazole, and 2,2'-bithiazole are reported and compared to those of the corresponding free ligands. Calculated coordination-induced shifts (CIS, δ complexed - δ free ) range from +0.41 to -1.00 ppM for 1 H and from +5.8 to -3.7 ppM for 13 C nuclei. These values are discussed on the basis of the various effects (charge perturbation and field interactions) that arise upon chelation: electronic σ-donation to the metallic center via the nitrogen lone pair, d-π* back-donation to the ligand, van der Waals interactions, and magnetic anisotropy of the spectator ligands. Semiquantitative values of each effect at the different positions have been proposed, taking theoretical calculations of steric and anisotropic contributions as the starting point. Shielding van der Waals interaction between proximate atoms influences only the H(3') CIS of six-membered moieties, but to a very low extent (<0.15 ppM). Magnetic anisotropy of proximate ring currents practically determines the CIS of the α positions for all the complexed ligands examined (upfield shifts from -0.8 to -1.0 ppm), has a lower influence on external β positions (< 0.2 ppM), and is negligible for γ-protons. σ-donation deshields all the positions, its contribution increasing as protons separate from the coordinated nitrogen atom (up to 0.4 ppM). Π-back-bonding is a weaker effect (< 0.2 ppM upfield contribution) that operates mainly on the γ position of the pyridine and α and β positions of the pyrazine rings. 36 refs., 3 figs., 4 tabs

  6. Coordination and reductive chemistry of tetraphenylborate complexes of trivalent rare earth metallocene cations, [(C5Me5)2Ln][(μ-Ph)2BPh2].

    Science.gov (United States)

    MacDonald, Matthew R; Ziller, Joseph W; Evans, William J

    2011-05-02

    The reactivity of the tetraphenylborate salts of the rare earth metallocene cations [(C(5)Me(5))(2)Ln][(μ-Ph)(2)BPh(2)] (Ln = Y, 1; Sm, 2) has been investigated with substrates that undergo reduction with f element complexes to probe metal-substrate interactions prior to reduction. Results with NaN(3), 1-adamantyl azide, acetone, benzophenone, phenanthroline, pyridine, azobenzene, and phenazine are described. Not only were coordination complexes isolated, but substrate reduction by (BPh(4))(-) was also observed. Complex 1 reacts with NaN(3) to form the azide [(C(5)Me(5))(2)YN(3)](x), 3, which crystallizes as [(C(5)Me(5))(2)Y(μ-N(3))](3), 4, when obtained from 1 and 1-adamantyl azide. The samarium analogue [(C(5)Me(5))(2)SmN(3)](x), 5, can be produced similarly from 2 and NaN(3) and crystallized from MeCN as [(C(5)Me(5))(2)Sm(NCMe)(μ-N(3))](3), 6, and {[(C(5)Me(5))(2)Sm(μ-N(3))][(C(5)Me(5))(2)Sm(NCMe)(μ-N(3))]}(n), 7. Complexes 1 and 2 react with stoichiometric amounts of acetone and benzophenone to form the ketone adducts [(C(5)Me(5))(2)Ln(OCMe(2))(2)][BPh(4)] (Ln = Y, 8; Sm, 9) and [(C(5)Me(5))(2)Ln(OCPh(2))(2)][BPh(4)] (Ln = Y, 10; Sm, 11), respectively. Phenanthroline (phen) coordinates to 1 to form [(C(5)Me(5))(2)Y(phen)][BPh(4)], 12. Complexes 1 and 2 react with pyridine (py) to form [(C(5)Me(5))(2)Ln(py)(2)][BPh(4)], (Ln = Y, 13; Sm, 14). Complexes 3, 8, 10, and 12 can also be made from the solvated cation [(C(5)Me(5))(2)Y(THF)(2)][BPh(4)]. The reaction of 1 with PhNNPh yields the diamagnetic adduct [(C(5)Me(5))(2)Y(PhNNPh)][BPh(4)], 15, which transforms in benzene to the radical anion complex (C(5)Me(5))(2)Y(PhNNPh), 16, via a one electron reduction by (BPh(4))(-). Complex 1 similarly reacts with phenazine (phz) to produce the first rare earth phenazine radical anion complex {[(C(5)Me(5))(2)Y](2)(phz)}{BPh(4)}, 17. Further reduction of phenazine by (BPh(4))(-) in 17 yields [(C(5)Me(5))(2)Y](2)(phz), 18, which contains the common (phz)(2-) dianion. The

  7. Glucose-lowering properties of vanadium compounds: comparison of coordination complexes with maltol or kojic acid as ligands.

    Science.gov (United States)

    Yuen, V G; Caravan, P; Gelmini, L; Glover, N; McNeill, J H; Setyawati, I A; Zhou, Y; Orvig, C

    1997-11-01

    Bis(kojato)oxovanadium(IV) [abbreviated VO(ka)2], a close chemical analog of the insulin-mimetic lead compound bis(maltolato)oxovanadium(IV)--abbreviated BMOV or VO(ma)2--is reported and its reaction chemistry and insulin-mimetic properties are presented. VO(ka)2 [log K1 = 7.61(10), log K2 = 6.89(6), log beta 2 = 14.50(16)] has a reaction chemistry which directly parallels that of VO(ma)2. In aqueous solution it is more slowly oxidized by molecular oxygen to [VO2(ka)2]- than is VO(ma)2 to [VO2(ma)2]-. Variable pH electrochemistry and variable pH 51V NMR of solutions of VO(ka)2 are presented and contrasted with the corresponding results for VO(ma)2. Time course studies (24 hr) in STZ-diabetic rats following the oral or i.p. administration of VO(ka)2, VO(ma)2, VO2+ (vanadyl) as vanadyl sulfate (VOSO4), and [VO2(ma)2]- as its [NH4]+ salt have been performed, as have chronic oral studies comparing VO(ka)2 and VO(ma)2 over a six week period. In all studies, the most potent form of vanadium was the neutrally charged, water soluble, complex VO(ma)2.

  8. Studies on the distribution of platinum in tumour-bearing rats after the administration of platinum co-ordination complexes used in cancer chemotherapy

    International Nuclear Information System (INIS)

    Zeisler, R.; Lux, F.; Beck, W.

    1979-01-01

    Platinum co-ordination complexes like dichlorodiamineplatinum(II) (DDP) feature broad spectrum antitumour activity which, however, is marred by a certain toxicity related especially to renal tubular damage. The activity of such drugs depends on the chemical structure of the complexes, with changes in the ligands resulting in changes in their antitumour activity and toxicity. Assessments of the biological and toxicological effects of recently synthesized complexes must include distribution studies of platinum in the body. It is demonstrated that instrumental neutron activation analysis can be used for these studies because of its accuracy, precision and the low detection limit for platinum (approximately equal to 2 ng), when a standardized method is used. The time-dependent retention of platinum was determined in blood, liver, kidneys and cells of ascitic Walker 256 carcinosarcoma in tumour-bearing rats and controls after the administration of the cis-Pt(Gly-Gly-0Et) 2 Cl 2 complex. Two series of experiments, one with the therapeutic amount of the drug (80 mg/kg body weight) and one low-dose experiment with 1/100 of this amount, were carried out. The results of both experiments are discussed with regard to changes in the platinum concentration with time (0-48 h) in the different samples. From the data a selective uptake of the drug by the tumour cells, causing their destruction, is deduced. Because this drug has shown excellent antitumour activity, this observed selectivity suggests promise for its application in cancer chemotherapy, although platinum retention is still found in the kidneys, which might cause renal tubular damage. This latter aspect requires further clinical research to evaluate fully its effects. (author)

  9. Mechanochemical and thermal formation of 1H-benzotriazole coordination polymers and complexes of 3d-transition metals with intriguing dielectric properties.

    Science.gov (United States)

    Brede, Franziska A; Mühlbach, Friedrich; Sextl, Gerhard; Müller-Buschbaum, Klaus

    2016-07-14

    Liquid-assisted grinding (LAG) reactions have been successfully applied to achieve a series of complexes and coordination polymers based on divalent 3d-transition metal chlorides (TM chlorides) and the aromatic ligand 1H-benzotriazole (BtzH). The obtained substances were investigated via single crystal X-ray, powder X-ray determination and simultaneous DTA/TG analysis as model compounds for structural and chemical influences on their dielectric properties. Depending on the synthesis method, different constitutions and structures are observed. Two polymorphous forms of the 1D polymer [MnCl2(BtzH)2] (1 and 2) as well as the complexes [ZnCl2(BtzH)2]·BtzH (3) and [CoCl2(BtzH)2]·BtzH (4) have been obtained as phase-pure bulk substances via the mechanochemical LAG route, and even single crystals are available. For comparison, thermal reactions were also carried out and have led to the formation of the neutral complexes: [CoCl2(BtzH)2] (5) and [CoCl2(BtzH)4]·4BtzH (6), [ZnCl2(BtzH)2] (7) and the anionic complex BtzH2[CoCl3BtzH] (8). In addition, thermal treatment of 3 yields the benzotriazolium salt {(BtzH)2H}Cl (9). The transition metal compounds were additionally analysed regarding their dielectric properties by frequency-dependent as well as temperature-dependent permittivity investigations. It is intriguing that compounds 1 and 3 show remarkably low dielectric constants and loss factors up to 50 °C highlighting them as potential "low-k materials".

  10. Role of axial base coordination in isonitrile binding and chalcogen atom transfer to vanadium(III) complexes.

    Science.gov (United States)

    Majumdar, Subhojit; Stauber, Julia M; Palluccio, Taryn D; Cai, Xiaochen; Velian, Alexandra; Rybak-Akimova, Elena V; Temprado, Manuel; Captain, Burjor; Cummins, Christopher C; Hoff, Carl D

    2014-10-20

    The enthalpy of oxygen atom transfer (OAT) to V[(Me3SiNCH2CH2)3N], 1, forming OV[(Me3SiNCH2CH2)3N], 1-O, and the enthalpies of sulfur atom transfer (SAT) to 1 and V(N[t-Bu]Ar)3, 2 (Ar = 3,5-C6H3Me2), forming the corresponding sulfides SV[(Me3SiNCH2CH2)3N], 1-S, and SV(N[t-Bu]Ar)3, 2-S, have been measured by solution calorimetry in toluene solution using dbabhNO (dbabhNO = 7-nitroso-2,3:5,6-dibenzo-7-azabicyclo[2.2.1]hepta-2,5-diene) and Ph3SbS as chalcogen atom transfer reagents. The V-O BDE in 1-O is 6.3 ± 3.2 kcal·mol(-1) lower than the previously reported value for 2-O and the V-S BDE in 1-S is 3.3 ± 3.1 kcal·mol(-1) lower than that in 2-S. These differences are attributed primarily to a weakening of the V-Naxial bond present in complexes of 1 upon oxidation. The rate of reaction of 1 with dbabhNO has been studied by low temperature stopped-flow kinetics. Rate constants for OAT are over 20 times greater than those reported for 2. Adamantyl isonitrile (AdNC) binds rapidly and quantitatively to both 1 and 2 forming high spin adducts of V(III). The enthalpies of ligand addition to 1 and 2 in toluene solution are -19.9 ± 0.6 and -17.1 ± 0.7 kcal·mol(-1), respectively. The more exothermic ligand addition to 1 as compared to 2 is opposite to what was observed for OAT and SAT. This is attributed to less weakening of the V-Naxial bond in ligand binding as opposed to chalcogen atom transfer and is in keeping with structural data and computations. The structures of 1, 1-O, 1-S, 1-CNAd, and 2-CNAd have been determined by X-ray crystallography and are reported.

  11. Key role of higher order symmetry and electrostatic ligand field design in the magnetic relaxation of low-coordinate Er(iii) complexes.

    Science.gov (United States)

    Singh, Saurabh Kumar; Pandey, Bhawana; Velmurugan, Gunasekaran; Rajaraman, Gopalan

    2017-09-12

    The conceptual framework of electrostatic ligand field modulation based on oblate/prolate type electron density of lanthanide ions is one of the most successful approaches to enhance barrier height in lanthanide-based single-ion magnets. Recently, a tetra coordinated [Er{N(SiMe 3 ) 2 }s 3 Cl]·2THF (1) complex with an unfavourable ligand field showed slow relaxation of magnetization in zero field and challenges the concept of electrostatic ligand field modulation. To unravel the magnetic relaxation in this complex, we carried out a detailed theoretical investigation on three Er(iii) complexes belonging to the same family of single-ion magnets. The CASSCF/PT2 + RASSI-SO approach highlights that the concept of electrostatic ligand field modulation based on oblate/prolate type is still valid in these complexes, and the relaxation dynamics observed can be rationalized by accounting for both the symmetry and geometrical distortions around the Er(iii) ion. Using ab initio computed blockade barriers and crystal field analysis, we analysed the key components of the magnetic relaxation. Our study suggests that in these structures, the Er(iii) ion shifted out of the triangular plane formed by the three nitrogen donor atoms and this out-of-plane shift (τ) significantly influences the slow-relaxation of magnetization. In order to gain deeper insights into the nature of metal-ligand bonding, and to predict quantitatively the strength of the axial and equatorial ligand field, ELF, QTAIM, and EDA analysis were carried out in these complexes. Our findings highlight that the molecules possessing large barrier height for magnetic relaxation are due to the combined effect of a favourable ligand field and the symmetry around the Er(iii) ion. To understand the intricate role of both effects, several robust magneto-structural correlations were developed. Besides, the lanthanide-halogen covalency was also found to play a vital role in controlling the magnetic anisotropy and thus the

  12. Complex chemistry

    International Nuclear Information System (INIS)

    Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

    2006-06-01

    This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

  13. DDX3 directly regulates TRAF3 ubiquitination and acts as a scaffold to co-ordinate assembly of signalling complexes downstream from MAVS.

    Science.gov (United States)

    Gu, Lili; Fullam, Anthony; McCormack, Niamh; Höhn, Yvette; Schröder, Martina

    2017-02-15

    The human DEAD-box helicase 3 (DDX3) has been shown to contribute to type I interferon (IFN) induction downstream from antiviral pattern recognition receptors. It binds to TANK-binding kinase 1 and IκB-kinase-ε (IKKε), the two key kinases mediating activation of IFN regulatory factor (IRF) 3 and IRF7. We previously demonstrated that DDX3 facilitates IKKε activation downstream from RIG-I and then links the activated kinase to IRF3. In the present study, we probed the interactions between DDX3 and other key signalling molecules in the RIG-I pathway and identified a novel direct interaction between DDX3 and TNF receptor-associated factor 3 (TRAF3) mediated by a TRAF-interaction motif in the N-terminus of DDX3, which was required for TRAF3 ubiquitination. Interestingly, we observed two waves of K63-linked TRAF3 ubiquitination following RIG-I activation by Sendai virus (SeV) infection, both of which were suppressed by DDX3 knockdown. We also investigated the spatiotemporal formation of endogenous downstream signalling complexes containing the mitochondrial antiviral signalling (MAVS) adaptor, DDX3, IκB-kinase-ε (IKKε), TRAF3 and IRF3. DDX3 was recruited to MAVS early after SeV infection, suggesting that it might mediate subsequent recruitment of other molecules. Indeed, knockdown of DDX3 prevented the formation of TRAF3-MAVS and TRAF3-IKKε complexes. Based on our data, we propose that early TRAF3 ubiquitination is required for the formation of a stable MAVS-TRAF3 complex, while the second wave of TRAF3 ubiquitination mediates IRF3 recruitment and activation. Our study characterises DDX3 as a multifunctional adaptor molecule that co-ordinates assembly of different TRAF3, IKKε and IRF3-containing signalling complexes downstream from MAVS. Additionally, it provides novel insights into the role of TRAF3 in RIG-I signalling. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  14. Co-ordinate expression of the pre-T-cell receptor complex and a novel immature thymocyte-specific antigen, IMT-1, during thymocyte development.

    Science.gov (United States)

    Tong, J J; Kishi, H; Nagata, T; Muraguchi, A

    1999-01-01

    Previously we described a monoclonal antibody (mAb) that reacted with a cell-surface antigen, immature thymocyte antigen-1 (IMT-1), which is expressed on thymocytes of late CD4- CD8- (double negative) to early CD4+ CD8+ (double positive) differentiation stages. In this study, we investigated the expression of IMT-1 on various cell lineages in thymus as well as in peripheral lymphoid organs. We found that IMT-1 is expressed on T-cell receptor (TCR)-betalo and TCR-deltalo thymocytes, but not on TCR-betahi, TCR-deltahi or natural killer (NK)1.1+ thymocytes, or on peripheral alpha beta or gamma delta T cells. We also investigated the kinetics of expression of IMT-1 during fetal thymocyte development and compared it with the expression of the pre-TCR complex, comprising CD3, pre-TCR-alpha (pTalpha) and TCR-beta. We found that expression of both was similar, starting at day 14.5 of gestation, peaking on day 16.5 and gradually decreasing thereafter. Furthermore, the expression of both IMT-1 and pTalpha was drastically reduced when DN thymocytes in recombination activating gene (RAG)-2-/- mice were challenged in vivo with anti-CD3 mAb. These results indicate that IMT-1 is expressed on not only immature thymocytes of alpha beta T-cell lineage but also on those of gamma delta T-cell lineage, and that the expression of IMT-1 and the pre-TCR complex is co-ordinately regulated during the alpha beta lineage thymocyte development.

  15. Coordination chemistry of technetium

    International Nuclear Information System (INIS)

    Together with development of chemistry of radiopharmaceuticals, coordination chemistry of technetium has recently progressed. The synthetic procedures of technetium complexes have also been established in a various oxidation states. Especially, technetium(V) complexes which possess a Tc=0 or 0=Tc = 0 core are interested from a view point kinetic stability. In the present paper, substitution reaction mechanisms of Tc(V), Tc(IV) and Tc(III) complexes coordinated with a β-diketone as ligand are discussed in connection with the structural chemistry of technetium complexes. The base hydrolysis of halobis(β-diketonato)oxotechnetium(V) and dihalobis (β-diketonato)technetium(IV) complexes liberate halide ion by the attack of hydroxide ion, followed by the liberation of β-diketones. Technetium is found to be pertechnetate as a final product

  16. Introduction to Coordination Chemistry

    CERN Document Server

    Lawrance, Geoffrey Alan

    2010-01-01

    Introduction to Coordination Chemistry examines and explains how metals and molecules that bind as ligands interact, and the consequences of this assembly process. This book describes the chemical and physical properties and behavior of the complex assemblies that form, and applications that may arise as a result of these properties. Coordination complexes are an important but often hidden part of our world?even part of us?and what they do is probed in this book. This book distills the essence of this topic for undergraduate students and for research scientists.

  17. Evans-Showell-Type Polyoxometalates Constructing High-Dimensional Inorganic-Organic Hybrid Compounds with Copper-Organic Coordination Complexes: Synthesis and Oxidation Catalysis.

    Science.gov (United States)

    An, Haiyan; Hou, Yujiao; Wang, Lin; Zhang, Yumeng; Yang, Wei; Chang, ShenZhen

    2017-10-02

    Four new hybrid architectures containing a [Co 2 Mo 10 H 4 O 38 ] 6- polyoxoanion, (en)[Cu 3 (ptz) 4 (H 2 O) 4 ][Co 2 Mo 10 H 4 O 38 ]·24H 2 O (1), (Hbim) 2 [{Cu(bim) 2 (H 2 O) 2 } 2 {Co 2 Mo 10 H 4 O 38 }]·5H 2 O (2), H 2 [Cu(dpdo) 3 (H 2 O) 4 ][{Cu 2 (dpdo) 3 (H 2 O) 4 (CH 3 CN)} 2 {Co 2 Mo 10 H 4 O 38 } 2 ]·9H 2 O (3), and (H 2 bpp) 4 [{Cu(H 2 O) 2 }{NaCo 2 Mo 10 H 4 O 38 } 2 ]·10H 2 O (4), where ptz = 5-(4-pyridyl)-1H-tetrazole, en = ethylenediamine, bim = benzimidazole, dpdo = 4,4'-bipyridine-N,N'-dioxide, and bpp = 1,3-bis(4-pyridyl)propane, have been prepared and characterized through elemental analysis, thermogravimetric analysis, IR spectroscopy, and powder and single-crystal X-ray diffraction. Compound 1 shows a 3D host-guest framework composed of 3D Cu-ptz as the host and Evans-Showell-type polyoxoanion [Co 2 Mo 10 H 4 O 38 ] 6- as the guest. Compound 2 is constructed from [Co 2 Mo 10 H 4 O 38 ] 6- polyoxoanions and Cu-bim coordination complexes to form a 2D covalent layer. Compound 3 also exhibits a 2D hybrid network based on [Co 2 Mo 10 H 4 O 38 ] 6- polyoxoanions linked by Cu-dpdo coordination groups. Compound 4 is a 1D double-chain structure composed of [Co 2 Mo 10 H 4 O 38 ] 6- polyoxoanions joined together by Na + and Cu 2+ cations. As far as we know, compound 1 is the first host-guest compound with an Evans-Showell-type polyoxometalate as the guest, and compounds 2 and 3 are the first 2D inorganic-organic hybrid architectures constructed from Evans-Showell-type polyoxometalates. Compounds 1-4 are redox catalysts that heterogeneously prompt sulfide and alcohol oxidation with excellent efficiency.

  18. Binuclear complexes of technetium. Evidence for bis(terdentate)bidentate coordination by the bridging ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine to technetium(V)

    International Nuclear Information System (INIS)

    Du Preez, J.G.H.; Gerber, T.I.A.; Gibson, M.L.; Geyser, R.

    1990-01-01

    The authors have used the potentially bis(terdentate) nitrogen aromatic heterocyclic ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz) to prepare mono- and bimetallic technetium(V) complexes bound to tppz. The stimulus for the development of the coordination chemistry of the man-made element technetium is provided by the use of complexes of this element as anatomical imaging agents in nuclear medicine. Although the chemistry of technetium(V) with nitrogen donor ligands is well understood, no complexes have been prepared using potentially terdentate neutral nitrogen donor ligands of this metal in the +5 oxidation state

  19. Synthesis of differently substituted tacn-based ligands. Towards the control of solubility and electronic and steric properties of uranium coordination complexes

    Energy Technology Data Exchange (ETDEWEB)

    Nizovtsev, Alexey V.; Scheurer, Andreas; Kosog, Boris; Heinemann, Frank W.; Meyer, Karsten [Department Chemie und Pharmazie, Lehrstuhl fuer Anorganische und Allgemeine Chemie, Universitaet Erlangen-Nuernberg, Erlangen (Germany)

    2013-05-15

    Starting from phenols {sup R1,R2}ArOH (5) and the anisole derivative 3,5-di-tert-butyl-2-methoxybenzyl bromide (13), a series of new tacn-based ligands ({sup R1,R2}ArOR{sup 3}){sub 3}tacn (2) have been synthesized with substituents of varying bulkiness and electronic nature at the ortho and para positions with respect to the oxygen coordination site. It was observed that these groups not only determine the steric shielding and solubility properties of 2, but also deactivate the reactivity of the phenols in the modified Mannich reaction when electron-withdrawing groups are introduced at the para position in 5. Treatment of the ligands with UCl{sub 4} in thf led to the isolation of four uranium(IV) chloro complexes [{("R"1","R"2ArO)_3tacn}U{sup IV}Cl] (14), which were characterized by different spectroscopic and physical methods (e.g., {sup 1}H NMR, UV/Vis, SQUID), corroborating the +4 oxidation state in 14. Single-crystal X-ray structure analyses revealed that 14a.CH{sub 2}Cl{sub 2}.CH{sub 3}CN and 14b.1.25CH{sub 2}Cl{sub 2} crystallize in the chiral, orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} [a = 24.934(3), b = 27.941(3), c = 9.045(1) Aa, V = 6302(2) Aa{sup 3}, Z = 4] and the chiral, hexagonal space group P6{sub 3} [a = 22.097(3), c = 17.941(2) Aa, V = 7587(2) Aa{sup 3}, Z = 4], respectively. Interestingly, complexes 14a,b self-organize in the solid state into homochiral 1D polymeric superstructures as a result of weak intermolecular C-H..Cl contacts. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Polymeric coordination compounds

    Indian Academy of Sciences (India)

    Administrator

    Metal coordination polymers with one- and two-dimensional structures are of current interest due to their possible relevance to material science 1. In continuation of our previous studies 2,3, several new polymeric compounds are reported here. Among the complexes of silver with aminomethyl pyridine (amp) ...

  1. Mechanochemical Synthesis of 3d Transition-Metal-1,2,4-Triazole Complexes as Precursors for Microwave-Assisted and Thermal Conversion to Coordination Polymers with a High Influence on the Dielectric Properties.

    Science.gov (United States)

    Brede, Franziska A; Heine, Johanna; Sextl, Gerhard; Müller-Buschbaum, Klaus

    2016-02-18

    The complexes [MCl2 (TzH)4] (M=Mn (1), Fe (2); TzH=1,2,4-1H-triazole) and [ZnCl2 (TzH)2] (3) have been obtained by mechanochemical reactions of the corresponding divalent metal chloride and 1,2,4-1H-triazole. They were successfully used as precursors for the formation of coordination polymers either by a microwave-assisted reaction or by thermal conversion. For manganese, the conversion directly yielded 1∞ [MnCl2 TzH] (4), whereas for the iron-containing precursor, 1∞ [FeCl2 TzH] (6), was formed via the intermediate coordination polymer 1∞ [FeCl(TzH)2]Cl (5). For cobalt, the isotypic polymer 1∞ [CoCl(TzH)2]Cl (7) was obtained, but exclusively by a microwave-induced reaction directly from CoCl2 . The crystal structures were resolved from single crystals and powders. The dielectric properties were determined and revealed large differences in permittivity between the precursor complexes and the rigid chain-like coordination polymers. Whereas the monomeric complexes exhibit very different dielectric behaviour, depending on the transition metal, from "low-k" to "high-k" with the permittivity ranging from 4.3 to >100 for frequencies of up to 1000 Hz, the coordination polymers and complexes with strong intermolecular interactions are all close to "low-k" materials with very low dielectric constants up to 50 °C. Therefore, the conversion procedures can be used to deliberately influence the dielectric properties from complex to polymer and for different 3d transition-metal ions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Sonochemical synthesis of two novel Pb(II) 2D metal coordination polymer complexes: New precursor for facile fabrication of lead(II) oxide/bromide micro-nanostructures.

    Science.gov (United States)

    Hayati, Payam; Suárez-García, Salvio; Gutierrez, Angel; Şahin, Ertan; Molina, Daniel Ruiz; Morsali, Ali; Rezvani, Ali Reza

    2018-04-01

    Two new lead(II) coordination polymer complexes (CSCs) (2D), [Pb 2 (L) 2 (Br) 2 ] n ·H 2 O (1), [Pb 2 (HL / )(L / )(H 2 O) 2 ] n ·H 2 O (2), where L = C 6 H 5 NO 2 (2-pyridinecarboxylic acid) and L /  = C 9 H 6 O 6 (1,3,5-tricarboxylic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or microsized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. Single crystal X-ray analyses on complexes 1 and 2 shows that Pb 2+ ions are 8-coordinated, 7 and 9-coordinated, respectively. Topological analysis shows that the compound 1 and 2 are 4,6L26 and bnn net, respectively. However, neither the shape nor the morphology is maintained, showing the role of sonochemistry to modulate both morphology and dimensions of the resulting crystalline material, independently of whether we have a 2D coordination polymer (CP). Finally, micro structuration of lead(II) bromide oxide and lead(II) oxide have been prepared by calcination of two different lead (II) CPs at 700 °C that were characterized by SEM and XRD. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Síntese e atividade citotóxica de alguns azido-ciclopaladados estabilizados com ligantes bifosfínicos Synthesis and cytotoxicity of some cyclometallated palladium (II complexes containing coordinated azide and diphosphines

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Fávero Caires

    1999-06-01

    Full Text Available Some cyclopalladated compounds containing the azido group ligand and the (C-N ring of N,N-dimethylbenzylamine have been prepared by bridge opening reactions of dimmer azide complex precursor with some diphosphines in different stoichiometric quantities. The neutral or ionic, mono or binuclear complexes synthesized were characterized by elemental analyses, I. R. spectroscopy and NMR techniques. The series of complexes was screened for cytotoxicity against a panel three human tumour cells lines(C6,Hep-2,HeLa. All complexes were found to be cytotoxic (IC50 at µM concentrations while one complex having the coordination bond N-Pd ruptured also displayed some differential cytotoxicity.

  4. Possibility of extending space-time coordinates

    International Nuclear Information System (INIS)

    Wang Yongcheng.

    1993-11-01

    It has been shown that one coordinate system can describe a whole space-time region except some supersurfaces on which there are coordinate singularities. The conditions of extending a coordinate from real field to complex field are studied. It has been shown that many-valued coordinate transformations may help us to extend space-time regions and many-valued metric functions may make one coordinate region to describe more than one space-time regions. (author). 11 refs

  5. Coordination cycles

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    2008-01-01

    Roč. 63, č. 1 (2008), s. 308-327 ISSN 0899-8256 Institutional research plan: CEZ:AV0Z70850503 Keywords : global games * coordination * crises * cycles and fluctuations Subject RIV: AH - Economics Impact factor: 1.333, year: 2008

  6. Coordination cycles

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    -, č. 274 (2005), s. 1-26 ISSN 1211-3298 Institutional research plan: CEZ:AV0Z70850503 Keywords : coordination * crises * cycles and fluctuations Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp274.pdf

  7. Electronic transitions and bonding properties in a series of five-coordinate "16-electron" complexes [Mn(CO)3(L2)]- (L2 = chelating redox-active .pi.-donor ligand)

    Czech Academy of Sciences Publication Activity Database

    Hartl, F.; Rosa, P.; Ricard, L.; Le Floch, P.; Záliš, Stanislav

    2007-01-01

    Roč. 251, 3-4 (2007), s. 557-576 ISSN 0010-8545 R&D Projects: GA MŠk 1P05OC068; GA AV ČR 1ET400400413 Institutional research plan: CEZ:AV0Z40400503 Keywords : manganese carbonyl * .pi.-donor ligand * electronic delocalization * Five-coordinate complex Subject RIV: CG - Electrochemistry Impact factor: 8.568, year: 2007

  8. Nitrate-Bridged One-Dimension Coordination Polymer Self-Assembled from a N4O2-Tetraiminodiphenolate Dicopper(II Macrocyclic Complex

    Directory of Open Access Journals (Sweden)

    Julio Cesar da Rocha

    2015-01-01

    Full Text Available Herein we report on the synthesis and single crystal X-ray structure characterization of [{Cu2(tidf(μ-NO3}∞]ClO4 (tidf = a Robson type macrocyclic ligand obtained upon condensation of 2,6-diformyl-4-methylphenol and 1,3-diaminopropane. The coordination geometry around the copper(II is square-pyramidal and has [Cu2(tidf]2+ units connected to each other through nitrate bridges extending as a one-dimension coordination polymer. The compound exhibits an extensive supramolecular structure supported by nonclassic hydrogen bonding between C-H⋯Operchlorate and C-H⋯Onitrate.

  9. Studies on coordination chemistry and bioactivity of metal complexes of a bidentate NN schiff base, (2-pyridyl-methylene)(phenyl) hydrazine, produced from the condensation of pyridine-2-carboxaldehyde with phenylhydrazine

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Zakaria, C.M.; Idrus, Razmi Mohd; Crouse, Karen A.; Ali, A.M.; Yamin, B.M.; Fun, H.-K.

    2003-07-01

    A bidentate Schiff base, (2-pyridyl-methylene)(phenyl) hydrazine, with NN donor sequence, was isolated from the condensation of pyridine-2-carboxaldehyde with phenylhydrazine in ethanol. Metal complexes of this ligand with Ni(II), Zn(It), and Cu(n) ions were synthesized and characterized by a variety of physico-chemical techniques. The structure of the Schiff base was solved by X-ray diffraction studies, which indicated that it was monoclinic with a space group of C2/c. The complexes were all four coordinated. The compounds were tested against four pathogenic bacteria and fungi. The nickel complex, [Ni(NN) 2 Cl 2 ], in particular, was found to be active against all the fungi tested. The complexes were however inactive against leukemic cell lines (CEM-SS). (author)

  10. TECHNICAL COORDINATION

    CERN Multimedia

    A. Ball

    Overview From a technical perspective, CMS has been in “beam operation” state since 6th November. The detector is fully closed with all components operational and the magnetic field is normally at the nominal 3.8T. The UXC cavern is normally closed with the radiation veto set. Access to UXC is now only possible during downtimes of LHC. Such accesses must be carefully planned, documented and carried out in agreement with CMS Technical Coordination, Experimental Area Management, LHC programme coordination and the CCC. Material flow in and out of UXC is now strictly controlled. Access to USC remains possible at any time, although, for safety reasons, it is necessary to register with the shift crew in the control room before going down.It is obligatory for all material leaving UXC to pass through the underground buffer zone for RP scanning, database entry and appropriate labeling for traceability. Technical coordination (notably Stephane Bally and Christoph Schaefer), the shift crew and run ...

  11. Synthesis, chemistry and catalytic activity of complexes of lanthanide and actinide metals in unusual oxidation states and coordination environments. Progress report, February 1, 1978--January 31, 1979

    International Nuclear Information System (INIS)

    Evans, W.J.

    1978-11-01

    Previous syntheses of Ln(olefin) complexes and their catalytic effect on the hydrogenation of the olefin are discussed. The tert-butyl complexes of Sn, Er, and Yb were synthesized and their decomposition studied

  12. Coordinating Work with Groupware

    DEFF Research Database (Denmark)

    Pors, Jens Kaaber; Simonsen, Jesper

    2003-01-01

    One important goal of employing groupware is to make possible complex collaboration between geographically distributed groups. This requires a dual transformation of both technology and work practice. The challenge is to re­duce the complexity of the coordination work by successfully inte......­grating the protocol stipulating the collaboration and the ar­te­fact, in form of the groupware application, mediating the col­laboration. This paper analyses a generic groupware application that was deployed in a large financial organisation in order to support working groups distributed throughout four countries....... Using the CSCW frame­work of coordination mechanisms, we have elicited six general factors influencing the integration of the groupware application in two situations....

  13. Coordinated unbundling

    DEFF Research Database (Denmark)

    Timmermans, Bram; Zabala-Iturriagagoitia, Jon Mikel

    2013-01-01

    Public procurement for innovation is a matter of using public demand to trigger innovation. Empirical studies have demonstrated that demand-based policy instruments can be considered to be a powerful tool in stimulating innovative processes among existing firms; however, the existing literature has...... not focused on the role this policy instrument can play in the promotion of (knowledge-intensive) entrepreneurship. This paper investigates this link in more detail and introduces the concept of coordinated unbundling as a strategy that can facilitate this purpose. We also present a framework on how...... to organise public procurement for innovation around this unbundling strategy and provide a set of challenges that need to be addressed....

  14. TECHNICAL COORDINATION

    CERN Multimedia

    A. Ball

    2010-01-01

    Operational Experience At the end of the first full-year running period of LHC, CMS is established as a reliable, robust and mature experiment. In particular common systems and infrastructure faults accounted for <0.6 % CMS downtime during LHC pp physics. Technical operation throughout the entire year was rather smooth, the main faults requiring UXC access being sub-detector power systems and rack-cooling turbines. All such problems were corrected during scheduled technical stops, in the shadow of tunnel access needed by the LHC, or in negotiated accesses or access extensions. Nevertheless, the number of necessary accesses to the UXC averaged more than one per week and the technical stops were inevitably packed with work packages, typically 30 being executed within a few days, placing a high load on the coordination and area management teams. It is an appropriate moment for CMS Technical Coordination to thank all those in many CERN departments and in the Collaboration, who were involved in CMS techni...

  15. Preparation, Spectrochemical, and Computational Analysis of L-Carnosine (2-[(3-Aminopropanoylamino]-3-(1H-imidazol-5-ylpropanoic Acid and Its Ruthenium (II Coordination Complexes in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Myalo Sabela

    2011-12-01

    Full Text Available This study reports the synthesis and characterization of novel ruthenium (II complexes with the polydentate dipeptide, L-carnosine (2-[(3-aminopropanoylamino]-3-(1H-imidazol-5-ylpropanoic acid. Mixed-ligand complexes with the general composition [MLp(Clq(H2Or]·xH2O (M = Ru(II; L = L-carnosine; p = 3 − q; r = 0–1; and x = 1–3 were prepared by refluxing aqueous solutions of the ligand with equimolar amounts of ruthenium chloride (black-alpha form at 60 °C for 36 h. Physical properties of the complexes were characterized by elemental analysis, DSC/TGA, and cyclic voltammetry. The molecular structures of the complexes were elucidated using UV-Vis, ATR-IR, and heteronuclear NMR spectroscopy, then confirmed by density function theory (DFT calculations at the B3LYP/LANL2DZ level. Two-dimensional NMR experiments (1H COSY, 13C gHMBC, and 15N gHMBC were also conducted for the assignment of chemical shifts and calculation of relative coordination-induced shifts (RCIS by the complex formed. According to our results, the most probable coordination geometries of ruthenium in these compounds involve nitrogen (N1 from the imidazole ring and an oxygen atom from the carboxylic acid group of the ligand as donor atoms. Additional thermogravimetric and electrochemical data suggest that while the tetrahedral-monomer or octahedral-dimer are both possible structures of the formed complexes, the metal in either structure occurs in the (2+ oxidation state. Resulting RCIS values indicate that the amide-carbonyl, and the amino-terminus of the dipeptide are not involved in chelation and these observations correlate well with theoretical shift predictions by DFT.

  16. [Civilian-military coordination].

    Science.gov (United States)

    de Montravel, G

    2002-01-01

    Current humanitarian emergencies create complex, mutidimensional situations that stimulate simultaneous responses from a wide variety of sources including governments, non-governmental organizations (NGO), United Nations agencies, and private individuals. As a result, it has become essential to establish a coherent framework in which each actor can contribute promptly and effectively to the overall effort. This is the role of the United Nations Office for the Coordination of Humanitarian Affairs. Regardless of the circumstances and level of coordination, cooperation and collaboration between humanitarian and military personnel, it is necessary to bear in mind their objectives. The purpose of humanitarian action is to reduce human suffering. The purpose of military intervention is to stop warfare. The author of this article will discuss the three major obstacles to civilian-military coordination (strategic, tactical, and operational). Operations cannot be conducted smoothly and differences cannot be ironed out without mutual respect between the two parties, an explicit definition of their respective duties and responsibilities, a clear understanding of their cultural differences, and the presence of an organization and facilities for coordination and arbitrage by a neutral referee.

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

    DEFF Research Database (Denmark)

    Broge, Louise; Søtofte, Inger; Jensen, Kristian

    2007-01-01

    Seven cobalt(III) complexes of the macrobicyclic tetraamine ligand [2(4).3(1)]adamanzane ([2(4).3(1)]adz) are reported along with the crystal structure of six of these complexes. The solid state and solution structures are discussed, and a detailed assignment of the NMR spectra of the sulfato com...

  18. A Six-Coordinate Peroxynitrite Low-Spin Iron(III) Porphyrinate Complex-The Product of the Reaction of Nitrogen Monoxide (·NO(g)) with a Ferric-Superoxide Species.

    Science.gov (United States)

    Sharma, Savita K; Schaefer, Andrew W; Lim, Hyeongtaek; Matsumura, Hirotoshi; Moënne-Loccoz, Pierre; Hedman, Britt; Hodgson, Keith O; Solomon, Edward I; Karlin, Kenneth D

    2017-12-06

    Peroxynitrite ( - OON═O, PN) is a reactive nitrogen species (RNS) which can effect deleterious nitrative or oxidative (bio)chemistry. It may derive from reaction of superoxide anion (O 2 •- ) with nitric oxide (·NO) and has been suggested to form an as-yet unobserved bound heme-iron-PN intermediate in the catalytic cycle of nitric oxide dioxygenase (NOD) enzymes, which facilitate a ·NO homeostatic process, i.e., its oxidation to the nitrate anion. Here, a discrete six-coordinate low-spin porphyrinate-Fe III complex [(P Im )Fe III ( - OON═O)] (3) (P Im ; a porphyrin moiety with a covalently tethered imidazole axial "base" donor ligand) has been identified and characterized by various spectroscopies (UV-vis, NMR, EPR, XAS, resonance Raman) and DFT calculations, following its formation at -80 °C by addition of ·NO (g) to the heme-superoxo species, [(P Im )Fe III (O 2 •- )] (2). DFT calculations confirm that 3 is a six-coordinate low-spin species with the PN ligand coordinated to iron via its terminal peroxidic anionic O atom with the overall geometry being in a cis-configuration. Complex 3 thermally transforms to its isomeric low-spin nitrato form [(P Im )Fe III (NO 3 - )] (4a). While previous (bio)chemical studies show that phenolic substrates undergo nitration in the presence of PN or PN-metal complexes, in the present system, addition of 2,4-di-tert-butylphenol ( 2,4 DTBP) to complex 3 does not lead to nitrated phenol; the nitrate complex 4a still forms. DFT calculations reveal that the phenolic H atom approaches the terminal PN O atom (farthest from the metal center and ring core), effecting O-O cleavage, giving nitrogen dioxide (·NO 2 ) plus a ferryl compound [(P Im )Fe IV ═O] (7); this rebounds to give [(P Im )Fe III (NO 3 - )] (4a).The generation and characterization of the long sought after ferriheme peroxynitrite complex has been accomplished.

  19. New insights into the coordination chemistry of Schiff bases derived from amino acids: Planar [Ni4] complexes with tyrosine side-chains

    Science.gov (United States)

    Muche, Simon; Hołyńska, Małgorzata

    2017-08-01

    Structure and properties of a rare metal complex of the chiral Schiff base ligand derived from ortho-vanillin and L-tyrosine are presented. This study is a continuation of research on ligands containing biologically compatible moieties. The ligand is also fully characterized in form of a sodium salt, in particular in solution, for the first time. The metal complex contains a unique bowl-shaped [Ni4] core. Its structure is investigated both in solution (ESI-MS, NMR) and in solid state (X-ray diffraction studies). Under certain conditions the complex can be isolated as crystalline DMF solvate which is studied in solid state.

  20. Coordination chemistry of bis(delta-camphorquinone dioximato)nickel(II) and -palladium(II). Reactions and structural studies of some M/sub 3/Ag/sub 3/ cluster complexes of camphorquinone dioxime

    Energy Technology Data Exchange (ETDEWEB)

    Ma, M.S.; Angelici, R.J.; Powell, D.; Jacobson, R.A.

    1980-10-01

    Reactions of AgNO/sub 3/ with Ni(delta-HCQD)/sub 2/ or Pd(delta-HCQD)/sub 2/, where delta-HCQD/sup -/ is delta-camphorquinone dioximato, yielded the hexanuclear metal cluster complexes (Ni(delta-HCQD)/sub 2/Ag)/sub 3/.2.5CHCl/sub 3/, Ni-Ag, and (Pd(delta-HCQD)/sub 2/Ag)/sub 3/.2CHCl/sub 3/, Pd-Ag, respectively. X-ray crystallographic studies performed on both complexes showed them to belong to space group P2/sub 1/2/sub 1/2/sub 1/. The unit cell dimensions of Ni-Ag are a = 15.990 (5) A, B = 38.44 (1) A, c = 13.437 (5) A, V = 8260.97 A/sup 3/, and Z = 4 while those of Pd-Ag are a = 16.110 (6), b = 38.92 (1), c = 13.393 (3) A, V = 8395.55 A/sup 3/, and Z = 4. Block-diagonal least-squares refinement of 3021 observed reflections for Ni-Ag and 6112 for Pd-Ag converged to R/sub F/ = 10.7 and 11.4 (R/sub w/ = 12.7 and 15.0) for the Ni-Ag and Pd-Ag structures, respectively. Their structures indicate that each hexanuclear molecule consists of three individual M(delta-HCQD)/sub 2//sup -/units which act as multidentate ligands coordinating to a linear chain of three silver atoms. The coordination geometry around each M ion in the M(delta-HCQD)/sub 2//sup -/units is square planar, and the delta-HCQD/sup -/ligands are coordinated to M via N and O atoms. The Ag in the center of the molecule is coordinated to six O atoms with average Ag-O distances of 2.49 (3) and 2.45 (2) A for Ni-Ag and Pd-Ag, respectively. The two silver atoms at the ends of the chain are each coordinated to three nitrogen atoms from the M(delta-HCQD)/sub 2//sup -/ units with average Ag-N distances of 2.20 (4) and 2.27 (3) A, respectively. The Ag-Ag distances, 3.059 (5) and 3.052 (5) A in Ni-Ag and 3.173 (3) and 3.179 (3) A in Pd-Ag, are somewhat longer than those (2.89 A) in Ag metal and indicate that there are Ag-Ag interactions along the linear chains.

  1. Effect of applied hydrostatic pressure on the quenching kinetics, and electronic and molecular structure of eight and nine-coordinate lanthanide complexes in solution

    International Nuclear Information System (INIS)

    Maupin, C.L.; Riehl, J.P.

    1998-01-01

    Full text: Applied hydrostatic pressure may be used as a probe of the reaction mechanism for various solution reactions involving lanthanide ions. In this work we report on the use of high pressure to probe the mechanism of enantioselective quenching between racemic luminescent lanthanide complexes containing Dy(III) Tb(III) and Eu(III), and optically active transition metal complexes as quenchers. Diastereomeric rate constants are obtained from a biexponential fit of the luminescence decay. Particular attention will be given to solvation effects on the measured diastereomeric rate constants. The source of chirality is ascribed to a enantioselective rearrangement step within a bimolecular 'encounter' complex yielding a intermolecular geometry in which the energy transfer is efficient. The effect of high pressure on the molecular and electronic structure of these complexes will also be discussed

  2. Nonlinear optical and G-Quadruplex DNA stabilization properties of novel mixed ligand copper(II) complexes and coordination polymers: Synthesis, structural characterization and computational studies

    Science.gov (United States)

    Rajasekhar, Bathula; Bodavarapu, Navya; Sridevi, M.; Thamizhselvi, G.; RizhaNazar, K.; Padmanaban, R.; Swu, Toka

    2018-03-01

    The present study reports the synthesis and evaluation of nonlinear optical property and G-Quadruplex DNA Stabilization of five novel copper(II) mixed ligand complexes. They were synthesized from copper(II) salt, 2,5- and 2,3- pyridinedicarboxylic acid, diethylenetriamine and amide based ligand (AL). The crystal structure of these complexes were determined through X-ray diffraction and supported by ESI-MAS, NMR, UV-Vis and FT-IR spectroscopic methods. Their nonlinear optical property was studied using Gaussian09 computer program. For structural optimization and nonlinear optical property, density functional theory (DFT) based B3LYP method was used with LANL2DZ basis set for metal ion and 6-31G∗ for C,H,N,O and Cl atoms. The present work reveals that pre-polarized Complex-2 showed higher β value (29.59 × 10-30e.s.u) as compared to that of neutral complex-1 (β = 0.276 × 10-30e.s.u.) which may be due to greater advantage of polarizability. Complex-2 is expected to be a potential material for optoelectronic and photonic technologies. Docking studies using AutodockVina revealed that complex-2 has higher binding energy for both G-Quadruplex DNA (-8.7 kcal/mol) and duplex DNA (-10.1 kcal/mol). It was also observed that structure plays an important role in binding efficiency.

  3. Temporal coordination between performing musicians.

    Science.gov (United States)

    Loehr, Janeen D; Palmer, Caroline

    2011-11-01

    Many common behaviours require people to coordinate the timing of their actions with the timing of others' actions. We examined whether representations of musicians' actions are activated in coperformers with whom they must coordinate their actions in time and whether coperformers simulate each other's actions using their own motor systems during temporal coordination. Pianists performed right-hand melodies along with simple or complex left-hand accompaniments produced by themselves or by another pianist. Individual performers' preferred performance rates were measured in solo performance of the right-hand melody. The complexity of the left-hand accompaniment influenced the temporal grouping structure of the right-hand melody in the same way when it was performed by the self or by the duet partner, providing some support for the action corepresentation hypothesis. In contrast, accompaniment complexity had little influence on temporal coordination measures (asynchronies and cross-correlations between parts). Temporal coordination measures were influenced by a priori similarities between partners' preferred rates; partners who had similar preferred rates in solo performance were better synchronized and showed mutual adaptation to each other's timing during duet performances. These findings extend previous findings of action corepresentation and action simulation to a task that requires precise temporal coordination of independent yet simultaneous actions.

  4. RUN COORDINATION

    CERN Multimedia

    C. Delaere

    2013-01-01

    Since the LHC ceased operations in February, a lot has been going on at Point 5, and Run Coordination continues to monitor closely the advance of maintenance and upgrade activities. In the last months, the Pixel detector was extracted and is now stored in the pixel lab in SX5; the beam pipe has been removed and ME1/1 removal has started. We regained access to the vactank and some work on the RBX of HB has started. Since mid-June, electricity and cooling are back in S1 and S2, allowing us to turn equipment back on, at least during the day. 24/7 shifts are not foreseen in the next weeks, and safety tours are mandatory to keep equipment on overnight, but re-commissioning activities are slowly being resumed. Given the (slight) delays accumulated in LS1, it was decided to merge the two global runs initially foreseen into a single exercise during the week of 4 November 2013. The aim of the global run is to check that we can run (parts of) CMS after several months switched off, with the new VME PCs installed, th...

  5. RUN COORDINATION

    CERN Multimedia

    Christophe Delaere

    2013-01-01

    The focus of Run Coordination during LS1 is to monitor closely the advance of maintenance and upgrade activities, to smooth interactions between subsystems and to ensure that all are ready in time to resume operations in 2015 with a fully calibrated and understood detector. After electricity and cooling were restored to all equipment, at about the time of the last CMS week, recommissioning activities were resumed for all subsystems. On 7 October, DCS shifts began 24/7 to allow subsystems to remain on to facilitate operations. That culminated with the Global Run in November (GriN), which   took place as scheduled during the week of 4 November. The GriN has been the first centrally managed operation since the beginning of LS1, and involved all subdetectors but the Pixel Tracker presently in a lab upstairs. All nights were therefore dedicated to long stable runs with as many subdetectors as possible. Among the many achievements in that week, three items may be highlighted. First, the Strip...

  6. Coordination chemistry and bioactivity of Ni2+, Cu2+, and Zn2+ complexes containing a bidentate NS ligand, β-N-phenyldithiocarbazic acid, and the crystal structure of β-hydroxy-β-phenylmethylene α-phenylimine

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Ahmed Faizal Shamsuddin; Grouse, Karen A.; Yamin, B.M.; Ali, A.M.; Fun, H.-K.

    2003-07-01

    A bidentate ligand (PhDTCH) with NS donor sequence was prepared from the reaction between carbon disulfide and phenylhydrazine in ethanol. Complexes of this ligand with Ni(II), Cu(II) and Zn(II) were synthesized and characterized by elemental analyses, and various physicochemical techniques. The metal complexes were all four coordinated. In an attempt to resolve the crystal structure of PhDTCH, an ethanolic solution, after leaving for a few days gave bright crystals of PhD6, β-hydroxy-β-phenylmethylene α-phenylimine, the crystal structure of which has been resolved. The crystal packing indicated that it is monoclinic with a space group of P21/n. All of the compounds were tested against different bacteria and fungi, and also against leukemic cell lines. All of the compounds showed weak biological properties compared to standard drugs. (author)

  7. Fluorescent detection of apoptotic cells using a family of zinc coordination complexes with selective affinity for membrane surfaces that are enriched with phosphatidylserine.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Bradley D. (University of Notre Dame, Notre Dame, Indiana); Lambert, Timothy N.; Lakshmi, C. (University of Notre Dame, Notre Dame, Indiana); Hanshaw, Roger, G. (University of Notre Dame, Notre Dame, Indiana)

    2005-03-01

    The appearance of phosphatidylserine on the membrane surface of apoptotic cells (Jurkat, CHO, HeLa) is monitored by using a family of bis(Zn{sup 2+}-2,2{prime}-dipicolylamine) coordination compounds with appended fluorescein or biotin groups as reporter elements. The phosphatidylserine affinity group is also conjugated directly to a CdSe/CdS quantum dot to produce a probe suitable for prolonged observation without photobleaching. Apoptosis can be detected under a wide variety of conditions, including variations in temperature, incubation time, and binding media. Binding of each probe appears to be restricted to the cell membrane exterior, because no staining of organelles or internal membranes is observed.

  8. Coordination-organometallic hybrid materials based on the trinuclear M(II)-Ru(II) (M=Ni and Zn) complexes: Synthesis, structural characterization, luminescence and electrochemical properties

    Science.gov (United States)

    Pawal, S. B.; Lolage, S. R.; Chavan, S. S.

    2018-02-01

    A new series of trinuclear complexes of the type Ni[R-C6H4Ndbnd CH(O)C6H3Ctbnd CRu(dppe)2Cl]2 (1a-c) and Zn[Rsbnd C6H4Ndbnd CH(O)C6H3Ctbnd CRu(dppe)2Cl]2 (2a-c) have been prepared from the reaction of trans-[RuCl(dppe)2Ctbnd Csbnd C6H3(OH)(CHO)] (1) with aniline, 4-nitroaniline and 4-methoxyaniline (R1-3) in presence of nickel acetate and zinc acetate in CH2Cl2/MeOH (1:1) mixture. The structural properties of the complexes have been characterized by elemental analyses and spectroscopic techniques viz. FTIR, UV-Visible, 1H NMR and 31P NMR spectral studies. The crystal structure and morphology of the hybrid complexes was investigated with the help of X-ray powder diffraction (XRPD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The thermal properties of 1a-c and 2a-c were studied by thermogravimetric (TG) analysis. The electrochemical behaviour of the complexes reveals that all complexes displayed a quasireversible redox behaviour corresponding to Ru(II)/Ru(III) and Ni(II)/Ni(III) couples for 1a-c and only Ru(II)/Ru(III) couple for 2a-c. All complexes are emissive in solution at room temperature revealing the influence of substituents and solvent polarity on emission properties of the complexes.

  9. New five coordinated supramolecular structured cadmium complex as precursor for CdO nanoparticles: Synthesis, crystal structure, theoretical and 3D Hirshfeld surface analyses

    Science.gov (United States)

    Ghanbari Niyaky, S.; Montazerozohori, M.; Masoudiasl, A.; White, J. M.

    2017-03-01

    In this paper, a combined experimental and theoretical study on a new CdLBr2 complex (L = N1-(2-bromobenzylidene)-N2-(2-((E)-(2-bromobenzylidene) amino)ethyl) ethane-1,2-diamine) synthesized via template method, is described. The crystal structure analysis of the complex indicates that, the Cd(II) ion is centered in a distorted square pyramidal space constructed by three iminic nitrogens of the ligand as well as two bromide anions. More analysis of crystal packing proposed a supramolecular structure stabilized by some non-covalent interactions such as Br⋯Br and Xsbnd H⋯Br (X = N and C) in solid state. Furthermore, 3D Hirshfeld surface analyses and DFT studies were applied for theoretical investigation of the complexes. Theoretical achievements were found in a good agreement with respect to the experimental data. To evaluate the nature of bonding and the strength of the intra and inter-molecular interactions a natural bond orbital (NBO) analysis on the complex structure was performed. Time dependent density functional theory (TD-DFT) was also applied to predict the electronic spectral data of the complex as compared with the experimental ones. CdLBr2 complex as nano-structure compound was also prepared under ultrasonic conditions and characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD). Finally, it was found that the cadmium complex can be used as a suitable precursor for preparation of CdO nanoparticles via calcination process at 600 °C under air atmosphere.

  10. Coordination chemistry of two heavy metals: I, Ligand preferences in lead(II) complexation, toward the development of therapeutic agents for lead poisoning: II, Plutonium solubility and speciation relevant to the environment

    Energy Technology Data Exchange (ETDEWEB)

    Neu, Mary Patricia [Univ. of California, Berkeley, CA (United States)

    1993-11-01

    The coordination chemistry and solution behavior of the toxic ions lead(II) and plutonium(IV, V, VI) have been investigated. The ligand pKas and ligand-lead(II) stability constants of one hydroxamic acid and four thiohydroaxamic acids were determined. Solution thermodynamic results indicate that thiohydroxamic acids are more acidic and slightly better lead chelators than hydroxamates, e.g., N-methylthioaceto-hydroxamic acid, pKa = 5.94, logβ120 = 10.92; acetohydroxamic acid, pKa = 9.34, logβ120 = 9.52. The syntheses of lead complexes of two bulky hydroxamate ligands are presented. The X-ray crystal structures show the lead hydroxamates are di-bridged dimers with irregular five-coordinate geometry about the metal atom and a stereochemically active lone pair of electrons. Molecular orbital calculations of a lead hydroxamate and a highly symmetric pseudo octahedral lead complex were performed. The thermodynamic stability of plutonium(IV) complexes of the siderophore, desferrioxamine B (DFO), and two octadentate derivatives of DFO were investigated using competition spectrophotometric titrations. The stability constant measured for the plutonium(IV) complex of DFO-methylterephthalamide is logβ120 = 41.7. The solubility limited speciation of 242Pu as a function of time in near neutral carbonate solution was measured. Individual solutions of plutonium in a single oxidation state were added to individual solutions at pH = 6.0, T = 30.0, 1.93 mM dissolved carbonate, and sampled over intervals up to 150 days. Plutonium solubility was measured, and speciation was investigated using laser photoacoustic spectroscopy and chemical methods.

  11. Coordination chemistry of two heavy metals: I, Ligand preferences in lead(II) complexation, toward the development of therapeutic agents for lead poisoning: II, Plutonium solubility and speciation relevant to the environment

    International Nuclear Information System (INIS)

    Neu, M.P.

    1993-11-01

    The coordination chemistry and solution behavior of the toxic ions lead(II) and plutonium(IV, V, VI) have been investigated. The ligand pK a s and ligand-lead(II) stability constants of one hydroxamic acid and four thiohydroaxamic acids were determined. Solution thermodynamic results indicate that thiohydroxamic acids are more acidic and slightly better lead chelators than hydroxamates, e.g., N-methylthioaceto-hydroxamic acid, pK a = 5.94, logβ 120 = 10.92; acetohydroxamic acid, pK a = 9.34, logβ l20 = 9.52. The syntheses of lead complexes of two bulky hydroxamate ligands are presented. The X-ray crystal structures show the lead hydroxamates are di-bridged dimers with irregular five-coordinate geometry about the metal atom and a stereochemically active lone pair of electrons. Molecular orbital calculations of a lead hydroxamate and a highly symmetric pseudo octahedral lead complex were performed. The thermodynamic stability of plutonium(IV) complexes of the siderophore, desferrioxamine B (DFO), and two octadentate derivatives of DFO were investigated using competition spectrophotometric titrations. The stability constant measured for the plutonium(IV) complex of DFO-methylterephthalamide is logβ 110 = 41.7. The solubility limited speciation of 242 Pu as a function of time in near neutral carbonate solution was measured. Individual solutions of plutonium in a single oxidation state were added to individual solutions at pH = 6.0, T = 30.0, 1.93 mM dissolved carbonate, and sampled over intervals up to 150 days. Plutonium solubility was measured, and speciation was investigated using laser photoacoustic spectroscopy and chemical methods

  12. A new Kaempferol-based Ru(II) coordination complex, Ru(kaem)Cl(DMSO){sub 3}: Structure and absorption-emission spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Ming Wei; Gang, Jong Back; Kim, Sang Ho; Yoon, Min Young [Gachon University, Sungnam (Korea, Republic of)

    2016-10-15

    Recent interest in developing a new anticancer drug with low side effects has led to the study of the combination of two new anticancer drugs. Although both kaempferol (kaem) and Ru-based metal complexes have not been proven as effective drugs, their unique anticancer activities with reduced side effects have drawn our attention to the need for further studies on their potential in anticancer application. Herein, we report the synthesis, characterization, structure, and spectroscopic properties of a kaem-based Ru (II) complex, RuCl(kaem)(DMSO){sub 3} (1). Because of the presence of a catechol-like functional group in its dihydropyran ring, kaem can strongly bind to the Ru(II) metal center in a basic medium. The molecular structure of the complex was characterized by spectroscopic studies and X-ray crystal structure analysis. In addition, the complex forms a molecular dimer as a result of the cooperative effect of H-bonding and π–π stacking interactions. Moreover, the molecular dimer forms a ladder-like one-dimensional network structure by water mediated H-bonding that further extended into a three-dimensional packing structure. UV–Vis spectroscopy studies of the complex demonstrated the appearance of a strong metal to ligand charge transfer (MLCT) band in the visible region with strong fluorescence emission derived from the MLCT. Further studies are now in progress to demonstrate synergetic anticancer activity.

  13. A new Kaempferol-based Ru(II) coordination complex, Ru(kaem)Cl(DMSO)3: Structure and absorption-emission spectroscopy study

    International Nuclear Information System (INIS)

    Shao, Ming Wei; Gang, Jong Back; Kim, Sang Ho; Yoon, Min Young

    2016-01-01

    Recent interest in developing a new anticancer drug with low side effects has led to the study of the combination of two new anticancer drugs. Although both kaempferol (kaem) and Ru-based metal complexes have not been proven as effective drugs, their unique anticancer activities with reduced side effects have drawn our attention to the need for further studies on their potential in anticancer application. Herein, we report the synthesis, characterization, structure, and spectroscopic properties of a kaem-based Ru (II) complex, RuCl(kaem)(DMSO) 3 (1). Because of the presence of a catechol-like functional group in its dihydropyran ring, kaem can strongly bind to the Ru(II) metal center in a basic medium. The molecular structure of the complex was characterized by spectroscopic studies and X-ray crystal structure analysis. In addition, the complex forms a molecular dimer as a result of the cooperative effect of H-bonding and π–π stacking interactions. Moreover, the molecular dimer forms a ladder-like one-dimensional network structure by water mediated H-bonding that further extended into a three-dimensional packing structure. UV–Vis spectroscopy studies of the complex demonstrated the appearance of a strong metal to ligand charge transfer (MLCT) band in the visible region with strong fluorescence emission derived from the MLCT. Further studies are now in progress to demonstrate synergetic anticancer activity

  14. In vitro study of the insulin-like action of vanadyl-pyrone and -pyridinone complexes with a VO(O4) coordination mode.

    Science.gov (United States)

    Rangel, M; Tamura, A; Fukushima, C; Sakurai, H

    2001-02-01

    The insulin-like action of a novel class of potential insulin-mimetic complexes was investigated in terms of free fatty acid (FFA) release from isolated rat adipocytes. Vanadyl complexes such as VO(ema)2 [(bis(2-ethyl-3-hydroxy-4-pyrone)VO], VO(mpp)2 [bis (3-hydroxy-2-methyl-4(1H)-pyridinone)VO], VO(dmpp)2 [bis(1,2-dimethyl-3-hydroxy-4(1H)-pyridinone)VO] and VO(empp)2 [bis(2-ethyl-3-hydroxy-1-methyl-4(1H)-pyridinone)VO] were tested together with vanadyl sulfate for comparison. The inhibitory effect of the vanadium complexes on FFA release, from rat adipocytes treated with epinephrine, is dependent on concentration and for that reason the results are reported in terms of the IC50 value, the 50% inhibition concentration. The results show that all the complexes have an inhibitory effect on FFA release and that two pyridinone complexes, VO(mpp)2 and VO(empp)2, have a significantly better insulin-mimetic activity than that of vanadyl sulfate.

  15. A new PC(sp(3))P ligand and its coordination chemistry with low-valent iron, cobalt and nickel complexes.

    Science.gov (United States)

    Zhu, Gengyu; Li, Xiaoyan; Xu, Guoqiang; Wang, Lin; Sun, Hongjian

    2014-06-21

    A new PC(sp(3))P ligand N,N'-bis(diphenylphosphino)dipyrromethane [PCH2P] (1) was prepared and its iron, cobalt and nickel chemistry was explored. Two pincer-type complexes [PCHP]Fe(H)(PMe3)2 (2) and [PCHP]Co(PMe3)2 (4) were synthesized in the reaction of with Fe(PMe3)4 and Co(Me)(PMe3)4. 1 reacted with Co(PMe3)4 and Ni(PMe3)4 to afford Co(0) and Ni(0) complexes [PCH2P]Co(PMe3)2 (3) and [PCH2P]Ni(PMe3)2 (5). The structures of complexes 2-5 were determined by X-ray diffraction.

  16. Combination of Scanning Probe Microscopy and Coordination Chemistry: Structural and Electronic Study of Bis(methylbenzimidazolyl)ketone and Its Iron Complex

    NARCIS (Netherlands)

    Folkertsma, Emma; Van Der Lit, Joost; Di Cicco, Francesca; Lutz, Martin; Klein Gebbink, Robertus J. M.; Swart, Ingmar; Moret, Marc-etienne

    2017-01-01

    Here, we report the bulk synthesis of [FeII(BMBIK)Cl2] bearing the redox noninnocent bis(methylbenzimidazolyl)ketone (BMBIK) ligand and the synthesis of the similar complex [FeI(BMBIK)]+ on a Au(111) surface using lateral manipulation at the atomic level. Cyclic voltammetry and scanning tunneling

  17. Reappraisal of the amide coordination mode: solution properties of nickel(II) and copper(II) complexes of ligands involving simultaneously enamine and amide groups

    Energy Technology Data Exchange (ETDEWEB)

    Costes, J.P.; Laurent, J.P.

    1988-09-07

    The behavior of the Cu/sup 2+//L/sub 1/ system in solution was reappraised through the isolation and characterization of the copper(II) complexes involving the ligand L/sub 1/ in different states of protonation. Also included in the study are the homologous nickel(II) complexes and the copper(II) and nickel(II) complexes of related ligands L/sub 2/ and L/sub 3/. L/sub 1/ is the ligand 3,8-dimethyl-4,7-diazadeca-2,8-diene-1,10-diamide synthesized from acetoacetamide and 1,2,diaminoethane. L/sub 2/ and L/sub 3/ were similarly synthesized using acetoacetanilide and ethylacetoacetate instead of acetoamide. The complexes were studied by ESR and visible spectroscopy, and the data demonstrate that in all cases not only the ligand L/sub 3/ but also L/sub 1/ and L/sub 2/ are in the enamine form, and the first step of the protonation process concerns the proton of the enamine functions and not those of the amide group. 8 references, 2 tables.

  18. Prophage induction and mutagenicity of a series of anti-tumour platinum(II) and platinum(IV) co-ordination complexes

    NARCIS (Netherlands)

    Mattern, I.E.; Cocchiarella, L.; Kralingen, C.G. van; Lohman, P.H.M.

    1982-01-01

    Eleven platinum compounds with nitrogen donor ligands, previously tested for anti-tumour activity were studied for induction of prophage lambda and for mutagenicity in the Ames assay, with various strains of Salmonella. The compounds included cis and trans isomers of Pt(II) and Pt(IV) complexes and

  19. Syntheses, crystal structures and antimicrobial activities of 6-coordinate antimony(III) complexes with tridentate 2-acetylpyridine thiosemicarbazone, bis(thiosemicarbazone) and semicarbazone ligands.

    Science.gov (United States)

    Kasuga, Noriko Chikaraishi; Onodera, Kuniaki; Nakano, Saori; Hayashi, Kunihiko; Nomiya, Kenji

    2006-07-01

    Five novel antimony(III) complexes with the mono- and bis(thiosemicarbazone) ligands of 2N1S or 4N2S donor atoms, N'-[1-(2-pyridyl)ethylidene]morpholine-4-carbothiohydrazide (Hmtsc, L1) and bis[N'-[1-(2-pyridyl)ethylidene

  20. Synthesis and spectroscopy of clay intercalated Cu(II) bio-monomer complexes: coordination of Cu(II) with purines and nucleotides

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Leeman, H.; Schoonheydt, R.A.

    1999-01-01

    The spectroscopic properties of Cu(bio-monomer)nm+ complexes [BM=bio-monomer (purine, adenine, guanine, hypoxanthine, 5-ADP and 5-GMP)] in saponite clays have been investigated by diffuse reflectance spectroscopy (DRS) in the UV-Vis-NIR region and electron paramagnetic resonance (EPR) at X-band.

  1. Computational Analysis of a Zn-Bound Tris(imidazolyl) Calix[6]arene Aqua Complex: Toward Incorporating Second-Coordination Sphere Effects into Carbonic Anhydrase Biomimetics.

    Science.gov (United States)

    Koziol, Lucas; Essiz, Sebnem G; Wong, Sergio E; Lau, Edmond Y; Valdez, Carlos A; Satcher, Joe H; Aines, Roger D; Lightstone, Felice C

    2013-03-12

    Molecular dynamics simulations and quantum-mechanical calculations were performed to characterize a supramolecular tris(imidazolyl) calix[6]arene Zn(2+) aqua complex, as a biomimetic model for the catalyzed hydration of carbon dioxide to bicarbonate, H2O + CO2 → H(+) + HCO3(-). On the basis of potential-of-mean-force (PMF) calculations, stable conformations had distorted 3-fold symmetry and supported either one or zero encapsulated water molecules. The conformation with an encapsulated water molecule is calculated to be lower in free energy than the conformation with an empty cavity (ΔG = 1.2 kcal/mol) and is the calculated free-energy minimum in solution. CO2 molecule partitioning into the cavity is shown to be very facile, proceeding with a barrier of 1.6 kcal/mol from a weak encounter complex which stabilizes the species by about 1.0 kcal/mol. The stabilization energy of CO2 is calculated to be larger than that of H2O (ΔΔG = 1.4 kcal/mol), suggesting that the complex will preferentially encapsulate CO2 in solution. In contrast, the PMF for a bicarbonate anion entering the cavity is calculated to be repulsive in all nonbonding regions of the cavity, due to the diameter of the calix[6]arene walls. Geometry optimization of the Zn-bound hydroxide complex with an encapsulated CO2 molecule showed that multiple noncovalent interactions direct the reactants into optimal position for nucleophilic addition to occur. The calixarene complex is a structural mimic of the hydrophilic/hydrophobic divide in the enzyme, providing a functional effect for CO2 addition in the catalytic cycle. The results show that Zn-binding calix[6]arene scaffolds can be potential synthetic biomimetics for CO2 hydration catalysis, both in terms of preferentially encapsulating CO2 from solution and by spatially fixing the reactive species inside the cavity.

  2. Reversible Coordination of Boron-, Aluminum-, Zinc-, Magnesium-, and Calcium-Hydrogen Bonds to Bent {CuL2} Fragments: Heavy σ Complexes of the Lightest Coinage Metal.

    Science.gov (United States)

    Hicken, Alexandra; White, Andrew J P; Crimmin, Mark R

    2017-08-07

    A series of copper(I) complexes bearing electron-deficient β-diketiminate ligands have been prepared. The study includes [{{ArNC(CR 3 )} 2 CH}Cu(η 2 -toluene) n ] (Ar = Mes, R = F, n = 0.5, [1 2 ·tol]; Ar = C 6 F 5 , R = Me, n = 1, [2·tol]; Ar = 2,6-Cl 2 C 6 H 3 , R = H, n = 0.5, [3 2 ·tol]). Reactions of [1-3 n ·tol] with boranes, alanes, a zinc hydride, a magnesium hydride, and a calcium hydride generate the corresponding σ complexes ([1-3·B], [3·B'], [3·Al], [3·Al'], [1-3·Zn], [1·Mg], and [1·Ca]). These species all form reversibly, being in equilibrium with the arene solvates in solution. With the exception of the calcium complex, the complexes have all been characterized by single-crystal X-ray diffraction studies. In solution, the σ-hydride of the aluminum, zinc, magnesium, and calcium derivatives resonates between -0.12 and -1.77 ppm (C 6 D 6 or toluene-d 8 , 193-298 K). For the σ-borane complexes, the hydrides are observed as a single resonance between 2 and 3.5 ppm (C 6 D 6 , 298 K) and bridging and terminal hydrides rapidly exchange on the NMR time scale even at 193 K. Quantification of the solution dynamics by van't Hoff analysis yields expectedly small values of ΔH° and negative values of ΔS° consistent with weak binding and a reversible process that does not involve aggregation of the copper species. The donor-acceptor complexes can be rationalized in terms of the Dewar-Chatt-Duncanson model. Density functional theory calculations show that the donation of σ-M-H (or E-H) electrons into the 4s-based orbital (LUMO or LUMO+1) of the copper fragment is accompanied by weak back-donation from a d xz -based orbital (HOMO or HOMO-1) into the σ*-M-H (or E-H) orbital.

  3. The coordination complex structures and hydrogen bonding in the three-dimensional alkaline earth metal salts (Mg, Ca, Sr and Ba) of (4-aminophenyl)arsonic acid.

    Science.gov (United States)

    Smith, Graham; Wermuth, Urs D

    2017-01-01

    (4-Aminophenyl)arsonic acid (p-arsanilic acid) is used as an antihelminth in veterinary applications and was earlier used in the monosodium salt dihydrate form as the antisyphilitic drug atoxyl. Examples of complexes with this acid are rare. The structures of the alkaline earth metal (Mg, Ca, Sr and Ba) complexes with (4-aminophenyl)arsonic acid (p-arsanilic acid) have been determined, viz. hexaaquamagnesium bis[hydrogen (4-aminophenyl)arsonate] tetrahydrate, [Mg(H 2 O) 6 ](C 6 H 7 AsNO 3 )·4H 2 O, (I), catena-poly[[[diaquacalcium]-bis[μ 2 -hydrogen (4-aminophenyl)arsonato-κ 2 O:O']-[diaquacalcium]-bis[μ 2 -hydrogen (4-aminophenyl)arsonato-κ 2 O:O

  4. Large Easy-Plane Magnetic Anisotropy in a Three-Coordinate Cobalt(II) Complex [Li(THF)4][Co(NPh2)3].

    Science.gov (United States)

    Deng, Yi-Fei; Wang, Zhenxing; Ouyang, Zhong-Wen; Yin, Bing; Zheng, Zhiping; Zheng, Yan-Zhen

    2016-10-10

    Magnetic anisotropy is the key element in the construction of single-ion magnets, a kind of nanomagnets for high-density information storage. This works describes an unusual large easy-plane magnetic anisotropy (with a zero-field splitting parameter D of +40.2 cm -1 ), mainly arising from the second-order spin-orbit coupling effect in a trigonal-planar Co II complex [Li(THF) 4 ][Co(NPh 2 ) 3 ], revealed by combined studies of magnetism, high frequency/field electron paramagnetic resonance spectroscopy, and ab initio calculations. Meanwhile, the field-induced slow magnetic relaxation in this complex was mainly attributed to the Raman process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Atom transfer as a preparative tool in coordination chemistry. Synthesis and characterization of Cr(V) nitrido complexes of bidentate ligands

    DEFF Research Database (Denmark)

    Birk, Torben; Bendix, Jesper

    2003-01-01

    The transfer of a terminal nitrido ligand from MnV(N)(salen) to Cr(III) complexes is explored as a new preparative route to CrV nitrido complexes. Reaction of MnV(N)(salen) with labile CrCl3(THF)3 in acetonitrile solution precipitate [Mn(Cl)(salen)]·(CH3CN) and yields a solution containing......) crystallizes as green rhombs in the orthorhombic space group Pbca with cell parameters a = 14.6940(6) Å, b = 16.4570(18) Å, c  =19.890(3) Å, V = 4809.8(8) Å3, Z = 8. Cr(N)(pyr-dtc)2 (3) crystallizes as orange prisms in the monoclinic space group P21/c with cell parameters a = 14.8592(14) Å, b = 8.5575(5) Å, c...

  6. Coordination versatility of N2O4 polydentate hydrazonic ligand in Zn(II, Cu(II, Ni(II, Co(II, Mn(II and Pd(II complexes and antimicrobial evaluation

    Directory of Open Access Journals (Sweden)

    Fathy A. El-Saied

    2017-12-01

    Full Text Available New polydentate hydrazone ligand, was synthesized by the condensation of 1,5-dimethyl-3-oxo-2-phenylpyrazole-4-carbaldehyde with adipodihydrazide. The structure of the synthesized ligand, N′1,N′6-bis((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl methylene adipohydrazide was elucidated by various analytical and spectroscopic techniques. The reactions of the ligand with zinc(II, copper(II, nickel(II, cobalt(II, manganese(II and palladium(II salts afforded homobinuclear metal complexes. Characterization and structure elucidation of the prepared complexes were achieved using different analytical and spectroscopic techniques. The analyses data indicated that this ligand behaved as N2O4 dibasic hexadentate ligand bonded covalency to the metal ions through the enolic carbonyl oxygen of hydrazide moiety and coordinated via carbonyl oxygen of antipyrine moiety and azomethine nitrogen atoms forming distorted octahedral geometry around the metal ions. The ESR spectra of copper(II complexes (3 and (4 showed an axial symmetry with g||>g⊥>ge, indicating distorted octahedral structure and presence of the unpaired electron in d(x2−y2 orbital. The microbicide studies of the ligand and its metal complexes (2, (3, (4, (5, (8, (11 and (13 showed that, all these complexes exhibit moderate to mild inhibitory effects on B. subtilis, E. coli while complexes (2, (3, (4 and (13 exhibit moderate to mild inhibitory effects on A. niger. Keywords: Hexadentate, Hydrazone, Antipyrine, ESR, Adipohydrazide, Microbicide

  7. Complex Interplay between FleQ, Cyclic Diguanylate and Multiple σ Factors Coordinately Regulates Flagellar Motility and Biofilm Development in Pseudomonas putida.

    Directory of Open Access Journals (Sweden)

    Alicia Jiménez-Fernández

    Full Text Available Most bacteria alternate between a free living planktonic lifestyle and the formation of structured surface-associated communities named biofilms. The transition between these two lifestyles requires a precise and timely regulation of the factors involved in each of the stages that has been likened to a developmental process. Here we characterize the involvement of the transcriptional regulator FleQ and the second messenger cyclic diguanylate in the coordinate regulation of multiple functions related to motility and surface colonization in Pseudomonas putida. Disruption of fleQ caused strong defects in flagellar motility, biofilm formation and surface attachment, and the ability of this mutation to suppress multiple biofilm-related phenotypes associated to cyclic diguanylate overproduction suggests that FleQ mediates cyclic diguanylate signaling critical to biofilm growth. We have constructed a library containing 94 promoters potentially involved in motility and biofilm development fused to gfp and lacZ, screened this library for FleQ and cyclic diguanylate regulation, and assessed the involvement of alternative σ factors σN and FliA in the transcription of FleQ-regulated promoters. Our results suggest a dual mode of action for FleQ. Low cyclic diguanylate levels favor FleQ interaction with σN-dependent promoters to activate the flagellar cascade, encompassing the flagellar cluster and additional genes involved in cyclic diguanylate metabolism, signal transduction and gene regulation. On the other hand, characterization of the FleQ-regulated σN- and FliA-independent PlapA and PbcsD promoters revealed two disparate regulatory mechanisms leading to a similar outcome: the synthesis of biofilm matrix components in response to increased cyclic diguanylate levels.

  8. (15)N NMR spectroscopy unambiguously establishes the coordination mode of the diimine linker 2-(2'-pyridyl)pyrimidine-4-carboxylic acid (cppH) in Ru(ii) complexes.

    Science.gov (United States)

    Battistin, Federica; Balducci, Gabriele; Demitri, Nicola; Iengo, Elisabetta; Milani, Barbara; Alessio, Enzo

    2015-09-21

    We investigated the reactivity of three Ru(ii) precursors -trans,cis,cis-[RuCl2(CO)2(dmso-O)2], cis,fac-[RuCl2(dmso-O)(dmso-S)3], and trans-[RuCl2(dmso-S)4] - towards the diimine linker 2-(2'-pyridyl)pyrimidine-4-carboxylic acid (cppH) or its parent compound 4-methyl-2-(2'-pyridyl)pyrimidine ligand (mpp), in which a methyl group replaces the carboxylic group on the pyrimidine ring. In principle, both cppH and mpp can originate linkage isomers, depending on how the pyrimidine ring binds to ruthenium through the nitrogen atom ortho (N(o)) or para (N(p)) to the group in position 4. The principal aim of this work was to establish a spectroscopic fingerprint for distinguishing the coordination mode of cppH/mpp also in the absence of an X-ray structural characterization. By virtue of the new complexes described here, together with the others previously reported by us, we successfully recorded {(1)H,(15)N}-HMBC NMR spectra at natural abundance of the (15)N isotope on a consistent number of fully characterized Ru(ii)-cppH/mpp compounds, most of them being stereoisomers and/or linkage isomers. Thus, we found that (15)N NMR chemical shifts unambiguously establish the binding mode of cppH and mpp - either through N(o) or N(p)- and can be conveniently applied also in the absence of the X-ray structure. In fact, coordination of cppH to Ru(ii) induces a marked upfield shift for the resonance of the N atoms directly bound to the metal, with coordination induced shifts (CIS) ranging from ca.-45 to -75 ppm, depending on the complex, whereas the unbound N atom resonates at a frequency similar to that of the free ligand. Similar results were found for the complexes of mpp. This work confirmed our previous finding that cppH has no binding preference, whereas mpp binds exclusively through N(p). Interestingly, the two cppH linkage isomers trans,cis-[RuCl2(CO)2(cppH-κN(p))] (5) and trans,cis-[RuCl2(CO)2(cppH-κN(o))] (6) were easily obtained in pure form by exploiting their different

  9. Coordination chemistry of bis(delta-camphorquinone dioximato)nickel(II) and -palladium(II). Reactions and structural studies of some M/sub 3/Ag/sub 3/ cluster complexes of camphorquinone dioxime

    Energy Technology Data Exchange (ETDEWEB)

    Ma, M.S.; Angelici, R.J.; Powell, D.; Jacobson, R.A.

    1980-01-01

    Reactions of AgNO/sub 3/ with Ni(delta-HCQD)/sub 2/ or Pd(delta-HCQD)/sub 2/, where delta-HCQD/sup -/ is delta-camphorquinone dioximato, yielded the hexanuclear metal cluster complexes (Ni(delta-HCQD)/sub 2/Ag)/sub 3/ x 2.5CHCl/sub 3/, Ni-Ag, and (Pd(delta-HCQD)/sub 2/Ag)/sub 3/ x 2CHCl/sub 3/, Pd-Ag, respectively. X-ray crystallographic studies performed on both complexes showed them to belong to space group P2/sub 1/2/sub 1/2/sub 1/. The unit cell dimensions of Ni-Ag are a = 15.990 (5) A, b = 38.44 (1) A, c = 13.437 (5) A, V = 8260.97 A/sup 3/, and Z = 4 while those of Pd-Ag are a = 16.110 (6), b = 38.92 (1), c = 13.393 (3) A, V = 8395.55 A/sup 3/, and Z = 4. Block-diagonal least-squares refinement of 3021 observed reflections for Ni-Ag and 6112 for Pd-Ag converged to R/sub F/ = 10.7 and 11.4 (R/sub w/ = 12.7 and 15.0) for the Ni-Ag and Pd-Ag structures, respectively. Their structures indicate that each hexanuclear molecule consists of three individual M(delta-HCQD)/sub 2//sup -/ units which act as multidentate ligands coordinating to a linear chain of three silver atoms. The coordination geometry around each M ion in the M(delta-HCQD)/sub 2//sup -/ units is square planar, and the delta-HCQD/sup -/ ligands are coordinated to M via N and O atoms. The Ag in the center of the molecule is coordinated to six O atoms with average Ag-O distances of 2.49 (3) and 2.45 (2) A for Ni-Ag and Pg-Ag, respectively. The two silver atoms at the ends of the chain are each coordinated to three nitrogen atoms from the M(delta-HCQD)/sub 2//sup -/ units with average Ag-N distances of 2.20 (4) and 2.27 (3) A, respectively. The Ag-Ag distances, 3.059 (5) and 3.052 (5) A in Ni-Ag and 3.173 (3) and 3.179 (3) A in Pd-Ag, are somewhat longer than those (2.89 A) in Ag metal and indicate that there are Ag-Ag interactions along the linear chains. The bis(pyridine) adduct of Ni(delta-HCQD)/sub 2/ was also prepared. A proposed structure for this complex is based on the similarity of its ir

  10. TECHNICAL COORDINATION

    CERN Multimedia

    A. Ball

    Shutdown critical path: progress and prospects The 2008-09 CMS shutdown is proceeding as intended.  The first two phases, in which the dominant activity (besides heavy logistics) was maintenance and repair of the barrel muon and alignment systems on all wheels and disks (but particularly YB0), have been finished successfully and on time. The yoke wheels at both ends are once again closed over the vactank. Phase 3 is in full swing and has reached maximum complexity, with work-intensity and associated risks similar those encountered in summer 2008. The status going into this CMS week is that the forward pixel tracker at the +z end (FPIX+) has been extracted and transported for maintenance, while the installation of preshower ES+, taking place in parallel, has reached the stage where the active “dee” elements are installed and the drum structures have just been moved back along the beampipe and re-mated to the electromagnetic endcaps. The phase 3 activity requires the large &l...

  11. Late First-Row Transition-Metal Complexes Containing a 2-Pyridylmethyl Pendant-Armed 15-Membered Macrocyclic Ligand. Field-Induced Slow Magnetic Relaxation in a Seven-Coordinate Cobalt(II) Compound.

    Science.gov (United States)

    Antal, Peter; Drahoš, Bohuslav; Herchel, Radovan; Trávníček, Zdeněk

    2016-06-20

    The 2-pyridylmethyl N-pendant-armed heptadentate macrocyclic ligand {3,12-bis(2-methylpyridine)-3,12,18-triaza-6,9-dioxabicyclo[12.3.1]octadeca-1,14,16-triene = L} and [M(L)](ClO4)2 complexes, where M = Mn(II) (1), Fe(II) (2), Co(II) (3), Ni(II) (4), and Cu(II) (5), were prepared and thoroughly characterized, including elucidation of X-ray structures of all the compounds studied. The complexes 1-5 crystallize in non-centrosymmetric Sohncke space groups as racemic compounds. The coordination numbers of 7, 6 + 1, and 5 were found in complexes 1-3, 4, and 5, respectively, with a distorted pentagonal bipyramidal (1-4) or square pyramidal (5) geometry. On the basis of the magnetic susceptibility experiments, a large axial zero-field splitting (ZFS) was found for 2, 3, and 4 (D(Fe) = -7.4(2) cm(-1), D(Co) = 34(1) cm(-1), and D(Ni) = -12.8(1) cm(-1), respectively) together with a rhombic ZFS (E/D = 0.136(3)) for 4. Despite the easy plane anisotropy (D > 0, E/D = 0) in 3, the slow relaxation of the magnetization below 8 K was observed and analyzed either with Orbach relaxation mechanism (the relaxation time τ0 = 9.90 × 10(-10) s and spin reversal barrier Ueff = 24.3 K (16.9 cm(-1))) or with Raman relaxation mechanism (C = 2.12 × 10(-5) and n = 2.84). Therefore, compound 3 enlarges the small family of field-induced single-molecule magnets with pentagonal-bipyramidal chromophore. The cyclic voltammetry in acetonitrile revealed reversible redox processes in 1-3 and 5, except for the Ni(II) complex 4, where a quasi-reversible process was dominantly observed. Presence of the two 2-pyridylmethyl pendant arms in L with a stronger σ-donor/π-acceptor ability had a great impact on the properties of all the complexes (1-5), concretely: (i) strong pyridine-metal bonds provided slight axial compression of the coordination sphere, (ii) substantial changes in magnetic anisotropy, and (iii) stabilization of lower oxidation states.

  12. Probing the lowest coordination number of dianionic platinum-cyanide complexes in the gas phase: Dynamics of the charge dissociation process

    DEFF Research Database (Denmark)

    Bojesen, G; Hvelplund, P; Jørgensen, Thomas J. D.

    2000-01-01

    Low-energy and high-energy collision induced dissociation techniques are used to study the dissociation behavior of the gaseous Pt(CN)(6)(2-) and Pt(CN)(4)(2-) dianion complexes in order to probe the smallest stable dianion complex. Loss of neutral molecules from Pt(CN)(6)(2-) occurs resulting.......e., Pt(CN)(n)(-) (n=1-6). The kinetic energy released in processes where monoanions are formed is much lower than the barrier height for the reverse reaction (>1.5 eV), which indicates that electron detachment is involved, e.g., Pt(CN)(3)(-) and CN- are not formed in the same dynamical process from Pt......(CN)(4)(2-), or that the dynamics of the dissociation process is slow. For comparison, the Ru(bipy)(3)(2+)*--> [Ru(bipy)(2)-H](+)+bipyH(+) reaction is associated with a kinetic-energy release of similar to0.3 eV (bipy=2,2(')-bipyridine). (C) 2000 American Institute of Physics. [S0021-9606(00)00240-3]....

  13. Coordination studies of 1,2-bis(diphenylphosphinoethane with di-μ-hydroxo dinuclear complexes of tungsten(IV and molybdenum(IV

    Directory of Open Access Journals (Sweden)

    Minato Makoto

    2016-01-01

    Full Text Available The new trifluoroethoxo phosphine complexes [Cp2M(η1-dppe(CF3CH2O]+ and [Cp2(CF3CH2OM(μ-dppeMCp2(CF3CH2O]2+ (M = Mo or W, Cp = η-C5H5 and dppe = Ph2PCH2CH2PPh2 have been prepared by reaction of cationic di-μ-hydroxo dinuclear complex of molybdenocene or tungstenocene [Cp2M(μ-OH2MCp2]2+ with dppe. From the 1H and 31P NMR data, the configurations of the products could be assigned. Furtheremore, X-ray crystallography was used to definitively identify one of the product [Cp2(CF3CH2OMo(μ-dppeMoCp2(CF3CH2O]2+, which crystallizes in space group P21/c(#14 with a = 12.230(5 Å, b = 11.149(5 Å, c = 28.966(7 Å, β = 101.07(3°, V = 3876(2 Å3, and Z = 2. It was ascertained that the amount of dppe added to the reaction mixture could influence the product distribution. A mechanism involving initial replacement of the hydroxo ligand by the alkoxo group followed by nucleophilic attack of the phosphine is proposed on the basis of the reaction profile.

  14. Shared and differentiated motor skill impairments in children with dyslexia and/or attention deficit disorder: From simple to complex sequential coordination.

    Science.gov (United States)

    Marchand-Krynski, Marie-Ève; Morin-Moncet, Olivier; Bélanger, Anne-Marie; Beauchamp, Miriam H; Leonard, Gabriel

    2017-01-01

    Dyslexia and Attention deficit disorder (AD) are prevalent neurodevelopmental conditions in children and adolescents. They have high comorbidity rates and have both been associated with motor difficulties. Little is known, however, about what is shared or differentiated in dyslexia and AD in terms of motor abilities. Even when motor skill problems are identified, few studies have used the same measurement tools, resulting in inconstant findings. The present study assessed increasingly complex gross motor skills in children and adolescents with dyslexia, AD, and with both Dyslexia and AD. Our results suggest normal performance on simple motor-speed tests, whereas all three groups share a common impairment on unimanual and bimanual sequential motor tasks. Children in these groups generally improve with practice to the same level as normal subjects, though they make more errors. In addition, children with AD are the most impaired on complex bimanual out-of-phase movements and with manual dexterity. These latter findings are examined in light of the Multiple Deficit Model.

  15. Shared and differentiated motor skill impairments in children with dyslexia and/or attention deficit disorder: From simple to complex sequential coordination.

    Directory of Open Access Journals (Sweden)

    Marie-Ève Marchand-Krynski

    Full Text Available Dyslexia and Attention deficit disorder (AD are prevalent neurodevelopmental conditions in children and adolescents. They have high comorbidity rates and have both been associated with motor difficulties. Little is known, however, about what is shared or differentiated in dyslexia and AD in terms of motor abilities. Even when motor skill problems are identified, few studies have used the same measurement tools, resulting in inconstant findings. The present study assessed increasingly complex gross motor skills in children and adolescents with dyslexia, AD, and with both Dyslexia and AD. Our results suggest normal performance on simple motor-speed tests, whereas all three groups share a common impairment on unimanual and bimanual sequential motor tasks. Children in these groups generally improve with practice to the same level as normal subjects, though they make more errors. In addition, children with AD are the most impaired on complex bimanual out-of-phase movements and with manual dexterity. These latter findings are examined in light of the Multiple Deficit Model.

  16. The influence of intramolecular coordination on the aggregation of sodium phenolate complexes. X-ray structures of [NaOC6H4(CH2NMe2)-2]6 and [Na(OC6H2(CH2NMe2)2-2,6-Me-4)(HOC6H2NMe2)2-2,6-Me-4)]2

    NARCIS (Netherlands)

    Koten, G. van; Hogerheide, M.P.; Ringelberg, S.N.; Janssen, M.D.; Boersma, J.; Spek, A.L.

    1996-01-01

    The structural characterization of two new sodium phenolate complexes, containing ortho-amino substituents, enables the influence of intramolecular coordination on the aggregation of sodium phenolate complexes to be determined. Crystals of hexameric [NaOC6H4(CH2NMe2)-2]6 (1a) are monoclinic, space

  17. Long-time solution of the time-dependent Schroedinger equation for an atom in an electromagnetic field using complex coordinate contours

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Liang; Vanroose, Wim; Reps, Brian; Rescigno, Thomas N.; McCurdy, C. William

    2009-09-08

    We demonstrate that exterior complex scaling (ECS) can be used to impose outgoing wave boundary conditions exactly on solutions of the time-dependent Schrodinger equation for atoms in intense electromagnetic pulses using finite grid methods. The procedure is formally exact when applied in the appropriate gauge and is demonstrated in a calculation of high harmonic generation in which multiphoton resonances are seen for long pulse durations. However, we also demonstrate that while the application of ECS in this way is formally exact, numerical error can appear for long time propagations that can only be controlled by extending the finite grid. A mathematical analysis of the origins of that numerical error, illustrated with an analytically solvable model, is also given.

  18. Coordinators in Safaliba

    OpenAIRE

    Bodua-Mango, Kenneth

    2012-01-01

    This study examines the Safaliba coordinators „ní‟ / „aní‟, „á‟, „ka‟, „chɛ‟ and „bíí‟ in their naturally occurring environments. Safaliba is a Gur language spoken by some 5000 -7000 people in the north-western part of Ghana. The main areas of study include the syntactic categories that each coordinator can coordinate, the semantic properties of each of the coordinators and the pragmatic effect that the use of theses coordinators can have. Combinations of the individual coordinators calle...

  19. Controlled synthesis, formation mechanism, and carbon oxidation properties of Ho{sub 2}Cu{sub 2}O{sub 5} nanoplates prepared with a coordination-complex method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Rui [School of Resources and Materials, Northeastern University at Qinhuangdao 066004 (China); School of Metallurgy, Northeastern University, Shenyang 110004 (China); You, Junhua [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870 (China); Han, Fei; Li, Chaoyang; Zheng, Guiyuan; Xiao, Weicheng [School of Resources and Materials, Northeastern University at Qinhuangdao 066004 (China); Liu, Xuanwen, E-mail: lxw@mail.neuq.edu.cn [School of Resources and Materials, Northeastern University at Qinhuangdao 066004 (China); School of Metallurgy, Northeastern University, Shenyang 110004 (China)

    2017-02-28

    Highlights: • The crystallization mechanism relies on Ho{sup 3+} and Cu{sup 2+} diffusion. • The Ho{sub 2}Cu{sub 2}O{sub 5} particles are refined by the coordination complex method under N{sub 2} environment. • The catalytic oxidation activity of Ho{sub 2}Cu{sub 2}O{sub 5} samples for carbon is enhanced. - Abstract: Ho{sub 2}Cu{sub 2}O{sub 5} nanoplates with perovskite structures were synthesized via a simple solution method (SSM) and a coordination-complex method (CCM) using [HoCu(3,4-pdc){sub 2}(OAc)(H{sub 2}O){sub 3}]·8H{sub 2}O (L = 3,4-pyridinedicarboxylic acid) as a precursor. The CCM was also performed in an N{sub 2} environment (CCMN) under various calcination conditions. The crystallization processes were characterized using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Ho{sub 2}Cu{sub 2}O{sub 5} formed through the diffusion of CuO into Ho{sub 2}O{sub 3} particles. Cu{sup 2+} diffused faster than Ho{sup 3+} during this process. The initial products of CCMN (along with the thermal decomposition products) were initially laminarized in the N{sub 2} atmosphere, which prevented the growth of CuO particles and decreased the size of the Ho{sub 2}Cu{sub 2}O{sub 5} particles. The final Ho{sub 2}Cu{sub 2}O{sub 5} particles from CCMN had a nanoplate morphology with an average thickness of 75 nm. The decomposition of organic molecules and protection from N{sub 2} played important roles in determining the morphology of the resulting Ho{sub 2}Cu{sub 2}O{sub 5}. The catalytic oxidation activity of Ho{sub 2}Cu{sub 2}O{sub 5} samples for carbon was characterized using a specific surface area measurement and thermogravimetric analysis, which revealed that the samples produced by CCMN had the highest catalytic activity.

  20. Fluorescent zinc–terpyridine complex containing coordinated ...

    Indian Academy of Sciences (India)

    Unknown

    Mattay J (eds) 1990 Topics in current chem. 158 (Berlin: Springer-Verlag). 11. DeArmond M K and Carlin C M 1981 Coord Chem. Rev. 36 325. 12. Kutal C 1990 Coord. Chem. Rev. 99 213. 13. Kemlo J A and Shepherd T M 1977 Chem. Phys. Letts. 47158; (b) Rurack R, Resch U. Senonerk M and Dachne S 1993 J. Fluoresc.

  1. Low temperature X-ray structure analyses combined with NBO studies of a new heteroleptic octa-coordinated Holmium(III) complex with N,N,N-tridentate hydrazono-phthalazine-type ligand

    Science.gov (United States)

    Soliman, Saied M.; El-Faham, Ayman

    2018-04-01

    The new heteroleptic [HoL(H2O)5]Br3 complex, L is hydrazono-phthalazine ligand, is synthesized and its molecular structure aspects were analyzed using single crystal X-ray structure (SCXRD), Hirshfeld (HF) analysis, quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) method. The SCXRD showed that the Ho is octa-coordinated with one N,N,N-tridentate ligand L and five water molecules. The HF analysis is used to analyze the molecular packing in the [HoL(H2O)5]Br3crystal structure. The complex cations are connected via strong Osbnd H⋯Br and Nsbnd H⋯Br H-bonding interactions which have greater importance than the Csbnd H⋯Br contacts. Also, all the Hosbnd N and Hosbnd O bonds have the characteristics of closed shell interactions using QTAIM. The natural orbitals included in these interactions were analyzed using NBO method. The alpha LP*(8)Ho and beta LP*(4)Ho which have mainly s-orbital characters are the most important anti-bonding natural orbitals included in all Ho-N and Hosbnd O bonds. The rest of the Ho anti-bonding orbitals which have either p or d-orbital characters shared partially in the Ho-ligands interactions. Natural charges analysis revealed the presence of significant amount of electron density (0.9225-0.9300 e) transferred from the ligands to Ho (2.0700-2.0775 e). Spherical spin density with ∼4.0 e is predicted over the Ho atom.

  2. ANIONS FUNCTIONS IN TRANSITION METALS COORDINATION COMPOUNDS

    Directory of Open Access Journals (Sweden)

    T. V. Koksharova

    2016-04-01

    Full Text Available The effect of anions on the structure and properties of coordination compounds of transition metals has been discussed. The examples of changes in the composition of the formed complexes by replacement of the anion are given: metal ratio to a neutral ligand, the composition of the inner sphere, the direction of template synthesis. Anions can determine the presence of isomers in complexes with different ligands. Examples of conformational, ionization isomerism, inner sphere bond isomerization are given. The nature of the coordination polyhedron is highly sensitive to the replacement of the anion too. Examples of coordination compounds where the anion change causes a change in coordination capacity of neutral ligands and the strength of their bonds with the metal, coordination number and geometry of the inner sphere, the organization of molecular structures (the structure of the hydrogen bond networks and the degree of polymerization, crystal packing. The anions significantly affect the binding of the solvent molecules, complexes magnetic and luminescent properties, they can change the compound color, the mechanisms of thermolysis. Anions make a very noticeable influence on possible redox processes following the complexation in some cases. Anions in the coordination sphere can change catalytic and biochemical processes as well as the ways of interaction of metal ions with drugs.

  3. An Electronic Marketplace: Agent-based Coordination Models for Online Auctions

    NARCIS (Netherlands)

    Morali, A.; Diaz, J.F.; Rueda, C.; Varela, L.; Varela, C.A.; Buss, A.A.

    2005-01-01

    Different coordination models exist for managing concurrency in complex distributed systems, for example, direct interaction, tuple spaces, hierarchical structures, and publish-and-subscribe mechanisms. Online auctions are complex distributed systems, where the choice of coordination model can

  4. Machine Learning of Biomolecular Reaction Coordinates.

    Science.gov (United States)

    Brandt, Simon; Sittel, Florian; Ernst, Matthias; Stock, Gerhard

    2018-04-09

    We present a systematic approach to reduce the dimensionality of a complex molecular system. Starting with a data set of molecular coordinates (obtained from experiment or simulation) and an associated set of metastable conformational states (obtained from clustering the data), a supervised machine learning model is trained to assign unknown molecular structures to the set of metastable states. In this way, the model learns to determine the features of the molecular coordinates that are most important to discriminate the states. Using a new algorithm that exploits this feature importance via an iterative exclusion principle, we identify the essential internal coordinates (such as specific interatomic distances or dihedral angles) of the system, which are shown to represent versatile reaction coordinates that account for the dynamics of the slow degrees of freedom and explain the mechanism of the underlying processes. Moreover, these coordinates give rise to a free energy landscape that may reveal previously hidden intermediate states of the system.

  5. Polymeric coordination compounds

    Indian Academy of Sciences (India)

    Administrator

    Ce(dipic)3Sr(dipicH2)(OH2)3·5H2O (4) (dipicH2 – dipicolinic acid) exhibits 1-D polymeric chain structure, built up of alternating nine coordinate Ce and eight coordinate. Sr polyhedra. The analogous Ce–Ba compound (5) exhibits a polymeric chain built up of nine coordinate Ba units only, arranged in a hexagonal lattice.

  6. Traceability and uncertainty estimation in coordinate metrology

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Savio, Enrico; De Chiffre, Leonardo

    2001-01-01

    National and international standards have defined performance verification procedures for coordinate measuring machines (CMMs) that typically involve their ability to measure calibrated lengths and to a certain extent form. It is recognised that, without further analysis or testing, these results...... are required. Depending on the requirements for uncertainty level, different approaches may be adopted to achieve traceability. Especially in the case of complex measurement situations and workpieces the procedures are not trivial. This paper discusses the establishment of traceability in coordinate metrology...

  7. How strongly are the magnetic anisotropy and coordination numbers ...

    Indian Academy of Sciences (India)

    Coordination number around the lanthanide ion is found to alter the magnetic behaviour of all the lanthanide complexes studied and this is contrary to the general belief that the lanthanide ions are inert and exert small ligand field interaction.High symmetric low-coordinate LnIII complexes are found to yield large Ueff values ...

  8. Relationship between Moessbauer parameters and coordination number of N atoms in GdIII coordination compounds

    International Nuclear Information System (INIS)

    Kitazawa, T.; Yanagi, K.; Kachi-Terajima, C.; Takahashi, M.

    2011-01-01

    This study took up four kinds of N-atom coordinated complexes, [Gd(H 2 L)(NO 3 ) 2 (MeOH)](NO 3 )·MeOH, [Gd(Me 3 L)(H 2 O) 2 ](NO 3 ) 3 ·3H 2 O, [Gd(H 3 L)(NO 3 )](NO 3 ) 2 ·MeOH, and mer-[Fe(CN) 3 (μ-CN)Gd(H 2 O)(o-phen) 2 ] n ·H 2 O, and measured the 155 Gd Moessbauer spectra to obtain the Moessbauer parameter of Gd III complexes. With the addition of previously reported data to these data, the authors re-examined the relationship between the Moessbauer parameter and the number of coordinated N atoms. [Gd(H 2 L)(NO 3 ) 2 (MeOH)](NO 3 )·MeOH is 10-coordination complex, coordinating five N atoms and five O atoms. [Gd(Me 3 L)(H 2 O) 2 ](NO 3 ) 3 ·3H 2 O and [Gd(H 3 L)(NO 3 )](NO 3 ) 2 ·MeOH are 9-coordination complexes, coordinating seven N atoms and two O atoms. mer-[Fe(CN) 3 (μ-CN) 3 Gd(H 2 O)(o-phen) 2 ] n ·H 2 O is 8-coordination complex coordinating seven N atoms. This study re-confirmed the previous report describing that as the coordinated number of N atoms increases, isomeric nuclei shift tends to decrease. This phenomenon suggests that the involvement in the bond of N atoms is different from O atoms. It is considered that the bond of N atoms is highly covalent than the bond of O atoms, and mainly the 6s orbit of Gd III is involved in this bond, but there is a possibility that 5d orbit and even 4f orbit are slightly involved. (A.O.)

  9. Coordination failure caused by sunspots

    DEFF Research Database (Denmark)

    Beugnot, Julie; Gürgüç, Zeynep; Øvlisen, Frederik Roose

    2012-01-01

    In a coordination game with Pareto-ranked equilibria, we study whether a sunspot can lead to either coordination on an inferior equilibrium (mis-coordination) or to out-of equilibrium behavior (dis-coordination). While much of the literature searches for mechanisms to attain coordination on the e......In a coordination game with Pareto-ranked equilibria, we study whether a sunspot can lead to either coordination on an inferior equilibrium (mis-coordination) or to out-of equilibrium behavior (dis-coordination). While much of the literature searches for mechanisms to attain coordination...

  10. Coordinate measuring machines

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with three exercises of 2 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercises concern three aspects of coordinate measuring: 1) Measuring and verification of tolerances on coordinate measuring machines, 2) Traceability...

  11. Unusual coordination modes of ligand 2-chloro-5-nitrobenzene sulfonate: Synthesis, spectroscopic characterization, thermal and X-ray structural studies of metal 2-chloro-5-nitrobenzene sulfonate complexes, metal = Tl(I), Cu(II), Ag(I) and Pb(II)

    Science.gov (United States)

    Sharma, Raj Pal; Kumar, Santosh; Venugopalan, Paloth; Aree, Thammarat; Starynowicz, Przemysław

    2016-03-01

    Using metal ions thallium(I), copper(II), silver(I) and lead(II) and ligand 2-chloro-5-nitrobenzenesulfonate(cnb), four new metal complexes [Tl(cnb)]n(1), [Cu(en)2(H2O)2](cnb)2.2H2O(2), where en = ethylenediamine, [Ag(cnb)]n(3) and [Pb(cnb)2]n(4) have been synthesized and characterized by elemental analyses, spectroscopic methods (FT-IR, multinuclear NMR), single crystal X-ray structure analyses (except 4) and TGA analyses. Complexes 1 and 3 crystallize in monoclinic crystal system in P21/c space group having unit cell dimensions, a = 13.849(2) Å, b = 9.449(2) Å, c = 7.506(2)Å, β = 105.3°, V = 947.1 Å3, Z = 4 and a = 15.197(13)Å, b = 5.136(4)Å, c = 24.058(18)Å, β = 106.86°, V = 1797.1 Å3, Z = 4 respectively. Complex 2, crystallizes in triclinic crystal system with PI bar having unit cell parameters; a = 6.888 Å, b = 7.835 Å, c = 13.227 Å, α = 80.20°, β = 83.15°, γ = 78.18°, V = 945.6 Å3, Z = 1. X-ray structure determination revealed that complexes 1 and 3 are polymeric in nature, whereas complex 2 has ionic structure. Remarkably, cnb ligand is coordinating through sulfonato oxygen atoms and nitro oxygen atoms in thallium complex but coordinates through sulfonato oxygen atoms and chloro group in silver complex, thereby showing the flexible/versatile coordinating behaviour of anionic ligand. This is unusual.

  12. Novel Viologen Derivative Based Uranyl Coordination Polymers Featuring Photochromic Behaviors.

    Science.gov (United States)

    Hu, Kong-Qiu; Wu, Qun-Yan; Mei, Lei; Zhang, Xiao-Lin; Ma, Lei; Song, Gang; Chen, Di-Yun; Wang, Yi-Tong; Chai, Zhi-Fang; Shi, Wei-Qun

    2017-12-19

    A series of novel uranyl coordination polymers have been synthesized by hydrothermal reactions. Both complexes 1 and 2 prosess two ipbp - ligands (H 2 ipbpCl=1-(3,5-dicarboxyphenyl)-4,4'-bipyridinium chloride), one uranyl cation, and two coordination water molecules, which can further extend to 2D networks through hydrogen bonding. In complex 1, two sets of equivalent nets are entangled together, resulting in a 2D + 2D → 3D polycatenated framework. In complex 2, the neighbouring equivalent nets interpenetrate each other, forming a twofold interpenetrated network. Complexes 3 and 4 are isomers, and both of them are constructed from (UO 2 ) 2 (OH) 2 dinuclear units, which are connected with four ipbp - ligands. The 3D structures of complexes 3 and 4 are similar along the b axis. Similar to other viologen-based coordination polymers, complexes 3 and 4 exhibit photochromic and thermochromic properties, which are rarely observed in actinide coordination polymers. Unlike the monotonous coordination mode in complexes 1-4, the ipbp - ligands feature a μ 3 -bridge through two kinds of coordination modes in complex 5. Notably, complex 5 presents a unique example in which terminal pyridine nitrogen atom is involved in the coordination. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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.

    Science.gov (United States)

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

    2016-09-06

    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

  14. Coordinating Interactions: The Event Coordination Notation

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    on a much more technical level. The Event Coordination Notation (ECNO) allows modelling the behaviour of an application on a high level of abstraction that is closer to the application’s domain than to the software realizing it. Still, these models contain all necessary details for actually executing...... the models and for generating code from them. In order to be able to model the behaviour of a domain, the ECNO makes the events in which the different elements of the domain could engage explicit. The local behaviour of an element defines at which time an element can engage or participate in an event....... The global behaviour of the application results from different elements jointly engaging in such events, which is called an interaction. Which events are supposed to be jointly executed and which elements need to join in is defined by so-called coordination diagrams of the ECNO. Together, the models...

  15. Hypersensitive transition spectrum of f-element and coordination structure

    International Nuclear Information System (INIS)

    Cao Xuan; Song Chongli; Zhu Youngjun

    1992-10-01

    Some f-f transitions of Ln(An) metallic ions have particular super-sensitivity to the change of coordination environments. This is called super-sensitive transitions. Based on the irreducible tensor operator method, a computation model and corresponding computer program for calculating the hypersensitive transition spectrum of f-element were developed. By comparing the theoretical spectra of all possible coordination structures with experimental one, the possible coordination structures of complex can be determined. The coordination structures of Nd 3+ , Er 3 + hydrate and their extraction complex with H(DEHP) were successfully determined by this method, and the experimental spectra were also assigned

  16. Developmental coordination disorder

    Science.gov (United States)

    Developmental coordination disorder can lead to: Learning problems Low self-esteem resulting from poor ability at sports and teasing by other children Repeated injuries Weight gain as a result of not wanting to participate ...

  17. Supercritical Airfoil Coordinates

    Data.gov (United States)

    National Aeronautics and Space Administration — Rectangular Supercritical Wing (Ricketts) - design and measured locations are provided in an Excel file RSW_airfoil_coordinates_ricketts.xls . One sheet is with Non...

  18. Regional transit coordination guidebook.

    Science.gov (United States)

    2009-01-01

    Constant growth in rural areas and extensive suburban development have contributed to increasingly more people needing seamless and adequate public transportation into and from nearby cities. Coordinating existing services or determining the need for...

  19. Environmental Compliance Issue Coordination

    Science.gov (United States)

    An order to establish the Department of Energy (DOE) requirements for coordination of significant environmental compliance issues to ensure timely development and consistent application of Departmental environmental policy and guidance

  20. Haskell_#: Coordinating Functional Processes

    OpenAIRE

    Junior, Francisco Heron de Carvalho; Lins, Rafael Dueire

    2012-01-01

    This paper presents Haskell#, a coordination language targeted at the efficient implementation of parallel scientific applications on loosely coupled parallel architectures, using the functional language Haskell. Examples of applications, their implementation details and performance figures are presented.

  1. Understanding social motor coordination.

    Science.gov (United States)

    Schmidt, R C; Fitzpatrick, Paula; Caron, Robert; Mergeche, Joanna

    2011-10-01

    Recently there has been much interest in social coordination of motor movements, or as it is referred to by some researchers, joint action. This paper reviews the cognitive perspective's common coding/mirror neuron theory of joint action, describes some of its limitations and then presents the behavioral dynamics perspective as an alternative way of understanding social motor coordination. In particular, behavioral dynamics' ability to explain the temporal coordination of interacting individuals is detailed. Two experiments are then described that demonstrate how dynamical processes of synchronization are apparent in the coordination underlying everyday joint actions such as martial art exercises, hand-clapping games, and conversations. The import of this evidence is that emergent dynamic patterns such as synchronization are the behavioral order that any neural substrate supporting joint action (e.g., mirror systems) would have to sustain. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Learning From Movie-Sets Coordination

    DEFF Research Database (Denmark)

    Egebjerg, Christin

    A comparative study of large, professional movie sets and construction sites revealed that conditions for movie production were far more complex and unpredictable, with sudden surprises, changing facilities and often hundreds of people from independent professional groups to be coordinated from h...

  3. Assembling one-dimensional coordination polymers into ...

    Indian Academy of Sciences (India)

    ... analyses of these complexes reveal that the one-dimensional networks observed here are of three types: simple linear chain, chains with wavy nature and chains containing cavities. The self-complementary amide groups of the ligands assembled these coordination networks into higher dimensional architectures via N-H ...

  4. Coordination Chemistry of Life Processes: Bioinorganic Chemistry ...

    Indian Academy of Sciences (India)

    Many enzymes and proteins have metal ions at their active sites that play key roles in catalysis. An important goal of an interdisciplinary field like bioinorganic chem- istry is the development of small inorganic coordination complexes that not only reproduce structural and spec- troscopic features, but also function in a ...

  5. Complex Covariance

    Directory of Open Access Journals (Sweden)

    Frieder Kleefeld

    2013-01-01

    Full Text Available According to some generalized correspondence principle the classical limit of a non-Hermitian quantum theory describing quantum degrees of freedom is expected to be the well known classical mechanics of classical degrees of freedom in the complex phase space, i.e., some phase space spanned by complex-valued space and momentum coordinates. As special relativity was developed by Einstein merely for real-valued space-time and four-momentum, we will try to understand how special relativity and covariance can be extended to complex-valued space-time and four-momentum. Our considerations will lead us not only to some unconventional derivation of Lorentz transformations for complex-valued velocities, but also to the non-Hermitian Klein-Gordon and Dirac equations, which are to lay the foundations of a non-Hermitian quantum theory.

  6. [Binocular coordination during reading].

    Science.gov (United States)

    Bassou, L; Granié, M; Pugh, A K; Morucci, J P

    1992-01-01

    Is there an effect on binocular coordination during reading of oculomotor imbalance (heterophoria, strabismus and inadequate convergence) and of functional lateral characteristics (eye preference and perceptually privileged visual laterality)? Recordings of the binocular eye-movements of ten-year-old children show that oculomotor imbalances occur most often among children whose left visual perceptual channel is privileged, and that these subjects can present optomotor dissociation and manifest lack of motor coordination. Close binocular motor coordination is far from being the norm in reading. The faster reader displays saccades of differing spatial amplitude and the slower reader an oculomotor hyperactivity, especially during fixations. The recording of binocular movements in reading appears to be an excellent means of diagnosing difficulties related to visual laterality and to problems associated with oculomotor imbalance.

  7. The Influence of Telepathology on Coordination Practices.

    Science.gov (United States)

    Meyer, Julien; Paré, Guy

    2018-01-03

    Coordination between physicians and allied professionals is essential to the effective delivery of care services and is associated with positive patient outcomes. As information technology can radically transform how professionals collaborate, both researchers and healthcare accreditation bodies are devoting a growing interest to the means of achieving better coordination. The primary aim of this study is to explain the extent to which and how coordination practices between pathologists, technologists, and surgeons are transformed when telepathology is being implemented. An interpretive case study was conducted. A total of 60 semistructured interviews with key participants were conducted, in addition to several days of direct observation of telepathology-based intraoperative consultations (IOCs). Three major kinds of transformation of coordination practices were observed. First, the telepathology system itself constrains and disrupts coordination routines, such as the presentation of slides. Second, anticipating IOC, proactively performed by the laboratory personnel in traditional settings, requires more formal requests in a telepathology context. Third, local technologists become more autonomous in performing complex macroscopy manipulations and managing the laboratory tasks traditionally performed by pathologists. Successful coordination of work in a telepathology-based IOC context requires that significant transformations be anticipated and accounted for. Project managers need to formalize new work processes, support the transformations in professional roles, and mitigate the major hindrances that small material changes may have on work routines.

  8. Postural Coordination during Socio-motor Improvisation.

    Science.gov (United States)

    Gueugnon, Mathieu; Salesse, Robin N; Coste, Alexandre; Zhao, Zhong; Bardy, Benoît G; Marin, Ludovic

    2016-01-01

    Human interaction often relies on socio-motor improvisation. Creating unprepared movements during social interaction is not a random process but relies on rules of synchronization. These situations do not only involve people to be coordinated, but also require the adjustment of their posture in order to maintain balance and support movements. The present study investigated posture in such a context. More precisely, we first evaluated the impact of amplitude and complexity of arm movements on posture in solo situation. Then, we assessed the impact of interpersonal coordination on posture using the mirror game in which dyads performed improvised and synchronized movements (i.e., duo situation). Posture was measured through ankle-hip coordination in medio-lateral and antero-posterior directions (ML and AP respectively). Our results revealed the spontaneous emergence of in-phase pattern in ML direction and antiphase pattern in AP direction for solo and duo situations. These two patterns respectively refer to the simultaneous flexion/extension of the ankles and the hips in the same or opposite direction. It suggests different functional roles of postural coordination patterns in each direction, with in-phase supporting task performance in ML (dynamical stability) and antiphase supporting postural control in AP (mechanical stability). Although amplitude of movement did not influence posture, movement complexity disturbed postural stability in both directions. Conversely, interpersonal coordination promoted postural stability in ML but not in AP direction. These results are discussed in terms of the difference in coupling strength between ankle-hip coordination and interpersonal coordination.

  9. Quantifying linguistic coordination

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Tylén, Kristian

    task (Bahrami et al 2010, Fusaroli et al. 2012) we extend to linguistic coordination dynamical measures of recurrence employed in the analysis of sensorimotor coordination (such as heart-rate (Konvalinka et al 2011), postural sway (Shockley 2005) and eye-movements (Dale, Richardson and Kirkham 2012......). We employ nominal recurrence analysis (Orsucci et al 2005, Dale et al 2011) on the decision-making conversations between the participants. We report strong correlations between various indexes of recurrence and collective performance. We argue this method allows us to quantify the qualities...

  10. Coordinate Standard Measurement Development

    Energy Technology Data Exchange (ETDEWEB)

    Hanshaw, R.A.

    2000-02-18

    A Shelton Precision Interferometer Base, which is used for calibration of coordinate standards, was improved through hardware replacement, software geometry error correction, and reduction of vibration effects. Substantial increases in resolution and reliability, as well as reduction in sampling time, were achieved through hardware replacement; vibration effects were reduced substantially through modification of the machine component dampening and software routines; and the majority of the machine's geometry error was corrected through software geometry error correction. Because of these modifications, the uncertainty of coordinate standards calibrated on this device has been reduced dramatically.

  11. Recursive Advice for Coordination

    DEFF Research Database (Denmark)

    Terepeta, Michal Tomasz; Nielson, Hanne Riis; Nielson, Flemming

    2012-01-01

    Aspect-oriented programming is a programming paradigm that is often praised for the ability to create modular software and separate cross-cutting concerns. Recently aspects have been also considered in the context of coordination languages, offering similar advantages. However, introducing aspect...... systems. Even though primarily used for analysis of recursive programs, we are able to adapt them to fit this new context.......Aspect-oriented programming is a programming paradigm that is often praised for the ability to create modular software and separate cross-cutting concerns. Recently aspects have been also considered in the context of coordination languages, offering similar advantages. However, introducing aspects...

  12. The psychological selection profile for civil-military coordination ...

    African Journals Online (AJOL)

    The introduction of a multidimensional approach towards peace missions in complex emergencies emphasises the importance of coordination between the military and humanitarian components at all levels of interaction. Cooperation and coordination between the military and humanitarian components are critical in ...

  13. Coordination Chemistry of SCS PdII Pincer Systems

    NARCIS (Netherlands)

    van Manen, H.J.; Nakashima, Kazuaki; Nakashima, K.; Shinkai, Seiji; Kooijman, Huub; Spek, Anthony L.; van Veggel, F.C.J.M.; Reinhoudt, David

    2000-01-01

    We have studied the coordination of substituted pyridines, and phosphorus- and sulfur-containing ligands to an SCS PdII pincer system. These ligands coordinate to PdII (trans to the cyclopalladated aryl group) by quantitative substitution of the labile acetonitrile ligand in complex 1. Competition

  14. A channel-based coordination model for component composition

    NARCIS (Netherlands)

    F. Arbab (Farhad)

    2002-01-01

    textabstractIn this paper, we present $P epsilon omega$, a paradigm for composition of software components based on the notion of mobile channels. $P repsilon omega$ is a channel-based exogenous coordination model wherein complex coordinators, called {em connectors are compositionally built out of

  15. Copper inorganic-organic hybrid coordination compound as a novel ...

    Indian Academy of Sciences (India)

    coordinates to a Cu(II) ion in a meridional fashion and defines the basal plane of the complex. The fourth equatorial coordination ... the final structures of demanded crystalline products is a great challenge. The self-assembly process of crys- talline products is influenced by various factors, such as metal salt, organic ligands, ...

  16. Recent developments in nonaqueous plutonium coordination chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gaunt, A.J. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Neu, M.P. [Associate Directorate for Chemistry, Life, and Earth Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    2010-06-15

    This account highlights recent research from our laboratory on nonaqueous plutonium coordination chemistry. The preparation of organic-soluble synthons, the reactivity of plutonium with soft donor atom ligands, and initial characterization of resultant complexes are presented. Homoleptic soft donor complexes are targeted, to contrast with the much larger body of actinide chemistry that focuses covalency and reactivity within one to three sites in the coordination sphere. Structural parameters from X-ray structure determination and computation indicate small, yet significant, differences in covalency between isostructural plutonium and lanthanide complexes. Results are discussed in the context of our aim to expand the fundamental chemistry of plutonium, particularly to address challenges in the nuclear industry. (authors)

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

    Science.gov (United States)

    El-Boraey, Hanaa A.

    2012-11-01

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

  18. Coordination failure caused by sunspots

    DEFF Research Database (Denmark)

    Beugnot, Julie; Gürgüç, Zeynep; Øvlisen, Frederik Roose

    2012-01-01

    on the efficient equilibrium, we consider sunspots as a potential reason for coordination failure. We conduct an experiment with a three player 2x2x2 game in which coordination on the efficient equilibrium is easy and should normally occur. In the control session, we find almost perfect coordination on the payoff......-dominant equilibrium, but in the sunspot treatment, dis-coordination is frequent. Sunspots lead to significant inefficiency, and we conclude that sunspots can indeed cause coordination failure....

  19. Coordination Compounds in Biology

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 6. Coordination Compounds in Biology - The Chemistry of Vitamin B12 and Model Compounds. K Hussian Reddy. General Article Volume 4 Issue 6 June 1999 pp 67-77 ...

  20. Coordination Compounds in Biology

    Indian Academy of Sciences (India)

    Coordination Compounds in Biology equatorial ligand, there are two axial ligands in most B. 12 derivatives. Derivatives of B12. The various derivatives of B. 12 result most commonly from changes in the axial ligands bound to cobalt. Often it is convenient to draw a greatly abbreviated structure for a B. 12 molecule using a ...

  1. Coordination of mobile labor

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    2008-01-01

    Roč. 139, č. 1 (2008), s. 25-46 ISSN 0022-0531 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : coordination * general equilibrium * global games Subject RIV: AH - Economics Impact factor: 1.224, year: 2008

  2. Block coordination copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Kyoung Moo; Wong-Foy, Antek G.; Matzger, Adam J.; Benin, Annabelle I.; Willis, Richard R.

    2012-12-04

    The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

  3. Block coordination copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Kyoung Moo; Wong-Foy, Antek G; Matzger, Adam J; Benin, Annabelle I; Willis, Richard R

    2014-11-11

    The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

  4. Block coordination copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Kyoung Moo; Wong-Foy, Antek G; Matzger, Adam J; Benin, Annabelle I; Willis, Richard R

    2012-11-13

    The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

  5. Reusability of coordination programs

    NARCIS (Netherlands)

    F. Arbab (Farhad); C.L. Blom (Kees); F.J. Burger (Freek); C.T.H. Everaars (Kees)

    1996-01-01

    textabstractIsolating computation and communication concerns into separate pure computation and pure coordination modules enhances modularity, understandability, and reusability of parallel and/or distributed software. This can be achieved by moving communication primitives (such as SendMessage and

  6. Intelligent navigation and multivehicle coordination

    Science.gov (United States)

    McKay, Mark D.; Anderson, Matthew O.; Kinoshita, Robert A.; Flann, Nicholas S.

    1999-07-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) and Utah State University's Center for Self-Organizing and Intelligent Systems have developed a team of autonomous robotic vehicles. This paper discusses the development of a strategy that uses a sophisticated, highly intelligent sensor platform to allow centralized coordination between smaller and inexpensive robots. The three components of the multi-agent cooperative scheme are small-scale robots, large-scale robots, and the central control station running a mission and path- planning software. The smaller robots are used for activities where the probability of loss increases, such as Unexploded Ordnance (UXO) or mine detonation. The research is aimed at building simple, inexpensive multi-agent vehicles and an intelligent navigation and multi-vehicle coordination system suitable for UXO, environmental remediation or mine detection. These simplified robots are capable of conducting hunting missions using low-cost positioning sensors and intelligent algorithms. Additionally, a larger sensor-rich intelligent system capable of transporting smaller units to outlying remote sites has been developed. The larger system interfaces to the central control station and provides navigation assistance to multiple low-cost vehicles. Finally, mission and path-planning software serves as the operator control unit, allowing central data collection, map creation and tracking, and an interface to the larger system as well as each smaller unit. The power of this scheme is the ability to scale to the appropriate level for the complexity of the mission.

  7. DNA- and BSA-binding studies and anticancer activity against human breast cancer cells (MCF-7) of the zinc(II) complex coordinated by 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine.

    Science.gov (United States)

    Anjomshoa, Marzieh; Fatemi, Seyed Jamilaldin; Torkzadeh-Mahani, Masoud; Hadadzadeh, Hassan

    2014-06-05

    Binding studies of a mononuclear zinc(II) complex, [Zn(dppt)2Cl2] (dppt is 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine), with DNA and bovine serum albumin (BSA) have been investigated under physiological conditions. The binding properties of the complex with fish sperm DNA (FS-DNA) have been investigated by UV-Vis absorption, thermal denaturation, competitive DNA-binding studies with ethidium bromide (EB) by fluorescence, and gel electrophoresis techniques. The competitive study with (EB) shows that the complex can displace EB from the DNA-EB system and compete for the DNA-binding sites with EB, which is usually characteristic of the intercalative interaction of compounds with DNA. The value of the fluorescence quenching constant (Ksv) was obtained as 3.1×10(4)M(-1), indicating that this complex shows a high quenching efficiency and a significant degree of binding to DNA. Moreover, the intercalative binding mode has also been verified by the results of UV-Vis absorption, thermal denaturation and gel electrophoresis. The value of Kb at room temperature was calculated to be 1.97×10(5)M(-1), indicating that the complex possesses strong tendency to bind with DNA. This value is very greater than to the values obtained for other zinc(II) complexes. The interaction of the complex with BSA has been studied by UV-Vis absorption, fluorescence and circular dichroism (CD) spectroscopic techniques. The results indicate that the complex has a quite strong ability to quench the fluorescence of BSA and the binding reaction is mainly a static quenching process. The quenching constants (KSV), the binding constants (Kb), the number of binding sites at different temperatures, the binding distance between BSA and the complex (r), and the thermodynamic parameters (ΔH(o), ΔS(o) and ΔG(o)) between BSA and the complex were calculated. The complex exhibits good binding propensity to BSA showing relatively high binding constant values. The positive ΔH(o) and ΔS(o) values indicate that

  8. Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II).

    Science.gov (United States)

    Haslinger, Stefan; Pöthig, Alexander; Cokoja, Mirza; Kühn, Fritz E

    2015-12-01

    Iron is of interest as a catalyst because of its established use in the Haber-Bosch process and because of its high abundance and low toxicity. Nitrogen-heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron-NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1'-bis(pyridin-2-yl)-2,2-bi(1H-imidazole)-κN(3)][3,3'-bis(pyridin-2-yl-κN)-1,1'-methanediylbi(1H-imidazol-2-yl-κC(2))](trimethylphosphane-κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C-C-coupled biimidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.

  9. Some high coordination compounds of lanthanides(III) derived from ...

    African Journals Online (AJOL)

    isonicotinamidosalicyaldimine. Ram K. Agarwal, Himanshu Agarwal. Abstract. A new series of lanthanide(III) nitrates, isothiocyanates and perchlorates coordination complexes of N-isonicotinamidosalicyaldimine (INH-SAL) with the general composition ...

  10. From business value model to coordination process model

    NARCIS (Netherlands)

    Fatemi, Hassan; Wieringa, Roelf J.; Poler, R.; van Sinderen, Marten J.; Sanchis, R.

    2009-01-01

    The increased complexity of business webs calls for modeling the collaboration of enterprises from different perspectives, in particular the business and process perspectives, and for mutually aligning these perspectives. Business value modeling and coordination process modeling both are necessary

  11. 2,3-Bis(1-methylimidazol-2-yl)quinoxaline (bmiq), a new ligand with decoupled electron transfer and metal coordination sites: the very different redox behaviour of isoelectronic complexes with [PtCl2] and [AuCl2](+)

    Czech Academy of Sciences Publication Activity Database

    Bulak, E.; Varnali, T.; Schwederski, B.; Sarkar, B.; Hartenbach, I.; Fiedler, Jan; Kaim, W.

    2011-01-01

    Roč. 40, č. 12 (2011), s. 2757-2763 ISSN 1477-9226 R&D Projects: GA MŠk LD11086; GA MŠk(CZ) LD11082 Institutional research plan: CEZ:AV0Z40400503 Keywords : plainum(II) diimine complexes * polypyridyl ligands * dinuclear complexes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.838, year: 2011

  12. Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kaminsky, W.

    Synthesis of (η6-arene) ruthenium (II) complexes has attracted considerable attention owing to their anti-cancer [1-3], antiviral [4] and catalytic properties [5-7]. The catalytic activities of these complexes range from hydrogen transfer to ring closing...

  13. Self-assembly of mixed-valence Co(II/III) and Ni(II) clusters: azide-bridged 1D single chain coordination polymers comprised of tetranuclear units, tetranuclear Co(II/III) complexes, ferromagnetically coupled azide-bridged tetranuclear, and hexanuclear Ni(II) complexes: synthesis, structural, and magnetic properties.

    Science.gov (United States)

    Tandon, Santokh S; Bunge, Scott D; Rakosi, Robert; Xu, Zhiqiang; Thompson, Laurence K

    2009-09-07

    One-pot reactions between 2,6-diformyl-4-methylphenol (DFMP) and 2-aminoethanol (AE) in the presence of cobalt(II) salts [Co(ClO4)2, CoCl2, Co(CH3CO2)2, Co(NO3)2] and sodium azide result in the self-assembly of novel one-dimensional single chain mixed-valence cobalt coordination polymers {[Co2(II)Co2(III) (HL)2(OCH3)2(N3)3]ClO(4).5H2O.CH3OH}n (1), {[Co2(II)Co2(III) (HL)2(OCH3)2(N3)3]Cl.H2O}n (2) in which tetra-cobalt cationic units are bridged by symmetrical 1,3-azides, forming single chains; mixed valence neutral tetranuclear clusters [Co2(II)Co2(III) (HL)2(OCH3)2(N3)4]CH3OH.2H2O (3), [Co2(II)Co2(III)(HL)2(OCH3)2(N3)2(CH3CO2)2].2CH3OH.2H2O (4), and the cationic cluster [Co2(II) Co2(III) (HL)2(OCH3)2(CH3OH)2(N3)2](NO3)2 (5). In all these reactions, H3L, the potentially pentadentate (N2O3), trianionic double Schiff base ligand 2,6-bis[(2-hydroxy-ethylimino)-methyl]-4-methylphenol is formed. The reaction between DFMP and AE in the presence of nickel(ii) salts and sodium azide in methanol-water mixture results in the self-assembly of ferromagnetically coupled hexanuclear complexes [Ni6(H2L)2(HL-1)2(H2O)2(N3)6](ClO4)(2).2CH3OH (6), and [Ni6(H2L)2(HL-1)2(CH3OH)2(N3)6](BF4)2 (7), involving double (H3L) and single (H2L-1) Schiff base ligands, and a neutral tetranuclear complex [Ni4(H2L)2(OCH3)2(CH3CO2)2(N3)2] (8) with only double Schiff-base (H3L). In these complexes, the nature of the anion and the reaction conditions seem to play an important role in directing the formation of tetranuclear, hexanuclear or polymeric clusters. All complexes involve divacant double cubane-type cores containing three to four different types of bridging ligands (phenoxy, azido, methoxy/alkoxy, and acetate). Variable temperature magnetic properties of these spin coupled clusters have been investigated and magneto-structural correlations have been established.

  14. Coordination: Neural, Behavioral and Social Dynamics

    CERN Document Server

    Fuchs, Armin

    2008-01-01

    One of the most striking features of Coordination Dynamics is its interdisciplinary character. The problems we are trying to solve in this field range from behavioral phenomena of interlimb coordination and coordination between stimuli and movements (perception-action tasks) through neural activation patterns that can be observed during these tasks to clinical applications and social behavior. It is not surprising that close collaboration among scientists from different fields as psychology, kinesiology, neurology and even physics are imperative to deal with the enormous difficulties we are facing when we try to understand a system as complex as the human brain. The chapters in this volume are not simply write-ups of the lectures given by the experts at the meeting but are written in a way that they give sufficient introductory information to be comprehensible and useful for all interested scientists and students.

  15. Photochemically Induced Isomerisation of Ruthenium Polypyridyl Complexes

    NARCIS (Netherlands)

    Fanni, Stefano; Weldon, Frances M.; Hammarström, Leif; Mukhtar, Emad; Browne, Wesley R.; Keyes, Tia E.; Vos, Johannes G.

    2001-01-01

    The synthesis and characterisation of a series of ruthenium polypyridyl complexes containing pyridyltriazole ligands in different coordination modes are described. The electrochemical and electronic properties of the compounds with respect to the coordination mode of the pyridyltriazole ligand are

  16. Testing the nature of reaction coordinate describing interaction of H2 with carbonyl carbon, activated by Lewis acid complexation, and the Lewis basic solvent: A Born-Oppenheimer molecular dynamics study with explicit solvent

    Science.gov (United States)

    Heshmat, Mojgan; Privalov, Timofei

    2017-09-01

    Using Born-Oppenheimer molecular dynamics (BOMD), we explore the nature of interactions between H2 and the activated carbonyl carbon, C(carbonyl), of the acetone-B(C6F5)3 adduct surrounded by an explicit solvent (1,4-dioxane). BOMD simulations at finite (non-zero) temperature with an explicit solvent produced long-lasting instances of significant vibrational perturbation of the H—H bond and H2-polarization at C(carbonyl). As far as the characteristics of H2 are concerned, the dynamical transient state approximates the transition-state of the heterolytic H2-cleavage. The culprit is the concerted interactions of H2 with C(carbonyl) and a number of Lewis basic solvent molecules—i.e., the concerted C(carbonyl)⋯H2⋯solvent interactions. On one hand, the results presented herein complement the mechanistic insight gained from our recent transition-state calculations, reported separately from this article. But on the other hand, we now indicate that an idea of the sufficiency of just one simple reaction coordinate in solution-phase reactions can be too simplistic and misleading. This article goes in the footsteps of the rapidly strengthening approach of investigating molecular interactions in large molecular systems via "computational experimentation" employing, primarily, ab initio molecular dynamics describing reactants-interaction without constraints of the preordained reaction coordinate and/or foreknowledge of the sampling order parameters.

  17. Synthesis of a ruthenium(II) bipyridyl complex coordinated by a functionalized Schiff base ligand: characterization, spectroscopic and isothermal titration calorimetry measurements of M2+ binding and sensing (M2+=Ca2+, Mg2+).

    Science.gov (United States)

    Dixit, Namrata; Mishra, Lallan; Mustafi, Sourajit M; Chary, Kandala V R; Houjou, Hirohiko

    2009-07-01

    Bis-[methylsalicylidine-4'benzoic acid]-ethylene (LH2) complexed with cis-Ru(bpy)2Cl(2).2H2O provides a complex of composition [Ru(bpy)2L].2NH4PF6 (1), which has been characterized spectroscopically. Its binding behaviour towards Mg2+ and Ca2+ ions is monitored using 1H NMR titration, isothermal titration calorimetry (ITC) and luminescence microscopy. The luminescent ruthenium complex binds Ca2+ in a more selective manner as compared to Mg2+.

  18. Axially chiral allenyl gold complexes.

    Science.gov (United States)

    Johnson, Alice; Laguna, Antonio; Gimeno, M Concepción

    2014-09-17

    Unprecedented allenyl gold complexes have been achieved starting from triphenylpropargylphosphonium bromide. Two different coordination modes of the allene isomer of triphenylphosphoniumpropargylide to gold have been found depending on the gold oxidation state. Bromo-, pentafluorophenyl-, and triphenylphosphine-gold(I) allenyl complexes were prepared in which the α carbon coordinates to the gold(I) center. A chiral pentafluorophenyl-gold(III) allenyl complex with the gold atoms coordinated to the γ carbon was also prepared. All the complexes have been structurally characterized by X-ray diffraction showing the characteristic distances for a C═C═C unit.

  19. Improving Project Manufacturing Coordination

    Directory of Open Access Journals (Sweden)

    Korpivaara Ville

    2014-09-01

    Full Text Available The objective of this research is to develop firms’ project manufacturing coordination. The development will be made by centralizing the manufacturing information flows in one system. To be able to centralize information, a deep user need assessment is required. After user needs have been identified, the existing system will be developed to match these needs. The theoretical background is achieved through exploring the literature of project manufacturing, development project success factors and different frameworks and tools for development project execution. The focus of this research is rather in customer need assessment than in system’s technical expertise. To ensure the deep understanding of customer needs this study is executed by action research method. As a result of this research the information system for project manufacturing coordination was developed to respond revealed needs of the stakeholders. The new system improves the quality of the manufacturing information, eliminates waste in manufacturing coordination processes and offers a better visibility to the project manufacturing. Hence it provides a solid base for the further development of project manufacturing.

  20. Universal mechatronics coordinator

    Science.gov (United States)

    Muir, Patrick F.

    1999-11-01

    Mechatronic systems incorporate multiple actuators and sensor which must be properly coordinated to achieve the desired system functionality. Many mechatronic systems are designed as one-of-a-kind custom projects without consideration for facilitating future system or alterations and extensions to the current syste. Thus, subsequent changes to the system are slow, different, and costly. It has become apparent that manufacturing processes, and thus the mechatronics which embody them, need to be agile in order to more quickly and easily respond to changing customer demands or market pressures. To achieve agility, both the hardware and software of the system need to be designed such that the creation of new system and the alteration and extension of current system is fast and easy. This paper describes the design of a Universal Mechatronics Coordinator (UMC) which facilitates agile setup and changeover of coordination software for mechatronic systems. The UMC is capable of sequencing continuous and discrete actions that are programmed as stimulus-response pairs, as state machines, or a combination of the two. It facilitates the modular, reusable programing of continuous actions such as servo control algorithms, data collection code, and safety checking routines; and discrete actions such as reporting achieved states, and turning on/off binary devices. The UMC has been applied to the control of a z- theta assembly robot for the Minifactory project and is applicable to a spectrum of widely differing mechatronic systems.

  1. Coordinating Shared Activities

    Science.gov (United States)

    Clement, Bradley

    2004-01-01

    Shared Activity Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common resources as floor space, raw materials, and transports. ShAC iteratively invokes the Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program to replan and propagate changes to other planning programs in an effort to resolve conflicts. A domain-expert specifies which activities and parameters thereof are shared and reports the expected conditions and effects of these activities on the environment. By specifying these conditions and effects differently for each planning program, the domain-expert subprogram defines roles that each spacecraft plays in a coordinated activity. The domain-expert subprogram also specifies which planning program has scheduling control over each shared activity. ShAC enables sharing of information, consensus over the scheduling of collaborative activities, and distributed conflict resolution. As the other planning programs incorporate new goals and alter their schedules in the changing environment, ShAC continually coordinates to respond to unexpected events.

  2. Global coordination: weighted voting

    Directory of Open Access Journals (Sweden)

    Jan-Erik Lane

    2014-03-01

    Full Text Available In order to halt the depletion of global ecological capital, a number of different kinds of meetings between Governments of countries in the world has been scheduled. The need for global coordination of environmental policies has become ever more obvious, supported by more and more evidence of the running down of ecological capital. But there are no formal or binding arrangements in sight, as global environmental coordination suffers from high transaction costs (qualitative voting. The CO2 equivalent emissions, resulting in global warming, are driven by the unstoppable economic expansion in the global market economy, employing mainly fossil fuel generated energy, although at the same time lifting sharply the GDP per capita of several emerging countries. Only global environmental coordination on the successful model of the World Band and the IMF (quantitative voting can stem the rising emissions numbers and stop further environmental degradation. However, the system of weighted voting in the WB and the IMF must be reformed by reducing the excessive voting power disparities, for instance by reducing all member country votes by the cube root expression.

  3. DFT study and crystal structure analysis of a new nano-structure five coordinated Hg(II) complex involving C-H⋯O, N⋯O and π⋯π interactions in a supra-molecular structure.

    Science.gov (United States)

    Montazerozohori, M; Musavi, S A; Masoudiasl, A; Hojjati, A; Assoud, A

    2015-08-05

    In this research, template synthesis and crystal structure of a new HgLI₂ complex are presented (L=N(1)-(4-nitrobenzylidene)-N(2)-(2-((E)-(4-nitrobenzylidene)amino)ethyl)ethane-1,2-diamine). The mercury complex crystallizes in the triclinic system with space group of P1¯. The crystal structure of the complex shows a distorted trigonal bipyramidal geometry around the mercury(II) center; including two I and an N atoms of Schiff base ligand in equatorial plane and two iminic N atoms in axial positions. Two five membered mercury containing rings [Hg(-N-C-C-N-)] are found in the structure. Some C-H⋯O, N⋯O and π⋯π intermolecular interactions causes a supra-molecular network in the solid-state. In addition to crystal structure analysis, density functional theory (DFT) study at the B3LYP/LanL2DZ level of theory has been also performed on the structure. Thereafter some theoretical structural and spectral data were compared with experimental results. Furthermore, total energy levels of HOMO and LUMO orbitals, molecular electrostatic potential, Mullikan atomic charges, thermodynamic and polarizability properties of the complex were calculated. Finally the mercury complex was prepared in nano-structure size confirmed by SEM and XRD analyses. The particles size of the titled complex was evaluated under 40 nm based on Sherrer's formula. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Communicating Processes with Data for Supervisory Coordination

    Directory of Open Access Journals (Sweden)

    Jasen Markovski

    2012-08-01

    Full Text Available We employ supervisory controllers to safely coordinate high-level discrete(-event behavior of distributed components of complex systems. Supervisory controllers observe discrete-event system behavior, make a decision on allowed activities, and communicate the control signals to the involved parties. Models of the supervisory controllers can be automatically synthesized based on formal models of the system components and a formalization of the safe coordination (control requirements. Based on the obtained models, code generation can be used to implement the supervisory controllers in software, on a PLC, or an embedded (microprocessor. In this article, we develop a process theory with data that supports a model-based systems engineering framework for supervisory coordination. We employ communication to distinguish between the different flows of information, i.e., observation and supervision, whereas we employ data to specify the coordination requirements more compactly, and to increase the expressivity of the framework. To illustrate the framework, we remodel an industrial case study involving coordination of maintenance procedures of a printing process of a high-tech Oce printer.

  5. Facilitating Group Decision-Making: Facilitator's Subjective Theories on Group Coordination

    Directory of Open Access Journals (Sweden)

    Michaela Kolbe

    2008-10-01

    Full Text Available A key feature of group facilitation is motivating and coordinating people to perform their joint work. This paper focuses on group coordination which is a prerequisite to group effectiveness, especially in complex tasks. Decision-making in groups is a complex task that consequently needs to be coordinated by explicit rather than implicit coordination mechanisms. Based on the embedded definition that explicit coordination does not just happen but is purposely executed by individuals, we argue that individual coordination intentions and mechanisms should be taken into account. Thus far, the subjective perspective of coordination has been neglected in coordination theory, which is understandable given the difficulties in defining and measuring subjective aspects of group facilitation. We therefore conducted focused interviews with eight experts who either worked as senior managers or as experienced group facilitators and analysed their approaches to group coordination using methods of content analysis. Results show that these experts possess sophisticated mental representations of their coordination behaviour. These subjective coordination theories can be organised in terms of coordination schemes in which coordination-releasing situations are facilitated by special coordination mechanisms that, in turn, lead to the perception of specific consequences. We discuss the importance of these subjective coordination theories for effectively facilitating group decision-making and minimising process losses. URN: urn:nbn:de:0114-fqs0901287

  6. Oxoperoxomolybdenum(VI complexes of catalytic and biomedical relevance: Synthesis, characterization, antibacterial activity and 3D-molecular modeling of some oxoperoxomolybdenum(VI chelates in mixed (O,O coordination environment involving maltol and β-diketoenolates

    Directory of Open Access Journals (Sweden)

    R.C. Maurya

    2016-09-01

    Full Text Available A new series of four mixed-ligand complexes of oxoperoxomolybdenum(VI of the general composition [MoO(O2(ma(L]·H2O, where maH = 3-hydroxy-2-methyl-4-pyrone and LH = o-acetoacetanisidide (o-aansH, o-acetoacetotoluidide (o-aatdH, acetylacetone (acacH or methylactoacetate (macacH, has been synthesized by the interaction of [MoO(O2]2+ (obtained in situ during the interaction of MoO3 and 30% H2O2 on continuous stirring at 50 °C for 24 h and the said ligands in aqueous-ethanol medium. The complexes so obtained have been characterized by elemental analyses, molybdenum determination, molar conductance, decomposition temperature and magnetic measurements, thermogravimetric studies, 1H NMR, IR, mass and electronic spectral studies. Antibacterial studies of one of the ligands maltol and the two representative metal complexes were also carried out and it has been observed that the complexes are more potent bactericides than the ligand. The 3D-molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compound (1 to substantiate the proposed structure. Pseudopentagonal bipyramidal structures have been proposed for these complexes.

  7. Non covalent assembly of coordination superstructures

    CERN Document Server

    Khlobystov, A N

    2002-01-01

    The main topic of this work is the design of discrete and polymeric multi-component coordination structures using non-covalent interactions between organic and inorganic molecular components. All of the structures described herein are based on transition metal cations and N-donor heterocyclic bis-exodentate ligands with different geometries and various spacer functionalities. The predominant method used for the structural characterisation of the complexes was single crystal X-ray crystallography. X-ray powder diffraction, IR and NMR spectroscopies and TEM and AFM imaging were used to characterise the bulk products from the reactions. Chapter 1 is a comparative review of non-covalent interactions relevant to coordination superstructures and covers the latest developments in the area of crystal engineering and supramolecular chemistry. The nature, geometry and relative energy of the non-covalent interactions are considered in detail in order to reveal their influence on the structure and properties of complexes...

  8. Symmetric two-coordinate photodiode

    Directory of Open Access Journals (Sweden)

    Dobrovolskiy Yu. G.

    2008-12-01

    Full Text Available The two-coordinate photodiode is developed and explored on the longitudinal photoeffect, which allows to get the coordinate descriptions symmetric on the steepness and longitudinal resistance great exactness. It was shown, that the best type of the coordinate description is observed in the case of scanning by the optical probe on the central part of the photosensitive element. The ways of improvement of steepness and linear of its coordinate description were analyzed.

  9. Work Coordination Engine

    Science.gov (United States)

    Zendejas, Silvino; Bui, Tung; Bui, Bach; Malhotra, Shantanu; Chen, Fannie; Kim, Rachel; Allen, Christopher; Luong, Ivy; Chang, George; Sadaqathulla, Syed

    2009-01-01

    The Work Coordination Engine (WCE) is a Java application integrated into the Service Management Database (SMDB), which coordinates the dispatching and monitoring of a work order system. WCE de-queues work orders from SMDB and orchestrates the dispatching of work to a registered set of software worker applications distributed over a set of local, or remote, heterogeneous computing systems. WCE monitors the execution of work orders once dispatched, and accepts the results of the work order by storing to the SMDB persistent store. The software leverages the use of a relational database, Java Messaging System (JMS), and Web Services using Simple Object Access Protocol (SOAP) technologies to implement an efficient work-order dispatching mechanism capable of coordinating the work of multiple computer servers on various platforms working concurrently on different, or similar, types of data or algorithmic processing. Existing (legacy) applications can be wrapped with a proxy object so that no changes to the application are needed to make them available for integration into the work order system as "workers." WCE automatically reschedules work orders that fail to be executed by one server to a different server if available. From initiation to completion, the system manages the execution state of work orders and workers via a well-defined set of events, states, and actions. It allows for configurable work-order execution timeouts by work-order type. This innovation eliminates a current processing bottleneck by providing a highly scalable, distributed work-order system used to quickly generate products needed by the Deep Space Network (DSN) to support space flight operations. WCE is driven by asynchronous messages delivered via JMS indicating the availability of new work or workers. It runs completely unattended in support of the lights-out operations concept in the DSN.

  10. Hydroxide ion versus chloride and methoxide as an exogenous ligand reveals the influence of hydrogen bonding with second-sphere coordination water molecules in the electron transfer kinetics of Mn complexes.

    Science.gov (United States)

    El Ghachtouli, Sanae; Guillot, Régis; Aukauloo, Ally; Dorlet, Pierre; Anxolabéhère-Mallart, Elodie; Costentin, Cyrille

    2012-03-19

    We recently reported on the synthesis of a new pentadentate N(4)O ligand, tBuL(-), together with the X-ray diffraction structure of the corresponding mononuclear manganese(III)-hydroxo complex namely [(tBuL)Mn(III)OH](ClO(4)), (1 (ClO(4))). [El Ghachtouli et al. Energy Environ. Sci. 2011, 4, 2041.] In the present work, we evidence through electrochemical analysis that complex 1(+), in the presence of water, shows a peculiar behavior toward electron-transfer kinetics. The synthesis, single-crystal X-ray diffraction, and EPR spectroscopic characterization of two other mononuclear manganese(III)-chlorido and methoxo complexes-namely, [(tBuL)Mn(III)Cl](PF(6)), (2(PF(6))) and [(tBuL)Mn(III)OMe](ClO(4)), (3(ClO(4)))-are also reported. 2(PF(6)) and 3(ClO(4)) compounds will serve as reference complexes for the electron-transfer kinetics investigation. The peculiar behavior of 1(ClO(4)) is attributed to the specificity of hydroxide anion as ligand presumably allowing intermolecular hydrogen-bonding interactions and thus affecting electron-transfer properties. © 2012 American Chemical Society

  11. Alkene insertion reactions of nitrogen-coordinated acylpalladium(II) complexes : the X-ray structure of the dicyclopentadiene insertion product [Pd(C20H23COMe)(bpy)]SO3CF3

    NARCIS (Netherlands)

    Koten, G. van; Markies, B.A.; Rietveld, M.H.P.; Boersma, J.; Spek, A.L.

    1992-01-01

    The new acylpalladium(II) complex [PdI(COMe)(bpy)] (2b, bpy = 2, 2'-bipyridyl) has been obtained by two routes; (i) by insertion of carbon monoxide into the Pd@?C bond of [PdIMe(bpy)] (1b), and (ii) by ligand exchange from [PdI(COMe)(tmeda)] (2a, tmeda = N,N,N',N'-tetramethylethanediamine). The

  12. The coordination dynamics of social neuromarkers

    Science.gov (United States)

    Tognoli, Emmanuelle; Kelso, J. A. Scott

    2015-01-01

    Social behavior is a complex integrative function that entails many aspects of the brain’s sensory, cognitive, emotional and movement capacities. Its neural processes are seldom simultaneous but occur according to precise spatiotemporal choreographies, manifested by the coordination of their oscillations within and between brains. Methods with good temporal resolution can help to identify so-called “neuromarkers” of social function and aid in disentangling the dynamical architecture of social brains. In our ongoing research, we have used dual-electroencephalography (EEG) to study neuromarker dynamics during synchronic interactions in which pairs of subjects coordinate behavior spontaneously and intentionally (social coordination) and during diachronic transactions that require subjects to perceive or behave in turn (action observation, delayed imitation). In this paper, after outlining our dynamical approach to the neurophysiological basis of social behavior, we examine commonalities and differences in the neuromarkers that are recruited for both kinds of tasks. We find the neuromarker landscape to be task-specific: synchronic paradigms of social coordination reveal medial mu, alpha and the phi complex as contributing neuromarkers. Diachronic tasks recruit alpha as well, in addition to lateral mu rhythms and the newly discovered nu and kappa rhythms whose functional significance is still unclear. Social coordination, observation, and delayed imitation share commonality of context: in each of our experiments, subjects exchanged information through visual perception and moved in similar ways. Nonetheless, there was little overlap between their neuromarkers, a result that hints strongly of task-specific neural mechanisms for social behavior. The only neuromarker that transcended both synchronic and diachronic social behaviors was the ubiquitous alpha rhythm, which appears to be a key signature of visually-mediated social behaviors. The present paper is both an

  13. A 3d-4f complex constructed by the assembly of a cationic template, [Cu(en){sub 2}]{sup 2+}, and a 3D anionic coordination polymer, [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-}

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Szu-Yu; Yeh, Chang-Tsung; Wang, Chih-Chieh [Department of Chemistry, Soochow University, Taipei, Taiwan (China); Lee, Gene-Hsiang [Instrumentation Center, National Taiwan University, Taipei, Taiwan (China); Sheu, Hwo-Shuenn [National Synchrotron Radiation Research Center, Hsinchu, Taiwan (China)

    2017-05-18

    A three-dimensional (3D) 3d-4f complex, [Cu(en){sub 2}][Sm{sub 2}(C{sub 5}O{sub 5})(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 2}].8H{sub 2}O (1) (en = ethylenediamine, C{sub 5}O{sub 5}{sup 2-} = dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione), were prepared via the in-situ ring-opening oxidation reaction of croconate in the presence of the template-directed complex, [Cu(en){sub 2}]{sup 2+} cation. The structural characterization determined by X-ray diffraction determination reveals that the 3D anionic coordination polymer of [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-} in 1 can be describe in terms of in-plane 2D honeycomb-like [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}] layered frameworks bridged by oxalate with bis-chelating mode, being mutually interlinked via the bridge of μ{sub 1,2,3,4}-croconate ligands with bis-chelating coordination mode to complete the 3D open framework, which gives rise to 1D channels with pore size of 14.023 x 11.893 Aa (longest atom-atom contact distances) along the b axis. The structure-directing complex, [Cu(en){sub 2}]{sup 2+}, and solvated water molecules are resided into these honeycomb-type hexagonal channels. The thermal stability of 1 was further studied by TGA and in-situ powder X-ray diffraction measurement. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Synthesis, chemistry and catalytic activity of complexes of lanthanide and actinide metals in unusual oxidation states and coordination environments. Progress report for period February 1, 1980-January 31, 1981

    International Nuclear Information System (INIS)

    Evans, W.J.

    1980-10-01

    Investigations are being conducted on two classes of lanthanide compounds: metal vapor co-condensation reactions with unsaturated hydrocarbons and homoleptic and heteroleptic alkyl lanthanide complexes. Three models have been considered for the interaction of erbium atoms with 3-hexyne. The structure of the heteroleptic alkynide [(C 5 H 5 ) 2 ErC triple bond CCMe 3 ] 2 was studied. Some new organolanthanides have been prepared

  15. Redox reactivity and coordination chemistry of uranium

    International Nuclear Information System (INIS)

    Nocton, G.

    2009-09-01

    The study and the understanding of actinides chemistry have important implications in the nuclear field both for the development of new actinides materials and the retreatment of the nuclear wastes. One of the major issues in that chemistry is that the actinides elements are known to undergo redox reaction and to form assemblies of different size and different topologies. In that context uranium can be a good model of the heavier radioelement because it is much less radioactive. So, this work concerns the synthesis and the study of the spectroscopy and the magnetic properties of several uranium based polymetallic assemblies synthesized by taking advantage of the redox properties and the coordination chemistry of uranium. The hydrolysis reactivity of trivalent uranium has been studied in absence of sterically hindered ligands and led to the synthesis of oxo/hydroxo uranium assemblies with different sizes by changing the starting complex or the reaction conditions. By following the same strategy, the controlled oxidation of trivalent uranium complexes led to an original azido/nitrido uranium complex. The coordination chemistry of the pentavalent uranyl polymer {[UO 2 py 5 ][KI 2 py 3 ]} n has also been studied with different ligand and in different conditions and led to several cation-cation complexes for which the stability is sufficient for studying there dismutation by proton NMR. By changing the ancillary ligands stable monomeric complexes of pentavalent uranyl complexes were also obtained. The magnetic properties of all the complexes, monomers and polymetallic complexes were studied and an antiferromagnetic coupling was observed for the cation-cation pentavalent uranyl dimer [UO 2 (dbm) 2 (K 18 C 6 )] 2 . (author)

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

    African Journals Online (AJOL)

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

  17. COORDINATION OF CASSAVA STARCH TO METAL IONS AND ...

    African Journals Online (AJOL)

    a

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

  18. Axial phenoxide coordination on di-iron(III) bisporphyrin: Insights ...

    Indian Academy of Sciences (India)

    in solid (see Experimental section, vide supra). The rep- resentative spectra are shown in figure 9 along with the high-spin complex 1. These results are also suggestive of high spin Fe(III) (S = 5/2) nature of the complex 2 both in solid and solution. 4. Conclusion. Synthesis, structures and properties of new five- coordinate ...

  19. Coordination of knowledge in judging animated motion

    Directory of Open Access Journals (Sweden)

    Thomas C. Thaden-Koch

    2006-11-01

    Full Text Available Coordination class theory is used to explain college students’ judgments about animated depictions of moving objects. diSessa’s coordination class theory models a “concept” as a complex knowledge system that can reliably determine a particular type of information in widely varying situations. In the experiment described here, fifty individually interviewed college students judged the realism of two sets of computer animations depicting balls rolling on a pair of tracks. The judgments of students from an introductory physics class were strongly affected by the number of balls depicted (one or two, but the judgments of students from an educational psychology class were not. Coordination analysis of interview transcripts supports the interpretation that physics students’ developing physics knowledge led them to consistently miss or ignore some observations that the other students consistently paid attention to. The analysis highlights the context sensitivity and potential fragility of coordination systems, and leads to the conclusion that students’ developing knowledge systems might not necessarily result in consistently improving performance.

  20. Coordination of knowledge in judging animated motion

    Science.gov (United States)

    Thaden-Koch, Thomas C.; Dufresne, Robert J.; Mestre, Jose P.

    2006-12-01

    Coordination class theory is used to explain college students’ judgments about animated depictions of moving objects. diSessa’s coordination class theory models a “concept” as a complex knowledge system that can reliably determine a particular type of information in widely varying situations. In the experiment described here, fifty individually interviewed college students judged the realism of two sets of computer animations depicting balls rolling on a pair of tracks. The judgments of students from an introductory physics class were strongly affected by the number of balls depicted (one or two), but the judgments of students from an educational psychology class were not. Coordination analysis of interview transcripts supports the interpretation that physics students’ developing physics knowledge led them to consistently miss or ignore some observations that the other students consistently paid attention to. The analysis highlights the context sensitivity and potential fragility of coordination systems, and leads to the conclusion that students’ developing knowledge systems might not necessarily result in consistently improving performance.

  1. Coordinating Group report

    International Nuclear Information System (INIS)

    1994-01-01

    In December 1992, western governors and four federal agencies established a Federal Advisory Committee to Develop On-site Innovative Technologies for Environmental Restoration and Waste Management (the DOIT Committee). The purpose of the Committee is to advise the federal government on ways to improve waste cleanup technology development and the cleanup of federal sites in the West. The Committee directed in January 1993 that information be collected from a wide range of potential stakeholders and that innovative technology candidate projects be identified, organized, set in motion, and evaluated to test new partnerships, regulatory approaches, and technologies which will lead to improve site cleanup. Five working groups were organized, one to develop broad project selection and evaluation criteria and four to focus on specific contaminant problems. A Coordinating Group comprised of working group spokesmen and federal and state representatives, was set up to plan and organize the routine functioning of these working groups. The working groups were charged with defining particular contaminant problems; identifying shortcomings in technology development, stakeholder involvement, regulatory review, and commercialization which impede the resolution of these problems; and identifying candidate sites or technologies which could serve as regional innovative demonstration projects to test new approaches to overcome the shortcomings. This report from the Coordinating Group to the DOIT Committee highlights the key findings and opportunities uncovered by these fact-finding working groups. It provides a basis from which recommendations from the DOIT Committee to the federal government can be made. It also includes observations from two public roundtables, one on commercialization and another on regulatory and institutional barriers impeding technology development and cleanup

  2. Resilient information networks for coordination of foodborne disease outbreaks.

    Science.gov (United States)

    Hossain, Liaquat; Hassan, Muhammad Rabiul; Wigand, Rolf T

    2015-04-01

    Foodborne disease outbreaks are increasingly being seen as a greater concern by public health authorities. It has also become a global research agenda to identify improved pathways to coordinating outbreak detection. Furthermore, a significant need exists for timely coordination of the detection of potential foodborne disease outbreaks to reduce the number of infected individuals and the overall impact on public health security. This study aimed to offer an effective approach for coordinating foodborne disease outbreaks. First, we identify current coordination processes, complexities, and challenges. We then explore social media surveillance strategies, usage, and the power of these strategies to influence decision-making. Finally, based on informal (social media) and formal (organizational) surveillance approaches, we propose a hybrid information network model for improving the coordination of outbreak detection.

  3. Hydrothermal synthesis and study of an inorganic-organic hybrid vanadate of a nickel(II) coordination complex with pyrazine, Ni{sub 3}(C{sub 4}H{sub 4}N{sub 2}){sub 3}(V{sub 8}O{sub 23})

    Energy Technology Data Exchange (ETDEWEB)

    Larrea, Edurne S. [Dpto. de Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain); Mesa, Jose L., E-mail: joseluis.mesa@ehu.es [Dpto. de Quimica Inorganica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain); Arriortua, Maria I. [Dpto. de Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain)

    2011-06-15

    Highlights: {yields} A novel inorganic-organic hybrid vanadate of nickel(II) coordination complex with pyrazine has been synthesized hydrothermally. {yields} The thermal and spectroscopic behavior has been studied. {yields} The compound shows AFM interactions which has been fitted to a magnetic model of lineal chains. -- Abstract: The three-dimensional hybrid compound Ni{sub 3}(C{sub 4}H{sub 4}N{sub 2}){sub 3}(V{sub 8}O{sub 23}) has been synthesized by mild hydrothermal methods under autogenous pressure at 170 {sup o}C. The structure of the phase is stable until 380 {sup o}C. The removal of the pyrazine molecules from the structure induces its collapse. The IR spectrum shows the vibration modes of the pyrazine molecule and those of the [VO{sub 4}]{sup 3-} groups. A UV-visible spectrum shows the characteristic bands of the Ni(II) d{sup 8}-high-spin cation in a slightly distorted octahedral coordination. Magnetic measurements indicate the existence of antiferromagnetic interactions that can be fitted with a chain model to give g = 2.31, J/k = -5.3, and zJ'/k = -5.5.

  4. Coordination chemistry and applications of versatile 4,5-diazafluorene derivatives.

    Science.gov (United States)

    Annibale, Vincent T; Song, Datong

    2016-01-07

    This perspective review will examine the coordination chemistry and applications of metal complexes of 4,5-diazafluorene derivatives. The versatile derivatives of 4,5-diazafluorene can serve multiple roles, and display a number of coordination modes. The ambidentate derivatives with multiple coordination sites can allow for the syntheses of coordination polymers, multimetallic, and macrocyclic complexes. In addition, certain 4,5-diazafluorene derivatives can serve as spectator ligands to support reactivity at the metal centre, or as reactive actor ligands engaging in atypical reactivity patterns. The applications of metal complexes of 4,5-diazafluorene derivatives in catalysis, photochemistry and photophysics, as well as in bioinorganic chemistry are also surveyed.

  5. Unusual metal coordination chemistry from an amino-amide derivative of 4-nitrophenol, a surprising ligand

    DEFF Research Database (Denmark)

    McGinley, John; McKee, Vickie; Toftlund, Hans

    2009-01-01

    The simple ligand N-(2-aminoethyl)-2-hydroxy-5-nitrobenzamide () exhibits several coordination modes depending on the reaction conditions, acting as a zwitterion on its own or being ionic in the presence of acid and depending on the concentration of metal present in a reaction, it can coordinate...... to the metal in either a 1:1 or a 1:2 metal:ligand mode. Furthermore, the role of solvent plays an important role in these complexation reactions with both four and six coordinate copper complexes being obtained using water as solvent but only six coordinate copper complexes obtained using acetonitrile...

  6. Copper (II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

    Copper(II) complexes with aroylhydrazones ... The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. ... EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic ...

  7. Developmental coordination disorder - literature review

    OpenAIRE

    Kosová, Blanka

    2015-01-01

    Title: Developmental coordination disorder - literature review Objectives: The theoretical part talks about developmental coordination disorder, its diagnosis, investigations, etiology and division during the different ages of the child. The practical part compares the studies relating to atypical development of motor skills in children with developmental coordination disorder. In diploma thesis was often used shortcut CKP and DCD, depending on the source from which it was drawn. DCD is the E...

  8. Synchronization matters for motor coordination.

    Science.gov (United States)

    Pesce Ibarra, Luigi S

    2018-03-01

    Using electroencephalography and electromyography recordings from healthy participants during a visual-depended bimanual coordination task, de Vries and colleagues showed that functional synchronization is important in motor coordination. The authors reported that higher coordination correlated positively with intermuscular synchrony, but correlated negatively with corticomuscular synchrony. They proposed that these two diverse motor systems operate differently depending on task demands. Similar experimental paradigms could identify motor mechanisms in patients with neurological disorders to design novel rehabilitation strategies.

  9. Pull Promotions and Channel Coordination

    OpenAIRE

    Eitan Gerstner; James D. Hess

    1995-01-01

    This paper recommends that manufacturers consider a pull price promotion as a coordination device in an independent channel of distribution. Uncoordinated decisions of both manufacturer and retailer to charge high prices can break down the effort to expand the market, resulting in losses to the channel as a whole. We show that manufacturers can enhance channel price coordination by designing pull price discounts that target price-conscious consumers. The increased price coordination improves ...

  10. Technetium and rhenium: coordination chemistry and nuclear medical applications

    OpenAIRE

    Abram,Ulrich; Alberto,Roger

    2006-01-01

    Coordination compounds of the radioactive element technetium are well established in diagnostic nuclear medicine, and various complexes of the gamma-emitting nuclide 99mTc are routinely used for organ imaging. Modern trends in the radiopharmaceutical chemistry of technetium focus on the 'labeling' of biologically active molecules such as peptides, steroids or other receptor-seeking units. This requires more knowledge about the coordination chemistry of the artificial transition metal, particu...

  11. Eye Hand Coordination in Children with Cerebral Palsy

    OpenAIRE

    Saavedra, Sandra; Joshi, Aditi; Woollacott, Marjorie; van Donkelaar, Paul

    2008-01-01

    Reaching to grasp an object of interest requires complex sensorimotor coordination involving eye, head, hand and trunk. While numerous studies have demonstrated deficits in each of these systems individually, little is known about how children with cerebral palsy (CP) coordinate multiple motor systems for functional tasks. Here we used kinematics, remote eye tracking and a trunk support device to examine the functional coupling of the eye, head and hand and the extent to which it was constrai...

  12. Coordination structure of adsorbed Zn(II) at Water-TiO2 interfaces

    Energy Technology Data Exchange (ETDEWEB)

    He, G.; Pan, G.; Zhang, M.; Waychunas, G.A.

    2011-01-15

    The local structure of aqueous metal ions on solid surfaces is central to understanding many chemical and biological processes in soil and aquatic environments. Here, the local coordination structure of hydrated Zn(II) at water-TiO{sub 2} interfaces was identified by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopy combined with density functional theory (DFT) calculations. A nonintegral coordination number of average {approx}4.5 O atoms around a central Zn atom was obtained by EXAFS analysis. DFT calculations indicated that this coordination structure was consistent with the mixture of 4-coordinated bidentate binuclear (BB) and 5-coordinated bidentate mononuclear (BM) metastable equilibrium adsorption (MEA) states. The BB complex has 4-coordinated Zn, while the monodentate mononuclear (MM) complex has 6-coordinated Zn, and a 5-coordinated adsorbed Zn was found in the BM adsorption mode. DFT calculated energies showed that the lower-coordinated BB and BM modes were thermodynamically more favorable than the higher-coordinated MM MEA state. The experimentally observed XANES fingerprinting provided additional direct spectral evidence of 4- and 5-coordinated Zn-O modes. The overall spectral and computational evidence indicated that Zn(II) can occur in 4-, 5-, and 6-oxygen coordinated sites in different MEA states due to steric hindrance effects, and the coexistence of different MEA states formed the multiple coordination environments.

  13. Studies on coordination chemistry and bioactivity of complexes of a bidentate oxygen-oxygen donor ligand, 1,2-dibenzoylhydrazine, with Cr3+, Co2+, Ni2+, Cu2+ and Zn2+ Ions

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Lai Wee Wong; Crouse, Karen A.; Ali, A.M.; Yamin, B.M.; Fun, H.-K.

    2003-08-01

    A new bidentate ligand, 1,2-dibenzoylhydrazine (DBHz), with OO donor sequences, was prepared. Several complexes of DBHz containing Cr(JJI), Fe(UI), Co(U), Ni(JJ), Cu(II) and Zn(TJ) ions have been synthesized and characterized by CHN analyses, IR, molar conductivity and UV/Visible spectroscopic studies. All of the compounds were tested for their antibacterial, antifungal and anticancer properties. DBHz was very effective against Pseudomonas aeruginosa, Bacillus subtilis mutant and Bacillus subtilis wild type bacteria. It was also effective against Saccaromyces cereiviceae, Candida albicans, Candida albicans lypolytica and Aspergillus ochraceous fungi. The free ligand, DBHz, in particular, was strongly active against colon cancer cell lines (HT-29), with a CD 50 value of 2.5 /μg/ml. (author)

  14. Wavefield extrapolation in caustic-free normal ray coordinates

    KAUST Repository

    Ma, Xuxin

    2012-11-04

    Normal ray coordinates are conventionally constructed from ray tracing, which inherently requires smooth velocity profiles. To use rays as coordinates, the velocities have to be smoothed further to avoid caustics, which is detrimental to the mapping process. Solving the eikonal equation numerically for a line source at the surface provides a platform to map normal rays in complex unsmoothed velocity models and avoid caustics. We implement reverse-time migration (RTM) and downward continuation in the new ray coordinate system, which allows us to obtain efficient images and avoid some of the dip limitations of downward continuation.

  15. Metal-dependent assembly of a tetranuclear copper(II) complex versus a 1D chain coordination polymer of cobalt(III) complex with N.sub.2./sub.O.sub.2./sub.-chelating Schiff-base ligand: Synthesis, characterization and crystal structures

    Czech Academy of Sciences Publication Activity Database

    Khalaji, A.D.; Hadadzadeh, H.; Fejfarová, Karla; Dušek, Michal

    2010-01-01

    Roč. 29, č. 2 (2010), s. 807-812 ISSN 0277-5387 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : Schiff bases * crystal structure * Jana2006 * coordination chemistry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.033, year: 2010

  16. Capital projects coordination

    Directory of Open Access Journals (Sweden)

    Zubović Jovan

    2004-01-01

    Full Text Available This paper looks at the difficulties of managing modem capital projects and endeavors to reduce the complexities to simpler and more understandable terms. It examines the project environment, defines project management and discusses points of difference from traditional management. In the second part of the paper are presented fundamentals for project success for different types of projects.

  17. Microsphere Assemblies via Phosphonate Monoester Coordination Chemistry.

    Science.gov (United States)

    Bladek, Kamila J; Reid, Margaret E; Nishihara, Hirotomo; Akhtar, Farid; Gelfand, Benjamin S; Shimizu, George K H

    2018-02-01

    By complexing a bent phosphonate monoester ligand with cobalt(II), coupled with in situ ester hydrolysis, coordination microspheres (CALS=CALgary Sphere) are formed whereas the use of the phosphonic acid directly resulted in a sheet-like structure. Manipulation of the synthetic conditions gave spheres with different sizes, mechanical stabilities, and porosities. Time-dependent studies determined that the sphere formation likely occurred through the formation of a Co 2+ and ligand chain that propagates in three dimensions through different sets of interactions. The relative rates of these assembly processes versus annealing by ester hydrolysis and metal dehydration determine the growth of the microspheres. Hardness testing by nanoindentation is carried out on the spheres and sheets. Notably, no templates or capping agents are employed, the growth of the spheres is intrinsic to the ligand geometry and the coordination chemistry of cobalt(II) and the phosphonate monoester. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Development of an International School Nurse Asthma Care Coordination Model.

    Science.gov (United States)

    Garwick, Ann W; Svavarsdóttir, Erla Kolbrun; Seppelt, Ann M; Looman, Wendy S; Anderson, Lori S; Örlygsdóttir, Brynja

    2015-03-01

    To identify and compare how school nurses in Reykjavik, Iceland and St. Paul, Minnesota coordinated care for youth with asthma (ages 10-18) and to develop an asthma school nurse care coordination model. Little is known about how school nurses coordinate care for youth with asthma in different countries. A qualitative descriptive study design using focus group data. Six focus groups with 32 school nurses were conducted in Reykjavik (n = 17) and St. Paul (n = 15) using the same protocol between September 2008 and January 2009. Descriptive content analytic and constant comparison strategies were used to categorize and compare how school nurses coordinated care, which resulted in the development of an International School Nurse Asthma Care Coordination Model. Participants in both countries spontaneously described a similar asthma care coordination process that involved information gathering, assessing risk for asthma episodes, prioritizing healthcare needs and anticipating and planning for student needs at the individual and school levels. This process informed how they individualized symptom management, case management and/or asthma education. School nurses played a pivotal part in collaborating with families, school and healthcare professionals to ensure quality care for youth with asthma. Results indicate a high level of complexity in school nurses' approaches to asthma care coordination that were responsive to the diverse and changing needs of students in school settings. The conceptual model derived provides a framework for investigators to use in examining the asthma care coordination process of school nurses in other geographic locations. © 2014 John Wiley & Sons Ltd.

  19. Identification of coordination factors affecting building projects performance

    Directory of Open Access Journals (Sweden)

    Wesam Salah Alaloul

    2016-09-01

    Full Text Available Construction projects performance requires improvement to fulfil the complexity of the stakeholders’ needs and expectations. Coordination process is proposed as an efficient solution for weak performance of construction projects. Therefore, coordination factors are vital in ensuring a successful implementation of all project phases. This study aimed to identify and prioritise coordination factors that influence the performance of building projects in Malaysian context. A vast body of literature on coordination process was reviewed and resulted in 53 coordination factor. Three rounds of Delphi technique were conducted. The most effective coordination factors were ranked based on the Relative Importance Index (RII such as Scheduling (RII = 0.97, Quality assurance plan (RII = 0.93, and all parties’ participation in plans (RII = 0.89. These coordination factors have fulfilled the research gap and provided better management and higher performance for project parties. The results offer insightful perspectives to define the most effective coordination factors, for addressing the dependency between project tasks and the parties to enhance project performance.

  20. Flexoelectricity via coordinate transformations

    Science.gov (United States)

    Stengel, Massimiliano

    2014-03-01

    Flexoelectricity describes the electric polarization that is linearly induced by a strain gradient, and is being intensely investigated as a tantalizing new route to converting mechanical stimulation into electrical signals and vice versa. While several breakthough experiments have been reported in the past few years, progress on the theoretical front has been comparatively slow, especially in the context of first-principles electronic-structure theory. The main difficulty with calculating the flexoelectric response of a material is the inherent breakdown of translational periodicity that a strain gradient entails, which at first sight questions the very applicability of traditional plane-wave pseudopotential methods. In this talk I will show how these obstacles can be overcome by combining density-functional perturbation theory with generalized coordinate transformations, gaining access to the full microscopic response (in terms of electronic charge density, polarization and atomic displacements) of a crystal or nanostructure to an arbitrary deformation field. As a practical demonstration, I will present results on the full flexoelectric response of a SrTiO3 film, including atomic relaxations and surface effects.

  1. Drug policy coordination: identifying and assessing dimensions of coordination.

    Science.gov (United States)

    Hughes, Caitlin Elizabeth; Ritter, Alison; Mabbitt, Nicholas

    2013-05-01

    Coordination has been recognised as a critical ingredient for successful drug policy governance. Yet what coordination means and how we assess the processes, outputs and outcomes of drug policy coordination is seldom defined. In this article we explore the utility of internationally recognised principles of good governance for examining aspects of drug policy coordination. We describe the development of an assessment tool, and pilot it in one context that has been both praised and criticised for its approach to drug policy coordination: Australia. Eight good governance principles of the United Nations Economic and Social Commission for Asia and the Pacific (which specify the need for policy processes to be participatory, responsive, equitable etc.), were adapted to drug policy coordination. A pilot survey was created to enable assessment of their perceived importance and perceived application and administered to 36 stakeholders from peak Australian advisory bodies. The instrument was shown to have high internal reliability and high face validity. Application to the Australian context suggested that the eight principles differed in importance, and that the most important principles were 'accountability' and 'participation'. Application also revealed perceived strengths and weaknesses in coordination, most notably, an apparent need to increase 'accountability' for stakeholder actions. The instrument requires further assessment of reliability and validity. Yet, at least within the Australian context, it starts to unpack normative statements about coordination to show perceptions of what coordination is, areas where improvement may be warranted and the degree of contestation amongst different players. Further application of the good governance lens within this and other contexts will progress the assessment of a fundamental yet neglected policy process and foster a more nuanced consideration of the possibilities for coordination in the drug policy "soup". Copyright

  2. Several novel N-donor tridentate ligands formed in chemical studies of new fac-Re(CO)3 complexes relevant to fac-99mTc(CO)3 radiopharmaceuticals: attack of a terminal amine on coordinated acetonitrile.

    Science.gov (United States)

    Perera, Theshini; Marzilli, Patricia A; Fronczek, Frank R; Marzilli, Luigi G

    2010-03-01

    To evaluate syntheses of fac-[Re(CO)(3)L](+) complexes in organic solvents, we treated fac-[Re(CO)(3)(CH(3)CN)(3)]PF(6)/BF(4) in acetonitrile with triamine ligands (L). When L had two primary or two tertiary terminal amine groups, the expected fac-[Re(CO)(3)L](+) complexes formed. In contrast, N,N-dimethyldiethylenetriamine (N,N-Me(2)dien) formed an unusual compound, fac-[Re(CO)(3)(DAE)]BF(4) {DAE = (Z)-N'-(2-(2-(dimethylamino)ethylamino)ethyl)acetimidamide = (Me(2)NCH(2)CH(2))NH(CH(2)CH(2)N=C(NH(2))Me)}. DAE is formed by addition of acetonitrile to the N,N-Me(2)dien terminal primary amine, converting this sp(3) nitrogen to an sp(2) nitrogen with a double bond to the original acetonitrile sp carbon. The three Ns bound to Re derive from N,N-Me(2)dien. The pathway to fac-[Re(CO)(3)(DAE)]BF(4) is suggested by a second unusual compound, fac-[Re(CO)(3)(MAE)]PF(6) {MAE = N-methyl-N-(2-(methyl-(2-(methylamino)ethyl)amino)ethyl)acetimidamide = MeN(H)-CH(2)CH(2)-N(Me)-CH(2)CH(2)-N(Me)-C(Me)=NH}, isolated after treating fac-[Re(CO)(3)(CH(3)CN)(3)]PF(6) with N,N',N''-trimethyldiethylenetriamine (N,N',N''-Me(3)dien). MAE chelates via a terminal and a central sp(3) N from N,N',N''-Me(3)dien and via one sp(2) NH in a C(Me)=NH group. This group is derived from acetonitrile by addition of the other N,N',N''-Me(3)dien terminal amine to the nitrile carbon. This addition creates an endocyclic NMe group within a seven-membered chelate ring. The structure and other properties of fac-[Re(CO)(3)(MAE)]PF(6) allow us to propose a reaction scheme for the formation of the unprecedented DAE ligand. The new compounds advance our understanding of the spectral and structural properties of Re analogues of (99m)Tc radiopharmaceuticals.

  3. Novel rare earth quinolinolate complexes

    International Nuclear Information System (INIS)

    Deacon, Glen B.; Forsyth, Craig M.; Junk, Peter C.; Kynast, Ulrich; Meyer, Gerd; Moore, Joanne; Sierau, Jennyfer; Urbatsch, Aron

    2008-01-01

    The reaction of europium 8-quinolinolate Eu(OQ) 3 with calcium 8-quinolinolate, Ca(OQ) 2 , in the flux 1,2,4,5-tetramethylbenzene (TMB) at 210 deg. C yields the bimetallic [Eu 2 Ca(OQ) 8 ], which is a linear tri-nuclear complex with two eight coordinate europium atoms flanking a six coordinate calcium atom bonded by six bridging phenolate oxygen atoms. A similar reaction between La(OQ) 3 and Co(OQ) 2 gave [LaCo 2 (OQ) 7 ], in which two six coordinate cobalt atoms flank an eight coordinate lanthanum atom with six bridging phenolate oxygen atoms and a terminal OQ group

  4. Coordination of Conditional Poisson Samples

    Directory of Open Access Journals (Sweden)

    Grafström Anton

    2015-12-01

    Full Text Available Sample coordination seeks to maximize or to minimize the overlap of two or more samples. The former is known as positive coordination, and the latter as negative coordination. Positive coordination is mainly used for estimation purposes and to reduce data collection costs. Negative coordination is mainly performed to diminish the response burden of the sampled units. Poisson sampling design with permanent random numbers provides an optimum coordination degree of two or more samples. The size of a Poisson sample is, however, random. Conditional Poisson (CP sampling is a modification of the classical Poisson sampling that produces a fixed-size πps sample. We introduce two methods to coordinate Conditional Poisson samples over time or simultaneously. The first one uses permanent random numbers and the list-sequential implementation of CP sampling. The second method uses a CP sample in the first selection and provides an approximate one in the second selection because the prescribed inclusion probabilities are not respected exactly. The methods are evaluated using the size of the expected sample overlap, and are compared with their competitors using Monte Carlo simulation. The new methods provide a good coordination degree of two samples, close to the performance of Poisson sampling with permanent random numbers.

  5. Coordinate-Free Rotation Operator.

    Science.gov (United States)

    Leubner, C.

    1979-01-01

    Suggests the use of a coordinate-free rotation operator for the teaching of rotations in Euclidean three space because of its twofold didactic advantage. Illustrates the potentialities of the coordinate-free rotation operator approach by a number of examples. (Author/GA)

  6. Coordinated Transportation: Problems and Promise?

    Science.gov (United States)

    Fickes, Michael

    1998-01-01

    Examines the legal, administrative, and logistical barriers that have prevented the wide acceptance of coordinating community and school transportation services and why these barriers may be breaking down. Two examples of successful implementation of coordinated transportation are examined: employing a single system to serve all transportation…

  7. Introduction to coordinated linear systems

    NARCIS (Netherlands)

    Kempker, P.L.

    2014-01-01

    This chapter serves as an introduction to the concepts of coordinated linear systems, in formal as well as intuitive terms. The concept of a coordinated linear system is introduced and formulated, and some basic properties are derived, providing both a motivaton and a formal basis for the following

  8. Transformation optics in orthogonal coordinates

    OpenAIRE

    Chen, Huanyang

    2008-01-01

    The author proposes the methodology of transformation optics in orthogonal coordinates to obtain the material parameters of the transformation media from the mapping in orthogonal coordinates. Several examples are given to show the applications of such a methodology by using the full-wave simulations.

  9. Bare coordination: the semantic shift

    NARCIS (Netherlands)

    de Swart, Henriette|info:eu-repo/dai/nl/074764187; Le Bruyn, Bert|info:eu-repo/dai/nl/30484912X

    2014-01-01

    This paper develops an analysis of the syntax-semantics interface of two types of split coordination structures. In the first type, two bare singular count nouns appear as arguments in a coordinated structure, as in bride and groom were happy. We call this the N&N construction. In the second type,

  10. White-light phosphorescence from binary coordination polymer nanoparticles

    International Nuclear Information System (INIS)

    Qin, Lijie; Zhu, Yachao; Yang, Hong; Ding, Liang; Sun, Feng; Shi, Mei; Yang, Shiping

    2013-01-01

    Phosphorescent nanoscale coordination polymer nanoparticles (NCPs) were conveniently synthesized by phosphorescent carboxyl-functionalized iridium complexes as a building block and rare earth Y(III) ions as metallic nodes. They reveal to be uniform nanospheres with average diameter around 200 nm. Multi-color emission from blue to orange was obtained by tuning the ratios of two iridium complexes with energy transfer between them. Furthermore, the white-light emission with CIE coordinates of (0.319, 0.388) was performed. - Highlights: ► Phosphorescent nanoscale coordination polymer nanoparticles (NCPs) were conveniently synthesized. ► The phosphorescent carboxyl-functionalized iridium complex was a building block with rare earth Y(III) ions as metallic nodes. ► Multi-color emission from blue to orange was obtained

  11. Increased coordination in public transport – which mechanisms are available?

    DEFF Research Database (Denmark)

    Sørensen, Claus Hedegaard; Longva, Frode

    2011-01-01

    and suggested to increase coordination between core stakeholders within passenger railway services and bus services. Four distinctive mechanisms of coordination are suggested, namely organisational coordination, contractual coordination, partnership coordination and discursive coordination. Each coordination...

  12. Archimedes' principle in general coordinates

    International Nuclear Information System (INIS)

    Ridgely, Charles T

    2010-01-01

    Archimedes' principle is well known to state that a body submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body. Herein, Archimedes' principle is derived from first principles by using conservation of the stress-energy-momentum tensor in general coordinates. The resulting expression for the force is applied in Schwarzschild coordinates and in rotating coordinates. Using Schwarzschild coordinates for the case of a spherical mass suspended within a perfect fluid leads to the familiar expression of Archimedes' principle. Using rotating coordinates produces an expression for a centrifugal buoyancy force that agrees with accepted theory. It is then argued that Archimedes' principle ought to be applicable to non-gravitational phenomena, as well. Conservation of the energy-momentum tensor is then applied to electromagnetic phenomena. It is shown that a charged body submerged in a charged medium experiences a buoyancy force in accordance with an electromagnetic analogue of Archimedes' principle.

  13. Archimedes' principle in general coordinates

    Science.gov (United States)

    Ridgely, Charles T.

    2010-05-01

    Archimedes' principle is well known to state that a body submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body. Herein, Archimedes' principle is derived from first principles by using conservation of the stress-energy-momentum tensor in general coordinates. The resulting expression for the force is applied in Schwarzschild coordinates and in rotating coordinates. Using Schwarzschild coordinates for the case of a spherical mass suspended within a perfect fluid leads to the familiar expression of Archimedes' principle. Using rotating coordinates produces an expression for a centrifugal buoyancy force that agrees with accepted theory. It is then argued that Archimedes' principle ought to be applicable to non-gravitational phenomena, as well. Conservation of the energy-momentum tensor is then applied to electromagnetic phenomena. It is shown that a charged body submerged in a charged medium experiences a buoyancy force in accordance with an electromagnetic analogue of Archimedes' principle.

  14. Enterprise Coordination on the Internet

    Directory of Open Access Journals (Sweden)

    Charles Petrie

    2011-02-01

    Full Text Available Enterprises are now connected internally and externally to other Enterprises via the Internet in ways that are increasingly difficult to manage, especially as these interconnections become more dynamic. Current methods of coordinating the effects of change as they propagate through these networks of connections are not likely to scale. What is needed is a new paradigm for how the Internet supports such coordination. Indeed, the Internet should and could provide fundamental coordination functions that are missing today. In this paper, we describe how such a “Coordinated Internet” would work (this paper is an expanded version of [1]. The key functionality of a Coordinated Internet would be that the Internet actively watches what people do (analogous to search completion on desktops today, correlates these activities, and actively notifies people when and how their current tasks affect and are affected by the activities of other people. This would be accomplished by standard coordination functions implemented as a common Internet layer that can be used as a utility by more specialized applications. Such a Coordinated Internet would revolutionize enterprise management, for all enterprises, large and small, corporate and personal. For example, static workflows would become obsolete for all but the the most routine processes. Some solutions provide existence proofs of such a coordination substrate, such as the Redux solution in concurrent engineering, which we describe herein. However, foundational research remains to be done in the new field of Coordination Engineering in order to reach the goal of a future Internet in which coordination functions are fundamental.

  15. Superluminal coordinate transformations: Four-dimensional case

    Science.gov (United States)

    Marchildon, Louis; Antippa, Adel F.; Everett, Allen E.

    1983-04-01

    We investigate, from a group-theoretical point of view, the possibility of implementing the so-called extended principle of relativity. This consists in postulating that the set of all equivalent reference frames contains frames whose relative velocities are larger than c, in addition to those whose coordinates are related by proper orthochronous Lorentz transformations. We show that implementing the extended principle of relativity by means of either real or complex linear transformations results in strong conflicts with experiment and/or intractable problems of interpretation. We then briefly analyze alternative approaches to four-dimensional superluminal transformations, in which the extended principle of relativity is either weakened or completely abandoned.

  16. Engineering the oxygen coordination in digital superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Seyoung [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Department of Materials Science, Northwestern University, Evanston, Illinois 60202, USA; Andersen, Tassie K. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Department of Materials Science, Northwestern University, Evanston, Illinois 60202, USA; Hong, Hawoong [X-Ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Rosenberg, Richard A. [X-Ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA; Marks, Laurence D. [Department of Materials Science, Northwestern University, Evanston, Illinois 60202, USA; Fong, Dillon D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

    2017-12-01

    The oxygen sublattice in the complex oxides is typically composed of corner-shared polyhedra, with transition metals at their centers. The electronic and chemical properties of the oxide depend on the type and geometric arrangement of these polyhedra, which can be controlled through epitaxial synthesis. Here, we use oxide molecular beam epitaxy to create SrCoOx:SrTiO3 superlattices with tunable oxygen coordination environments and sublattice geometries. Using soft X-ray spectroscopy, we find that the chemical state of Co can be varied with the polyhedral arrangement, demonstrating a new strategy for achieving unique electronic properties in the transition metal oxides.

  17. Keep Meaning in Conversational Coordination

    Directory of Open Access Journals (Sweden)

    Elena Clare Cuffari

    2014-12-01

    Full Text Available Coordination is a widely employed term across recent quantitative and qualitative approaches to intersubjectivity, particularly approaches that give embodiment and enaction central explanatory roles. With a focus on linguistic and bodily coordination in conversational contexts, I review the operational meaning of coordination in recent empirical research and related theorizing of embodied intersubjectivity. This discussion articulates what must be involved in treating linguistic meaning as dynamic processes of coordination. The coordination approach presents languaging as a set of dynamic self-organizing processes and actions on multiple timescales and across multiple modalities that come about and work in certain domains (those jointly constructed in social, interactive, high-order sense-making. These processes go beyond meaning at the level that is available to first-person experience. I take one crucial consequence of this to be the ubiquitously moral nature of languaging with others. Languaging coordinates experience, among other levels of behavior and event. Ethical effort is called for by the automatic autonomy-influencing forces of languaging as coordination.

  18. Workshop for Coordinators/Assistants/Alternate Coordinators of IAEA Projects

    International Nuclear Information System (INIS)

    2009-01-01

    The objectives of the workshop was to discuss the roles and responsibilities of IAEA projects co-coordinators and the challenges they encounter in the implementation of such projects. Solutions were suggested.(Lead Record)

  19. Coordinating distributed work : Exploring situated coordination with gaming-simulation

    NARCIS (Netherlands)

    van Laere, J.

    2003-01-01

    Organizational work has become more and more distributed nowadays. Information and communication technologies (ICT) provide opportunities to improve coordination of distributed work, but in practice many organizations struggle with integrating new organizational structures, new work practices and

  20. Coordinate Mastering Using Optical Coupling

    Science.gov (United States)

    Bieman, Leonard H.

    1989-01-01

    For a multi-sensor machine vision system, relating each sensor's measurement to a master gage coordinate system has been a difficult task. This is especially true for sheet metal gaging in the automotive industry where sensors may be separated by four or five meters. The current approach used to establish this master coordinate system, which is difficult at best, has been the following. First, the part is placed in the gage. The exact location, that is being measured by each sensor, is marked on the part. Then the marked part is transported to a coordinate measuring machine (CMM), where the location of each of the marked points is measured. These CMM measurements establish a master coordinate system. The procedure just described has major drawbacks including: the accuracy of marking the exact location being measured; the sensors orientation must be known with respect to the master coordinate system; and deformation of the sheet metal part when it is transported to the CMM. The mastering process can be significantly improved by optical coupling a theodolite pair with each machine vision sensor. This optical coupling is established by locating a target in a position that can be accurately measured by both a sensor and the theodolite system. First, the theodolite system is calibrated in gage coordinates by sighting on reference points placed on the machine vision gage. Then, for each sensor, the target location is measured by both the sensor and theodolite pair at three or more positions (or alternately one target may have three or more points that can be measured). From this data, the transforms from sensor coordinates to gage coordinates can be calculated. This report will present the configuration and calculations for coordinate mastering using optical coupling.

  1. Nitrido complexes of technetium

    International Nuclear Information System (INIS)

    Abram, U.; Abram, S.

    1987-01-01

    In this report synthesis, characterization and chemical behaviour of coordination compounds of the element technetium are reported containing a geminal nitrogen ligand. In addition, an evaluation of the in-vitro behaviour of the complexes is given as well as a list of all literature to this matter. (author)

  2. Evaluating the Relational Coordination instrument

    DEFF Research Database (Denmark)

    Edwards, Kasper; Lundstrøm, Sanne Lykke

    2014-01-01

    and surgical performance. This has prompted the attention of both practitioners and politicians some of who perceive relational coordination as a means to attain better performance. The relational coordination instrument has been validated as a measure of teamwork from the following perspectives: internal...... consistency, interrater agreement and reliability, structural validity, content validity. However as relational coordination is being used as a diagnostics tool it is important to examine further if the instrument can measure changes. Indeed we need to know how precise and sensitive the instrument is when...

  3. Insulation coordination workstation for AC and DC substations

    International Nuclear Information System (INIS)

    Booth, R.R.; Hileman, A.R.

    1990-01-01

    The Insulation Coordination Workstation was designed to aid the substation design engineer in the insulation coordination process. The workstation utilizes state of the art computer technology to present a set of tools necessary for substation insulation coordination, and to support the decision making process for all aspects of insulation coordination. The workstation is currently being developed for personal computers supporting OS/2 Presentation Manager. Modern Computer-Aided Software Engineering (CASE) technology was utilized to create an easily expandable framework which currently consists of four modules, each accessing a central application database. The heart of the workstation is a library of user-friendly application programs for the calculation of important voltage stresses used for the evaluation of insulation coordination. The Oneline Diagram is a graphic interface for data entry into the EPRI distributed EMTP program, which allows the creation of complex systems on the CRT screen using simple mouse clicks and keyboard entries. Station shielding is graphically represented in the Geographic Viewport using a three-dimensional substation model, and the interactive plotting package allows plotting of EPRI EMTP output results on the CRT screen, printer, or pen plotter. The Insulation Coordination Workstation was designed by Advanced Systems Technology (AST), a division of ABB Power Systems, Inc., and sponsored by the Electric Power Research Institute under RP 2323-5, AC/DC Insulation Coordination Workstation

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  5. Large-deformation modal coordinates for nonrigid vehicle dynamics

    Science.gov (United States)

    Likins, P. W.; Fleischer, G. E.

    1972-01-01

    The derivation of minimum-dimension sets of discrete-coordinate and hybrid-coordinate equations of motion of a system consisting of an arbitrary number of hinge-connected rigid bodies assembled in tree topology is presented. These equations are useful for the simulation of dynamical systems that can be idealized as tree-like arrangements of substructures, with each substructure consisting of either a rigid body or a collection of elastically interconnected rigid bodies restricted to small relative rotations at each connection. Thus, some of the substructures represent elastic bodies subjected to small strains or local deformations, but possibly large gross deformations, in the hybrid formulation, distributed coordinates referred to herein as large-deformation modal coordinates, are used for the deformations of these substructures. The equations are in a form suitable for incorporation into one or more computer programs to be used as multipurpose tools in the simulation of spacecraft and other complex electromechanical systems.

  6. Coordinating a successful discharge plan.

    Science.gov (United States)

    Hester, L E

    1996-06-01

    Whether you're working with a team or serving as liaison to a specially designated home care coordinator, your role is crucial in paving the way home for your patient. Here are the essential steps to take.

  7. Who matters in coordination problems?

    Czech Academy of Sciences Publication Activity Database

    Sákovics, J.; Steiner, Jakub

    2012-01-01

    Roč. 102, č. 7 (2012), s. 3439-3461 ISSN 0002-8282 Institutional support: RVO:67985998 Keywords : coordination problem s * heterogeneous agents Subject RIV: AH - Economics Impact factor: 2.792, year: 2012

  8. The Role of a Burn Research Coordinator: A Guide for Novice Coordinators.

    Science.gov (United States)

    Honari, Shari; Caceres, Maria; Romo, Mariana; Gibran, Nicole S; Gamelli, Richard L

    2016-01-01

    As health-care complexity and costs increase, evidence-based research has become essential to the advancement of burn care. Multicenter trials involve procedures, regulations, and guidelines that require meticulous attention to details and strict adherence to compliance issues. Taking on a large, multicenter trial can be a daunting task for a new burn research coordinator. The purpose of this article is to provide a resource for new burn research coordinators in multicenter clinical trial planning, especially in the field of burns. The burn research coordinator must possess organizational and multitasking skills, attention to detail, professionalism, initiative, and motivation. The burn research coordinator must exercise five principles of practice: compliance, confidentiality, consistency and correctness, and collaboration. Compliance assures subject safety, study integrity, and burn center reputation. Confidentiality is essential, especially when handling sensitive health information. Maintaining subject privacy through secure links and destruction of linked data in a timely matter protects the subjects and complies with the regulations of many governing bodies. Consistency and correctness minimize human errors through continuous data validation and self-auditing and peer auditing. Collaboration between the Principal Investigator/burn research coordinator and all departments involved in the study maintains the study focus and allows for enforcement of procedures. Preparing a budget confirms adequate compensation for work done by the research team and can be broken down into the following five steps: protocol review, calculation of initial payment, establishment of indirect costs, calculation of direct costs, and budget negotiation. Over time, one becomes familiar with the details involved with study success. Advocating for subject safety and protocol adherence are of highest priority. Study design is the most important element that dictates the success of the

  9. Coordination theory and collaboration technology

    CERN Document Server

    Olson, Gary M; Smith, John B

    2001-01-01

    The National Science Foundation funded the first Coordination Theory and Collaboration Technology initiative to look at systems that support collaborations in business and elsewhere. This book explores the global revolution in human interconnectedness. It will discuss the various collaborative workgroups and their use in technology. The initiative focuses on processes of coordination and cooperation among autonomous units in human systems, in computer and communication systems, and in hybrid organizations of both systems. This initiative is motivated by three scientific issues which have been

  10. Muscle Activation and Movement Coordination.

    OpenAIRE

    Ljung, Carl

    2014-01-01

    The purpose of this project was to empirically develop a method of using electromyography to identify how humans coordinate their muscles during certain sequences of movement and the effect of an injured anterior cruciate ligament to muscle coordination. In this study, more simple movements of the lower extremities are examined and relatively accurate hypothesizes can be made solely based on anatomical theory. However, a general method for electromyographic studies would open up the possibili...

  11. DEVELOPMENTAL COORDINATION DISORDER IN CHILDREN

    OpenAIRE

    Saeideh MIRAFKHAMI; Seyyed Hossein FAKHRAEE; Sina MIRAFKHAMI; Mojtaba YOUSEFI; Mona VARZANDEH FAR

    2010-01-01

    ObjectiveIn this article, a motor skill disorder called developmental coordination disorder (DCD), that is usually first diagnosed during childhood, is explained and discussed. In the year 1987, DCD was formally recognized as a distinct disorder in children by the American Psychiatric Association  (APA). DCD is a generalized term for the children who have some degrees of impairment in the development of motor coordination and therefore have difficulties with physical skills which significantl...

  12. Path integrals in curvilinear coordinates

    International Nuclear Information System (INIS)

    Prokhorov, L.V.

    1984-01-01

    Integration limits are studied for presenting the path integral curvilinear coordinates. For spherical (and topoloqically equivalent) coordinates it is shown that in formulas involving classical action in the exponent integration over all variables should be carried out within infinite limits. Another peculiarity is associated with appearance of the operator q which provides a complete definition of the wave functions out of the physical region. arguments are given upporting the validity of the cited statament in the general case

  13. Accelerating fourier volume rendering by polar coordinate data representation.

    Science.gov (United States)

    Liao, Jan-Ray; Lee, Shun-Zhi; Lee, Huai-Che

    2012-12-01

    Volume rendering is an important tool to visualize three-dimensional data in biomedicine by projecting the data to a two-dimensional plane. The projection is done by ray casting and its complexity is proportional to the number of three-dimensional data points. To reduce complexity, Fourier volume rendering (FVR) uses slice projection theorem to facilitate the integration of voxels along the ray casting path. In this paper, we proposed a new method for FVR that stored and processed the frequency domain data in polar coordinate. By exploiting three aspects of data processing which is previously impossible in rectilinear coordinate, our new method is much faster than the previous methods. The first aspect is data regularity. When data are stored in polar coordinate, extracting a slice involves accessing data stored in adjacent memory location. This regularity makes memory access more efficient. The second aspect is to utilize the high data density near the origin in polar coordinate. We can obtain two benefits from this aspect. The first allows us to extract a slice by nearest-neighbor interpolation instead of more complex interpolation but without sacrificing image quality. The second allows us to trade off between image quality and memory storage. The third aspect is to recognize that converting from rectilinear coordinate to polar coordinate is a one-time process. Therefore, we can use a better interpolation kernel with larger support in coordinate conversion. In turn, most of the computation is shifted to the preprocessing stage and interactive rendering can be made very fast. In the experiments, we show that the speed in interactive visualization for our new method is independent of the size of the interpolation kernel, therefore, achieving comparable image quality at a faster rate than previous methods. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  14. Motor coordination uses external spatial coordinates independent of developmental vision.

    Science.gov (United States)

    Heed, Tobias; Röder, Brigitte

    2014-07-01

    The constraints that guide bimanual movement coordination are informative about the processing principles underlying movement planning in humans. For example, symmetry relative to the body midline benefits finger and hand movements independent of hand posture. This symmetry constraint has been interpreted to indicate that movement coordination is guided by a perceptual code. Although it has been assumed implicitly that the perceptual system at the heart of this constraint is vision, this relationship has not been tested. Here, congenitally blind and sighted participants made symmetrical and non-symmetrical (that is, parallel) bimanual tapping and finger oscillation movements. For both groups, symmetrical movements were executed more correctly than parallel movements, independent of anatomical constraints like finger homology and hand posture. For the blind, the reliance on external spatial factors in movement coordination stands in stark contrast to their use of an anatomical reference frame in perceptual processing. Thus, the externally coded symmetry constraint evident in bimanual coordination can develop in the absence of the visual system, suggesting that the visual system is not critical for the establishment of an external-spatial reference frame in movement coordination. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. An Integrative Perspective on Interpersonal Coordination in Interactive Team Sports

    Science.gov (United States)

    Steiner, Silvan; Macquet, Anne-Claire; Seiler, Roland

    2017-01-01

    Interpersonal coordination is a key factor in team performance. In interactive team sports, the limited predictability of a constantly changing context makes coordination challenging. Approaches that highlight the support provided by environmental information and theories of shared mental models provide potential explanations of how interpersonal coordination can nonetheless be established. In this article, we first outline the main assumptions of these approaches and consider criticisms that have been raised with regard to each. The aim of this article is to define a theoretical perspective that integrates the coordination mechanisms of the two approaches. In doing so, we borrow from a theoretical outline of group action. According to this outline, group action based on a priori shared mental models is an example of how interpersonal coordination is established from the top down. Interpersonal coordination in reaction to the perception of affordances represents the bottom-up component of group action. Both components are inextricably involved in the coordination of interactive sports teams. We further elaborate on the theoretical outline to integrate a third, constructivist approach. Integrating this third approach helps to explain interpersonal coordination in game situations for which no shared mental models are established and game situations that remain ambiguous in terms of perceived affordances. The article describes how hierarchical, sequential, and complex dimensions of action organization are important aspects of this constructivist perspective and how mental models may be involved. A basketball example is used to illustrate how top-down, bottom-up and constructivist processes may be simultaneously involved in enabling interpersonal coordination. Finally, we present the implications for research and practice. PMID:28894428

  16. A simple coordination complex exhibiting colour change on slight ...

    Indian Academy of Sciences (India)

    Administrator

    The SMART software was used for the intensity data acquisition and the. SAINT PLUS software was used for data extraction. In each case, Data reduction was done by. SAINTPLUS,. 15 absorption correction by using an empirical method SADABS,. 16 structure solution using SHELXS-97,. 17 and refined using SHELXL-.

  17. Carboxylate-bridged Cu (II) coordination polymeric complex ...

    Indian Academy of Sciences (India)

    BIG was formed by the reaction of Cu(ClO₄)₂ ·6H₂O and tridentate benzimidazole-glycine conjugate ligand, 2-((1H-benzimidazol- 2-yl)methylamino) acetic acid, BIGH and its structure has been determined by IR, UV, powder XRD, VSM, CV, ...

  18. A simple coordination complex exhibiting colour change on slight ...

    Indian Academy of Sciences (India)

    Administrator

    believe that this slight structural modification is responsible for this colour change from blue violet. (compound 1) to straw yellow (compound 2). References. 1. Corey E J and Bailar Jun J C 1959 J. Am. Chem. Soc. 81 2620. 2. Gollogly J R and Hawkins C J 1967 Aust. J. Chem. 20 2395. 3. Gollogly J R and Hawkins C J 1969 ...

  19. English cum, a borrowed coordinator turned complex-compound marker

    OpenAIRE

    Renner, Vincent

    2013-01-01

    International audience; This article takes issue with the traditional view of English compounds such as governess-cum- piano-teacher, according to which the medial morpheme -cum- is insignificant. The study is first centered on the appearance of the linking element in the English language. New insight into its distribution and function is then provided by scrutinizing a list of 259 compounds extracted from a present-day newspaper corpus. It is found that -cum- appears exclusively in non-insti...

  20. Carboxylate-bridged Cu(II) coordination polymeric complex ...

    Indian Academy of Sciences (India)

    SABITHAKALA THATITURI

    BIG was formed by the reaction ... researchers, for their potential application as advanced .... Crystallographic data and structure refinement parameters are presented in. Table 1. Table 1. Crystal data and structure refinement details for Cu-BIG.

  1. Molecular nanomagnetism in actinide-based coordination complexes

    International Nuclear Information System (INIS)

    Caciuffo, R.; Colineau; Magnani, N.; Santini, G.; Amoretti, S.; Carretta, P.; Mougel, J.; Pécaut, L.; Chatelain, S.; Gambarelli, J.; Hermle, M.; Mazzanti, V.; Degeyer, A.; Tuna, E.F.

    2014-01-01

    We present very recent results obtained for a hetero-metallic U(V)-Mn(II) one-dimensional chain assembled through cation-cation interactions , and for a triangular molecule containing three U(V)O2+ (5f1) ions . The former is the first example of an actinidecontaining single-chain magnet (SCM), with a relaxation barrier of 134 K, a blocking temperature of 6 K, and an impressive coercive field Bc = 3.4 tesla at 2 K. The latter is characterized by a non-magnetic ground doublet corresponding to two oppositely twisted chiral arrangements of the U moments, and (in presence of a magnetic field orthogonal to the triangle plane) by quantum tunnelling of the noncollinear magnetization accompanied by oscillations of the anapole (toroidal) moment

  2. Cobalt(II) and Cobalt(III) Coordination Compounds.

    Science.gov (United States)

    Thomas, Nicholas C.; And Others

    1989-01-01

    Presents a laboratory experiment which illustrates the formation of tris(phenanthroline)cobalt complexes in the 2+ and 3+ oxidation states, the effect of coordination on reactions of the ligand, and the use of a ligand displacement reaction in recovering the transformed ligand. Uses IR, UV-VIS, conductivity, and NMR. (MVL)

  3. Steric control of the coordination mode of thiosemicarbazone ...

    Indian Academy of Sciences (India)

    Administrator

    ) has been observed in a series of complexes of type [M(PPh3)2(bztsc-R)2] (M = Ru, Os) obtained from the reaction of the ligands with [M(PPh3)2X2] (X = Cl, Br). Assuming the bulk of PPh3 to be responsible for such a coordination mode, ...

  4. Ruthenium-based four-coordinate olefin metathesis catalysts

    International Nuclear Information System (INIS)

    Sanford, M.S.; Henling, L.M.; Day, M.W.; Grubbs, R.H.

    2000-01-01

    A series of four-coordinate Ru II alkylidenes has been prepared as analogues of the proposed olefin metathesis intermediate [(PCy 3 )Cl 2 Ru=CHPh]. These complexes exhibit unusual trigonal-pyramidal solid-state geometries, and are rendered highly active for ring-closing metathesis by the addition of HCl. (orig.)

  5. Ruthenium-based four-coordinate olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, M.S.; Henling, L.M.; Day, M.W.; Grubbs, R.H. [California Inst. of Tech., Pasadena (United States). Div. of Chemistry and Chemical Engineering

    2000-10-02

    A series of four-coordinate Ru{sup II} alkylidenes has been prepared as analogues of the proposed olefin metathesis intermediate [(PCy{sub 3})Cl{sub 2}Ru=CHPh]. These complexes exhibit unusual trigonal-pyramidal solid-state geometries, and are rendered highly active for ring-closing metathesis by the addition of HCl. (orig.)

  6. Using Cultures and Values to Support Flexible Coordination

    NARCIS (Netherlands)

    Vanhée, L.C.B.C.

    2015-01-01

    This thesis proposes a method for supporting flexible coordination in multi-agent systems (MASs). In other words, we aim at influencing societies of artificial agents such that they can handle complex and evolving environments and collective goals (emergency rescue robots capable of handling various

  7. Co-ordinating humanitarian operations in peace support missions

    NARCIS (Netherlands)

    Rietjens, S.J.H.; Voordijk, Johannes T.; de Boer, S.J.

    2007-01-01

    Purpose – This paper seeks to contribute to a more effective co-ordination of humanitarian operations by military and civilian organizations involved in a peace support mission in response to a complex emergency. Design/methodology/approach – The information processing view, in particular

  8. Formal-Language-Theoretic Control & Coordination of Mobile Robots

    National Research Council Canada - National Science Library

    Ray, Asok

    2007-01-01

    ... of formal-language-theoretic models instead of ad-hoc rule-based expert systems. Future Plans: 1) Formulation of operational intelligence models in a formal-language-theoretic setting. 2) Algorithm development for intelligent coordination of autonomous agent teams to accomplish complex mission tasks.

  9. Heterotrimetallic complexes in molecular magnetism.

    Science.gov (United States)

    Andruh, Marius

    2018-04-05

    This paper reviews the most representative examples of heterometallic complexes containing three different paramagnetic metal ions, focusing on their magnetic properties. These compounds show a rich structural variety, ranging from discrete species to coordination polymers of various dimensionalities. The general synthetic strategies leading to heterotrimetallic complexes are discussed and illustrated.

  10. Candmium complexes with aroyl hydrazones

    International Nuclear Information System (INIS)

    Biradar, N.S.; Mahale, V.B.; Havinale, B.R.

    1976-01-01

    Eight complexes of Cd(II) have been prepared by reacting cadmium acetate with aroyl hydrazones in aqueous ethanolic medium. The elemental analyses indicate 1:2 stoichiometry. On the basis of infrared spectral studies, it has been shown that the ligands react in the keto form and the complexes have coordination number six. (author)

  11. Copper complexes as chemical nucleases

    Indian Academy of Sciences (India)

    Unknown

    Chemical nucleases are redox active coordination complexes that cleave DNA by an oxidative pathway. ... with a reductant like ascorbate, reduced glutathione or NADH in DNA strand breaking giving the order T > G > C > A 16,17. .... The emission intensity of CT DNA-bound ethidium bromide (12⋅5 µM) at different complex ...

  12. A two-dimensional molybdenum (V) phosphate with covalently bonded transition metal coordination complexes: hydrothermal synthesis and structure characterization of Na 2[{Mn(phen) 2(H 2O)}{Mn(phen) 2} 3{Mn Mo 12vO 24 (HPO 4) 6(PO 4) 2(OH) 6}]·4H 2O (phen=1, 10-phenanthroline)

    Science.gov (United States)

    Yuan, Mei; Wang, Enbo; Lu, Ying; Li, Yangguang; Hu, Changwen; Hu, Ninghai; Jia, Hengqing

    2003-01-01

    An organic-inorganic hybrid molybdenum phosphate, Na 2[{Mn(phen) 2(H 2O)} {Mn(phen) 2} 3{MnMo 12vO 24 (HPO 4) 6(PO 4) 2(OH) 6}]·4H 2O (phen=1,10-phenanthroline), involving molybdenum present in V oxidation state and covalently bonded transition metal coordination complexes, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P 1¯, a=16.581(1) Å, b=18.354(1) Å, c=24.485(2) Å, α=80.589(1)°, β=71.279(1)°, γ=67.084(1)°, V=6493.8(8) Å 3, Z=2, λ(Mo Kα)=0.71073 Å ( R( F)=0.0686 for 29,053 reflections). Data were collected on a Bruker Smart Apex CCD diffractometer at 293 K in the range of 1.76< θ<28.06° using ω-2 θ scans technique. The structure of the title compound may be considered to be based on {Mo 6O 12(HPO 4) 3(PO 4)(OH) 3} units bonded together with {Mn(phen) 2} subunits into a two-dimensional network. Two types of tunnels are observed in the solid of the title compound.

  13. Werner coordination chemistry and neurodegeneration.

    Science.gov (United States)

    Telpoukhovskaia, Maria A; Orvig, Chris

    2013-02-21

    Neurodegenerative diseases are capturing the world's attention as being the next set of diseases we must tackle collectively. Not only are the patients experiencing gradual cognitive and physical decline in most cases, but these diseases are fatal with no prevention currently available. As these diseases are progressive, providing care and symptom treatment for the ageing population is becoming both a medical and a financial challenge. This review discusses how Werner coordination chemistry plays a role in three diseases - those of Alzheimer's, Parkinson's, and prions. Metal ions are considered to be involved in these diseases in part via their propensity to cause toxic aggregation of proteins. First, the coordination of metal ions, with emphasis on copper(II), to metalloproteins that are hallmarks of these diseases - amyloid β, α-synuclein, and prion, respectively - will be discussed. We will present the current understanding of the metal coordination environments created by the amino acids of these proteins, as well as metal binding affinity. Second, a diverse set of examples of rationally designed metal chelators to outcompete this deleterious binding will be examined based on coordination mode and affinity toward bio-relevant metal ions. Overall, this review will give a general overview of protein and metal chelator coordination environments in neurodegenerative diseases.

  14. Intelligent multiagent coordination based on reinforcement hierarchical neuro-fuzzy models.

    Science.gov (United States)

    Mendoza, Leonardo Forero; Vellasco, Marley; Figueiredo, Karla

    2014-12-01

    This paper presents the research and development of two hybrid neuro-fuzzy models for the hierarchical coordination of multiple intelligent agents. The main objective of the models is to have multiple agents interact intelligently with each other in complex systems. We developed two new models of coordination for intelligent multiagent systems, which integrates the Reinforcement Learning Hierarchical Neuro-Fuzzy model with two proposed coordination mechanisms: the MultiAgent Reinforcement Learning Hierarchical Neuro-Fuzzy with a market-driven coordination mechanism (MA-RL-HNFP-MD) and the MultiAgent Reinforcement Learning Hierarchical Neuro-Fuzzy with graph coordination (MA-RL-HNFP-CG). In order to evaluate the proposed models and verify the contribution of the proposed coordination mechanisms, two multiagent benchmark applications were developed: the pursuit game and the robot soccer simulation. The results obtained demonstrated that the proposed coordination mechanisms greatly improve the performance of the multiagent system when compared with other strategies.

  15. Coordination of plant mitochondrial biogenesis: keeping pace with cellular requirements.

    Directory of Open Access Journals (Sweden)

    Elina eWelchen

    2014-01-01

    Full Text Available Plant mitochondria are complex organelles that carry out numerous metabolic processes related with the generation of energy for cellular functions and the synthesis and degradation of several compounds. Mitochondria are semiautonomous and dynamic organelles changing in shape, number and composition depending on tissue or developmental stage. The biogenesis of functional mitochondria requires the coordination of genes present both in the nucleus and the organelle. In addition, due to their central role, all processes held inside mitochondria must be finely coordinated with those in other organelles according to cellular demands. Coordination is achieved by transcriptional control of nuclear genes encoding mitochondrial proteins by specific transcription factors that recognize conserved elements in their promoter regions. In turn, the expression of most of these transcription factors is linked to developmental and environmental cues, according to the availability of nutrients, light-dark cycles and warning signals generated in response to stress conditions. Among the signals impacting in the expression of nuclear genes, retrograde signals that originate inside mitochondria help to adjust mitochondrial biogenesis to organelle demands. Adding more complexity, several nuclear encoded proteins are dual localized to mitochondria and either chloroplasts or the nucleus. Dual targeting might establish a crosstalk between the nucleus and cell organelles to ensure a fine coordination of cellular activities. In this article, we discuss how the different levels of coordination of mitochondrial biogenesis interconnect to optimize the function of the organelle according to both internal and external demands.

  16. Coordination of plant mitochondrial biogenesis: keeping pace with cellular requirements

    Science.gov (United States)

    Welchen, Elina; García, Lucila; Mansilla, Natanael; Gonzalez, Daniel H.

    2014-01-01

    Plant mitochondria are complex organelles that carry out numerous metabolic processes related with the generation of energy for cellular functions and the synthesis and degradation of several compounds. Mitochondria are semiautonomous and dynamic organelles changing in shape, number, and composition depending on tissue or developmental stage. The biogenesis of functional mitochondria requires the coordination of genes present both in the nucleus and the organelle. In addition, due to their central role, all processes held inside mitochondria must be finely coordinated with those in other organelles according to cellular demands. Coordination is achieved by transcriptional control of nuclear genes encoding mitochondrial proteins by specific transcription factors that recognize conserved elements in their promoter regions. In turn, the expression of most of these transcription factors is linked to developmental and environmental cues, according to the availability of nutrients, light–dark cycles, and warning signals generated in response to stress conditions. Among the signals impacting in the expression of nuclear genes, retrograde signals that originate inside mitochondria help to adjust mitochondrial biogenesis to organelle demands. Adding more complexity, several nuclear encoded proteins are dual localized to mitochondria and either chloroplasts or the nucleus. Dual targeting might establish a crosstalk between the nucleus and cell organelles to ensure a fine coordination of cellular activities. In this article, we discuss how the different levels of coordination of mitochondrial biogenesis interconnect to optimize the function of the organelle according to both internal and external demands. PMID:24409193

  17. Coordination in fast repetitive violin-bowing patterns.

    Science.gov (United States)

    Schoonderwaldt, Erwin; Altenmüller, Eckart

    2014-01-01

    We present a study of coordination behavior in complex violin-bowing patterns involving simultaneous bow changes (reversal of bowing direction) and string crossings (changing from one string to another). Twenty-two violinists (8 advanced amateurs, 8 students with violin as major subject, and 6 elite professionals) participated in the experiment. We investigated the influence of a variety of performance conditions (specific bowing patterns, dynamic level, tempo, and transposition) and level of expertise on coordination behavior (a.o., relative phase and amplitude) and stability. It was found that the general coordination behavior was highly consistent, characterized by a systematic phase lead of bow inclination over bow velocity of about 15° (i.e., string crossings were consistently timed earlier than bow changes). Within similar conditions, a high individual consistency was found, whereas the inter-individual agreement was considerably less. Furthermore, systematic influences of performance conditions on coordination behavior and stability were found, which could be partly explained in terms of particular performance constraints. Concerning level of expertise, only subtle differences were found, the student and professional groups (higher level of expertise) showing a slightly higher stability than the amateur group (lower level of expertise). The general coordination behavior as observed in the current study showed a high agreement with perceptual preferences reported in an earlier study to similar bowing patterns, implying that complex bowing trajectories for an important part emerge from auditory-motor interaction.

  18. Coordination in fast repetitive violin-bowing patterns.

    Directory of Open Access Journals (Sweden)

    Erwin Schoonderwaldt

    Full Text Available We present a study of coordination behavior in complex violin-bowing patterns involving simultaneous bow changes (reversal of bowing direction and string crossings (changing from one string to another. Twenty-two violinists (8 advanced amateurs, 8 students with violin as major subject, and 6 elite professionals participated in the experiment. We investigated the influence of a variety of performance conditions (specific bowing patterns, dynamic level, tempo, and transposition and level of expertise on coordination behavior (a.o., relative phase and amplitude and stability. It was found that the general coordination behavior was highly consistent, characterized by a systematic phase lead of bow inclination over bow velocity of about 15° (i.e., string crossings were consistently timed earlier than bow changes. Within similar conditions, a high individual consistency was found, whereas the inter-individual agreement was considerably less. Furthermore, systematic influences of performance conditions on coordination behavior and stability were found, which could be partly explained in terms of particular performance constraints. Concerning level of expertise, only subtle differences were found, the student and professional groups (higher level of expertise showing a slightly higher stability than the amateur group (lower level of expertise. The general coordination behavior as observed in the current study showed a high agreement with perceptual preferences reported in an earlier study to similar bowing patterns, implying that complex bowing trajectories for an important part emerge from auditory-motor interaction.

  19. Federal interagency radiation policy coordination

    International Nuclear Information System (INIS)

    Young, A.L.

    1984-01-01

    The author discusses Federal interagency radiation policy coordination. The Committee on Interagency Radiation Research and Policy Coordination (CIRRPC) is explained as being dedicated to the success and forward motion of enhanced radiation research and policy coordination. Both CIRRPC and the Science Panel are staffed with Federal employees. Their expertise includes many and various radiation disciplines including cytogenetics, dosimetry, epidemiology, genetics, health physics, nuclear medicine, radiology, radiation carcinogenesis, and risk assessment. Ten scientific and technical issues in their preliminary order are presented: radioepidemiological tables; de minimis radiation levels; radon progeny health effects; occupational exposure registry; measurement, recording, and control of radiation; food irradiation; use of radiation in science, industry, and medicine; nonionizing radiation; and remedial actions

  20. An argument for VP coordination: scene-setting coordination and ...

    African Journals Online (AJOL)

    This article demonstrates the properties of this curious construction type and proposes the first analysis to date. It is argued that this is an instance of VP coordination and that this configuration allows the possibility of high merger of direct objects in a constrained fashion. Southern African Linguistics and Applied Language ...

  1. Implicit Coordination Strategies for Effective Team Communication.

    Science.gov (United States)

    Butchibabu, Abhizna; Sparano-Huiban, Christopher; Sonenberg, Liz; Shah, Julie

    2016-06-01

    We investigated implicit communication strategies for anticipatory information sharing during team performance of tasks with varying degrees of complexity. We compared the strategies used by teams with the highest level of performance to those used by the lowest-performing teams to evaluate the frequency and methods of communications used as a function of task structure. High-performing teams share information by anticipating the needs of their teammates rather than explicitly requesting the exchange of information. As the complexity of a task increases to involve more interdependence among teammates, the impact of coordination on team performance also increases. This observation motivated us to conduct a study of anticipatory information sharing as a function of task complexity. We conducted an experiment in which 13 teams of four people performed collaborative search-and-deliver tasks with varying degrees of complexity in a simulation environment. We elaborated upon prior characterizations of communication as implicit versus explicit by dividing implicit communication into two subtypes: (a) deliberative/goal information and (b) reactive status updates. We then characterized relationships between task structure, implicit communication, and team performance. We found that the five teams with the fastest task completion times and lowest idle times exhibited higher rates of deliberative communication versus reactive communication during high-complexity tasks compared with the five teams with the slowest completion times and longest idle times (p = .039). Teams in which members proactively communicated information about their next goal to teammates exhibited improved team performance. The findings from our work can inform the design of communication strategies for team training to improve performance of complex tasks. © 2016, Human Factors and Ergonomics Society.

  2. A coordination language for databases

    DEFF Research Database (Denmark)

    Li, Ximeng; Wu, Xi; Lluch Lafuente, Alberto

    2017-01-01

    We present a coordination language for the modeling of distributed database applications. The language, baptized Klaim-DB, borrows the concepts of localities and nets of the coordination language Klaim but re-incarnates the tuple spaces of Klaim as databases. It provides high-level abstractions...... in the semantics. The use of the language is illustrated in a scenario where the sales from different branches of a chain of department stores are aggregated from their local databases. Raising the abstraction level and encapsulating integrity checks in the language primitives have benefited the modeling task...

  3. Coordination Processes in International Organisations

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    2008-01-01

    -à-vis their principals, the Member States. The Commission is the leading agent in the phase leading up to the Conference; the Presidency then takes over. On the one hand, due to the Treaty obligations and their interpretations by the Court of Justice, both the Presidency and the Commission are kept within tight limits...... by the principals. On the other hand, both before and during the Conference, the Member States accept the so-called discursive coordination of the Commission, which seems to be of great (but often neglected) importance. Owing to the organisational set-up in which coordination takes place, the EU is able...

  4. Spectral studies of coordination compounds of cobalt(II) with thiosemicarbazone of heterocyclic ketone

    Science.gov (United States)

    Chandra, Sulekh; Kumar, Umendra

    2005-12-01

    The paper presents the spectral analysis of cobalt(II) complexes with indoxyl thiosemicarbazone (ITSC) of general composition [CoL 2X 2] (where L = ITSC, X = Cl -, NO 3-, (1/2)SO 42-, NCS -). The geometry of the complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibility measurements and spectral (electronic, IR, EPR, 1H NMR, mass) studies. The various physico-chemical techniques suggested a coordination number of six (octahedral) for chloro, nitrato and thiocyanato complexes. Whereas sulfato complex was found to have five coordinate trigonal-bipyramidal geometry. All the complexes are of high spin type showing magnetic moment corresponding to three unpaired electrons.

  5. The Convex Coordinates of the Symmedian Point

    Science.gov (United States)

    Boyd, J. N.; Raychowdhury, P. N.

    2006-01-01

    In this note, we recall the convex (or barycentric) coordinates of the points of a closed triangular region. We relate the convex and trilinear coordinates of the interior points of the triangular region. We use the relationship between convex and trilinear coordinates to calculate the convex coordinates of the symmedian point of the triangular…

  6. Coordination in networks for improved mental health service

    Directory of Open Access Journals (Sweden)

    Johan Hansson

    2010-08-01

    Full Text Available Background: Well-organised clinical cooperation between health and social services has been difficult to achieve in Sweden as in other countries. Purpose: This paper presents an empirical study of a mental health coordination network in one area in Stockholm. The aim was to describe the development and nature of coordination within a mental health and social care consortium and to assess the impact on care processes and client outcomes. Method: Data was gathered through interviews with coordina­tors from three rehabilitation units. The interviews focused on coordination activities aimed at supporting the clients’ needs and investigated how the coordinators acted according to the consortium's holistic approach. Data on The Camberwell Assess­ment of Need (CAN-S showing clients’ satisfaction was used to assess on set of outcomes. Findings: The findings revealed different coordination activities and factors both helping and hindering the network coordination activities. One factor helping was the history of local and personal informal cooperation and shared responsibilities evident. Unclear roles and routines hindered cooperation Practical value: The contribution is an empirical example and a model for organisations establishing structures for network coordination. One lesson for current policy about integrated health care is to adapt and implement ”pair coordinators” where full structural integration is not possible. Another lesson, based on the idea of patient quality by coordinated care, is specific to adapt the work of the local psychiatric addictive team – an independent special team in the psychiatric outpatient care serving psychotic clients with complex addictive problems.

  7. Coordination in networks for improved mental health service

    Directory of Open Access Journals (Sweden)

    Johan Hansson

    2010-08-01

    Full Text Available Background: Well-organised clinical cooperation between health and social services has been difficult to achieve in Sweden as in other countries.Purpose: This paper presents an empirical study of a mental health coordination network in one area in Stockholm. The aim was to describe the development and nature of coordination within a mental health and social care consortium and to assess the impact on care processes and client outcomes.Method: Data was gathered through interviews with coordina­tors from three rehabilitation units. The interviews focused on coordination activities aimed at supporting the clients’ needs and investigated how the coordinators acted according to the consortium's holistic approach. Data on The Camberwell Assess­ment of Need (CAN-S showing clients’ satisfaction was used to assess on set of outcomes. Findings: The findings revealed different coordination activities and factors both helping and hindering the network coordination activities. One factor helping was the history of local and personal informal cooperation and shared responsibilities evident. Unclear roles and routines hindered cooperationPractical value: The contribution is an empirical example and a model for organisations establishing structures for network coordination. One lesson for current policy about integrated health care is to adapt and implement ”pair coordinators” where full structural integration is not possible. Another lesson, based on the idea of patient quality by coordinated care, is specific to adapt the work of the local psychiatric addictive team – an independent special team in the psychiatric outpatient care serving psychotic clients with complex addictive problems.

  8. The Open Method of Coordination and the Implementation of the Bologna Process

    Science.gov (United States)

    Veiga, Amelia; Amaral, Alberto

    2006-01-01

    In this paper the authors argue that the use of the Open Method of Coordination (OMC) in the implementation of the Bologna process presents coordination problems that do not allow for the full coherence of the results. As the process is quite complex, involving three different levels (European, national and local) and as the final actors in the…

  9. Haptic feedback helps bipedal coordination

    NARCIS (Netherlands)

    Roelofsen, E.G.J.; Bosga, J.; Rosenbaum, D.A.; Nijhuis-Van der Sanden, M.W.G.; Hullegie, W.A.M.; Cingel, R.E. van; Meulenbroek, R.G.J.

    2016-01-01

    The present study investigated whether special haptic or visual feedback would facilitate the coordination of in-phase, cyclical feet movements of different amplitudes. Seventeen healthy participants sat with their feet on sliding panels that were moved externally over the same or different

  10. Collective coordinates on symplectic manifolds

    International Nuclear Information System (INIS)

    Razumov, A.V.; Taranov, A.Yu.

    1981-01-01

    For an arbitrary Lie group of canonical transformations on a symplectic manifold collective coordinates are introduced. They describe a motion of the dynamical system as a whole under the group transformations. Some properties of Lie group of canonical transformations are considered [ru

  11. Archimedes' Principle in General Coordinates

    Science.gov (United States)

    Ridgely, Charles T.

    2010-01-01

    Archimedes' principle is well known to state that a body submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body. Herein, Archimedes' principle is derived from first principles by using conservation of the stress-energy-momentum tensor in general coordinates. The resulting expression for the force is…

  12. Reversibility in dynamic coordination problems

    Czech Academy of Sciences Publication Activity Database

    Kováč, Eugen; Steiner, Jakub

    -, č. 374 (2008), s. 1-50 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : dynamic coordination problems * global games * Laplacian belief Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp374.pdf

  13. Co-ordinated Classroom Lectures.

    Science.gov (United States)

    Harmon, Darell Boyd

    From a series of lectures, a selection of eight are oriented principally toward the biologically developing child, and the physiological operations in visual process. The numbered lectures are--(1) The Coordinated Classroom, its Philosophy and Principles, (2) An Outline of a Biological Point of View, (3) The Evolution of Structure--despite man's…

  14. Motivic amplitudes and cluster coordinates

    International Nuclear Information System (INIS)

    Golden, J.K.; Goncharov, A.B.; Spradlin, M.; Vergu, C.; Volovich, A.

    2014-01-01

    In this paper we study motivic amplitudes — objects which contain all of the essential mathematical content of scattering amplitudes in planar SYM theory in a completely canonical way, free from the ambiguities inherent in any attempt to choose particular functional representatives. We find that the cluster structure on the kinematic configuration space Conf n (ℙ 3 ) underlies the structure of motivic amplitudes. Specifically, we compute explicitly the coproduct of the two-loop seven-particle MHV motivic amplitude A 7,2 M and find that like the previously known six-particle amplitude, it depends only on certain preferred coordinates known in the mathematics literature as cluster X-coordinates on Conf n (ℙ 3 ). We also find intriguing relations between motivic amplitudes and the geometry of generalized associahedrons, to which cluster coordinates have a natural combinatoric connection. For example, the obstruction to A 7,2 M being expressible in terms of classical polylogarithms is most naturally represented by certain quadrilateral faces of the appropriate associahedron. We also find and prove the first known functional equation for the trilogarithm in which all 40 arguments are cluster X-coordinates of a single algebra. In this respect it is similar to Abel’s 5-term dilogarithm identity

  15. On the Principle of Coordination

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten)

    2001-01-01

    textabstractOn many occasions, individuals are able to coordinate their actions. The first empirical evidence to this effect has been described by Schelling (1960) in an informal experiment. His results were corroborated many years later by Mehta et al. (1994a,b) and Bacharach and Bernasconi (1997).

  16. Coordination in a mobile world

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    -, č. 295 (2006), s. 1-35 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : coordination * equilibrium uniqueness * global games Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp295.pdf

  17. Coordinated Home Care Training Manual.

    Science.gov (United States)

    Michigan Univ., Ann Arbor. Home Care Training Center.

    This manual is intended as a source of information and assistance in the planning, organization, implementation, and evaluation of home care programs. There are ten major sections: (1) Introduction (review of the history of home care and definition of pertinent terms), (2) Program Planning, (3) Organizational Structure, (4) Coordination and…

  18. Synchronous coordination of distributed omponents

    NARCIS (Netherlands)

    Proença, José

    2011-01-01

    This work contributes to the field of coordination, in particular to Reo, by improving existing approaches to execute synchronisation models in three major ways. First, this work supports decoupled execution and lightweight reconfiguration. We developed a prototype Dreams engine to test our

  19. Metal complexes of phosphinic acids

    International Nuclear Information System (INIS)

    Das, P.N.M.; Kuchen, W.; Keck, H.; Haegele, G.

    1977-01-01

    Pr(III), Nd(III) and Eu(III) complexes of dimethyldithiophosphinic acid have been prepared. Their properties and structures have been studied using elemental analysis, molecular weight determination, IR, UV, mass, NMR, magnetic studies, etc. It is found that these metals form neutral complexes of the type ML 3 where L is a deprotonated bidentate dimethyldithiophosphinic acid molecule. The coordination number exhibited by these metals in this case is six. Octahedral structures have been assigned to these complexes. (author)

  20. Bis-phosphine allene ligand: coordination chemistry and preliminary applications in catalysis.

    Science.gov (United States)

    Vanitcha, Avassaya; Damelincourt, Cecilia; Gontard, Geoffrey; Vanthuyne, Nicolas; Mouriès-Mansuy, Virginie; Fensterbank, Louis

    2016-05-21

    A 1,3-bis-diphenylphosphine allene can give rise to new coordination complexes with palladium, platinum and gold metals. These complexes were fully characterized by NMR, HRMS and X-ray diffraction analysis. For gold(i), the corresponding dinuclear complex has been used in a series of diagnostic catalytic reactions and gave promising preliminary results in asymmetric catalysis.