Distribution by Scientific Domains
Distribution within Chemistry

Kinds of H2O

  • cm h2o

  • Terms modified by H2O

  • h2o ligand
  • h2o molecule
  • h2o system

  • Selected Abstracts

    A role for the volume regulated anion channel in volume regulation in the murine CNS cell line, CAD

    ACTA PHYSIOLOGICA, Issue 2 2010
    V. L. Harvey
    Abstract Aim:, The role of the volume regulated anion channel (VRAC) in a model CNS neuronal cell line, CAD, was investigated. Methods:, Changes in cell volume following hypotonic challenges were measured using a video-imaging technique. The effect of the Cl, channel antagonists tamoxifen (10 ,m) and 4,4,-diisothiocyanatostilbene-2,2,-disulphonic acid (DIDS; 100 ,m) on regulatory volume decrease (RVD) were measured. The whole-cell voltage-clamp technique was used to characterize IClswell, the current underlying the VRAC. Results:, Using the video-imaging technique, CAD cells were found to swell and subsequently exhibit RVD when subjected to a sustained hypotonic challenge from 300 mOsmol kg,1 H2O to 210 mOsmol kg,1 H2O. In the presence of tamoxifen (10 ,m) or DIDS (100 ,m) RVD was abolished, suggesting a role for the VRAC. A hypotonic solution (230 mOsmol kg,1 H2O) evoked IClswell, an outwardly rectifying current displaying time-independent activation, which reversed upon return to isotonic conditions. The reversal potential (Erev) for IClswell was ,14.7 1.4 mV, similar to the theoretical Erev for a selective Cl, conductance. IClswell was inhibited in the presence of DIDS (100 ,m) and tamoxifen (10 ,m), the DIDS inhibition being voltage dependent. Conclusions:, Osmotic swelling elicits an outwardly rectifying Cl, conductance in CAD cells. The IClswell observed in these cells is similar to that observed in other cells, and is likely to provide a pathway for the loss of Cl, which leads to water loss and RVD. As ischaemia, brain trauma, hypoxia and other brain pathologies can cause cell swelling, CAD cells represent a model cell line for the study of neuronal cell volume regulation. [source]

    Transformation of a zinc inclusion complex to wurtzite ZnS microflowers under solvothermal conditions

    Liwei Mi
    Abstract Wurtzite zinc sulfide (ZnS) microflowers were synthesized successfully by a convenient solvothermal route in ethylene glycol (EG) and ethylenediamine (EN) using thiourea and zinc inclusion complex as starting materials. The inclusion complex {[Zn(bipy)2(H2O)2](4-Cl-3-NH2 -C6H3SO3)2(bipy) (H2O)2}n was achieved by the reaction of zinc oxide (ZnO) and 4-Cl-3-NH2 -C6H3SO3 with the bridging ligand bipy under moderate conditions, in which bipy is 4,4,-bipyridine and 4-Cl-3-NH2C6H3SO3NH is 4-Chloro-3-aminobenzene sulfonic acid. The phase purity of bulk products was confirmed by powder X-ray diffraction and element analysis. The factors that might affect the purity of the ZnS product during the synthesis were discussed in detail. It was found that the products were significantly affected by the mixed solvents and the starting materials. X-ray single crystal diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) were used to characterize the products. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis, structure and photoluminescence of a 3D pillared heterometallic coordination polymer containing 2D inorganic cadmium-potassium-oxide layer subunits

    Qing-Yan Liu
    Abstract Self-assembly of Cd(NO3)2 with o -phthalic acid monopotassium salt (KHphth) in the presence of ethylenediamine (en) produced a new heterometallic coordination polymer [CdK2(phth)2(en)0.5(H2O)]n (1). Single-crystal X-ray analyses reveal that it crystallizes in a monoclinic space group P 21/c. a = 11.6707(6) , b = 8.1019(4) , c = 20.9503(11) , , = 94.6640(10)o. The complex displays an en-pillared 3D framework, which is constructed from 2D [CdK2(phth)2(H2O)]n layers featuring uncommon inorganic cadmium-potassium-oxide layers containing potassium-oxide layers. In the solid state, complex 1 shows photoluminescence with the maximum emission intensities at 355 nm upon excitation at 312 nm. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Imidazolium based ionic liquid crystals: structure, photophysical and thermal behaviour of [Cnmim]BrxH2O (n = 12, 14; x=0, 1)

    A. Getsis
    Abstract The long chain imidazolium halides [Cnmim]BrxH2O (n = 10, 12; x = 0, 1) have been synthesized and their structural and thermal behaviour together with their photophysical properties characterized. X-ray structure analyses of the monohydrates ([C12mim]BrH2O: triclinic, P1, no. 2, Z = 2, Pearson code aP112, a = 550.0(5) pm, b = 779.4(5) pm, c = 2296.1(5) pm, , = 81.89(5), , = 83.76(5), , = 78.102(5), 3523 unique reflections with Io > 2,(Io), R1 = 0.0263, wR2 = 0.0652, GooF = 1.037, T = 263(2) K; [C14mim]Br,H2O: triclinic, P1, no. 2, Z = 12, Pearson code aP11, a = 549.86(8) pm, 782.09(13) pm, c = 2511.3(4) pm, , = 94.86(2), , = 94.39(2), , = 101.83(2), 2063 unique reflections with Io > 2,(Io), R1 = 0.0429, wR2 = 0.0690, GooF = 0.770, T = 293(2) K) show for both compounds similar bilayered structures. Sheets composed of hydrophilic structure regions constituted by positively charged imidazolium head groups, bromide anions and hydrogen bonded water alternate with hydrophobic areas formed by interdigitated long alkyl chains belonging to imidazolium cations with different orientation. Combined differential scanning calorimetry and polarizing optical microscopy shows that the monohydrates as well as the anhydrous imidazolium salts are thermotropic liquid crystals which adopt smectic mesophases. The mesophase region is larger in case of the monohydrates when compared to the anhydrous compounds indicating that water obviously stabilizes the mesophase. All compounds show an intense whitish photoluminescence with short lived (1,,1,*) and long lived (1,,3,*) transitions. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis, crystal structure and vibrational characterization of bis-,-peroxo-hexacarbonatodicerate(IV) complexes of rubidium and cesium

    N.-P. Pook
    Abstract The new compounds Rb8[Ce(O2)(CO3)3]2 12 H2O (1) and Cs8[Ce(O2)(CO3)3]2 10 H2O (2) were obtained from the reaction of hydrogen peroxide and Ce(III) in saturated alkali carbonate solutions. The crystal structures and the unit cell parameters of (1) triclinic, P-1 with a = 8.973(2) , b = 10.815(2) , c = 11.130(3) , , = 66.992(2), , = 68.337(2), , = 74.639(2), VEZ = 914.7(4) 3, Z = 2, and (2) orthorhombic, Pbca, a = 19.3840(16) , b = 18.528(2) , c = 10.487(3) , VEZ = 3766.4(13) 3, Z = 8, were determined. Both compounds contain the bis--peroxo-hexacarbonatodicerate(IV)-ion, [(CO3)3Ce(O2)2Ce(CO3)3]8- . IR and Raman spectra were measured and discussed. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis and crystal strcucture of two zinc inclusion complexes

    Min-Le Han
    Abstract X-ray single crystals of these two inclusion complexes, [Zn(H2O)4L2](4-amino-1-naphthalene sulfonate)2 (L = 1,3-bis(4-pyridyl) propane), 1, and [Zn(H2O)(bipy)2](4-amino-1-naphthalene sulfonate)(NO3) (bipy = 4,4'-bipyridine), 2 were achieved by the reaction of Zn(NO3)2 and 4-amino-1-naphthalene sulfonate to 1,3-bis(4-pyridyl) propane and 4,4'-bipyridine, respectively. As inclusion complexes, the cationic components of 1 and 2 were formed by two infinite zigzag chains, while, 4-amino-1-naphthalene sulfonate made up the anionic parts of these two complexes. Thus, the whole molecules of these two complexes are neuter. Numous hydrogen bonds could be found in these two inclusion complexes, which help them to form three-dimensional solid-state packing structure architectures. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Crystal growth and magnetic properties of the copper coordination polymer [Cu( -C2O4)(4-aminopyridine)2(H2O)]n

    A. V. Prokofiev
    Abstract In this paper, we consider various ways of crystal growth of the polymer [Cu( -C2O4)(4-aminopyridine)2(H2O)]n. Single crystals of the size of mm3 have been grown by a slow diffusion technique from solutions of the monoammine copper complex and of the mixture of potassium oxalate and aminopyridine with the stoichiometric ratio. Magnetic susceptibility and ESR measurements have been performed on single crystals large enough for investigating anisotropic properties. The susceptibility can be well described within the model of a Heisenberg antiferromagnetic spin chain. The magnetic measurements reveal a small concentration of paramagnetic moments reflecting the high quality of the single crystals. ( 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis and crystal structure of [CuCl(phen)2]3H3V10O28 7 H2O

    E. Rakovsk
    Abstract The new compound, [CuCl(phen)2]3H3V10O28 7 H2O, was prepared by reaction of an aqueous KVO3 solution (pH 3) with an aqueous solution of CuSO4 5 H2O in which 1,10-phenanthroline (phen) and KCl were added. The crystal structure of the compound was determined, and the proton position in H3V10O283, were calculated by the bond length/bond number method and also determined from difference electron density map. The protons are bound to colinearly arranged ,,OV2 and ,,OV3 groups which is the common protonation type in trihydrogen decavanadates. The structure crystallizes in P1 space group symmetry. ( 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Ca for Er substitution in tetragonal ErPO4 H2O crystallised from phosphoric acid solution

    R. Kijkowska
    Abstract Erbium phosphate monohydrate with limited Ca for Er substitution, obtained through crystallisation from boiling phosphoric acid solution has been characterised by X-ray diffraction, Ir-spectroscopy and thermal analysis (TGA-DTA) methods. The difference in the electric charge between di-valent calcium and tri-valent erbium in the solid crystallised was compensated by simultaneous substitution of HPO42- for PO43- . Ca incorporation in erbium phosphate made expansion of tetragonal ErPO4 H2O unit cell. After ignition at 900 C the tetragonal crystal modification was maintained but the unit cell parameters of all the investigated phosphates, whether Ca-substituted or Ca-free, contracted to the same level. The unique contraction of the unit cell was resulted from recrystallisation of Ca-substituted into Ca-free erbium phosphate, while Ca was transferred into Ca(PO3)2 formed as a separate phase. ( 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    A Single Ventilator for Multiple Simulated Patients to Meet Disaster Surge

    Greg Neyman MD
    Objectives To determine if a ventilator available in an emergency department could quickly be modified to provide ventilation for four adults simultaneously. Methods Using lung simulators, readily available plastic tubing, and ventilators (840 Series Ventilator; Puritan-Bennett), human lung simulators were added in parallel until the ventilator was ventilating the equivalent of four adults. Data collected included peak pressure, positive end-expiratory pressure, total tidal volume, and total minute ventilation. Any obvious asymmetry in the delivery of gas to the lung simulators was also documented. The ventilator was run for almost 12 consecutive hours (5.5 hours of pressure control and more than six hours of volume control). Results Using readily available plastic tubing set up to minimize dead space volume, the four lung simulators were easily ventilated for 12 hours using one ventilator. In pressure control (set at 25 mm H2O), the mean tidal volume was 1,884 mL (approximately 471 mL/lung simulator) with an average minute ventilation of 30.2 L/min (or 7.5 L/min/lung simulator). In volume control (set at 2 L), the mean peak pressure was 28 cm H2O and the minute ventilation was 32.5 L/min total (8.1 L/min/lung simulator). Conclusions A single ventilator may be quickly modified to ventilate four simulated adults for a limited time. The volumes delivered in this simulation should be able to sustain four 70-kg individuals. While further study is necessary, this pilot study suggests significant potential for the expanded use of a single ventilator during cases of disaster surge involving multiple casualties with respiratory failure. [source]

    Abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea communities of an alkaline sandy loam

    Ju-pei Shen
    Summary The abundance and composition of soil ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities under different long-term (17 years) fertilization practices were investigated using real-time polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE). A sandy loam with pH (H2O) ranging from 8.3 to 8.7 was sampled in years 2006 and 2007, including seven fertilization treatments of control without fertilizers (CK), those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): NP, NK, PK and NPK, half chemical fertilizers NPK plus half organic manure (1/2OMN) and organic manure (OM). The highest bacterial amoA gene copy numbers were found in those treatments receiving N fertilizer. The archaeal amoA gene copy numbers ranging from 1.54 107 to 4.25 107 per gram of dry soil were significantly higher than those of bacterial amoA genes, ranging from 1.24 105 to 2.79 106 per gram of dry soil, which indicated a potential role of AOA in nitrification. Ammonia-oxidizing bacteria abundance had significant correlations with soil pH and potential nitrification rates. Denaturing gradient gel electrophoresis patterns revealed that the fertilization resulted in an obvious change of the AOB community, while no significant change of the AOA community was observed among different treatments. Phylogenetic analysis showed a dominance of Nitrosospira -like sequences, while three bands were affiliated with the Nitrosomonas genus. All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin). These results suggest that long-term fertilization had a significant impact on AOB abundance and composition, while minimal on AOA in the alkaline soil. [source]

    Quantitative analyses of the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea of a Chinese upland red soil under long-term fertilization practices

    Ji-zheng He
    Summary The abundance and composition of soil ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were investigated by using quantitative real-time polymerase chain reaction, cloning and sequencing approaches based on amoA genes. The soil, classified as agri-udic ferrosols with pH (H2O) ranging from 3.7 to 6.0, was sampled in summer and winter from long-term field experimental plots which had received 16 years continuous fertilization treatments, including fallow (CK0), control without fertilizers (CK) and those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): N, NP, NK, PK, NPK and NPK plus organic manure (OM). Population sizes of AOB and AOA changed greatly in response to the different fertilization treatments. The NPK + OM treatment had the highest copy numbers of AOB and AOA amoA genes among the treatments that received mineral fertilizers, whereas the lowest copy numbers were recorded in the N treatment. Ammonia-oxidizing archaea were more abundant than AOB in all the corresponding treatments, with AOA to AOB ratios ranging from 1.02 to 12.36. Significant positive correlations were observed among the population sizes of AOB and AOA, soil pH and potential nitrification rates, indicating that both AOB and AOA played an important role in ammonia oxidation in the soil. Phylogenetic analyses of the amoA gene fragments showed that all AOB sequences from different treatments were affiliated with Nitrosospira or Nitrosospira- like species and grouped into cluster 3, and little difference in AOB community composition was recorded among different treatments. All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin). Cluster M dominated exclusively in the N, NP, NK and PK treatments, indicating a pronounced difference in the community composition of AOA in response to the long-term fertilization treatments. These findings could be fundamental to improve our understanding of the importance of both AOB and AOA in the cycling of nitrogen and other nutrients in terrestrial ecosystems. [source]

    A novel reactor for exploring the effect of water content on biofilter degradation rates

    Milinda A. Ranasinghe
    A novel batch recycle reactor was developed to investigate the effect of water content changes on the biological degradation rate of gas phase contaminants in low water content systems, such as biofilters. The reactor tightly controlled the water content of the unsaturated packing material using the principle of a suction cell. Matric potential in the compost was controlled between ,6 and ,36 cm H2O. A soil water retention curve relating matric potential to gravimetric water content was generated for the compost. Periodic dry weight analyses of reactor samples, together with the water retention curve, verified moisture content control. Runs were performed with toluene as the contaminant using unamended compost at a constant temperature of 30C. Degradation results indicated a linear, biologically limited degradation region, followed by a non-linear region at lower concentrations. Elimination capacities were calculated for the linear region for different matric potentials along both the wetting and drying curves, and both changes in the water content and direction of approach affected the removal rates in the linear region. The elimination capacity ranged from 155 g/m3 hr to 24 g/m3 hr for toluene over the matric potential range investigated. Repeatability studies indicated that moisture content was most likely the parameter that influenced changes in performance. [source]

    Brain Blood-flow Alterations Induced by Therapeutic Vagus Nerve Stimulation in Partial Epilepsy: II.

    EPILEPSIA, Issue 9 2004
    Low Levels of Stimulation, Prolonged Effects at High
    Summary:,Purpose: To measure vagus nerve stimulation (VNS)-induced cerebral blood flow (CBF) effects after prolonged VNS and to compare these effects with immediate VNS effects on CBF. Methods: Ten consenting partial epilepsy patients had positron emission tomography (PET) with intravenous [15O]H2O. Each had three control scans without VNS and three scans during 30 s of VNS, within 20 h after VNS began (immediate-effect study), and repeated after 3 months of VNS (prolonged study). After intrasubject subtraction of control from stimulation scans, images were anatomically transformed for intersubject averaging and superimposed on magnetic resonance imaging (MRI) for anatomic localization. Changes on t-statistical maps were considered significant at p < 0.05 (corrected for multiple comparisons). Results: During prolonged studies, CBF changes were not observed in any regions that did not have CBF changes during immediate-effect studies. During both types of studies, VNS-induced CBF increases were similarly located in the bilateral thalami, hypothalami, inferior cerebellar hemispheres, and right postcentral gyrus. During immediate-effect studies, VNS decreased bilateral hippocampal, amygdalar, and cingulate CBF and increased bilateral insular CBF; no significant CBF changes were observed in these regions during prolonged studies. Mean seizure frequency decreased by 25% over a 3-month period between immediate and prolonged PET studies, compared with 3 months before VNS began. Conclusions: Seizure control improved during a period over which some immediate VNS-induced CBF changes declined (mainly over cortical regions), whereas other VNS-induced CBF changes persisted (mainly over subcortical regions). Altered synaptic activities at sites of persisting VNS-induced CBF changes may reflect antiseizure actions. [source]

    C5a anaphylatoxin as a product of complement activation up-regulates the complement inhibitory factor H in rat Kupffer cells

    Gerald Schlaf
    Abstract The 155-kDa complement regulator factor H (FH) is the predominant soluble regulatory protein of the complement system. It acts as a cofactor for the factor I-mediated conversion of the component C3b to iC3b, competes with factor B for a binding site on C3b and C3(H2O) and promotes the dissociation of the C3bBb complex. The primary site of synthesis is the liver, i.e. FH-specific mRNA and protein were identified in both hepatocytes (HC) and Kupffer cells (KC). Previous studies in rat primary HC and KC had shown that the proinflammatory cytokine IFN-, influences the balance between activation and inhibition of the complement system through up-regulation of the inhibitory FH. In this study we show that C5a, as a product of complement activation, stimulates the expression of FH-specific mRNA and protein in KC and thus induces a negative feedback. Quantitative-competitive RT-PCR showed an approximate threefold C5a-induced up-regulation of FH. ELISA analyses revealed a corresponding increase in FH protein in the supernatants of KC. The up-regulation of FH was completely inhibited by the C5a-blocking monoclonal antibody 6-9F. Furthermore, an involvement of LPS and IFN-, was excluded, which strongly indicates a direct effect of C5a on the expression of FH in KC. [source]

    Magneto,Structural Correlations in Discrete MnII -WV Cyano-Bridged Assemblies with Polyimine Ligands

    Robert Podgajny
    Abstract We present the magneto,structural correlations for two novel discrete cyano-bridged assemblies based on cationic complexes of manganese(II) with diimine ligands and octacyanotungstate(V) ions. The crystal structure of [MnII(terpy)(dmf)(H2O)2][MnII(terpy)(H2O)(dmf)(,-NC)WV(CN)7]26H2O (1) (terpy = 2,2,;6,,2,-terpyridine, dmf = dimethylformamide) contains dinuclear {MnIIWV}, cyano-bridged anions, while the crystal structure of [MnII(phen)3]2[MnII(phen)2(,-NC)2WV(CN)6]2(ClO4)29H2O (2) (phen = 1,10-phenanthroline) is built of tetranuclear {MnII2WV2}2, square anions. Intramolecular Mn,W magnetic interactions through the cyano bridges are represented by magnetic coupling constants J = ,39 cm,1 for the {MnIIWV}, unit in 1 and J1 = ,25.7 and J2 = ,16.7 cm,1 for the {MnII2WV2}2, unit in 2. J and J1 represent relatively strong W,CN,Mn interactions and are ascribed to the bridges in b positions of TPRS-8 (trigonal prism square-face bicapped) of [W(CN)8]3, polyhedra, favoring the strongest electronic interactions between the d,d orbital of W and the ,* orbitals of CN,, whereas J2 is related to the m vertex of [W(CN)8]3,. The magnetic properties of 1 and 2 are compared with reference compounds and discussed in the context of the type of coordination polyhedra of [W(CN)8]3, as well as the metric parameters of cyano-bridged W,CN,Mn linkages. We found the type of coordination polyhedra and bridging mode of [W(CN)8]3, to be the most important factors influencing the magnitude of the Mn,W magnetic interaction. [source]

    A Microporous Metal,Organic Framework with Immobilized ,OH Functional Groups within the Pore Surfaces for Selective Gas Sorption

    Zhenxia Chen
    Abstract A new two-dimensional microporous metal,organic framework Cu(BDC-OH)(H2O)0.5DEF [abbreviation: Cu(BDC-OH); H2BDC-OH = 2-hydroxybenzene-1,4-dicarboxylic acid; DEF = diethylformamide] with functional OH groups on the pore surfaces was solvothermally synthesized and structurally characterized. The activated Cu(BDC-OH) exhibits a moderate Langmuir surface of 584 m2,g,1, a pore volume of 0.214 cm3,g,1, and C2H2/CH4 and CO2/CH4 selectivity of 6.7 and 9.3, respectively, at 296 K, thereby highlighting the promise for its application in gas separation. [source]

    A Dynamically Entangled Coordination Polymer: Synthesis, Structure, Luminescence, Single-Crystal-to-Single-Crystal Reversible Guest Inclusion and Structural Transformation

    Arshad Aijaz
    Abstract A ZnII coordination polymer {[Zn2(cpa)2(bpy)]3H2O}n (1) (cpa2, = 4-(methoxycarbonyl)benzoate and bpy = 4,4,-bipyridine) has been synthesized under solvothermal condition and structurally characterized. This coordination polymer has nanotubular threefold entangled (2D,3D) structure with embedded water molecules; the water molecules can be partially exchanged in reversible single-crystal-to-single-crystal (SC-SC) fashion by different solvent molecules like methanol, ethanol and acetone giving rise to {[Zn2(cpa)2(bpy)](0.5MeOH)(2.5H2O)}n (2), {[Zn2(cpa)2(bpy)](0.5EtOH)(0.5H2O)}n (3) and {[Zn2(cpa)2(bpy)](0.5Me2CO)(H2O)}n (4). Inclusion of EtOH or MeOH leaves the size of the voids in the framework unaltered. Inclusion of acetone, however, is accompanied by shrinking of the voids in the framework. Heating of 1 at 100 C under vacuum for 4 h affords the de-solvated compound, {Zn2(cpa)2(bpy)}n (1,). Single-crystal X-ray structure of 1, shows sliding of the individual nanotubular components expanding the overall framework. Thus, the coordination polymer exhibits dynamic motion of the molecular components in SC-SC fashion. All compounds were further characterized via IR spectroscopy, PXRD, elemental and TGA analysis. When 1 is placed in benzene at 100 C for 2 days, compound {[Zn2(cpa)2(bpy)](2.5H2O)}n (5) is formed in a SC-SC fashion where coordination number of ZnII ion increases from four to five. Compound 1 also exhibits reversible guest-dependent photoluminescence properties. [source]

    Systematic Hydrothermal Investigation of Metal Phosphonatobenzenesulfonates by High-Throughput Methods

    Palanikumar Maniam
    Abstract A high-throughput (HT) investigation using the rigid bifunctional ligand 4-phosphonobenzenesulfonic acid, H2O3P-C6H4 -SO3H (H3L), generated five new phosphonatobenzenesulfonates with copper(II) or lead(II) ions. A comprehensive HT study comprising the screenings of different metal ions, metal salt types and the synthesis optimization were conducted whereby the influence of pH and molar ratios M2+/H3L were investigated. The HT-study led to five new compounds Pb2[(O3P-C6H4 -SO3)(OH)] (1), Cu1.5[(O3P-C6H4 -SO3)(H2O)] (2), NaCu(O3P-C6H4 -SO3)(H2O)3 (3), Cu2[(O3P-C6H4 -SO3)(OH)(H2O)] (4) and Cu3[(O3P-C6H4 -SO3)2(H2O)2] (5). Metal ion screening showed lead(II) and copper(II) to be suitable metal ions. The utilization of discovery and focused arrays allowed to determine the optimal formation fields of the respective compounds. The crystal structures were determined from single-crystal X-ray diffraction and revealed the presence of various MOx polyhedra that form clusters, chains or layers which are connected through the organic linker. IR spectra, thermogravimetric studies, magnetic susceptibility measurements and elemental analyses were conducted to further characterize the compounds 1, 3, 4 and 5. [source]

    Syntheses, Crystal Structures, and the Phase Transformation of Octacyanometallate-Based LnIII,WV Bimetallic Assemblies with Two-Dimensional Corrugated Layers

    Ai-Hua Yuan
    Abstract The reactions between Ln(NO3)3nH2O and (Bu3NH)3[W(CN)8]H2O have led to two series of octacyanometallate-based complexes: Ln(H2O)5[W(CN)8] [Ln = La(1), Pr(2), Nd(3), Eu(4), Gd(5)] and Ln(H2O)4[W(CN)8] [Ln = Ho(6), Er(7), Tm(8), Lu(9)]. The crystal structures of 1,9 have two-dimensional corrugated layers in which the LnIII and WV centres are linked in an alternating fashion. Thermogravimetric (TG) and powder XRD results reveal the presence of a phase transformation in the LnIII,WV system with increasing atomic number of the LnIII atoms. [source]

    Dual Luminescent Dinuclear Gold(I) Complexes of Terpyridyl-Functionalized Alkyne Ligands and Their Efficient Sensitization of EuIII and YbIII Luminescence

    Xiu-Ling Li
    Abstract Reaction of (tpyC6H4C,CAu)n {tpyC6H4C,CH = 4,-(4-ethynylphenyl)-2,2,:6,,2,-terpyridine} with diphosphane ligands Ph2P(CH2)xPPh2 (x = 2 dppe, 3 dppp, 4 dppb, 5 dpppen, 6 dpph) in CH2Cl2 afforded the corresponding dual luminescent binuclear gold(I) complexes [(tpyC6H4C,CAu)2(,-dppe)] (1), [(tpyC6H4C,CAu)2(, - dppp)] (2), [(tpyC6H4C,CAu)2(,-dppb)] (3), [(tpyC6H4C,CAu)2(,-dpppen)] (4), [(tpyC6H4C,CAu)2(,-dpph)] (5). Crystal structural analysis of complexes 12CH2Cl2 and 22CH2Cl2 show that the terpyridine moieties are free of coordination in these gold(I)-acetylide-phosphane complexes. Spectrophotometric titration between complex 1 and [Eu(tta)3] (Htta = 2-thenoyltrifluoroacetone) or [Yb(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) gave a 2:1 ratio between Ln(,-diketonate)3 (Ln = Eu, Yb) units and the complex 1 moiety, indicating the formation of Au2Ln2 complexes. Both the luminescence titrations and the luminescence quantum yields of Au2Ln2 (Ln = Eu, Yb) solutions show that the energy transfer occurs efficiently from the binuclear gold(I) antennas 1,5 to EuIII and YbIII centers, and all complexes 1,5 are good energy donors for sensitization of visible and NIR luminescence of EuIII and YbIII ions. [source]

    A CuIINiII Complex with Ethylenediamine: Crystal Structure and Ferromagnetic Behaviour of an Aqua-Bridged Heterometallic Chain Containing Ambidentate Ni(OAc)42, Blocks

    Oksana V. Nesterova
    Abstract A one-pot reaction of copper powder and nickel and ammonium acetates in a CH3OH solution of ethylenediamine (en) yields a unique 1D aqua-bridged polymer [Cu(en)2(,2 -H2O)2Ni(OAc)4]n4nH2O (1) with an ambidentate Ni(OAc)42, fragment that has not been previously characterized. The basic structural motif of 1 contains a previously unreported heterometallic M(,2 -H2O)M, aqua-bridge chain with alternating metal atoms. A complex system of N/O,HO hydrogen bonds strengthens the polymeric chains and links them into a supramolecular three-dimensional network. Variable-temperature magnetic susceptibility measurements of 1 revealed a weak ferromagnetic coupling (J = 1.1 cm,1) between the paramagnetic copper(II) and nickel(II) ions, which is transmitted through the oxygen bridges. [source]

    Strong Circularly Polarized Luminescence from Highly Emissive Terbium Complexes in Aqueous Solution

    Amanda P. S. Samuel
    Abstract Two luminescent terbium(III) complexes have been prepared from chiral ligands containing 2-hydroxyisophthalamide (IAM) antenna chromophores and their non-polarized and circularly-polarized luminescence properties have been studied. These tetradentate ligands, which form 2:1 ligand/TbIII complexes, utilize diaminocyclohexane (cyLI) and diphenylethylenediamine (dpenLI) backbones, which we reasoned would impart conformational rigidity and result in TbIII complexes that display both large luminescence quantum yield (,) values and strong circularly polarized luminescence (CPL) activities. Both TbIII complexes are highly emissive, with , values of 0.32 (dpenLI-Tb) and 0.60 (cyLI-Tb). Luminescence lifetime measurements in H2O and D2O indicate that while cyLI-Tb exists as a single species in solution, dpenLI-Tb exists as two species: a monohydrate complex with one H2O molecule directly bound to the TbIII ion and a complex with no water molecules in the inner coordination sphere. Both cyLI-Tb and dpenLI-Tb display increased CPL activity compared to previously reported TbIII complexes made with chiral IAM ligands. The CPL measurements also provide additional confirmation of the presence of a single emissive species in solution in the case of cyLI-Tb, and multiple emissive species in the case of dpenLI-Tb. [source]

    Syntheses, Structures and Magnetic Properties of Trinuclear CuIIMIICuII (M = Cu, Ni, Co and Fe) and Tetranuclear [21+12] CuIIMnII,2CuII Complexes Derived from a Compartmental Ligand: The Schiff Base 3-Methoxysalicylaldehyde Diamine Can also Stabilize a Cocrystal

    Arpita Biswas
    Abstract The present investigation describes syntheses, characterization and studies of the mononuclear compound [CuIIL,(H2O)] (1), the triangular, trinuclear monophenoxido-bridged compounds [{CuIIL}2MII(H2O)2](ClO4)2nH2O [2 (M = Cu, n = 0), 3 (M = Ni, n = 3), 4 (M = Co, n = 0), 5 (M = Fe, n = 0)] and the tetrametallic self-assembled complex [{CuIILMnII(H2O)3}{CuIIL}2](ClO4)2H2O (6) derived from compartmental Schiff base ligand, H2L, which is the [2+1] condensation product of 3-methoxysalicylaldehyde and trans -1,2-diaminocyclohexane. Single-crystal X-ray structures of 2, 5 and 6 were determined. Two pairs of terminalcentral metal ions in the trinuclear cores in 2 and 5 are monophenoxido-bridged. Interestingly, the CuO6 and FeO6 environments have tetragonally compressed octahedral geometries. On the other hand, the structure of 6 reveals that it is a [21+12] cocrystal of one diphenoxido-bridged dinuclear [CuIILMnII(H2O)3]2+ dication and two mononuclear [CuIIL] moieties. Cocrystallization in 6 takes place as a result of water encapsulation. The variable-temperature (2,300 K) magnetic susceptibilities of compounds 2,6 have been measured. The exchange integrals obtained are: the CuII3 compound 2, J = ,78.9 cm,1; the CuIINiIICuII compound 3, J = ,22.8 cm,1; the CuIICoIICuII compound 4, J = ,7.8 cm,1; the CuIIFeIICuII compound 5, J = ,3.0 cm,1; the CuII3MnII compound 6, J = ,15.1 cm,1. The monophenoxido-bridging core in 3 and 4 has been proposed after comparison of the structures and magnetic properties of these two compounds with those of 2, 5 and related other compounds. This paper presents rare examples of monophenoxido-bridged CuIIMIICuII (M = Cu, Ni, Co and Fe) compounds, provides an understanding of the structures from magnetic exchange integrals, and, most importantly, reports on the first example of a cocrystal derived from a 3-methoxysalicylaldehyde diamine compartmental ligand. [source]

    1,3,5-Triazapentadiene Nickel(II) Complexes Derived from a Ketoxime-Mediated Single-Pot Transformation of Nitriles

    Maximilian N. Kopylovich
    Abstract A series of cationic (2+) [Ni{HN=C(R)NHC(R)=NH}2](X)2 {R = 4-(Cl)C6H4 (1), 3-(NC)C6H4 (3), 4-(NC)C6H4 (4) and Me (7); X = Cl, (1, 3, 4) or MeCOO,H2O (7)} and neutral [Ni{HN=C(R)NC(R)=NH}2](solvate) {R = 3-(Cl)-4-py (2), 3-py (5) and 4-py (6); solvate = MeOH and/or H2O; py = pyridyl} N,N -chelating bis(1,3,5-triazapentadiene/ato)nickel(II) [Ni(tap)2]2+/0 complexes has been easily generated by a ketoxime-mediated single-pot reaction of a nickel(II) salt [NiCl22H2O or Ni(MeCOO)24H2O] with 4-chlorobenzonitrile, isophthalonitrile, terephthalonitrile, acetonitrile, 2-chloro-4-cyanopyridine, 3-cyanopyridine or 4-cyanopyridine, respectively. The obtained compounds have been characterized by IR, 1H and 13C{1H} NMR spectroscopy, FAB-MS(+) or ESI-MS(+), elemental analyses and single-crystal X-ray diffraction [for 7 and solvated mono- {1a(Me2CO)0.33(MeOH)0.67} and bis-deprotonated (2b2Me2CO, 4bCHCl3, 5bMe2CO and 6bMeOH) products, formed upon recrystallization of 1, 2, 4, 5 and 6, respectively]. The crystal structures of all compounds bear similar monomeric Ni(tap)2 units with a nearly square-planar geometry. In addition, the structure of 7 features the formation of infinite 1D zig-zag water,acetate chains {[(H2O)2(MeCOO)2]2,}n, which multiply interact with the [Ni(tap)2]2+ cations to generate a 2D hydrogen-bonded supramolecular assembly. [source]

    Thermal Decomposition Reactions as a Tool for the Synthesis of New Thermodynamic Metastable Modifications: Synthesis, Structures, and Properties of (Formato)nickel(II) Coordination Polymers Based on 4,4,-Bipyridine

    Jan Boeckmann
    Abstract The reaction of nickel formate with 4,4,-bipyridine (bipy) in aqueous solution at room temperature leads to the formation of the hydrated compound [Ni(HCO2)2(H2O)(bipy)4H2O]n (1) reported recently. On heating, compound 1 decomposes into the new anhydrous compound of composition [Ni(HCO2)2(bipy)]n (2II), which decomposes on further heating. Interestingly, if the anhydrous compound is prepared from solution, a new modification 2I is obtained. Investigations on the stability of both forms show that modification 2I presents the thermodynamically most stable form between room and decomposition temperature, whereas modification 2II, which can only be prepared by thermal decomposition, is metastable. In the crystal structure of 2I, the Ni2+ cations are coordinated by four ,2 - anti,anti bridging formato anions and two bridging ,2 -bipy ligands in a slightly distorted octahedralgeometry. The formato anions bridge the metal cations in zigzag chains, which are further connected by ,2 - anti,anti formato anions and bipy ligands to give a three-dimensional coordination network. IR spectroscopic investigations on the metastable form 2II also indicate that all formato anions act as bridging ligands. Magnetic measurements of the hydrated and anhydrous compounds reveal different behavior with a ferromagnetic ordering for compound 2I and an antiferromagnetic ordering for compound 1. For form 2II, only Curie,Weiss paramagnetism was found. [source]

    Synthesis and Characterization of 1-, 2-, and 3-Dimensional Bimetallic UO22+/Zn2+ Phosphonoacetates

    Karah E. Knope
    Abstract Four bimetallic UO22+/Zn2+ phosphonoacetates have been prepared from hydrothermal reactions of uranyl nitrate, zinc nitrate, and triethyl phosphonoacetate. These compounds, (UO2)2(PPA)2(H2O)2Zn(H2O)64H2O (1), (UO2)4(PPA)2(HPPA)2Zn(H2O)65H2O(2), (UO2)2(H2O)2(PPA)2Zn(H2O)4 (3), and (UO2)2(PPA)2(HPPA)Zn2(H2O)23(H2O) (4), adopt 1-, 2-, and 3-dimensional architectures wherein the UO22+ cation exhibits coordination preference for the phosphonate over the carboxylate oxygen atoms. The Zn2+ metal centers show an increased degree of ligand coordination with increasing reaction temperature. At 120 C, compounds 1 and 2 are formed. These structures are 1- and 2-dimensional, respectively, and contain fully hydrated [Zn(H2O)6]2+ cations. At 150 C and 180 C, the HPPA ligand displaces H2O molecules from the inner Zn2+ hydration sphere and binds to the metal centers via a ,CO2H oxygen atom in 3 and both carboxylate and phosphonate oxygen atoms in 4. The overall Zn2+ reaction can be expressed by the equation Zn(H2O)62+ + HPPA [rlarr2] Zn(H2O)5(HPPA) + H2O. Presented here are the syntheses, structures, and characterization of these materials. [source]

    Assembly of Dinuclear CuII Rigid Blocks by Bridging Azido or Poly(thiocyanato)chromates: Synthesis, Structures and Magnetic Properties of Coordination Polymers and Polynuclear Complexes

    Sergey V. Kolotilov
    Abstract Reaction of a dinuclear cationic copper(II) complex of 4,4,-[2-(3-hydroxyiminobutyl)imino]biphenyl [CuII2(LH)2]2+ with N3, resulted in the formation of a dinuclear azido [CuII2(LH)2(N3)2(H2O)2] complex or a 2D coordination polymer [CuII2(LH)2(N3)2]n. Reaction of the dinuclear complex with [CrIII(NCS)6]3, or [CrIII(NCS)4(NH3)2], produced a 2D polymer {[CuII2(LH)2(CH3CN)2]3[CrIII(NCS)6]2}n or a 1D chain, constructed from tetranuclear units {[CuII2(LH)2][CrIII(NCS)4(NH3)2]2}n. Structures of the compounds were determined by X-ray crystallography and complexes were characterised by the temperature dependency of the magnetic susceptibility and by ESR spectroscopy. Magnetic properties of homometallic compounds were fit with the model of a dimer with the Hamiltonian , = ,J,1,2. For heterometallic complexes ,MT curves were fit as the superposition of magnetism resulting from both [CuII2(LH)2]2+ and the adjacent CrIII -containing anion. J values for the complexes lie in the range from ,12.74(4) to ,17.77(8) cm,1. It was shown that the 4,4,-biphenyl bridge efficiently mediates exchange interactions. [source]

    Pillared Layered Metal Phosphonates Showing Field-Induced Magnetic Transitions

    Peng-Fei Wang
    Abstract The first examples of metal phosphonates based on 6-phosphononicotinic acid (pnaH3), namely, M3(pna)2(H2O)2 {1: M = CuII, 2: M = CoII} are reported. Both possess pillared layered structures. Within the inorganic layer, chains made up of dimers of edge-sharing {M2O6} octahedra and {M1O6} octahedra through O(1W), O,P,O, and O,C,O units are interconnected by {PO3C} tetrahedra. The pyridyl groups of pna3, serve as the pillars. An antiferromagnetic ground state is found for each compound. When the external field reaches critical points at low temperature, compound 1 features a spin flop transition, whereas 2 shows metamagnetic behavior. [source]

    Nucleophilic Addition of Water and Alcohols to Dicyanonitrosomethanide: Ligands with Diverse Bonding Modes in Magnetically Coupled d-Block Complexes

    Anthony S. R. Chesman
    Abstract Ligands resulting from the transition-metal-promoted nucleophilic addition of water or an alcohol to dicyanonitrosomethanide ions (dcnm) have been utilised in the formation of a large series of polynuclear complexes. Addition of water to dcnm results in formation of carbamoylcyanonitrosomethanide (ccnm); deprotonation of this ligand gives amidocarbonyl(cyano)nitrosomethanide (acnm), which has been incorporated into the trinuclear complex [Cu3(acnm)2(dmae)2(H2O)2] [dmae = 2-(dimethylamino)ethoxide] (1) which shows strong antiferromagnetic coupling with an exchange coupling constant, J = ,500 cm,1. [Cu(acnm)(NH3)2], (2) marks the first instance of acnm facilitating the formation of a coordination polymer, namely a 1D chain with intramolecular hydrogen bonding. Attempts to synthesise 2 through different reaction conditions instead resulted in the mononuclear [Cu(acnm)(NH3)2(py)] (py = pyridine) (3). The addition of ethanol to dcnm results in cyano[imino(ethoxy)methyl]nitrosomethanide (cenm) which features in the mononuclear [Cu(cenm)2(H2O)2] (4) and polymeric {[Cu(cenm)2]2H2O}, (5). The latter is the first example of the cenm ligand in a coordination polymer and has a highly unusual coordination mode through the nitrile groups and extremely weak antiferromagnetic coupling. {[Mn3(ccnm)2(EtOH)2(OAc)4]2EtOH}, (6) and (Et4N)2[Cu(ccnm)4] (7) contain previously unobserved coordination modes of the ccnm ligand while the complex [Mn(cmnm)3Mn(bipy)(MeOH)](ClO4) (8) {cmnm = cyano[imino(methoxy)methyl]nitrosomethanide, bipy = 2,2,-bipyridine} displays weak antiferromagnetic coupling between manganese atoms with J = ,1.44 cm,1. A change in the solvent systems used in the synthesis of 7 results in the formation of the mononuclear complexes [Mn(bipy)2(dcnm)2] (9) or [Mn(bipy)2(H2O)(dcnm)](dcnm)H2O (10) and [Mn(bipy)2(dcnm)(H2O)](dcnm) (11). The addition of ethlyene glycol monomethyl ether to dcnm gives cyano[imino(2-methoxyethoxy)methyl]nitrosomethanide (cgnm) and the formation of [Cu(cgnm)2(H2O)2] (12). [source]