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Arene
Kinds of Arene Terms modified by Arene Selected AbstractsAnalysis of lightning surge propagation in wind farmELECTRICAL ENGINEERING IN JAPAN, Issue 2 2008Yoh Yasuda Abstract Wind power generation is expected to become more important in future distribution systems. Although several prospective reports such as IEC 61400-24 and NREL SR-500-31115 indicate an insulation scheme and grounding design for lighting protection, there still seems to be too few investigations on the problems. This paper therefore discusses lightning surge analysis using a wind farm model with 2 or 10 ideal wind turbines. Changing parameters such as grounding resistance and lightning strike points, several cases were studied. As a result of the analysis using digital simulator ARENE, it is clear that the surge tends to propagate toward the end of a distribution line in a wind farm and there is the possibility of insulation accidents at the other wind turbines when lightning attacks a wind turbine. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 30, 38, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20364 [source] 16-Electron (Arene)ruthenium Complexes with Superbasic Bis(imidazolin-2-imine) Ligands and Their Use in Catalytic Transfer HydrogenationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 29-30 2009Thomas Glöge Abstract The ligands N,N, -bis(1,3,4,5-tetramethylimidazolin-2-ylidene)-1,2-ethanediamine (BLMe) and N,N, -bis(1,3-diisopropyl-4,5-dimethylimidazolin-2-ylidene)-1,2-ethanediamine(BLiPr) react with [(,5 -C5Me5)RuCl]4 to afford cationic 16-electron half-sandwich complexes [(,5 -C5Me5)Ru(BLR)]+ (R = Me, 3; R = iPr, 4), which resist coordination of the chloride counterion because of the strong electron-donating ability of the diimine ligands. Upon reaction with [(,6 -C6H6)RuCl2]2 or [(,6 -C10H14)RuCl2]2, these ligands stabilize dicationic 16-electron benzene and cymene complexes of the type [(,6 -C6H6)Ru(BLR)]2+ (R = Me, 5; R = iPr, 6) and [(,6 -C10H14)Ru(BLR)]2+ (R = Me, 7; R = iPr, 8). The X-ray crystal structure of [5]Cl2 reveals the absence of any direct Ru,Cl interaction, whereas a long Ru,Cl bond, supported by two CH···Cl hydrogen bonds, is observed for [(6)Cl]Cl in the solid state. Treatment of the dichlorides of 6 and 8 with NaBF4 affords [6](BF4)2 and [8](BF4)2, which are composed of individual dications and tetrafluoroborate ions with no direct Ru,F interaction. All complexes catalyze the transfer hydrogenation of acetophenone in boiling 2-propanol. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Tagging (Arene)ruthenium(II) Anticancer Complexes with Fluorescent LabelsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007Fabio Zobi Abstract Fluorescent (arene)ruthenium(II) complexes have been prepared by tagging a small fluorogenic reporter onto the chelating ligand of complexes of the type [(,6 -arene)RuCl(Z)]+ (Z = chelating ligand). Complexes [(,6 - p -cym)RuCl(NNO)](Cl) (2), [(,6 - p -cym)RuCl(L3)](Cl) (3) and [(,6 - p -cym)RuCl(L4)](Cl) (4) {p -cym = p- cymene, NNO = 2-[(2-aminoethyl)amino]ethanol, L3 = 2-[(2-aminoethyl)amino]ethyl-2-(methylamino)benzoate and L4 = N -{2-[(2-aminoethyl)amino]ethyl}-2-(methylamino)benzamide} were obtained in good yield from the reaction of the Ru dimer [(,6 - p -cym)RuCl2]2 (1) and the corresponding ligand. The compounds have been fully characterized and their X-ray crystal structures are reported. Compounds 3 and 4 show a photoluminescence response centered at 435 nm with partial fluorescence quenching of the fluorogenic reporters L3 and L4 upon coordination to the metal center. Species 2,4 show good solubility both in water and organic solvents. In water, 2,4 readily hydrolyze to form the aqua complexes. These are stable at acidic pH forming 10,15,% of the corresponding hydroxido complexes in buffered solution (25 mM HEPES) as the pH is raised to a physiological value (pH = 7.44). Under these conditions, 4 (but not 2 or 3) undergoes a fast pH-dependent reversible intramolecular rearrangement. Experimental data and semiempirical calculations indicate that the major species arising from this transformation is a complex with a tridentate chelating ligand following deprotonation at the nitrogen atom of the amide group. Esterase-catalyzed hydrolysis of 3 liberates isatoic acid (MIAH) and generates 2 indicating that the complex is a substrate for the enzyme. Complexes similar to 3 may have potential for esterase-activated Ru-based prodrug delivery systems.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C2 -Symmetrical 1,2-Diamine as AuxiliaryEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2006Alexandre Alexakis No abstract is available for this article. [source] Synthesis of An Enantioenriched C2 -Symmetric Molecule by a Chiral-Base-Mediated Kinetic Resolution of an (Arene)tricarbonylchromium(0) ComplexEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2006M. Paola Castaldi Abstract Trimethylsilyl substituents have been used to control the conformational preferences of a 1,2-disubstituted (arene)tricarbonylchromium(0) complex. The kinetic resolution of the mono-methyl derivative (±)- 11 using a chiral base/iodomethane quench sequence led to the synthesis of the enantioenriched C2 -symmetric bis-ether (+)- 13. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Diastereoselective Alkylation of (Arene)tricarbonylchromium and Ferrocene Complexes Using a Chiral, C2 -Symmetrical 1,2-Diamine as AuxiliaryEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2005Alexandre Alexakis Abstract The aminal of (benzaldehyde)tricarbonylchromium and en-antiopure bipyrrolidine undergoes diastereoselective ortho -metallation with butyllithium. Quenching with various electrophiles, followed by hydrolysis of the aminal, affords ortho -substituted (benzaldehyde)tricarbonylchromium compounds with high ee (91,99,%). When quenched with Ph2PCl, a new chiral P,N-bidentate ligand is obtained, which shows efficiency in Pd- and Cu-catalysed reactions. The aminal of ferrocenecarbaldehyde could also be formed, but the ortho -deprotonation occurs with only moderate diastereoselectivity (70,%). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Supramolecular Self-Assembled Dendritic Nonlinear Optical Chromophores: Fine-Tuning of Arene,Perfluoroarene Interactions for Ultralarge Electro-Optic Activity and Enhanced Thermal StabilityADVANCED MATERIALS, Issue 19 2009Xing-Hua Zhou Unprecedented electro-optic (EO) activity and excellent alignment stability at 85,°C are demonstrated through rational design of a new series of dendronized polyenic chromophores capable of supramolecular self-assembly directed by fine-tuned arene,perfluoroarene interactions. Analysis of the EO properties showed exceptional poling efficiency for these molecular glasses at high chromophore number density. [source] (,6 -Arene)ruthenium(N-heterocyclic carbene) Complexes for the Chelation-Assisted Arylation and Deuteration of Arylpyridines: Catalytic Studies and Mechanistic InsightsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Amparo Prades Abstract A series of (,6 -arene)ruthenium complexes have been tested in the arylation of arylpyridines. One (,6 - p -cymene)ruthenium(N-heterocyclic carbene) complex (labelled as 1 in the text) was found to be the most effective, being capable of arylating a wide set of substantially different arylpyridines. Complex 1 is also able to promote the regioselective deuteration of a series of arylated N-heterocycles, via a nitrogen-directed mechanism. Two of the deuterated amines were used to measure the kinetic isotope effect (KIE) in the arylation process. The detection of an inverse KIE, together with the observation that the CH activation process does not require the addition of a base, suggest that the rate-limiting step in the arylation process may be different to that of previously reported studies. [source] Transition Metal Arene ,-Complexes in Organic Synthesis and Catalysis.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Edited by E. Peter Kündig No abstract is available for this article. [source] Selective Preparation of 3,4,5-Trinitro-1H- Pyrazole: A Stable All-Carbon-Nitrated AreneANGEWANDTE CHEMIE, Issue 18 2010Grégoire Hervé Dr. Pernitriert: 3,4,5-Trinitro-1H- pyrazol (TNP, siehe Bild) ist das unerwartete Produkt der Nitrierung von 3,5-Dinitropyrazol mit einem starken Elektrophil, das aus 20,30,% Oleum und Salpeteräure entsteht. TNP ist bemerkenswert stabil, weil die Ringstruktur erhalten bleibt und die Konformation der Nitrogruppe an C4 die Acidität des Materials in Grenzen hält. [source] Übergangsmetallkatalysierte direkte Arylierungen von (Hetero)Arenen durch C-H-BindungsbruchANGEWANDTE CHEMIE, Issue 52 2009Lutz Ackermann Prof. Abstract Das Gebiet der übergangsmetallkatalysierten direkten Arylierung unter C-H-Bindungsbruch hat in den letzten Jahren eine rasante Entwicklung erfahren, was dazu führte, dass sich solche Methoden immer mehr als Alternativen zu den herkömmlichen Kreuzkupplungen mit metallorganischen Reagentien etabliert haben. Insbesondere wurden zahlreiche Palladium- und Rutheniumkatalysatoren beschrieben, welche die direkte Arylierung von (Hetero)arenen mit anspruchsvollen Reaktionspartnern ermöglichen; hierzu gehören elektrophile Arylchloride und -tosylate oder auch einfache Arene in gekreuzten dehydrierenden Arylierungen. [source] Arene,perfluoroarene interactions in crystal engineering.ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2001In the title complex, C6F6·C14H12, nearly parallel molecules of trans -stilbene and librationally disordered hexafluorobenzene form a mixed stack, with each molecule lying on an independent inversion centre. Adjacent stacks pack together in a herring-bone manner. [source] Lithiation Reactions Catalyzed by Linear and Cross-Linked Arene-Based Polymers.CHEMINFORM, Issue 7 2005Generation of Functionalized Organolithium Compounds. Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Reactivity of (,6 -Arene)tricarbonylchromium Complexes Toward Additions of Anions, Cations, and Radicals.CHEMINFORM, Issue 37 2001Craig A. Merlic Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] The Stereospecific Ligand Exchange at a Pseudo-Benzylic T -4 Iridium Centre in Planar-Chiral Cycloiridium (,6 -Arene)tricarbonylchromium ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 41 2009Jean-Pierre Djukic Dr. Abstract The stereospecificity of ligand exchange at the IrIII centre of a cycloiridium arenetricarbonylchromium complex has been established experimentally by various analytical methods as well as by X-ray diffraction structural analysis and computational investigations. Two new cases of phenyl and methyl iridium(III) complexes have been prepared by reaction of (,)-chlorido{2-[(tricarbonyl)(,6 -phenylene-,C1,)chromium(0)]pyridine-,N}(pentamethylcyclopentadienyl)iridium(III) with PhMgBr and MeMgBr. The determining influence of electrostatic repulsion has been established by means of density functional theory at the Becke,Perdew/TZP(ZORA) level by using, among other means, energy partitioning analysis. It is also shown that the Cr(CO)3 fragment is likely to ease the ionic cleavage of the IrCl bond in chlorido cycloiridium tricarbonylchromium complexes in a way similar to that already established for the solvolysis of benzyl halide complexes, that is, through a direct interaction of the Cr0 centre with the cationic IrIII centre. [source] Palladium-Catalyzed Formation of Highly Substituted Naphthalenes from Arene and Alkyne HydrocarbonsCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2008Yao-Ting Wu Prof. Abstract Several highly substituted naphthalenes 3 have been synthesized in a one-pot reaction by treatment of arenes 1 with alkynes 2 in the presence of palladium acetate and silver acetate. In this Pd-catalyzed protocol, an arene provides a benzo source for the construction of a naphthalene core through twofold aryl CH bond activation. Reaction of triphenylphosphine with diphenylethyne (2,a) under the catalysis of PdIV complexes produced 1,2,3,4-tetraphenylnaphthalene (3,ba) in 62,% yield. Here, triphenylphosphine undergoes one aryl CP bond cleavage and one aryl CH bond activation to serve as a benzo moiety. Crystal structures of cycloadducts 3,ea, 3,ga, and 3,ac have been analyzed. The twisted naphthalenes arise not only from the overcrowded substituents but also from the contribution of the CH3,, interaction. [source] Lower Rim Substituted p-tert -Butyl-Calix[4]arene.ELECTROANALYSIS, Issue 17-18 2009Abstract Tetrasubstituted p-tert- butylcalix[4]arene-thioamides (1,5) were applied as ionophores in ion-selective membrane electrodes (ISE) and were tested towards Pb-selectivity. The selectivity coefficients of the electrodes were determined. The tertiary calix[4]thioamides (1, 2) show remarkable selectivity for Pb(II) cations when compared with respectable calix[4]amides. The electrode membranes with those ligands are stable, the Pb-characteristics are close to nernstian within a wide linear range (,log c=6,1). Compounds 3,5, the secondary calix[4]thioamides form less stable electrode membranes. Complex formation constants of the ligands 1, 2, 3 and 5 with Pb(II) and some most interfering ions were determined. [source] Facilitated Transfer of Alkali Metal Ions by a Tetraester Derivative of Thiacalix[4]arene at the Liquid,Liquid InterfaceELECTROANALYSIS, Issue 12 2008Akgemci, Emine Guler Abstract The facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28-tetraethoxycarbonylmethoxy-thiacalix[4]arene across the water/1,2-dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half-wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li+ ion was not observed across the water/1,2-dichloroethane interface, the facilitated transfers were observed by formation of 1,:,1 (metal:ionophore) complex for Na+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1,:,2 (metal:ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log ,1°), and 8.36 (log ,2°), respectively. [source] Determination of Trace Amounts of Copper in Tap Water Samples with a Calix[4]arene Modified Carbon Paste Electrode by Differential Pulse Anodic Stripping VoltammetryELECTROANALYSIS, Issue 10 2007Çelik Canpolat Abstract A calix[4]arene modified carbon paste electrode was used for trace determination of copper. The study of the preconcentration of copper as well as the other heavy metal ions at the modified electrode, with subsequent measurement by differential pulse anodic stripping voltammetry (DPASV), indicates the efficient open-circuit accumulation of the analytes onto the electrode. Many parameters such as the composition of the paste, pH, preconcentration time and stirring rate influence the response of the measurement. The procedure was optimized for copper determination. For a 10-minute preconcentration time at pH,6.5,7.5, the detection limit (LOD) was 1.1,,g L,1. The optimized method was successfully applied to the determination of copper in tap water sample by means of standard addition procedure. The copper content of the sample was comparable with the result obtained with AAS method. [source] Electrocatalysis and Voltammetric Determination of Dopamine at a Calix[4]arene Crown-4 Ether Modified Glassy Carbon ElectrodeELECTROANALYSIS, Issue 4 2007Guo-Song Lai Abstract A sensitive and selective electrochemical method for the determination of dopamine (DA) was developed using a calix[4]arene crown-4 ether (CACE) film modified glassy carbon electrode (GCE). The modified electrode exhibited good electrocatalytic activity for electrochemical oxidation of DA in the pH,6.00 Britton,Robinson buffer solution, and ascorbic acid (AA) did not interfere with it. The diffusion coefficient (D=2.7×10,5,cm2 s,1), and the kinetic parameter such as the electron transfer coefficient (,=0.54) of DA at the surface of CACE were determined using electrochemical approaches. The catalytic oxidation peak currents showed a linear dependence on the DA concentration and a linear analytical curve was obtained in the range of 2.0×10,5,1.0×10,3,M of DA with a correlation coefficient of 0.9990. The detection limit (S/N=3) was estimated to be 3.4×10,6,M. This method was also examined for the determination of DA in an injection sample. In addition, effects of possible interferences were investigated. The present work shows the potential of the proposed method for the fabrication of a modified electrode, as it can be effectively used for voltammetric detection of DA. [source] Silver(I)-Selective PVC Membrane Potentiometric Sensor Based on a Recently Synthesized Calix[4]areneELECTROANALYSIS, Issue 10 2006Ayça Demirel Abstract A new PVC membrane potentiometric sensor for Ag(I) ion based on a recently synthesized calix[4]arene compound of 5,11,17,23-tetra- tert -butyl-25,27-dihydroxy-calix[4]arene-thiacrown-4 is developed. The electrode exhibits a Nernstian response for Ag(I) ions over a wide concentration range (1.0×10,2,1.0×10,6 M) with a slope of 53.8±1.6,mV per decade. It has a relatively fast response time (5,10,s) and can be used for at least 2 months without any considerable divergence in potentials. The proposed electrode shows high selectivity towards Ag+ ions over Pb2+, Cd2+, Co2+, Zn2+, Cu2+, Ni2+, Sr2+, Mg2+, Ca2+, Li+, K+, Na+, NH4+ ions and can be used in a pH range of 2,6. Only interference of Hg2+ is found. It is successfully used as an indicator electrode in potentiometric titration of a mixture of chloride, bromide and iodide ions. [source] Potentiometric Ag+ Sensors Based on Conducting Polymers: A Comparison between Poly(3,4-ethylenedioxythiophene) and Polypyrrole Doped with Sulfonated CalixarenesELECTROANALYSIS, Issue 18 2005Zekra Mousavi Abstract Potentiometric Ag+ sensors were prepared by galvanostatic electropolymerization of 3,4-ethylenedioxythiophene (EDOT) and pyrrole (Py) on glassy carbon electrodes by using sulfonated calixarenes as doping ions. Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) doped with p -sulfonic calix[4]arene (C4S), p -sulfonic calix[6]arene (C6S) and p -sulfonic calix[8]arene (C8S) were compared. PEDOT and PPy doped with poly(styrene sulfonate) (PSS) were also included for comparison. The analytical performance of the conducting polymer-based Ag+ sensors was studied by potentiometric measurements. All conducting polymer and dopant combinations showed sensitivity and selectivity to Ag+ compared to several alkali, alkaline-earth, and transition-metal cations. The type of the conducting polymer used for the fabrication of the electrodes was found to have a more significant effect on the selectivity of the electrodes to Ag+ than the ring size of the sulfonated calixarenes used as dopants. Selected conducting polymer-based sensors were studied by cyclic voltammetry (CV) and energy dispersive analysis of X-rays (EDAX) measurements. Results from the EDAX measurements show that both PEDOT- and PPy-based membranes accumulate silver. [source] Ruthenium-to-Platinum Interactions in ,6,,1 NCN-Pincer Arene Heterobimetallic Complexes: An Experimental and Theoretical StudyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 29 2010Sylvestre Bonnet Abstract A series of ,6,,1 -heterobimetallic complexes have been prepared in which a [Ru(,6 -arene)(C5R5)]+ fragment (R = H or Me) and an ,1 -NCN-pincer platinum fragment are combined within the same molecule. In complexes [2]+ and [3]+, the ruthenium and platinum centers are ,6 and ,1 coordinated, respectively, to the same arene ring, whereas in [4A]+ and [5A]+ they are coordinated to two different arene rings that are linked with a covalent bond ([4A]+) or an ethyl bridge ([5A]+). Upon changing the organic manifold between both metal centers, very strong ([2]+) to very weak ([5A]+) ruthenium-to-platinum interactions are obtained. Experimentally, X-ray crystal structures show an increaing steric hindrance when the Ru,Pt distance diminishes, and electrochemical and 195Pt NMR spectroscopic studies show a decreasing electron density on platinum from [5A]+ to [2]+. Theoretical DFT calculations were undertaken, which show an increasing charge on platinum from [5A]+ to [2]+. Our theoretical analysis shows that the particularly strong ruthenium-to-platinum electronic interactions in [2]+ and [3]+ do not come from binding of ruthenium to platinum, but from the pincer Cipso sharing its electron density between both metal centers, which decreases the , donation to platinum, and from increased backdonation of the platinum d electrons into the , system of the arene ring. [source] Isostructural Potassium and Thallium Salts of Sterically Crowded Thio- and Selenophenols: A Structural and Computational StudyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2008Denis Bubrin Abstract Because of their similar cationic radii, potassium and thallium(I) compounds are usually regarded as closely related. Homologous molecular species containing either K+ or Tl+ are very rare, however. We have synthesized potassium and thallium salts MEAr* [M, E = K, S (2a); K, Se (2b); Tl, S (3a); Tl, Se (3b); Ar* = 2,6-Trip2C6H3, Trip = 2,4,6- iPr3C6H2] derived from terphenyl-substituted thio- and selenophenols. In the solid-state structures of dimeric 2a, 2b, 3a, and 3b additional metal-,n,,-arene interactions to the flanking arms of the terphenyl substituents of different hapticity n are observed. Remarkably, the homologous potassium and thallium complexes 2b and 3b crystallize in isomorphous cells. For 2a, 3a, and model complexes of the composition METph (Tph = C6H4 -2-Trip) the nature of the M,E and M···C(arene) bonding was studied by density functional theory calculations.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Heterometallic CoIII,LnIII (Ln = Gd, Tb, Dy) Complexes on a p -Sulfonatothiacalix[4]arene Platform Exhibiting Redox-Switchable Metal-to-Metal Energy TransferEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2008Viktoriya Skripacheva Abstract Nuclear magnetic relaxation along with pH metric data have been used to reveal pH-dependent heterometallic CoIII,LnIII (Ln = Gd, Tb, and Dy) complex formation on a p -sulfonatothiacalix[4]arene (TCAS) platform in aqueous solution. The previously obtained 1D and 2D 1H NMR spectroscopic and X-ray data prove the outer sphere binding of the CoIII block with the upper rim of TCAS, whereas the LnIII ion is coordinated with the phenolate groups of the lower rim of TCAS. The inclusive outer-sphere binding of CoIII tris(dipyridyl) and tris(ethylendiaminate) complexes with the upper rim of TCAS favors binding of the inner-sphere lanthanide ions through the lower rim of TCAS, whereas noninclusive binding of CoIII bis(histidinate) provides no effect on the binding of lanthanide ions. The emission properties of [Co(dipy)3]3+,LnIII (Ln = Gd, Tb, Dy) complexes indicate the quenching of 4f luminescence by the 3d block. This quenching can be switched off by electrochemical CoIII/CoII reduction with further switching on by reoxidation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Self-Assembly of p -Sulfonatocalix[4]arene and a Ag,hmt Coordination Polymer into a Porous StructureEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2008Guo-li Zheng Abstract A novel porous material constructed from p -sulfonatocalix[4]arene molecules and a AgI coordination polymer has been structurally characterized. The porous supramolecular complex features a bilayer arrangement of p -sulfonatocalix[4]arene molecules linked by a AgI,hmt (hmt: hexamethylenetetramine) coordination polymer through metal,ligand bonding, hydrogen bonding and host,guest interactions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Developing the Kharasch Reaction in Aqueous Media: Dinuclear Group 8 and 9 Catalysts Containing the Bridging Cage Ligand Tris(1,2-dimethylhydrazino)diphosphane,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2008Alba E. Díaz-Álvarez Abstract The dinuclear complexes [{RuCl2(,6 - p -cymene)}2(,-THDP)] (4) and [{MCl(,4 -cod)}2(,-THDP)] [M = Rh (5), Ir (6)], containing the bridging cage-type ligand tris(1,2-dimethylhydrazino)diphosphane (THDP), have been synthesized in high yields (89,95,%) by treatment of dimers [{RuCl(,-Cl)(,6 - p -cymene)}2] (1) and [{M(,-Cl)(,4 -cod)}2] [M = Rh (2), Ir (3)] with one equivalent of THDP. The structure of the (,6 -arene)ruthenium(II) derivative 4 has been unequivocally confirmed by means of X-ray diffraction methods. All these complexes have been found to be active catalysts for the atom-transfer radical addition of bromotrichloromethane to olefins (Kharasch reaction) in heterogeneous aqueous media under mild conditions (room temp.).(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Expanding the Range of "Daniphos"-Type P,P- and P,N-Ligands: Synthesis and Structural Characterisation of New [(,6 -arene)Cr(CO)3] ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 31 2007Elisabetta Alberico Abstract New P,P- and P,N-ligands have been synthesised whose core structure is an [(,6 -arene)Cr(CO)3] unit. These new ligands, which extend the range of "Daniphos" ligands, are endowed with central and planar chirality and have been prepared through a stereoselective synthetic strategy from optically pure benzylamines bearing a second substituent on the arene other than the benzyldimethylamino group. Because the two faces of unsymmetrically 1,2- and 1,3-disubstituted benzylamine are diastereotopic, which means that diastereomeric complexes arise upon coordination of theCr(CO)3 fragment to either of these two faces, the synthetic plan has been adjusted by exploiting the trimethylsilyl group as a temporary steric modulator in order to access both complexes with high diastereoselectivity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis and Crystallographic Characterisation of the Heterodimetallic Complex [(Dibenzo-18-crown-6)K(,-Cl)3Ru(,6 - p -cymene)]EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2007Carsten A. Vock Abstract The triple-chlorido-bridged heterodimetallic dinuclear complex [(dibenzo-18-crown-6)K(,-Cl)3Ru(,6 - p -cymene)] containing an (,6 -arene)RuII fragment and a Group 1 metal crown ether fragment was synthesized and characterized by spectroscopy and X-ray crystallography. The solid-state structure clearly reveals the presence of the triple-chlorido-bridged dinuclear complex, whereas NMR investigations in different deuteriated solvents reveal the presence of an essentially 1:1 mixture of 1 and starting materials, indicating the presence of a dynamic equilibrium. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Tagging (Arene)ruthenium(II) Anticancer Complexes with Fluorescent LabelsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007Fabio Zobi Abstract Fluorescent (arene)ruthenium(II) complexes have been prepared by tagging a small fluorogenic reporter onto the chelating ligand of complexes of the type [(,6 -arene)RuCl(Z)]+ (Z = chelating ligand). Complexes [(,6 - p -cym)RuCl(NNO)](Cl) (2), [(,6 - p -cym)RuCl(L3)](Cl) (3) and [(,6 - p -cym)RuCl(L4)](Cl) (4) {p -cym = p- cymene, NNO = 2-[(2-aminoethyl)amino]ethanol, L3 = 2-[(2-aminoethyl)amino]ethyl-2-(methylamino)benzoate and L4 = N -{2-[(2-aminoethyl)amino]ethyl}-2-(methylamino)benzamide} were obtained in good yield from the reaction of the Ru dimer [(,6 - p -cym)RuCl2]2 (1) and the corresponding ligand. The compounds have been fully characterized and their X-ray crystal structures are reported. Compounds 3 and 4 show a photoluminescence response centered at 435 nm with partial fluorescence quenching of the fluorogenic reporters L3 and L4 upon coordination to the metal center. Species 2,4 show good solubility both in water and organic solvents. In water, 2,4 readily hydrolyze to form the aqua complexes. These are stable at acidic pH forming 10,15,% of the corresponding hydroxido complexes in buffered solution (25 mM HEPES) as the pH is raised to a physiological value (pH = 7.44). Under these conditions, 4 (but not 2 or 3) undergoes a fast pH-dependent reversible intramolecular rearrangement. Experimental data and semiempirical calculations indicate that the major species arising from this transformation is a complex with a tridentate chelating ligand following deprotonation at the nitrogen atom of the amide group. Esterase-catalyzed hydrolysis of 3 liberates isatoic acid (MIAH) and generates 2 indicating that the complex is a substrate for the enzyme. Complexes similar to 3 may have potential for esterase-activated Ru-based prodrug delivery systems.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] | ||||||||||||||||||||||||||||||||||||||||