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91.
K Butsch A Klein S Nitsche K Stirnat JR Hawkett EJ McInnes M Bauer 《Dalton transactions (Cambridge, England : 2003)》2012,41(37):11464-11475
The new copper complex [Cu(triaz)(2)] (Htriaz = 2,4-di-(tert-butyl)-6-(5-chloro-2H-benzo[d][1,2,3]triazol-2-yl)phenol) was investigated in detail by single crystal XRD, EPR-, UV/Vis-absorption-, CV-, and spectroelectrochemistry. The oxidised species [Cu(triaz)(2)](+) was characterised by UV/Vis spectroelectrochemistry and contains a phenoxyl-radical bound to Cu(ii). This quite stable species was chemically generated by two different methods: aerial oxidation of a Cu(i) precursor in the presence of Htriaz (and base) or from [Cu(triaz)(2)] by adding a Cu(ii) salt (disproportionation). The efficiency for the latter reaction has been studied by UV/Vis spectroscopy, XAS and catalytic test reactions (oxidation of benzyl alcohol). 相似文献
92.
93.
Rainer Bartsch Christian Müller Axel Fischer Peter G. Jones 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Syntheses and structures of penta- and hexaphosphorus analogues of ferrocene have been described recently1. Unlike their simple ferrocene analogues, these complexes have further ligating potential towards other transition metal centres by virtue of the availability of the ring phosphorus lone-pair electrons that are not involved in the η5-coordination. We now describe the first examples of coordination compounds of the triphospha-ferrocene [Fe(η5-C5Me5) (η5-C2 tBu2P3]. In the ruthenium complex [Fe(η5-C5Me5)(η5-C2 tBu2P3) Ru3(CO)9] 2 two adjacent phosphorus atoms of the η5-C2 tBu2P3 ring are interlinked by a ruthenium carbonyl cluster in which all three ruthenium atoms interact with the phosphorus atoms. The tetrametallic nickel complex [Fe(η5-C5Me5)(η5-C2 tBu2P3)Ni(CO)2]2 3 represents the first example of intermolecular interlinkage of two phospha-ferrocene systems by two metal centres. 相似文献
94.
New Ternary Clathrate Compounds in the Systems Barium–Indium/Zinc/Cadmium–Germanium: Zintl Compounds with Phase Width? By systematic investigations in the systems barium–indium/zinc/cadmium–germanium we found a couple of new electrovalent ternary compounds with A8X46 clathrate (I) type structures. They crystallize cubically in space-group Pm3n. For Ba8In16Ge30 (a = 1 075.8 pm), Ba8Zn8Ge38 (a = 1 082.0 pm) and Ba8Cd8Ge38 (a = 1 096.0 pm) the structures were verified by X-ray single crystal diffraction data. According to valence and bounding distances the new clathrates should be Zintl compounds. Measurements of the temperature dependence of the electrical resistivity proved, that they are indeed semiconductors. A part of the 2B/3B metal atoms can be substituted by germanium. Charge balance will be retained by creation of vacancies in the A8X46 type structures. By phase analysis the limits of the composition range were determined as Ba8In4Ge9[]3Ge30 (a = 1 084.9 pm), Ba8Zn4Ge10[]2Ge30 (a = 1 073.6 pm) and Ba8Cd4Ge10[]2Ge30 (a = 1 082.0 pm). 相似文献
95.
[PPh(4)][EI(4)] (E=As, Sb, Bi) salts were reacted with four and five equivalents of AgN(3) to form tetraazidopnictates and pentaazidopnictates of the type [PPh(4)][E(N(3))(4)] and [PPh(4)](2)[E(N(3))(5)], respectively. The synthesis of [PPh(4)][P(N(3))(4)] was also attempted from the reaction of P(N(3))(3) with [PPh(4)]N(3), but it yielded only the starting materials. Herein, we report the synthesis and structure elucidation of [PPh(4)][E(N(3))](4) (E=As, Sb) and pentaazidobismuthate, stabilized as the dimethyl sulfoxide (DMSO) anion adduct, [PPh(4)](2)[Bi(N(3))(5)(dmso)]. Successive anion formation along the series E(N(3))(3)+nN(3)(-) (n=1-3) and E(N(3))(5)+N(3)(-) was studied by density functional theory. 相似文献
96.
We present an automated microfluidic (MF) approach for the systematic and rapid investigation of carbon dioxide (CO(2)) mass transfer and solubility in physical solvents. Uniformly sized bubbles of CO(2) with lengths exceeding the width of the microchannel (plugs) were isothermally generated in a co-flowing physical solvent within a gas-impermeable, silicon-based MF platform that is compatible with a wide range of solvents, temperatures and pressures. We dynamically determined the volume reduction of the plugs from images that were accommodated within a single field of view, six different downstream locations of the microchannel at any given flow condition. Evaluating plug sizes in real time allowed our automated strategy to suitably select inlet pressures and solvent flow rates such that otherwise dynamically self-selecting parameters (e.g., the plug size, the solvent segment size, and the plug velocity) could be either kept constant or systematically altered. Specifically, if a constant slug length was imposed, the volumetric dissolution rate of CO(2) could be deduced from the measured rate of plug shrinkage. The solubility of CO(2) in the physical solvent was obtained from a comparison between the terminal and the initial plug sizes. Solubility data were acquired every 5 min and were within 2-5% accuracy as compared to literature data. A parameter space consisting of the plug length, solvent slug length and plug velocity at the microchannel inlet was established for different CO(2)-solvent pairs with high and low gas solubilities. In a case study, we selected the gas-liquid pair CO(2)-dimethyl carbonate (DMC) and volumetric mass transfer coefficients 4-30 s(-1) (translating into mass transfer times between 0.25 s and 0.03 s), and Henry's constants, within the range of 6-12 MPa. 相似文献
97.
Deraeve C Guo Z Bon RS Blankenfeldt W DiLucrezia R Wolf A Menninger S Stigter EA Wetzel S Choidas A Alexandrov K Waldmann H Goody RS Wu YW 《Journal of the American Chemical Society》2012,134(17):7384-7391
Post-translational attachment of geranylgeranyl isoprenoids to Rab GTPases, the key organizers of intracellular vesicular transport, is essential for their function. Rab geranylgeranyl transferase (RabGGTase) is responsible for prenylation of Rab proteins. Recently, RabGGTase inhibitors have been proposed to be potential therapeutics for treatment of cancer and osteoporosis. However, the development of RabGGTase selective inhibitors is complicated by its structural and functional similarity to other protein prenyltransferases. Herein we report identification of the natural product psoromic acid (PA) that potently and selectively inhibits RabGGTase with an IC(50) of 1.3 μM. Structure-activity relationship analysis suggested a minimal structure involving the depsidone core with a 3-hydroxyl and 4-aldehyde motif for binding to RabGGTase. Analysis of the crystal structure of the RabGGTase:PA complex revealed that PA forms largely hydrophobic interactions with the isoprenoid binding site of RabGGTase and that it attaches covalently to the N-terminus of the α subunit. We found that in contrast to other protein prenyltransferases, RabGGTase is autoinhibited through N-terminal (α)His2 coordination with the catalytic zinc ion. Mutation of (α)His dramatically enhances the reaction rate, indicating that the activity of RabGGTase is likely regulated in vivo. The covalent binding of PA to the N-terminus of the RabGGTase α subunit seems to potentiate its interaction with the active site and explains the selectivity of PA for RabGGTase. Therefore, psoromic acid provides a new starting point for the development of selective RabGGTase inhibitors. 相似文献
98.
99.
Axel Blau 《Current Opinion in Colloid & Interface Science》2013,18(5):481-492
Microelectrode arrays (MEAs) find application both in vitro and in vivo to record and stimulate electrical activity in electrogenic cells such as neurons, cardiomyocytes, pancreatic beta cells or immortalized cell lines derived therefrom (e.g., PC12, HL-1). In MEA electrophysiology, the quality of the predominantly extracellularly recorded or elicited electrical signals strongly depends on the distance, strength and stability of the interfacial contact between the electrogenic cells and an electrode. Decorating the substrate or electrode with biochemical adhesion factors and physical guidance cues does not only determine the tightness of that junction, but it also modulates substrate biocompatibility, its biostability, cell differentiation as well as cell fate. If an interface is furthermore topologically, chemically or physically patterned or constrained, neural interconnectivity may be steered towards directional organization. In this introductory and selective overview, we briefly discuss adhesion events at the chemical and biological level, review the general role and mechanisms of cell adhesion in (neuro)biology, then explore how cells adhere to artificial substrates. This will lead to the discussion of popular strategies for enhancing and steering interfacial interactions at the bio-hardware boundary with particular focus on MEA substrates. It will include a critical treatment of open issues with respect to the origin and shape of extracellularly recorded signals and their modulation by cell-culture-inherent events. 相似文献
100.
Organometallic 5d6 Transition Metal Complexes of 1‐Methyl‐(2‐alkylthiomethyl)‐1H‐benzimidazole Ligands: Structures and Electrochemical Oxidation The complexes [(mmb)Re(CO)3Cl], [(mtb)Re(CO)3Cl], [(mmb)OsCl(Cym)](PF6) and [(Cym)OsCl(mtb)](PF6) where Cym = p‐cymene, mmb = 1‐methyl‐(2‐methylthiomethyl)‐1H‐benzimidazole and mtb = 1‐methyl‐(2‐tert‐butylthiomethyl)‐1H‐benzimidazole were synthesized and, except for the latter, structurally characterized. In comparison with other late transition metal compounds of these N‐S chelate ligands the rhenium(I) systems exhibit a balanced coordination to both N and S donor atoms. Anodic one‐electron oxidation produces EPR‐silent rhenium(II) states whereas the osmium(III) species [(mmb)OsCl(Cym)]2+ could be identified via EPR and UV/VIS spectroelectrochemistry. 相似文献