Novel Unsymmetrical Ru(III) and Mixed-valence Ru(III)/Ru(II) Dinuclear Compounds Related to the Antimetastatic Ru(III) Drug NAMI-A

In this paper we report the stepwise preparation and the characterization of new unsymmetrical monoanionic Ru(III) dinuclear compounds, [NH4][{trans-RuCl4(Me2SO-S)}(μ-L){mer-RuCl3(Me2SO-S)(Me2SO-O)}] (L = pyz (1), pym (2)). By a similar synthetic approach we also prepared new mixed-valence Ru(III)/Ru(II) dinuclear compounds of formula [NH4][{trans-RuCl4(Me2SO-S)}(μ-pyz){cis,cis,cis-RuCl2(Me2SO-S)2(CO)}] (L = pyrazine (pyz, 3), pyrimidine (pym, 4)). Moreover, we describe the chemical behavior of compounds 1-4 in physiological solution, also after complete reduction (with ascorbic acid) to the corresponding Ru(II)/Ru(II) species. Overall, the chemical behavior of 1 and 2 after reduction resembles that of the corresponding dianionic and neutral dinuclear species, [{trans-RuCl3(Me2SO-S)}2(μ-L)]2−and [{mer-RuCl3(Me2SO-S)(Me2SO-O)}2 (μ-L)]. On the other hand, the mixed-valence dinuclear compounds 3 and 4, owing to the great inertness of the cis,cis,cis-RuCl2(Me2SO-S)2(CO)(1/2μ-L) fragment, behave substantially like the mononuclear species [trans-RuCl4(Me2SO-S)(L)]− in which the terminally bonded L ligand can be considered as bearing a bulky substituent on the other N atom

Iron complexes with nitrogen bidentate ligands as green catalysts foralcohol oxidation

The iron(II) complexes [Fe(N-N)3](OTf)2(N-N = 2,2- bipyridine, 1,10-phenanthroline and substitutedderivatives) were employed as catalyst precursors for the oxidation of primary and secondary alcohols,including glycerol. The single-crystal structure of [Fe(bipy)3](OTf)2was determined by X-ray crystallog-raphy.The catalytic reactions were performed using either H2O2or tert-butilhydroperoxide (TBHP) asoxidating agent, in mild experimental conditions: with all catalysts employed, secondary alcohols wereoxidized to the corresponding ketones with up to 100% yields, whereas other substrates gave lowerconversions. Indications on the nature of the catalytically active species, which is probably formed viadissociation of a nitrogen ligand from the iron center, were obtained from NMR and ESI\u2013MS spectra

The contradictory effect of the methoxy-substituent in palladium-catalyzed ethylene/methyl acrylate cooligomerization

Two new nonsymmetric bis(aryl-imino)acenaphthene ligands (Ar,Ar'-BIAN) and one symmetric Ar2-BIAN were studied. The three ligands share the presence of at least one methoxy group on one of the two aryl rings. These ligands were used for the synthesis of neutral and monocationic palladium(II) complexes of general formula [Pd(CH3)Cl(N-N)] and [Pd(CH3)(L)(N-N)][PF6] (N-N = Ar,Ar'-BIAN, Ar2-BIAN; L = CH3CN, dmso). Due to the nonsymmetric nature of the ligands and their coordination to palladium in a nonsymmetric chemical environment, cis and trans isomers are possible for the three series of complexes with Ar,Ar'-BIANs. Both a detailed NMR investigation in solution and the X-ray characterization in solid state point out that the trans isomer is the preferred species for the neutral derivatives, whereas for the cationic compounds a decrease in the stereoselectivity of the coordination is observed. One of the new Ar,Ar'-BIANs differs from an already reported nonsymmetric \uf061-diimine for the replacement, on one aryl ring, of a methyl group with a methoxy susbtituent, thus allowing a comparison of the structural features of the relevant complexes. The monocationic complexes were tested as precatalysts for the ethylene/methyl acrylate copolymerization under mild reaction conditions. Despite the structural similarities observed in solution with the already known precatalysts, the present compounds demonstrated a remarkable decrease in the productivity values associated to a higher affinity for the polar monomer

2,4-Dimethoxy­benzaldehyde azine

The title mol­ecule, C18H20N2O4, is located on a crystallographic centre of symmetry. The meth­oxy groups are coplanar with the benzene ring [interplanar angles of 14.4 (2) and 3.1 (3)°], indicating a conjugation effect

Two-colour generation in a chirped seeded Free-Electron Laser

We present the experimental demonstration of a method for generating two spectrally and temporally separated pulses by an externally seeded, single-pass free-electron laser operating in the extreme-ultraviolet spectral range. Our results, collected on the FERMI@Elettra facility and confirmed by numerical simulations, demonstrate the possibility of controlling both the spectral and temporal features of the generated pulses. A free-electron laser operated in this mode becomes a suitable light source for jitter-free, two-colour pump-probe experiments

(E)-4-Octyloxybenzaldehyde thio­semicarbazone

In the title compound, C16H25N3OS, the thio­semicarbazone group adopts an E configuration with respect to the C=N bond and is almost coplanar with the benzene ring, forming a dihedral angle of 9.3 (1)°. In the crystal packing, the mol­ecules lie along the a axis in an anti­parallel arrangement and are held in place by van der Waals inter­actions. As a consequence, there is relatively low anisotropic thermal motion in the terminal atoms of the n-octyl chain

Using XDAQ in Application Scenarios of the CMS Experiment

XDAQ is a generic data acquisition software environment that emerged from a rich set of of use-cases encountered in the CMS experiment. They cover not the deployment for multiple sub-detectors and the operation of different processing and networking equipment as well as a distributed collaboration of users with different needs. The use of the software in various application scenarios demonstrated the viability of the approach. We discuss two applications, the tracker local DAQ system for front-end commissioning and the muon chamber validation system. The description is completed by a brief overview of XDAQ.Comment: Conference CHEP 2003 (Computing in High Energy and Nuclear Physics, La Jolla, CA

The CMS Event Builder

The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragments of 8 data sources. The second stage combines the 64 super-fragments into full events. This architecture allows installation of the second stage of the event builder in steps, with the overall throughput scaling linearly with the number of switches in the second stage. Possible implementations of the components of the event builder are discussed and the expected performance of the full event builder is outlined.Comment: Conference CHEP0

Complex Molecules That Fold Like Proteins Can Emerge Spontaneously

Folding can bestow macromolecules with various properties, as evident from nature\u2019s proteins. Until now complex folded molecules are the product either of evolution or of an elaborate process of design and synthesis. We now show that molecules that fold in a well-defined architecture of substantial complexity can emerge autonomously and selectively from a simple precursor. Specifically, we have identified a self-synthesizing macrocyclic foldamer with a complex and unprecedented secondary and tertiary structure that constructs itself highly selectively from 15 identical peptide-nucleobase subunits, using a dynamic combinatorial chemistry approach. Folding of the structure drives its synthesis in 95% yield from a mixture of interconverting molecules of different ring sizes in a one-step process. Single-crystal X-ray crystallography and NMR reveal a folding pattern based on an intricate network of noncovalent interactions involving residues spaced apart widely in the linear sequence. These results establish dynamic combinatorial chemistry as a powerful approach to developing synthetic molecules with folding motifs of a complexity that goes well beyond that accessible with current design approaches. The fact that such molecules can form autonomously implies that they may have played a role in the origin of life at earlier stages than previously thought possibl