Search results for "SPLIT"
showing 10 items of 362 documents
Syntheses, structural characterisation and magnetic properties of Fe(ii) and Mn(ii) compounds with the pentacyanopropenido ligand; structural charact…
2006
International audience; Reactions between the metal(II) salts [M(CH3CN)n](BF4)2 (M = Fe, n = 6; M = Mn, n = 4) and some organic anionic polynitriles were studied. With the pentacyanopropenide anion pcp− [pcp− = (NC)2CC(CN)C(CN)2−], were obtained, according to the experimental conditions, the new complexes [M(pcp)2(H2O)4] (1, M = Fe; 2, M = Mn) and [M(pcp)2] (3, M = Fe; 4 = Mn). Use of the hexacyano-3,4-diazahexadienediide anion [(NC)2CC(CN)NNC(CN)C(CN)22−] instead of pcp− did not afford polynitrile metal complexes but led to a new organic derivative 5, of formula C10N8H2. Crystallographic studies indicated that the isostructural compounds 1 and 2 involve discrete monomeric units with pcp li…
Organometallic complexes with biological molecules II. Synthesis, solid-state characterization andin vivo Cytotoxicity of Diorganotin(IV)chloro and T…
1994
Several new diorganotin(IV)chloro and triorganotin(IV)chloro penicillin G derivatives have been prepared. The isolated compounds showed 1:1 stoichiometry, with formulae R2SnClpenG and R3SnClpenGNa, respectively (penG− = penicillin G− = 4- thia - 1 - azabicyclo[3.2.0]heptane-2-carboxylate, 3,3-dimethyl-7-oxo-6-(2-phenylacet-amido) anion; R = Me, Bu, Ph). The coordination environment around the the tin(IV) atom, in all of the complexes, was trigonal bipyramidal. Penicillin G behaved as a monoanionic, bismonodentate ligand in R2SnClpenG through the β-lactamic carbonyl and unidentate ester-type carboxylate anion, and as unidentate through the β-lactamic carbonyl in R3SnClpenGNa, as inferred on …
Structural characterization of triorganotin(IV) complexes with sodium fusidate and DFT calculations
2010
Abstract Three new complexes of the steroid sodium fusidate (sodium 2-[(1 S ,2 S ,5 R ,6 S ,7 S ,10 S ,11 S ,13 S , 14 Z ,15 R ,17 R )-13-(acetyloxy)-5,17-dihydroxy-2,6,10,11-tetramethyl tetracyclo[8.7.0.0 2,7 .0 11,15 ] heptadecan-14-ylidene]-6-methylhept-5-enoate = (NaFusidate, Na FA )]), with triorganotin(IV) moieties have been prepared and investigated by conventional techniques as FTIR, Mossbauer, ESI-MS and NMR spectroscopy. The isolated compounds showed stoichiometries organotin(IV)/fusidate 1/1, R 3 Sn(IV) FA (R = Me, FA1 ; Bu, FA2 ; Ph, FA3 ). The ligand coordination sites were determined by FTIR spectroscopic measurements. In the complexes, the carboxylate group of the fusidate li…
Experimental Investigation of Fused Biconical Fiber Couplers for Measuring Refractive Index Changes in Aqueous Solutions
2016
A detailed experimental study of a simple and compact fiber optic sensor based on a fused biconical fiber coupler is presented, in which the sensitivity is improved by operating the coupler beyond the first coupling cycle. The sensor is demonstrated to perform high sensitivity measurements of refractive index changes by means of variation of sugar concentration in water. The device is operated to achieve a linear transmission response, allowing a linear relation between the sugar concentration and the output signal. The initial sensitivity was measured as 0.03 units of normalized transmission per unit of sugar concentration (g/100 mL), with a noise detection limit of a sugar concentration o…
Broadband focused waves with compensated spatial dispersion: transverse versus axial balance.
2007
We determine the constraints an ABCD optical system must verify to achieve, at the focal region, broadband waves with compensated spatial dispersion either along the optical axis, called on-axis isodiffracting fields, or in the lateral direction, here named in-plane isodiffracting beams. An optical configuration is identified for generating both types of achromatic broadband focused wave fields. An experimental verification is also provided.
Electronic properties and high-pressure behavior of wolframite-type CoWO4
2021
In this work we characterize wolframite-type CoWO4 under ambient conditions and under compression up to 10 GPa, with emphasis on its electronic structure. X-Ray diffraction and vibrational experiments, supported by ab initio calculations, show that CoWO4 is stable under high-pressure conditions, as no structural changes are detected in the studied pressure range. Interesting findings come from optical absorption spectroscopy. On the one hand, CoWO4 is confirmed to have one of the lowest band gaps among similar wolframites, around 2.25 eV. This makes CoWO4 suitable for use in applications such as the photocatalysis of organic pollutants and water splitting. Additionally, a monotonic decrease…
Diffusion stabilizes cavity solitons in bidirectional lasers
2009
We study the influence of field diffusion on the spatial localized structures (cavity solitons) recently predicted in bidirectional lasers. We find twofold positive role of the diffusion: 1) it increases the stability range of the individual (isolated) solitons; 2) it reduces the long-range interaction between the cavity solitons. Latter allows the independent manipulation (writing and erasing) of individual cavity solitons.
Crystal structure, magnetic and spectroscopic properties of copper(II) formato dimethylformamide: a new tetracarboxylato-bridged copper(II) dimer
2002
Abstract The crystal and molecular structure of a new tetracarboxylato copper(II) dimer [bis(dimethylformamide)tetrakis(μ-formato)dicopper(II)], has been determined by X-ray diffraction methods. The crystal structure consists of a centrosymmetric dimer [Cu2(HCOO)4(dmf)2], where four bidentate formato anions form syn–syn bridges between the metal ions which are in a 4+1 environment. Magnetic susceptibility data show that the copper ions are strongly antiferromagnetically coupled with J=−470 cm−1. The EPR spectrum shows a characteristic pattern of a triplet state with a D zero field splitting value of 0.27 cm−1.
Split-ticket voting in German Federal elections, 1953–90: an example of sophisticated balloting?
1999
Abstract Though the German electoral system has provided the opportunity of split-ticket voting since 1953, until now there has only been mere speculation concerning the rationality of ticket-splitting. In this paper we examine the rationality thesis empirically, using data provided by the official representative electoral statistics of the Federal Republic. Modifying the Downsian notion of rational voting, rational ticket-splitting is defined in terms of coalition building and of voters' expectations of the electoral success of candidates and parties. Applying this conceptual framework, it will be shown that the combinations of first and second votes actually chosen by a majority of the Ge…
Distance graphs and the T-coloring problem
1999
Abstract The T-coloring problem is, given a graph G = (V, E), a set T of nonnegative integers containing 0, and a ‘span’ bound s ⩾ 0, to compute an integer coloring f of the vertices of G such that |f(ν) − f(w)| ∉ T ∀νw ∈ E and max f − min f ⩽ s. This problem arises in the planning of channel assignments for broadcast networks. When restricted to complete graphs, the T-coloring problem boils down to a number problem which can be solved efficiently for many types of sets T. The paper presents results indicating that this is not the case if the set T is arbitrary. To these ends, the class of distance graphs is introduced, which consists of all graphs G : G ≅ G(A) for some (finite) set of posi…