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In this article, we report on the synthesis and characterization of the tetracarboxylatodirhodium(II) complexes [Rh2(&mu, &ndash, O2CCH2OMe)4(THF)2] (1) and [Rh2(&mu, O2CC6H4&ndash, p&ndash, CMe3)4(OH2)2] (2) by metathesis reaction of [Rh2(&mu, O2CMe)4] with the corresponding ligand acting also as the reaction solvent. The reaction of the corresponding tetracarboxylato precursor, [Rh2(&mu, O2CR)4], with PPh4[Au(CN)2] at room temperature, yielded the one-dimensional polymers (PPh4)n[Rh2(&mu, O2CR)4Au(CN)2]n (R = Me (3), CH2OMe (4), CH2OEt (5)) and the non-polymeric compounds (PPh4)2{Rh2(&mu, O2CR)4[Au(CN)2]2} (R = CMe3 (6), C6H4&ndash, CMe3 (7)). The structural characterization of 1, 3&middot, 2CH2Cl2, 4&middot, 3CH2Cl2, 5, 6, and 7&middot, 2OCMe2 is also provided with a detailed description of their crystal structures and intermolecular interactions. The polymeric compounds 3&middot, 3CH2Cl2, and 5 show wavy chains with Rh&ndash, Au&ndash, Rh and Rh&ndash, N&ndash, C angles in the ranges 177.18&deg, 178.69&deg, and 163.0&deg, 170.4&deg, respectively. A comparative study with related rhodium-silver complexes previously reported indicates no significant influence of the gold or silver atoms in the solid-state arrangement of these kinds of complexes.

Herein, we describe the preparation of heteronuclear dirhodium-silver complexes by reaction between molecular Rh(II)-Rh(II) compounds [Rh2(&mu, O2CR)4L2] (R = Me, Ph (1), CH2OEt (2), L = solvent molecules) with paddlewheel structure and PPh4[Ag(CN)2]. One-dimensional coordination polymers of (PPh4)n[Rh2(&mu, O2CR)4Ag(CN)2]n (R = Me (3), Ph (4), CH2OEt (5)) formula have been obtained by replacement of the two labile molecules in the axial positions of the paddlewheel structures by a [Ag(CN)2]&minus, bridging unit. The crystal structures of 3&ndash, 5 display a similar arrangement, having anionic chains with a wavy structure and bulky (PPh4)+ cations placed between the chains. The presence of the (PPh4)+ cations hinders the existence of intermolecular Ag-Ag interactions although several C-H&middot, &middot, &pi, interactions have been observed. A similar reaction between [Rh2(&mu, O2CCMe3)4(HO2CCMe3)2] and PPh4[Ag(CN)2] led to the molecular compound (PPh4)2{Rh2(&mu, O2CCMe3)4[Ag(CN)2]2} (6) by replacement of the axial HO2CCMe3 ligands by two [Ag(CN)2]&minus, units. The trimethylacetate ligand increases the solubility of the complex during the crystallization favouring the formation of discrete heteronuclear species.

This article describes the synthesis of isonitrosomethyl-p-tolyl ketone [HL] as the starting compound and then we prepared the new oxime ligand from the reactions of the amine materials with 1,2-diaminobenzene [H2L1]. (1E, 2E, 1'E, 2'E)-3,3'-bis [(4-tolyl ketone)-(1,2 phenylene diimine)]. Acetaldehyde dioxime ligand was used to synthesize the metal complexes. The complexes were elucidated by FT-IR, elemental analysis, magnetic moment measurements, molar conductivity, mass spectra, and TGA studies. The free ligand was also described with its13C and1H-NMR spectra. For complexes using spectroscopic and stoichiometric data of the complexes showed that metal:ligand ratio of mononuclear copper(II) complex was found to be 1:1 while this ratio was 2:1 in homo-and heterodinuclear copper(II) complex and 3:2 in the trinuclear copper(II) complex. All these data show us that the proposed structure is consistent with the obtained data. © 2018, Turkish Chemical Society. All rights reserved.

Enzymatic addition of GalNAc to isotopically labeled IFNα2a produced in Escherichia coli yielded the O-linked glycoprotein GalNAcα-[ 13C,15N]IFNα2a. The three-dimensional structure of GalNAcα-IFNα2a has been determined in solution by NMR spectroscopy at high resolution. Proton-nitrogen heteronuclear Overhauser enhancement measurements revealed that the addition of a single monosaccharide unit at Thr-106 significantly slowed motions of the glycosylation loop on the nanosecond time scale. Subsequent addition of a Gal unit produced Gal(β1,3) GalNAcα[13C,15N]IFNα2a. This extension resulted in a further decrease in the dynamics of this loop. The methodology used here allowed the first such description of the structure and dynamics of an O-glycoprotein and opens the way to the study of this class of proteins. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.

Two new heteronuclear Nickel(II)/Sodium(I) complexes of a side-off compartmental Schiff base ligand were synthesized and characterized by spectroscopic methods. Crystal structures of both of the complexes were also obtained. The Schiff base ligand was synthesized from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with 2-hydroxy-3-methoxybenzaldehyde. In both of the complexes the Ni(II) ion is coordinated to the inner N 2 O 2 coordination sphere with square-planar geometry and the Na(I) ion is coordinated to the outer O 2 O 2 ′ coordination sphere. In Complex ( 1 ) with general formula [Ni(L)Na(CH 3 OH)(ClO 4 )] the sodium ion is seven coordinated while in ( 2 ) with general formula [{Ni(L)Na(OH 2 )} 2 (μ-Ni(CN) 4 )] the sodium ion is six coordinated. Intermolecular interactions in two studied complexes were analyzed using 3D Hirshfeld surfaces and corresponding 2D fingerprint plots. This analysis showed that the H … H and C … H/H … C contacts for both structures (altogether 67.5% of total Hirshfeld surface area for ( 1 ) and 77.6% for ( 2 )) and the O … H/H … O (24.2%) for ( 1 ) and the N … H/H … N (8.1%) contacts for ( 2 ) were the characteristic intermolecular contacts in the related crystal structures.

A new hetero trinuclear manganese(III)-iron(II) complex, [Mn(salen)(H 2 O)] 2 [Fe(CN) 6 ], in which salen is the dianionic form of N,N’-bis(5-methylsalicylidene)-1,2-diaminoethane, has been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of the complex is monoclinic: space group P 2 1 / c , a = 10.768(2), b = 14.248(3), c = 15.222(3) A, β = 95.394(2)o, V = 2325.0(8) A 3 , Z = 2, R 1 = 0.0754, wR 2 = 0.2366. The bis-Schiff base ligand coordinates to the Mn atom through phenolate O and imine N atoms. Each Mn atom in the complex is in octahedral coordination, with the equatorial donor atoms come from the Schiff base ligand, and with the axial donor atoms come from a water O atom and a cyanide N atom. The effects of the complex on the antimicrobial activity against Staphylococcus aureus , Escherichia coli , and Candida albicans were studied. KEY WORDS : Schiff base, Manganese(III) complex, Iron(II) complex, Heteronuclear, Crystal structure Bull. Chem. Soc. Ethiop. 2015 , 29(3), 407-413. DOI: http://dx.doi.org/10.4314/bcse.v29i3.8

[EN]: We report in this account on the controlled synthesis of novel d0-d8 early-late heteropolynuclear diolefin and carbonyl clusters. The synthetic approach was based on additive-deprotonation reactions involving the titanium and zirconium bis-hydrosulphido complexes of formula [Cp2Ti(SH)2] and [Cptt 2Zr(SH)2] and appropriate rhodium and iridium diolefin and carbonyl compounds. The significant differences between the resulting early-late complexes and their structures coming from the titanium or zirconium metalloligand precursors are highlighted. The catalytic activity of some representative titanium-rhodium and zirconium-rhodium compounds towards alkene hydroformylation was explored. Interestingly, the heterotetranuclear 'CpTi(μ3-S)3Rh3' structure was maintained as such under mild conditions., [FR]: Nous rapportons dans cet article la préparation contrôlée de nouveaux clusters hétéropolynucléaires early-late d0–d8 portant les ligands oléfine et carbonyle. La réaction de déprotonation–addition a été la méthode de synthèse utilisée et implique la condensation de complexes bis-hydrogénosulfure du titane et du zirconium, de formule [Cp2Ti(SH)2] et [Cptt2Zr(SH)2], sur les composés adéquats du rhodium et de l’iridium portant les ligands oléfine et carbonyle. Les différences significatives de structure entre les complexes early-late ainsi préparés, dues à la nature du métalloligand précurseur du titane ou du zirconium employé, sont mises en évidence. L’activité catalytique de quelques composés représentatifs titane–rhodium et zirconium–rhodium dans l’hydroformylation d’alcènes a été mesurée. Il convient de noter que la structure hétérotétranucléaire « CpTi(μ3-S)3Rh3 » est maintenue comme telle sous des conditions douces de réaction.

International audience; The discrimination and analysis of the NMR spectra of optically active molecules dissolvedin chiral liquid crystal solvents through 2D correlation experiments is studied. The techniqueallows the identification of the line positions of each enantiomer, thus providing a notablesimpliûcation of the spectral analysis. The 2D HOHAHA and multiple-quantum experimentsare investigated and discussed. The potential of the method is illustrated using a sample of( + ) 3,3,3-trichloroepoxypropane dissolved in a thermotropic cholesteric solvent. The case ofchiral molecules bearing a fluorine or deuterium nucleus has also been studied. In addition,it is shown that 2D heteronuclear correlation experiments are powerful methods for correlatingcarbon and proton spectral data of two enantiomers. A specific example is given through( * ) 2-bromopropanoic acid dissolved in a lyotropic polypeptide liquid crystal. Spectralparameters of each enantiomer are calculated for the different examples

Ionic liquids (ILs) composed of two different pyrazolium cations with dicyanamide and bis(trifluoromethanesulfonyl)imide anions have been synthesized and characterized by NMR, Kamlet-Taft solvatochromic parameters, conductivity and rheological measurements, as well as ab initio calculations. Density functional calculations for the two pyrazolium cations, 1-butyl-2-methylpyrazolium [brripz] and 1-butyl-2,3,5-trimethylpyrazolium [bm(3)pz], provide a full picture of their conformational states. Homo- and heteronuclear NOE show aggregation motives sensitive to steric hindrance and the anions' nature. Self-diffusion coefficients D for the anion and the cation have been measured by pulsed field gradient spin echo NMR (PGSE-NMR). The ionic diffusivity is influenced by their chemical structure and steric hindrance, giving the order D-cation > D-anion. for all of the examined compounds. The measured ion diffusion coefficients, viscosities, and ionic conductivity follow the Vogel-Fulcher-Tammann (VFT) equation for the temperature dependencies, and the best-fit parameters have been determined. Solvatochromic parameters indicate an increased ion association upon going from bis(trifluoromethanesulfonyl)imide to dicyanamide-based pyrazolium salts, as well as specific hydrogen bond donor capability of H atoms on the pyrazolium ring. All of these physical properties are compared to those of an analogous series of imidazolium-based ILs.

We present a detailed analysis of the production efficiency of weakly bound heteronuclear KRb-Feshbach molecules using radio frequency association in a harmonic trap. The efficiency was measured in a wide range of temperatures, binding energies and radio frequencies. A comprehensive analytical model is presented, explaining the observed asymmetric spectra and achieving good quantitative agreement with the measured production rates. This model provides a deep understanding of the molecule association process and paves the way for future experiments which rely on Feshbach molecules e.g. for the production of deeply bound molecules., Comment: 5 pages, 4 figures

The cytochromes c′ are paramagnetic heme proteins generally consisting of two identical 14 kDa subunits. The recent assignment of the 'H and15N resonances of the Rhodobacter capsulatus ferricytochrome c' has allowed characterization of the dynamic properties by measurement of the heteronuclear NOE for each resolved amide group. The relative importance of fast local motion and paramagnetic effect on nuclear relaxation were distinguished by comparison of the measured heteronuclear NOE with that of the overall experimental average. We show that the average experimental value of -0.16 corresponds to the rigid body motion expected for a spherical complex of 28 kDa. Residues 3–5, 50–55 and 69–70 exhibit decreased heteronuclear NOE due to local motions on a fast time scale with respect to molecular tumbling. Based on the X-ray crystal structure of the homologous cytochrome c′ from Chromatium vinosum, the mobile regions correspond to the N-terminus of helix-1 and 2 regions of nonregular secondary structure located between helices-2 and -3.

The capsular polysaccharide of Actinobacillus pleuropneumoniae serotype 5b (strain L20) was found to be a high molecular mass polymer composed of 2-acetamido-2-deoxy-D-glucose, D-glucose, and 3-deoxy-D-manno-octulosonic acid (KDO). Methylation analysis, partial hydrolysis and a combination of homonuclear and 1H-detected heteronuclear shift-correlated nuclear magnetic resonance experiments showed the polysaccharide to be a branched polymer of a trisaccharide repeating unit, having the structure: [formula; see text]

A method for the quantitative determination of interproton distances from H-1 NOE relayed heteronuclear correlation is presented. Model compounds are investigated. Accurate distances are obtained if all the factors affecting such distance measurements, such as the local mobility and the presence of strong coupling in heteronuclear systems, are properly taken into account.