Search results for "Lysis"
showing 10 items of 34769 documents
Young Chemists: A Source of New Ideas
2018
Young again: A second edition of this special issue has been assembled to honor both the recent participants of the European Young Chemist Award (EYCA) as well as young and emerging scientists from around the world.
A Ferroelectric Iron(II) Spin Crossover Material
2017
A dual-function material in which ferroelectricity and spin crossover coexist in the same temperature range has been obtained. Our synthetic strategy allows the construction of acentric crystal structures in a predictable way and is based on the high directionality of hydrogen bonds. The well-known iron(II) spin crossover complex [Fe(bpp)₂]²+ (bpp = 2,6-bis(pyrazol-3-yl)pyridine), a four-fold noncentrosymmetric H-bond donor, was combined with a disymmetric H-bond acceptor such as the isonicotinate (isonic) anion to afford [Fe(bpp)₂](isonic)₂·2H₂O. This low-spin iron(II) compound crystallises in the acentric nonpolar I-4 space group and shows piezoelectricity and SHG properties. Upon dehydra…
Structural Tuning and Conformational Stability of Aromatic Oligoamide Foldamers
2017
A series of aromatic oligoamide foldamers with two or three pyridine-2,6-dicarboxamide units as their main folding motifs and varying aromatic building blocks as linkers have been synthetized to study the effects of the structural variation on the folding properties and conformational stability. Crystallographic studies showed that in the solid state the central linker unit either elongates the helices and more open S-shaped conformations, compresses the helices to more compact conformations or acts as a rigid spacer separating the pyridine-2,6-dicarboxamide units, which for their part add the predictability of the conformational properties. Multidimensional NMR studies showed that, even in…
Cover Picture: Selective Synthesis of Partially Protected Nonsymmetric Biphenols by Reagent‐ and Metal‐Free Anodic Cross‐Coupling Reaction (Angew. Ch…
2016
N,N′-Disubstituted Indigos as Readily Available Red-Light Photoswitches with Tunable Thermal Half-Lives
2017
Some rare indigo derivatives have been known for a long time to be photochromic upon irradiation with red light, which should be advantageous for many applications. However, the absence of strategies to tune their thermal half-lives by modular molecular design as well as the lack of proper synthetic methods to prepare a variety of such molecules from the parent indigo dye have so far precluded their use. In this work, several synthetic protocols for N-functionalization have been developed, and a variety of N-alkyl and N-aryl indigo derivatives have been prepared. By installation of electron-withdrawing substituents on the N-aryl moieties, the thermal stability of the Z-isomers could be enha…
Hybrid Molecular Materials Based upon Magnetic Polyoxometalates and Organic π-Electron Donors: Syntheses, Structures, and Properties of Bis(ethylene…
1998
International audience; The syntheses, crystal structures, and physical properties of the series of radical salts made with bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) and monosubstituted α-Keggin polyoxoanions of formula [XZ(H2O)M11O39]5- (XZM11 = Si(IV)Fe(III)Mo11, Si(IV)Cr(III)W11, P(V)Con(II)W11, P(V)Ni(II)W11, P(V)Cu(II)W11 P(V)Zn(II)W11, P(V)Mn(II)W11, and P(V)Mn(II)Mo11) containing a magnetic metal ion Z on a peripheral octahedral site of the Keggin union are reported. They all crystallize in two related series called α2 and α3. The general structure consists of alternating layers of the organic donor and the Keggin polyoxometalates. While the stoichiometry and α-packing a…
A decacobalt(ii) cluster with triple-sandwich structure obtained by partial reductive hydrolysis of a pentacobalt(ii/iii) Weakley-type polyoxometalat…
2016
Partial reductive hydrolysis of a penta-CoII/III cluster [CoII4(H2O)2(CoIIIW9O34)(PW9O34)]12− (1) leads to the formation of [Co2{Co3(H2O)(Co(OH)2W7O26)(PW9O34)}2]22− (2). This polyoxometalate is made up of two capping [PW9O34]9− units and two bridging [W7O26]10− units that assemble to encapsulate a novel deca-CoII cluster core comprising octahedral and tetrahedral CoII ions.
Electrochemical instability of highly fluorinated tetraphenyl borates and syntheses of their respective biphenyls
2018
Highly fluorinated tetraphenyl borate anions are of importance as weakly coordinating anions in metalorganic reactions. However, at high positive potentials their electrochemical stability in organic solvents is not sufficient. This was investigated by a comprehensive cyclic voltammetry study and can be used synthetically to generate highly fluorinated biphenyls.
Localization of alkali metal ions in sodium-promoted palladium catalysts as studied by low energy ion scattering and transmission electron microscopy
1996
Three series of palladium-based catalysts have been studied by Low Energy Ion Scattering (LEIS) and Transmission Electron Microscopy (TEM). The first series is comprised of Na-Pd/SiO{sub 2} catalysts, obtained by addition of palladium to a silica support and by further addition of sodium ions with a Na/Pd atomic ratio (R) equal to 0,6.4 and 25.6. The second series consists of palladium catalysts supported on natural pumice, in which, due to a different loading of supported palladium, R{prime}, the (Na+K)/Pd atomic ratio, is equal to 17.0 and 39.4. The third series is represented by two palladium-based catalysts supported on {open_quotes}model pumices,{close_quotes} synthetic silico-aluminat…
Electrostatic complementarity in pseudoreceptor modeling based on drug molecule crystal structures: the case of loxistatin acid (E64c)
2015
After a long history of use as a prototype cysteine protease inhibitor, the crystal structure of loxistatin acid (E64c) is finally determined experimentally using intense synchrotron radiation, providing insight into how the inherent electronic nature of this protease inhibitor molecule determines its biochemical activity. Based on the striking similarity of its intermolecular interactions with those observed in a biological environment, the electrostatic potential of crystalline E64c is used to map the characteristics of a pseudo-enzyme pocket.