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91.
Alexander Hübner Daniel Strobusch Hans-Wolfram Lerner Michael Bolte 《Journal of chemical crystallography》2008,38(12):953-957
Abstract The crystal structure of the title compound, C30H42O12Zn3, originally determined from untwinned crystals (Bennett et al. Acta Cryst B 24:904, 1968) has been redetermined from twinned
crystals. The effect of the twinning is that additional reflections appear in the diffraction pattern leading to a unit cell
with a too long c-axis in which the structure cannot be solved. Thus, for a successful structure solution the correct unit cell has to be found
and for refinement the twinning has to be taken into account. The central Zn atom is located on a twofold rotation axis. It
is hexacoordinated in a distorted octahedral mode, whereas the coordination geometry of the two terminal Zn atoms is distorted
trigonal bipyramidal.
Index Abstract The crystal structure of the title compound, Zinc(II) acetylacetonate trimer, has been redetermined from twinned crystals.
For a successful structure solution the correct unit cell had to be found and for refinement the twinning had to be taken
into account. The central Zn atom is located on a twofold rotation axis. It is hexacoordinated in a distorted octahedral mode,
whereas the coordination geometry of the two terminal Zn atoms is distorted trigonal bipyramidal.
An erratum to this article can be found at 相似文献
92.
Tanja Kaehler Michael Bolte Hans‐Wolfram Lerner Matthias Wagner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(33):11501-11506
Substitutional doping of perylene with two boron atoms at the 6b/12b positions and two oxygen or nitrogen atoms at the 1/7 positions has been achieved. The modular synthesis route developed for these bis‐BO‐ ( 3 ) and bis‐BN‐perylenes ( 5 ) starts from the readily accessible borinic acid derivative of the doubly brominated 9,10‐dihydro‐9,10‐diboraanthracene (DBA), 1,5‐Br2DBA(OH)2. A Stille‐type reaction first furnishes the alkynyl‐substituted species 1,5‐(RCC)2DBA(OH)2 ( 2 ), which undergo double ring closure to afford 3 via the gold‐catalyzed addition of the O?H bonds to the C≡C bonds. Treatment of 2 with MeN(SiMe3)2 leads to aminoborane intermediates 1,5‐(RCC)2DBA(N(H)Me)2, which can be ring‐closed to give 5 in a similar manner as in the case of 3 . Different substituents R (such as Me, tBuPh) can be introduced at the 2/8 positions of the perylene core. The products obtained undergo reversible reduction and are efficient blue/turquoise emitters. 相似文献
93.
We suggest to use "fluctuation spectroscopy" as a method to detect granularity in a disordered metal close to a superconducting transition. We show that with lowering temperature T the resistance R(T) of a system of relatively large grains initially grows due to the fluctuation suppression of the one-electron tunneling but decreases with further lowering T due to the coherent charge transfer of the fluctuation Cooper pairs. Under certain conditions, such a maximum in R(T) turns out to be sensitive to weak magnetic fields due to a novel Maki-Thompson-type mechanism. 相似文献
94.
Günter Margraf Michael Bolte Matthias Wagner Hans-Wolfram Lerner 《Journal of chemical crystallography》2007,37(7):503-506
The mixed-valence compound [Li(THF)4]Cu2Br4 was synthesized in a redox reaction from 1,4-dihydroxynaphthalene, CuBr2 and LiNtBuSiMe3 in THF. X-ray quality crystals of [Li(THF)4]Cu2Br4 (monoclinic, P21/c) are obtained from the mother liquor at ambient temperature. In the solid state, infinite chains of anionic [Cu2Br4]− units are established. These chains are separated by [Li(THF)4]+ cations. 相似文献
95.
Lerner HW Sänger I Schödel F Lorbach A Bolte M Wagner M 《Dalton transactions (Cambridge, England : 2003)》2008,(6):787-792
The caesium triphosphenide Cs[tBu3SiPPPSitBu3] was accessible from the reaction of CsF with the sodium triphosphenide Na[tBu3SiPPPSitBu3] in tetrahydrofuran at room temperature. In contrast to the preparation of tetrahydrofuran-solvated silanides M[SitBu3] (M = Li, Na, K), our efforts to synthesize the caesium silanide Cs[SitBu3] as a tetrahydrofuran complex failed. When tBu3SiBr was treated with an excess of caesium metal in tetrahydrofuran at room temperature, the caesium enolate Cs[OCH=CH2] and the supersilane tBu3SiH formed rather than the silanide Cs[SitBu3]. X-Ray quality crystals of the enolate Cs[OCH=CH2] (orthorhombic, Pnma) were obtained from tetrahydrofuran at ambient temperature. In contrast to the structures of its homologues M[tBu3SiPPPSitBu3] (M = Na, K), the caesium triphosphenide Cs[tBu3SiPPPSitBu3] features a polymer in the solid state (orthorhombic, Cmcm). 相似文献
96.
Anahí Sanluis-Verdes Ana Peñaherrera José L. Torán Gustavo Rosero María A. Noriega Betiana Lerner Maximiliano Pérez José M. Casasnovas 《Electrophoresis》2023,44(9-10):864-872
A method development aimed for high-throughput and automated antibody screening holds great potential for areas ranging from fundamental molecular interactions to the discovery of novel disease markers, therapeutic targets, and monoclonal antibody engineering. Surface display techniques enable efficient manipulation of large molecular libraries in small volumes. Specifically, phage display appeared as a powerful technology for selecting peptides and proteins with enhanced, target-specific binding affinities. Here, we present a phage-selection microfluidic device wherein electrophoresis was performed under two orthogonal electric fields through an agarose gel functionalized with the respective antigen. This microdevice was capable of screening and sorting in a single round high-affinity phage-displayed antibodies against virus glycoproteins, including human immunodeficiency virus-1 glycoprotein 120 or the Ebola virus glycoprotein (EBOV-GP). Phages were differentially and laterally swept depending on their antigen affinity; the high-affinity phages were recovered at channels proximal to the application site, whereas low-affinity phages migrated distal after electrophoresis. These experiments proved that the microfluidic device specifically designed for phage-selection is rapid, sensitive, and effective. Therefore, this is an efficient and cost-effective method that allowed highly controlled assay conditions for isolating and sorting high-affinity ligands displayed in phages. 相似文献
97.
Scheuermann S Kretz T Vitze H Bats JW Bolte M Lerner HW Wagner M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(8):2590-2601
The synthesis, structural characterisation and coordination behaviour of mono- and ditopic p-hydroquinone-based bis(pyrazol-1-yl)methane ligands is described (i.e., 2-(pz2CH)C6H3(OH)2 (2a), 2-(pz2CH)-6-(tBu)C6H2(OH)2 (2b), 2-(pz2CH)-6-(tBu)C6H2(OSiiPr3)(OH) (2c), 2,5-(pz2CH)2C6H2(OH)2 (4)). Ligands 2a, 2b and 4 can be oxidised to their p-benzoquinone state on a preparative scale (2a ox, 2b ox, 4 ox). An octahedral Ni II complex [trans-Ni(2c)2] and square-planar Pd II complexes [Pd2bCl2] and [Pd2b ox Cl2] have been prepared. In the two Pd II species, the ligands are coordinated only through their pyrazolyl rings. The fact that [Pd2bC12] and [Pd2b oxC12] are isolable compounds proves that redox transitions involving the p-quinone substituent are fully reversible. In [Pd2b oxCl2], the methine proton is highly acidic and can be abstracted with bases as weak as NEt(3). The resulting anion dimerises to give a dinuclear macrocyclic Pd II complex, which has been structurally characterised. The methylated ligand 2-(pz2CMe)C6H3O2 (11 ox) and its Pd II complex [Pd11 oxCl2] are base-stable. A new class of redox-active ligands is now available with the potential for applications both in catalysis and in materials science. 相似文献
98.
A Highly Reactive Geminal P/B Frustrated Lewis Pair: Expanding the Scope to C−X (X=Cl,Br) Bond Activation 下载免费PDF全文
Kamil Samigullin Isabelle Georg Dr. Michael Bolte Dr. Hans‐Wolfram Lerner Prof. Dr. Matthias Wagner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3478-3484
The geminal frustrated Lewis pair tBu2PCH2B(Fxyl)2 ( 1 ; Fxyl=3,5‐(CF3)2C6H3) is accessible in 65 % yield from tBu2PCH2Li and (Fxyl)2BF. According to NMR spectroscopy and X‐ray crystallography, 1 is monomeric both in solution and in the solid state. The intramolecular P ??? B distance of 2.900(5) Å and the full planarity of the borane site exclude any significant P/B interaction. Compound 1 readily activates a broad variety of substrates including H2, EtMe2SiH, CO2/CS2, Ph2CO, and H3CCN. Terminal alkynes react with heterolysis of the C?H bond. Haloboranes give cyclic adducts with strong P?BX3 and weak R3B?X bonds. Unprecedented transformations leading to zwitterionic XP/BCX3 adducts occur on treatment of 1 with CCl4 or CBr4 in Et2O. In less polar solvents (C6H6, n‐pentane), XP/BCX3 adduct formation is accompanied by the generation of significant amounts of XP/BX adducts. FLP 1 catalyzes the hydrogenation of PhCH=NtBu and the hydrosilylation of Ph2CO with EtMe2SiH. 相似文献
99.
While performing biomolecular interaction analysis (BIA), scientistsoften use surface plasmon resonance (SPR) to measure rate constantsof the associated reactions. A mathematical model of a BIAcoreTM,a common SPR device, consists of a convection-diffusion equationin a channel with a reacting surface at the channel ceiling.Asymptotic and singular perturbation techniques are used toanalyse the concentration of the reacting species in two cases:when the reaction occurs much more slowly than diffusion, andwhen the reaction occurs on the same time-scale as diffusion.Linear and nonlinear integral equations result from the analysis;explicit and asymptotic solutions are constructed for physicallyrealizable cases. These expressions provide a direct way toestimate the rate constants from raw data. 相似文献