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101.
Karolina Szamota-Leandersson Mats Leandersson Pål Palmgren Mats Göthelid Ulf O. Karlsson 《Surface science》2009,603(1):190-196
Deposition of Bi onto (4 × 2)/c(8 × 2)-InAs(1 0 0) and subsequent annealing results in a (2 × 6) surface reconstruction as seen by low electron energy diffraction. The Bi condensation eliminates the original (4 × 2) surface reconstruction and creates a new structure including Bi-dimers. This surface is metallic and hosts a charge accumulation layer seen through photoemission intensity near the Fermi level. The accumulation layer is located in the bulk region below the surface, but the intensity of the Fermi level structure is strongly dependent on the surface order. 相似文献
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Ewa Kita Emilia Kiersikowska Hasan Marai Karolina Mierkiewicz 《Transition Metal Chemistry》2014,39(1):63-70
A potential synthetic biochromium source, bis-aspartatochromium(III) ion (where Asp is a tridentate N,O,O′-ligand, bonded via amine nitrogen and carboxylate oxygen atoms) has been obtained and characterized in aqueous solution. Kinetics of partial dechelation of the complex catalysed by H+ and OH? ions has been studied spectrophotometrically within 0.1–1.0 M HClO4 and 0.1–1.0 M NaOH ranges under first-order conditions. A linear dependence of the k obs,H on [H+] and independence of the k obs,OH on [OH?] were established. The derived rate expression and identification of components of the reaction mixture provide evidence for a reaction mechanism, where the key role in the overall process is the formation of an intermediate species with bidentate N,O-bonded Asp via both spontaneous and H+(OH?)-catalysed reaction paths. The intermediate is meta-stable and at pH 5–7 restores the substrate. 相似文献
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Self‐Assembling Hydrogels Crosslinked Solely by Receptor–Ligand Interactions: Tunability,Rationalization of Physical Properties,and 3D Cell Culture 下载免费PDF全文
Michael S. Thompson Dr. Mikhail V. Tsurkan Dr. Karolina Chwalek Prof. Martin Bornhauser Dr. Michael Schlierf Prof. Carsten Werner Dr. Yixin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3178-3182
We report a novel, noncovalent hydrogel system crosslinked solely by receptor–ligand interactions between biotin and avidin. The simple hydrogel synthesis and functionalization together with the widespread use of biotinylated ligands in biosciences make this versatile system suitable for many applications. The gels possess a range of tunable physical properties, including stiffness, lifetime, and swelling. The erosion rates, unexpectedly fast compared to the kinetic parameters for biotin–avidin, are explored in terms of stretching tensions on the polymers, a concept well‐known on the single‐molecule level, but largely unexplored in supramolecular systems. As proof of utility, the gels were functionalized with different peptide sequences to control human mesenchymal stromal cell morphology in 3D culture. 相似文献
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Dipl.‐Chem. Michael Daub Dr. Karolina Kazmierczak Prof. Dr. Henning A. Höppe Prof. Dr. Harald Hillebrecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):16954-16962
The structural principles of borosulfates derived from the B/S ratio are confirmed and extended to new representatives of this class showing novel motifs. According to the composition, Na[B(S2O7)2] (P21/c; a=10.949(6), b=8.491(14), c=12.701(8) Å; β=110.227(1)°; Z=4) and K[B(S2O7)2] (Cc; a=11.3368(6), b=14.662(14), c=13.6650(8) Å; β=94.235(1)°; Z=8) contain isolated [B(S2O7)2]? ions, in which the central BO4 tetrahedron is coordinated by two disulfate units. The alkali cations have coordination numbers of 7 (Na) and 8 (K), respectively. The structure of Cs[B(S2O7)(SO4)] (P21/c; a=10.4525(6), b=11.3191(14), c=8.2760(8) Å; β=103.206(1); Z=4) combines, for the first time, sulfate and disulfate units into a chain structure. Cs has a coordination number of 12. The same structural units were found in H[B(S2O7)(SO4)] (P21/c; a=15.6974(6), b=11.4362(14), c=8.5557(8) Å; β=90.334(3)°; Z=8). This compound represents the first example of a polyacid. The hydrogen atoms were located and connect the chains to form layers through hydrogen‐bonding bridges. H3O[B(SO4)2] (P4/ncc; a=9.1377(6), c=7.3423(8) Å; Z=4) is the first oxonium compound of this type to be found. The BO4 tetrahedra are linked by SO4 tetrahedra to form linear chains similar to those in SiS2. The chains form a tetragonal rod packing structure with H3O+ between the rods. The structures of borosulfates can be classified following the concept described by Liebau for silicates, which was extended to borophosphates by Kniep et al. In contrast to these structures, borosulfates do not comprise B‐O‐B bonds but instead contain S‐O‐S connections. All compounds were obtained as colourless, moisture‐sensitive single crystals by reaction of B2O3 and the appropriate alkali salt in oleum. 相似文献
110.
Micha Magott Bartomiej Gawe Marcin Sarewicz Mateusz Reczyski Karolina Ogorzay Wacaw Makowski Dawid Pinkowicz 《Chemical science》2021,12(26):9176
While metal–organic frameworks (MOFs) are at the forefront of cutting-edge porous materials, extraordinary sorption properties can also be observed in Prussian Blue Analogs (PBAs) and related materials comprising extremely short bridging ligands. Herein, we present a bimetallic nonporous cyanide-bridged coordination polymer (CP) {[Mn(imH)]2[Mo(CN)8]}n (1Mn; imH = imidazole) that can efficiently and reversibly capture and release water molecules over tens of cycles without any fatigue despite being based on one of the shortest bridging ligands known – the cyanide. The sorption performance of {[Mn(imH)]2[Mo(CN)8]}n matches or even outperforms MOFs that are typically selected for water harvesting applications with perfect sorption reversibility and very low desorption temperatures. Water sorption in 1Mn is possible due to the breathing effect (accompanied by a dramatic cyanide-framework transformation) occurring in three well-defined steps between four different crystal phases studied structurally by X-ray diffraction structural analysis. Moreover, the capture of H2O by 1Mn switches the EPR signal intensity of the MnII centres, which has been demonstrated by in situ EPR measurements and enables monitoring of the hydration level of 1Mn by EPR. The sorption of water in 1Mn controls also its photomagnetic behavior at the cryogenic regime, thanks to the presence of the [MoIV(CN)8]4− photomagnetic chromophore in the structure. These observations demonstrate the extraordinary sorption potential of cyanide-bridged CPs and the possibility to merge it with the unique physical properties of this class of compounds arising from their bimetallic character (e.g. photomagnetism and long-range magnetic ordering).A cyanide-bridged coordination polymer {[Mn(imH)]2[Mo(CN)8]}n shows exceptional water sorption properties, very large breathing effect and outstanding stability – properties that are unique for this class of compounds – Prussian blue analogs. 相似文献