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101.
Alexey Marchuk Florian J. Pucher Friedrich W. Karau Prof. Dr. Wolfgang Schnick 《Angewandte Chemie (International ed. in English)》2014,53(9):2469-2472
Phosphorus nitride imide, PN(NH), is of great scientific importance because it is isosteric with silica (SiO2). Accordingly, a varied structural diversity could be expected. However, only one polymorph of PN(NH) has been reported thus far. Herein, we report on the synthesis and structural investigation of the first high‐pressure polymorph of phosphorus nitride imide, β‐PN(NH); the compound has been synthesized using the multianvil technique. By adding catalytic amounts of NH4Cl as a mineralizer, it became possible to grow single crystals of β‐PN(NH), which allowed the first complete structural elucidation of a highly condensed phosphorus nitride from single‐crystal X‐ray diffraction data. The structure was confirmed by FTIR and 31P and 1H solid‐state NMR spectroscopy. We are confident that high‐pressure/high‐temperature reactions could lead to new polymorphs of PN(NH) containing five‐fold‐ or even six‐fold‐coordinated phosphorus atoms and thus rivalling or even surpassing the structural variety of SiO2. 相似文献
102.
103.
Cover Picture: Absolute Configuration from Different Multifragmentation Pathways in Light‐Induced Coulomb Explosion Imaging (ChemPhysChem 16/2016) 下载免费PDF全文
Dr. Martin Pitzer Gregor Kastirke Dr. Maksim Kunitski Dr. Till Jahnke Dr. Tobias Bauer Christoph Goihl Florian Trinter Carl Schober Kevin Henrichs Jasper Becht Stefan Zeller Helena Gassert Markus Waitz Andreas Kuhlins Hendrik Sann Felix Sturm Florian Wiegandt Dr. Robert Wallauer Dr. Lothar Ph. H. Schmidt Allan S. Johnson Manuel Mazenauer Benjamin Spenger Sabrina Marquardt Sebastian Marquardt Prof. Dr. Horst Schmidt‐Böcking Prof. Dr. Jürgen Stohner Prof. Dr. Reinhard Dörner Dr. Markus Schöffler Prof. Dr. Robert Berger 《Chemphyschem》2016,17(16):2448-2448
104.
Matthias Bruch Dietmar Mder Florian Bauers Ton Loontjens Rolf Mülhaupt 《Journal of polymer science. Part A, Polymer chemistry》2000,38(8):1222-1231
Various copolyesteramides were prepared by melt compounding at 220 °C involving reaction of poly(styrene‐co‐maleic anhydride), SMA, with 6, 17, and 28 wt % maleic anhydride content, and 1‐dodecanol, C12OH, in the presence of 2‐undecyl‐1,3‐oxazoline, C11OXA. Copolymer architectures were examined by means of 1H NMR, FTIR, DSC, and TGA using model compounds prepared via solution reactions. While conversion of anhydride with alcohol was poor due to the thermodynamically favored anhydride ring formation, very high conversions were achieved when stoichiometric amounts of C11OXA were added. According to spectroscopic studies esteramide groups resulted from reaction of oxazoline with carboxylic acid intermediate. In the absence of alcohol, C11OXA reacted with anhydride to produce esterimides. Effective attachment of flexible n‐alkyl side chains via simultaneous reaction of C12OH and C11OXA resulted in lower glass‐transition temperatures of copolyesteramides. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1222–1231, 2000 相似文献
105.
Berger I Hanif M Nazarov AA Hartinger CG John RO Kuznetsov ML Groessl M Schmitt F Zava O Biba F Arion VB Galanski M Jakupec MA Juillerat-Jeanneret L Dyson PJ Keppler BK 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(29):9046-9057
The synthesis and in vitro anticancer activity of dihalogenido(eta6-p-cymene)(3,5,6-bicyclophosphite-alpha-D-glucofuranoside)ruthenium(II) complexes are described. The compounds were characterized by NMR spectroscopy and ESI mass spectrometry, and the molecular structures of dichlorido-, dibromido- and diiodido(eta6-p-cymene)(3,5,6-bicyclophosphite-1,2-O-isopropylidene-alpha-D-glucofuranoside)ruthenium(II) were determined by X-ray diffraction analysis. The complexes were shown to undergo aquation of the first halido ligand in aqueous solution, followed by hydrolysis of a P--O bond of the phosphite ligand, and finally formation of dinuclear species. The hydrolysis mechanism was confirmed by DFT calculations. The aquation of the complexes was markedly suppressed in 100 mM NaCl solution, and notably only very slow hydrolysis of the P--O bond was observed. The complexes showed affinity towards albumin and transferrin and monoadduct formation with 9-ethylguanine. In vitro studies revealed that the 3,5,6-bicyclophosphite-1,2-O-cyclohexylidene-alpha-D-glucofuranoside complex is the most cytotoxic compound in human cancer cell lines (IC50 values from 30 to 300 microM depending on the cell line). 相似文献
106.
Oberstrass FC Allain FH Ravindranathan S 《Journal of the American Chemical Society》2008,130(36):12007-12020
RNA recognition by proteins is often accompanied by significant changes in RNA dynamics in addition to conformational changes. However, there are very few studies which characterize the changes in molecular motions in RNA on protein binding. We present a quantitative (13)C NMR relaxation study of the changes in RNA dynamics in the pico-nanosecond time scale and micro-millisecond time scale resulting from interaction of the stem-loop SRE-RNA with the VTS1p-SAM domain. (13)C relaxation rates of the protonated carbons of the nucleotide base and anomeric carbons have been analyzed by employing the model-free formalism, for a fully (13)C/(15)N-labeled sample of the SRE-RNA in the free and protein-bound forms. In the free RNA, the nature of molecular motions are found to be distinctly different in the stem and the loop region. On binding to the protein, the nature of motions becomes more homogeneous throughout the RNA, with many residues showing increased flexibility at the aromatic carbon sites, while the anomeric carbon sites become more rigid. Surprisingly, we also observe indications of a slow collective motion of the RNA in the binding pocket of the protein. The observation of increased motions on binding is interesting in the context of growing evidence that binding does not always lead to motional restrictions and the resulting entropy gain could favor the free energy of association. 相似文献
107.
108.
David Schnieders Adrienne Hammerschmidt Michael Merkel Florian Schweppe Bernt Krebs Prof. Dr. 《无机化学与普通化学杂志》2008,634(15):2933-2939
Starting from the tripodal tetradentate ligands ‐(3,5‐dibromo‐2‐hydroxybenzyl)(2‐hydroxybenzyl)(2‐pyridyl)methylamine (H2L1), (3,5‐dibromo‐2‐hydroxybenzyl)(2‐hydroxy‐5‐nitrobenzyl)(2‐pyridyl)methylamine (H2L2), and (3,5‐dichloro2‐hydroxybenzyl)(2‐hydroxy‐5‐nitrobenzyl)(2‐pyridyl)methylamine (H2L3) the new isostructural dinuclear zinc compounds [Zn2(L1)2]·N(CH2CH3)3 ( 1 ), [Zn2(L2)2]·2CH3OH ( 2 ) and [Zn2(L3)2]·C4H10O ( 3 ) were synthesized. Due to their enzyme‐like trigonal bipyramidal N2O3 coordination environment of the zinc ions and the similar Zn···Zn distances the complexes can be considered to be structural models for the active sites in phospholipase C and nuclease P1. With H2L3 also the dinuclear complex [Co2(L2)2(CH3OH)]·2CH3OH·0.5C4H10O ( 4 ) could be prepared. The new compounds were isolated and characterized by single crystal X‐ray crystallography as well as infrared spectroscopy. The cobalt compound 4 was additionally characterized by UV‐Vis spectroscopy and magnetic measurements. 1 crystallizes in the monoclinic space group P21/n with a = 11.2814(2), b = 28.6154(2), c = 13.1866(3) Å, β = 96.995(1)°, V = 4225.2(2) Å3, Z = 4. 2 and 3 are monoclinic, space group C2/c with a = 23.084(5), b = 9.232(2), c = 21.849(4) Å, &β; = 96.83(3)°, V = 4623(2) Å3, Z = 4, and a = 22.7834(3), b = 9.2463(1), c = 21.6351(3) Å, &β; = 97.592(1)°, V = 4517.7(2) Å3, Z = 4, respectively. 4 crystallizes in the monoclinic space group I2/a with a = 22.4680(4), b = 20.5517(4), c = 22.8910(6) Å, &β; = 111.938(1)°, V = 9804.7(4) Å3, Z = 8. 4 shows an effective magnetic moment of 6.72 μB at 300 K which clearly indicates the presence of two cobalt(II) high spin ions with Curie‐Weiss behaviour above 80 K. At lower temperatures a decrease of the effective magnetic moment was observed. 相似文献
109.
Ina Heckelmann Zifei Lu Dr. Joseph C. A. Prentice Dr. Florian Auras Dr. Tanya K. Ronson Prof. Dr. Richard H. Friend Prof. Dr. Jonathan R. Nitschke Dr. Sascha Feldmann 《Angewandte Chemie (International ed. in English)》2023,62(12):e202301806
Organic semiconductors are promising for efficient, printable optoelectronics. However, strong excited-state quenching due to uncontrolled aggregation limits their use in devices. We report on the self-assembly of a supramolecular pseudo-cube formed from six perylene diimides (PDIs). The rigid, shape-persistent cage sets the distance and orientation of the PDIs and suppresses intramolecular rotations and vibrations, leading to non-aggregated, monomer-like properties in solution and the solid state, in contrast to the fast fluorescence quenching in the free ligand. The stabilized excited state and electronic purity in the cage enables the observation of delayed fluorescence due to a bright excited multimer, acting as excited-state reservoir in a rare case of benign inter-chromophore interactions in the cage. We show that self-assembly provides a powerful tool for retaining and controlling the electronic properties of chromophores, and to bring molecular electronics devices within reach. 相似文献
110.
Patrick H. Maag Dr. Florian Feist Dr. Vinh X. Truong Dr. Hendrik Frisch Prof. Peter W. Roesky Prof. Christopher Barner-Kowollik 《Angewandte Chemie (International ed. in English)》2023,62(37):e202309259
We introduce a class of single-chain nanoparticles (SCNPs) that respond to visible light (λmax=415 nm) with complete unfolding from their compact structure into linear chain analogues. The initial folding is achieved by a simple esterification reaction of the polymer backbone constituted of acrylic acid and polyethylene glycol carrying monomer units, introducing bimane moieties, which allow for the photochemical unfolding, reversing the ester-bond formation. The compaction and the light driven unfolding proceed cleanly and are readily followed by size exclusion chromatography (SEC) and diffusion ordered NMR spectroscopy (DOSY), monitoring the change in the hydrodynamic radius (RH). Importantly, the folding reaction and the light-induced unfolding are reversible, supported by the high conversion of the photo cleavage. As the unfolding reaction occurs in aqueous systems, the system holds promise for controlling the unfolding of SCNPs in biological environments. 相似文献