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排序方式: 共有959条查询结果,搜索用时 15 毫秒
951.
Gerhard Wegner Pia Baum Maren Müller Jochen Norwig Katharina Landfester 《Macromolecular Symposia》2001,175(1):349-356
Water soluble graft polymers prepared by copolymerization of either methacrylic acid (MAA) or vinylsulfonic acid (VS) with α‐methoxy‐ω‐methacroyl‐oligo(oxyethylene)s (PEOn‐MA) serve to control nucleation and crystal growth during precipitation of inorganic crystals from aqueous media. Precipitation of zinc oxide crystals (‘zincite’) is used as example for such mineralization processes. Homogeneous and narrow crystal size distributions are obtained in presence of ppm‐amounts of graft copolymers. Copolymer is incorporated into the crystals demonstrated by using latex particles with ‐CO2H‐group rich surfaces as controlling additives. Incorporation of these particles leads to single crystals with pores of the size of the particles (‘Swiss cheese’ morphologies). 相似文献
952.
Dr. Raju Bej Dr. Chuanxiong Nie Dr. Kai Ludwig Dr. Vahid Ahmadi Dr. Jakob Trimpert Julia M. Adler Dr. Tatyana L. Povolotsky Dr. Katharina Achazi Marten Kagelmacher Ricardo Martin Vidal Dr. Jens Dernedde Dr. Benedikt B. Kaufer Prof. Dr. Rainer Haag 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304010
Mucins are the key component of the defensive mucus barrier. They are extended fibers of very high molecular weight with diverse biological functions depending strongly on their specific structural parameters. Here, we present a mucin-inspired nanostructure, produced via a synthetic methodology to prepare methacrylate-based dendronized polysulfates ( MIP-1 ) on a multi gram-scale with high molecular weight (MW=450 kDa) and thiol end-functionalized mucin-inspired polymer ( MIP ) via RAFT polymerization. Cryo-electron tomography (Cryo-ET) analysis of MIP-1 confirmed a mucin-mimetic wormlike single-chain fiber structure (length=144±59 nm) in aqueous solution. This biocompatible fiber showed promising activity against SARS-CoV-2 and its mutant strain, with a remarkable low half maximal (IC50) inhibitory concentration (IC50=10.0 nM). Additionally, we investigate the impact of fiber length on SARS-CoV-2 inhibition by testing other functional polymers ( MIPs ) of varying fiber lengths. 相似文献
953.
Dr. Niklas Aders Dr. Jan-Hendrik Lamm Katharina Wels Sophie Bernhardt Beate Neumann Dr. Hans-Georg Stammler Prof. Dr. Norbert W. Mitzel 《欧洲无机化学杂志》2023,26(17):e202300061
Herein we report the syntheses of highly rigid silicon- and tin-containing cyclic and bicyclic compounds with unsaturated organic backbones. The syntheses proceed via di-lithiated diethynylbenzene derivatives. The protocols for the known precursor compounds were significantly improved in a two-step one-pot reaction with yields up to 45 % by alternating addition of the lithiation reagent and starting material. A total of ten compounds were synthesized and the molecular structure in the solid state was elucidated for six novel compounds. Host-guest-experiments with selected molecules were conducted to investigate on the potential of the complexation of small anions. All compounds were characterized by multinuclear NMR spectroscopy and elemental analyses or mass spectrometry and in most parts by SC-XRD analyses. 相似文献
954.
Danyon M. Fischbach Katharina A. Krstic Prof. Dr. Lawrence R. Sita 《Angewandte Chemie (International ed. in English)》2023,62(31):e202304725
The (stereoselective) living coordinative copolymerization of 1-alkenes with 4-aryl-1,6-heptadienes, in both the absence and presence of multiple equivalents of a reversible chain transfer agent, is established as a highly versatile strategy for production of multivariate hyperdimensional functionalized semi-crystalline or amorphous polyolefins that optionally possess either mono- or difunctionalized (telechelic) end-groups in combination with a programmable level of incorporation of orthogonal functional groups within the main-chain. The non-conjugated diene comonomers are readily obtained from a diverse range of aryl carboxaldehyde precursors through a one-step bis-allylation process. These results serve to provide a new platform for exploring the science and technology of a vast new landscape of functionalized classes of polyolefins that are now accessible in practical and scalable quantities. 相似文献
955.
Dr. Tugce Nur Eren Dr. Florian Feist Dr. Katharina Ehrmann Prof. Dr. Christopher Barner-Kowollik 《Angewandte Chemie (International ed. in English)》2023,62(36):e202307535
Independently addressing photoreactive sites within one molecule with two colours of light is a formidable challenge. Here, we combine two sequence independent λ-orthogonal chromophores in one heterotelechelic dilinker molecule, to exploit their disparate reactivity utilizing the same reaction partner, a maleimide-containing polymer. We demonstrate that polymer network formation only proceeds if two colours of light are employed. Upon single colour irradiation, linker-decorated post-functionalized polymers are generated at either wavelength and in either sequence. Network formation, however, is only achieved by sequential or simultaneous two colour irradiation. The herein introduced photoreactive system demonstrates the power of wavelength orthogonal chemistry in macromolecular synthesis. 相似文献
956.
957.
Rong Li Julian Heuer Thomas Kuckhoff Katharina Landfester Calum T. J. Ferguson 《Angewandte Chemie (International ed. in English)》2023,62(17):e202217652
Pseudo-homogeneous polymeric photocatalysts are an emerging class of highly efficient and tunable photocatalytic materials, where the photocatalytic centers are easily accessible. The creation of highly efficient photocatalytic materials that can be rapidly separated and recovered is one of the critical challenges in photocatalytic chemistry. Here, we describe pH-responsive photocatalytic nanoparticles that are active and well-dispersed under acidic conditions but aggregate instantly upon elevation of pH, enabling easy recovery. These responsive photocatalytic polymers can be used in various photocatalytic transformations, including CrVI reduction and photoredox alkylation of indole derivative. Notably, the cationic nature of the photocatalyst accelerates reaction rate of an anionic substrate compared to uncharged species. These photocatalytic particles could be readily recycled allowing multiple successive photocatalytic reactions with no clear loss in activity. 相似文献
958.
Lukas Scheibelberger Toda Stankovic Kaja Liepert Andreas Kienzle Eva-Maria Patronas Dr. Theresa Balber Prof. Dr. Markus Mitterhauser Prof. Dr. Arvand Haschemi Dr. Katharina Pallitsch 《European journal of organic chemistry》2023,26(31):e202300339
Fluorinated carbohydrates are valuable tools for enzymological studies due to their increased metabolic stability compared to their non-fluorinated analogues. Replacing different hydroxyl groups within the same monosaccharide by fluorine allows to influence a wide range of sugar–receptor interactions and enzymatic transformations. In the past, this principle was frequently used to study the metabolism of highly abundant carbohydrates, while the metabolic fate of rare sugars is still poorly studied. Rare sugars, however, are key intermediates of many metabolic routes, such as the pentose phosphate pathway (PPP). Here we present the design and purely chemical synthesis of a set of three deoxyfluorinated analogues of the rare sugars d -xylulose and d -ribulose: 1-deoxy-1-fluoro-d -ribulose ( 1DFRu ), 3-deoxy-3-fluoro-d -ribulose ( 3DFRu ) and 3-deoxy-3-fluoro-d -xylulose ( 3DFXu ). Together with a designed set of potential late-stage radio-fluorination precursors, they have the potential to become useful tools for studies on the complex equilibria of the non-oxidative PPP. 相似文献
959.