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91.
José Luis Fonseca María José Sosa Gabriela Petroselli Rosa Erra-Balsells Matías I. Quindt Sergio M. Bonesi Alexander Greer Edyta M. Greer Andrés H. Thomas Mariana Vignoni 《Photochemistry and photobiology》2023,99(2):593-604
Here, we provide mechanistic insight to the photocleavage of a compound in the folate family, namely pteroic acid. A bis-decyl chain derivative of pteroic acid was synthesized, structurally characterized and photochemically investigated. We showed that, like folic acid, pteroic acid and the decylated derivative undergo a photocleavage reaction in the presence of H2O, while no reaction was observed in methanol solution. Furthermore, density functional theory calculations were carried out to predict relative stabilities of hypothetical mono-, bis- and tris-decylated pteroic acid derivatives to help rationalize the regioselectivity of the bis-decyl pteroic acid product. Additionally, the lipophilicity of the bis-decyl pteroic acid appears to confer a hydrophobic property enabling an interaction with biomembranes. 相似文献
92.
Maxim N. Moskovsky Yuri H. Shogenov Alexander V. Lavrov Anatoly A. Gulyaev Igor Yu. Efremenkov Denis S. Pyatchenkov Mikhail V. Belyakov 《Photochemistry and photobiology》2023,99(1):29-34
We needed effective and sustainable technologies for better microbiological control of crops, including Fusarium. However, photoluminescent UV–Vis methods are potential for diagnosing plant diseases with Fusarium. It has not been sufficiently studied despite the application of these methods for other biological researches. The excitation spectrum of the seeds during infection shifts to the shorter wavelength and a new maximum appears in the region λ ≈ 232 nm. The photoluminescence of infected seeds increases with excitation by radiation of wavelengths λe,1 = 232 nm, λe,2 = 362 nm and λe,3 = 424 nm by 1.33–3.14 times, and λe,3 = 424 nm—decreases by 1.1 times. Statistical moments μ3 and μ4, asymmetry and kurtosis change only with short-wave excitation. When analyzing the decomposition of the frequency spectrum into Gaussian curves, the most informative ratio is the ratio of right-handed and left-handed Gaussians under excitation λe,2 = 362 nm and λe,3 = 424 nm. The ratios of their maxima change during infection by 1.36–3.2 times, and for excitation by radiation λe,2, the frequency boundaries of Gaussians change. The results of measurements and calculations provide a basis for the development of a method and device for photoluminescence diagnostics of fusarium seeds in UV–Vis ranges. 相似文献
93.
Rebecca Wiesner Holger Zagst Wenkui Lan Stewart Bigelow Peter Holper Göran Hübner Leila Josefsson Claire Lancaster Lili Lo Christopher Lößner Huixin Lu Christian Neusüß Carolin Rüttiger Johannes Schlecht Philipp Schürrle Alexander Selsam Debbie van der Burg Shao-Chun Wang Yunxiao Zhu Hermann Wätzig Cari Sänger-van de Griend 《Electrophoresis》2023,44(15-16):1247-1257
Capillary zone electrophoresis ultraviolet (CZE-UV) has become increasingly popular for the charge heterogeneity determination of mAbs and vaccines. The ε-aminocaproic acid (eACA) CZE-UV method has been used as a rapid platform method. However, in the last years, several issues have been observed, for example, loss in electrophoretic resolution or baseline drifts. Evaluating the role of eACA on the reported issues, various laboratories were requested to provide their routinely used eACA CZE-UV methods, and background electrolyte compositions. Although every laboratory claimed to use the He et al. eACA CZE-UV method, most methods actually deviate from He's. Subsequently, a detailed interlaboratory study was designed wherein two commercially available mAbs (Waters’ Mass Check Standard mAb [pI 7] and NISTmAb [pI 9]) were provided to each laboratory, along with two detailed eACA CZE-UV protocols for a short-end, high-speed, and a long-end, high-resolution method. Ten laboratories participated each using their own instruments, and commodities, showing excellence method performance (relative standard deviations [RSDs] of percent time-corrected main peak areas from 0.2% to 1.9%, and RSDs of migration times from 0.7% to 1.8% [n = 50 per laboratory], analysis times in some cases as short as 2.5 min). This study clarified that eACA is not the main reason for the abovementioned variations. 相似文献
94.
Christoph Riesinger Prof. Dr. Fabian Dielmann Robert Szlosek Dr. Alexander V. Virovets Prof. Dr. Manfred Scheer 《Angewandte Chemie (International ed. in English)》2023,62(16):e202218828
The thermolysis of Cp′′′Ta(CO)4 with white phosphorus (P4) gives access to [{Cp′′′Ta}2(μ,η2 : 2 : 2 : 2 : 1 : 1-P8)] ( A ), representing the first complex containing a cyclooctatetraene-like (COT) cyclo-P8 ligand. While ring sizes of n >6 have remained elusive for cyclo-Pn structural motifs, the choice of the transition metal, co-ligand and reaction conditions allowed the isolation of A . Reactivity investigations reveal its versatile coordination behaviour as well as its redox properties. Oxidation leads to dimerization to afford [{Cp′′′Ta}4(μ4,η2 : 2 : 2 : 2 : 2 : 2 : 2 : 2 : 1 : 1 : 1 : 1-P16)][TEF]2 ( 4 , TEF=[Al(OC{CF3}3)4]−). Reduction, however, leads to the fission of one P−P bond in A followed by rapid dimerization to form [K@[2.2.2]cryptand]2[{Cp′′′Ta}4(μ4,η2 : 2 : 2 : 2 : 2 : 2 : 2 : 2 : 1 : 1 : 1 : 1-P16)] ( 5 ), which features an unprecedented chain-type P16 ligand. Lastly, A serves as a P2 synthon, via ring contraction to the triple-decker complex [{Cp′′′Ta}2(μ,η6 : 6-P6)] ( B ). 相似文献
95.
Mercie N. Hodges Matthew J. Elardo Jinyoung Seo Alexander F. Dohoda Prof. Dr. Forrest E. Michael Prof. Dr. Matthew R. Golder 《Angewandte Chemie (International ed. in English)》2023,62(20):e202303115
Accumulation of end-of-life plastics presents ongoing environmental concerns. One strategy to solve this grand challenge is to invent new techniques that modify post-consumer waste and impart new functionality. While promising approaches for the chemical upcycling of commodity polyolefins and polyaromatics exist, analogous approaches to repurpose unsaturated polymers (e.g., polybutadiene) are scarce. In this work, we propose a method to upcycle polybutadiene, one of the most widely used commercial rubbers, via a mild, metal-free allylic amination reaction. The resulting materials have tunable thermal and surface wetting properties as a function of both sulfonamide identity and grafting density. Importantly, this approach maintains the parent alkene microstructure without evidence of olefin reduction, olefin transposition, and/or chain scission. Based on these findings, we anticipate future applications in the remediation of complex elastomers and vulcanized rubbers. 相似文献
96.
Matthias Uhl Tanja Geng Philipp A. Schuster Benjamin W. Schick Matthias Kruck Alexander Fuoss Prof. Dr. Alexander J. C. Kuehne Prof. Dr. Timo Jacob 《Angewandte Chemie (International ed. in English)》2023,62(2):e202214927
For sustainable energy storage, all-organic batteries based on redox-active polymers promise to become an alternative to lithium ion batteries. Yet, polymers contribute to the goal of an all-organic cell as electrodes or as solid electrolytes. Here, we replace the electrolyte with a deep eutectic solvent (DES) composed of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and N-methylacetamide (NMA), while using poly(2,2,6,6-tetramethylpiperidin-1-yl-oxyl methacrylate) (PTMA) as cathode. The successful combination of a DES with a polymer electrode is reported here for the first time. The electrochemical stability of PTMA electrodes in the DES at the eutectic molar ratio of 1 : 6 is comparable to conventional battery electrolytes. More viscous electrolytes with higher salt concentration can hinder cycling at high rates. Lower salt concentration leads to decreasing capacities and faster decomposition. The eutectic mixture of 1 : 6 is best suited uniting high stability and moderate viscosity. 相似文献
97.
Dr. Nahyun Kwon Gabriel O. Jasinevicius Dr. Giulia Kassab Lili Ding Jiachuan Bu Letícia P. Martinelli Dr. Vinicius G. Ferreira Alexander Dhaliwal Dr. Harley H. L. Chan Yulin Mo Dr. Vanderlei S. Bagnato Prof. Dr. Cristina Kurachi Dr. Juan Chen Prof. Dr. Gang Zheng Prof. Dr. Hilde H. Buzzá 《Angewandte Chemie (International ed. in English)》2023,62(28):e202305564
Indocyanine green (ICG) is the only near-infrared (NIR) dye approved for clinical use. Despite its versatility in photonic applications and potential for photothermal therapy, its photobleaching hinders its application. Here we discovered a nanostructure of dimeric ICG (Nano-dICG) generated by using ICG to stabilize nanoemulsions, after which ICG enabled complete dimerization on the nanoemulsion shell, followed by J-aggregation of ICG-dimer, resulting in a narrow, red-shifted (780 nm→894 nm) and intense (≈2-fold) absorbance. Compared to ICG, Nano-dICG demonstrated superior photothermal conversion (2-fold higher), significantly reduced photodegradation (−9.6 % vs. −46.3 %), and undiminished photothermal effect (7 vs. 2 cycles) under repeated irradiations, in addition to excellent colloidal and structural stabilities. Following intravenous injection, Nano-dICG enabled real-time tracking of its delivery to mouse tumors within 24 h by photoacoustic imaging at NIR wavelength (890 nm) distinct from the endogenous signal to guide effective photothermal therapy. The unprecedented finding of nanostructure-driven ICG dimerization leads to an ultra-stable phototheranostic platform. 相似文献
98.
Alexander Goller Dr. Johannes Obenauf Dr. Winfried P. Kretschmer Prof. Dr. Rhett Kempe 《Angewandte Chemie (International ed. in English)》2023,62(8):e202216464
The highly controlled and efficient polymerization of ethylene is a very attractive but challenging target. Herein we report on a Coordinative Chain Transfer Polymerization catalyst, which combines a high degree of control and very high activity in ethylene oligo- or polymerization with extremely high chain transfer agent (triethylaluminum) to catalyst ratios (catalyst economy). Our Zr catalyst is long living and temperature stable. The chain length of the polyethylene products increases over time under constant ethylene feed or until a certain volume of ethylene is completely consumed to reach the expected molecular weight. Very high activities are observed if the catalyst elongates 60 000 or more alkyl chains and the polydispersity of the strictly linear polyethylene materials obtained are very low. The key for the combination of high control and efficiency seems to be a catalyst stabilized by only one strongly bound monoanionic N-ligand. 相似文献
99.
Kinran Lau Felix Niemann Dr. Kaltum Abdiaziz Dr. Markus Heidelmann Yuke Yang Dr. Yujin Tong Dr. Michael Fechtelkord Prof. Torsten C. Schmidt Dr. Alexander Schnegg Prof. R. Kramer Campen Dr. Baoxiang Peng Prof. Martin Muhler Dr. Sven Reichenberger Prof. Stephan Barcikowski 《Angewandte Chemie (International ed. in English)》2023,62(12):e202213968
Both oxygen vacancies and surface hydroxyls play a crucial role in catalysis. Yet, their relationship is not often explored. Herein, we prepare two series of TiO2 (rutile and P25) with increasing oxygen deficiency and Ti3+ concentration by pulsed laser defect engineering in liquid (PUDEL), and selectively quantify the acidic and basic surface OH by fluoride substitution. As indicated by EPR spectroscopy, the laser-generated Ti3+ exist near the surface of rutile, but appear to be deeper in the bulk for P25. Fluoride substitution shows that extra acidic bridging OH are selectively created on rutile, while the surface OH density remains constant for P25. These observations suggest near-surface Ti3+ are highly related to surface bridging OH, presumably the former increasing the electron density of the bridging oxygen to form more of the latter. We anticipate that fluoride substitution will enable better characterization of surface OH and its correlation with defects in metal oxides. 相似文献
100.
Alexander D. Fusi Yudong Li Dr. A. Llopis-Lorente Dr. Tania Patiño Prof. Dr. Jan C. M. van Hest Dr. Loai K. E. A. Abdelmohsen 《Angewandte Chemie (International ed. in English)》2023,62(5):e202214754
Unprecedented opportunities exist for the generation of advanced nanotechnologies based on synthetic micro/nanomotors (MNMs), such as active transport of medical agents or the removal of pollutants. In this regard, great efforts have been dedicated toward controlling MNM motion (e.g., speed, directionality). This was generally performed by precise engineering and optimizing of the motors′ chassis, engine, powering mode (i.e., chemical or physical), and mechanism of motion. Recently, new insights have emerged to control motors mobility, mainly by the inclusion of different modes that drive propulsion. With high degree of synchronization, these modes work providing the required level of control. In this Minireview, we discuss the diverse factors that impact motion; these include MNM morphology, modes of mobility, and how control over motion was achieved. Moreover, we highlight the main limitations that need to be overcome so that such motion control can be translated into real applications. 相似文献