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1.
Transport in Porous Media - Membrane filtration of feed containing multiple species of particles is a common process in the industrial setting. In this work, we propose a model for filtration of a... 相似文献
2.
Cover Picture: Coordination Chemistry of N‐Heterocyclic Nitrenium‐Based Ligands (Chem. Eur. J. 19/2015) 下载免费PDF全文
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Cover Picture: Mild and Low‐Pressure fac‐Ir(ppy)3‐Mediated Radical Aminocarbonylation of Unactivated Alkyl Iodides through Visible‐Light Photoredox Catalysis (Chem. Eur. J. 27/2016) 下载免费PDF全文
5.
Juanita C. Limas Linda C. Corcoran Alexander N. Baker Ana E. Cartaya Dr. Zoë J. Ayres 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(9):e202102957
The onset of COVID-19, coupled with the finer lens placed on systemic racial disparities within our society, has resulted in increased discussions around mental health. Despite this, mental health struggles in research are still often viewed as individual weaknesses and not the result of a larger dysfunctional research culture. Mental health interventions in the science, technology, engineering, and mathematics (STEM) academic community often focus on what individuals can do to improve their mental health instead of focusing on improving the research environment. In this paper, we present four aspects of research that may heavily impact mental health based on our experiences as research scientists: bullying and harassment; precarity of contracts; diversity, inclusion, and accessibility; and the competitive research landscape. Based on these aspects, we propose systemic changes that institutions must adopt to ensure their research culture is supportive and allows everyone to thrive. 相似文献
6.
Saqib Kamal Arif I. Inamdar Kuan-Ru Chiou Batjargal Sainbileg Muhammad Usman Jenq-Wei Chen Tzuoo-Tsair Luo Michitoshi Hayashi Chen-Hsiung Hung Wen-Feng Liaw Kuang-Lieh Lu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(30):e202103905
The dielectric properties of coordination polymers has been a topic of recent interest, but the role of different functional groups on the dielectric properties of these polymers has not yet been fully addressed. Herein, the effects of electron-donating (R=NH2) and electron-withdrawing (R=NO2) groups on the dielectric behavior of such materials were investigated for two thermally stable and guest-free Zn-based coordination polymers, [Zn(L1)(L2)]n ( 1 ) and [Zn(L1)(L3)]n ( 2 ) [L1=2-(2-pyridyl) benzimidazole (Pbim), L2=5-aminoisophthalate (Aip), and L3=5-nitroisophthalate (Nip)]. The results of dielectric studies of 1 revealed that it possesses a high dielectric constant (κ=65.5 at 1 kHz), while compound 2 displayed an even higher dielectric constant (κ=110.3 at 1 kHz). The electron donating and withdrawing effects of the NH2 and NO2 substituents induce changes in the polarity of the polymers, which is due to the inductive effect from the aryl ring for both NO2 and NH2. Theoretical results from density functional theory (DFT) calculations, which also support the experimental findings, show that both compounds have a distinct electronic behavior with diverse wide bandgaps. The significance of the current work is to provide information about the structure-dielectric property relationships. So, this study promises to pave the way for further research on the effects of different functional groups on coordination polymers on their dielectric properties. 相似文献
7.
In developing countries, subsistence gold mining entails mixing metallic mercury with crushed sediments to extract gold. In this approach, the gold−mercury amalgam is heated to evaporate mercury and obtain gold. Thus, the highly volatile mercury can be absorbed through inhalation, resulting in adverse health effects. Urinalysis can be used to detect mercury, which is excreted in urine and feces, and correlate exposure with toxic effects. The current gold standard analytical methods are based on fluorescence or inductively coupled plasma mass spectrometry methods, but are expensive, time consuming, and are not easily accessible in countries where testing is needed. In this work, we report on a miniature electrochemical sensor that can rapidly detect mercury in urine at levels well below the US Biological Exposure Index (BEI) limit of 50 ppb (μg/L). The sensor is based on a thin-film gold electrode and anodic stripping voltammetry electroanalytical approach. The sensor successfully detected mercury at trace levels in urine, with a limit of detection of ∼15 ppb Hg in the linear range of 20–80 ppb. With the low-cost disposable sensors and portable instrumentation, it is well suited for point-of-care applications. 相似文献
8.
Llorenç Rubert Dr. Md Faizul Islam Dr. Andrew B. Greytak Rahul Prakash Mark D. Smith Dr. Rosa Maria Gomila Prof. Dr. Antonio Frontera Prof. Dr. Linda S. Shimizu Dr. Bartolome Soberats 《Angewandte Chemie (International ed. in English)》2023,62(46):e202312223
We report on a dendronized bis-urea macrocycle 1 self-assembling via a cooperative mechanism into two-dimensional (2D) nanosheets formed solely by alternated urea-urea hydrogen bonding interactions. The pure macrocycle self-assembles in bulk into one-dimensional liquid-crystalline columnar phases. In contrast, its self-assembly mode drastically changes in CHCl3 or tetrachloroethane, leading to 2D hydrogen-bonded networks. Theoretical calculations, complemented by previously reported crystalline structures, indicate that the 2D assembly is formed by a brick-like hydrogen bonding pattern between bis-urea macrocycles. This assembly is promoted by the swelling of the trisdodecyloxyphenyl groups upon solvation, which frustrates, due to steric effects, the formation of the thermodynamically more stable columnar macrocycle stacks. This work proposes a new design strategy to access 2D supramolecular polymers by means of a single non-covalent interaction motif, which is of great interest for materials development. 相似文献
9.
Dr. Linda Iffland-Mühlhaus Dr. Beatrice Battistella Dr. Daniel Siegmund Prof. Dr. Kallol Ray Prof. Dr. Ulf-Peter Apfel 《欧洲无机化学杂志》2023,26(30):e202300418
Cobalt complexes are extensively studied as bioinspired models for non-heme oxygenases as they facilitate both the stabilization and characterization of metal-oxygen intermediates. As an analog to the well-known Co(cyclam) complex Co{N4} (cyclam=1,4,8,11-tetraazacyclotetradecane), the CoII complex Co{i-N4} with the isomeric isocyclam ligand (isocyclam=1,4,7,11-tetraazacyclotetradecane) was synthesized and characterized. Despite the identical N4 donor set of both complexes, Co{i-N4} enables the 2e−/2H+ reduction of O2 with a lower overpotential (ηeff of 385 mV vs. 540 mV for Co{N4} ), albeit with a diminished turnover frequency. Characterization of the intermediates formed upon O2 activation of Co{i-N4} reveals a structurally identified stable μ-peroxo CoIII dimer as the main product. A superoxo CoIII species is also formed as a minor product, as indicated by EPR spectroscopy. In further reactivity studies, the electrophilicity of these in situ generated Co−O2 species was demonstrated by the oxidation of the O−H bond of TEMPO−H (2,2,6,6-tetramethylpiperidin-1-ol) via a H atom abstraction process. Unlike the known Co(cyclam), Co{i-N4} can be employed in oxygen atom transfer reactions oxidizing triphenylphosphine to the corresponding phosphine oxide highlighting the impact of geometrical modifications of the ligand while preserving the ring size and donor atom set on the reactivity of biomimetic oxygen activating complexes. 相似文献
10.
Design and Synthesis of High‐Affinity Dimeric Inhibitors Targeting the Interactions between Gephyrin and Inhibitory Neurotransmitter Receptors 下载免费PDF全文
Dr. Hans Michael Maric Vikram Babu Kasaragod Dr. Linda Haugaard‐Kedström Dr. Torben Johann Hausrat Prof. Dr. Matthias Kneussel Prof. Dr. Hermann Schindelin Prof. Dr. Kristian Strømgaard 《Angewandte Chemie (International ed. in English)》2015,54(2):490-494
Gephyrin is the central scaffolding protein for inhibitory neurotransmitter receptors in the brain. Here we describe the development of dimeric peptides that inhibit the interaction between gephyrin and these receptors, a process which is fundamental to numerous synaptic functions and diseases of the brain. We first identified receptor‐derived minimal gephyrin‐binding peptides that displayed exclusive binding towards native gephyrin from brain lysates. We then designed and synthesized a series of dimeric ligands, which led to a remarkable 1220‐fold enhancement of the gephyrin affinity (KD=6.8 nM ). In X‐ray crystal structures we visualized the simultaneous dimer‐to‐dimer binding in atomic detail, revealing compound‐specific binding modes. Thus, we defined the molecular basis of the affinity‐enhancing effect of multivalent gephyrin inhibitors and provide conceptually novel compounds with therapeutic potential, which will allow further elucidation of the gephyrin–receptor interplay. 相似文献