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91.
Prof. Dr. David J. Harding Darunee Sertphon Prof. Dr. Phimphaka Harding Prof. Dr. Keith S. Murray Dr. Boujemaa Moubaraki Prof. Dr. John D. Cashion Harry Adams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):1082-1090
A new synthesis of (8‐quinolyl)‐5‐methoxysalicylaldimine (Hqsal‐5‐OMe) is reported and its crystal structure is presented. Two FeIII complexes, [Fe(qsal‐5‐OMe)2]Cl ? solvent (solvent=2 MeOH ? 0.5 H2O ( 1 ) and MeCN ? H2O ( 2 )) have been prepared and their structural, electronic and magnetic properties studied. [Fe(qsal‐5‐OMe)2] Cl ? 2 MeOH ? 0.5 H2O ( 1 ) exhibits rare crystallographically independent high‐spin and low‐spin FeIII centres at 150 K, whereas [Fe(qsal‐5‐OMe)2]Cl ? MeCN ? H2O ( 2 ) is low spin at 100 K. In both structures there are extensive π–π and C? H???π interactions. SQUID magnetometry of 2 reveals an unusual abrupt stepped‐spin crossover with T1/2=245 K and 275 K for steps 1 and 2, respectively, with a slight hysteresis of 5 K in the first step and a plateau of 15 K between the steps. In contrast, 1 is found to undergo an abrupt half‐spin crossover also with a hysteresis of 10 K. The two compounds are the first FeIII complexes of a substituted qsal ligand to exhibit abrupt spin crossover. These conclusions are supported by 57Fe Mössbauer spectroscopy. Both complexes exhibit reversible reduction to FeII at ?0.18 V and irreversible oxidation of the coordinated qsal‐5‐OMe ligand at +1.10 V. 相似文献
92.
Christopher?L.?DancyEmail author Frank?E.?Ritter Keith?A.?Berry Laura?C.?Klein 《Computational & Mathematical Organization Theory》2015,21(1):90-114
Adding a physiological representation to a cognitive architecture offers an attractive approach to modeling the effects of stress on cognition. We introduce ACT-R/Φ, an extended version of the ACT-R cognitive architecture that includes an integrative model of physiology. The extension allows the representation of how physiology and cognition interact. This substrate was used to represent potential effects of a startle response and task-based stress during a mental arithmetic (subtraction) task. We compare predictions from two models loaded into the new hybrid architecture to models previously developed within ACT-R. General behavior differed between models in that the ACT-R/Φ models had dynamic declarative memory noise over the course of the task based on varying epinephrine levels. They attempted more subtractions but were less accurate; this more closely matched human performance than the previous ACT-R models. Using ACT-R/Φ allows a more tractable integration of current physiological and cognitive perspectives on stress. ACT-R/Φ also permits further exploration of the interaction between cognition and physiology, and the emergent effects on behavior caused by the interaction among physiological subsystems. This extension is useful for anyone exploring how the human mind can occur in and be influenced by the physical universe. 相似文献
93.
‘Soft energy’ provided within a thin film microfluidic platform, namely a vortex fluidic device (VFD), is effective in accelerating and promoting Diels–Alder reactions in the absence of any catalyst. Diels–Alder cycloadducts generated from different 9-substituted anthracenes and N-maleimides are formed in high yield in an aqueous medium using the confined mode of operation of the VFD. 相似文献
94.
Meike Koenig Tadas Kasputis Daniel Schmidt Keith B. Rodenhausen Klaus-Jochen Eichhorn Angela K. Pannier Mathias Schubert Manfred Stamm Petra Uhlmann 《Analytical and bioanalytical chemistry》2014,406(28):7233-7242
A combined setup of quartz crystal microbalance and generalized ellipsometry can be used to comprehensively investigate complex functional coatings comprising stimuli-responsive polymer brushes and 3D nanostructures in a dynamic, noninvasive in situ measurement. While the quartz crystal microbalance detects the overall change in areal mass, for instance, during a swelling or adsorption process, the generalized ellipsometry data can be evaluated in terms of a layered model to distinguish between processes occurring within the intercolumnar space or on top of the anisotropic nanocolumns. Silicon films with anisotropic nanocolumnar morphology were prepared by the glancing angle deposition technique and further functionalized by grafting of poly-(acrylic acid) or poly-(N- isopropylacrylamide) chains. Investigations of the thermoresponsive swelling of the poly-(N-isopropylacrylamide) brush on the Si nanocolumns proved the successful preparation of a stimuli-responsive coating. Furthermore, the potential of these novel coatings in the field of biotechnology was explored by investigation of the adsorption of the model protein bovine serum albumin. Adsorption, retention, and desorption triggered by a change in the pH value is observed using poly-(acrylic acid) functionalized nanostructures, although generalized ellipsometry data revealed that this process occurs only on top of the nanostructures. Poly-(N-isopropylacrylamide) is found to render the nanostructures non-fouling properties. 相似文献
95.
Varamesh Amir Prathapan Ragesh Telmadarreie Ali Li Jia Gourlay Keith Minhas Gurminder Lu Qingye Bryant Steven L. Hu Jinguang 《Cellulose (London, England)》2022,29(2):985-1001
Cellulose - There has been significant interest over recent years in the production and application of sustainable and green materials. Among these, nanocellulose has incurred great interest... 相似文献
96.
Lukas Rochlitz Keith Searles Darryl F. Nater Scott R. Docherty Domenico Gioffrè Christophe Copéret 《Helvetica chimica acta》2021,104(7):e2100078
Propane dehydrogenation is an important field of research due to an increasing world-wide demand of propene while classical production routes through naphtha cracking are in decline. In that context, silica-supported Ga(III) sites, synthesized from surface organometallic chemistry principles, show high selectivity and stability in the propane dehydrogenation reaction. This performance is in significant contrast to the reported fast deactivation and lower selectivity of most Ga2O3 and CrO3 based materials. The Ga-catalyzed propane dehydrogenation reaction is proposed to proceed through the formation of Ga alkyl intermediates for which it would be desirable to have detailed structural and spectroscopic information. Here, we prepare a consistent series of Ga(III) molecular complexes with varying numbers of alkyl and siloxide ligands; they are characterized by single crystal X-Ray diffraction and X-Ray Absorption Near Edge Structure analysis, which is known to be highly sensitive to the Ga coordination environment. We report in particular the structure and the spectroscopic signatures of [Ga(iPr)(OSi(OtBu)3)2(HOSi(OtBu)3)], a molecular mimic of the key proposed reaction intermediates in the Ga-catalyzed PDH reaction. 相似文献
97.
98.
Jan?C.?Myland Keith?B.?OldhamEmail author 《Journal of Solid State Electrochemistry》2014,18(12):3259-3269
The popular inlaid disc electrode suffers from an edge effect that is usually, and sometimes unwarrantedly, ignored in analyzing transient voltammograms. This study addresses the role played by the edge in linear scan and cyclic voltammetries when the electron transfer is reversible or quasi-reversible. A simulation models the concentrations, current densities and currents in two circumstances—when the edge in important and when it is absent—simultaneously, and thereby the evolving edge current is quantified. Special attention is paid to the effect that the edge has on the heights and positions of the voltammetric peaks. It is demonstrated that disregarding the edge may lead to the bogus classification of a reversible electrode reaction as quasi-reversible. 相似文献
99.
Back Cover: Synthesis,Characterization, Self‐Assembly,Gelation, Morphology and Computational Studies of Alkynylgold(III) Complexes of 2,6‐Bis(benzimidazol‐2′‐yl)pyridine Derivatives (Chem. Eur. J. 32/2014) 下载免费PDF全文
100.
Redesigning the DNA‐Targeted Chromophore in Platinum–Acridine Anticancer Agents: A Structure–Activity Relationship Study 下载免费PDF全文
Dr. Amanda J. Pickard Dr. Fang Liu Thomas F. Bartenstein Laura G. Haines Dr. Keith E. Levine Prof. Gregory L. Kucera Prof. Ulrich Bierbach 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16174-16187
Platinum–acridine hybrid agents show low‐nanomolar potency in chemoresistant non‐small cell lung cancer (NSCLC), but high systemic toxicity in vivo. To reduce the promiscuous genotoxicity of these agents and improve their pharmacological properties, a modular build–click–screen approach was used to evaluate a small library of twenty hybrid agents containing truncated and extended chromophores of varying basicities. Selected derivatives were resynthesized and tested in five NSCLC cell lines representing large cell, squamous cell, and adenocarcinomas. 7‐Aminobenz[c]acridine was identified as a promising scaffold in a hybrid agent ( P1–B1 ) that maintained submicromolar activity in several of the DNA‐repair proficient and p53‐mutant cancer models, while showing improved tolerability in mice by 32‐fold compared to the parent platinum–acridine ( P1–A1 ). The distribution and DNA/RNA adduct levels produced by the acridine‐ and benz[c]acridine‐based analogues in NCI‐H460 cells (confocal microscopy, ICP‐MS), and their ability to bind G‐quadruplex forming DNA sequences (CD spectroscopy, HR‐ESMS) were studied. P1–B1 emerges as a less genotoxic, more tolerable, and potentially more target‐selective hybrid agent than P1–A1 . 相似文献