scholarly journals Redox-responsive phosphonite gold complexes in hydroamination catalysis

2019 ◽  
Vol 55 (37) ◽  
pp. 5323-5326 ◽  
Author(s):  
Eva Deck ◽  
Hanna E. Wagner ◽  
Jan Paradies ◽  
Frank Breher
Keyword(s):  
Gold Complexes ◽  
Redox Active ◽  
Redox Responsive ◽  
Very High

Very high activities were observed in the redox-induced hydroamination of alkynes by employing a redox-active gold(i) complex featuring an electron-deficient, terphenyl-substituted phosphonite-based ligand.

scholarly journals Drawing on biology to inspire molecular design: a redox-responsive MRI probe based on Gd(iii)-nicotinamide

2018 ◽  
Vol 54 (92) ◽  
pp. 12986-12989 ◽  
Author(s):  
Michael Harris ◽  
Jacek L. Kolanowski ◽  
Edward S. O’Neill ◽  
Céline Henoumont ◽  
Sophie Laurent ◽  
...  
Keyword(s):  
Molecular Design ◽  
Biologically Inspired ◽  
Redox Active ◽  
Reversible Redox ◽  
Redox Responsive ◽  
Redox Switch

A novel, reversible redox-active MRI probe, GdNR1, has been developed based on the biologically-inspired nicotinimidium redox switch.

Buildup of Redox-Responsive Hybrid from Polyoxometalate and Redox-Active Conducting Oligomer: Its Self-Assemblies with Controllable Morphologies

2017 ◽  
Vol 23 (59) ◽  
pp. 14860-14865 ◽  
Author(s):  
Shan She ◽  
Zehuan Huang ◽  
Panchao Yin ◽  
Aruuhan Bayaguud ◽  
Hongli Jia ◽  
...  
Keyword(s):  
Redox Active ◽  
Redox Responsive

Redox-responsive host–guest system using redox-active pillar[5]arene containing one benzoquinone unit

2016 ◽  
Vol 52 (38) ◽  
pp. 6479-6481 ◽  
Author(s):  
Tomoki Ogoshi ◽  
Tomohiro Akutsu ◽  
Yasuo Shimada ◽  
Tada-aki Yamagishi
Keyword(s):  
Redox Active ◽  
Redox Responsive ◽  
Guest System

Pillar[5]arene with one benzoquinone formed weak complex with a guest, while pillar[5]arene containing one hydroquinone strongly captured the guest.

Types of Polysiloxanes

2015 ◽  
Author(s):  
James E. Mark ◽  
Dale W. Schaefer ◽  
Gui Lin
Keyword(s):  
Thin Film Transistors ◽  
Repeat Unit ◽  
Side Chain ◽  
Side Chains ◽  
Cyclic Siloxane ◽  
Scientific Interest ◽  
Vinyl Polymers ◽  
Redox Active ◽  
Methylene Groups ◽  
Very High

The polysiloxane of greatest commercial importance and scientific interest is poly(dimethylsiloxane) (PDMS), [Si(CH3)2 –O –]x, a member of the symmetrical dialkyl polysiloxanes, with repeat unit [SiR2 –O –]x. This polymer is discussed extensively in the following chapters, particularly in chapter 5. Other members of this series are poly(diethylsiloxane) [Si(C2H5) –O–]x, and poly(di-n-propylsiloxane) [SiC3H7)2–O–]x. An example of an aryl member of the symmetrically substituted series is poly(diphenylsiloxane), with repeat unit [Si(C6H5)2–O–]x. This polymer is unusual because of its very high melting point and the mesophase it exhibits. The closely related polymer, poly(phenyl/tolylsiloxane), has also been prepared and studied. The unsymmetrically substituted polysiloxanes have the repeat unit [SiRR’O–]x, and are exemplified by poly(methylphenylsiloxane) [Si(CH3) (C6H5) –O–]xand poly(methylhydrosiloxane) [Si(CH3)(H) –O–]x. In some cases, one of the side chains has been unusually long, for example C6H13, C16H33, and C18H37, including a branched side chain—CH(CH3– (CH2)m–CH3. Another example has methoxy-substituted aromatic fragments as one of the two side chains in the repeat unit. Such chains have stereochemical variability in analogy with the vinyl polymers such as polypropylene [CH(CH3) –CH2–]xand vinylidene polymers such as poly(methyl methacrylate) [C(CH3)(C = OOCH3) –CH2–]xOne can also introduce optically active groups as side chains, the simplest example being the secondary butyl group—CH(CH3)(C2H5). Another example involves redox-active dendritic wedges containing ferrocenyl and carbonylchromium moieties. Other substituents have included phenylethenyl groups, cyclic siloxane groups, and Cr-bound carbazole chromophores. In a reversal of roles, some polymers were prepared to have PDMS side chains on a poly(phenylacetylene) main chain. Siloxane-terminated solubilizing side chains are used to improve the properties of thin-film transistors. Silalkylene polymers have methylene groups replacing the oxygen atoms in the backbone. Poly(dimethylsilmethylene) is an example, [Si(CH3)2–CH2]x. A variation on this theme is to include aryl groups, for example, in poly(dimethyldiphenylsilylenemethylene) [Si(CH3)2CH2Si(C6H5)2]x. Other aryl substituents, specifically tolyl groups, have also been included as side chains. It is also possible to insert a silphenylene group [Si(CH3)2–C6H4–] into the backbone of the polysiloxane repeat unit to give [Si(CH3)2–C6H4– Si(CH3)2O–], in which the phenylene can be para or ortho or meta. A specific example is poly(tetramethyl-p-silphenylene-siloxane).

scholarly journals Nanocavity crossbar arrays for parallel electrochemical sensing on a chip

2014 ◽  
Vol 5 ◽  
pp. 1137-1143 ◽  
Author(s):  
Enno Kätelhön ◽  
Dirk Mayer ◽  
Marko Banzet ◽  
Andreas Offenhäusser ◽  
Bernhard Wolfrum
Keyword(s):  
High Spatial Resolution ◽  
Redox Cycling ◽  
Electrochemical Sensing ◽  
Wafer Surface ◽  
Novel Device ◽  
Redox Active ◽  
Parallel Data ◽  
Acquisition Mode ◽  
Parallel Band ◽  
Very High

We introduce a novel device for the mapping of redox-active compounds at high spatial resolution based on a crossbar electrode architecture. The sensor array is formed by two sets of 16 parallel band electrodes that are arranged perpendicular to each other on the wafer surface. At each intersection, the crossing bars are separated by a ca. 65 nm high nanocavity, which is stabilized by the surrounding passivation layer. During operation, perpendicular bar electrodes are biased to potentials above and below the redox potential of species under investigation, thus, enabling repeated subsequent reactions at the two electrodes. By this means, a redox cycling current is formed across the gap that can be measured externally. As the nanocavity devices feature a very high current amplification in redox cycling mode, individual sensing spots can be addressed in parallel, enabling high-throughput electrochemical imaging. This paper introduces the design of the device, discusses the fabrication process and demonstrates its capabilities in sequential and parallel data acquisition mode by using a hexacyanoferrate probe.

Structure of TSA2 reveals novel features of the active-site loop of peroxiredoxins

2016 ◽  
Vol 72 (1) ◽  
pp. 158-167 ◽  
Author(s):  
Maja Holch Nielsen ◽  
Rune Thomas Kidmose ◽  
Lasse Bohl Jenner
Keyword(s):  
Active Site ◽  
Important Determinant ◽  
High Sequence Identity ◽  
Sequence Identity ◽  
C Terminus ◽  
Redox Active ◽  
The Family ◽  
Local Unfolding ◽  
Very High ◽  
Reduced State

Saccharomyces cerevisiaeTSA2 belongs to the family of typical 2-Cys peroxiredoxins, a ubiquitously expressed family of redox-active enzymes that utilize a conserved peroxidatic cysteine to reduce peroxides. Typical 2-Cys peroxiredoxins have been shown to be involved in protection against oxidative stress and in hydrogen peroxide signalling. Furthermore, several 2-Cys peroxiredoxins, includingS. cerevisiaeTSA1 and TSA2, are able to switch to chaperone activity upon hyperoxidation of their peroxidatic cysteine. This makes the sensitivity to hyperoxidation of the peroxidatic cysteine a very important determinant for the cellular function of a peroxiredoxin under different cellular conditions. Typical 2-Cys peroxiredoxins exist as dimers, and in the course of the reaction the peroxidatic cysteine forms a disulfide with a resolving cysteine located in the C-terminus of its dimeric partner. This requires a local unfolding of the active site and the C-terminus. The balance between the fully folded and locally unfolded conformations is of key importance for the reactivity and sensitivity to hyperoxidation of the different peroxiredoxins. Here, the structure of a C48S mutant of TSA2 fromS. cerevisiaethat mimics the reduced state of the peroxidatic cysteine has been determined. The structure reveals a novel conformation for the strictly conserved Pro41, which is likely to affect the delicate balance between the fully folded and locally unfolded conformations of the active site, and therefore the reactivity and the sensitivity to hyperoxidation. Furthermore, the structure also explains the observed difference in the pKavalues of the peroxidatic cysteines ofS. cerevisiaeTSA1 and TSA2 despite their very high sequence identity.

scholarly journals Characterization of Redox-Responsive LXR-Activating Nanoparticle Formulations in Primary Mouse Macrophages

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3751 ◽  
Author(s):  
Tyler K. T. Smith ◽  
Zaina Kahiel ◽  
Nicholas D. LeBlond ◽  
Peyman Ghorbani ◽  
Eliya Farah ◽  
...  
Keyword(s):  
Potential Candidate ◽  
Beneficial Effects ◽  
Redox Active ◽  
Primary Mouse ◽  
Mouse Macrophages ◽  
Redox Responsive ◽  
Exposure In Vivo ◽  
Abca1 Protein

Activation of the transcription factor liver X receptor (LXR) has beneficial effects on macrophage lipid metabolism and inflammation, making it a potential candidate for therapeutic targeting in cardiometabolic disease. While small molecule delivery via nanomedicine has promising applications for a number of chronic diseases, questions remain as to how nanoparticle formulation might be tailored to suit different tissue microenvironments and aid in drug delivery. In the current study, we aimed to compare the in vitro drug delivering capability of three nanoparticle (NP) formulations encapsulating the LXR activator, GW-3965. We observed little difference in the base characteristics of standard PLGA-PEG NP when compared to two redox-active polymeric NP formulations, which we called redox-responsive (RR)1 and RR2. Moreover, we also observed similar uptake of these NP into primary mouse macrophages. We used the transcript and protein expression of the cholesterol efflux protein and LXR target ATP-binding cassette A1 (ABCA1) as a readout of GW-3956-induced LXR activation. Following an initial acute uptake period that was meant to mimic circulating exposure in vivo, we determined that although the induction of transcript expression was similar between NPs, treatment with the redox-sensitive RR1 NPs resulted in a higher level of ABCA1 protein. Our results suggest that NP formulations responsive to cellular cues may be an effective tool for targeted and disease-specific drug release.

Sub-nanometer expansions of redox responsive polymer films monitored by imaging ellipsometry

Nanoscale ◽  
2014 ◽  
Vol 6 (20) ◽  
pp. 12089-12095 ◽  
Author(s):  
Aysegul Cumurcu ◽  
Xueling Feng ◽  
Lionel Dos Ramos ◽  
Mark A. Hempenius ◽  
Peter Schön ◽  
...  
Keyword(s):  
Thin Films ◽  
Real Time ◽  
Electrochemical Oxidation ◽  
Imaging Ellipsometry ◽  
Oxidation Reduction ◽  
Novel Approach ◽  
Redox Active ◽  
Redox Responsive ◽  
Responsive Polymer

We describe a novel approach to quantitatively visualize sub nm height changes occurring in thin films of redox active polymers upon reversible electrochemical oxidation/reduction in situ and in real-time with electrochemical imaging ellipsometry (EC-IE).

Sign in / Sign up

Export Citation Format

Share Document