Cu-Catalyzed Couplings of Aryl Iodonium Salts with Sodium Trifluoromethanesulfinate

A convenient method for the preparation of aryl trifluoromethylsulfones from the reactions of diaryliodonium salts with sodium trifluoromethanesulfinate in the presence of copper catalysts is described. Cuprous oxide in DMF was found to be the optimal catalyst for the reaction. The reaction conditions are tolerant of various functional groups as well as of various counteranions of the iodonium salt. The synthetic utility of the process is demonstrated by performing the reaction on a preparative scale (88 g)

Nanoscale Mapping of Molecular Vibrational Modes via Vibrational Noise Spectroscopy

We have developed a “vibrational noise spectroscopy (VNS)” method to identify and map vibrational modes of molecular wires on a solid substrate. In the method, electrical-noises generated in molecules on a conducting substrate were measured using a conducting atomic force microscopy (AFM) with a nanoresolution. We found that the bias voltage applied to the conducting AFM probe can stimulate specific vibrational modes of measured molecules, resulting in enhanced electrical noises. Thus, by analyzing noise-voltage spectra, we could identify various vibrational modes of the molecular wires on the substrates. Further, we could image the distribution of vibrational modes on molecule patterns on the substrates. In addition, we found that VNS imaging data could be further analyzed to quantitatively estimate the density of a specific vibrational mode in the layers of different molecular species. The VNS method allows one to measure molecular vibrational modes under ambient conditions with a nanoresolution, and thus it can be a powerful tool for nanoscale electronics and materials researches in general

Ultrahigh Performance Supercapacitor from Lacey Reduced Graphene Oxide Nanoribbons

High performance lacey reduced graphene oxide nanoribbons (LRGONR) were chemically synthesized. Holes created during the LRGONR synthesis not only enhanced the electrolytic accessibility but destacked all the graphene layers through protrusion at edge planes and corrugation in individual graphene. LRGONR in a supercapacitor cell showed ultrahigh performance in terms of specific capacitance and capacity retention. Consistently in aqueous, nonaqueous, and ionic electrolytes, LRGONR symmetric supercapacitor exhibited exceptionally high energy/power density, typically 15.06 W h kg^–1/807 W kg^–1 in aqueous at 1.7 A g^–1, 90 W h kg^–1/2046.8 W kg^–1 in nonaqueous at 1.8 A g^–1, and 181.5 W h kg^–1/2316.8 W kg^–1 in ionic electrolyte at ∼1.6 A g^–1

Nanoscale Direct Mapping of Noise Source Activities on Graphene Domains

An electrical noise is one of the key parameters determining the performance of modern electronic devices. However, it has been extremely difficult, if not impossible, to image localized noise sources or their activities in such devices. We report a “noise spectral imaging” strategy to map the activities of localized noise sources in graphene domains. Using this method, we could quantitatively estimate sheet resistances and noise source densities inside graphene domains, on domain boundaries and on the edge of graphene. The results show high activities of noise sources and large sheet resistance values at the domain boundary and edge of graphene. Additionally, we showed that the top layer in double-layer graphene had lower noises than single-layer graphene. This work provides valuable insights about the electrical noises of graphene. Furthermore, the capability to directly map noise sources in electronic channels can be a major breakthrough in electrical noise research in general

Ligand-Controlled Synthesis of Azoles via Ir-Catalyzed Reactions of Sulfoxonium Ylides with 2‑Amino Heterocycles

An iridium-catalyzed method was developed for the synthesis of imidazo-fused pyrrolopyrazines. The presence or absence of a nitrogenated ligand controlled the outcome of the reaction, leading to simple β-keto amine products in the absence of added ligand and the cyclized 7- and 8-substituted-imidazo­[1,2<i>-a</i>]­pyrrolo­[2,3<i>-e</i>]­pyrazine products in the presence of ligand. This catalyst control was conserved across a variety of ylide and amine coupling partners. The substrate was shown to act as a ligand for the iridium catalyst in the absence of other ligands via NMR spectroscopy. Kinetic studies indicated that formation of the Ir-carbene was reversible and the slow step of the reaction. These mechanistic investigations suggest that the β-keto amine products form via an intramolecular carbene N–H insertion, and the imidazopyrrolopyrazines form via an intermolecular carbene N–H insertion

<i>puc</i> gain of function does not affect the MAPK network topology but influences intrinsic network interactions.

<p>We calculated activation ratios to best fit the FRET measurements upon Puc overexpression at rest (<b>A</b>) or upon stretch (<b>B</b>). The extrinsic inputs into the network (Bsk, Rl; ΣKin; Puc loop) (<b>C</b>) and the intrinsic positive and negative interactions (activity levels) between the network's different nodes (Bsk, Rl; ΣKin; Puc; Puc loop) (<b>D</b>) were determined by fitting. Components concentrations and levels of activation or repression are displayed as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101963#pone-0101963-g004" target="_blank">Figure 4</a>.</p

MAPKs Network Dynamic Model.

<p>To build the network, we took into account three elements, Puc, Bsk, and Rl plus an additional component (ΣKin) integrating all other potentially involved kinases (such as P38s). We considered that the dJun-FRET biosensor could be activated at different levels by Bsk, Rl and ΣKin, that the expression of Puc in response to dJun phosphorylation was only triggered by Bsk, and that Puc inhibit all kinases Bsk, Rl and ΣKin with different affinities. We further established two other biochemical links: a negative input from Rl onto Bsk function (activation of Puc expression) and a positive feedback loop from Puc upstream of Rl. We then determined a set of parameters allowing calculated activation ratios to best fit the FRET measurements of single, and double knockdowns and the control condition at rest (<b>A</b>) or upon stretch (<b>B</b>). We further evaluated the model taking into consideration the epistatic analysis performed on <i>rac1</i> at rest (<b>C</b>) and upon stretch (<b>D</b>). Components concentrations (font size) and levels of activation or repression (rainbow look up table) are displayed according to logarithmic scales following the values defined in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101963#pone.0101963.s004" target="_blank">Table S4</a>.</p

Distinct roles for kinases and phosphatases during mechanical stretch activation.

<p><i>Drosophila</i> S2R+ cells were co-transfected with the pAct-dJun-FRET and different dsRNAs. <b>A</b>) <i>bsk⁻</i>. <b>B</b>) <i>hep⁻</i>. <b>C</b>) <i>slpr⁻</i>. <b>D</b>) <i>msn⁻</i>. <b>E</b>) <i>p38α⁻</i>. <b>F</b>) <i>p38β⁻</i>. <b>G</b>) <i>rl⁻</i>. <b>H</b>) <i>puc⁻</i>. Fluorescence lifetimes (FL) for the donor mCFP were collected and curves representing data recorded from ∼75 cells for cells at rest. Blue data points denote the measurements obtained at rest while red data points show the measurements obtained after 3 hours of continuous static stretch. In each panel, the purple bar represents the average FL determined for control wild type cells at rest, while the cyan bar represents the average FL of control wild type cells stretched for 3 hours.</p

Epistatic interactions between <i>bsk, rl</i> and <i>puc</i> at rest and upon mechanical stretch.

<p>Graphical representation of the averaged FL values of cells co-transfected with the pAct-dJun-FRET biosensor and single or double combinations of dsRNAs. <b>A</b>) at rest. <b>B</b>) upon stretch. Black - <i>bsk⁻</i>; Red - <i>rl⁻</i>; Blue - <i>puc⁻</i>; pale Green - double treatment for each paired combination. Purple and Cyan bars represents the average FL for wild type cells at rest and upon stretch as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0101963#pone-0101963-g001" target="_blank">Figure 1</a>.</p

Copper-Catalyzed Aerobic Oxidative Amidation of Benzyl Alcohols

A Cu-catalyzed synthesis of amides from alcohols and secondary amines using the oxygen in air as the terminal oxidant has been developed. The methodology is operationally simple requiring no high pressure equipment or handling of pure oxygen. The commercially available, nonprecious metal catalyst, Cu­(phen)­Cl₂, in conjunction with di-<i>tert</i>-butyl hydrazine dicarboxylate and an inorganic base provides a variety of benzamides in moderate to excellent yields. The p<i>K</i>_a of amine conjugate acid and electronics of alcohol were shown to impact the selection of base for optimal reactivity. A mechanism consistent with the observed reactivity trends, KIE, and Hammett study is proposed