α,α'-Diamino--tetrafluoroquinodimethane: Stability of One- and Two-Electron Oxidized Species and Fixation of Molecular Oxygen.

Herein, we report the synthesis, characterization, and reactivity of α,α'-diamino--tetrafluoroquinodimethane, a -tetrafluorophenylene-bridged monosubstituted carbene-based Thiele's hydrocarbon . The compound exhibits a reversible two-step one-electron oxidation with a marginally stable radical cation state . The formation of the radical cation could be confirmed by electron paramagnetic resonance spectroscopy.

Extending the Cyclability of Alkaline Zinc-Air Batteries: Synergistic Roles of Li and K Ions in Electrodics.

Tweaking the electrolyte of the anode compartment of zinc-air battery (ZAB) system is shown to be extending the charge-discharge cyclability of the cell. An alkaline zinc (Zn)-air cell working for ∼32 h (192 cycles) without failure is extended to >55 h (>330 cycles) by modifying the anode compartment with a mixture electrolyte of KOH and LiOH. The cell containing the mixture electrolyte has a low overpotential for charging along with high discharge capacity.

Acyclic diaminocarbene-based Thiele, Chichibabin, and Müller hydrocarbons.

Thiele, Chichibabin and Müller hydrocarbons are considered as classical Kekulé diradicaloids. Herein we report the synthesis and characterization of acyclic diaminocarbene (ADC)-based Thiele, Chichibabin, and Müller hydrocarbons. The calculated singlet-triplet energy gaps are Δ = -27.

A Dynamic Chemical Clip in Supramolecular Framework for Sorting Alkylaromatic Isomers using Thermodynamic and Kinetic Preferences.

Adsorptive chemical separation is at the forefront of future technologies, for use in chemical and petrochemical industries. In this process, a porous adsorbent selectively allows a single component from a mixture of three or more chemical components to be adsorbed or permeate. To separate the unsorted chemicals, a different adsorbent is needed.

Efficient symmetry-based γ-encoded DQ recoupling sequences for suppression of t-noise in solid-state NMR spectroscopy at fast MAS.

Solid-state NMR spectroscopy has played a significant role in elucidating the structure and dynamics of materials and biological solids at a molecular level for decades. In particular, the H double-quantum/single-quantum (DQ/SQ) chemical shift correlation experiment is widely used for probing the proximity of protons, rendering it a powerful tool for elucidating the hydrogen-bonding interactions and molecular packing of various complex molecular systems. Two factors, namely, the DQ filtering efficiency and t-noise, dictate the quality of the 2D H DQ/SQ spectra.

Correction: Tethered CAAC-CAAC dimers: oxidation to persistent radical cations and bridging-unit dependent reactivity/stability of the dications.

Correction for 'Tethered CAAC-CAAC dimers: oxidation to persistent radical cations and bridging-unit dependent reactivity/stability of the dications' by Mithilesh Kumar Nayak et al., Chem. Commun.

Cobalt(II)porphyrin-Mediated Selective Synthesis of 1,5-Diketones via an Interrupted-Borrowing Hydrogen Strategy Using Methanol as a C1 Source.

A novel cobalt(II)porphyrin-mediated acceptorless dehydrogenation of methanol is reported for the first time. This methodology has been applied for the coupling of a variety of ketones with methanol to produce 1,5-diketones along with H and HO as the environment friendly byproducts. This paradigm was also demonstrated for a one-pot synthesis of substituted pyridines using a sequential addition protocol where the 1,5-diketones were generated in situ.

Efficient refolding and functional characterization of AMA1(DI+DII) expressed in .

Apical membrane antigen 1 (AMA1) is a surface protein of that plays a crucial role in forming moving junction (MJ) during the invasion of human red blood cells. The obligatory presence of AMA1 in the parasite lifecycle designates this protein as a potential vaccine candidate and an essential target for the development of novel peptide or protein therapeutics. However, due to multiple cysteine residues in the protein sequence, attaining the native fold with correct disulfide linkages during the refolding process after expression in bacteria has remained challenging for years.

Anionic Boron- and Carbon-Based Hetero-Diradicaloids Spanned by a -Phenylene Bridge.

Herein we report the synthesis and characterization of anionic boron- and carbon-based Kekulé diradicaloids spanned by a -phenylene bridge. In contrast to Thiele's hydrocarbon, a closed-shell singlet system, they show an appreciable population of the triplet state at room temperature, as evidenced by both NMR and EPR spectroscopy. Moreover, en route to these anionic boron- and carbon-based hetero-diradicaloids, the formation of an isolable diamino(4-diarylboryl-phenyl)methyl radical was observed.

Graphene oxide-based rechargeable respiratory masks.

Respiratory masks having similar standards of 'N95', defined by the US National Institute for Occupational Safety and Health, will be highly sought after, post the current COVID-19 pandemic. Here, such a low-cost (∼$1/mask) mask design having electrostatic rechargeability and filtration efficiency of >95% with a quality factor of ∼20 kPa is demonstrated. This filtration efficacy is for particles of size 300 nm.

Tethered CAAC-CAAC dimers: oxidation to persistent radical cations and bridging-unit dependent reactivity/stability of the dications.

Herein, we report tethered cyclic(alkyl)(amino)carbene (CAAC) dimers in which two CAAC-motifs are connected by an ethylene-, trans-1,2-cyclohexylene- and propylene-spacer through their N-centres. The 1-electron oxidized radical cations are isolable, whereas a significant influence of the bridging unit on the chemical reactivity becomes apparent in and with the 2-electron oxidized products.

Reactivity of NHC/diphosphene-coordinated Au(I)-hydride.

We report the reactivity of isolable Au(i)-hydride stabilized by an NHC-coordinated diphosphene towards substrates containing C-C and N-N multiple bonds (NHC = N-heterocyclcic carbene). Reactions with dimethyl acetylenedicarboxylate and azobenzene lead to a trans-addition of the Au(i)-H across the C-C triple bond and the N-N double bond, respectively. In contrast, the reaction with ethyl diazoacetate affords a gold(i)-hydrazonide as the 1,1-addition product to the terminal nitrogen atom.

An Unsymmetric Imino-Phosphanamidinate Ligand and its Y(III) Complex: Synthesis, Characterization, and Catalytic Hydroboration of Carbonyl Compounds.

An imino-phosphanamide ligand, [NHIP(Ph)NH-2,6-PrCH] (), containing two different -substituents was prepared by the direct reaction of the lithium salt of -heterocyclic imine (NHI) with phenylchloro-2,6-diisopropylphenyl phosphanamine, PhP(Cl)NH-2,6-Pr-CH. Reaction of with Y(N(SiMe)) afforded the heteroleptic complex, [{L}Y(N(SiMe))] (), by elimination of HN(SiMe). Compound was characterized by multinuclear NMR and X-ray crystallography.

Seven-coordinate Ln complexes assembled from a bulky acacH ligand: their synthesis, structure, photoluminescence and SMM behaviour.

The reaction of a bulky acetyl acetone ligand 1,3-dimesitylpropane-1,3-dione (MesacacH) with hydrated lanthanide chlorides in the presence of tetramethylammonium hydroxide afforded a new family of neutral mononuclear LnIII complexes [Ln(Mesacac)3(DMF)] (Ln = Dy (1); Tb (2); Y0.91Dy0.09 (3); and Er (4)).

Outstanding Broadband (532 nm to 2.2 μm) and Very Efficient Optical Limiting Performance of Some Defect-Engineered Graphenes.

Graphene derivatives and defect-engineered graphenes have attracted the interest of researchers owing to the excellent and tunable properties they exhibit. In this work the optical limiting performance of two defect-engineered boron- and nitrogen-doped reduced graphene oxides is investigated. Both graphenes are found to exhibit exceptional and broadband optical limiting action ranging from 532 to 2200 nm.

α,α'-Diamino--quinodimethanes with Three Stable Oxidation States.

Herein, we report the rational design, synthesis, and characterization of α,α'-diamino-substituted--quinodimethanes, which are a group of partially substituted -quinodimethanes. These exhibit two reversible one-electron redox steps and electrochromism in the ultraviolet, visible, and near-infrared regions. We were able to isolate the crystalline compounds of all three oxidation states: neutral, radical cation, and dication.

Nucleolar size regulates nuclear envelope shape in .

Nuclear shape and size are cell-type specific. Change in nuclear shape is seen during cell division, development and pathology. The nucleus of is spherical in interphase and becomes dumbbell shaped during mitotic division to facilitate the transfer of one nucleus to the daughter cell.

Apolipoprotein E4 exhibits intermediates with domain interaction.

ApoE4(C112R) is the strongest risk factor for Alzheimer's disease, while apoE3(C112) is considered normal. The C112R substitution is believed to alter the interactions between the N-terminal (NTD) and the C-terminal domain (CTD) leading to major functional differences. Here we investigate how the molecular property of the residue at position 112 affects domain interaction using an array of C112X substitutions with arginine, alanine, threonine, valine, leucine and isoleucine as 'X'.

Accuracy of H-H distances measured using frequency selective recoupling and fast magic-angle spinning.

Selective recoupling of protons (SERP) is a method to selectively and quantitatively measure magnetic dipole-dipole interaction between protons and, in turn, the proton-proton distance in solid-state samples at fast magic-angle spinning. We present a bimodal operator-based Floquet approach to describe the numerically optimized SERP recoupling sequence. The description calculates the allowed terms in the first-order effective Hamiltonian, explains the origin of selectivity during recoupling, and shows how different terms are modulated as a function of the radio frequency amplitude and the phase of the sequence.

Electrospun fibers based on carbohydrate gum polymers and their multifaceted applications.

Electrospinning has garnered significant attention in view of its many advantages such as feasibility for various polymers, scalability required for mass production, and ease of processing. Extensive studies have been devoted to the use of electrospinning to fabricate various electrospun nanofibers derived from carbohydrate gum polymers in combination with synthetic polymers and/or additives of inorganic or organic materials with gums. In view of the versatility and the widespread choice of precursors that can be deployed for electrospinning, various gums from both, the plants and microbial-based gum carbohydrates are holistically and/or partially included in the electrospinning solution for the preparation of functional composite nanofibers.

Thermodiffusion-induced traveling and shock waves in a colloidal solution.

The formation of chemical waves in a nonlinear spatially extended system is one of the most fascinating far-from-equilibrium phenomena. An externally imposed thermal gradient in a liquid mixture may induce a concentration gradient generating a thermodynamic cross-flow, which is known as thermal diffusion or the Ludwig-Soret effect. The motion of the components of the mixture is governed by a nonlinear, partial differential equation for the density fraction in space and time.

Dynamic heterogeneity influences the leader-follower dynamics during epithelial wound closure.

Cells of epithelial tissue proliferate and pack together to attain an eventual density homeostasis. As the cell density increases, spatial distribution of velocity and force show striking similarity to the dynamic heterogeneity observed elsewhere in dense granular matter. While the physical nature of this heterogeneity is somewhat known in the epithelial cell monolayer, its biological relevance and precise connection to cell density remain elusive.