Zero-Dimensional Hybrid Organic-Inorganic Indium Bromide with Blue Emission.

Low-dimensional hybrid organic-inorganic metal halides have received increased attention because of their outstanding optical and electronic properties. However, the most studied hybrid compounds contain lead and have long-term stability issues, which must be addressed for their use in practical applications. Here, we report a new zero-dimensional hybrid organic-inorganic halide, RInBr, featuring photoemissive trimethyl(4-stilbenyl)methylammonium (R) cations and nonemissive InBr tetrahedral anions.

PEGylation of Polyethylenimine Lowers Acute Toxicity while Retaining Anti-Biofilm and β-Lactam Potentiation Properties against Antibiotic-Resistant Pathogens.

Bacterial biofilms, often impenetrable to antibiotic medications, are a leading cause of poor wound healing. The prognosis is worse for wounds with biofilms of antimicrobial-resistant (AMR) bacteria, such as methicillin-resistant (MRSA), methicillin-resistant (MRSE), and multi-drug resistant (MDR-PA). Resistance hinders initial treatment of standard-of-care antibiotics.

Broadband Emission in Hybrid Organic-Inorganic Halides of Group 12 Metals.

We report syntheses, crystal and electronic structures, and characterization of three new hybrid organic-inorganic halides (R)ZnBr(DMSO), (R)CdBr·DMSO, and (R)CdI(DMSO) (where (R) = C(CH)CHN(CH), and DMSO = dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals and bulk polycrystalline powders using a DMSO-methanol solvent system. On the basis of the single-crystal X-ray diffraction results carried out at room temperature and 100 K, all compounds have zero-dimensional (0D) crystal structures featuring alternating layers of bulky organic cations and molecular inorganic anions based on a tetrahedral coordination around group 12 metal cations.

Improved Performance of Glucose Bioanodes Using Composites of (7,6) Single-Walled Carbon Nanotubes and a Ferrocene-LPEI Redox Polymer.

The effect of incorporating different types of carbon nanotubes into composite films of a redox polymer (FcMe-C-LPEI) and glucose oxidase (GOX) was investigated. The composite films were constructed by first forming a high-surface area network film of either single-walled carbon nanotubes (SWNTs) or multiwalled carbon nanotubes (MWNTs) on a glassy carbon electrode (GCE) by solution casting of a suspension of Triton-X-100 dispersed SWNTs. Next a glucose responsive redox hydrogel was formed on top of the nanotube-modified electrode by cross-linking FcMe-C-LPEI with glucose oxidase via ethylene glycol diglycidyl ether (EGDGE).

Efficacy of ampicillin against methicillin-resistant Staphylococcus aureus restored through synergy with branched poly(ethylenimine).

β-Lactam antibiotics kill Staphylococcus aureus bacteria by inhibiting the function of cell wall penicillin-binding proteins (PBPs) 1 and 3. However, β-lactams are ineffective against PBP2a, used by methicillin-resistant S. aureus (MRSA) to perform essential cell wall crosslinking functions.

Electrochemical Characterization of Layer-By-Layer Assembled Ferrocene-Modified Linear Poly(ethylenimine)/Enzyme Bioanodes for Glucose Sensor and Biofuel Cell Applications.

Ferrocenylhexyl- and ferrocenylpropyl-modified linear poly(ethylenimine) (Fc-C6-LPEI, Fc-C3-LPEI) were used with periodate-modified glucose oxidase (p-GOX) in the layer-by-layer assembly of enzymatic bioanodes on gold. Fc-C6-LPEI/p-GOX and Fc-C3-LPEI/p-GOX films of 16 bilayers were capable of generating up to 381 ± 3 and 1417 ± 63 μA cm(-2), respectively, in response to glucose. These responses are greater than those of analogous bioanodes fabricated using conventional cross-linking techniques and are extremely high for planar, low surface area, single-enzyme electrodes.

Line of Dirac Nodes in Hyperhoneycomb Lattices.

We propose a family of structures that have "Dirac loops," closed lines of Dirac nodes in momentum space, on which the density of states vanishes linearly with energy. Those lattices all possess the planar trigonal connectivity present in graphene, but are three dimensional. We show that their highly anisotropic and multiply connected Fermi surface leads to quantized Hall conductivities in three dimensions for magnetic fields with toroidal geometry.

Application of the compensated Arrhenius formalism to explain the dielectric constant dependence of rates for Menschutkin reactions.

The dependence of the reaction rate on solvent dielectric constant is examined for the reaction of trihexylamine with 1-bromohexane in a series of 2-ketones over the temperature range 25-80 °C. The rate constant data are analyzed using the compensated Arrhenius formalism (CAF), where the rate constant assumes an Arrhenius-like equation that also contains a dielectric constant dependence in the exponential prefactor. The CAF activation energies are substantially higher than those obtained using the simple Arrhenius equation.

Effect of surfactant type and redox polymer type on single-walled carbon nanotube modified electrodes.

Electrodes modified with single-walled carbon nanotubes (SWNTs) offer a number of attractive properties for developing novel electrochemical sensors. A common method to immobilize SWNTs onto the electrode surface is by placing a droplet of a SWNT suspension onto the electrode surface and allowing the solvent to evaporate. In order to maximize the properties of individual SWNTs, surfactants are normally present in these suspensions to provide stable and homogeneous SWNT dispersions.

Layer-by-layer assembly of ferrocene-modified linear polyethylenimine redox polymer films.

Herein, both electrostatic and covalent layer-by-layer assembly were used for the construction of multicomposite thin films using a ferrocene-modified linear poly(ethylenimine) redox polymer (Fc-C6-LPEI) as the cationic polyelectrolye, and poly(acrylic acid) (PAA), poly(glutamic acid) (PGA), or glucose oxidase (GOX) as the negative polyelectrolyte. The assembly of the multilayer films was characterized by cyclic voltammetry (CV), UV/Vis spectroscopy, and ellipsometry with the enzymatic response of the films containing GOX being characterized via constant potential amperometry. CV measurements suggested that the successful buildup of multilayer films was dependent upon the nature of the anionic polyelectrolyte used.

Mass and charge transport in cyclic carbonates: implications for improved lithium ion battery electrolytes.

The compensated Arrhenius formalism (CAF) is applied to conductivity and diffusion data for a family of cyclic carbonates composed of octylene carbonate, decylene carbonate, undecylene carbonate, and dodecylene carbonate. The strong intermolecular interactions in these liquids lead to diffusion activation energies that are higher than those for typical aprotic solvents. The conductivity results show that activation energies are similar between TbaTf and LiTf cyclic carbonate electrolytes.

Molecular and system parameters governing mass and charge transport in polar liquids and electrolytes.

Onsager's model of the dielectric constant is used to provide a molecular-level picture of how the dielectric constant affects mass and charge transport in organic liquids and organic liquid electrolytes. Specifically, the molecular and system parameters governing transport are the molecular dipole moment μ and the solvent dipole density N. The compensated Arrhenius formalism (CAF) writes the temperature-dependent ionic conductivity or diffusion coefficient as an Arrhenius-like expression that also includes a static dielectric constant (ε(s)) dependence in the exponential prefactor.

Incorporation of single-walled carbon nanotubes into ferrocene-modified linear polyethylenimine redox polymer films.

In this study, we describe the effects of incorporating single-walled carbon nanotubes (SWNTs) into redox polymer-enzyme hydrogels. The hydrogels were constructed by combining the enzyme glucose oxidase with a redox polymer (Fc-C(6)-LPEI) in which ferrocene was attached to linear poly(ethylenimine) by a six-carbon spacer. Incorporation of SWNTs into these films changed their morphology and resulted in a significant increase in the enzymatic response at saturating glucose concentrations (3 mA/cm(2)) as compared to films without SWNTs (0.

High-sensitivity amperometric biosensors based on ferrocene-modified linear poly(ethylenimine).

Amperometric biosensors for glucose and hydrogen peroxide have been built by immobilizing glucose oxidase (GOX) and horseradish peroxidase (HRP) in cross-linked films of ferrocene-modified linear poly(ethylenimine). At pH 7, the glucose sensors generated limiting catalytic current densities of 1.2 mA/cm2.

Effects of electrolyte and pH on the behavior of cross-linked films of ferrocene-modified poly(ethylenimine).

Ferrocene redox polymers based on the coupling of ferrocenecarboxaldehyde to both linear and branched poly(ethylenimine) (PEI) have been prepared to investigate the effects of pH, electrolyte, and cross-linking on electron charge transport and film swelling. The redox behavior of both ferrocene-modified linear PEI and ferrocene-modified branched PEI was investigated by cyclic voltammetry, while electron diffusion coefficients reported for PEI-based redox polymers were determined by electrochemical impedance spectroscopy. In phosphate solutions at pH>7, cross-linked films of both redox polymers exhibited multiple redox wave behavior and were unstable.

Conversion of N-aromatic amides to O-aromatic esters.

[reaction: see text] N-Aromatic secondary amides can be transformed into O-aromatic esters in high yield via N-nitrosamide intermediates. The amides can be generated in situ from the corresponding aromatic amines or nitro compounds, and phenols can easily be made from the esters. The reaction can be modified by addition of methyl methacrylate or toluene at 0 degrees C to give polymerization or deamination, respectively.