Mixed Ionic and Electronic Conductivity in a Tetrathiafulvalene-Phosphonate Metal-Organic Framework.

Mixed ionic-electronic conductors have great potential as materials for energy storage applications. However, despite their promising properties, only a handful of metal-organic frameworks (MOFs) provide efficient pathways for both ion and electron transport. This work reports a proton-electron dual-conductive MOF based on tetrathiafulvalene(TTF)-phosphonate linkers and lanthanum ions.

Sulfur-Functionalized Single-Walled Carbon Nanotube Buckypaper/MTV-BioMetal-Organic Framework Nanocomposites for Gold Recovery.

Developing sustainable, efficient, and selective gold recovery technology is essential to implement the valorization of complementary alternative sources for this precious metal, such as spent e-waste, and to preserve the environment. The main challenge in recovering gold from liquors obtained from leached waste electronics is the low concentration of this precious metal compared to impurities. Here, we report the preparation of a novel multivariate biological metal-organic framework (MTV-BioMOF) as a potential material for the selective recovery of gold metal ions from water, even in the presence of other interfering metals.

BioMOF@PAN Mixed Matrix Membranes as Fast and Efficient Adsorbing Materials for Multiple Heavy Metals' Removal.

Heavy metal ions are a common source of water pollution. In this study, two novel membranes with biobased metal-organic frameworks (BioMOFs) embedded in a polyacrylonitrile matrix with tailored porosity were prepared via nonsolvent induced phase separation methods and designed to efficiently adsorb heavy metal ions from oligomineral water. Under optimized preparation conditions, stable membranes with high MOF loading up to 50 wt % and a cocontinuous sponge-like morphology and a high water permeability of 50-60 L m h bar were obtained.

Selective cycloaddition of ethylene oxide to CO within the confined space of an amino acid-based metal-organic framework.

Host-guest chemistry within the confined space of metal-organic frameworks (MOFs) offers an almost unlimited myriad of possibilities, hardly accessible with other materials. Here we report the synthesis and physical characterization, with atomic resolution by single-crystal X-ray diffraction, of a novel water-stable tridimensional MOF, derived from the amino acid -methyl-L-cysteine, {SrZn[(,)-Mecysmox](OH)(HO)}·9HO (1), and its application as a robust and efficient solid catalyst for the cycloaddition reaction of ethylene/propylene oxide with CO to afford ethylene/propylene carbonate with yields of up to 95% and selectivity of up to 100%. These results nicely illustrate the great potential of MOFs to be game changers for the selective synthesis of industrially relevant products, representing a powerful alternative to the current heterogeneous catalysts.

Degradation of Penicillinic Antibiotics and β-Lactamase Enzymatic Catalysis in a Biomimetic Zn-Based Metal-Organic Framework.

Invited for the cover of this issue are Jesús Ferrando-Soria, Donatella Armentano, Antonio Leyva-Pérez, Emilio Pardo and co-workers at University of Valencia, Technical University of Valencia and University of Calabria. The image depicts the crystal structure of a novel Zn biological metal-organic framework that mimics β-lactamase enzymes. Read the full text of the article at 10.

Degradation of Penicillinic Antibiotics and β-Lactamase Enzymatic Catalysis in a Biomimetic Zn-Based Metal-Organic Framework.

β-Lactam antibiotics are one of the most commonly prescribed drugs to treat bacterial infections. However, their use has been somehow limited given the emergence of bacteria with resistance mechanisms, such as β-lactamases, which inactivate them by degrading their four-membered β-lactam rings. So, a total knowledge of the mechanisms governing the catalytic activity of β-lactamases is required.

Metal-organic frameworks as chemical nanoreactors for the preparation of catalytically active metal compounds.

Since the emergence of metal-organic frameworks (MOFs), a myriad of thrilling properties and applications, in a wide range of fields, have been reported for these materials, which mainly arise from their porous nature and rich host-guest chemistry. However, other important features of MOFs that offer great potential rewards have been only barely explored. For instance, despite the fact that MOFs are suitable candidates to be used as chemical nanoreactors for the preparation, stabilization and characterization of unique functional species, that would be hardly accessible outside the functional constrained space offered by MOF channels, only very few examples have been reported so far.

Metal-Organic Frameworks as Unique Platforms to Gain Insight of σ-Hole Interactions for the Removal of Organic Dyes from Aquatic Ecosystems.

The combination of high crystallinity and rich host-guest chemistry in metal-organic frameworks (MOFs), have situated them in an advantageous position, with respect to traditional porous materials, to gain insight on specific weak noncovalent supramolecular interactions. In particular, sulfur σ-hole interactions are known to play a key role in the biological activity of living beings as well as on relevant molecular recognitions processes. However, so far, they have been barely explored.

Photodegradation of Brilliant Green Dye by a Zinc bioMOF and Crystallographic Visualization of Resulting CO.

We present a novel bio-friendly water-stable Zn-based MOF (), derived from the natural amino acid -serine, which was able to efficiently photodegrade water solutions of brilliant green dye in only 120 min. The total degradation was followed by UV-Vis spectroscopy and further confirmed by single-crystal X-ray crystallography, revealing the presence of CO within its channels. Reusability studies further demonstrate the structural and performance robustness of .

Sequencing of Sequence-Defined Oligourethanes via Controlled Self-Immolation.

Sequence-defined polymers show promise for biomimetics, self-assembly, catalysis, and information storage, wherein the primary structure begets complex chemical processes. Here we report the solution-phase and the high-yielding solid-phase syntheses of discrete oligourethanes and methods for their self-immolative sequencing, resulting in rapid and robust characterization of this class of oligomers and polymers, without the use of MS/MS. Crucial to the sequencing is the inherent reactivity of the terminal alcohol to "unzip" the oligomers, in a controlled and iterative fashion, releasing each monomer as a 2-oxazolidinone.

2-Amino-3'-dialkylaminobiphenyl-based fluorescent intracellular probes for nitric oxide surrogate NO.

Fluorescent probes for nitric oxide (NO), or more frequently for its oxidized surrogate dinitrogen trioxide (NO), have enabled scientists to study the contributions of this signaling molecule to many physiological processes. Seeking to improve upon limitations of other probes, we have developed a family of fluorescent probes based on a 2-amino-3'-dialkylaminobiphenyl core. This core condenses with NO to form benzo[]cinnoline structures, incorporating the analyte into the newly formed fluorophore, which results in product fluorescence with virtually no background contribution from the initial probe.

Improved Xanthone Synthesis, Stepwise Chemical Redox Cycling.

A base-catalyzed direct oxidation of rhodamine, carborhodamine, and siliconrhodamine pyronines to the corresponding xanthones is studied. This methodology utilizes addition of water to split pyronines into xanthone and reduced xanthene, the latter of which is returned to pyronine by oxidation with iodine. The transformation is general, working on the three most recalcitrant versions of N, N, N', N'-tetramethylpyronines in good to excellent yields.

Hydrogen peroxide production via a redox reaction of N,N'-dimethyl-2,6-diaza-9,10-anthraquinonediium by addition of bisulfite.

We demonstrate that bisulfite can be used for reduction of a highly electrophilic anthraquinone derivative, N,N'-dimethyl-2,6-diaza-9,10-anthraquinonediium (DAAQ), and subsequent autoxidation generates an equivalent of hydrogen peroxide. The mechanism for DAAQ reduction by bisulfite, DAAQ electrochemistry, and use of a simple test strip assay for H2O2, are described.

A Versatile Approach to Noncanonical, Dynamic Covalent Single- and Multi-Loop Peptide Macrocycles for Enhancing Antimicrobial Activity.

Peptide oligomers offer versatile scaffolds for the formation of potent antimicrobial agents due to their high sequence versatility, inherent biocompatibility, and chemical tunability. Though many methods exist for the formation of peptide-based macrocycles (MCs), increasingly pervasive in commercial antimicrobial therapeutics, the introduction of multiple looped structures into a single peptide oligomer remains a significant challenge. Herein, we report the utilization of dynamic hydrazone condensation for the versatile formation of single-, double-, and triple-loop peptide MCs using simple dialdehyde or dihydrazide small-molecule cross-linkers, as confirmed by MALDI-TOF MS, HPLC, and SDS-PAGE.

Synthesis and properties of Asante Calcium Red--a novel family of long excitation wavelength calcium indicators.

Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450-540 nm) excitation with deep-red fluorescence (640 nm).

Risk of underdiagnosing amebic dysentery due to false-negative Entamoeba histolytica antigen detection.

Entamoeba histolytica antigen assays on stool are widely used to diagnose amebiasis. We report a case of confirmed amebic colitis with a false-negative antigen detection that became positive after treatment. Our results indicate that these assays may underdiagnose acute amebic infection when used alone and should be used cautiously.