SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Chemical communications (Cambridge, England)

30

Carbapenems, ‘last resort’ antibiotics for many bacterial infections, can now be broken down by several class A β-lactamases (i.e. carbapenemases). Here, carbapenemase activity is predicted through QM/MM dynamics simulations of acyl-enzyme deacylation, requiring only the 3D structure of the apo-enzyme. This may assist in anticipating resistance and future antibiotic design.

Concepts: Microorganism, Infection, Antibiotic, Clostridium difficile, Antibiotic resistance, Virus, Penicillin, Bacteria

29

Solar photoelectrosynthesis of methanol was driven on hybrid CuO-Cu(2)O semiconductor nanorod arrays for the first time at potentials ∼800 mV below the thermodynamic threshold value and at Faradaic efficiencies up to ∼95%. The CuO-Cu(2)O nanorod arrays were prepared on Cu substrates by a two-step approach consisting of the initial thermal growth of CuO nanorods followed by controlled electrodeposition of p-type Cu(2)O crystallites on their walls. No homogeneous co-catalysts (such as pyridine, imidazole or metal cyclam complexes) were used contrasting with earlier studies on this topic using p-type semiconductor photocathodes. The roles of the core-shell nanorod electrode geometry and the copper oxide composition were established by varying the time of electrodeposition of the Cu(2)O phase on the CuO nanorod core surface.

Concepts: Germanium, Copper(II) oxide, P-type semiconductor, Semiconductor, Copper, Carbon dioxide, Oxide, Oxygen

28

A series of novel triazinonide-bridged bisimidazolium pincers were easily synthesized by quaternization of functionalized N-phenylimidazoles with highly reactive cyanuric chloride under mild conditions. The pincer was proven to be a very efficient ligand for in situ Pd-catalyzed Suzuki-Miyaura reaction with ppm-level catalyst loading.

Concepts: Stille reaction, Denticity, Cyanuric acid, Carcinoma in situ, Cyanuric chloride, In situ, Ligand

28

The use of carbon dioxide as a renewable and environmentally friendly source of carbon is highly attractive. A novel and efficient protocol for the synthesis of phenolic compounds from carbonyl compounds and carbon dioxide in the presence of a catalytic amount of Pd(OAc)(2) has been developed. This reaction is appealing for industries and is a tool for the sequestration of carbon dioxide.

Concepts: Carbonyl sulfide, Chemical reaction, Carbonyl, Carbon dioxide, Redox, Carbon monoxide, Carbon, Oxygen

28

Triazolylidenes have rapidly emerged as a powerful subclass of N-heterocyclic carbene ligands for transition metals. They are readily available through regioselective [2 + 3] cycloaddition of alkynes and azides and subsequent metallation according to procedures established for related carbenes. Due to their mesoionic character, triazolylidenes are stronger donors than Arduengo-type imidazol-2-ylidenes. Spurred by these attractive attributes and despite their only recent emergence, triazolylidenes have shown major implications in catalysis. This feature article summarises the synthetic accessibility of triazolylidene metal complexes and their electronic and structural characteristics, and it compiles their applications, in particular, as catalyst precursors for various bond forming and redox reactions, as well as first approaches into photophysical and biochemical domains.

Concepts: Zinc, Persistent carbene, Nitrogen, Hydrogenation, Iron, Carbene, Chemical reaction, Hydrogen

28

Rlyso, a highly selective and sensitive pH sensor, can stain lysosomes with a novel lysosome-locating group, methylcarbitol. Rlyso was successfully used to detect lysosomal pH changes during apoptosis or induced by chloroquine while avoiding the “alkalizing effect” on lysosomes of current lysosomal probes with nitrogen-containing sidechains.

Concepts: PH, Lysosome, Phagocytosis, Vesicle

28

Ordered ultrathin films based on alternate assembly of CdTe QDs and layered double hydroxide monolayers have been fabricated, which can be used as a photoluminescence temperature sensor with dual-parameter signals and high response sensitivity.

Concepts: Hydroxides, Sensor

28

We report the analysis of a novel terpyridine based supramolecular hydrogel which shows fluorescent properties in the gel but not in the sol form; the gel forms in a narrow pH range in aqueous solutions specifically in the presence of sodium ions, and contains between 98% and 99.2% water.

Concepts: Aristotle, Potassium, Physical chemistry, Colloid, Sodium, Concentration, Solutions, Chemistry

28

Urea-based molecular constructs are shown for the first time to be nonlinear optically (NLO) active in solution. We demonstrate self-assembly triggered large amplification and specific anion recognition driven attenuation of the NLO activity. This orthogonal modulation along with an excellent nonlinearity-transparency trade-off makes them attractive NLO probes for studies related to weak self-assembly and anion transportation by second harmonic microscopy.

Concepts: Acoustics, Optical rotation, Physical chemistry, Atom, Chemistry, Telecommunication, Optics, Optical fiber

28

Novel ruthenium(ii) complexes were obtained as a result of a stoichiometric reaction of Grubbs' benzylidene second generation catalysts with 3-nitropropene. These stable complexes, formally ruthenaisoxazole N-oxide derivatives, display activity in both metathesis and non-metathetic processes such as cycloisomerisation, isomerisation and transfer hydrogenation.

Concepts: Catalysis, Chemical equilibrium, Chemical reaction, Hydrogen, Richard R. Schrock, Hydrogenation, Alkene, Olefin metathesis