Bi5O7I/g-C3N4 Heterostructures With Enhanced Visible-Light Photocatalytic Performance for Degradation of Tetracycline Hydrochloride

Bi5O7I/g-C3N4 p-n junctioned photocatalysts were synthesized by alcohol-heating and calcination in air. The structures, morphologies and optical properties of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy (DRS). Photocatalytic activity of the heterojunctioned composites were evaluated by degradation of Rhodamine B (RhB) and tetracycline hydrochloride (TCH) under visible light illumination. The results indicated that the composites exhibited superior efficiencies for photodegradation of RhB and TCH in comparison with pure BiOI, Bi5O7I and g-C3N4. An effective built-in electric field was formed by the interface between p-type Bi5O7I and n-type g-C3N4, which promoted the efficient separation of photoinduced electron-hole pairs. In addition, 8% Bi5O7I/g-C3N4 composite showed excellent photostability in a five-cycle photocatalytic experiment. Experiments on scavenging active intermediates revealed the roles of active species.

Design, Synthesis and Antibacterial Activity screening of Novel Bis cyclic Imides Linked to Trimethoprim Drug

Cyclic imides are well known important organic compounds that exhibit diverse biological activities like anti - inflammatory, antibacterial, analgesic, hypoglycemic and antifungal activities. Besides these compounds are useful building blocks in the synthesis of many drugs and pharmaceuticals. On the other hand trimethoprim is a well-known antibiotic that is used in combination with Sulfamethoxazole in treating urinary tract infections, bacterial infections and acute invasive diarrhea. Moreover Schiff bases represent the most active intermediates that exhibit wide spectrum of biological activities and play a vital role in the production of different pharmaceutical and bioactive heterocycles. Based on all these facts, it seems worthwhile to design and synthesize new molecules that contain these three active moieties (cyclic imide, trimethoprim and Schiff base) together in the same molecule since this may exhibit the new compounds high biological activity and may open possibilities for fighting bacterial infections.

The ability of the natural chemoprophylactic agent curcumin to function as an effective UV photosensitiser

It is known that some plant polyphenols and alkaloids can act as effective photosensitisers of UV radiation. This phenomenon can enhance both therapeutic and side effects. Since there is no information regarding curcuminoids on their ability to function as UV photosensitisers, this work investigated the effect of UV radiation on the cytotoxic effect of curcumin, as well as its nanostructured forms, against keratinocytes of the HaCaT line and cancer cells MDA-MB-231. The results obtained indicate that curcumin is an effective photosensitiser capable of initiating photochemical reactions under the influence of UV radiation of the A and B range, which lead to the formation of chemically active intermediates, disruption of membrane integrity and cell death. When curcumin is incorporated into nanostructures based on polyallylamine hydrochloride /polystyrene sulfate and chitosan /dextran sulfate, its ability to function as a UV photosensitiser is retained.

Pyrimidine Biosynthetic Enzyme CAD: Its Function, Regulation, and Diagnostic Potential

CAD (Carbamoyl-phosphate synthetase 2, Aspartate transcarbamoylase, and Dihydroorotase) is a multifunctional protein that participates in the initial three speed-limiting steps of pyrimidine nucleotide synthesis. Over the past two decades, extensive investigations have been conducted to unmask CAD as a central player for the synthesis of nucleic acids, active intermediates, and cell membranes. Meanwhile, the important role of CAD in various physiopathological processes has also been emphasized. Deregulation of CAD-related pathways or CAD mutations cause cancer, neurological disorders, and inherited metabolic diseases. Here, we review the structure, function, and regulation of CAD in mammalian physiology as well as human diseases, and provide insights into the potential to target CAD in future clinical applications.

Chemodivergent assembly of ortho-functionalized phenols with tunable selectivity via rhodium(III)-catalyzed and solvent-controlled C-H activation

Ortho-functionalized phenols and their derivatives represent prominent structural motifs and building blocks in medicinal and synthetic chemistry. While numerous synthetic approaches exist, the development of atom-/step-economic and practical methods for the chemodivergent assembly of diverse ortho-functionalized phenols based on fixed catalyst/substrates remains challenging. Here, by selectively controlling the reactivities of different sites in methylenecyclopropane core, Rh(III)-catalyzed redox-neutral and tunable C-H functionalizations of N-phenoxyacetamides are realized, providing access to both ortho-functionalized phenols bearing linear dienyl, cyclopropyl or allyl ether groups, and cyclic 3-ethylidene 2,3-dihydrobenzofuran frameworks under mild cross-coupling conditions. These divergent transformations feature broad substrate compatibility, synthetic applications and excellent site-/regio-/chemoselectivity. Experimental and computational mechanistic studies reveal that distinct catalytic modes involving selective β-C/β-H elimination, π-allylation, inter-/intramolecular nucleophilic substitution cascade and β-H’ elimination processes enabled by different solvent-mediated and coupling partner-controlled reaction conditions are crucial for achieving chemodivergence, among which a structurally distinct Rh(V) species derived from a five-membered rhodacycle is proposed as the corresponding active intermediates.

Pressure-promoted highly-ordered Fe-doped-Ni2B for effective oxygen evolution reaction and overall water splitting

Accurate doping at special atomic sites can achieve effective control of active centers for the oxygen evolution reaction (OER), leading to the synthesis of active intermediates with higher conversion efficiency.

Trifluoromethanesulfonamide vs. Non-Fluorinated Sulfonamides in Oxidative Sulfamidation of the C=C Bond: An In Silico Study

A theoretical analysis of the reaction of oxidative sulfamidation of several alkenes was performed in order to explain the various experimental observations and different reactivity of triflamide and non-fluorinated sulfonamides. Transformations occurring in the system alkene–sulfonamide in the presence of oxidative system (ButOCl + NaI) were analyzed at the MP2/DGDZVP//B3LYP/DGDZVP level of theory using the IEF-PCM method for taking into account the solvent acetonitrile (MeCN) effect. As the model substrates, styrene, trimethyl(vinyl)silane, dimethyl(divinyl)silane and diphenyl(divinyl)silane were chosen and mesylamide, triflamide, tosylamide and p-nosylamide were taken as the reagents. ButOI generated from ButOCl and NaI reacts with sulfonamides to give N-iodinated sulfonamides RSO2NHI and RSO2NI2 as active intermediates, the iodinating activity of the latter being notably higher. The analysis allowed to answer such challenging questions as different reactivity of nonfluorinated sulfonamides leading to aziridination and of triflamide resulting in the formation the main products of bis-triflamidation, or different regioselectivity of halogenation of styrene and trimethyl(vinyl)silane caused by a linear intermediate iodonium cation in the former case and a cyclic one in the latter.