The synergistic triad of graphene quantum dots, polymer, and ferrites for the photodegradation of dyes in aqueous solution.

This work aimed to investigate photocatalytic properties of GQDs@PEG@Mg-ZnFeO nanocomposite, composed of graphene quantum dots (GQDs), polyethylene glycol (PEG), and Mg-ZnFeO, for the degradation of methylene blue (MB) and crystal violet (CV). This nanocomposite was synthesized using facile ultrasonics-assisted methodology. XRD analysis confirmed the formation of the spinel structure of the Mg-ZnFeO in the nanocomposite, whereas the presence of GQDs and PEG was confirmed by Fourier transform infrared spectroscopy.

The green synthesis of magnesium oxide nanocomposite-based solid phase for the extraction of arsenic, cadmium, and lead from drinking water.

Solid-phase extraction (SPE) has attracted the attention of scientists because it can increase the selectivity and sensitivity measurements of analytes. Therefore, this study is designed to synthesise magnesium oxide nanoparticles (D-MgO-NPs) by an eco-friendly method using biogenic sources followed by fabricating its chitosan-based polymeric composite (D-MgO-NC) for the SPE of heavy metals (HMs), , arsenic (As), cadmium (Cd), and lead (Pb) from drinking water. Various analytical techniques were used for the surface characterization of D-MgO-NPs and D-MgO-NC.

Nickel-Catalyzed Enantioconvergent Carboxylation Enabled by a Chiral 2,2'-Bipyridine Ligand.

In contrast to previous approaches to chiral α-aryl carboxylic acids that based on reactions using hazardous gases, pressurized setup and mostly noble metal catalysts, in this work, a nickel-catalyzed general, efficient and highly enantioselective carboxylation reaction of racemic benzylic (pseudo)halides under mild conditions using atmospheric CO has been developed. A unique chiral 2,2'-bipyridine ligand named Me-SBpy featuring compact polycyclic skeleton enabled both high reactivity and stereoselectivity. The utility of this method has been demonstrated by synthesis of various chiral α-aryl carboxylic acids (30 examples, up to 95 % yield and 99 : 1 er), including profen family anti-inflammatory drugs and transformations using the acids as key intermediates.

Synthesis of Axially Chiral Biaryls via Enantioselective Ullmann Coupling of ortho-Chlorinated Aryl Aldehydes Enabled by a Chiral 2,2'-Bipyridine Ligand.

The first nickel-catalyzed highly enantioselective reductive Ullmann coupling of ortho-chlorinated aryl aldehyde was achieved under mild reaction conditions with a chiral 2,2'-bipyridine ligand (+)-DTB-SBpy, thus providing axially chiral biphenyl or binaphthyl dials with up to 99 % yield and 99.5:0.5 er.

Design and Synthesis of Tunable Chiral 2,2'-Bipyridine Ligands: Application to the Enantioselective Nickel-Catalyzed Reductive Arylation of Aldehydes.

A new class of chiral 2,2'-bipyridine ligands, SBpy, featuring minimized short-range steric hindrance and structural tunability was rationally designed and developed, and the effectiveness was demonstrated in the first highly enantioselective Ni-catalyzed addition of aryl halides to aldehydes. In comparison with known approaches using preformed aryl metallic reagents, this reaction is more step-economical and functional group tolerant. The reaction mechanism and a model of stereocontrol were proposed based on experimental and computational results.

Well-Defined, Versatile and Recyclable Half-Sandwich Nickelacarborane Catalyst for Selective Carbene-Transfer Reactions.

Catalytic carbene-transfer reactions constitute a class of highly useful transformations in organic synthesis. Although catalysts based on a range of transition-metals have been reported, the readily accessible nickel(II)-based complexes have been rarely used. Herein, an air-stable nickel(II)-carborane complex is reported as a well-defined, versatile and recyclable catalyst for selective carbene transfer reactions with low catalyst loading under mild conditions.

Enantioselective intermolecular all-carbon [4+2] annulation via N-heterocyclic carbene organocatalysis.

The highly stereoselective intermolecular all-carbon [4+2] annulation between in situ generated acyclic dienolates and α,β-unsaturated acyl azoliums is disclosed. The identification of 2-acyloxy-3-butenones as suitable diene precursors is the key to the success of this transformation. The corresponding highly functionalized cyclohexene products, which are inaccessible from Diels-Alder reactions, were delivered with high levels of diastereo- and enantioselectivities.

Enantioselective Synthesis of 1,2-Dihydronaphthalenes via Oxidative N-Heterocyclic Carbene Catalysis.

1,2-Dihydronaphthalenes are important molecules in both medicinal and synthetic chemistry, but methods for the catalytic asymmetric construction of this class of molecules are limited. The diastereo- and enantioselective N-heterocyclic carbene-catalyzed cascade annulation reactions using benzodiketones and enals under oxidative conditions, which afford a variety of 1,2-dihydronaphthalenes with two adjacent stereocenters in up to 99% yield, with >20:1 dr, and up to 99% ee, are reported. Furthermore, the product can be easily transformed to a series of useful compounds such as alcohol, amide, and epoxide.

Gorlin-Goltz syndrome.

A 12 years old girl was presented with bilateral swellings on angle and body of mandible. On general physical examination, there were polydactyly and papular lesions on arm. Histopathology of mandibular lesions revealed odontogenic keratocysts.