Graphitic carbon nitride derived probes for the recognition of heavy metal pollutants of environmental concern in water bodies.

Graphitic carbon nitride (g-CN) has a number of valuable features that have been recognized during the studies related to its photocatalytic activity enhancement derived by visible light. Because of these characteristics, g-CN can be used as a detecting signal transducer with different transmission modalities. The latest up-to-date detection capabilities of modified g-CN nanoarchitectures are covered in this study.

Synthesis of Chiral 2,3-Dihydrofurans via One-Pot Pd-Catalyzed Asymmetric Allylic Cycloaddition and a Retro-Dieckmann Fragmentation Cascade.

An efficient method for the enantioselective synthesis of 2,3-dihydrofurans bearing a quaternary stereocenter has been developed via Pd-catalyzed asymmetric allylic cycloaddition and a retro-Dieckmann Fragmentation cascade. The asymmetric allylic cycloaddition of vinylethylene carbonates with 3-cyanochromone followed by base-assisted retro-Dieckmann fragmentation proceeded smoothly via a one-pot process to produce chiral 3,4-disubstituted 2,3-dihydrofurans in high yields with excellent enantioselectivities.

Organic Covalent Interaction-based Frameworks as Emerging Catalysts for Environment and Energy Applications: Current Scenario and Opportunities.

The term "covalent organic framework" (COF) refers to a class of porous organic polymeric materials made from organic building blocks that have been covalently bonded. The preplanned and predetermined bonding of the monomer linkers allow them to demonstrate directional flexibility in two- or three-dimensional spaces. COFs are modern materials, and the discovery of new synthesis and linking techniques has made it possible to prepare them with a variety of favorable features and use them in a range of applications.

Graphitic carbon nitride nanosheets as promising candidates for the detection of hazardous contaminants of environmental and biological concern in aqueous matrices.

Monitoring of pollutant and toxic substances is essential for cleaner environment and healthy life. Sensing of various environmental contaminants and biomolecules such as heavy metals, pharmaceutics, toxic gases, volatile organic compounds, food toxins, and pathogens is of high importance to guaranty the good health and sustainable environment to community. In recent years, graphitic carbon nitride (g-CN) has drawn a significant amount of interest as a sensor due to its large surface area and unique electrochemical properties, low bandgap energy, high thermal and chemical stability, facile synthesis, nontoxicity, and electron rich property.

Recent Advances in the Catalytic Asymmetric Friedel-Crafts Reactions of Indoles.

Functionalized chiral indole derivatives are privileged and versatile organic frameworks encountered in numerous pharmaceutically active agents and biologically active natural products. The catalytic asymmetric Friedel-Crafts reaction of indoles, catalyzed by chiral metal complexes or chiral organocatalysts, is one of the most powerful and atom-economical approaches to access optically active indole derivatives. Consequently, a wide range of electrophilic partners including α,β-unsaturated ketones, esters, amides, imines, β,γ-unsaturated α-keto- and α-ketiminoesters, ketimines, nitroalkenes, and many others have been successfully employed to achieve a plethora of functionalized chiral indole moieties.

The Semantics of the Preposition " " in the Quran: A Conceptual Metaphor Perspective.

Traditional syntactic approaches do not offer a plausible explanation regarding the use of the Arabic preposition " " with abstract nouns or states. This article adopts a corpus-based approach to investigate the semantic classification of the preposition " " in the Quran from a cognitive linguistic perspective. Conceptual metaphor theory (hereafter CMT) was employed to find out conceptual metaphors (hereafter CM) in the data retrieved from the Quran with the help of search Quran software.

Pd-Catalyzed regio- and stereoselective allylic substitution of vinylethylene carbonates with 1,2,4-triazoles.

-Substituted 1,2,4-triazoles are ubiquitous skeletons in medicinal agents, agrochemicals, and organic materials. Herein, an efficient and practical method for the synthesis of -allylated 1,2,4-triazoles Pd-catalyzed allylic substitution of vinylethylene carbonates (VECs) with 1,2,4-triazoles has been developed. By using a catalyst generated from Pd(dba)·CHCl and DPPE under mild conditions, the process allows rapid access to -allylated 1,2,4-triazoles bearing diverse functionalities in high yields with excellent -selectivities, linear-selectivities, and -stereoselectivities.

Covalent Organic Frameworks-Based Membranes as Promising Modalities from Preparation to Separation Applications: An Overview.

Covalent organic frameworks (COFs) are a promising class of porous crystalline materials made up of covalently connected and periodically protracted network topologies through organic linkers. The tailorability of organic linker and intrinsic structures endow COFs with a tunable porosity and structure, low density, facilely-tailored functionality, and large surface area, attracting increasing amount of interests in variety of research areas of membrane separations. COF-based membranes have spawned a slew of new research projects, ranging from fabrication methodologies to separation applications.

Asymmetric Allylic Etherification of Vinylethylene Carbonates with Diols via Pd/B Cooperative Catalysis: A Route to Chiral Hemi-Crown Ethers.

Pd-catalyzed regio- and enantioselective allylic etherification of vinylethylene carbonates (VECs) with diols has been developed. By using cooperative catalysts of the chiral palladium complex and triethylborane in mild conditions, the process gave monoetherified and bisetherified polyglycol derivatives with tetrasubstituted stereocenters in high yields with complete regioselectivities and high levels of enantio- and diastereoselectivities.

Pd-Catalyzed regio- and enantioselective allylic substitution with 2-pyridones.

An efficient method for the asymmetric synthesis of N-substituted 2-pyridones via Pd-catalyzed regio- and enantioselective allylic substitution of hydroxyl-containing allylic carbonates with 2-pyridones has been developed. By using a palladium complex in situ generated from Pd2(dba)3·CHCl3 and phosphoramidite L2 as a ligand, the process allowed rapid access to N-substituted 2-pyridones with complete chemo- and regioselectivities and good to high enantioselectivities.

Pd-Catalyzed Asymmetric Allylic Cycloaddition of Vinyloxetanes with Formaldehyde.

An efficient method for the enantioselective construction of tertiary 1,3-diols via Pd-catalyzed asymmetric allylic cycloaddition of vinyloxetanes with an abundant feedstock, formaldehyde, is developed. Using the palladium complex generated in situ from Pd(dba)·CHCl and phosphoramidite L3 as a catalyst under mild conditions, the process allows one to convert racemic 2-substituted 2-vinyloxetanes (1) to the corresponding 1,3-dioxanes (2) as methylene acetal protected tertiary 1,3-diols in high yields with good to excellent enantioselectivities.

Enantioselective Construction of Tertiary C-O Bond via Allylic Substitution of Vinylethylene Carbonates with Water and Alcohols.

An efficient method for the enantioselective construction of tertiary C-O bond via asymmetric allylic substitution of racemic vinylethylene carbonates with water and alcohols has been developed. Under the cooperative catalysis system of an in situ generated chiral palladium complex and boron reagent in mild conditions, the process allowed rapid access to valuable tertiary alcohols and ethers in high yields with complete regioselectivities and high enantioselectivities. This protocol represented the first example of direct enantioselective formation of a tertiary C-O bond with water as an oxygen donor.