A polyfunctionalized carbon framework composite for efficient decontamination of Cr(VI) and polycyclic aromatic nitrides from acidic wastewater.

Developing multifunctional engineered adsorbents is an effective strategy for decontaminating the environment from various pollutants. In this study, a polyfunctionalized carbon-framework composite, MSC-CFM, was synthesized. The composite comprises an aromatic carbon framework enriched with various functional groups, including magnetic nanoparticles, hydroxyl, and amino groups. MSC-CFM was used to decontaminate Cr(VI) and polycyclic aromatic nitrides (p-dimethylaminoazobenzene sulfonate (DAS) and diphenyl-4, 4 '-di [sodium (azo-2 -) -1-amino-naphthalene-4-sulfonate] (DANS)) from acidic wastewater. The adsorption capacities of MSC-CFM for Cr(VI), DAS and DANS, quantified using the Langmuir isotherm model, were 161.28, 310.83, and 1566.09 mg/g, respectively. Cr(VI) and PAHs (DAS and DANS) were monolayer adsorbed controlled by chemisorption. MSC-CFM could maintain good adsorption efficiency after up to 6 adsorption and desorption cycles. The presence of polycyclic aromatic nitrides promoted the adsorption of Cr(VI) in the Cr(VI)-DAS/DANS binary systems. Removal of pollutants by MSC-CFM involved a variety of unreported reaction mechanisms, such as electrostatic attraction, redox reaction, anion exchange, intermolecular hydrogen bonding, complexation reaction, π-π interaction, and anion-π interaction. MSC-CFM, enriched with a variety of functional groups, is a promising new material for environmental protection. It has good potential for practical application in treating polluted wastewater.

Asymmetric Formal [3 + 2]-Cycloaddition of Azomethine Imines with Azlactones To Synthesize Bicyclic Pyrazolidinones.

An efficient enantioselective formal [3 + 2]-cycloaddition of azomethine imines with azlactones has been realized by using a chiral bifunctional bisguanidinium hemisalt as the catalyst. Optically active bicyclic pyrazolidinone compounds were generated under mild reaction conditions in high yields (up to 99%) with good dr (up to 88:12) and excellent ee values (up to 99%). This simple and efficient strategy provides a method to construct biologically important chiral tetrahydropyrazolo[1,2-a]pyrazole-1,7-dione derivatives bearing vicinal aza-quaternary and tertiary carbon centers.

Organocatalytic dynamic kinetic resolution of azlactones to construct chiral N-acyl amino acid oxime esters.

A direct strategy to obtain N-acyl amino acid oxime esters has been developed through the dynamic kinetic resolution of azlactones with oximes. In the presence of a chiral bisguanidinium salt catalyst, a variety of chiral N-acyl amino acid oxime esters were generated in excellent enantiomeric excesses (up to 97%) and high yields (up to 99%). The active oxime esters could be used in dipeptide synthesis.