Fabrication of amino-functionalized Fe_3O_4@Cu_3(BTC)_2 for heterogeneous Knoevenagel condensation

Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3（BTC）2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.

Fe_3O_4@UiO-66-NH_2 core–shell nanohybrid as stable heterogeneous catalyst for Knoevenagel condensation

separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed by dispersing magnets in a dimethylformamide （DMF） solution con- taining two metal-organic framework （MOF） precursors, namely ZrCI4 and 2-aminobenzenetricar- boxylic acid. This method is simpler and more efficient than previously reported step-by-step method in which magnets were consecutively dispersed in DMF solutions each containing one MOF precursor, and the obtained Fe304@UiO-66-NH2 with three assembly cycles has a higher degree of crystallinity and porosiW. The core-shell Fe3O4@UiO-66-NH2 is highly active and selective in Knoevenagel condensations because of the bifunctionality of UiO-66-NH2 and better mass transfer in the nano-sized shells. It also has good recycling stability, and can be recovered magnetically and reused at least four times without significant loss of catalytic activity and framework integrity. The effects of substitution on the reactivity of benzaldehyde and of substrate size were also investigated.

Study on Removal of Bilirubin with Magnetic Affinity Separation Technique

An affinity adsorbent, Cibacron Blue 3GA immobilized magnetic polyvinyl alcohol (PVA) microspheres was used for bilirubin removal taking the advantage of easy separation of magnetic sorbent from the biosystem. Fe3O4 superparamagnetic particles was synthesized with hydrothermal reaction of ferrous chloride (FeCl2) and ferric chloride (FeCl3). Such magnetic particles are then encapsulated in biocompatible PVA to form magnetic polymer microspheres sized from 2 to 15 nm with hydroxyl groups on its surface. Cibacron Blue 3GA, a dye-ligand, was covalently coupled with the polyvinyl alcohol through the nucleophilic reaction between the chloride of its triazine ring and the hydroxyl groups of PVA molecules under alkaline condition. The affinity adsorbent carried 21.1μmol Cibacron Blue 3GA per gram magnetic polymer microspheres was used to remove unconjugated and conjugated bilirubin from the solution which was composed of bilirubin or bilirubin and protein. After the adsorption, the adsorbent loaded with bilirubin was removed easily in the magnetic field.

Bio-inspired enantioseparation for chiral compounds

Biomacromolecules including protein and nucleic acids are considered as promising chiral selectors in the fields of enantioselective separation, owing to their inherent chirality, polymorphous structures, stable physicochemical properties, good biocompatibility as well as susceptible modification and regulation. In this review, firstly,enantioselective recognition mechanism of proteins and nucleic acids toward different enantiomers is discussed,as well as their potential applications on the chiral separation of racemic compounds. Secondly, preparative enantioseparation adopting biomolecule-modified hybrid materials including porous microspheres, magnetic nanoparticles and affinity membranes, are introduced respectively. Finally, novel chiroptical materials constructed on the basis of chiral induction, transfer, amplification and transcription, are recognized as promising candidates in future applications.