Citric acid-crosslinked ß-cyclodextrin supported zinc peroxide as a biocompatible H2O2 scavenger.

The aim of the present study was to evaluate the H2O2 scavenging activity of the ZnO2/ß-CD as a biocompatible composite. Zinc peroxide was prepared via sonochemical approach. To synthesize a green composite, ß-cyclodextrin was modified by citric acid (CA) and reacted with ZnO2 under ultrasonic irradiation. The prepared samples were characterized using XRD, SEM, TGA and FTIR analytical techniques. XRD analysis exhibited a typical pattern of ZnO2 and demonstrated the presence of citric acid and ß-cyclodextrin in composite. The results of the catalytic assay showed that the ZnO2/CA-ßCD composite displayed stronger capability to decompose H2O2 in comparison to ZnO2 particles (about seven times). It was attributed to increased adsorption capacity and solubility of composite due to the presence of citric acid and ß-cyclodextrin. MTT assay studies confirmed the non-cytotoxic nature of ZnO2 particles and ZnO2/CA-ßCD composite.

Magnetic chitosan nanocomposite: As a novel catalyst for the synthesis of new derivatives of N-sulfonylamidine and N-sulfonylimidate.

This study reports the synthesis and characterization of a highly active catalyst based on chelated copper iodide on magnetic chitosan-salicylaldehyde Schiff base. This catalyst was successfully used for the three-component reaction of N-propargylphthalimide, tosylazide, and NH or OH containing nucleophiles to access new classes of N-sulfonylamidine or N-sulfonylimidate derivatives. The products, which were constructed via an in situ generated sulfonyl keteneimine intermediate, were obtained in good to excellent yields. Short reaction times, easy separation and reusability without significant loss of catalyst activity were found to be the notable features of this synthetic protocol.

Highly efficient isobutyraldehyde-mediated epoxidation of cyclic alkenes with dioxygen catalyzed by a novel dimeric manganese(II) complex containing an easy-to-prepare flexible carboxamide ligand.

Dioxygen epoxidation of cyclic alkenes into their corresponding epoxides was successfully achieved in good yield by using a novel binuclear manganese carboxamide complex as the catalyst and isobutyraldehyde as the cosubstrate.

Immobilization of iron tetrasulfophthalocyanine on functionalized MCM-48 and MCM-41 mesoporous silicas: catalysts for oxidation of styrene.

Iron tetrasulfophthalocyanine (FePcS) has been anchored on the surface of functionalized MCM-48 and MCM-41 silicas by means of chemical bonding to aminosilane groups. The prepared materials, FePcS/NH2-MCM-48 and FePcS/NH2-MCM-41, were characterized by diffuse reflectance UV-vis and infrared (IR) spectroscopies, low-angle X-ray diffraction (XRD), and surface area analysis (BET). The tendencies of FePcS absorption on functionalized MCM-48 and MCM-41 were measured by UV-vis spectroscopy. The functionalized MCM-48 showed a larger amine to silica ratio than the functionalized MCM-41. Low-angle X-ray diffraction analysis showed that, by anchoring iron tetrasulfophthalocyanine into functionalized MCM-48 and MCM-41, the intensity of main reflection decreased. The catalytic activities of the supported iron tetrasulfophthalocyanine were examined by the oxidation of styrene in the presence of tert-butyl hydroperoxide. The FePcS/NH2-MCM-48 showed higher activity and durability in the liquid-phase oxidation of styrene under mild condition compared with the FePcS/NH2-MCM-41 and unsupported catalyst.