Ali Akbari

Vanadium (V) and Tungsten (VI) Oxoperoxo-Complexes Anchored on Fe 3 O 4 Magnetic Nanoparticles: Versatile and Efficient Catalysts for the Oxidation of Alcohols and Sulfides

Vanadium (V) and tungsten (VI) oxoperoxo complexes supported on Fe3O4 magnetic nanoparticles were synthesized and characterized. These compounds are assigned as catalyst 1 (C1: Fe3O4@Gly@r-Py@VO3) and catalyst 2 (C2: Fe3O4@Gly@r-Py@WO3), respectively, and were found to be efficient and reusable heterogeneous catalysts for the oxidation of alcohols and sulfides using H2O2.Graphical Abstract

Encapsulation of Satureja hortensis L. (Lamiaceae) in chitosan/TPP nanoparticles with enhanced acaricide activity against Tetranychus urticae Koch (Acari: Tetranychidae)

The objective of this study was the fabrication of encapsulated Satureja hortensis essential oil (S.EO) in chitosan/tripolyphosphate nanoparticles (CS/TPP-NPs) via ionic gelation technique and investigation of its acaricidal effect. A high encapsulation efficiency of 96.17% was obtained, which shows successful encapsulation of EOs in CS-TPP nanoparticles. Transmission electron microscopy (TEM) analysis proved the formation of spherical S. hortensis EO-loaded chitosan nanoparticles (S.EO@NPs). Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated the presence of encapsulated S.EO in CS/TPP nanoparticles. The average size of nanoparticles was found to be 192.1 ± 11 nm using dynamic light scattering (DLS) technique. Moreover, durability and fumigant acaricide activity of S.EO@NPs against Tetranychus urticae Koch were investigated. The obtained results demonstrated that there were considerable differences between pure S. hortensis EO and S.EO@NPs in their ovicidal, adulticidal, and persistence activities against T. urticae. The LC50 values of pure EO and as-prepared S.EO@NPs against adult mite were 4.95, 46.98 µL/L after 24 h exposure and 2.02, 31.30 µL/L after 72 h exposure, respectively. Fumigation exposure for 24 and 72 h showed that the sensitivity of adults T. urticae were more than the eggs of T. urticae. The LC50 values of fumigant toxicity of pure S.EO and S.EO@NPs against eggs of T. urticae were measured after 24 and 72 h. The experimental results for 24 h treatment showed 6.71 and 211.66 µL/L air LC50 values for pure S.EO and S.EO@NPs, respectively. In the case of 72 h exposure, The LC50 values of pure S.EO and S.EO@NPs were 4.15 and 107.38 µL/L air, respectively. A sustained release of S.EO from S.EO@NPs was observed during 25 days of the study, indicating the persistence acaricide activity for a long time. The as-prepared S.EO@NPs and pure S.EO illustrated 67% and 2% mortality at 18th day exposure, respectively. The notable increasing of the residual fumigant toxicity may be related to the slow and sustainable release of the active ingredient of EO. Based on this study, the S.EO@NPs showed significantly residual adulticidal activity against adults of T. urticae. S.EO@NPs would be recommended as an alternative for pure EOs and other common acaricides.

CdSe Quantum Dots Based Nano-Biosensor for Detection of 185delAG Mutation in BRCA1 Gene, Responsible for Breast Cancer

A new method based on CdSe quantum dots (QDs) was developed to detect 185delAG mutation in BRCA1 gene. In this method P2-NH2 strand was covalently attached to QDs possessing carboxylic acid to provide QD-P2, and its emission was studied against other probs. In the presence of cDNA and P1-NH2, emission of QD-P2 was 85% more intense than just pure bare QD-P2. Moreover, new peak appeared in emission spectrum in higher wavelength which could be associated with formation of more organized shrinked aggregates due to connection between QDs by DNA strands. Partial (35%) increase in the intensity of emission in the presence of mDNA was observed, according to the formation of disorganized aggregates and therefore less rigid system, which is attributed to mutation in DNA strands. The generation of organized small and disorganized aggregates in the presence of cDNA and mDNA, respectively, was approved by DLS analysis and zeta potential measurements.

Highly chemoselective Baylis-Hillman and aldol reactions of 2H-thiopyran-4(3H)-one using tertiary amine catalysts in aqueous media.

For the first time, the Baylis-Hillman (BH) reaction of 2H-thiopyran-4(3H)-one is investigated, and surprisingly, the reaction of 2H-thiopyran-4(3H)-one with aldehydes in the presence of different tertiary amines shows excellent chemo- and regioselectivity in water. At room temperature, DBU affords BH adducts, but with DABCO, aldol products were obtained. In the case of DABCO, Et(3)N, or DMAP, domino aldol-rearrangement reactions occurred at 45-50 °C.

8-Hydroxyquinoline Functionalized Graphene Oxide: an Efficient Fluorescent Nanosensor for Zn2+ in Aqueous Media

A nanosensor, based on 8-hydroxyquinoline functionalized graphene oxide, was developed for the fluorescence detection of Zn2+. It showed high selectivity and sensitivity for Zn2+ion in aqueous solution over other metal ions such as Li+, Na+, Ca2+, Mg2+, Al3+, Cd2+, Co2+, Cu2+, Hg2+, Ni2+, Pb2+, Fe2+, Fe3+and Cr3+. Due to the linearity of the emission intensity toward Zn2+ concentration, fluorescent technique could be used for the detection of Zn2+ ion even at very low concentrations.

Synthesis, crystal structure and catalytic activity of an oxo-diperoxo tungsten(VI) complex containing an oxazine ligand for selective oxidation of sulfides

Abstract A novel oxo-diperoxo tungsten(VI) complex, [WO(O2)2(Hphox)], was prepared by reaction of WO3 in H2O2 with an oxazine-type ligand, 2-(2′-hydroxylphenyl)oxazine (Hphox). The complex was characterized by FTIR, 1H NMR and elemental analysis. The single-crystal X-ray diffraction studies revealed a seven-coordinate tungsten center with a distorted octahedral geometry. The [WO(O2)2(Hphox)] complex was applied as a catalyst in efficient and selective oxidation of sulfide to sulfoxide using 30% H2O2 or UHP (urea hydrogen peroxide) as oxidants. This catalyst showed excellent catalytic activities and high selectivities in producing a variety of aryl and alkyl sulfoxides under mild conditions. To get an insight into the mechanisms of oxidation of sulfides, the mechanistic studies were monitored by UV–Vis spectroscopy. Graphical Abstract