Maryam Mirza-Aghayan

New ZnO nanostructures as non-enzymatic glucose biosensors.

In a new approach, shape controlled synthesis of zinc oxide nanostructures were carried out using a solvothermal route assisted amino acids such as L-Lysine (lysine), L-Cysteine (cysteine) and L-Arginine (arginine) as bifunctional species with (or without) urea or oxalic acid as additives which affect the pH of the reaction. Rod, powder, particle, cube, rock candy-like, sheet, sphere, brain-like, groundnut-like and pussy willow-like morphologies were obtained through the synthetic route. Particle sizes varied from 25 nm to4 μm. To test the application, nine ZnO nanostructures, formulated by multi-walled carbon nanotube (MWCNT) on glassy carbon electrode (GCE) were applied as new nanobiosensors for detecting glucose in a simple and inexpensive way without using any glucose oxidase or nafion. Glucose sensing accomplished in a phosphate buffer solution (PBS, pH=7) for ZnO/MWCNT/GCE samples. Results showed that in this non-enzymatic biosensor system, spherical ZnO obtained from zinc acetate/cycteine/oxalic acid synthetic route has the highest sensitivity of 64.29 μA/cm(2) mM with repeatable results. For the mentioned sensor, no interference observed in the presence of dopamine, uric acid and fructose.

Microwave‐Assisted Efficient Synthesis of Dihydropyrimidines in Solvent‐Free Condition

Abstract An efficient synthesis of 3,4‐dihydropyrimidinones from an aldehyde, a ketoester, and a urea or thiourea using a catalytic amount of ferric chloride hexahydrate is described. Microwave irradiation has been used to accelerate the synthesis of the Biginelli compounds under solvent‐free conditions and in a short reaction time and with good yield.

A novel and efficient method for double bond isomerization

Isomerization of α-alkenes is carried out in the presence of a catalytic amount of palladium (II) chloride and triethylsilane at room temperature. This novel and efficient method affords high yields in the absence of solvent for double bond isomerization of alkenes.

Sulfonated reduced graphene oxide as a highly efficient catalyst for direct amidation of carboxylic acids with amines using ultrasonic irradiation.

Sulfonated reduced graphene oxide nanosheets (rGO-SO3H) were prepared by grafting sulfonic acid-containing aryl radicals onto chemically reduced graphene oxide (rGO) under sonochemical conditions. rGO-SO3H catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). rGO-SO3H catalyst was successfully applied as a reusable solid acid catalyst for the direct amidation of carboxylic acids with amines into the corresponding amides under ultrasonic irradiation. The direct sonochemical amidation of carboxylic acid takes place under mild conditions affording in good to high yields (56-95%) the corresponding amides in short reaction times.

Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone

A sonochemical procedure for direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone in an alcoholic solvent is described. Mild reaction conditions, short reaction times, cost-effectiveness, and facile isolation of the products make the present system as a practical method.

Convenient and Efficient One-Pot Method for the Synthesis of 2-Amino-tetrahydro-4H-chromenes and 2-Amino-4H-benzo[h]-chromenes Using Catalytic Amount of Amino-Functionalized MCM-41 in Aqueous Media

Abstract A convenient and efficient one-pot method for the synthesis of 2-amino-tetrahydro-4H-chromene and 2-amino-4H-benzo[h]-chromene derivatives has been developed using a catalytic amount of amino-functionalized MCM-41 in aqueous medium. This efficient technique has the advantages of giving 4H-tetrahydro-chromene and 4H-benzo[h]chromene building blocks using a reusable catalyst in good to excellent yields, to be completed in short reaction times with a simple product isolation procedure. GRAPHICAL ABSTRACT

Zirconocyclisation: Access to new racemic (di) phosphines☆

Abstract The bis-allylic 1 and the bis-propargylic 6 derivatives react with the zirconocene “ZrCp2” and lead, after electrophilic addition, to the corresponding chiral trans heterocyclopentanes (MSi,Ge,P) 3–5 and bis-methylenecyclopentanes 8. New chiral diphosphine 9 is obtained starting from the intermediate complex 2 or the functionalized heterocyclopentane 4.

Ultrasound irradiation effects on the asymmetric michael reaction

Abstract Ultrasound irradiation enhances the rate and improves the yield of the heterogeneous asymmetric Michael reaction without any modification of the enantioselectivity with respect to standard procedure. These improvements are assigned to ultrasonic mechanical effects.

Multivalent calix[4]arene-based fluorescent sensor for detecting silver ions in aqueous media and physiological environment.

A new derivative of dipodal 1,3-calix[4]arene-based chemosensor (R), which was containing several binding sites have been synthesized and characterized by NMR, IR and LC-MS spectroscopic methods. The selectivity of Rhas been investigated in aqueous methanol, resulting in fluorescence shift and selective recognition of Ag+ among 20 various alkali, alkaline earth and transition metal ions. Microstructural features of R and its complex with Ag+have been investigated by Atomic Force Microscopy (AFM). AFM images can clearly differentiate R from its complex of Ag+. Moreover; the complicated binding mode of metal-ligand complex has been explored by UV-Vis, LC-MS, FIR, Fluorescence titration, Jobs plot method and theoretical approaches. Density functional theory (DFT) method at B3LYP/LANL2DZ level of theory was employed for computational studies. Theoretical calculations revealed that selectivity and specificity of R toward Ag+ could be attributed to structural conformation of 1,3-alternate-calix[4]arene scaffold and molecular electrostatic potential of its surface. Furthermore; the competitive experiments were carried out to test sensors ability for practical uses. Finally, the efficiency of R in matrix of physiological cations was examined and showed gradual emission enhancement which makes R an ideal candidate for monitoring of Ag+ in physiological environment.

A NOVEL AND EFFICIENT ONE-POT METHOD TO BIGINELLI-LIKE SCAFFOLDS

A novel and efficient one-pot method for the preparation of fused ring 3,4-dihydropyrimidin-2(1H)-ones and thiones from cyclocondensation of aldehydes, cyclic ketones and urea or thiourea using a catalytic amount of cupric chloride under mild conditions reaction is described. This new method has the advantage to give high yields, to be completed in short reaction times and simple product isolation procedure.