A Novel Strategy for Determination of Paracetamol in the Presence of Morphine Using a Carbon Paste Electrode Modified with CdO Nanoparticles and Ionic Liquids

A voltammetric sensor for determination of paracetamol in the presence of morphine is described for the first time. The synthesized CdO nanoparticles were characterized with different methods such as scanning electron microscopy (SEM) and X‐ray diffraction (XRD). The paracetamol and morphine peaks are separated ca. 0.37 and 0.65 V, respectively; hence paracetamol can be analysed in the presence of morphine and more than 21 times of the current excess of paracetamol. The detection limits for paracetamol and morphine were 0.07 and 0.1 μM, respectively. The sensor has been successfully applied for the assay of the above compounds in real samples.     

Nanosized cationic and anionic manganese porphyrins as mesoporous catalysts for the oxidation of olefins: Nano versus bulk aggregates

In this study, catalytic activity of bulk and nano‐sized meso‐tetrakis(4‐sulfonatophenyl)porphyrinatomanganese(III) acetate, MnTPPS₄(OAc), (ammonium salt) and meso‐tetrakis(3‐methylpyridyl)porphyrinatomanganese(III) acetate, MnT(3‐MePy)P(OAc) (tosylate salt) for the oxidation of olefins with tetra‐n‐butylammonium Oxone has been studied and compared with that of the bulk counterparts. The nanoparticles were prepared by mixing solvent techniques using water, (triethyleneglycol) monomethyl ether and dimethylsulfoxide or acetonitrile. The formation of nano‐sized catalysts was confirmed by UV‐Vis spectroscopy, DLS and AFM. Nitrogen porosimetry measurements indicated the homogeneous pore size distribution in the bulk and nano‐sized manganese porphyrins. In spite of the high oxidizability of Oxone, the heterogenized manganese porphyrins showed a significantly higher oxidative stability relative to their homogeneous counterparts within a reaction time of 6 h. The increase in the catalytic activity induced by the formation of nano‐sized catalysts was more pronounced in the case of MnT(3‐MePy)P(OAc). MnT(3‐MePy)P(OAc) may be recovered and reused for at least 4 times without any significant decrease in the catalyst efficiency. In the case of MnTPPS₄(OAc) a large decrease in the catalytic activity was observed after the first use of the catalyst. The latter was attributed to higher degrees of catalyst degradation in the case of MnTPPS₄(OAc).     

Temperature dependent electrical conductivity of polyaniline/Y2O3 composites

Composites of polyaniline with yttrium oxide (Y₂O₃) nanoparticles have been prepared by chemical polymerizations method by increasing the weight percentage of yttrium oxide. X-Ray diffraction (XRD) and Fourier Transform Infrared Spectra (FTIR) were used to characterize the composites. XRD and FTIR pattern indicate that Polyaniline (PANI) is intercalated into the layers of Y₂O₃ nanoparticles successfully by in situ polymerization and therefore the degree of crystallinity increases due to crystalline of yttrium oxide nanoparticles. The scanning electron micrographs (SEM) also confirm the formation of dual phase of platelet as well as of flaky structure in PANI-Y₂O₃. Temperature dependant DC conductivity showed three dimensional variable ranges hopping (3D VRH) model. Activation energy, density of states and hopping length are calculated and found to be influenced by intercalating PANI into the layers of Y₂O₃ clay.     

Solvent effects on catalytic activity of manganese porphyrins with cationic,anionic and uncharged meso substituents: Indirect evidence on the nature of active oxidant species

Oxidation of cyclohexene and styrene with sodium periodate and tetra‐n‐butylammonium periodate (TBAP) catalyzed by MnT(3‐MePy)P(OAc), MnT(4‐SO₃)PP(OAc) and MnTPP(OAc) has been studied in water, methanol, acetonitrile and dichloromethane as solvents. The results show significant dependence of the product distribution on the type of solvent and the electronic nature of the aryl substituents introduced at the porphyrin periphery. While the oxidation of cyclohexene and styrene in the presence of MnT(3‐MePy)P(OAc) and MnTPP(OAc) in water (also in methanol) gave the corresponding epoxides as nearly the sole product, performing the reactions in the presence of MnT(4‐SO₃)PP(OAc) yielded the products of allylic oxidation, cyclohexene‐2‐ol and cyclohexene‐2‐one and acetophenone as the major products. In the case of styrene, performing the reaction in the presence of MnT(4‐SO₃)PP(OAc), MnT(3‐MePy)P(OAc) and MnTPP(OAc) in acetonitrile gave a mixture of styrene oxide and acetophenone as the products. Under the same conditions, the oxidation of cyclohexene afforded cyclohexene oxide as approximately the exclusive product. Furthermore, the oxidation of olefins in dichloromethane gave the corresponding epoxide as the exclusive products. The product distributions observed in the protic and aprotic solvents were used to provide indirect evidence on the relative contribution and reactivity of high valent manganese oxo and periodato Mn(III) porphyrin species to the oxidation reactions.     

Mo (CO)6‐assisted Pd‐supported magnetic graphene oxide‐catalyzed carbonylation‐cyclization as an efficient way for the synthesis of 4(3H)‐quinazolinones

In this paper, a novel catalyst is introduced based on the immobilization of palladium on modified magnetic graphene oxide nanoparticles. The catalyst is characterized by several methods, including transmission electron microscopy, scanning electron microscopy, X‐ray fluorescence, vibrating‐sample magnetometer, Fourier transform‐infrared and dynamic light scattering (DLS) analysis. The activity of the catalyst was investigated in the synthesis of 4(3H)‐quinazolinones via Pd‐catalyzed carbonylation‐cyclization of N‐(2‐bromoaryl) benzimidamides by Mo (CO)₆. The Mo (CO)₆ is used as a carbon monoxide source for performing the reaction under mild conditions. The catalyst showed good reusability, and no change in activity was observed after 10 cycles of recovery.     

One-bond 1J(15N,H) coupling constants at sp2-hybridized nitrogen of Schiff bases,enaminones and similar compounds: A theoretical study

¹J(¹⁵N,H) coupling constants for enaminones and NH-forms of intramolecularly hydrogen-bonded Schiff bases as model compounds for sp²-hybridized nitrogen atoms are evaluated using density functional theory (DFT) to find the optimal functionals and basis sets. Ammonia is used as a test molecule and its one-bond coupling constant is compared with experiment. A methylamine Schiff base of a truncated molecule of gossypol is used for checking the performance of selected B3LYP, O3LYP, PBE, BHandH, and APFD density functionals and standard, modified, and dedicated basis sets for coupling constants. Both in vacuum and in chloroform, modeled by the simple continuum model of solvent, the modified basis sets predict significantly better the ¹J(¹⁵N,H) value in ammonia and in the methylamine Schiff base of a truncated molecule of gossypol than the standard basis sets. This procure is then used on a broad set of intramolecularly hydrogen-bonded molecules, and a good correlation between calculated and experimental one-bond NH coupling constants is obtained. The ¹J(¹⁵N,H) couplings are slightly overestimated. The calculated data show for hydrogen-bonded NH interatomic distances that the calculated values depend on the NH bond lengths. The shorter the bond lengths, the larger the ¹J(¹⁵N,H). A useful correlation between ¹J(¹⁵N,H) and NH bond length is derived that enables realistic predictions of one-bond NH coupling constants. The calculations reproduce experimentally observed trends for the studied molecules.     

Zn and Zr co-doped M-type strontium hexaferrite: Synthesis,characterization and hyperthermia application

In the present study, hard ferromagnetic (M-type strontium hexaferrite) SrFe₁₂O₁₉ was co-doped by Zn and Zr for magnetic hyperthermia applications. As a result of the high concentration of single domain SrFe₁₂O₁₉ nanoparticles (suspended in the ferrofluid), they found a large hydrodynamic diameter, which caused a long-time Brownian relaxation under the AC magnetic field. On the other hand, increasing the Zn-Zr content (low concentration of SrFe₁₂O₁₉) led to a drop in anisotropy, which coincided with a short-time N´eel relaxation. All of the substituted samples with a multi-disperse state in ferrofluid exhibited an almost equal amount of the N´eel and Brownian effects. Consequently, the magnetic saturation (M_s) was considered as the dominant factor in the specific absorption rate (SAR) of the substituted samples. Transformation to the mono-disperse state was followed by the decrease of the Brownian relaxation time and hence the increase of the SAR. The interesting point in mono-disperse state was the heat generation of pure SrFe₁₂O₁₉ under the AC magnetic field as a result of the decrement of the Brownian relaxation time.