Controlled Synthesis and Uniform Anchoring of Hollow CuxO Nanocubes on Carbon Nanofiber for Enhanced Se(S)-Se(S) Bond Activation.

In the present study, we fabricated hollow cubic CuxO nanoparticles (∼23 nm) incorporated with CNF (HC-CuxO/CNF) through controlled thermal oxidation of solid cubic Cu2O nanoparticles (∼21 nm) supported on carbon nanofibers (SC-Cu2O/CNF) under airflow, exploiting the nanoscale Kirkendall effect. These hollow CuxO nanocubes with increased surface areas exhibited outstanding catalytic activity for unsymmetrical chalcogenide synthesis under ligand-free conditions.

A simple synthesis of surfactant-free polycrystalline CuO nanoparticles supported on carbon nanofibers for regioselective hydroboration of alkynes.

Copper oxide nanoparticles (CuO NPs) with a clean surface supported on carbon nanofibers (CNFs) in one-pot were prepared by simple solid-state grinding and aging followed by thermal treatment, yielding CuO nanoparticles with high (23.8 wt%) and uniform CuO loading in the absence of surfactants and solvent. The CuO NPs on CNFs (CuO/CNF) showed excellent catalytic activity in transforming a wide variety of alkynes into alkenyl boronates using B2Pin2 as a boron source in the absence of ligand and additives with high regioselectivity under mild conditions. Moreover, the present CuO/CNF catalyst was recyclable and possesses excellent chemoselectivity. The developed green synthetic approach is expected to offer exciting opportunities for designing monometallic or bimetallic nanoparticle catalysts on different supports applied in heterogeneous catalysis.

Statistical optimization of pullulan production from Asian palm kernel and evaluation of its properties.

Pullulan, a biodegradable exopolysaccharide, was produced from Asian Palmyra palm kernel by solid-state fermentation. Levels of medium variables, namely carbon to nitrogen ratio (C/N), pH, NaCl concentration and ZnSO4·5H2O concentration were optimized to maximize pullulan production using Box-Behnken design of experiments. Optimal values were predicted as: C/N ratio - 28.1, pH - 6.6, NaCl - 0.78 g/l and ZnSO4·5H2O - 0.37 g/l. Theoretical pullulan yield predicted under optimum condition was 30.4 mg/gds. Pullulan was produced under optimum condition and an experimental yield of 28.7 ± 0.3mg/gds was obtained. (13)C NMR spectra of the exopolysaccharide produced from Asian palm kernel revealed the presence of anomeric α (1→6) linked maltosyl units. The weight-average molecular weight of the polymer was determined to be 8.4×10(6)Da by gel permeation chromatography. Thermal decomposition temperature of pullulan was obtained to be 245°C. The tensile strength of pullulan film (0.5mm thick) was found to be 27 MPa.

CuO hollow nanosphere-catalyzed cross-coupling of aryl iodides with thiols.

New functionalized CuO hollow nanospheres on acetylene black (CuO/AB) and on charcoal (CuO/C) have been found to be effective catalysts for C-S bond formation under microwave irradiation. CuO catalysts showed high catalytic activity with a wide variety of substituents which include electron-rich and electron-poor aryl iodides with thiophenols by the addition of two equivalents of K2CO3 as base in the absence of ligands.

Augmentation of PCR efficiency using highly thermostable gold nanoparticles synthesized from a thermophilic bacterium, Geobacillus stearothermophilus.

Biogenic gold nanoparticles were synthesized from the Geobacillus stearothermophilus cell-free extract. These nanoparticles were characterized by UV-vis spectroscopy, FTIR, TEM, and XRD. The gold nanoparticles showed an absorption maximum at 522 nm. The TEM micrograph revealed the formation of monodispersed particles. The high degree of stability of the nanoparticle solution could be attributed to the secretion of certain capping proteins by the bacterium in the reaction mixture which was confirmed by the FTIR and UV-vis spectrometric analyses. The heat transfer property of the gold nanoparticles in aqueous solution has been explored in the current study for augmenting the PCR efficiency. The highly thermostable biogenic gold nanoparticles effectively increased the yield, product specificity besides reducing the reaction time of the PCR.