Graphene oxide was found to be a highly efficient, reusable and cost-effective organocatalyst for the aza-Michael addition of amines to activated alkenes to furnish corresponding β-amino compounds in excellent yields.

No abstract

New graphene oxide (GO)-tethered-Co(II) phthalocyanine complex [CoPc-GO] was synthesized by a stepwise procedure and demonstrated to be an efficient, cost-effective and recyclable photocatalyst for the reduction of carbon dioxide to produce methanol as the main product. The developed GO-immobilized CoPc was characterized by X-ray diffraction (XRD), FTIR, XPS, Raman, diffusion reflection UV/Vis spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP-AES), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). FTIR, XPS, Raman, UV/Vis and ICP-AES along with elemental analysis data showed that Co(II) -Pc complex was successfully grafted on GO. The prepared catalyst was used for the photocatalytic reduction of carbon dioxide by using water as a solvent and triethylamine as the sacrificial donor. Methanol was obtained as the major reaction product along with the formation of minor amount of CO (0.82 %). It was found that GO-grafted CoPc exhibited higher photocatalytic activity than homogeneous CoPc, as well as GO, and showed good recoverability without significant leaching during the reaction. Quantitative determination of methanol was done by GC flame-ionization detector (FID), and verification of product was done by NMR spectroscopy. The yield of methanol after 48 h of reaction by using GO-CoPc catalyst in the presence of sacrificial donor triethylamine was found to be 3781.8881 μmol g(-1)  cat., and the conversion rate was found to be 78.7893 μmol g(-1) cat. h(-1). After the photoreduction experiment, the catalyst was easily recovered by filtration and reused for the subsequent recycling experiment without significant change in the catalytic efficiency.

The first report on the use of vanadium-based catalysts for oxidative cyanation of tertiary amines with molecular oxygen in the presence of sodium cyanide and acetic acid to afford the corresponding alpha-aminonitriles in good to excellent yields is described.

A ruthenium trinuclear polyazine complex was synthesized and subsequently immobilized through complexation to a graphene oxide support containing phenanthroline ligands (GO-phen). The developed photocatalyst was used for the photocatalytic reduction of CO 2 to methanol, using a 20 watt white cold LED flood light, in a dimethyl formamide-water mixture containing triethylamine as a reductive quencher. After 48 h illumination, the yield of methanol was found to be 3977.57 AE 5.60 mmol g cat À1.The developed photocatalyst exhibited a higher photocatalytic activity than graphene oxide, which provided a yield of 2201.40 AE 8.76 mmol g cat À1. After the reaction, the catalyst was easily recovered and reused for four subsequent runs without a significant loss of catalytic activity and no leaching of the metal/ligand was detected during the reaction.

No abstract

A variety of tertiary nitrogen compounds have been efficiently oxidized to their corresponding N-oxides in excellent yields with molecular oxygen as a sole oxidant and ruthenium trichloride as catalyst.

The first report on heterogeneously catalyzed oxidative cyanation of various tertiary amines to the corresponding a-amino nitriles with high yields and selectivity by using hydrogen peroxide oxidant in presence of sodium cyanide and Fe(II) phthalocyanine supported on a polymer as catalyst is described. The present method has the added benefits of facile recovery of the catalyst from the reaction mixture and its subsequent use without further activation. Consistent catalytic activity with no metal leaching was observed during this course.