Alpesh K. Sharma

Graphene oxide grafted with Pd17Se15 nano-particles generated from a single source precursor as a recyclable and efficient catalyst for C–O coupling in O-arylation at room temperature

The Pd17Se15 nanoparticles, synthesized for the first time from a single source precursor [Pd(L)Cl2] {L = 1,3-bis(phenylselenyl)propan-2-ol} and grafted onto graphene oxide, show high catalytic activity in C-O coupling between aryl/heteroaryl chlorides/bromides and phenol at room temperature (Pd loading 1 mol%; yield up to 94%).

Single source precursor routes for synthesis of PdTe nanorods and particles: solvent dependent control of shapes

The PdTe NPs (hexagonal) and nanorods (first example) have been synthesized for the first time from single source precursors (SSPs), [Pd(L1)Cl2] (1) and [Pd(L2)Cl]BF4 (2) [L1, 4-bromo-1-[2-(4-methoxyphenyltellanyl)ethyl]-1H-pyrazole; L2, bis-[2-(4-bromopyrazol-1-yl)ethyl]telluride], by their thermolysis in an OA–ODE mixture (1:1) and TOP respectively. The composition of the PdTe phase does not change with SSP/solvent. Complex 2 gives small size nanostructures.

Reusable Catalyst for Transfer Hydrogenation of Aldehydes and Ketones Designed by Anchoring Palladium as Nanoparticles on Graphene Oxide Functionalized with Selenated Amine

The treatment of graphene oxide with ClCH2COOH, thionyl chloride, and 2-(phenylselenyl)ethylamine successively has resulted in functionalization of its surface with selenated ethylamine molecules which may act as chelating (Se, N) ligands. The graphene oxide grafted with (Se, N) donor sites (GO-Se) on treatment with Na2PdCl4 and NaOH gave GO-Se anchored with Pd(0) nanoparticles (NPs) (GO-Se-Pd). The X-ray diffraction (powder), FT-IR, XPS, Raman spectroscopy, thermogravimetric analysis (TGA), and electron microscopic techniques (SEM and HR-TEM) authenticated the formation of GO-Se-Pd. The distribution of Pd(0) NPs of size ∼1-3 nm on GO-Se was found nearly uniform. The transfer hydrogenation of carbonyl compounds (aldehydes/ketones) with 2-propanol was catalyzed with GO-Se-Pd. The catalyst equivalent to 0.25 mol % of Pd was sufficient to convert aldehydes and ketones to alcohols in good yield (nearly quantitative for some substrates) and found somewhat more efficient for aldehydes than ketones. The reusability of GO-Se-Pd studied for transfer hydrogenation of 4-anisaldehyde to the corresponding alcohol can be understood by ∼96% conversion even in the sixth catalytic run. Flame AAS analysis of GO-Se-Pd revealed negligible leaching of Pd even after the sixth catalytic reaction cycle. Hot filtration experiments suggested the heterogeneous nature of the catalyst.