Chemistry - Research Publications

Permanent URI for this collectionhttps://kr.cup.edu.in/handle/32116/37

Browse

Author: search.filters.author.Bose, Shubhankar Kumar

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Ag-S Type Quantum Dots versus Superatom Nanocatalyst: A Single Sulfur Atom Modulated Decarboxylative Radical Cascade Reaction
    (American Chemical Society, 2023-04-06T00:00:00) Meena, Sangeeta; Dastider, Saptarshi G.; Nishad, Chandra Shekhar; Jangid, Dilip Kumar; Kumar, Pankaj; Khirid, Samreet; Bose, Shubhankar Kumar; Mondal, Krishnakanta; Banerjee, Biplab; Dhayal, Rajendra S.
    The preparation of high-nuclearity silver nanoclusters in quantitative yield remains exclusive and their potential applications in the catalysis of organic reactions are still undeveloped. Here, we have synthesized a quantum dot (QD)-based catalyst, [Ag62S13(SBut)32](PF6)4 (denoted as Ag62S12-S) in excellent yield that enables the direct synthesis of pharmaceutically precious 3,4-dihydroquinolinone in 92% via a decarboxylative radical cascade reaction of cinnamamide with ?-oxocarboxylic acid under mild reaction conditions. In comparison, a superatom [Ag62S12(SBut)32](PF6)2 (denoted as Ag62S12) with identical surface anatomy and size, but without a central S2- atom in the core, gives an improved yield (95%) in a short time and exhibits higher reactivity. Multiple characterization techniques (single-crystal X-ray diffraction, nuclear magnetic resonance (1H and 31P), electrospray ionization mass spectrometry, energy dispersive X-ray spectroscopy, Brunauer-Emmett-Teller (BET), Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis) confirm the formation of Ag62S12-S. The BET results expose the total active surface area in supporting a single e- transfer reaction mechanism. Density functional theory reveals that leaving the central S atom of Ag62S12-S leads to higher charge transfer from Ag62S12 to the reactant, accelerates the decarboxylation process, and correlates the catalytic properties with the structure of the nanocatalyst. � 2023 American Chemical Society.
  • No Thumbnail Available
    Item
    Facile synthesis of alkyl- and arylboronate esters enabled by a carbon nanotube supported copper catalyst
    (Royal Society of Chemistry, 2022-11-15T00:00:00) Saini, Suresh; Gavali, Deepak S.; Bhawar, Ramesh; Thapa, Ranjit; Dhayal, Rajendra S.; Bose, Shubhankar Kumar
    An efficient synthesis of alkylboronate esters via alkyl halide borylation catalysed by copper nanoparticles stabilised on nitrogen-doped carbon nanotubes (N-CNT) is reported. This nanocatalyst provides practical access to alkylboronate esters at room temperature in 1 h, with good functional group tolerance. The procedure is also applicable to the borylation of benzyl chlorides and bromides. Radical clock experiments suggest that the reaction involves a radical pathway. The catalyst can be recycled up to ten runs without appreciable loss in the activity. In addition, we demonstrated the use of this supported copper catalyst for the anti-Markovnikov-selective hydroboration of vinylarenes and borylation of aryl halides with B2pin2, providing alkyl- and arylboronate esters, respectively, in good to excellent yields. � 2023 The Royal Society of Chemistry.