Browsing by Author "Giri, Kousik"

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    Disruptive influence of the host cage C60 on the guest He�H+ bond and bonding in H3+
    (Elsevier B.V., 2021-07-13T00:00:00) Giri, Kousik; Mishra, Brijesh K.; Sathyamurthy, Narayanasami
    Although a helium atom prefers to stay at the centre of a fullerene (C60) cage and a proton binds with one of the carbon atoms from inside, DFT(MN15)/cc-pVTZ and DLPNO-MP2/def2-TZVP calculations show that the helium atom and the proton in HeH+ prefer to stay away from the centre of the cage, weakening the He�H+ covalent bond considerably. Both the helium atom and the proton exhibit noncovalent interactions with the carbon atoms of two pentagons at the opposite ends of the fullerene cage. Our calculations also show that a linear arrangement of H3+ (inside C60), pointing towards the centres of two pentagons opposite to each other, with the proton breaking away from H2, is energetically more favored over the equilateral triangle geometry of free H3+. � 2021 Indian Chemical Society
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    Pd/C-Catalyzed Carbonylative Amidation for the Synthesis of 2-Carboxamidocyclohexane-1,3-diones
    (American Chemical Society, 2023-10-05T00:00:00) Sheetal, None; Chauhan, Arvind Singh; Sharma, Ajay Kumar; Sharma, Navneet; Giri, Kousik; Das, Pralay
    Herein, a first-ever heterogeneous Pd/C-catalyzed single-step tandem approach for the synthesis of 2-carboxamidocyclohexane-1,3-diones via direct carbonylative C-H amidation of cyclohexane-1,3-diones is reported. The reaction progressed under base-, oxidant-, and ligand-free conditions employing oxalic acid as a CO surrogate and sodium azide as a nitrogen precursor in a double-layer vial system. � 2023 American Chemical Society.
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    Supported-Pd catalyzed tandem approach for N-arylbenzamides synthesis
    (Elsevier B.V., 2021-11-21T00:00:00) Sheetal; Sharma, Ajay Kumar; Shaifali; Bhattacherjee, Dhananjay; Sharma, Navneet; Giri, Kousik; Das, Pralay
    Aryl iodides as dual arylating agent for C-terminal from oxalic acid [(CO2H)2] and N-terminal from sodium azide (NaN3) for N-aryl benzamides (Ar-CO-NH-Ar) synthesis is a rare invention which has been attempted successfully under this study. A single step tandem approach for the synthesis of N-aryl benzamides has been developed through bifunctional transformation of aryl iodides with in-situ CO from (CO2H)2 and NaN3 following two different pathways of carbonylation and azidation. The polystyrene supported palladium (Pd@PS) catalyst was found to be well compatible to perform the domino-reaction in a double layer vial (DLV) system under base, ligand and additive-free conditions. Moreover, the same approach was further extended with aryl azides for unsymmetric N-aryl benzamides (Ar-CO-NH-Ar') synthesis. Furthermore, the DFT studies were also performed to support the proposed mechanism. � 2021
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    Synthesis and photophysics of new unsymmetrically substituted 5,5′-diaryl-2,2′-bypiridine-based “push-pull” fluorophores
    (Elsevier, 2019) Starnovskaya, E.S; Kopchuk ,D.S; Khasanov, A.F; Tanya, O.S; Santra, S; Giri, Kousik; Rahman, M; Kovalev, I.S; Zyryanov, G.V; Majee, A; Charushin, V.N.,
    New unsymmetrically substituted 5,5′-diaryl-2,2′-bypiridine “push-pull” fluorophores were prepared in good yields via the “1,2,4-triazine method”/Suzuki coupling reaction sequence. The obtained fluorophores contain the “push-pull” system with donor and acceptor moieties arranged in a D-π-A-π-D fashion, and that provides both the prospective photophysical properties and unique solvatocromic effects for the most representative compounds. © 2018 Elsevier Ltd