• Abhijit Chatterjee

      Articles written in Journal of Chemical Sciences

    • Molecular orbital calculations on [HRu3(CO)9(PhNCO)] and related clusters

      Sumit Bhaduri Abhijit Chatterjee Sourav Pal Shilpa Tawde Doble Mukesh

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      Molecular orbital calculations (EHMO) have been performed on five ruthenium carbonyl clusters considered to be involved in the reductive carbonylation of nitrobenzene. The bonding in the isocyanate cluster, [HRu3(CO)9(HNCO)], is shown to arise mainly from the interaction between the LUMO of HNCO and HOMO of the [HRu3(CO)9] fragment. The relative stabilities of this cluster, two of its isomers and the CO-eliminated cluster [HRu3(CO)9(HN)], are also commented upon. The calculated results are in accordance with empirical kinetic data.

    • Application of localized reactivity index in combination with periodic DFT calculation to rationalize the swelling mechanism of clay type inorganic material

      Abhijit Chatterjee

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      Clays are layered alumino-silicates. Clays swell and expand in aqueous solution. This property governs the usage of these materials in synthesis of nano-composites and is a source of many of its catalytic applications. We used both localized and periodic calculations within the realm of density functional theory (DFT) on a series of monovalent (Li+, Na+, K+, Rb+, Cs+), and divalent (Mg2+, Ca2+, Sr2+, Ba2+) cations, to monitor their effect on the swelling of clays. The activity order obtained for the exchangeable cations among all the monovalent and divalent series studied is: Mg2+ > Ca2+ > Sr2+ > Ba2+ > Cs+ > Rb+ > Na+ > Li+ > K+. We have studied two types of clays, montmorillonite and beidellite, with different surface structures and with/without water using periodic calculations. We have calculated the layer spacing at the first, second and third hydration shells of exchangeable cation, to compare with the experimentald-spacing values to correlate with humidity. A novel quantitative scale is proposed in terms of the intermolecular relative nucleophilicity of the active cation sites in their hydrated state through Fukui functions using hard-soft acid base (HSAB) principle. Finally, a swelling mechanism is proposed. This is a unique study where a combination of periodic and localized calculations has been performed to validate the capability of reactivity index calculations in material designing.

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