Pratim Kumar Chattaraj
Articles written in Journal of Chemical Sciences
Volume 117 Issue 5 September 2005 pp 541-548
Adsorption of small molecules like CH4, CO and NH3 into the acid sites of zeolites is analysed as an interaction between an electrophile and a nucleophile. Global reactivity descriptors like softness and electrophilicity, and local reactivity descriptors like the Fukui function, local softness and local philicity are calculated within density functional as well as Hartree-Fock frameworks using both Mulliken and Hirshfeld population analysis schemes. The HSAB principle and the best electrophile-nucleophile combination suggest that the reaction between the NH3 and Brönsted acid site of the zeolite is the strongest. Interaction between the zeolite and a small probe molecule takes place through the most electrophilic atom of one with the most nucleophilic atom of the other. This result is in conformity with those provided by the frontier orbital theory and the local HSAB principle.
Volume 124 Issue 1 January 2012 pp 29-34
The chemical reactivity descriptors, such as electronegativity, hardness and electrophilicity of major oxides computed from density functional theory are reported in this paper. These parameters are plotted within a fitness landscape diagram, showing that the principles of minimum electrophilicity (MEP) and maximum hardness (MHP) act as guides towards the region of higher stability. The diagrams indicate the trends and the parameters that control the evolution of natural rocks. Application of the principle S-bearing copper compounds shows the possible and preferred combinations of elements, that give rise to compounds observed during ore formation.
Volume 128 Issue 10 October 2016 pp 1537-1548 Regular Article
A density functional theory based study is performed to investigate the noble gas (Ng = Ar-Rn) binding ability of nitrates, sulfates and carbonates of noble metal (M). Their ability to bind Ng atoms is assessed through bond dissociation energy and thermochemical parameters like dissociation enthalpy and dissociation free energy change corresponding to the dissociation of Ng bound compound producing Ngand the respective salt. The zero-point energy corrected dissociation energy values per Ng atom for the dissociation process producing Ng atom(s) and the corresponding salts range within 6.0–13.1 kcal/mol in NgCuNO₃, 3.1–9.8 kcal/mol in NgAgNO₃, 6.0–13.2 kcal/mol in NgCuSO₄, 3.2–10.1 kcal/mol in NgAgSO₄, 5.1–11.7 kcal/mol in Ng₂Cu₂SO₄, 2.5–8.6 kcal/mol in Ng₂Ag₂SO₂, 8.1–19.9 kcal/mol in Ng₂Au2SO₂, 5.7–12.4 kcal/mol in NgCuCO₃, 2.3–8.0 kcal/mol in Ng₂Ag₂CO₃ and 7.3–18.2 kcal/mol in Ng₂Au₂CO₃, with a gradual increase in moving from Ar to Rn. For a given type of system, the stability of Ng bound analogues follows the order as Au > Cu > Ag. All dissociation processes are endothermic in nature whereas they become endergonic as well in most of the cases of Kr-Rn bound analogues at 298 K. Natural population analysis along with the computation of Wiberg bond indices, and electron density analyses provide insights into the nature of the Ng-M bonds. The Ng-M bonds can be represented as partial covalent bonds as supported by the different electron density descriptors.
Volume 134 All articles Published: 25 January 2022 Article ID 0014
The activation of the C-F bond in 1-fluorobutane, 1, 1-difluorobutane and 1, 1, 1-trifluorobutaneby some frustrated Lewis pair (FLP) has been assessed by DFT based computational study. The FLPs areconstructed from lutidine Lewis base in association with either B(C6F5)3 or Al(C6F5)3. Thermodynamics andkinetics of the reactions are studied, which reveals the concerning bond activation mediated by the Al(C6-F5)3/lutidine FLP is more favourable than the analogous reactions mediated by the B(C6F5)3/lutidine pair.Therefore, the Al(C6F5)3 acid is superior to the B(C6F5)3 acid to construct an effective FLP for some unusualbond activation. The EDA-NOCV study together with the WBI calculation reveals the C-F bond activation inthe studied systems takes place by the cooperative action of the FLP partners. The activation strain modelreveals the strain energy of the reactants to reach the transition state (TS) rather than the interaction energy atthe TS is the decisive factor to the TS barrier height of the concerned reactions.
The activation of C-F bond in 1-fluorobutane, 1, 1-difluorobutane and 1, 1, 1-trifluorobutane by B(C6F5)3/lutidine and Al(C6F5)3/lutidine pairs has been assessed computationally. The Al(C6F5)3/lutidine pair is superior to the B(C6F5)3/lutidine pairs for such unusual bond activation as revealed by this study.
Volume 134, 2022
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