Articles written in Journal of Chemical Sciences

    • Quantum chemical investigation of the reaction of O(${}^3P_2$) with certain hydrocarbon radicals

      Ashutosh Gupta R P Singh V B Singh Brijesh Kumar Mishra N Sathyamurthy

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      The reaction of ground-state atomic oxygen [O(${}^3P_2$)] with methyl, ethyl, 𝑛-propyl and isopropyl radicals has been studied using the density functional method and the complete basis set model. The energies of the reactants, products, reaction intermediates and various transition states as well as the reaction enthalpies have been computed. The possible product channels and the reaction pathways are identified in each case. In the case of methyl radical the minimum energy reaction pathway leads to the products CO + H2 + H. In the case of ethyl radical the most facile pathway leads to the products, methanal + CH3 radical. For propyl radical (𝑛- and iso-), the minimum energy reaction pathway would lead to the channel containing ethanal + methyl radical.

    • Modeling of 1-D Nanowires and analyzing their Hydrogen and Noble Gas Binding Ability


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      The theoretical calculation at the M05-2X/6-311+G(d,p) level reveals that the B–B bond length in [N ₄ ₋B ₂ ₋N ₄] ²⁻ system (1.506 Å) is slightly smaller than that of typical B=B bond in B ₂H ₂ (1.518 Å). These systems interact with each M ⁺ (M = Li, Na, K) ion very strongly with a binding energy of 213.5 (Li), 195.2 (Na) and 180.3 (K) kcal/mol. Additionally, the relief of the Coulomb repulsion due to the presence of counterion, M ⁺, the B–B bond contracts to 1.484–1.488Å in [N ₄ ₋B ₂ ₋N ₄]M ₂. We have further extended our study to [N ₄ ₋B ₂ ₋N ₄ ₋B ₂ ₋N ₄] ⁴⁻ and [N ₄ ₋B ₂ ₋N ₄-B ₂ ₋N ₄ ₋B ₂ ₋N ₄] ⁶⁻ systems. The B–B bond length is found to be 1.496Å in the former case, whereas the same is found to be 1.493Å and 1.508 Å, respectively, for the two B–B bonds present in the latter one. The M ⁺ counter-ions stabilize such negatively charged systems and thus, create a possibility to design a long 1-D nanowire. Their utilities as probable hydrogen and noble gas (Ng) binding templates are explored taking [N ₄ ₋B ₂2 ₋N ₄ ₋B ₂ ₋N ₄]Li ₄ system as a reference. It is found that each Li center binds with three H ₂ molecules with an average binding energy of 2.1 kcal/mol, whereas each Ng (Ar–Rn) atom interacts with Li center having a binding energy of 1.8–2.1 kcal/mol. The H ₂ molecules interact with Li centers mainly through equal contribution from orbital and electrostatic interaction, whereas the orbital interaction is found to be major term (ca. 51–58%) in Ng-Li interaction followed by dispersion (ca. 24–27%) and electrostatic interaction (ca. 17–24%).

    • Complexation of Mono-anionic Bidentate Ligand Dithiocarbamate with σ-Aromatic M3+ Clusters: A DFT Study


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      The present study deals with a computational investigation on the role of dithiocarbamate (DTC)anions in the stabilization of r-aromatic trinuclear mono-cationic metal clusters (M = Cu, Ag and Au).Electrostatic potential, aromaticity, binding energy, thermodynamical parameters and nature of bonding areestimated. Nucleus independent chemical shifts (NICS) and their variants such as NICStotal and FiPC-NICSare employed to calculate aromaticity. The nature of bonding is assessed by the quantum theory of atoms-inmolecules(QT-AIM) and NBO methods. The charge density map in the complex has been assessed bymolecular electrostatic potential analysis. Comparison of complexation properties of DTC ligand to commonmonodentate ligands (pyrazolates, NHC, pyridine, furan and isoxazole) explored in past reveal that DTCanions are more efficient in stabilizing metal complexes.

      A computational approach is undertaken to investigate complexation properties of dithiocarbamate (DTC) anions with electron-deficient M3+ (M = Cu, Ag and Au) clusters. DTC ligands are found to be efficient chelators as compared to commonly used monodentate ligands to bind and stabilize such unstable trinuclear mono-cationic metal clusters

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