• Debes K Das

      Articles written in Journal of Chemical Sciences

    • Study of trends in charge-transfer absorption maxima of some π-type molecular complexes using graph-theoretical techniques

      Debes K Das Asok K Mukherjee Ivan GUutman

      More Details Abstract Fulltext PDF

      The change in charge-transfer absorption maxima of the π-type molecular complexes formed between chloranil and a series of phenols with varying number and position of the phenolic OH group(s) is shown to follow a certain trend. For this purpose the Coulson-Longuet-Higgins method in HMO formalism is used. The necessary eigenvector components are computed by employing a recently developed graph-theoretical technique, which avoids the calculation of the unnecessary eigenvectors. From the trends in the charge-transfer bands, the perturbational HMO parametersh andk for the phenolic oxygen and the C(sp2)-0 bond, respectively, were obtained in a straightforward way and found to be in good agreement with previously recommended values, determined by other methods.

    • Graph-theoretical calculation of products of eigen coefficients: Some application to charge-transfer complexes

      Asok K Mukherjee Debes K Das

      More Details Abstract Fulltext PDF

      A graph-theoretical formula for computation of products of eigen coefficientsCrjCsj(r≠s) of a graph has been derived. A general formula for the characteristic polynomial of a linear chain having a branch with a weighted pendant vertex has been given. These have been utilised, together with the Ulam subgraph method for obtaining squares of eigen coefficients, to take into account the perturbations in Coulomb and resonance integrals due to introduction of heteroatoms in a conjugated system or due to attachment of Me groups to conjugated atoms. Heteroatom Hückel parametersh andk of N and Me groups have been estimated and some structural information about a number of electron donors have been extracted by applying the results to the trends in the charge-transfer bands of their π-type molecular complexes.

  • Journal of Chemical Sciences | News

© 2021-2022 Indian Academy of Sciences, Bengaluru.