In recent years, it has become a strategy, and important area of research, to incorporate heteroatom into polycyclic aromatic compounds. Especially B/N containing aromatic compounds have been the topic of interest over the years, because of the isoelectronic nature of B–N bond with C=C bond. The substitutionof B–N in place of C=C brings many important electronic and structural changes in the system. This work presents the investigation of the interaction between different cations and the π-cloud of the 1,2-dihydro-1,2-azaborine molecule using quantum chemical investigations at the MP2/aug-cc-pVDZ level of theory. The nature of interactions has been gauged by employing the energy decomposition analysis and molecular electron density critical point calculations. Further, the changes in N–H, B–H and C–H bond vibrational frequencies due to thecation binding were also investigated. Among the cations studied in this work, Be 2+ is found to provide the best compromise between size and charge as revealed by its high interaction energy and presence of electron density three critical points.

Hydrogen-bonded complexes between xylose and water, modelled by xylofuranose…H₂O complexes were explored employing ab initio quantum chemical framework. The Møller–Plesset secondorder perturbation theory (MP2) in conjugation with aug-cc-pVDZ basis set, is used for investigating the H-bonding interactions. The complete basis set limit interaction energies for a-and b-xylofuranose and xylopyranose water complexes were calculated at MP2 level. It is observed that the addition of water molecule does not change the conformational structure of xylose moieties. Further water is found to interactwith xylose mainly through the O atom present in a ring and its neighboring OH group. Energy decomposition analysis by LMO-EDA approach indicates that the electrostatic and exchange interactions are the two largest contributing terms to the total interaction energy for bonding between Xylose and water