Torsional Rotation in Ditopic Receptor Host and its Complex Formation with Resorcinol Guest: A Computational Study

Abstract

AbstractNoncovalent interactions due to the presence of heteroatoms in supramolecular compounds have gained a lot of attention. These different heteroatom‐based supramolecular compounds have inspired us to examine the noncovalent interaction in the isolated host and host‐guest complexes. In view of this, in the current manuscript, we investigated the stability and torsional energy barrier of different conformers of the ditopic receptor host 1,6‐bis(2,6‐bis(benzothiazol‐2‐yl) pyridine‐4‐yloxy) hexane (bbh). The conformer that is accompanied by intramolecular C−H⋯N and C−H⋯S interactions is relatively more stable than the others. Due to torsional angle rotation within the host, the C−H⋯N and C−H⋯S interactions get disrupted and exhibit different binding sites for capturing guest molecules. In addition, we have extended the investigation to understand the interaction energy and nature of interaction in host‐guest (1 : 1 and 1 : 2) complexes formed between the host (bbh) and guest (resorcinol) by using different DFT functionals. Extended transition state‐natural orbital chemical valence (ETS‐NOCV) analysis of complexes revealed that the electrostatic interaction significantly contributes to the host‐guest interaction energy. The noncovalent (NCI) analysis provides the existence of intermolecular hydrogen bonding and other weak interactions within the complexes.