A DFT investigation of the host-guest interactions between boron-based aromatic systems and β-cyclodextrin

Density functional theory calculations including dispersion at BLYP-D3(BJ)/def2-SVP level of theory were performed for a series of systems based on cyclodextrin complexation with boron-based aromatic compounds. Elaborated investigations were carried out using different quantum chemical parameters such as computed complexation energies, theoretical association constants, and natural bond orbital (NBO) analysis. Several configurations and inclusion modes were considered in this work. The calculated complexation energies were consistent with the experimental classification of these systems on the basis of occurring interactions. Reduced density gradient (RDG) and independent gradient model (IGM) approaches determined the nature and strength of non-covalent interactions which played a central role in the formation of the complexes. Thus, phenylboronic acid (PBA) and benzoxaborole (Bxb) act mainly as hydrogen-bonded complexes with beta-cyclodextrin, while mainly Van der Waals (vdW) interactions stabilize both catechol (PhBcat) and pinacol esters of phenylboronic acid (PhBpin) complexes. The ferroceneboronic acid (FcBA) exhibits a mixture of H-bonds and vdW interactions with beta-cyclodextrin.