Influence of the Li⋅⋅⋅π Interaction on the H/X⋅⋅⋅π Interactions in HOLi⋅⋅⋅C₆H₆⋅⋅⋅HOX/XOH (X=F, Cl, Br, I) Complexes

Abstract

The influences of the Li···π interaction of C6H6···LiOH on the H···π interaction of C6H6···HOX (X=F, Cl, Br, I) and the X···π interaction of C6H6···XOH (X=Cl, Br, I) are investigated by means of full electronic second-order Møller-Plesset perturbation theory calculations and "quantum theory of atoms in molecules" (QTAIM) studies. The binding energies, binding distances, infrared vibrational frequencies, and electron densities at the bond critical points (BCPs) of the hydrogen bonds and halogen bonds prove that the addition of the Li···π interaction to benzene weakens the H···π and X···π interactions. The influences of the Li···π interaction on H···π interactions are greater than those on X···π interactions; the influences of the H···π interactions on the Li···π interaction are greater than X···π interactions on Li···π interaction. The greater the influence of Li···π interaction on H/X···π interactions, the greater the influences of H/X···π interactions on Li···π interaction. QTAIM studies show that the intermolecular interactions of C6H6···HOX and C6H6···XOH are mainly of the π type. The electron densities at the BCPs of hydrogen bonds and halogen bonds decrease on going from bimolecular complexes to termolecular complexes, and the π-electron densities at the BCPs show the same pattern. Natural bond orbital analyses show that the Li···π interaction reduces electron transfer from C6 H6 to HOX and XOH.

The competition of Y⋯o and X⋯n halogen bonds to enhance the group V σ-hole interaction in the NCY⋯oPH3⋯NCX and OPH3⋯NCX⋯NCY (X, YF, Cl, and Br) complexes

“…The applications of the Group V σ‐hole interactions in molecular recognition, crystal engineering, and biological systems are affected mainly by the strength and direction of the Group V σ‐hole interactions. The halogen bonds could display cooperative effect with other types of intermolecular interactions . Then, could the Group V σ‐hole interactions be strengthened by the addition of halogen bonds?…”

Mutual enhancing effects of the σ-hole interactions and halogen/hydrogen-bonded interactions in the iodine-ylide containing complexes

“…Additionally, the quantum theory of atoms in molecules (QTAIM) [42],which has been successfully characterize diverse kinds of noncovalent interactions [43,44], was employed to analyze the weakly bonded interactions under investigation. The topological analysis was carried out with the AIMAll program [45].The density difference in molecular formation was analyzed using Multiwfn software [46].…”

Cooperative and substitution effects in enhancing the strength of fluorine bonds by anion−π interactions

“…Like hydrogen bonds, cooperativity and substituent effects are also present among halogen bonds. Recently, the cooperativity between halogen bond and other types of interactions has been extensively studied [34][35][36][37]. For instance, Lu et al [38] found a strong cooperativity between halogen bonds and cation-π interactions in complexes involving aromatic molecules as halogen bond donors.…”