title: The mutual interactions based on amphipathic tetraoxacalix[2]arene[2]triazine: recognition cases of anion and cation investigated by a computational study.
abstract: The nature of anion···π (anion X1-4(-) = SCN(-), PF6(-), BF4(-) and NO3(-), respectively) interactions with electron-deficient and cavity self-tunable macrocyclic host tetraoxacalix[2]arene[2]triazine 1 as electron-acceptor (J. Am. Chem. Soc., 2013, 135, 892) have been theoretically investigated with the density functional theory (B3LYP, M06-2X, M06-L, M06, M05-2X, M05, DFT-D3) and the second-order Møller-Plesset perturbation theory (MP2) using a series of basis sets. The binding energies calculated are in good quantitative agreement with the experiments. The LMO-EDA (local molecular orbital energy decomposition analysis) results show that the major contributors of anion···π are electrostatic. The alkali metal cations M(+) (Na(+), K(+)) and alkaline earth metal cations M(2+) (Mg(2+), Ca(2+)) can also interact with 1 and, the cation···π binding of M(2+)···1 is stronger than that of M(+)···1, as well as their strength is gradually decreased along with an increase in the radius of M(+,2+). The investigation of interplay between the anion···π and the cation···π shows that the interactions among three-body, X(-), 1 and M(+) is varied with different phases. The polar solvent can strongly reduce the strength of the interaction, and the more increased the solvent polarity, the more reduced is the binding energy.
authors.affiliation: College of Life Science and Chemistry, Key Laboratory for New Molecule Design and Function of Gansu Universities, Tianshui Normal University, Tianshui 741001, China. zflitsnu@163.com.
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Li
authors.forename: Hui-Xue
authors.initials: HX
authors.lastname: Li
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Yang