Enhancing effects of electron-withdrawing groups and metallic ions on halogen bonding in the YC6F4X···C2H8N2 (X = Cl, Br, I; Y = F, CN, NO2, LiNC+, NaNC+) complex.
Halogen-bonding interactions are highly directional intermolecular interactions that are often important in crystal engineering. In this work, the second-order Møller-Plesset perturbation theory (MP2) calculations and the quantum theory of "atoms in molecules" (QTAIM) and noncovalent interaction (NCI) studies were carried out on a series of X···N halogen bonds between substituted haloperfluoroarenes C6F4XY (X = Cl, Br, I; Y = F, CN, NO2) as bond donors and 1,2-diaminoethane as bond acceptor. Our research supports earlier work that electron-withdrawing substituents produce an enhancement effect on the size of the σ-hole and the maximum positive electrostatic potentials (VS,max), which further strengthens the halogen bonding. The metallic ion M(+) (M(+) = Li(+), Na(+)) has the ability to enhance the size of both the σ-hole and VS,max value with the formation of [MNCC6F4X](+), resulting in more electronic charge transfer away from the halogen atom X and an increase in the strength of the halogen bond. It is found that the values of V(S,max) at the σ-holes are linear in relation to the halogen-bonded interaction energies and the halogen-bonding interaction distance, indicating that the electrostatic interaction plays a key role in the halogen-bonding interactions. The values of V(S,max) at the σ-holes are also linear in relation to the electron density ρ(b), its Laplacian nabla(2)ρb, and -Gb/Vb of XB, indicating that the topological properties (ρb, nabla(2)ρb) and energy properties (Gb, Vb) at the BCPs are correlated with the electrostatic potentials.
Institute of Computational Quantum Chemistry, College of Chemistry and Material Science, Hebei Normal University , Shijiazhuang 050024, PR China.
Na
N
Han
Yanli
Y
Zeng
Xiaoyan
X
Li
Shijun
S
Zheng
Lingpeng
L
Meng
D003486:Cyanides / Q000737:chemistry*; D004583:Electrons; D006219:Halogens / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D009585:Nitrogen Dioxide / Q000737:chemistry*; D011789:Quantum Theory; D012964:Sodium / Q000737:chemistry*
D003486:Cyanides; D006219:Halogens; D007477:Ions; D008094:Lithium; D012964:Sodium; D009585:Nitrogen Dioxide