title: Influence of substituents on the nature of metal⋯π interaction and its cooperativity with halogen bond.
abstract: High-level quantum chemical calculations have been performed to investigate the influence of substituents on the metal-π interaction and its cooperative effect with halogen bond in C2X4⋯MCN⋯ClF (X = H, CN, CH3; M = Cu, Ag, Au). The strong electron-withdrawing group CN weakens the metal-π covalent interaction, while the weak electron-withdrawing group CH3 strengthens it. The metal-π covalent interaction is dominated by electrostatic energy although the AuCN complex has approximately equal electrostatic and polarization contributions. However, the metal-π covalent interaction is governed by polarization energy due to the CN substitution. A cooperative effect is found for the halogen bond and metal-π interactions in C2H4⋯MCN⋯ClF, while a diminutive effect occurs in the triads by the CN substituent. Orbital interaction analysis indicates that the strong electron-withdrawing group CN causes the C=C group vary from a stronger donor orbital to a stronger acceptor orbital.
authors.affiliation: The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Gao
authors.affiliation: The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Cheng
authors.affiliation: The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
authors.forename: Wenzuo
authors.initials: W
authors.lastname: Li
authors.affiliation: The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Xiao
authors.affiliation: The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
authors.forename: Qingzhong
authors.initials: Q
authors.lastname: Li