title: Do traditional, chlorine-shared, and ion-pair halogen bonds exist? An ab initio investigation of FCl:CNX complexes.
abstract: Ab initio MP2/aug'-cc-pVTZ calculations have been carried out to determine the structures, binding energies, and bonding of complexes FCl:CNX, with X = CN, NC, NO(2), F, CF(3), Cl, Br, H, CCF, CCH, CH(3), SiH(3), Li, and Na. Equation-of-motion coupled cluster calculations have also been carried out to determine the coupling constants (1)J(F-Cl), (1X)J(Cl-C), and (2X)J(F-C) across these halogen bonds. As the strength of the base is systematically increased, the nature of the halogen bond changes from traditional, to chlorine-shared, to ion-pair. The type of halogen bond present in a complex can be readily determined from its structure, binding energy, AIM bonding analyses, and spin-spin coupling constants. Coupling constants across halogen bonds are compared with corresponding coupling constants across traditional, proton-shared, and ion-pair hydrogen bonds.
authors.affiliation: Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, USA. jedelbene@ysu.edu
authors.forename: Janet E
authors.initials: JE
authors.lastname: Del Bene
authors.forename: Ibon
authors.initials: I
authors.lastname: Alkorta
authors.forename: José
authors.initials: J
authors.lastname: Elguero
mesh_terms: D002244:Carbon / Q000737:chemistry; D003486:Cyanides / Q000737:chemistry; D006219:Halogens / Q000737:chemistry*; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D008672:Metals, Alkali / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D011522:Protons; D014732:Vibration
chemical_list: D003486:Cyanides; D006219:Halogens; D007477:Ions; D008672:Metals, Alkali; D011522:Protons; D002244:Carbon; D009584:Nitrogen