title: Thermodynamics of halogen bonding in solution: substituent, structural, and solvent effects.
abstract: A detailed study of the thermodynamics of the halogen-bonding interaction in organic solution is presented. (19)F NMR titrations are used to determine association constants for the interactions of a variety of Lewis bases with fluorinated iodoalkanes and iodoarenes. Linear free energy relationships for the halogen bond donor ability of substituted iodoperfluoroarenes XC(6)F(4)I are described, demonstrating that both substituent constants (sigma) and calculated molecular electrostatic potential surfaces are useful for constructing such relationships. An electrostatic model is, however, limited in its ability to provide correlation with a more comprehensive data set in which both halogen bond donor and acceptor abilities are varied: the ability of computationally derived binding energies to accurately model such data is elucidated. Solvent effects also reveal limitations of a purely electrostatic depiction of halogen bonding and point to important differences between halogen bonding and hydrogen bonding.
authors.affiliation: Department of Chemistry, Lash Miller Chemical Laboratories, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Mohammed G
authors.initials: MG
authors.lastname: Sarwar
authors.forename: Bojan
authors.initials: B
authors.lastname: Dragisic
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Salsberg
authors.forename: Christina
authors.initials: C
authors.lastname: Gouliaras
authors.forename: Mark S
authors.initials: MS
authors.lastname: Taylor
mesh_terms: D006219:Halogens / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D006219:Halogens; D012996:Solutions; D012997:Solvents