title: Infrared spectra of SF6-.(H2O)n (n=1-3): incipient reaction and delayed onset of water network formation.
abstract: We present data on the microsolvation of an extended charge distribution with SF(6)(-) as a model system. Infrared spectroscopy, aided by ab initio calculations, shows that the first two water molecules attach to the ion by a combination of single ionic H bonds, sharing one of the F atoms, and weak electrostatic interactions with other F atoms in the ion. No water-water bonds are formed at the dihydrate level, which is an unusual observation, given the strong propensity of water to form H-bonded networks. The onset of water networks occurs with the addition of the third water molecule. Moreover, the attachment of the first two water molecules considerably weakens the SF bond of the F atom involved in bonding to both ligands, indicating a possible mechanism for water-induced reactions.
authors.affiliation: JILA, NIST, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Holger
authors.initials: H
authors.lastname: Schneider
authors.forename: J Mathias
authors.initials: JM
authors.lastname: Weber
mesh_terms: D004735:Energy Transfer; D005461:Fluorine / Q000737:chemistry; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D008958:Models, Molecular; D017785:Photons; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D055672:Static Electricity; D013459:Sulfur Hexafluoride / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D007477:Ions; D012997:Solvents; D014867:Water; D005461:Fluorine; D013459:Sulfur Hexafluoride