title: Structural and conformational properties of fluoroformic acid anhydride, FC(O)OC(O)F.
abstract: The conformational properties and geometric structures of fluoroformic acid anhydride, FC(O)OC(O)F, have been studied by vibrational spectroscopy, gas electron diffraction (GED), single-crystal X-ray diffraction, and quantum chemical calculations (HF, MP2, and B3LYP methods with 6-31G* and B3LYP/6-311+G* basis sets). Satellite bands in the IR matrix spectra, which increase in intensity when the matrix gas mixture is heated prior to deposition as a matrix, indicate the presence of two conformers at room temperature. According to the electron diffraction analysis, the prevailing conformer is of C(2) symmetry with both C=O bonds synperiplanar with respect to the opposite C-O bond ([sp, sp] conformer). The minor conformer [15(5)% from IR matrix and 6(11)% from GED] is predicted by quantum chemical calculations to possess an [sp, ac] structure. FC(O)OC(O)F crystallizes in the orthorhombic system in the space group P2(1)2(1)2(1) with a = 6.527(1) angstroms, b = 7.027(1) angstroms, and c = 16.191(1) angstroms and four formula units per unit cell. In the crystal, only the [sp, sp] conformer is present, and the structural parameters are very similar to those determined by GED.
authors.affiliation: Institut für Physikalische und Theoretische Chemie, Universität Tübingen, D-72076 Tübingen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Mayer
authors.forename: Heinz
authors.initials: H
authors.lastname: Oberhammer
authors.forename: Michael
authors.initials: M
authors.lastname: Berkei
authors.forename: Holger
authors.initials: H
authors.lastname: Pernice
authors.forename: Helge
authors.initials: H
authors.lastname: Willner
authors.forename: Karina
authors.initials: K
authors.lastname: Bierbrauer
authors.forename: Maximiliano Burgos
authors.initials: MB
authors.lastname: Paci
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Argüello