The Microwave Spectra and Molecular Structures of Vinyl Fluoride Ozonide and Vinylidene Fluoride Ozonide.

The rotational spectra of twelve isotopic species of vinyl fluoride ozonide (3-fluoro-1,2,4-trioxolane, I) and seven species of vinylidene fluoride ozonide (3,3-difluoro-1,2,4-trioxolane, II) were assigned. These included all of the possible single-deuterium substituted species of both compounds, five ('18)O substituted species of I and four ('18)O species of II, and the triple-deuterium and both single-('13)C substituted species of I. The structure of I was analysed by both least-squares (r(,o)) and Kraitchman's substitution (r(,s)) methods. The presence of a numberof small coordinates made the r(,s) structure somewhat inaccurate, and the r(,o) structure was chosen as the best of those obtained. Theoverall structure is a five membered ring (FCHOOHCHO) with a(' )conformation intermediate between an O-O twist and an O(peroxy,CH(,2)) envelope, with an axial fluorine substituent. Some of the significant structural parameters are: r(O(,ether)-C(,H)) = 1.426(5) (ANGSTROM); r(O(,e)-C(,F)) = 1.382(10) (ANGSTROM); r(C(,H)-O(,peroxy)) = 1.411(5) (ANGSTROM); r(C(,F)-O(,p)) = 1.382(10) (ANGSTROM); r(O-O) = 1.463(5) (ANGSTROM); r(C-F) = 1.375(5) (ANGSTROM); (ANGLE) C-O-C = 105.3(4)(DEGREES); (ANGLE) O-C(,F)-O = 107.6(4)(DEGREES); (ANGLE) O-C(,H)-O = 101.1(3)(DEGREES); (ANGLE) C(,H)-O-O = 104.6(2)(DEGREES); (ANGLE) C(,F)-O-O = 99.3(3)(DEGREES); (ANGLE) C-O-O-C = 46.0(DEGREES); O-C(,H)-O-O = 40.4(DEGREES); (ANGLE) O-C(,F)-O-O = 35.0(DEGREES); (ANGLE) F-C-O-O = 83.5(DEGREES). The uncertainties represent one st and ard deviation. An insufficient number of isotopic species of II were assigned to permit a complete structural determination by either of the above means. Bartell's method of predicate observables was used in this case, based on the available data, the structure of I, and extrapolated structural trends. The ring conformation of II is very close to a pure O(peroxy,CH(,2)) envelope, with a C-O(,e)-C(,F)-O dihedral angle of only 2 (+OR-) 4(DEGREES). The following structural parameters were obtained: r(O(,e)-C(,H)) = 1.425(25) (ANGSTROM); r(O(,e)-C(,F)) = 1.368(20) (ANGSTROM); r(C(,H)-O(,p)) = 1.404(20) (ANGSTROM); r(C(,F)-O(,p)) = 1.360(25) (ANGSTROM); r(O-O) = 1.467(10) (ANGSTROM); (ANGLE) C-O-C = 103.9(DEGREES); (ANGLE) O-C(,F)-O = 110.5(DEGREES); (ANGLE) O-C(,H)-O = 103.5(DEGREES); (ANGLE) C(,H)-O-O = 99.4(DEGREES); (ANGLE) C(,F)-O-O = 101.8(DEGREES); (ANGLE) F-C-F = 105.1(DEGREES); (ANGLE) C-O-O-C = 42(DEGREES); (ANGLE) F(,axial)-C-O-O = 96(DEGREES). The structures of I and II are both analysed in terms of the anomeric effect. In both molecules this effect is seen (a) by the shortening of the C(,F)-O bonds, (b) by the lengthening of the C-F(axial) bond, and (c) by the near 90(DEGREES) F-C-O-O dihedral angles.Ph.D.Physical chemistryUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158462/1/8125130.pd