REACTIONS OF FLUORINE PERCHLORATE WITH FLUOROCARBONS AND THE POLARITY OF THE O-F BOND IN COVALENT HYPOFLUORITES

Although FOClO3 has been known for decades,1, 2 its reaction chemistry has remained virtually unexplored and is limited to references to unpublished work, cited in a review.3This lack of data is attributed to the previous report2 that FOClO3 consistently exploded during attempted freezing. During a study4 of NF4ClO4, it was found that very pure FOClO3 could be obtained in high yield by the thermal decomposition of NF4ClO4. The FOClO3, prepared in this manner, could be manipulated and repeatedly frozen without explosions, thus allowing us to study some of its properties5and reaction chemistry. Of particular interest to us were the reactions of FOClO3 with fluorocarbons. Previous work6 in our laboratory had demonstrated that ClOClO3 and BrOClO3 add readily to fluorocarbon double bonds, resulting in covalent fluorocarbon perchlorates. Consequently, one would expect fluorine perchlorate to undergo a similar reaction. However, a literature citation3 suggested that F0C1O3 does not add across the double bond in Cl2C̿CF2. Furthermore, reactions of covalent hypofluorites, such as CF3OF, are commonly interpreted in terms of a highly unusual CF3Ob--Fb+ type polarization of the O-F bond (“positive fluorine#x201D;). If the O-F bond in CF3OF is indeed polarized in this direction, the fluorine in F0ClO3should be even more positive because of the higher electronegativity of the perchlorato group. Since the direction of the addition of a hypohalite across an unsymmetrical olefinic double bond strongly depends on the direction and the degree of polarization of the O-Hal bond,7 a study of the O3C10F/CF3CF̿CF2 reaction system offered an ideal opportunity to experimentally test the validity of the “positive fluorine” concept. © 1979, American Chemical Society. All rights reserved.