Stabilization of intermediate cationic species derived from silylium induced C-F bond activation

FLUO 7

Christos Douvris, christod@ucr.edu, Department of Chemistry, University of California, Riverside, Riverside, CA 92521 and Christopher A. Reed, chris.reed@ucr.edu, Center for S and P Block Chemistry, Department of Chemistry, University of California at Riverside, Riverside, CA 92521.
The pursuit to find reliable and efficient methods for the activation of C-F bonds (the strongest single bond that carbon can form) continues to attract widespread interest1. While the utility of halophilic trialkysilylium species for this purpose has recently been reported2, the interaction of fluorocarbons with “silylium ion-like” species coupled with chemically robust carborane anions such as [Et3Si+][CHB11Cl11-] has not been explored. We now report that inert carborane anions of the type [CHB11Y5X6-] (X, Y = H, halogen, methyl or a combination of them), weakly interacting with superstrong-electrophilic [R3Si+] species (R = alkyl), in addition to their ability to cleave the highly strong C-F bonds of fluorocarbons, also permit the stabilization, isolation and crystallographic characterization of cationic reaction intermediates. For example, the new [(C6H4F)2(C6F4Me)C+ ] cation was isolated from a room temperature reaction between [Et3Si+][CHB11Cl11-] and C6F4MeCF3 in C6H5F solution.

1. Chem. & Eng. News January 30, 2006, p 36, 2. J. Am. Chem. Soc., 2005, 127, 2852

 

General Papers
1:30 PM-4:45 PM, Sunday, 10 September 2006 San Francisco Marriott -- Salon 5, Oral

Division of Fluorine Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006