Polyfluoroorganoboron-Oxygen Compounds. 7. Studies of Conversion of [(C6HnF5-n)B(OMe)3]- Into [(C6HnF5-n)2B(OMe)2]- (n = 0, 1)

Conversion of salts Li[(C6HnF5-n)B(OMe)3] (n = 0, 1) into (Li·DME)[(C6HnF5-n)2B(OMe)2] was studied in dichloromethane-DME solution. The observed rate constants k decrease from (21.4 ± 0.9) × 10-3 l mol-1 s-1 (Li[C6F5B(OMe)3]) over (6.99 ± 0.11) × 10-3 l mol-1 s-1 (Li[(2,3,5,6-C6HF4)B(OMe)3]) to (2.94 ± 0.05) × 10-3 l mol-1 s-1 (Li[(2,3,4,6-C6HF4)B(OMe)3]), while Li[(2,3,4,5-C6HF4)B(OMe)3] does not undergo any transformation. Hydrolysis of (Li·DME)[(C6HnF5-n)2B(OMe)2] leads to corresponding borinic acids, whereas treatment of them with aqueous solution of M[HF2] (M = Bu4N, K) acidified with HF results in M[(C6HnF5-n)2BF2] in high yields.