(Fluoroorgano)fluoroboranes and -borates. 16. Preparation of bis(perfluoroalkyl)dimethoxyborate and bis(perfluoroalkyl)difluoroborate salts, M[(CnF2n+1)(2)BX2] (M = K, NMe4; X = OMe, F)

摘要

Potassium bis(perfluoroalkyl)dimethoxyborate salts, K[(CnF2n+1)(2)B(OMe)(2)] (n = 3, 4, 6), were prepared in 60-76% yield by the reaction of (perfluoroalkyl)lithium with chlorodimethoxyborane and subsequent metathesis of the cation with KF. Reactions of K[(CnF2n+1)(2)B(OMe)(2)] with 42-73% aqueous HF resulted in the salts K[(CnF2n+1)(2)B(OR)F] (R = H, CH3), which were converted into K[(CnF2n+1)(2)BF2] by the treatment with anhydrous HF. Metathesis of potassium salts with [NMe4]OH in water yielded the corresponding borates [NMe4][(CnF2n+1)(2)BF2].