Tetraphenylboroxinate(1-) salts of monoborate cations: Synthesis and single-crystal X-ray structures of [Ph2B{OCH2CH2N(Me)(CH2)n}2][Ph4B3O3] (n = 4, 5)

The salts, [Ph2B{OCH2CH2N(Me)(CH2)n}2][Ph4B3O3] (n = 4, 5), were prepared in moderate yields in MeOH solution from reaction of Ph2BOBPh2 with [N(CH2)n(Me)(CH2CH2OH)][OH] and PhB(OH)2 in a 1:2:4 ratio. The reactions also lead to Ph3B3O3. Both salts were characterized by NMR (1H, 13C, 11B) IR, and single-crystal XRD studies. The salts are comprised of cationic monoborates (zwitterionic, 2N+ and 1B−) and tetraphenylboroxinate anions.

Graphical abstractThe zwitterionic (2N+, 1B−) monoborate cation is observed in the salts: [Ph2B{OCH2CH2N(Me)(CH2)n}2][Ph4B3O3] {n = 4, 5 (shown)}. The cation arises through condensation of a 2-hydroxyethyl substituted quaternary ammonium cation with a diphenylborinate moiety.Figure optionsDownload full-size imageDownload as PowerPoint slide