1015084-03-3Relevant articles and documents
Cyanide ion complexation by a cationic borane
Chiu, Ching-Wen,Gabbai, Francois P.
, p. 814 - 817 (2008)
While we have previously reported that [1-(Mes2B)-8-(Me 3NCH2)-C10H6]+ ([2] +) complexes fluoride ions to form [1-(Mes2FB)-8-(Me 3NCH2)-C10H6] (2-F), we now show that this cationic borane also complexes cyanide to form [1-(Mes 2(NC)B)-8-(Me3NCH2)-C10H 6] (2-CN). This reaction also occurs under biphasic conditions (H2O-CHCl3) and may serve to transport cyanide in organic phases. The zwitterionic cyanoborate 2-CN has been fully characterized and its crystal structure determined. UV-vis titration experiments carried out in THF indicate that [2]+ has a higher affinity for fluoride (K > 10 8 M-1) than cyanide (K = 8.0 (±0.5) × 10 5 M-1). Steric effects which impede cyanide binding to the sterically congested boron center of [2]+ are most likely at the origin of this selectivity. Finally, electrochemical studies indicate that [2]+ is significantly more electrophilic than its neutral precursor 1-(Mes2B)-8-(Me2NCH2)-(C10H 6) (1). These studies also show that reduction of [2]+ is irreversible, possibly because of elimination of the NMe3 moiety under reductive conditions. In fact, [2]OTf reacts with NaBH4 to afford 1-(Mes2B)-8-(CH3)-(C10H6) (4) which has also been fully characterized. The Royal Society of Chemistry.
