Spectroscopic and Chemical Properties of the Cyanotrihydroborate Anion

The preparation of the potassium salt of the cyanotrihydroborate anion (KBH3CN) is reported and a procedure for obtaining high-purity cyanotrihydroborate salts is outlined. The infrared and Raman spectra of BH3CN- and cyanotrideuterioborate (BD3CN-) are reported and the fundamental frequencies are assigned. The nmr and infrared data for this species are used to make qualitative comparisons of the bonding and structures of BH3CN- and other BH3X adducts. The behavior of KBH3CN in strongly acidic and neutral aqueous solutions is examined. K-b for hydrolysis of KBH3CN is found to be approximately 10(-10). Attempted reductions of the cationic species Ag+, Hg2+, Cu2+, and Fe(CN)(3)(3-) by BH3CN- are discussed. A tentative mechanistic model for metal ion reduction is proposed and contrasted with that proposed for H+.