Preparation and boron-11 and proton nuclear magnetic resonance study of the anions [B9H14]–, [B9H13(NCS)]–, and [B9H13(NC)BH3]–, and a comparison with the neutral derivatives B9H13(SMe2), B9H13(SEt2), and B9H13(CH3CN); isolation of [B8H12(NCS)]–

Abstract

The structure and fluxional character of derivatives of [B₉H₁₄]^– containing anionic or neutral ligands has been investigated by high-field ¹¹B and ¹H n.m.r. spectroscopy. The anionic derivatives [B₉H₁₃(NCS)]^– and [B₉H₁₃(NC)BH₃]^– showed significant dynamic and structural differences from those of the parent ion [B₉H₁₄]^– or the neutral compounds B₉H₁₃(SMe₂), B₉H₁₃(SEt₂), and B₉H₁₃(CH₃CN). The synthesis of the anionic derivatives led to interesting side-reactions in which [B₈H₁₂(NCS)]^– was produced and the dual chemical character of [BH₃(CN)]^– was illustrated as both a two-electron σ-donor ligand and hydride-transfer reagent.