Synthesis and characterization of templated pentaborate(1-) salts: X-ray structure of [(2-HOCH₂CH₂)C₄H₇NMeH][B₅O₆(OH)₄]·0.3H₂O

GRAPHICAL ABSTRACT

ABSTRACT

The synthesis of pyrrolidinium pentaborate(1-) and four substituted pyrrolidinium pentaborate(1-) salts from B(OH)₃ in aqueous solution are reported. Characterization (Infrared, nuclear magnetic resonance, and single-crystal X-ray power diffraction) of [(2-HOCH₂CH₂)C₄H₇NH₂] [B₅O₆(OH)₄]0.3H₂O is described in detail. The cation is the largest of the five pyrrolidinium cations studied. A consequence of this is that its solid-state structure has anion–anion interactions (αααγ), which are different from the other four (αααβ) structures. There are also stabilizing cation–anion H-bond interactions.

KEYWORDS:

• Pentaborate(1-)
• H-bonds
• pyrrolidinium
• X-ray structure
• oxidoborate

Acknowledgment

We thank the EPSRC for use of the NCS Service.