Gauging ambiphilicity of pseudo-halides via beryllium-trispyrazolylborato compounds

Abstract

The ambiphilicity of pseudo-halides has been the object of extensive debate. Herein, we use a series of trispyrazolylborato beryllium pseudo-halido complexes [TpBe(X′)] with X′ = CN⁻, N₃⁻, NCO⁻ and NCS⁻ to explore the origins of the preferred isomers. Thus, we have synthesised and characterised through NMR and IR spectroscopy as well as single crystal X-ray diffraction these complexes. A combination with quantum chemical calculations within the DFT framework enabled an in-depth understanding of the bonding modes and preferences of the investigated pseudo-halido ligands.