Synthesis and Characterization of Heteroleptic 1‑Tris(pyrazolyl)borate Beryllium Complexes

The synthesis and crystal structures of 1-tris­(pyrazolyl)­borate beryllium halides TpBeX (X = Cl 1, Br 2, I 3, F 4), the pyrazole adduct of TpBeF (5) and of 1-tris­(pyrazolyl)­borate beryllium hydride, deuteride and azide TpBeX (X = H 6, 2H (D) 7, N3 8; Tp = 1-trispyrazolylborate) is described. In addition, 9Be-NMR spectroscopy is introduced as suitable analytical tool for the in situ characterization of heteroleptic organoberyllium halides, pseudohalides and hydrides. Studies in different solvents and solvent mixtures allowed the formulation of a reference guide for the chemical shift of heteroleptic coordination complexes of beryllium only based on variation of the second substituent.