Tungsten Tris(pyrazolyl)borate Cage Expansion by Formal Insertion of an Alkylidyne Group into a Tungsten-Nitrogen Bond

摘要

Attempts to achieve alkylidyne-imido or -oxo coupling resulted in the formal insertion of an alkylidyne group into one of the W-N single bonds of a tungsten tris(pyrazolyl)-borate cage. It can be expected that similar insertion reactions of alkylidyne ligands will occur with other σ-bonded ligands. This work also shows that tris(pyrazolyl)borate ligands may not be quite as innocent as is generally assumed. Under the proper conditions, especially in high oxidation state systems, the pyrazolyl-metal bonds appear to be able to participate easily in chemical transformations.