Synthesis and Characterization of a Molybdenum Alkylidyne Supported by a Trianionic OCO3– Pincer Ligand

This report details the preparation of the trianionic pincer ligand supported Mo–alkylidyne complex [tBuOCO]Mo≡CMes(THF)2 (5). The catalytic activity of [tBuOCO]Mo≡CMes(THF)2 (5) for alkyne polymerization is limited in contrast to its W-congener. Solution and crystallographic evidence for the conversion of the trianionic pincer complex [tBuOCO]Mo≡CMes(THF)2 (5) to a tetraanionic pincer complex [O2C(MesC═)Mo(η2-CH≡CtBu)(THF)] (6) upon exposure to tert-butylacetylene is provided.