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 [ t BuOCO]Mo≡CMes(THF) 2 ( 5 ). The catalytic activity of [ t BuOCO]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 [ t BuOCO]Mo≡CMes(THF) 2 ( 5 ) to a tetraanionic pincer complex [O 2 C(MesC═)Mo(η 2 -CH≡C t Bu)(THF)] ( 6 ) upon exposure to tert -butylacetylene is provided.