Structure, Bonding, and Reactivity of Room-Temperature-Stable Lithium Chloride Carbenoids

Electronic stabilization of the negative charge by a thiophosphinoyl and pyridyl/quinolyl substituent allows for the isolation of two lithium chloride carbenoids at room temperature. Molecular structure analysis by X-ray crystallography and multinuclear NMR spectroscopy reveal no direct lithium–carbon interaction in the solid state and in solution. This leads to remarkable thermal stability but also to a reduced ambiphilic character of the compounds. Thus, properties typically observed for nonstabilized Li/Cl carbenoids are less pronounced. Nevertheless, computational studies still show that despite the charge delocalization within the compound a high negative charge remains at the carbenoid carbon atom. Preliminary reactivity studies confirm this nucleophilic character and show that the carbenoids can still be used as a “carbene” source for the formation of carbene complexes.