Acyclic Diamino Carbene Complexes of Manganese(I): Synthesis, Deprotonation, and Subsequent Multiple Insertion Reaction of Alkynes

The cationic isocyanide complexes fac-[Mn(CNR)(CO)3(bipy)]+ (1) react with NH2CH3 to give acyclic diaminocarbene (ADC) complexes fac-[Mn(ADC)(CO)3(bipy)]+ (2), which when treated with KOH yield neutral formamidinyl (ADC-H) derivates fac-[Mn(ADC-H)(CO)3(bipy)] (3). These undergo multiple insertion reactions of methyl propiolate or phenyl acetylene into the metal−carbon bond to afford compounds 4 and 5 containing a new η4-azacyclohexadienyl ligand, with the loss of the bipy chelating ligand.