Cyclic Palladium Formamidinate: Synthesis, Structure, Reactivity, and Application to Suzuki-Miyaura Cross-Coupling.

The deprotonation of acyclic palladium amidine chloride () with potassium -butoxide in tetrahydrofuran results in palladium bis(formamidinate) (). undergoes a nucleophilic addition reaction with acetonitrile in the presence of PdCl or Pd(OAc) (OAc = acetate) to give dinuclear cyclic six-membered (triazapentadiene)palladium complexes ( and ). These compounds are also prepared from cyclic six-membered (tap)PdCl (; tap = triazapentadiene) or formamidinium salts (-) with Pd(OAc)/NaOAc in acetonitrile, whereas the direct reaction of with acetonitrile or acrylonitrile resulted in palladium black or an acyclic C-N-coupled product ().