Unexpected orthopalladation of acetophenonephenylhydrazone

A singular hydrazonato complex of palladium has induced the unexpected orthometallation of acetophenonephenylhydrazone on the phenyl group. This is the first X-ray characterized example of an orthopalladated E-arylhydrazone of general formula ArC(R″)NNHAr′ where the metallated aryl is Ar′ although palladation on Ar is not hindered. Structural evidence suggests that the PdN(amido) bond that is present in the starting material induced the palladation of the unexpected phenyl.