A Bis(thiophosphinoyl)methanediide Palladium Complex: Coordinated Dianion or Nucleophilic Carbene Complex?

Abstract

A question of identity: A palladium complex featuring a carbenic S,C,S-based pincer ligand is reported (see scheme). DFT calculations show that, unlike classical carbene complexes, coordination occurs through donation from a d orbital at the metal into the empty np orbital of the carbene fragment, with the nσ orbital essentially acting as a nonbonding orbital. The complex is shown to have nucleophilic character.