Coinage metal complexes of multidentate Pacman phosphane ligands.

We present the extension of Pacman ligands to bidentate phosphane ligands enabling them to bind metals in their sterically protected cavity. The coordination of coinage metals shows the ability of the ligand to adopt different coordination modes by distortion, of which some additionally include the imine nitrogen atoms. Besides the coordinated metal, the substitution on the phosphorus atoms influences the type of coordination.

A Phosphorus-Based Pacman Dication Generated by Cooperative Self-Activation of a Pacman Phosphane.

Formal coordination of phosphorus(III) by a calix[4]pyrrole Schiff base ligand was achieved through the reaction of this ligand with PCl3 under basic conditions. The reaction product adopts a Pacman conformation with two P-Cl moieties, one in exo and one in endo position. It represents the first non-metal compound of calix[4]pyrrole Schiff base ligands and of Pacman ligands in general. The spatial neighborhood of the two phosphorus atoms enables cooperative reactions. As a first example, the chloride abstraction with AgOTf is presented, yielding a macrocyclic dication with two embedded phosphorus(III) monocations, which both undergo a cooperative, internal activation reaction with an adjacent C=N double bond. This intramolecular redox process affords two pentacoordinated phosphorus(V) centers within the Pacman dication. All reaction products were fully characterized and all results are supported by computations.