Highly cooperative double metalation of a bis(N2O2) ligand based on bipyridine-phenol framework driven by intramolecular pi-stacking of square planar nickel(II) complex moieties

Highly cooperative double metalation took place when a novel ligand based on a bipyridine-phenol framework was allowed to react with nickel(II) acetate. The pi-stacking of the square planar metal complex moieties is responsible for the highly cooperative double metalation judging from the X-ray crystal structure in which two complex moieties stack on top of each other in a parallel fashion.