Geometries of stacking interactions between phenanthroline ligands in crystal structures of square-planar metal complexes.

Stacking interactions of phenanthroline square-planar complexes in crystal structures were studied by analyzing data from the Cambridge Structural Database. In most of the crystal structures, two phenanthroline complexes were oriented "head to tail." Phenanthroline complexes show a wide range of overlap geometries in stacking interactions, while short metal-metal distances were not observed. Stacking chains with alternating overlaps were the predominant type of packing in the crystal structures.