Interlocking of molecular rhombi into a 2D polyrotaxane network via pi-pi interactions. Crystal structure of [Cu-2( bpa)(2)(phen)(2)(H2O)](2)center dot 2H(2)O (bpa(2-) = biphenyl-4,4 '-dicarboxylate, phen=1,10-phenanthroline)

In the solid state, interlocking of the lateral phen ligands at the acute angle sites of the molecular [Cu-2(bpa)(2)-(phen)(2)(H2O)](2) rhombi via aromatic pi-pi stacking interactions into the cavities of the adjacent rhombi generates laminated polyrotaxanes that are further assembled into a 3D network via similar interactions between the phen ligands at the obtuse angle sites.