Molecular Ladders with Multiple Interpenetration of the Lateral Arms into the Squares of Adjacent Ladders Observed for [M2(4,4‘-bpy)3(H2O)2(phba)2](NO3)2·4H2O (M = Cu2+ or Co2+; 4,4‘-bpy = 4,4‘-Bipyridine; phba = 4-Hydroxybenzoate)

Two isomorphous molecular ladders formulated as [M2(4,4‘-bpy)3(phba)2(H2O)2](NO3)2·4H2O (4,4‘-bpy = 4,4‘-bipyridine; phba = 4-hydroxybenzoate; M = Cu2+ or Co2+), shown by X-ray, feature a novel ladder motif having different inner rungs (4,4‘-bpy) and lateral arms (phba). Penetration of the lateral arms into the squares of adjacent ladders results in a novel 3-D network.