Interpenetration in π-Rich Mixed-Ligand Coordination Polymers

Structural and chemical influences on interpenetration have been investigated through the preparation and structural analysis of a series of seven chiral coordination polymers using a phenylalanine-substituted naphthalene-diimide ligand (H(2)PheNDI). The reaction of H(2)PheNDI with Mu(II) or Cd-II and a range of linear dipyridyl-Based coligands forms a series of coordination polymers which vary greatly in terms of their topologies and interpenetration while largely retaining a common metallomacrocyclic motif. The metallomacrocyclic motif is found in a tube-like 1D coordination polymer poly-[Cd(bipy)(OH2)(PheNDI)] (2) and a closely related 2D polythreaded network poly-{[Cd-2-(bipy)(2)(PheNDI)(2)][Cd(bipy)(DMF)(1.5)(NO3)(2)(OH2)(0.5)]} (3) which are synthesized as pure phases under slightly different conditions. The longer 1,2-di(4-pyridyl)ethylene (dpe) ligand gives rise to a 2D coordination polymer poly-[Cd-4(DMF)(dpe)(4)(OH2)(2)(PheNDI)(4)] (5) in which the metallomacrocycles are connected only "sideways" rather than as a tube. This difference allows for 2-fold 2D -> 2D interpenetration, between two crystallographically distinct sheets, whereby the dpe passes through the metallomacrocycle, assisted by face-to-face aromatic interactions. The use of a larger dipyridyl ligand, N,N'-bis(4-pyridypnaphthalenediimide (4pyNDI), yielded 3D coordination polymers with distorted pcu topologies of the form poly-[M-2(PheNDI)(2)(4PyNDI)(2)] (M = Cd, 6; Mn, 7) which contain neither the metallomacrocyclic motif nor interpenetration.