Reliable Formation of an Unusual and Chiral Two-Dimensional Network Containing Entanglement of the Ligand in the Presence of Different Anions

The coordination polymers of the ligand N,N′-bis(4-pyridyl)suberamide (1a) with Cu(II) were explored in the presence of anions such as bivalent SO42− and SiF62− and univalent NO3−1. It was found that the ligand with Cu(II) ion consistently forms an unusual two-dimensional layer containing (4,4)-topology irrespective of the anions present. In the layer, the alkyl chains are entangled via weak hydrophobic interactions such that the chirality is generated in the layer. The entangled spacers occupy grid cavities with dimensions of 12 × 12 Å. These layers are further linked via hydrogen bonds between amide N−H groups and anions (SO42− or SiF62−).