Insight into non-covalent interactions in 1D Gd-based coordination polymer for solid-state self-assembly through a new supramolecular synthon

In solid-state, different non-covalent interactions between different parts of molecules play a key role in the formation of supramolecular architecture through the molecular assembly. Choice of the appropriate ligand is very crucial for such a solid. In this work, 5-phenyl-1,3,4-oxadiazole-propionate ligand and water form a one-dimensional polymer with the help of Gd(III) metal ion. Each Gd center of the polymer has a polarized amphiphilic environment. It has three water molecules on one side and a hydrophobic aromatic ligand is on a different side. This unique feature of ligand distribution help to recognize another part of the second 1D chain of the same polymer. In this way, such 1D polymer chains are self-assembled together and form an infinite 2D sheet. The hydrogen bonding between water ligands and 1,3,4-oxadiazole nitrogen of the organic ligand of two consecutive polymeric chains is the main binding force in the selfassembly process. These interactions bring aromatic rings together to form infinitely long pi-staking interactions along the chain axis. These 1D chains create a 2C1 type of topology in the solid which was found, in some cases, in the metal-organic framework, with small organic, and inorganic molecules.

Automated summary

In the solid-state, the choice of an appropriate ligand is crucial for the formation of supramolecular architecture through molecular assembly. In this study, a one-dimensional polymer is formed by the 5-phenyl-1,3,4-oxadiazole-propionate ligand and water with the help of Gd(III) metal ion. The self-assembly of these polymer chains creates an infinite two-dimensional sheet through hydrogen bonding between water ligands and the organic ligand. The formation of long pi-stacking interactions along the chain axis further stabilizes the structure.