Hydrogen Bond and π–π Interactions in a 3D Supramolecular Structure Containing 1D Helical Chains

Abstract

AbstractThe reaction of 2, 2′‐bipyridine‐6, 6′‐dicarboxylic acid (H2bpdc) with zinc nitrate and different rare earth chlorides generates two novel three‐dimensional supramolecules Zn(6‐bpc)2·2H2O (1) and Ce(bpdc)2·H2O (2) (6‐Hbpc = 2, 2′‐bipyridine‐6‐carboxylic acid). The left‐and right‐handed helical chains give rise to a 3D supramolecular framework through hydrogen‐bond and weak π–π interactions in complex 1. Interestingly, the decarboxylation occurred and the bpdc ligand was transformed into 6‐bpc species under the hydrothermal reaction in the presence of NdIII ions, while the decarboxylation did not occur when CeIII ions were used. In the structure of 2, one central Ce(IV) atom coordinates to two bpdc ligands, resulting in a discrete molecule. These discrete units are further extended into a 3D supramolecular structure through intermolecular hydrogen bonds and π–π interactions.