A Two-Dimensional Supramolecular Layered Structure Constructed from Pyridine Carboxamide Molecule of 6-Bromo-N-(2-hydroxyphenyl)picolinamide

Abstract

In the course of our synthesis of luminescent materials based on benzoxazolyl-pyridine ligand, the 6-bromo-N-(2-hydroxyphenyl)picolinamide, C₁₂H₉N₂O₂Br (III), was obtained. It is a ring-opened structure of the initial 2-(6-bromopyridin-2-yl)benzo[d]oxazole ligand formed through a hydrolyzation reaction at the C-O bond of oxazole ring. It also could be seen as a condensation compound of o-aminophenol and 6-bromo-2-picolinic acid while these two aromatic ring parts show a little non-co-planar geometry in this crystal structure. Its asymmetric unit is just the whole pyridine-carboxamide molecule with Z = 8 in a unit cell. In the molecule, two intramolecular hydrogen bonding interactions could be found around the H_acylamino. Among the molecules, an aminophenol and an acylamino group of the neighbour molecule are fused via an obvious O-H···O hydrogen bond, thus a supramolecular chain structure is present. There is also p-p stacking interaction of pyridine and benzene rings between parallel stacking molecules. These hydrogen bonding and p-p stacking interactions, a supramolecular layer is constructed along the ab plane. In the unit cell, there are two supramolecular layers with ···ABAB··· stacking model. Although the supramolecular connection fashion is same in these stacking layers, the directions of the molecular planes are different, exactly orthogonality, in A and B layer.