Structural characteristics and non-linear optical behaviour of a 2-Hydroxynicotinate-containing zinc-based metal-organic framework

Materials with non-linear optical (NLO) properties play an important role in the construction of electronic devices for optical communications, optical data processing and data storage. With this aim in mind, a Zn(II)-based metal-organic framework {[Zn₂ (nica)₂ (bpy)_1.5(H₂O)]?0.5(bpy)?3H₂O}n (1), was synthesized using 4,4-bipyridine (bpy) and a potentially bidentate ligand, 2-hydroxynicotinic acid (H2nica) with a salicylate binding moiety. A single-crystal X-ray diffraction analysis revealed that compound 1 crystallized in the orthorhombic space group Fdd2 and was composed of a three dimensional porous framework. Since Fdd2 belonged to a class of non-centrosymmetric space groups, we therefore investigated the non-linear optical behaviour of compound 1. Photoluminescence studies revealed that compound 1 exhibited a blue light emission with a maxima at 457 nm.