2D frameworks self-assembled from a hydrazone ligand and azide salts: synthesis, structures, and luminescent property

Abstract

Three metal-organic coordination polymers {[Cu(L)(N3)]·(H2O)0.25}n (1), {[Zn(L)(N3)]·(H2O)0.5}n(2)and [Cd2(L)2(N3)2(H2O)]n(3)have been synthesized from hydrazone ligand N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide (HL), NaN3 and corresponding metal nitrates. Complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. All three complexes feature 2D coordination network in which L1– acts as NNON tetradentate ligand and azide acts as end-on bridging ligand. In complexes 1 and 2, only intra-sheet hydrogen bonding interactions are found, while the hydrogen bonding interactions between water molecules and host framework result in 3D network for 3. In addition, complexes 2 and 3 exhibited intense fluorescent emissions in the solid state at room temperature.

Keywords

• Hydrazone
• azide
• crystal structure
• luminescence property