Sonochemical synthesis of a novel nano-rod two-dimensional zinc(II) coordination polymer; preparation of zinc(II) oxide nanoparticles by direct thermolyses

A novel mixed-ligand zinc(II) coordination polymer, {[Zn(μ-4,4′-bipy)(μ-3-bpdh)(H2O)2](ClO4)2·(4,4′-bipy)0.5}n (1); 3-bpdh = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene and 4,4′-bipy = 4,4′-bipyridine, has been synthesized and characterized by IR, 1HNMR and 13CNMR spectroscopy. The single crystal X-ray data of compound 1 shows that this coordination polymer grows in two dimensions by two different bridging ligands, 4,4′-bipy and 3-bpdh. Also, nano-scale of compound 1 has been synthesized by sonochemical method and characterized by IR, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal stability of compound 1 in single crystalline and nano-scale form was carried out by thermal gravimetric (TG) and differential thermal analysis (DTA). The ZnO nanoparticles were obtained by calcination of compound 1 at 500 °C under air atmosphere and by thermolyses in oleic acid at 200 °C. The zinc(II) oxide nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Research highlights
► This study and similar reports demonstrate that coordination polymers may be suitable precursors for the preparation of nano-size material.
► The synthesis of nano-size metal oxide from nano-coordination polymer by calcination and decomposition; has not any need to special conditions like high temperature, long reaction time and pressure control.
► It is interesting to note that coordination polymers convert to nano-coordination polymer by sonication as an alternative synthetic procedure.