Ultrasonic-assisted synthesis, characterizing the structure and DFT calculation of a new Pb(II)-chloride metal-ligand coordination polymer as a precursor for preparation of α-PbO nanoparticles

The nanorods of a new Pb(II)-chloride metal-organic coordination polymer, [Pb₂Cl₂Q₂]_n(1)(HQ= 8-hydroxyquinoline) was synthesized using the sonochemical synthesis. The characteristics of the compound were determined via the elemental analysis, single-crystal X-ray analysis, scanning electron microscopy (SEM), IR spectroscopy, and powder X-ray diffraction (PXRD). The X-ray structure indicated that the compound included a 2-dimensional polymer in the solid-state with two different centers of Pb(II). Two coordination numbers (6 and 7) with two coordination spheres (symmetrical and unsymmetrical) were observed for the lead (II) centers. The structure showed a self-assembly capability with several weak interactions, such as H-bonds and π–π interactions. Sonochemical results showed the uniform, rod-like morphology of the title compound. The computational DFT results demonstrated that the HOMO (highest occupied molecular orbital) was confined primarily between one Cl^– anion and Pb centers, whereas the LUMO (lowest unoccupied molecular orbital) was roughly delocalized on the Q⁻ ligand N and O atoms comprising the other Cl^– anions. The estimated gap of HOMO–LUMO was 3.708 eV and the composite was highly shock-sensitive. The α-PbO nanostructures were produced by thermolysis of 1 at 180 °C via oleic acid as a surfactant.