Sonochemical Synthesis and Characterization of the New Micro-Hexagonal-Rod Lead (II)-Azido Coordination Compound

Lead(II)-Azido Metal-Organic Coordination Polymers: Synthesis, Structure and Application in PbO Nanomaterials Preparation

The current study aims to explain recent developments in the synthesis of Pb(II)-azido metal-organic coordination polymers. Coordination polymers are defined as hybrid materials encompassing metal-ion-based, organic linkers, vertices, and ligands, serving to link the vertices to 1D, 2D, or 3D periodic configurations. The coordination polymers have many applications and potential properties in many research fields, primarily dependent on particular host-guest interactions. Metal coordination polymers (CPs) and complexes have fascinating structural topologies. Therefore, they have found numerous applications in different areas over the past two decades. Azido-bridged complexes are inorganic coordination ligands with higher fascination that have been the subject of intense research because of their coordination adaptability and magnetic diversity. Several sonochemical methods have been developed to synthesize nanostructures. Researchers have recently been interested in using ultrasound in organic chemistry synthetics, since ultrasonic waves in liquids accelerate chemical reactions in heterogeneous and homogeneous systems. The sonochemical synthesis of lead-azide coordination compounds resulted from very fantastic morphologies, and some of these compounds are used as precursors for preparing nano lead oxide. The ultrasonic sonochemistry approach has been extensively applied in different research fields, such as medical imaging, biological cell disruption, thermoplastic welding, food processing, and waste treatment. CPs serve as appropriate precursors for preparing favorable materials at the nanoscale. Using these polymers as precursors is beneficial for preparing inorganic nanomaterials such as metal oxides.

‘Simple’ Oligopyridine Complexes – Sources of Unexpected Structural Diversity

The simple formulae often presented for main-group metal complexes of oligopyridines (typically 2,2′-bipyridine, 1,10-phenanthroline, and 2,2′:6′,2″-terpyridine) hide a wide variety of polymeric solid-state structures. We present an overview of these structures and reveal a plethora of 1D chains, including ladder assemblies, and 2D networks. In most assemblies, the polymeric backbone or network is defined by the metal atoms and bridging ligands other than oligopyridines. The heterocyclic ligands typically feature as peripheral decorations, often engaging in face-to-face supramolecular π-stacking interactions which define the assembly of the crystal. In 1D coordination polymers, three types of decoration predominate which we have defined as Type 1 (all the oligopyridines on the same side and π-stacked), Type 2 (alternating arrangement of oligopyridines), and Type 3 (a pairwise alternating structure).

Synthesis of Amino-Functionalized Waste Wood Flour Adsorbent for High-Capacity Pb(II) Adsorption

An innovative wood flour-based adsorbent for Pb(II) removal was synthesized via a cost-effective and environment-friendly method, which could be high on the priority list owing to its high absorption capacity. By increasing the specific surface and introducing functional groups through delignification and amination, the experimental adsorption capacity of the prepared adsorbent could reach 189.9 mg/g in 180 min (pH = 4, T = 293 K, dosage = 1 g/L, and ion concentration = 300 mg/L). This value is higher than most of those achieved in previous studies on wood-based adsorbents. Pseudo-second-order and Langmuir models were utilized to describe the adsorption kinetics and isotherms, respectively. The effects of solution pH, adsorbent dosage, and temperature on the adsorption efficiency were also evaluated. With a low decrease rate of 20.2% in five cycles, the adsorbent possessed reusability. The adsorbents exhibited high selectivity in the Pb(II), Cu(II), and Zn(II) mixed solution, and the selectivity coefficient k of adsorbents to Pb(II) could reach approximately 2.74 in triad. The method could prompt the development of cost-effective methods for the removal of heavy metals from wastewater.

Thermolysis synthesis of pure phase NiO from novel sonochemical synthesized Ni(II) nano metal-organic supramolecular architecture

Nano-structures of a new supramolecular coordination compound of divalent nickel with the pyrazol (pzH) containing the terminal azide anions, [Ni(pzH)₂(N₃)₂] (1), with discrete molecular architecture (DMA) in solid state was synthesized via sonochemical method. The new nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction, IR, and elemental analysis. Compound 1 was structurally characterized by single crystal X-ray diffraction and the single-crystal X-ray data shows that the coordination number of Ni (II) ions is six, (NiN₆), with four N-donor atoms from neutral "pzH" ligands and two N-donors from two terminal azide anions. The supramolecular features in these complexes are guided and controlled by weak directional intermolecular interactions. The structure of the title complex was optimized by density functional theory calculations. Calculated structural parameters and IR spectra for the title complex are consistent with the crystal structure. The NiO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant.

Synthesis and characterization of nano-peanuts of lead(II) coordination polymer [Pb(qcnh)(NO3)2]n with ultrasonic assistance: A new precursor for the preparation of pure-phase nano-sized PbO

A sonochemical method was used to synthesize nano-peanuts of a new lead(II) coordination 1D polymer, [Pb(qcnh)(NO₃)₂]_n (1), where qcnh=2-quinolincarbaldehyde nicotinohydrazide. The compound was characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and single crystal X-ray analysis. The X-ray structure revealed that the Pb(II) atom is coordinated by one oxygen and three nitrogen atoms from two qcnh ligands and five oxygen atoms from three nitrate ligands in an 8+1 fashion with a PbN₃O₆ donor set. One of the PdN distances in the vicinity of the central atom is a bit longer (Pb1N1=2.939(4) Å), which shows the effect of the 6s² lone electron pair localized within the valence shell of the lead(II) atom. PbO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XRD to be 28nm. The morphology and size of the prepared PbO nanoparticles were further studied using SEM.

Sonochemical syntheses of binuclear lead(II)-azido supramolecule with ligand 3,4,7,8-tetramethyl-1,10-phenanthroline as precursor for preparation of lead(II) oxide nanoparticles

The new neutral binuclear lead(II) azido coordination compound, [Pb ₂(tmph) ₂(μ-N₃)₂(CH₃COO) ₂] (1) [tmph = 3,4,7,8-tetramethyl-1,10-phenanthroline], has been synthesized by a sonochemical method. Single crystal X-ray structure shows that the overall structure of 1 is binuclear unit. Complex 1 has a bridging azido pathway, end-to-end bridging azides between a pair of lead(II) centers. This is further extended into a one-dimensional (1D) and three-dimensional (3D) supramolecular structure by Pb⋯C and π–π weak directional intermolecular interactions. The coordination number of lead(II) ions is seven, PbN₄O₃, with two N-donor atoms from tmph ligands and three O-donors from acetate anions and two N-donors from two azide anions. It has a "stereo-chemically active" electron lone pair, and the coordination sphere is hemidirected. The PbO nanoparticles were obtained by thermolysis of 1 at 180 °C with oleic acid as a surfactant. The morphology and size of the prepared PbO samples were further observed using scanning electron microscopy (SEM).