Sonochemical synthesis of nano-scale mixed-ligands lead(II) coordination polymers as precursors for preparation of PbO and PbBr(OH) nano-structures; thermal, structural and X-ray powder diffraction studies

Nanostructured materials via green sonochemical routes - Sustainability aspects

The production of environmentally friendly nanostructured materials with well-defined properties is a major challenge. Characteristics of the nanomaterials such as dimensionality, size and morphology strongly affect their performance in various applications. Additionally, sustainability considerations require an acceptable level of efficiency while being economically feasible and environmentally benign. The use of ultrasonic irradiation (UI) is a green and powerful technology, which can be applied for the synthesis of a variety of nanostructured materials. This review critically discusses the progress made in the fabrication of environmentally benign engineered nanomaterials with various dimensionalities (i.e., zero, one, two, or three dimensions) assisted by UI. The evolution and current status in this area are further illustrated using a scientometric approach. Application of UI for the synthesis of nanostructured materials has been also assessed according to the main sustainability pillars including the performance and environmental compatibility, as well as the relevant economic and social considerations. The outlook as well as recommendations for future research has been also provided and discussed towards the promotion of sustainable nanomaterials synthesis and application in various fields.

Studies the effects of ultrasonic irradiation and dielectric constants of solvents on formation of lead(II) supramolecular polymer; new precursors for synthesis of lead(II) oxide nanoparticles

In order to evaluation the effects of ultrasonic irradiations and dielectric constants of solvents on formation [Pb₂(5-Clq-8-ol)₂(OAc)₂]_n (1), [H5-Clq-8-ol=5-chloroquinolin-8-ol and OAc^-=acetate]_, we designed some experiments and synthesized six samples of 1 under different conditions. Microrods of a lead(II) supramolecular polymer, were synthesized under these conditions. These microstructures were characterized by IR spectroscopy, X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). The results indicated that compound 1 with the best crystallinity can be obtained in the presence of MeCN and H₂O (as the bulk sample) and in the presence of MeCN and EtOH (by sonochemical process). The least agglomeration of microrods was observed in H₂O which is due to high dielectric constant of it. By considering all of the factors consist of crystallinity and agglomeration of the products and their corresponding histograms, it seems that MeCN is the best solvent for synthesis of 1. The samples which were synthesized in the presence of MeCN, had been used as new precursors for fabricating lead(II) oxide nanoparticles via thermal decomposition in oleic acid (OA).

Sonochemical preparation of pure t-LaVO4 nanoparticles with the aid of tris(acetylacetonato)lanthanum hydrate as a novel precursor

Herein a simple and fast method is introduced for the synthesis of lanthanum orthovanadate (LaVO4) nanoparticles under ultrasound irradiation. The effect of tris(acetylacetonato)lanthanum hydrate ([La(acac)3·3H2O]) and La(OAc)3 as two different precursors on the morphology and phase purity of LaVO4 was investigated. To optimum the particle size of the products, sonication time and the kind of surfactants have been changed. The as-synthesized products were characterized by XRD, FT-IR, SEM, TEM, and EDS. Based on the obtained results, it was found that the size and shape of the sonochemically formed LaVO4 nanoparticles were dramatically dependent on the sonication time, type of surfactant and lanthanum precursor. According to the XRD results, it was observed that pure tetragonal phase lanthanum orthovanadate (t-LaVO4) could be obtained only by using [La(acac)3·3H2O] as precursor under ultrasound irradiation for 30 min. On the other hand, monoclinic phase lanthanum orthovanadate (m-LaVO4) with poor crystallinity has been produced by vigorous stirring at room temperature without sonication.

Sonochemical synthesis and characterization of lead iodide hydroxide micro/nanostructures

For the first time, micro/nano-sized lead iodide hydroxide; Pb(OH)I, has been successfully prepared via a simple ultrasonic method. In this method, lead nitrate and lithium iodide were applied as starting reagents to fabricate Pb(OH)I micro/nanostructures at different conditions. The effect of different surfactants like N,N-bis(salicylidene)-ethylenediamine (H2salen), sodium dodecyl sulfate (SDS) and polyvinylpyrrolidone (PVP), sonication time, and ultrasonic intensity on the morphology and particle size of the products has been investigated. The as-produced micro/nanostructures were characterized with the aid of XRD, SEM, TEM, UV-vis, EDS and FT-IR. According to the SEM images, different morphologies of Pb(OH)I including micro- and nano-sized rods were formed by changing the preparation conditions. Based on the XRD results, it was found that Pb(OH)I and PbI2 have been produced with and without sonication at the same conditions, respectively. The use of the H2salen and sonication treatment were confirmed to be the crucial factors determining the formation of one-dimensional Pb(OH)I micro/nanostructures.

Investigations on the demetalation of metalloporphyrins under ultrasound irradiation

An efficiently facile method for the demetalation from metalloporphyrins has been developed, which uses high-intensity ultrasound to initiate the ligand dissociation in a mixed solvent of (CH(3)CO)(2)O/HCl with FeSO(4). The influences of substituents, bath temperature and reaction time on the reactions were also investigated, on the base of which the mechanism of demetalation and the effect of ultrasound irradiation on metal-ligand cleavage have been discussed in detail.