A Schiff base ligand of o-vanillin and 4-aminoazobenzene and its transition metal complexes of Ni(II), Co(II), Zn(II), Cu(II), Mn(II), and Zr(IV) were prepared under microwave irradiation as a green approach compared to the conventional method. The structures of new compounds have been characterized and elucidated via elemental and spectroscopic analyses. In addition, magnetic susceptibility, electron spin resonance, and electronic spectra of the synthesized complexes explained their geometrical structures. The thermal stability of Cu(II), Zn(II), and Zr(IV) complexes was studied by thermo-gravimetric analyses (TGA). Coats-Redfern and Horowitz-Metzger equations were used to calculate the thermal and dehydration decomposition activities of proposed structures kinetically. Surface morphologies of the solid compounds were imaged by scanning electron microscopy (SEM). The particle size of prepared complexes was measured by using a particle size analyzer at a diffraction angle of 10.9°. The geometry structures of the synthesized compounds were verified utilizing electronic spectra, ESR spectrum, and magnetic moment value. The newly synthesized compounds were screened for antimicrobial activity. Also, the anticancer activity of the free Schiff base ligand and its metal complexes were studied against two cell lines: human colon (HCT-116) and human liver cancer cells (HepG-2). The obtained results showed that the Cu(II) complex displayed the highest cytotoxic activity (IC₅₀ = 18 and 22 μg/mL for HepG-2 and HCT, respectively) compared to the free Schiff base ligand.

Two triazole Schiff base derivatives N-(furan-2-ylmethylene)-1H-1,2,4-triazole-3-amine (FTA), N-(thiophene-2-ylmethylene)-1H-1,2,4-triazole-3-amine (TTA) and their metal complexes Co(II), Ni(II), Cu(II) and Zn(II) were synthesized under microwave irradiation. The structure of these compounds has been investigated by using elemental analysis, FT-IR, UV-Vis spectrometric methods, magnetic susceptibility, mass spectra, NMR, ESR and thermal studies. The antimicrobial activities of the prepared ligands and their respective Zn (II) complexes were studied against the bacterial (positive and negative) grams and fungal strains. The inhibitive characteristics of Schiff base ligands on C-steel corrosion in hydrochloric acid were studied using weight loss measurements. The prepared Schiff base derivatives show high inhibition efficiency and their adsorption surface was found to obey Langmuir model. The data also revealed that FTA is less than TTA in terms of inhibiting efficiency.

Unfortunately, many toxic solvents are used in chemistry laboratories and in the manufacturing of materials, which poses a serious risk to process safety, the natural environment, and human health. In this review, different tools for solvent-free organic reactions have been surveyed as an approach for green chemistry, where many of the solvents are known to upset our ecosystems so an enormous research effort has been exerted during the last decade to avoid the utilization of hazardous solvents and the number of publications on solvent-free reactions has increased nearly exponentially. Obviously, this reflects the great interest in solventless reactions. In our survey, we will highlight the solvent-free organic reaction as an approach for green chemistry to cover work published up to nearly 2022.

Hydrazides 3,4, Hydrazones 6a-c, bishydrazones 8a,b, N-hydroxy-N'-arylpropanehydrazonamide 9a,b and 1-(piperidin-1-yl)-N2-arylamidrazones 10a,b were prepared under ultrasonic waves as an approach for green chemistry. a notable good yield and short reaction time were afforded under ultrasonic waves.The structures of compounds were confirmed in terms of spectroscopic and elemental analyses. The invitro antimicrobial activity of the prepared compounds were evaluated. most of compounds exhibited an excellent growth inhibition such as compounds 2, 3 and 8b against gram positive bacteria, while 2, 3, 8b, 9a, 10a and 10b against gram negative bacteria. all of tested compounds have excellent or good antifungal activity except 3

2-(2-amino-4,10-dihydrobenzo[4,5]imidazo[1,2-a][1,3,5]triazin-4-yl)phenol (ligand)and its related metal complexes of Mn (II), Co (II), Ni (II), Cu (II) and Zn (II)were prepared under microwave irradiation. The structures of prepared compounds were elucidated in terms of elemental analysis, FT-IR, UV-Vis, 1HNMR, 13CNMR, EPR spectra and mass spectra in addition to magnetic studies at room temperature and thermal properties. Elemental analysis results determined mole ratios between the ligand and metal 1:1 or 1:2. The microwave approach provides clean, shorter reaction times and enhancements in yields. Coats Redfern and Horowitz Metzger equation were used to study Thermal kinetic parameters of dehydration and decomposition of the complexes.The geometries of the ligand and its Mn (II), Co (II),Cu (II) and Zn (II) complexes were optimized using Gaussian 09 W; density functional theory (DFT) B3LYP method. Also, the cytotoxic activity of the ligand and its metal complexes were evaluated against liver cancer cells (HepG-2) and the Cu (II) complex exhibited the highest cytotoxic activity with promising IC50 value = 3.5 mu g/ml compared to standard referencecisplatin.