Polymeric Schiff base ligand (MFT) derived from 2-hydroxyacetophenone, phenylhydrazine, formaldehyde, and 2-thiobarbituric acid was synthesized via condensation reaction. The synthesized MFT ligand was complexed with the metal acetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) to form a polymeric Schiff base-metal complexes. The ligand and its metal polychelates were characterized by Fourier transform infra red (FT-IR), Ultraviolet-visible spectroscopy (UV-vis.), X-ray diffraction (XRD), Proton nuclear magnetic resonance spectroscopy (1H NMR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and Electron paramagnetic resonance spectroscopy (EPR). The EPR spectrum of MFT-Cu(II) supported a distorted octahedral or square-planar geometry. The synthesized materials were also screened against bacterial (S. aureaus, S. mutans, B. cereus, S. pyrogenes, S. viridans, S. epidermids, C. xerosis, E. coli, K. pneumonia, P. vulgaris, P. aeruginosa) and fungal strains (A. niger, F. oxysporum, and A. oryzea). Moreover, the MFT-Zn(II) complex have demonstrated good thermal stability, as well as strong antibacterial and antifungal activities compared to the ligand and other metal polychelates.

Biomediated ecofriendly method for the synthesis of nickel oxide nanoparticles using plants extracts (Toona ciliata, Ficus carica and Pinus roxburghii) has been reported. The nanoparticles so obtained were characterized by various techniques such as ultraviolet–visible, powder X-ray diffraction, Fourier transform infrared spectroscopy, attenuated total reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis and fluorescence spectroscopy. Formation of nickel oxide nanoparticles was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction where the former technique ascertains the formation of bond between nickel and oxygen. The nickel oxide nanoparticles were found to be crystalline cubic face centered and show intense photoluminescence emission at 416, 414 and 413 nm, respectively. The antibacterial activity was studied against gram positive and gram negative bacterial species by agar well diffusion method. The nickel oxide nanoparticles show better activity against some bacterial strains with reference to the standard drugs Ciprofloxacin and Gentamicin. The anthelmintic activity against Pheretima posthuma of nanomaterials obtained from Pinus roxburghii was found to be greater than that derived from Toona ciliata and Ficus carica using the standard drug Albendazole. This method takes the advantage of the sustainable and economic approach for the synthesis of metal oxide nanoparticles.

A terpolymer resin derived from Resorcinol, Formaldehyde and Salicylic acid was synthesized through condensation reaction. Transition metal ions namely Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) were incorporated into the resin forming polymer-metal complexes. Both the resin and the complexes were characterized by FTIR, UV–Vis., XRD, 1H NMR, TGA and SEM/EDX. Elemental analysis was carried out to determine the percentage of different elements present in the resin and its complexes. Conductivity measurement data showed higher conductivity of the metal complexes as compared to its precursor resin. The terpolymer resin and its metal complexes were tested against five strains of gram positive bacteria namely; S. aureus, S. mutans, S. pyrogenes, C. xerosis, C. diphtheria, and three strains of gram negative bacteria namely; E. coli, K. pneuomoniae and P. aeruginosa. All the metal complexes exhibited enhanced antibacterial properties as compared to its terpolymer resin. The Mn(II) and Co(II) demonstrated strong antibacterial activity.

Face-centered cubic structure of nickel oxide (NiO) nanoparticles with 30 nm average size was synthesized by co-precipitation method with some modification in synthesis, calcination time period and temperature. The morphology, particle size, surface area and pore size of NiO nanoparticles were determined by TEM, XRD and BET. FTIR and UV–visible analysis confirmed the formation of NiO nanoparticles. NiO nanoparticles have been used as photocatalyst for Congo red (CR) degradation from aqueous solution. The photocatalytic degradation of CR dye was analyzed by four parameters such as the concentration of CR dye, the effect of contact time, the effect of pH and dose of NiO nanoparticle catalyst. The maximum degradation of CR dye (84%) by NiO nanoparticles was determined with respect to contact time. Antioxidant activity increases as the NiO nanoparticle concentration increases. The concentration of NiO nanoparticles efficiently enhances the bacterial inhibition against gram-positive and gram-negative bacteria. The bacterial strains such as K. pneumonia 700603 and B. subtilis 5902 showed maximum zone of inhibition (15 mm) at 40 mg/ml concentration, and minimum inhibitory concentration 62.5 μg/ml by NiO nanoparticles, respectively. The photocatalytic degradation of CR and antibacterial study acknowledge that the NiO nanoparticles are efficient photocatalysts for degradation of CR dye and inhibition against different bacterial strains. NiO nanoparticles will be used to provide clean and low-cost drinking water without harmful dyes and pathogenic microbes generated in industrial wastewater.

Zinc oxide nanoparticles derived from Malus pumila (apple) and Juglen regia (walnut) plant is an attractive area of research because of their widespread use. The use of plant material to synthesize zinc oxide nanoparticles has been considered as one of the best environmentally friendly approach. This method appears to be low-cost as compare to other conventional method of synthesis. The biosynthesized nanoparticles were characterized by Ultraviolet visible spectroscopy (UV visible), Fourier transform infrared spectroscopy (FT-IR), Attenuated total reflectance spectroscopy (ATR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Transmission electron Microscopy (TEM) and Dynamic light scattering (DLS). The antioxidant potential has been evaluated by 2, 2-diphenyl-1-picrylhydrazyl free radical (DPPH) assay using L-ascorbic acid as a standard. The antibacterial activity was measured by agar well diffusion method to measure the efficacy of plant species extract and extract mediated zinc oxide nanoparticles against 5 g positive bacteria namely Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus pyrogenes (S. pyrogenes), Corynebacterium diphtheriae (C. diphtheriae) and Corynebacterium xerosis (C. xerosis) and 3 g negative bacteria such as Escherichia coli (E. coif), Klebsiella pneumoniae (K. pneumoniae) and Pseudomonas aeruginosa (P. aeruginosa) bacteria with standard antibiotic for gram positive (Ciprofloxacin) and gram negative bacteria (Gentamicin).

A phytoextract mediated synthesis of iron oxide nanoparticles using Agrewia optiva (Dhaman or Biul) and Prunus persica (Peach) leaf extract as capping and stabilizing agent without using hazardous toxic chemicals via biogenic route has been studied. The biogenic method of synthesis is convenient, rapid, cost effective and ecofriendly. The green synthesized nanoparticles were characterized by Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Attenuated total reflectance spectroscopy, X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and dynamic light scattering measurements. The antibacterial study was determined by agar well diffusion method to measure the efficiency of both phyto species extract and its mediated iron oxide nanoparticles against five gram positive bacterial stains such as Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus pyrogenes (S. pyrogenes), Corynebacterium diphtheriae (C. diphtheriae) and Corynebacterium xerosis (C. xerosis) and three gram negative bacterial stains such as Escherichia coli (E. coli), Klebsiella pneuomoniae (K. pneuomoniae) and Pseudomonas aeruginosa (P. aeruginosa). The antibiotic Ciprofloxacin and Gentamicin have been used as reference standard drugs for gram positive and gram negative bacterial stains, respectively. The antioxidant activity of the phyto extracts and prepared nanoparticles have been performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay employing L-ascorbic acid as a standard.

Development of PVA-MF blends encapsulated with NiO nanoparticles to prepare moisture-resistant polymer nanocomposite films. The preparation of PVA-MF blend was carried out by blending of MF resin and prepared PVA solutions in various ratios (2% PVA and different volumes of MF, i.e., 1.3 ml (N1), 2.2 ml (N2), 2.7 ml (N3), 3.6 ml (N4), and 4.4 ml (N5)] to optimize their ratio for nanocomposite preparation. The nanocomposite films were prepared by dispersion of NiO nanoparticles in the different ratio [N3 (0.03), N3 (0.06), N3 (0.09), and N3 (0.1)] in the optimized PVA-MF blend (N3) system. The structure, physicochemical properties, and morphology of a prepared blend and polymer nanocomposites were characterized by Fourier transform infrared (FTIR), ultraviolet-visible (UV-visible) spectroscopy, X-ray powder diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The analysis reveals that the blend and polymer nanocomposite was successfully synthesized. Electrical conductivity of PVA-MF blend (N3) has been dramatically enhanced from 0.0258 ± 0.00129 to 0.3355 ± 0.01678 S/m and reduction in the band gap of nanocomposite from 5.1 to 4.8 eV as compared to blend by doping NiO nanoparticles. The synthesized polymer nanocomposite will be used for the development of new material in electrical fields.

Macro-cyclic ligands from adipic acid, ethylenediamine with diethyloxalate and diethylmalonate and their respective metal complexes of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) with macro cyclic ligands (LO) and (LM) L [ N,N ′-bis(2-aminoethyl)hexanediamide] were synthesized successfully. These metal complexes were characterized by Fourier transform infrared, ultraviolet visible spectrometry, proton nuclear magnetic resonance spectroscopy, and mass Spectrometry, CHNS and thermogravimetric analysis. The elemental analysis confirms the structures for Mn(II), Co(II) and Ni(II) complexes similar to octahedral geometry, Cu(II) complexes as a square planar geometry and Zn(II) complexes in the tetrahedral geometry. The molar conductivities of all the metal complexes were taken in 10 −3 M DMSO, and values of all the metal complexes showed their electrolytic nature which indicates the presence of chloride ions. Thermal analysis supports as the metal complexes are thermally stable. The result of antimicrobial activity against various microorganisms confirms that the metal complexes are potent bactericides and fungicides than the ligand. Metal complexes of LO with Cu(II) and Zn(II) were found to be highly active against S. typhimurium than the complexes of LM. Graphical abstract