The synthesis of a new tridentate Schiff-base ligand and its metal complexes are reported. The reaction of ((2R)-4-methyl-2-((S)-(phenylamino)(p-tolyl) methyl) cyclohexan-1-one) with semicarbazide in a 1: 1 mole ratio resulted in the formation of the title ligand ((E)-2-((2S)-4-methyl-2-((R)(phenylamino)(ptolyl) methyl) cyclohexylidene) hydrazine-1-carboxamide)((HL). The reaction of the ligand with Co (II) and Ni (II), Cu (II), Zn (II) and Cd (II) ions in a 1: 1 (L: M) mole ratio gave the title complexes. Physico-chemical techniques were implemented, as required, to characterise the ligand and complexes. These include; elemental microanalysis, 1H, 13C-NMR and mass spectra, FT-IR and electronic spectra, magnetic susceptibility and conductance. These analyses revealed the isolation of octahedral, square planar and tetrahedral geometry about Co (II) and Cu (II); Ni (II); and (Zn (II), Cd (II)) ions, respectively. Thermal stability (TGA-DSC) of the ligand and selected complexes were also investigated. The antimicrobial activity of the ligand and its complexes against several bacterial strains and fungi species were examined. The collected data indicated that the complexes are more active against several kinds of organisms, under survey, compared with the free ligand.
in this worl three types of complexed phenolic resins were prepared using various additives such as and improving the aim of this work higher mechanical properties this work is done
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Overall enthalpy and entropy of complex formation were calculated from stability constant measurements at different tempreture also experimental results
Thermomechanical analysis (TMA) and differential scanning calorimetry (DSC) are used to investigate the effect of molding and annealing of polyester on the behavior of thermal expansion and crystallization since these factors play role in the reprocessing or recycling of the polymer. The dynamic mode of the TMA provides enhanced characterization information about the polyester since it separates the transitions into reversible and irreversible signals, and also reveals the progress of the amorphous regions as the polyester loses strength with the increasing temperature approaching melting. Slow cooling after annealing brings crystallization that may be attributed to molecular chain straightening due to orientation.
Steps were taken to obtain the Kojic acid crystals from local fungal isolation A. flavus WJF81 by separating the fermentation products from the fungus mycelium from the production plant at the centrifuge at a speed of 5000 cycles for 10 minutes. The extraction was followed by ethyl acetate then supernatant concentrate by using rotary evaporator, and dried with heat oven 37ºC. Long, yellowish, pristine acid crystals were obtained that examined the optical microscope with a magnification force of 10x and 40x. The melting point of kojic acid was determined between 152.9-153.5 °C Results of the diagnosis of Kojic acid by applying High pressure liquid chromatography HPLC technique showed that the acid was at one peak, which was close to the
... Show MoreAntibiotic resistance is the major growing threat facing the pharmacological treatment of bacterial infections. Therefore, bioprospecting the medicinal plants could provide potential sources for antimicrobial agents. Mimusops, the biggest and widely distributed plant genus of family Sapotaceae, is used in traditional medicines due to its promising pharmacological activities. This study was conducted to elucidate the antimicrobial effect of three unexplored Mimusops spp. (M. kummel, M. laurifolia and M. zeyheri). Furthermore, the mechanisms underlying such antibacterial activity were studied. The Mimusops leaf extracts revealed significant antibacterial activities against the five tested bacter
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Thermal pyrolysis kinetics of virgin high-density polyethylene (HDPE) was investigated. Thermal pyrolysis of HDPE was performed using a thermogravimetric analyzer in nitrogen atmosphere under non-isothermal conditions at different heating rates 4, 7, 10 °C/min. First-order decomposition reaction was assumed, and for the kinetic analysis Kissinger-Akahira-Sunose(KAS), Flynn-Wall-Ozawa(FWO) and Coats and Redfern(CR) method were used. The obtained values of average activation energy by the KAS and FWO methods were equal to137.43 and 141.52 kJ/mol respectively, these values were considered in good agreement, where the average activation energy value obtained by CR equation methods was slightly different which equal to 153.16 kJ/
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