Spectroscopic and Elemental Analyses of Purplish Red to Pink Spinels from Myanmar, India, Mahenge, and Tunduru (Tanzania)

Characterization of fulvic acids by elemental and spectroscopic (FTIR and 13C-NMR) analyses during composting of olive mill wastes plus straw

IntroductionAs biological activity components, α-aminophosphonates and their moieties play important roles in medicinal chemistry. Alpha-phosphonic acids are significant α-amino acid counterparts. Due to its strong biological activity, this class of molecule has recently been discovered to have numerous medical applications.Results and DiscussionA new class of α-aminophosphonates and arylidene derivatives was synthesized. Various spectroscopic and elemental analyses were used to confirm the prepared products. The produced materials were tested as anticancer against breast carcinoma cells and normal human cells (PBMC). Besides the analysis results, it was found that (7b, 4c, 5k, 6, 5a, 7c, 5f, 5b, and 5g) against MCF-7 line cells. As a reference anticancer drug, 5-fluorouracil was used. The anticancer activities showed that the compounds 7b, 4c, containing α-aminophosphonate and Schiff base groups, respectively, showed high inhibition activity against the MCF-7 cell line, with 94.32% and 92.45% inhibition compared to the inhibition by 5-FU with 96.02% inhibition. The results showed that the compounds 5k, 7b, 6, and 5a, respectively, had very low activity against normal human cells PBMC, with 12.77%, 13%, 13.13%, and 17.88% inhibition compared to the inhibition by 5-FU with 12.50% inhibition. The binding energy for non-bonding interactions between the ligand (studied compounds) and receptor, thymidylate synthase, was determined using molecular docking (pdb code: 1AN5).Conclusionα-aminophosphonate derivatives, arylidines, and disphosphonate derivatives derived from 4-hydroxybenzaldehyde were synthesized, purified, elucidated by spectroscopic analysis, and finally tested against carcinoma breast cancer to give high to moderate to low activity.

Synthesis, spectroscopic analysis, quantum chemical calculations and in silico biological activity studies of a new series of 8-aryl xanthine

The combination of boron and sulfur incorporated reduced graphene oxide (B/S-rGO) was synthesized by a simple hydrothermal technique using a novel and single source of thiophene-2 boronic acid pinacol ester. Structural and functional groups of the synthesized materials were analyzed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy analysis. The Raman analysis revealed the defective structure after incorporating sulfur and boron elements into rGO. The morphological and the presence of elements in the synthesized material were analyzed by scanning electron microscopy, transmission electron microscopy and elemental mapping analysis. The chemical states and chemical composition of B/S-rGO were observed by X-ray photoelectron spectroscopy (XPS) analysis. The electrochemical performance of the prepared material was studied using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance analysis. GCD studies were performed for B/S-rGO electrode material in an aqueous 1 M H2SO4 electrolyte. The prepared material showed a high specific capacitance of 345 Fg−1 at 1 Ag−1 in a three-electrode configuration. B/S-rGO based device exhibited 97 Fg−1 of specific capacitance at 1 Ag−1 in a symmetric two-electrode configuration. B/S-rGO based symmetric device showed a high energy density of 13.4 Whkg−1 at 249 Wkg−1 and more than 96% capacity retention after 5000 cycles.

New chemical routes to synthesize layered 2D transition metal dichalcogenides (TMDCs) are highly desired. We report here a new class of molecular precursors of general formula [MIV(SC2H4N(Me)C2H4S)2] (MIV=Ti, Zr, Hf) that offers a reliable synthetic access to 2D TMDC materials as demonstrated in the representative case of TiS2 synthesis. The complexation of the TM centers by the chelating tridentate ligand (HSC2H4)2NMe produced stable monomeric complexes, [Ti(SC2H4N(Me)C2H4S)2], [Zr(SC2H4N(Me)C2H4S)2] and [Hf(SC2H4N(Me)C2H4S)2], displaying a distorted octahedral environment around metal centers formed by four S and two N donor atoms of the ligand moiety. The characterization of molecular precursors by NMR, single‐crystal diffraction analysis, IR spectroscopy and elemental analysis confirmed the presence of metal‐sulfur bonds that are crucial in facilitating the formation of MS2 phases. Thermal decomposition behaviour of the three molecular compounds was investigated by TG‐DCS measurements that confirmed their decomposition into solid phases. Interestingly, the preorganized M−S bonds in the precursor molecules also influenced the formation of titanium disulfide thin films by chemical vapor phase deposition. The solid thin films of TiS2 were characterized by X‐ray spectroscopy analysis and atomic scale imaging. The complexes presented in this work represent a promising chemistry driven approach towards reproducible and scalable synthesis of van der Waals 2D heterostructures.

Facile synthesis of CaCO3 and investigation on structural and optical properties of high purity crystalline calcite

Experimental studies have been carried out to understand the chemical structures of the high molecular weight species produced in fuel-rich combustion systems and their role in the soot formation. Different laminar flat premixed flames at atmospheric pressure were used as a basic combustion experiments. In particular the different flames used were: Methane/O2 flames (C/O=0.60) burning at two different cold-gas flow velocities (v=4 and 5 cm/s). Benzene/O2/N2 flames (C/O=0.80) burning at two different cold-gas flow velocities (v=3 and 4 cm/s). Ethylene/O2 flames (C/O=0.80) burning at v=3 cm/s). Probe sampling and optical measurement were carried out inside the system. Condensed species and soot were withdrawn along the axis of the flame by means of a stainless-steel water-cooled probe. These species, after gravimetric determination, were subjected to chemical: gas chromatography-mass spectrometry (GC-MS), high pressure liquid chromatography (HPLC), termogravimetric analysis (TG), elemental analysis, size exclusion chromatography (SEC) and spectroscopy analysis (UV-Vis, FT-IR). Gas, Soot and PAHs analysis and formation have been also studied in a more complex system, such as a gasification apparatus as a Bubbling fluidized Bed, obtained as part of the on-going research performed at Second University of Naples, department of Environmental Sciences, on the evaluation of the effect that different reactant gases, i.e. steam, carbon dioxide and air enriched in oxygen content, as well as different bed materials, have on the composition of syngas and on the main performance parameters of co-gasification process. It has been possible to assess the following statements: The condensed material sampled in rich premixsed flames is constituted of two fraction: a lighter PAHs fraction from 2 to 7 rings, and analyzable by GC-MS tecniques and a heavier one constituted of species undetectable by GC-MS. Species not analyzable by GC-MS were separated from PAHs using a termogravimetric procedure. The high molecular mass of these species and their mixed aromatic/aliphatic character are suggested by spectroscopic analysis. By using SEC analysis, an evaluation of the molecular weights of the unknown species indicated the presence of species of 1000u along with species having molecular mass comparable with the lower mass fraction of soot (10E5-10E6u). SEC analysis of soot showed also a large contribution of species having a molecular weight of about 10E8u.

This study plays an important role in solution of beta-lactam resistance problem. This aim has been achieved by clavulanic acid production as beta-lactamase inhibitor. Beta-lactam-resistant Pseudomonas aeruginosa possesses beta-lactams resistance machinery by secretion of extracellular beta-lactamase enzyme. The present study was begun with collection of eighty nosocomial bacterial isolates from Riyadh hospitals through one year. Nosocomial bacterial isolates were treated by amoxicillin (250 µg ml -1 ) to determine resistant isolates. Among them fifty amoxicillin-resistant isolates could be found with different minimum inhibitory concentrations (MICs). However, one isolate considers the most potent which has MIC over than 1000 µg ml -1 and also was identified by using polymerase chain reaction (PCR) technique as P. aeruginosa . Isolated gene of P. aeruginosa has 870 bp. The second phase of this study was begun with collection of six plants which are growing in Saudi Arabia, then were identified by professionals of Science College herbarium, King Saud University. These plants were extracted by methanol and then dried. These plants are Rhazya stricta , Calotropois procera , Maerua crassifolia , Haloxylon salicornicum , Rumex vesicarius L. and Lycium shawii . The plant extracts were tested to detect and determine their antagonistic effect for amoxicillin-resistant P. aeruginosa and of course for its beta-lactamase enzyme. Only one extract of R. vesicarius L. has antagonistic effect for beta-lactamase enzyme. Beta-lactamase inhibitor was purified and characterized as clavulanic acid by using nuclear magnetic resonance (NMR) spectroscopy analysis, infra-red (IR) spectroscopy analysis and elemental analysis. Eventually, amoxicillin-resistant P. aeruginosa was inhibited by amoxicillin-clavulanic acid combination at 125 µg ml -1 and 128 mg ml -1 , respectively.

A series of new Schiff bases of Imesatin and Isatin derivatives which have been previously prepared from the reaction of Hydrazine monohydrate, p-phenylenediamine and 4,4- diaminodiphenylmethane with Isatin were reported. The compounds were characterized by elemental analyses, UV-visible, Infrared and Nuclear Magnetic Resonance (1H NMR and 13C NMR) spectroscopic analyses. The synthesized Schiff bases were obtained in moderate to excellent yields between 55.3 – 89.3%. Infrared spectra of all synthesized compounds contain the characteristic azomethine linkage (-CH=N) between 1580 – 1630 cm-1 and the N–H of the Isatin ring signals between δ 8.32 – 10.68 ppm in their 1H NMR spectra. The present work affords reaction pathway that is efficient and operational simplicity for the synthesis of Schiff bases derivatives. Keywords: Schiff bases, isatin, imesatin, spectroscopic analysis, biological activity

A novel Schiff base ligand (H2L) was prepared through condensation of 2,6‐diaminopyridine and o‐benzoylbenzoic acid in a 1:2 ratio. This Schiff base ligand was characterized using elemental and spectroscopic analyses. A new series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) metal complexes of H2L were prepared and characterized using elemental analysis, spectroscopy (1H NMR, mass, UV–visible, Fourier transform infrared, electron spin resonance), magnetic susceptibility, molar conductivity, X‐ray powder diffraction and thermal analysis. The complexes are found to have trigonal bipyramidal geometry except Cr(III), Mn(II) and Fe(III) complexes which have octahedral geometry based on magnetic moment and solid reflectance measurements. The infrared spectral studies reveal that H2L behaves as a neutral bidentate ligand and coordinates to the metal ions via the two azomethine nitrogens. 1H NMR spectra confirm the non‐involvement of the carboxylic COOH proton in complex formation. The presence of water molecules in all reported complexes is supported by thermogravimetric studies. Kinetic and thermodynamic parameters were determined using Coats–Redfern and Horowitz–Metzger equations. The synthesized ligand and its complexes were screened for antimicrobial activities against two Gram‐positive bacteria (Bacillus subtilis and Staphylococcus aureus), two Gram‐negative bacteria (Escherichia coli and Neisseria gonorrhoeae) and one fungus (Candida albicans). Anticancer activities of the ligand and its metal complexes against human breast cancer cell line (MCF7) were investigated. Copyright © 2016 John Wiley & Sons, Ltd.

A potentially sexadentate amino acid 1,1,1-tris(aminomethyl)ethane-N, N',N''-triacetic acid (TAMETA) was prepared by reacting its precursor amine 1,1,1-tris(aminomethyl)ethane (tame) with bromoacetic acid. The new amino acid TAMETA was characterized by elemental analysis, ir and nmr spectroscopy. Also, its Co(III) complex was prepared, isolated as a red solid, and characterized by elemental and spectroscopic analyses. In order to compare TAMETA with work reported previously on a related amino acid cis,cis-1,3,5-triaminocyclohexane-N, N',N''-triacetic acid (TACHTA), equilibrium studies in aqueous solution with Co(II), Ni(II), Cu(II), and Zn(II), and electronic solution spectra with Co(II), Ni(II), and Cu(II) were performed. The details of the preparation of the solid [Co(III)-(TACHTA)] complex which had not been reported in the earlier paper on TACHTA complexes is included here.

Many pathogenic organisms have developed resistance to many antibiotics, which leads to an increase in the spread of many microbial infections. There is an urgent need to find more effective drugs to curb widespread transmission. Hence, this study synthesized and evaluated the antimicrobial activities of mixed-ligand complexes of Cu(II), Co(II), Ni(II), Mn(II), and Zn(II) ions with barbituric acid and 1,10 phenanthroline ligands in effort to find more effective antibiotics. The complexes were characterized using elemental analysis, metal analysis, melting points, solubility tests, and spectroscopic analyses (IR and UV-visible). The antimicrobial activities of the complexes were evaluated against two gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), two gram-negative bacteria (Pseudomonas aeruginosa and Clostridium spp.), and four pathogenic fungi (Candida albicans, Aspergillus flavus, Aspergillus niger, and Saccharomyces cerevisiae). The biological activities of the metal complexes were compared to the activities of some conventional antibiotics. The molecular formulas for the complexes in 1:1:1 (L-M-L) were established based on the results of the elemental and metal analyses. The IR spectroscopic data results showed the coordination of 1,10-phenanthroline to the metal ions through the nitrogen donor atom, while barbituric acid coordinated with the metal ions through nitrogen and oxygen atoms. The formation of the complexes was confirmed by UV-visible spectroscopic data. Many of the mixed-ligand metal complexes demonstrated higher biological activities than the standard drugs and also succeeded where the conventional antibiotics failed. Therefore, the metal complexes could be considered as more efficacious antibiotics that could be added to the arsenal of effective antibiotics for the prevention of the intrinsic problems of multidrug resistance.
 Keywords: Bacteria, Fungi, Ligands, Metal complexes, Multidrug resistance, Barbituric acid

Photocatalytic-oxidation of solid state chitosan by immobilized bilayer assembly of TiO 2–chitosan under a compact household fluorescent lamp irradiation

Reaction of bis(acetylacetonato)dioxomolybdenum(VI) (MoO2(acac)2) with benzoic acid, in ethanol, yielded an oxo, ethoxide and benzoate-bridged dinuclear Mo(V) species Mo2O2(acac)2(μ-O)(μ-OC2H5)(μ-OOCC6H5) (1), with two terminal “MoO” units and one acac ligand retained on each Mo atom. This complex was analysed by IR and 1H NMR spectroscopy, X-ray crystallography and elemental analyses. The same reaction with substituted benzoic acids (o-OH)C6H4COOH, (p-Cl)C6H4COOH, (2,4-(OH)2)C6H3COOH and (o-I)C6H4COOH produced a series of dinuclear complexes, all of which were characterized by IR and 1H NMR spectroscopy and elemental analyses. Terephthalic acid ((p-COOH)C6H4(COOH)) on reaction with MoO2(acac)2 resulted in a tetramer [Mo2O2(acac)2(μ-O)(μ-OC2H5)(μ-O2C)C6H4(p-μ-O2C)Mo2O2(acac)2(μ-O)(μ-OC2H5)] (6) which was evident from the 1H NMR spectrum and elemental analyses. The role of ethanol as a reducing agent has proved instrumental in the synthesis of these dimeric Mo(V) complexes. The synthetic details and characterization by spectroscopic and X-ray crystallographic techniques are discussed.

New heterocyclic compounds containing quinoline fragment were synthesized. They were characterized by elemental analyses as well as IR and PMR spectroscopic analyses. These compounds were treated with metal (Mn(II), Ni(II) and Cu(II) salts to produce complexes. The complexes were identified and characterized by elemental analyses, IR and electronic spectral studies and magnetic moment studies. The magnetic behaviour and spectroscopic investigation of complexes indicate mononuclear octahedral structure of all the complexes. All heterocyclic compounds and metal complexes were screened for antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli and Klebsiella pneumonia using DMF as a solvent. The activity was compared with known antibiotics like Penicillin, Ampicillin, Tetracycline, Chloramphenicol and Norfloxacin.